Chapter 5 Regions

Each Region within the Pacific Salmon Explorer has specific attributes related to management regimes, data collection, documentation protocols, and most importantly, salmon populations and habitats (Figure 5.1). Here, we document Region-specific data sources, methodological considerations, and social processes used in each of the initial biological status, habitat pressure assessments, and any other unique information for each region currently within the Pacific Salmon Explorer.

Figure 5.1: Map of the PSE Regions.

5.1 Northern Transboundary Region

At the northwestern edge of BC lie some of the most remote and rugged salmon-bearing river basins in the province, including the Alsek, Chilkat, Taku, Whiting, Stikine, and Unuk. These river basins span Territories of the Champagne and Aishihik First Nations, Taku River Tlingit, and Tahltan First Nations and the international border between Canada and the United States (US). Salmon spawn in the headwaters of Canadian rivers and lakes and migrate out to the ocean in southeast Alaska. This northern Transboundary Region hosts five species of Pacific salmon and steelhead, including 0 CUs: 0 Chinook, 0 chum, 0 coho, 0 pink, 0 river-type sockeye, 0 lake-type sockeye, and 0 steelhead CUs (Appendix 1).

The first round of data compilation and local consultation in the Transboundary Region took place from 2021-2024 in collaboration with a Transboundary Technical Working Group, made up of fisheries staff from the Tahltan Central Government, Taku River Tlingit First Nation, the Champagne and Aishihik First Nations, and DFO Regional Biologists, as well as independent salmon experts. This work was funded by the BC Salmon Restoration and Innovation Fund. We also retained Gottfried Pestal (Solv Consulting) to assist in compiling Transboundary population data and providing technical advice on the feasibility of estimating certain indicators.

5.1.1 Population Data and Analytical Methods

Because of the Transboundary life-cycles of salmon in this region, most monitoring data are focused on mandatory reporting under the Pacific Salmon Treaty between Canada and the US. Specifically, we relied heavily on data in the Transboundary Technical Committee (TTC) reports and associated appendices (Transboundary Technical Committee 2022). Data in published reports often lag behind data collection by 2-3 years, and we were able to obtain up-to-date version of report appendices from DFO on request (Aaron Foos, pers. comm.). The TTC reports are focused on “Treaty stocks”, equivalent to Stock Management Units, for Chinook, coho, and sockeye in the major river basins (Alsek, Stikine, Taku). Information on CUs outside of these Treaty stocks was sparse.

5.1.1.1 Spawner Surveys

Annual spawner survey data were mostly acquired from NuSEDS and the TTC annual reports. There are over 20 appendices in the annual TTC reports that include escapement estimates from assessment projects including fishwheels, weirs, video weirs, sonars, snorkel surveys and aerial surveys. Where spawner estimates were reported in both datasets, they were most often identical. For some streams and years, the TTC estimates were lower. For example, the Klukshu River Chinook, coho, and sockeye estimates from 2000-2020 were often lower in the TTC reports than in NuSEDS. There were fewer cases where TTC estimates were higher than NuSEDS and these differences tended to be smaller in magnitude.

Based on guidance from the TWG, who advised that data in TTC reports were more reliable and current than in NuSEDS, we preferentially relied on TTC data when spawner surveys were reported in both sources. In some cases (e.g. Klukshu River coho), the NuSEDS time series extended further back in time than the TTC data, but estimates differed between the two sources in more recent years. In these cases, we used only the TTC data, even though that meant losing some historical data that were in NuSEDS, to avoid misrepresenting changes in abundance through time that are due to different data processing steps between data sources.

We report the published estimates directly from the TTC or NuSEDS for all spawner surveys except the Taku River survey of the Northern Transboundary Fjords river-type sockeye CU. In this case, the Taku River sockeye reconstruction from TTC includes the river-type sockeye CU and four lake-type sockeye CUs. Since 2004, all four lake-type sockeye CUs have weirs and thus their contribution to can be accounted for to estimate the river-type component of the overall Taku River sockeye. We do not report spawner survey data for Taku River prior to 2004, when the estimates could not be attributed to CUs.

There were two additional spawner surveys that we extracted from sources other than the TTC reports and NuSEDS. A sonar project on the Nahlin River, funded by the Pacific Salmon Commission’s Northern Fund, provided Chinook estimates from 2016 – 202336. The sonar project targets large Chinook (>659 mm mid-eye to fork length) and the estimates are separate from the Nahlin River Chinook estimates in the TTC report. In addition, the Lynn Canal Chinook CU was monitored from 1981-1991 at Stonehouse Creek (Pahlke 1992).

Along with spawner survey counts, we compiled additional information including species, site, year, quality, and method and synthesized these data by CU. Spawner survey method and data quality are consistently reported in NuSEDS, but often had to be extracted from footnotes or within the text for TTC-reported data.

Table 5.1: Data sources for 65 spawner surveys in the Transboundary region. In some cases, data were available both from NuSEDS and from the TTC, in which case we preferentially source data from the TTC appendices. The TTC Series refers to the specific Appendix and variable name from the TTC reports (note appendix numbers reflect reports from 2024 onward).

Species	Conservation Unit	Stream Name	Indicator	Source	TTC Appendix & Series
CK	Alsek	Alsek River	N	TTC	E.7. Alsek Escapement
CK	Alsek	Blanchard River	N	TTC	E.8. Blanchard River Aerial Index
CK	Alsek	Goat Creek	Y	TTC	E.8. Goat Creek Aerial Index
CK	Alsek	Klukshu River	Y	TTC	E.5. Klukshu - Escapement
CK	Alsek	Takhanne River	Y	TTC	E.8. Takhanne River Aerial Index
CK	Lynn Canal	Stonehouse	N	Pahlke (1992)
CK	Stikine-Early Timing	Beatty Creek	N	TTC	B.13. Beatty Aerial
CK	Stikine-Early Timing	Christina Creek	N	NuSEDS
CK	Stikine-Early Timing	Little Tahltan River	Y	TTC	B.34. Little Tahltan natural spawners
CK	Stikine-Early Timing	Tahltan River	N	NuSEDS
CK	Stikine-Late Timing	Iskut River	N	NuSEDS
CK	Stikine-Late Timing	Katete River	N	NuSEDS
CK	Taku-Early Timing	Dudidontu River	Y	TTC	D.8. Dudidontu Aerial Index
CK	Taku-Early Timing	Nahlin River	Y	TTC	D.8. Nahlin Aerial Index
CK	Taku-Early Timing	Nahlin River Sonar	N	Aaron Foos (pers. comm.)
CK	Taku-Early Timing	Tseta Creek	Y	TTC	D.8. Tseta Aerial Index
CK	Taku-Late Timing	Hackett River	N	NuSEDS
CK	Taku-Late Timing	Kowatua River	Y	TTC	D.8. Kowatua Aerial Index
CK	Taku-Late Timing	Tatsatua River	Y	TTC	D.8. Tatsamenie Aerial Index
CK	Taku-Mid Timing	Nakina River	Y	TTC	D.8. Nakina Aerial Index
CM	Taku	Canyon Island	N	TTC	D.24. Canyon Island Fishwheel Raw Count
CO	Alsek	Klukshu River	Y	TTC	E.15. Klukshu Escapement
CO	Lower Stikine	Bronson Creek	N	TTC	B.30. Bronson Slough Aerial Index
CO	Lower Stikine	Christina Creek	N	TTC	B.30. Christina Creek Aerial Index
CO	Lower Stikine	Craig River	Y	TTC	B.30. Craig River Aerial Index
CO	Lower Stikine	Katete River	Y	TTC	B.30. Katete River Aerial Index
CO	Lower Stikine	Porcupine River	Y	TTC	B.30. Porcupine Slough Aerial Index
CO	Lower Stikine	Scud River	Y	TTC	B.30. Scud Slough Aerial Index
CO	Lower Stikine	Verrett River	Y	TTC	B.30. Verrett River Aerial Index
CO	Lower Stikine	West Katete River	Y	TTC	B.30. West Katete River Aerial Index
CO	Taku-Early Timing	Dudidontu River	N	NuSEDS
CO	Taku-Early Timing	Nahlin River	N	NuSEDS
CO	Taku-Late Timing	Flannigan Slough	N	NuSEDS
CO	Taku-Mid Timing	Hackett River	N	NuSEDS
CO	Taku-Mid Timing	Little Trapper Lake	N	NuSEDS
CO	Taku-Mid Timing	Tatsatua River	N	NuSEDS
PKE	Transboundary Fjords (even)	Canyon Island	N	TTC	D.24. Canyon Island Fishwheel Raw Count
PKE	Transboundary Fjords (even)	Nakina River	N	NuSEDS
PKO	Transboundary Fjords (odd)	Canyon Island	N	TTC	D.24. Canyon Island Fishwheel Raw Count
PKO	Transboundary Fjords (odd)	Nakina River	N	NuSEDS
SEL	Christina	Christina Creek	N	TTC	B.25. Christina Creek Aerial Index
SEL	Chutine	Chutine River	Y	TTC	B.25. Chutine River Aerial Index
SEL	King Salmon	King Salmon Lake	Y	TTC	D.16. King Salmon Total Spawning Escapement
SEL	Klukshu	Klukshu River	Y	TTC	E.10. Klukshu - Escapement
SEL	Kuthai	Kuthai Lake	Y	TTC	D.19. Kuthai Lake Spawning Escapement Total
SEL	Little Trapper	Little Trapper Lake	Y	TTC	D.15. Little Trapper Spawning Escapement Total
SEL	Nesketahin	Nesketahin Lake	N	TTC	E.13. Neskataheen Lake Aerial Index
SEL	Nesketahin	Village Creek	Y	TTC	E.13. Village Creek Counter
SEL	Tahltan	Tahltan River	Y	TTC	B.32. Tahltan Lake - Counts after harvest samples
SEL	Tatsamenie	Tatsamenie Lake	Y	TTC	D.14. Tatsamenie Spawning Escapement Total
SEL	Tatsamenie	Tatsatua River	N	NuSEDS
SER	Alsek (river-type)	Tatshenshini River	N	NuSEDS	E.13. Tatshenshini River Aerial Index
SER	Northern Transboundary Fjords (river-type)	Bronson Creek	Y	TTC	B.25. Bronson Slough Aerial Index
SER	Northern Transboundary Fjords (river-type)	Craig River	N	TTC	B.25. Craig River Aerial Index
SER	Northern Transboundary Fjords (river-type)	Hackett River	N	NuSEDS
SER	Northern Transboundary Fjords (river-type)	Nahlin River	N	TTC	Nahlin River Weir
SER	Northern Transboundary Fjords (river-type)	Nakina River	N	NuSEDS
SER	Northern Transboundary Fjords (river-type)	Porcupine River	Y	TTC	B.25. Porcupine Slough Aerial Index
SER	Northern Transboundary Fjords (river-type)	Scud River	Y	TTC	B.25. Scud River Aerial Index
SER	Northern Transboundary Fjords (river-type)	Stikine River	Y	TTC	B.26. Escapement - Mainstem
SER	Northern Transboundary Fjords (river-type)	Taku River	Y	TTC	D.17. Natural Spawning Escapement
SER	Northern Transboundary Fjords (river-type)	Tuya River	N	NuSEDS
SER	Northern Transboundary Fjords (river-type)	Verrett River	Y	TTC	B.25. Verret River Aerial Index
SER	Northern Transboundary Fjords (river-type)	Verrett Slough	Y	TTC	B.25. Verret Sloughs Aerial Index
SH	Taku Summer	Canyon Island	N	TTC	D.24. Canyon Island Fishwheel Raw Count

5.1.1.2 Juvenile Surveys

Juvenile survey data were available from the TTC report (Transboundary Technical Committee 2022) for Tahltan lake-type sockeye in the Stikine watershed and Tatsamenie lake-type sockeye in the Taku watershed. Both of these CUs report natural-origin and hatchery-origin juveniles.

5.1.1.3 Hatchery Releases

Data on hatchery locations, release sites, and release numbers are provided by DFO Salmon Enhancement Program staff. We compiled information on hatchery releases at 10 different locations throughout the Transboundary Region, representing 13 different location and CU combinations.

5.1.1.4 Spawner Abundance

The available data from the TTC (Transboundary Technical Committee 2022) provide CU-level estimated spawner abundance for eight of the 44 CUs in the Transboundary Region. These CUs are located in the Alsek, Stikine, and Taku River basins. Seven of these CUs are lake-type sockeye with a weir at the downstream extent of the CU (i.e. outlet of the lake) such that this spawner survey can also provide the CU-level estimated spawner abundance. One Chinook CU (Alsek Chinook) has reliable spawner survey data at the Klukshu River that is expanded to represent the entire CU. There are no CU-level spawner abundances for CUs in the Chilkat, Unuk, or Whiting watersheds, or for the coho, chum, pink and steelhead CUs of the Region.

5.1.1.5 Run Timing

Run timing for Transboundary CUs was compiled from several sources. Start, peak, and end migration dates for Taku River lake-type sockeye CUs were based on migration past the Canyon Island fish wheel reported by Pestal et al. (2020). Tahltan lake-type sockeye daily passage through the Tahltan fence is reported in the TTC reports (Transboundary Technical Committee 2022). Data compilation and treatment are detailed in Wilson and Peacock (In review). See Overview of Population Indicators: Run Timing for a description of the run timing indicator and methods.

5.1.1.6 Catch & Run Size

The TTC reports on weekly harvest and effort, annual harvest, and annual estimates of catch (based on coded-wire tags – CWT – or genetic stock identification – GSI) in US and Canadian commercial, recreational, and First Nations fisheries for specific Stock Management Units (SMUs) and indicator populations covered by the Treaty. From TTC report (Transboundary Technical Committee 2022), estimates of spawners, Canadian catch, US catch, and run size are available for the following SMUs: Alsek Chinook, Alsek sockeye, Stikine Chinook, Stikine sockeye, Taku Chinook, Taku coho, and Taku sockeye. In the Stikine, the catch and run size information is further split into the mainstem and Tahltan River components. Based on these data, we provide CU-level estimates of catch and run size for the Alsek Chinook CU and the Tahltan lake-type sockeye CU.

5.1.1.7 Recruits-per-Spawner

There were no recruits-per-spawner data available at the CU-level for the Transboundary Region.

5.1.1.8 Biological Status

Given that no spawner-recruit data were available for Transboundary CUs, we could only apply percentile benchmarks to assess biological status to eight CUs that had estimated spawner abundance. Given a lack of CU-scale information on spawner abundance, the other 36 CUs could not be assessed. These included all coho, pink, chum, and steelhead CUs in the Transboundary Region.

5.1.2 Habitat Data and Analytical Methods

5.2 Haida Gwaii Region

The archipelago of Haida Gwaii is located off the North Central Coast of BC (Figure 5.2), composed of two main islands; Graham Island (northern) and Moresby Island (southern), with hundreds of other smaller islands in total composing nearly 10,000 square kilometers. The Hecate Strait separates Haida Gwaii from mainland British Columbia by about 100 kilometers. Salmon-bearing waters on Haida Gwaii range from an abundance of small streams along the many kilometers of coastline to larger well-known salmon rivers such as the Yakoun and Tlell Rivers. All five species of Pacific salmon spawn and rear on Haida Gwaii within 30 CUs. These CUs include: 2 Chinook, 5 chum, 3 coho, 3 pink (even-year), 3 pink (odd-year), 10 sockeye (lake-type), 3 sockeye (river-type), and 1 steelhead CU. The process of data gathering and synthesis to complete the initial assessments within the Haida Gwaii Region was completed over one year (2021).

In order to develop the Pacific Salmon Explorer for Haida Gwaii, we engaged with the Haida Nation, DFO, the Gowgaia Institute, Parks Canada, and other salmon experts in Haida Gwaii. We received input and feedback throughout the engagement processes, which included an in-person meeting in September 2021, meeting follow-up, and extended outreach.

Based on feedback and local knowledge, we received contextual knowledge on salmon populations within the region, described within Population Data and Analytical Methods, and were able to improve upon forestry data with contributions from the Gowgaia Institute (described in Habitat Data and Analytical Methods).

5.2.1 Conservation Unit Changes

Based on feedback from the Haida Gwaii Technical Working Group, the name of the Marian Lake sockeye conservation unit was renamed to “Marian/Eden.” The original name developed by DFO (Holtby and Ciruna 2007) and in DFO’s New Salmon Escapement Database was “Marian” however, TWG members indicated that most of the salmon and surveys are in Eden Lake, and a recent DFO IFMP for Northern Salmon listed “Marian/Eden” rather than “Marian” (Fisheries and Oceans Canada (DFO) 2019). Additionally, while defined by Holtby and Ciruna (2007) as a Conservation Unit, DFO did not have a CU boundary defined for this CU. We defined the CU boundary as the same spatial extent as the spawning habitat for Marian Lake (which encompasses the watersheds that contain Marian Lake, Eden Lake, and Roy Lake).

Figure 5.2: Map of the Haida Gwaii Region.

5.2.2 Population Data and Analytical Methods

As with the Skeena and Nass regions, in the Haida Gwaii Region many of the datasets necessary to understand the dynamics of salmon CUs have been compiled and stored through the North and Central Coast (NCC) Database [English et al. (2018); see Skeena Region]. Details on specific data sources, analytical methods, and nuances specific to the Haida Gwaii Region are described below.

5.2.2.1 Spawner Surveys

Spawner survey data for streams in the Haida Gwaii Region were sourced from DFO’s New Salmon Escapement Database (NuSEDS). For a description of the spawner survey indicator, see Overview of Population Indicators: Spawner Surveys.

5.2.2.2 Juvenile Surveys

Juvenile abundance data for CUs in the Haida Gwaii were available from Haida Fisheries for a coho juvenile outmigration program at Deena River in the East Haida Gwaii coho CU. We will update this information as other juvenile data becomes available. For a description of the juvenile survey indicator, see Overview of Population Indicators: Juvenile Surveys.

5.2.2.3 Hatchery Releases

Hatchery releases in the Haida Gwaii Region for all salmon species were provided by DFO (Brock Ramshaw, Salmonid Enhancement Program). Data on hatchery locations, release sites, and release numbers from the Freshwater Fisheries Society of BC are available through the Province of British Columbia’s BC Data Catalogue. Refer to Overview of Population Indicators: Hatchery Releases for details on data and analytical methods.

5.2.2.4 Spawner Abundance

Observed spawner abundance for CUs on the in the Haida Gwaii Region is the sum of all spawner survey data as documented in NuSEDS, as described in Overview of Population Indicators: Spawner Abundance.

Haida Gwaii CU-level estimates of spawner abundance (run reconstructions) were sourced from the North and Central Coast (NCC) database, updated by PSF for the years 2018-2021. Haida Gwaii CU-level estimated spawner abundance time series were developed for the NCC database according to the expansion factors described in the Skeena Region section above. On Haida Gwaii, the decline in monitoring coverage over the last 10-20 years was mentioned as an area of concern, and a decline in assessments may affect the relationships used to develop total estimates of spawner abundance (run reconstructions), as described in Data Quality.

5.2.2.5 Run Timing

Run timing data were compiled from a variety of sources detailed in Wilson and Peacock (In review). See Overview of Population Indicators: Run Timing for a description of the run timing indicator and methods.

5.2.2.6 Catch & Run Size

Catch and run size and subsequent exploitation rates for CUs on the Haida Gwaii Region were calculated by LGL and PSF from data in the Fisheries Operating System (FOS) and other DFO databases. Similar to our work in other adjacent regions (Central Coast, Skeena, Nass), we accessed most of these datasets via the North and Central Coast (NCC) database, maintained by LGL Ltd. and updated by PSF for the period 2018-2021 (English et al. 2018). The data is current to 2021. For a description of catch and run size methods, see Overview of Population Indicators: Catch & Run Size.

On Haida Gwaii, there are some specific nuances to catch data that are important to be aware of when considering the role of catch in estimates of total annual salmon run size. For sockeye salmon, the catch is calculated from a fixed estimate of an annual exploitation rate of 20%. Local knowledge suggests this value may be high, but the representativeness of a fixed rate is less likely to capture annual differences. There is only one Coded Wire Tag indicator stock for coho salmon, so these values are applied to all other coho when used in catch calculations. These considerations in estimates of catch are discussed in Data Quality.

5.2.2.7 Recruits-per-Spawner

Recruits-per-spawner data for CUs in the Haida Gwaii Region were derived from the DFO age database and CU-level estimates of spawner abundance and catch and run size accessed from the North and Central Coast (NCC) database (English et al. 2018). For a description of recruits-per-spawner methods, see Overview of Population Indicators: Recruits-per-Spawner.

5.2.2.8 Biological Status

The biological status assessments for CUs in the Haida Gwaii Region currently reflect data sourced from the North and Central Coast (NCC) database that are current to 2021. As new data become available, we will update the analyses and results in this report as well as on the Pacific Salmon Explorer. See Sections 4.1.4. Benchmarks for Assessing Biological Status and 4.1.5. Decision Rules for Assessing Biological Status for more details on biological status assessment methods.

5.2.3 Habitat Data and Analytical Methods

Nuances regarding habitat pressure indicator data and analytical methods for the Haida Gwaii Region are listed below. Refer to Habitat Status: Indicators & Benchmarks for information on habitat pressure indicators, benchmarks, and the analytical methods used to assess habitat status.

5.2.3.1 Spawning Zones of Influence

Methods for delineating Chinook CU spawning zones of influence (ZOIs) vary by region in accordance with the CU delineation approach used by DFO. In the Skeena, Nass, Central Coast, and Haida Gwaii regions, Chinook CUs are defined using a more restrictive geographic representation, which resulted in fewer (or no) spawning locations occurring within the CU boundaries. As such, spawning ZOIs for each Chinook CU were delineated using the extent of all 1:20K FWA Assessment Watersheds that directly intersected with Haida Gwaii Chinook CU boundaries.

5.2.3.2 Spatial Data Processing for Habitat Pressure Indicators

5.2.3.2.1 Forest Disturbance on Haida Gwaii

Working with John Broadhead and Dave Leversee of the Gowgaia Institute, we accessed the best available logging history (harvested areas) dataset compiled for Haida Gwaii. The Gowgaia Institute produced this logging history dataset as part of the Riparian Fish Forest on Haida Gwaii project (Broadhead 2009), and they updated this dataset to 2021. The Gowgaia dataset provided a more complete representation of forest disturbance on Haida Gwaii than was available in the VRI and Consolidated Cutblocks datasets that we used to assess forest disturbance in other regions to date. The spatial data processing method for forest disturbance on Haida Gwaii was updated to source the Gowgaia dataset.

With their expert knowledge of logging history on Haida Gwaii, the Gowgaia Institute also identified areas where assessing risk at the assessment watershed scale may over or underrepresent more localized risk. Categorizing risk at the assessment watershed-scale generalizes risk across watersheds. As such, at this scale, it is not possible to identify whether risk is evenly distributed across a watershed or is more concentrated in certain parts of a watershed. Areas that the Gowgaia Institute identified as suffering from this limitation were Haines Creek and watersheds on NE Graham Island, where much of these areas are unimpacted by harvesting; they were categorized as moderate risk due harvesting that occurred in concentrated areas of these watersheds.

5.2.3.3 Spawning Habitat Information from Expert Knowledge Holders

In addition to the spawning habitat information we acquired from DataBC (primarily from the Fisheries Information Summary System (FISS) database), we collaborated with representatives from Haida Fisheries, Fisheries and Oceans Canada’s Salmon Enhancement Program, Parks Canada, the Gowgaia Institute, the Hecate Strait Streamkeepers, and independent salmon experts to identify local salmon spawning locations. The collective identified 16 new salmon-bearing watersheds that had not been previously documented, further enhancing the baseline of available information for Haida Gwaii salmon.

5.3 Nass Region

In northern BC, the Nass River watershed is the third-largest watershed in the province and includes several major tributaries, including the Bell-Irving, Cranberry, Meziadin, Kwinageese, and Damdochax Rivers. The Nass Region (Figure 5.3), which consists of the watersheds draining into Portland Canal and Observatory Inlet, contains extensive spawning and rearing habitat for all five species of Pacific salmon. These salmon populations comprise 23 CUs: 2 Chinook, 3 chum, 3 coho, 3 pink, 2 river-type sockeye, 8 lake-type sockeye, and 2 steelhead CUs (Appendix 1). The initial process of data gathering, synthesis, outreach, and engagement to complete the initial assessments within the Nass Region was conducted from 2015 to 2019.

We worked with First Nations in the Nass Region to garner feedback on the Pacific Salmon Explorer approach and analyses through the Nisga’a-Canada-BC Nass Joint Technical Committee and the Gitanyow Fisheries Authority. In addition, in 2015 - 2016, we formed a Nass Technical Advisory Committee to engage with First Nations, DFO regional biologists and managers, and other salmon experts throughout the watershed.

Figure 5.3: Map of the Nass Region.

5.3.1 Population Data and Analytical Methods

As with the Skeena Region, many of the datasets necessary to understand the dynamics of salmon CUs in the Nass Region were historically compiled and stored through the North and Central Coast (NCC) Database [English et al. (2018); see Skeena Region]. However, in recent years, we have worked directly with the Nisga’a Lisims Government and LGL Limited staff to compile and synthesize CU-level information (English et al. 2023). For steelhead, data were sourced from English et al. (2023) (see our steelhead-specific Github repository for all raw steelhead population data compiled). Details regarding nuances to the data and analytical methods that are specific to the Nass Region are described below.

5.3.1.1 Spawner Surveys

Spawner survey data for streams in the Nass Region were sourced from DFO’s New Salmon Escapement Database (NuSEDS). For a description of the spawner survey indicator, see Overview of Population Indicators: Spawner Surveys. For steelhead, spawner survey data were provided directly from the Nisga’a Lisims Goverment Fish and Wildlife and LGL Limited (English et al. 2023).

5.3.1.2 Juvenile Surveys

Juvenile surveys for the Lower Nass coho CU was provided by Nisga’a Fish and Wildlife. For a description of the juvenile surveys indicator, see Overview of Population Indicators: Juvenile Surveys.

5.3.1.3 Hatchery Releases

Hatchery releases in the Nass Region for all species were provided by DFO (Brock Ramshaw, Salmonid Enhancement Program). Data on hatchery locations, release sites, and release numbers from the Freshwater Fisheries Society of BC are available through the Province of British Columbia’s BC Data Catalogue. Refer to Overview of Population Indicators: Hatchery Releases for details on data and analytical methods.

5.3.1.4 Spawner Abundance

Observed spawner abundance for CUs in the Nass Region is the sum of all spawner survey data as documented in NuSEDS, as described in Overview of Population Indicators: Spawner Abundance. Nass Region CU-level estimates of spawner abundance (run reconstructions) were sourced from English et al. (2023). Some CU-level estimated spawner abundance time series were developed according to the expansion factors described in the Skeena Region section.

In addition, CU-level estimates of spawner abundance for five Nass CUs are derived from additional spawner enumeration methods. Specifically, three salmon CUs (plus one steelhead CU) have mark-recapture programs operated by Nisga’a Fisheries and Wildlife (English et al. 2023).

5.3.1.5 Run Timing

Run timing data were compiled from a variety of sources detailed in Wilson and Peacock (In review), including the Gitwinksihlkw fish wheel and Coded-wire Tag recovery projects at Zolzap Creek and Kincolith River.

5.3.1.6 Catch & Run Size

Catch and run size, and subsequent exploitation rates for CUs in the Nass Region were calculated by LGL, Nisga’a Fish and Wildlife, and DFO from the Fisheries Operating System (FOS) and other DFO databases. These data were reported in English et al. (2023). For a description of catch and run size methods, see Overview of Population Indicators: Catch & Run Size.

5.3.1.7 Recruits-per-Spawner

Recruits-per-spawner data for CUs in the Nass Region were derived from the DFO age database and CU-level estimates of spawner abundance and catch and run size accessed from (English et al. 2023). For a description of recruits-per-spawner methods, see Overview of Population Indicators: Recruits-per-Spawner.

5.3.1.8 Biological Status

The biological status assessments for salmon CUs in the Nass Region currently reflect data that are current to 2022. For steelhead, spawner abundance data were provided by the Nisga’a Lisims Goverment Fish and Wildlife and LGL Limited and are current up to 2022 (English et al. 2023). As new data become available, we will update the analyses and results in this report and the Pacific Salmon Explorer. See Benchmarks for Assessing Biological Status and Decision Rules for Assessing Biological Status for more details on biological status assessment methods.

5.3.2 Habitat Data and Analytical Methods

Nuances regarding habitat pressure indicator data and analytical methods for the Nass Region are listed below. Refer to Population Status: Indicators & Benchmarks for information on habitat pressure indicators, benchmarks, and the analytical methods used to assess habitat status.

5.3.2.1 Spawning Zones of Influence

Methods for delineating Chinook CU spawning zones of influence (ZOIs) vary by region in accordance with the CU delineation approach used by DFO. In the Skeena, Nass, and Central Coast regions, Chinook CUs are defined using a more restrictive geographic representation, which resulted in fewer (or no) spawning locations occurring within the CU boundaries. As such, spawning ZOIs for each Chinook CU were delineated using the extent of all 1:20K FWA Assessment Watersheds that directly intersected with Nass Chinook CU boundaries.

5.4 Skeena Region

The Skeena River watershed, located along the north coast of BC, is the second-largest in the province, contains important tributaries, including the Babine, Kispiox, and Bulkley Rivers, and is one of the most productive river systems in BC. All five species of Pacific salmon spawn and rear in the lower and upper portions of the Skeena River Basin (Figure 5.4) within 66 CUs: 11 Chinook, 4 chum, , 4 coho, 5 pink, 2 river-type sockeye, 29 lake-type sockeye, and 11 steelhead (Appendix 1). The initial process of data gathering, synthesis, outreach, and engagement to complete the initial assessments for five salmon species within the Skeena Region was conducted over five years, from 2010 to 2014. Subsequent updates to those data have occurred regularly, and steelhead were added in 2023.

Figure 5.4: Map of the Skeena Region.

During the initial development of the Pacific Salmon Explorer for the Skeena, we formed a Skeena Technical Advisory Committee and engaged with First Nations, DFO, and other salmon experts throughout the watershed. Through the Technical Advisory Committee process, we received input and feedback from the Gitanyow Fisheries Authority, DFO, Office of the Wet’suwet’en, Lake Babine Nation, Gitxsan Watershed Authorities, Gitxaala First Nation, North Coast-Skeena First Nations Stewardship Society, SkeenaWild Conservation Trust, Bulkley Valley Research Centre, Suskwa Research, BC Ministry of Environment, and DFO.

5.4.1 Conservation Unit Changes

Based on feedback from the Skeena Technical Advisory Committee, we made several changes to the CU list, such that the CUs listed in the Pacific Salmon Explorer may differ from those provided by DFO. Specifically, we combined the Mcdonnell, Aldrich, and Dennis lake-type sockeye CUs into a single CU (Mcdonnell/Aldrich/Dennis) since the contribution of each of these lakes cannot be currently assessed from the estimated spawner abundance data. For the same reason, we combined the Morice and Atna lake-type sockeye CUs (Morice/Atna), and the Bulkley and Maxan (Bulkley/Maxan) lake-type sockeye CUs. Following updates by DFO, the Swan/Club CU was removed from the PSE in August 2024 and its spawner surveys and spawning location data was assigned to the Stephens CU. Similarly, the former Sicintine Chinook CU was removed with component populations assigned to the Upper Skeena Chinook CU (Winther et al. 2024).

We split the Babine lake-type sockeye CU into four CUs based on run-timing and enhancement. The wild portions of the CU are split into Babine/Onerka (early timing), Tahlo/Morrison (mid timing), and Nilkitkwa (late timing). The enhanced portion of the CU (originating from the Pinkut and Fulton spawning channels) is considered as the Babine (enhanced) CU.

For steelhead, we used CUs defined by Tautz et al. (2011) for steelhead in the Skeena watershed. No changes were made to the CUs defined in this publication.

5.4.2 Population Data and Analytical Methods

In the Skeena Region, PSF accessed data through three different sources, depending on species. For pink, chum. and coho, data was accessed via the North and Central Coast (NCC) Database (English et al. 2018). The NCC Database is a database originally produced by LGL Ltd., who synthesize datasets on spawner surveys, catch, exploitation rate, and age structure. LGL also includes generated datasets for CU-level estimates of spawner abundance, run size, and exploitation rate. For the most part, data in the NCC Database have been sourced by LGL from DFO’s New Salmon Escapement Database (NuSEDS), the Fisheries Operating System (FOS), and other DFO databases. For Chinook, data was sourced from Winther et al. (2024). For sockeye, data was sourced from DFO (Charmaine Carr-Harris, personal communication). For steelhead, there is no centralized public database for population data so these data were compiled from disparate sources, including from online databases, individual reports, and data custodians (see our steelhead-specific Github repository for all raw steelhead population data compiled). Details regarding nuances to the data and analytical methods specific to the Skeena Region are described below.

5.4.2.1 Spawner Surveys

Spawner survey data for streams in the Skeena Region were sourced from DFO’s New Salmon Escapement Database (NuSEDS). For a description of the spawner survey indicator, see the Overview of Biological Indicators: Spawner Surveys. For steelhead, spawner survey data for streams in the Skeena Region were compiled from regional data custodians at the Skeena Region Office of the Province of BC’s Fish and Wildlife Branch and from published reports, including from Baxter (1997), Mitchell (2000), Saimoto and Saimoto (2011), and Skeena Fisheries Branch (2019).

5.4.2.2 Juvenile Surveys

Juvenile abundance data for the Babine (enhanced), Babine/Onerka, Tahlo/Morrison, and Nilkitkwa lake-type sockeye CUs were available in Cox-Rogers (2012). Juvenile abundance estimates for the Gitanyow lake-type sockeye CU were available from Beblow et al. (2018). Juvenile abundance of the Slamgeesh lake-type sockeye CU was available from Fernando (2018) and previous reports. For steelhead, data were sourced for the Kispoix, Middle Skeena, Morice, and Skeena Coastal Summers CUs from David Bustard & Associates (1993) and Williamson (2002). For a description of the juvenile survey’s indicator, see Overview of Population Indicators: Juvenile Surveys.

5.4.2.3 Hatchery Releases

Hatchery releases in the Skeena Region for all species were provided by DFO (Brock Ramhsaw, DFO Salmonid Enhancement Program). For steelhead, Data on hatchery locations, release sites, and release numbers from the Freshwater Fisheries Society of BC are available through the Province of British Columbia’s BC Data Catalogue. Refer to Overview of Population Indicators: Hatchery Releases for details on data and analytical methods.

5.4.2.4 Spawner Abundance

Observed spawner abundance for CUs in the Skeena Region is the sum of all spawner survey data documented in NuSEDS, as described in Overview of Population Indicators: Spawner Abundance.

Skeena CU-level estimates of spawner abundance (run reconstructions) were sourced from the North and Central Coast (NCC) database for pink, chum and coho salmon. The quantity and quality of the estimated spawner abundance in NuSEDS varies by time period, region, and stream. Meanwhile, the observed spawner abundance data are not always representative of actual changes in abundance through time for a CU. As such, an “expansion procedure” is needed so that any changes in abundance through time are not confounded with changes in monitoring effort. Since 2008, PSF has worked with LGL Limited to generate Skeena (and Nass and Central Coast) CU-level estimated spawner abundance or run reconstructions in collaboration with DFO North Coast stock assessment staff (English et al. 2006, 2018; English 2012). Three expansion factors are used to generate estimated spawner abundance. The first expansion factor uses historical proportional contribution data to infill indicator streams not monitored in a given year. The second expansion factor expands the data from the monitored indicator streams so that the estimated spawner abundance is representative of the entire CU. The final expansion factor expands this number again for observer efficiency.

The expansion procedures, by necessity, make a number of simplifying assumptions. The first expansion factor assumes that the proportion of the overall CU that each indicator stream represents is constant through time. The second expansion factor assumes that indicator and non-indicator streams make up a constant contribution to the overall abundance of a CU. The final expansion factor assumes that observer efficiency is constant between years, CUs, methodologies (except for fences), and hydrological systems. For CUs in the Skeena Region (and for CUs in the Nass, Central Coast and Haida Gwaii Regions), we attempted to account for potential data quality issues associated with the final observer efficiency expansion factor (see Data Quality). However, these assumptions may potentially still incorporate uncertainty into our assessments of biological status in these Region’s CUs. These uncertainties result from spawner surveys being conducted using various methodologies and/or by different observers throughout time, which is not currently accounted for.

For Skeena Chinook, we used the estimated spawner abundance data reported in Winther et al. (2024). Estimated spawner abundance was available for six CUs, and was derived by expanding the proportion of Kitsumkalum River Chinook identified at the Tyee test fishery.

In contrast to Chinook, there has been more consistent distribution and quantity of monitoring effort for Skeena sockeye CUs dating back to 1960. Skeena sockeye data underwent a significant review and update in 2022 (Fisheries and Oceans Canada 2023). We were provided an update of the estimated spawner abundance data file by DFO (Charmain Carr-Harris, personal communication).

For steelhead, we did not apply expansion procedures to observed spawner abundance data to produce estimated spawner abundance. Instead, where spawner survey data approximate the CU-scale (i.e. counts or estimates are produced that are inclusive of all steelhead populations in the CU), we present these data as estimated spawner abundance. Data sources for these data include custodians at the Skeena Region Office of the Province of BC’s Fish and Wildlife Branch, Skeena Fisheries Branch (2019), and Saimoto and Saimoto (2011). For the case of the Bulkley and Morice CUs, estimates from Saimoto and Saimoto (2011) represent the total number of spawners returning to these two CUs combined and there is not precedence for estimating the proportion of spawners returning to each individual CU. We visualize these estimates as the estimated spawner abundance for both the Bulkley and Morice CUs (i.e. the same estimated spawner abundance data are visualized for the spawner abundance indicator for both CUs).The Tyee Test Fishery has operated at the mouth of the Skeena River since 1955 providing an aggregate-level index of spawner abundance for steelhead returning to the 10 summer-run CUs in the Skeena watershed. There are, however, currently no available data for escapement to specific CUs or populations based on Tyee Test Fishery monitoring.

5.4.2.5 Run Timing

Estimates of peak timing of river entry for the different sockeye CUs were estimated from DNA sampled from fish caught in the Tyee test fishery near the mouth of the Skeena River between 2000-2010 (Cox-Rogers 2012). The duration of the timing of river entry is assumed to have a bell-shaped curve (i.e. normal distribution), so the shape of the curves is defined by the mean and standard deviation of the available run timing data. However, in most instances, there is insufficient data to determine if a different distribution would better describe the shape of the curve. A normal distribution curve is likely a reasonable approximation for run timing in most cases if the run timing is unimodal (i.e. if there is a single peak in run timing). If the run timing is bi-modal (i.e. if there are two run timing groups), the assumption of spread is likely reasonable, but the peak may be misleading.

Note that these run timing curves were only used to estimate exploitation rates for Skeena sockeye CUs. A conservative assumption of relatively broad run timing (80-110 days) for each sockeye CU was used so that exploitation rates would not be sensitive to small shifts in fishery timing. For some CUs, run timing information is not available, and for some species, run timing is assumed to be the same for all CUs.

For six Chinook CUs, timing was estimated from Tyee test fishery data from 2009-2016, taken from Winther et al. (2024). Test fishery data were available for other years between 2000 and 2022, but often missed the start of the run and so we opted to use the period when the test fishery began operation in late-May, better capturing the start of Chinook migrations. For steelhead, run timing from the Tyee test fishery was taken from Beacham et al. (2012).

For other CUs, run timing data were estimated by DFO North Coast Staff. See Overview of Population Indicators: Run Timing for a description of the run timing indicator and methods.

5.4.2.6 Catch & Run Size

Catch and run size, and subsequent exploitation rates for CUs in the Skeena region were calculated by LGL and DFO from the Fisheries Operating System (FOS) and other DFO databases. We accessed these datasets for pink, chum and coho salmon via the North and Central Coast (NCC) Database, maintained by LGL Ltd. (English et al. 2018) and for sockeye following Fisheries and Oceans Canada (2023). For a description of catch and run size methods, see Overview of Population Indicators: Catch & Run Size.

5.4.2.7 Recruits-per-Spawner

Recruits-per-spawner data for CUs in the Skeena Region were derived from the DFO age database and CU-level estimates of spawner abundance and catch and run size, accessed from the NCC Database (English et al. 2018) for pink, chum, and coho salmon. Sockeye salmon data was from Fisheries and Oceans Canada (2023) and Chinook salmon data was from Winther et al. (2024). For a description of recruits-per-spawner methods, see Overview of Population Indicators: Recruits-per-Spawner.

5.4.2.8 Biological Status

The biological status assessments for CUs in the Skeena Region reflect data sourced from the NCC database and are current up to 2022 for sockeye, 2020 for Chinook and 2019 for other salmon species. For steelhead, data was sourced from data custodians at the Skeena Region Office of the Province of BC’s Fish and Wildlife Branch and from Skeena Fisheries Branch (2019) and are current up to 2022. The original approach and results for Skeena biological status assessments are described in Korman and English (2013). As new data become available, we will update the analyses and results in this report and the Pacific Salmon Explorer. See Benchmarks for Assessing Biological Status and Decision Rules for Assessing Biological Status for more details on biological status assessment methods

5.4.3 Habitat Data and Analytical Methods

Nuances regarding habitat pressure indicator data and analytical methods for the Skeena Region are listed below. Refer to Indicators and Benchmarks for Assessing Habitat Status for information on habitat pressure indicators, benchmarks, and the analytical methods used to assess habitat status.

5.4.3.1 Spawning Zones of Influence

Methods for delineating Chinook CU spawning zones of influence (ZOIs) vary by region in accordance with the CU delineation approach used by DFO. In the Skeena, Nass, and Central Coast regions, Chinook CUs are defined using a more restrictive geographic representation, which resulted in fewer (or no) spawning locations occurring within the CU boundaries. As such, spawning ZOIs for each Chinook CU were delineated using the extent of all 1:20K FWA Assessment Watersheds that directly intersected with Skeena Chinook CU boundaries.

5.5 Central Coast Region

The Central Coast Region supports diverse populations of all five Pacific salmon species and steelhead (Figure 5.5). These salmon populations comprise 117 CUs: 7 Chinook, 9 chum, 7 coho, 5 pink, 3 river-type sockeye, 82 lake-type sockeye, and 4 steelhead CUs (Appendix 1).

While this area is less easily defined than an extensive river system such as the Skeena or Fraser Regions, we could determine the Central Coast study area using three criteria. First, the intent was to include the full geographic extent of most CUs on the Central Coast Appendix 1. Second, we considered the adjacency of other Regions within the Pacific Salmon Explorer to minimize overlap between study areas. Third, we considered major drainage patterns as represented in BC’s Freshwater Atlas (FWA) 1:20K Watershed Groups (MOE, 2017a). According to these criteria, the resulting Central Coast Region on the Pacific Salmon Explorer encompasses 54,813 km\(^2\) from Smith and Rivers Inlets in the south, and Douglas Channel and Banks, McCauley, and Pitt Islands in the north (Figure 5.5). The process of data gathering, synthesis, outreach, and engagement to complete the initial assessments within the Central Coast Region was conducted over two years, from 2016 to 2018.

For the Central Coast Region, we worked with two technical committees (one for the north portion and one for the south portion of the region) to garner feedback on the Pacific Salmon Explorer approach and analyses. These Technical committees were comprised of First Nations, DFO regional biologists, managers, and other salmon experts to garner feedback on the Pacific Salmon Explorer approach and analyses. We received feedback from the Central Coast Indigenous Resource Alliance and the Nuxalk, Kitasoo/Xai’Xais, Heiltsuk, Wuikinuxv Gitxaala, and Haisla First Nations.

5.5.1 Conservation Unit Changes

As part of the Technical Committee review process, we removed two CUs (Whalen Lake and Owikeno-Late sockeye (lake-type) CUs). The Whalen Lake sockeye CU is included in (Holtby and Ciruna 2007), but long-time Charter Patrolman and Technical Committee member, Stan Hutchings, recommended removing it from the list of CUs. An impassable waterfall prevents sockeye from accessing Whalen Lake, which is the spawning and rearing lake for this CU. As such, we removed this CU from the project. The Owikeno-Late sockeye CU is not listed in (Holtby and Ciruna 2007) but was provisionally designated as a CU by Blair Holtby in 2008. However, a Technical Committee member from Wuikinuxv advised us that this CU is not distinguishable from other sockeye CUs in the lake. Furthermore, this CU was not included on the most recent list of CUs published on the Government of Canada’s Open Data portal. Given that it was not in the most current list of CUs, it lacks baseline data, and we could not find any documentation about its creation. Therefore, we removed this CU from the project.

For steelhead in the Central Coast Region, we used CUs defined in Parkinson et al. (2005). Through our work and conversations with the Steelhead Technical Working Group, we identified a key issue with the spatial boundaries for some coastal steelhead CUs for groups of winter-run populations, including the North Coast Winter CU in the Central Coast Region. One of the key distinguishing features among steelhead CUs is run timing. The CU boundaries for this winter-run CU did not include watersheds that contain both winter-run and coastal summer-run populations of steelhead. These watersheds were only included in the corresponding coastal summer-run CU (in this case, the North Coast Summer CU). To address this issue in a standardized way for all CUs with this issue, we expanded the CU boundaries for the winter-run CUs to include the entirety of watersheds in the corresponding summer-run CU. In this case, resulting in an overlapping region between the North Coast Winter and North Coast Summer CUs where steelhead from multiple CUs spawn. This approach did not capture watershed-specific nuances in the distribution of winter- and summer-run steelhead populations, which are often not documented. However, these changes to the North Coast Winter CU ensure the CU is not missing key watersheds.

Figure 5.5: Map of the Central Coast Region.

5.5.2 Population Data and Analytical Methods

There are several nuances to the data sources and analytical methods specific to the Central Coast Region. These nuances are listed below. For steelhead in general, there is no centralized public database for population data so these data were compiled from disparate sources, including from online databases, individual reports, and data custodians (see our steelhead-specific Github repository for all raw steelhead population data compiled).

5.5.2.1 Spawner Surveys

Spawner survey data for streams in the Central Coast were sourced from DFO’s New Salmon Escapement Database (NuSEDS). For a description of the spawner survey indicator, see Overview of Population Indicators: Spawner Surveys. For steelhead, spawner survey data were sourced from English et al. (1999a), Peard (2017), and Ptolemy et al. (2006).

5.5.2.2 Juvenile Surveys

Juvenile survey data for the Hecate Lowlands (even) pink, Hecate Strait-Lowlands (odd) pink, Hecate Strait Mainland coho, Hecate Lowlands chum, Roderick sockeye, and Mary Cove Creek sockeye CUs within Kitasoo/Xai’xais territory were provided by Larry Greba (Kitasoo/Xai’xais Development Corporation). For a description of the juvenile survey’s indicator, see Overview of Population Indicators: Juvenile Surveys.

5.5.2.3 Hatchery Releases

Hatchery releases in the Central Coast Region for all species were provided by DFO (Brock Ramshaw, Salmonid Enhancement Program). Data on hatchery locations, release sites, and release numbers from the Freshwater Fisheries Society of BC are available through the Province of British Columbia’s BC Data Catalogue. Refer to Overview of Population Indicators: Hatchery Releases for details on data and analytical methods.

5.5.2.4 Spawner Abundance

Observed spawner abundance for CUs in the Central Coast Region is the sum of all spawner survey data documented in NuSEDS, as described in Overview of Population Indicators: Spawner Abundance. For steelhead, observed spawner data are summed spawner survey data sourced from English et al. (1999a), Peard (2017), and Ptolemy et al. (2006).

Central Coast CU-level estimates of spawner abundance (run reconstructions) were updated by PSF via the North and Central Coast (NCC) database. Central Coast CU-level estimated spawner abundance time series were developed for the NCC database according to the expansion factors described in the Skeena Region section above.

5.5.2.5 Run Timing

Run timing information for many Central Coast salmon CUs was sourced from Goruk and Winther (1992). We relied on a several reports describing the life-history of steelhead in the region Nelson et al. (1998). Further details on the compilation of run timing data are provided by Wilson and Peacock (In review). See Overview of Population Indicators: Run Timing for a description of the run timing indicator and methods.

5.5.2.6 Catch & Run Size

Catch and run size, and subsequent exploitation rates for CUs on the Central Coast were calculated by DFO and LGL from data in the Fisheries Operating System (FOS) and other DFO databases. Similar to our work in the Skeena and Nass, we accessed most of these datasets via the North and Central Coast (NCC) Database, maintained by LGL Ltd, and updated by PSF for 2018-202. (English et al. 2018). For a description of catch and run size methods, see Overview of Population Indicators: Catch & Run Size.

5.5.2.7 Recruits-per-Spawner

Recruits-per-spawner data for CUs on the Central Coast were derived from the DFO age database and CU-level estimates of spawner abundance and catch and run size accessed from the NCC Database (English et al. 2018). These data were updated by PSF to cover the years 2018-2021 For a description of recruits-per-spawner methods, see Overview of Population Indicators: Recruits-per-Spawner.

5.5.2.8 Biological Status

The biological status assessments for CUs in the Central Coast Region reflect data updated by PSF via the NCC database and are current up to 2021. As new data become available, we will update the analyses and results in this report and the Pacific Salmon Explorer. See Benchmarks for Assessing Biological Status and Decision Rules for Assessing Biological Status for more details on biological status assessment methods.

5.5.3 Habitat Data and Analytical Methods

Nuances regarding habitat pressure indicator data and analytical methods for the Central Coast Region are listed below. Refer to Habitat Status: Indicators & Benchmarks for information on habitat pressure indicators, benchmarks, and the analytical methods used to assess habitat status.

5.5.3.1 Trans-regional Conservation Units

The pink (odd-year) Homathko-Klinaklini-Smith-Rivers-Bella Coola-Dean CU spans the boundary between the Central Coast and Vancouver Island & Mainland Inlets Regions.

5.5.3.2 Spawning Zones of Influence

Methods for delineating Chinook CU spawning zones of influence (ZOIs) vary by region in accordance with the CU delineation approach used by DFO. In the Skeena, Nass, and Central Coast regions, Chinook CUs are defined using a more restrictive geographic representation, which resulted in fewer (or no) spawning locations occurring within the CU boundaries. As such, spawning ZOIs for each Chinook CU were delineated using the extent of all 1:20K FWA Assessment Watersheds that directly intersected with Central Chinook CU boundaries.

5.5.3.3 Additional Spawning Habitat Information Sources

In addition to the spawning habitat information we acquired from the Fisheries Information Summary System (FISS) database and local knowledge derived through expert elicitation, we received additional spawning habitat information from a technical report provided by Diana Chan and Mike Reid (Fisheries, Heiltsuk First Nation) (Temple 2007).

5.6 Fraser Region

The Fraser River watershed and adjacent coastal watersheds (collectively, the “Fraser Region”; (Figure 5.6)) support an incredible diversity of salmon with 67 CUs. There are five CUs in the Fraser Region designated as extinct by DFO, two of which have been reintroduced and are new de novo CUs Appendix 1. By species, the Fraser Region supports 19 Chinook, 1 chum, 8 coho, 1 pink, 2 river-type sockeye, 30 lake-type sockeye, and 6 steelhead CUs (Appendix 1).

DFO officially uses the European designation to indicate age class for CUs within the Fraser Region. However, in the Pacific Salmon Explorer and this report, we use the Gilbert-Rich designation, which is more familiar to most users. We made this decision based on feedback from the Population Science Advisory Committee and other local users in the Region. The process of data gathering, synthesis, outreach, and engagement to complete the initial assessments within the Fraser Region was conducted over two years, from the spring of 2018 to 2020.

Figure 5.6: Map of the Fraser Region.

Within the Fraser Region, we worked with First Nations, DFO regional biologists and managers, and other salmon experts to garner feedback on the Pacific Salmon Explorer approach and analyses through four sub-regions according to geographic and social groupings: Lower Fraser, Middle Fraser - Mainstem, Middle Fraser - Thompson, and Upper Fraser. Through a series of introductory and Technical Meetings, we received feedback from First Nation aggregate organizations and individual First Nations across those areas, including the Lower Fraser Fisheries Alliance (LFFA) and Lower Fraser First Nations, Secwepemc Fisheries Commission (SFC), and SFC First Nations, Scw’exmx Tribal Council (STC), St’at’imc Chiefs Council (SCC) and member Nations, Nlaka’pamux Nation Tribal Council (NNTC) and NNTC First Nations, Okanagan Nation Alliance (ONA), and the Upper Fraser Fisheries Conservation Alliance including members of the Tsilhqot’in National Government, Carrier-Sekani Tribal Council (CSTC), North Shuswap Tribal Council (NSTC), and Carrier-Chilcotin Tribal Council (CCTC).

5.6.1 Conservation Unit Changes

For sockeye, we made minor revisions to the CU list for the Fraser region. The Adams and Momich Lakes - Early Summer CU was removed from the CU list and replaced by two separate CUs for Adams - Early Summer and Momich - Early Summer. This is consistent with the separate assessments of these two CUs by COSEWIC (2021).

For steelhead in the Fraser Region, we used CUs defined in Parkinson et al. (2005). Through our work and conversations with the Steelhead Technical Working Group, we identified a key issue with the spatial boundaries for some coastal steelhead CUs for groups of winter-run populations, including the Lower Fraser Winter CU in the Fraser Region. One of the key distinguishing features among steelhead CUs is run timing. The CU boundaries for this winter-run CU did not include watersheds that contain both winter-run and coastal summer-run populations of steelhead. These watersheds were only included in the corresponding coastal summer-run CU (in this case, the Lower Fraser Summer CU). To address this issue in a standardized way for all CUs with this issue, we expanded the CU boundaries for the winter-run CUs to include the entirety of watersheds in the corresponding summer-run CU. In this case, resulting in an overlapping region between the Lower Fraser Winter and Lower Fraser Summer CUs where steelhead from multiple CUs spawn. This approach did not capture watershed-specific nuances in the distribution of winter- and summer-run steelhead populations, which are often not documented. However, these changes to the Lower Fraser Winter CU ensure the CU is not missing key watersheds.

5.6.2 Population Data and Analytical Methods

In the Fraser Region, we accessed datasets for biological status and indicators directly from DFO and PSC staff. Additional data was sourced from NuSEDS and FOS. For steelhead, there is no centralized public database for population data so these data were compiled from disparate sources, including from online databases, individual reports, and data custodians (see our steelhead-specific Github repository for all raw steelhead population data compiled). Details on specific data sources and analytical methods for the Fraser Region are described below.

5.6.2.1 Spawner Surveys

Spawner survey data for streams in the Fraser Region were sourced from DFO’s New Salmon Escapement Database (NuSEDS). For a description of the spawner survey indicator, see Overview of Population Indicators: Spawner Surveys. For steelhead, spawner survey data were sourced from data custodians at the Thompson Regional Office of the Province of BC’s Fish and Wildlife Branch (Rob Bison, Fisheries Stock Assessment Biologist) as well as from Beere (2016), Buchanan et al. (2020), Hagen (2001), and White et al. (2021).

5.6.2.2 Juvenile Surveys

In the Fraser Region, we accessed juvenile survey data for two sockeye CUs: Cultus Lake (provided by Mike Bradford, DFO Ecosystem Sciences Division, Freshwater Ecosystems) and Chilko-Summer (provided by Mike Hawkshaw, DFO Stock Assessment, Sockeye & Pink Analytical Program). juvenile abundance data are collected at Cultus Lake, within the Lower Fraser River, at a counting fence on Sweltzer Creek, the downstream outlet of the lake. DFO has been monitoring juvenile outmigration at Sweltzer Creek since 1926. Similarly, juvenile abundance at Chilko Lake has also been monitored by DFO in collaboration with local First Nations fisheries technicians at a juvenile counting fence each spring since 1949. For steelhead, juvenile survey data were sourced from Buchanan et al. (2020) and Decker et al. (2015). For a description of the juvenile survey indicator, see Overview of Population Indicators: Juvenile Surveys.

5.6.2.3 Hatchery Releases

Hatchery releases in the Fraser Region for all species were provided by DFO (Brock Ramshaw, Salmonid Enhancement Program). Data on hatchery locations, release sites, and release numbers from the Freshwater Fisheries Society of BC are available through the Province of British Columbia’s BC Data Catalogue. Refer to Overview of Population Indicators: Hatchery Releases for details on data and analytical methods.

5.6.2.4 Spawner Abundance

In the Fraser Region, observed spawner abundance is the sum of all spawner survey data documented in NuSEDS, as described in Overview of Population Indicators: Spawner Abundance. For steelhead spawner abundance data were sourced from data custodians at the Thompson Regional Office of the Province of BC’s Fish and Wildlife Branch as well as from Beere (2016), Buchanan et al. (2020), Hagen (2001), and White et al. (2021).

Estimated spawner abundance in Fraser Region is not available from a centralized database. Estimates of spawner abundance were acquired from specific DFO and PSC biologists with the following species-specific nuances. For sockeye, we visualize Effective Total Spawners, which reflects an estimate provided by DFO of successfully spawned female and male sockeye, accounting for pre-spawn mortality (during migration; provided by Fiona Martens, Pacific Salmon Commission). For pink salmon, we visualize a dataset acquired from the Pacific Salmon Commission (Fiona Martens, Pacific Salmon Commission). This dataset has some uncertainty as the enumeration program for pink salmon escapement in the Fraser River has varied over time. Specifically, DFO stopped conducting spawner survey programs for pink salmon in 2001; therefore, estimates from 2003-2007 are based on test fishing programs in the marine approach area before river entry and within the lower Fraser River. Estimates from 2009 onward are based on the hydroacoustics program run by the Pacific Salmon Commission at Mission. For Chinook, estimated spawner abundance was generated through the Southern BC Chinook Technical Working Group (Brown et al. 2020).

In contrast to estimated spawner abundance values for other species and areas, values for Fraser Chinook are only a subset of those available for the entire CU. These values are based on the most intensively monitored streams (i.e. there is no expansion made so that the estimated value represents CU as the whole). The year at which each estimate spawner abundance time series for Chinook also varies based on the availability and quality of data, with the start year of the time series determined by expert opinion (Brown et al. 2020). For coho, estimated spawner abundance was sourced from(Korman et al. 2019). There are no CU-level estimates of spawner abundance for chum salmon in the Fraser River.

For steelhead, estimates for the total number of steelhead returning to the Thompson River watershed are estimated by the Thompson Regional Office of the Province of BC’s Fish and Wildlife Branch. The scale of these estimates aligns with the Thompson Summer CU, so these data are presented as the estimated spawner abundance for this CU. Estimates of the total number of steelhead returning to the Chilcotin River watershed are also estimated by the Thompson Regional Office of the Province of BC’s Fish and Wildlife Branch. The scale of these estimates approximate the scale of the Mid Fraser Summer CU, so these data are presented as the estimated spawner abundance for this CU. Both these datasets were provided directly from the Province of BC’s Thompson Regional Office (Rob Bison, Fisheries Stock Assessment Biologist), but PSF has not identified a publication that describes how these estimate are generated from spawner survey data.

5.6.2.5 Run Timing

Run timing estimates were compiled by Wilson and Peacock (In review). Data were provided for some Fraser sockeye CUs (Fiona Martens and Merran Hague, Pacific Salmon Commission). The median estimate date and spread represent the run timing date through DFO Area 20 for each management unit from 1980 to 2017. Each CU within a management unit was assumed to have the same run timing. For Fraser pink salmon, timing information from the hydroacoustic monitoring at Mission was provided by the Pacific Salmon Commission on request.

Other CU run timing information came from Parken et al. (2008) for Chinook and Irvine et al. (n.d.) for coho. Brittany Jenewin (DFO, pers. comm) shared raw data on chum salmon catch in the Albion test fishery.

For steelhead, life-history information was compiled from older reports including Withler (1966) and Caverly (1978). Data compilation and sources are detailed in Wilson and Peacock (In review). See Overview of Population Indicators: Run Timing for a description of the run timing indicator and methods.

5.6.2.6 Catch & Run Size

Catch and run size data were provided for pink and sockeye (Fiona Martens, Pacific Salmon Commission) in the Fraser Region. For pink, catch data was separated between US and Canadian fisheries from 2011-2023. Prior to 2011, we show the combined US and Canadian catch data. For Fraser sockeye catch and run size data, we worked with the Pacific Salmon Commission to institute a number of region-specific visualization exceptions. Specifically, we have introduced two Fraser sockeye-specific parameters: Run Size Adjustment (RSA) and In Season Run Size. For Fraser sockeye CUs, RSA accounts for in-river mortality, and/or positive or negative adjustment to available spawner and catch estimates; it is based on a post-season evaluation of risk factors influencing the probability of successful migration and an evaluation of biases for estimates of spawning escapements and catch (and other ‘miscellaneous’ biases). The RSA data begins in 2003 (see further details below). Prior to 2009, the RSA estimates have been based on differences between estimates (DBEs), i.e. differences between the number of salmon observed at Mission minus upstream catches and the spawning ground estimates. The process to determine the RSA is expert-led and conducted annually in the post-season to evaluate estimates of en-route mortality and to estimate biases in spawning escapement and catch. The RSA process requires various assessments and detailed discussions among participants. While efforts are being made to execute this process more promptly, the RSA process will delay the availability of run size estimates by at least one or potentially more years. In addition to the RSA process, there may be other reasons why the derivation of run size estimates for Fraser River sockeye salmon are delayed e.g. delay in receiving catch reports.

The in-season run size is a preliminary estimate based on in-season data until post-season spawner, catch, and run size adjustment estimates are available. These preliminary estimates of run size are based on hydroacoustic estimates of fish passage collected at Mission plus seaward catches.

For Fraser River sockeye, exploitation rates are also provided by Management Group, as CU-specific exploitation rates are not considered reliable, especially when abundances are low. For a general description of catch and run size methods, see Overview of Population Indicators: Catch & Run Size.

5.6.2.7 Recruits-per-Spawner

Recruits-per-spawner data were derived by DFO and PSC and provided for pink (Fiona Martens, Pacific Salmon Commission) and sockeye (Fiona Martens, Pacific Salmon Commission) in the Fraser Region. For steelhead, recruits-per-spawner data for the Thompson Summer and Mid Fraser Summer CUs were sourced from Committee on the Status of Endangered Wildlife in Canada (2020). For a description of recruits-per-spawner methods, see Overview of Population Indicators: Recruits-per-Spawner.

5.6.2.8 Biological Status

Nuances regarding biological status assessments for Fraser CUs are listed below. See Benchmarks for Assessing Biological Status and Decision Rules for Assessing Biological Status for more details on biological status assessment methods.

5.6.2.9 Fraser sockeye with cyclic dominance

For some sockeye CUs, annual cycle lines over time fluctuate in abundance by many orders of magnitude in relatively predictable patterns over a 4-year cycle. These patterns termed “cyclic dominance,” are characterized by one dominant cycle line that is very abundant, one that is sub-dominant and of moderate abundance, and two that have very low abundance. Delayed density-dependent mortality (i.e. interactions between cycle lines, which cause the survival of year-classes that follow the most abundant year to be reduced) is believed to be an important contributing factor to these large variations in abundance among brood lines. However, the exact operating mechanism remains unclear. For some CUs, brood line dominance has shifted over time, i.e. the same brood year is not consistently the dominant brood line over the entire modern time series. While cyclic dominance may be a factor in many sockeye CUs, it has only been explicitly documented for six sockeye CUs within the Fraser Region. Consequently, this phenomenon is only a consideration for our work on the Pacific Salmon Explorer for the Fraser Region. For these six cyclic CUs, we only visualize biological status as assessed by DFO and reported in the most recent Wild Salmon Policy report (DFO, 2018; see Decision Rules for Assessing Biological Status). The reason for this is due to the complexity of their life history and the resulting challenges with applying our standardized approach to assessing biological status using either spawner-recruitment or percentile benchmarks. The WSP and COSEWIC approaches apply these CUs because they apply multiple metrics and expert judgment to assess status.

5.6.3 Habitat Data and Analytical Methods

Nuances regarding habitat pressure indicator data and analytical methods for the Fraser Region are listed below. Refer to Habitat Status: Indicators & Benchmarks for information on habitat pressure indicators, benchmarks, and the analytical methods used to assess habitat status.

5.6.3.1 Spawning Zones of Influence

Methods for delineating Chinook CU spawning zones of influence (ZOIs) vary by region in accordance with the CU delineation approach used by DFO. In the Fraser and Vancouver Island and Mainland Inlet regions, Chinook CUs are geographically more broadly defined, which means that the methods employed for determining pink, chum, and coho spawning ZOIs were also applicable to Chinook CUs. The localized spawning ZOI for each Fraser Chinook CU was delineated by capturing the extent of all 1:20K FWA assessment watersheds that directly intersect with known spawning locations for Chinook.

5.7 Vancouver Island & Mainland Inlets

Vancouver Island & Mainland Inlets on the Pacific Salmon Explorer includes 93 distinct CUs, including all five species of Pacific salmon and steelhead. By species, the Region supports 14 Chinook, 9 chum, 10 coho, 10 pink, 4 river-type sockeye, 40 lake-type sockeye, and 6 steelhead CUs (Appendix 1).

We defined the Vancouver Island & Mainland Inlets Region according to similar criteria used on the Central Coast: geographic proximity to other Regions within the Pacific Salmon Explorer, geographic extent of CUs mainly contained within the Region and FWA Watershed Groups. The resulting Vancouver Island & Mainland Inlets Region (Figure 5.7) encompasses 76,411 km\(^2\) across Vancouver Island and the adjacent mainland fjords and inlets, from Burrard Inlet and Howe Sound in the south to Smith Inlet and the northern Broughton Archipelago in the north. The process of data gathering, synthesis, outreach, and engagement to complete the initial assessments within the Vancouver Island & Mainland Inlets Region was conducted over two years, from the spring of 2018 to 2020.

For the Vancouver Island & Mainland Inlet Region, we engaged with First Nations, DFO regional biologists and managers, and other salmon experts who provided feedback on the development of the Pacific Salmon Explorer through several localized Technical Meetings. The make-up of stakeholders at these Technical Meetings was based on various geographic and social groupings present across the region. Through the Technical Meeting and engagement process, we received feedback from First Nation aggregate organizations and individual First Nations across the Region, including the Island Marine Aquatic Working Group (IMAWG), A-Tlegay Fisheries Society and member Nations, Nuu-chah-nulth Tribal Council, and Nuu-chah-nulth First Nations, Maa-nulth Treaty Society and member Nations, Q’ul-lhanumutsun Aquatic Resources Society and Cowichan Tribes First Nation, Broughton Aquaculture Transition Initiative and the Namgis First Nation, Musgamagw Dzawada’enuxw Fisheries Group, the Quatsino First Nation, and Kwakiutl First Nation.

5.7.1 Conservation Unit Changes

The Sakinaw sockeye CU was declared extinct in the wild by DFO as of 2009 (Fisheries and Oceans Canada (DFO) 2018). However, there is still a population from a captive broodstock program maintaining a hatchery-derived population in Sakinaw Lake. However, since this CU was immediately reintroduced from broodstock from the same CU, it does not meet the criteria for being declared de novo (Wade et al. 2019).

For steelhead in the Vancouver Island & Mainland Inlet Region, we used CUs defined in Parkinson et al. (2005). Through our work and conversations with the Steelhead Technical Working Group, we identified a key issue with the spatial boundaries for some coastal steelhead CUs for groups of winter-run populations, including the West Coast Vancouver Island Winter, East Coast Vancouver Island Winter, and South Coast Winter CUs in the Vancouver Island & Mainland Inlet Region. One of the key distinguishing features among steelhead CUs is run timing. The CU boundaries for this winter-run CU did not include watersheds that contain both winter-run and coastal summer-run populations of steelhead. These watersheds were only included in the corresponding coastal summer-run CU (in this case, the West Coast Vancouver Island Summer, East Coast Vancouver Island Summer, and South Coast Summer CUs). To address this issue in a standardized way for all CUs with this issue, we expanded the CU boundaries for the winter-run CUs to include the entirety of watersheds in the corresponding summer-run CU. In this case, resulting in an overlapping region between the West Coast Vancouver Island Winter and West Coast Vancouver Island Summer CUs, the East Coast Vancouver Island Winter and East Coast Vancouver Island Summer CUs, and the South Coast Winter and South Coast Summer CUs, where steelhead from both CUs spawn. This approach did not capture watershed-specific nuances in the distribution of winter- and summer-run steelhead populations, which are often not documented. However, these changes to the West Coast Vancouver Island Winter, East Coast Vancouver Island Winter, and South Coast Winter CUs ensure these CUs is not missing key watersheds.

Figure 5.7: Map of the Vancouver Island & Mainland Inlets Region.

5.7.2 Population Data and Analytical Methods

In the Vancouver Island & Mainland Inlets Region, we directly accessed datasets for biological indicators from DFO staff. Additional data was sourced from NuSEDS and FOS. For steelhead, there is no centralized public database for population data so these data were compiled from disparate sources, including from online databases, individual reports, and data custodians (see our steelhead-specific Github repository for all raw steelhead population data compiled). Details on specific data sources and analytical methods for the Vancouver Island & Mainland Inlets Region are described below.

5.7.2.1 Spawner Surveys

Spawner survey data for streams in the Vancouver Island & Mainland Inlets Region Region were sourced from DFO’s New Salmon Escapement Database (NuSEDS). For steelhead, spawner survey were sourced from the Province of BC’s EcoCat, Korman and Schick (2019), and Mcculloch (2020). For a description of the spawner survey indicator, see Overview of Population Indicators: Spawner Surveys.

5.7.2.2 Juvenile Surveys

We acquired multiple sources’ juvenile survey data for several CUs in the Vancouver Island & Mainland Inlets Region. Juvenile survey data for streams within the East Vancouver Island-Georgia Strait coho CU were provided by Jim Meldrum (A-Tlegay Fisheries Society) and Karalea Cantera (DFO, Fish and Fish Habitat Protection Program). Juvenile survey data for streams within the Georgia Strait chum, East Vancouver Island-North (Fall 0.x), Chinook, and Georgia Strait pink (odd) CUs were provided by Jim Meldrum (A-Tlegay Fisheries Society). Juvenile survey data for streams within the West Vancouver Island-South (Fall 0.x) Chinook CU were provided by Bob Bocking (Maa-nulth Treaty Society) and Jared Dick (Nuu-chah-nulth Tribal Council). Juvenile survey data for streams within the West Vancouver Island coho CU were provided by Roger Dunlop (Nuu-chah-nulth Tribal Council), Karalea Cantera (DFO, Fish and Fish Habitat Protection Program), and sourced from Wade and Irvine (2018; DFO). Juvenile survey data for the Great Central Lake sockeye, Sproat Lake sockeye), and Henderson Lake sockeye CUs were provided by Graham Murrell (Nuu-chah-nulth Tribal Council). Juvenile survey data for the Nahwitti Lowland coho CU were provided by Trevor Davies (Provincial Ministry of Forests, Lands, Natural Resource Operations & Rural Development) and sourced from Wade and Irvine (2018). Juvenile survey data for streams within the East Vancouver Island-Georgia Strait coho and Georgia Strait Mainland coho CUs were provided by Karalea Cantera (DFO, Fish and Fish Habitat Protection Program) and sourced from Wade and Irvine (2018). Juvenile survey data for the Sakinaw Lake sockeye CU were provided by Karalea Cantera (DFO, Fish and Fish Habitat Protection Program). Juvenile surveye data for streams within the Juan de Fuca-Pachena coho CU were sourced from Wade and Irvine (2018). For steelhead, juvenile survey data were sourced from For steelhead, data used to derive estimated spawner abundance for was sourced from the Province of BC’s EcoCat, Korman and Schick (2019), and Mcculloch (2020). For a description of the juvenile survey indicator, see Overview of Population Indicators: Juvenile Surveys.

5.7.2.3 Hatchery Releases

Hatchery releases in the Vancouver Island & Mainland Inlets Region for all species were provided by DFO (Brock Ramshaw, Salmonid Enhancement Program). Data on hatchery locations, release sites, and release numbers from the Freshwater Fisheries Society of BC are available through the BC Data Catalogue. Refer to Overview of Population Indicators: Hatchery Releases for details on data and analytical methods.

5.7.2.4 Spawner Abundance

In the Vancouver Island & Mainland Inlets Region, observed spawner abundance is the sum of all spawner survey data documented in NuSEDS, as described in Overview of Population Indicators: Spawner Abundance. For steelhead, spawner survey were sourced from the Province of BC’s EcoCat, Korman and Schick (2019), and Mcculloch (2020).

Estimated spawner abundance in the Vancouver Island & Mainland Inlets Region is not available from a centralized database. Thus, estimates of spawner abundance were acquired from specific DFO biologists. For sockeye, estimated spawner abundance for Sproat and Great Central CUs was provided by Dawn Lewis (DFO Stock Assessment). The Nimpkish CU was provided by Pieter van Will (DFO Stock Assessment). For pink salmon, we visualize a dataset acquired from DFO (Pieter van Will). For Chinook, estimated spawner abundance was generated through the Southern BC Chinook Working Group (Brown et al. 2020).

In contrast to estimated spawner abundance values for other species and areas, Vancouver Island & Mainland Inlets Chinook values are only a subset of the entire CU. These subset values are based on the most intensively monitored streams (i.e. there is no expansion made so that the estimated value represents the whole CU). The year at which each estimate spawner abundance time series for Chinook also varies based on the availability and quality of data, with the start year of the time series determined by expert opinion (Brown et al. 2020). For chum, estimated spawner abundance was provided by Diana Dobson (DFO Stock Assessment) based on Holt et al. (2018) data. There are no CU-level estimates of spawner abundance for coho salmon in the Vancouver Island & Mainland Inlets Region. Thus, biological status for coho is data deficient for this Region.

For steelhead, there are instances where long timeseries (i.e., spanning at least 20 years) of spawner survey data are available for some, but not all streams within a CU. If we assume that the sum of spawners observed in these streams is a reasonable indicator of the relative abundance of the overall CU through time, then we can use these streams as an index of spawner abundance for the CU. In these cases, all available spawner counts or estimates in a CU are summed for each year to provide a historical timeseries of the observed spawner abundance for the CU. We account for years where one or more of the streams were not monitored by infilling data for those years based on the average proportional contribution from a given stream over the whole time series (i.e. the average proportion of total spawners typically from this stream). The resulting timeseries is then presented as the estimated spawner abundance timeseries. This protocol was applied to generate the estimated spawner abundance timeseries presented for the East Vancouver Island Winter, West Vancouver Island Summer, and East Vancouver Island Summer CUs. Data used to derive these indices of estimated spawner abundance for these CUs was sourced from the Province of BC’s EcoCat and Mcculloch (2020). This approach was endorsed by PSF’s Steelhead Technical Working Group and the Province of BC’s West Coast Region Fisheries Biologist (Mike McCulloch) because there is observed synchrony in trends among steelhead populations within the same CUs on Vancouver Island.

5.7.2.5 Run Timing

Run timing data were compiled from a variety of sources detailed in Wilson and Peacock (In review). See Overview of Population Indicators: Run Timing for a description of the run timing indicator and methods.

5.7.2.6 Catch & Run Size

Catch and run size data were provided for chum (Diana Dobson, DFO Stock Assessment), pink (Pieter van Will, DFO Stock Assessment), and sockeye (Diana Dobson and Pieter van Will, DFO Stock Assessment) in the Vancouver Island & Mainland Inlets Region. For a general description of catch and run size methods, see Overview of Population Indicators: Catch & Run Size.

5.7.2.7 Recruits-per-Spawner

Recruits-per-spawner data were derived by DFO and provided for chum (Diana Dobson, DFO Stock Assessment), pink (Pieter van Will, DFO Stock Assessment), and sockeye (Diana Dobson and Pieter van Will, DFO Stock Assessment) in the Vancouver Island & Mainland Inlets Region. For a general description of recruits-per-spawner methods, see Overview of Population Indicators: Recruits-per-Spawner.

5.7.2.8 Biological Status

Biological status for CUs in the Region was assessed using our standardized approach. See Benchmarks for Assessing Biological Status and Decision Rules for Assessing Biological Status for more details on biological status assessment methods.

5.7.3 Habitat Data and Analytical Methods

Nuances regarding habitat pressure indicator data and analytical methods for the Vancouver Island & Mainland Inlets Region are listed below. Refer to Habitat Status: Indicators & Benchmarks for information on habitat pressure indicators, benchmarks, and the analytical methods used to assess habitat status.

5.7.3.1 Trans-regional Conservation Units

The pink (odd-year) Homathko-Klinaklini-Smith-Rivers-Bella Coola-Dean CU spans the boundary between the Central Coast and Vancouver Island & Mainland Inlets regions.

5.7.3.2 Spawning Zones of Influence

Methods for delineating Chinook CU spawning zones of influence (ZOIs) vary by region in accordance with the CU delineation approach used by DFO. In the Fraser and Vancouver Island and Mainland Inlet regions, Chinook CUs are more broadly defined geographically, which meant that the methods employed for determining pink, chum, and coho spawning ZOIs were also applicable to Chinook CUs. The localized spawning ZOI for each VIMI Chinook CU was delineated by capturing the extent of all 1:20K FWA assessment watersheds that directly intersect with known spawning locations for Chinook.

5.7.3.3 Forest Disturbance on Southeast Vancouver Island

A large portion of southeast Vancouver Island is privately managed forests. As such, forest disturbance data sourced from DataBC in this area is either incomplete or not up to date. Efforts were made to source the best available data on forest disturbance for these privately managed forests, but we could not access this data. We defined a “Data Deficient” status for the forest disturbance indicator to overcome this challenge. The data deficient status was assigned for any watershed that was >= 50% privately owned forest. The exception was that if a watershed was high risk for forest disturbance based on the publicly available forest disturbance data, then that high-risk status was maintained and reported.

5.7.3.4 Additional Spawning Habitat Information Sources

In addition to the spawning habitat information we acquired from the Fisheries Information Summary System (FISS) database and local knowledge derived through expert elicitation, we received additional spawning habitat information from a technical report provided by Graham Murrell (Fisheries Manager, Hupacasath First Nation; Wright (2008)).

5.8 Columbia Region

The headwaters of the Columbia River in Canada are part of a vast system over 2000 km in length, with much of the watershed located within the continental United States (US). We have not assessed the biological status or threats to salmon habitats within those areas outside of Canada (Figure 5.8), having defined the Columbia region as the entirety of the watershed in Canada. There are two salmon CUs within the Canadian Columbia Region on the Pacific Salmon Explorer - one Chinook and one lake-type sockeye. The process of data gathering and synthesis to complete the initial assessments within the Columbia Region took place over a number of years and was completed in 2022.

Figure 5.8: Map of the Columbia Region.

The Columbia River has an extensive history of development, including dams – salmon have been extirpated from most of the upper Columbia drainage in Canada for more than 80 years. The Okanagan River sub-basin contains the only remaining salmon populations. While two CUs are currently defined, local and traditional knowledge and downstream observations suggest a spring Chinook run (distinct from the current Chinook CU) and coho also occur in the region. Steelhead passage also occurs through the Zosel dam, just south end of Osoyoos lake, a cross border lake.

5.8.1 Population Data and Analytical Methods

In the Columbia Region, we accessed datasets for biological indicators from published reports (Committee on the Status of Endangered Wildlife in Canada 2017; Hyatt and Stockwell 2019; Matylewich et al. 2019), DFO (Chuck Parken, pers comm), and the Sylix Okanagan Nation (Elinor McGrath, personal communication). Additional data was sourced from NuSEDS if applicable. For steelhead, there is no centralized public database for population data so these data were compiled from disparate sources, including from online databases, individual reports, and data custodians (see our steelhead-specific Github repository for all raw steelhead population data compiled). Details on specific data sources and analytical methods for the Columbia Region are described below.

5.8.1.1 Spawner Surveys

Spawner survey data for streams in the Columbia Region were sourced from DFO’s (New Salmon Escapement Database (NuSEDS), Chuck Parken, (pers comm), and the Sylix Okanagan Nation (Elinor McGrath, personal communication). For a description of the spawner survey indicator, For a description of the spawner survey indicator, see Overview of Population Indicators: Spawner Surveys.

5.8.1.2 Juvenile Surveys

Juvenile survey data for CUs in the Columbia were not available. For steelhead, juvenile survey data were sourced from the Okanogan Basin Monitoring Program. For a description of the juvenile surveys indicator, see Overview of Population Indicators: Juvenile Surveys.

5.8.1.3 Hatchery Releases

Hatchery releases in the Columbia Region for all species were provided by DFO (Brock Ramshaw, Salmonid Enhancement Program). Data on hatchery locations, release sites, and release numbers from the Freshwater Fisheries Society of BC are available through the Province of British Columbia’s BC Data Catalogue. Refer to Overview of Population Indicators, Hatchery Releases for details on data and analytical methods.’

5.8.1.4 Spawner Abundance

Observed spawner abundance for CUs in the Columbia Region, represent the total number of mature salmon that return to a CU to spawn in a given year, and were available from DFO’s (New Salmon Escapement Database (NuSEDS), Chuck Parken, (pers comm), and the Sylix Okanagan Nation (Elinor McGrath, pers comm). Stockwell and Hyatt (2003) describe survey methods and analytical techniques of summary estimates of annual escapement. Considerations in spawner abundance are also described in Overview of Population Indicators: Spawner Abundance. Columbia CU-level estimates of spawner abundance (run reconstructions) were also sourced from DFO’s (New Salmon Escapement Database (NuSEDS), Chuck Parken, (pers comm), and the Sylix Okanagan Nation (Elinor McGrath, personal communication). For steelhead, observed spawner abundance data for the Mid Columbia Summer CU were sourced from Wiens et al. (2012) and estimated spawner abundance data for the Mid Columbia Summer CU were sourced from the Okanogan Basin Monitoring Program Database.

5.8.1.5 Run Timing

Estimates of the average timing at which Okanagan watershed salmon return to spawn were based on run timing at Zosel Dam (Columbia River DART 2022). The duration of the timing of river entry has an assumed bell-shaped curve (i.e. normal distribution). The shape of the curve is defined by the mean and standard deviation of the available run timing data. For Osoyoos sockeye and Okanagan Chinook, the run timing values are comprised of averaged values from 2006-2017. Note that salmon migrating up the Columbia and Okanagan are known to be heavily affected by water temperatures in any given year (Hyatt et al. 2013). See Overview of Population Indicators: Run Timing for a description of the run timing indicator and methods.

5.8.1.6 Catch & Run Size

Catch and run size and subsequent exploitation rates for CUs on the Columbia were sourced from Hyatt and Stockwell (2019) for sockeye and were not available for Chinook. For a description of catch and run size methods see Overview of Population Indicators: Catch & Run Size.

5.8.1.7 Recruits-per-Spawner

Recruits-per-spawner data for CUs in the Columbia Region were not available. For a description of recruits-per-spawner methods, see Overview of Population Indicators: Recruits-per-Spawner.

5.8.1.8 Biological Status

The biological status assessments for CUs in the Columbia Region currently reflect sockeye data sourced from the Hyatt and Stockwell (2019) and DFO current to 2021. There was insufficient data for Chinook status assessment at this time, but an expert review (Committee on the Status of Endangered Wildlife in Canada 2017) determined an “Endangered” status with data to 2015. As new data become available, we will update the analyses and results in this report as well as on the Pacific Salmon Explorer. See Benchmarks for Assessing Biological Status and Decision Rules for Assessing Biological Status for more details on biological status assessment methods.

5.8.2 Habitat Data and Analytical Methods

Nuances regarding habitat pressure indicator data and analytical methods for the Columbia Region are listed below. Refer to Habitat Status: Indicators & Benchmarks for information on habitat pressure indicators, benchmarks, and the analytical methods used to assess habitat status.

5.8.2.1 Spawning Zones of Influence

Methods for delineating Chinook CU spawning zones of influence (ZOIs) vary by region in accordance with the CU delineation approach used by DFO. In the Fraser, Vancouver Island and Mainland Inlets, and Columbia regions, Chinook CUs are more broadly defined geographically, which means that the methods employed for determining pink, chum, and coho spawning ZOIs were also applicable to Chinook CUs. The localized spawning ZOI for each Columbia Chinook CU was delineated by capturing the extent of all 1:20K FWA assessment watersheds that directly intersect with known spawning locations for Chinook.

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