DRAFT

This is a draft document which will be continually updated. We are looking for feedback, especially if there are any life cycle timings that do not align with your knowledge of the CU. For feedback and questions please contact Stephanie Peacock (speacock[at]psf.ca) or Sam Wilson (swilson471[at]gmail.com).

1 Summary

We have estimated the timing of four key life stages for Conservation Units (CUs) of five Pacific salmon species and steelhead trout 1. PSF will be using this information to determine the relative exposure of CUs to climate changes in freshwater across four freshwater life stages: eggs/alevin, juvenile freshwater rearing, adult freshwater migration, and spawning.

In order to estimate these four freshwater life stages we collated information on the timing of four life stage events. These events are:

  1. Fry migration- the movement of fry from the gravel to freshwater rearing grounds, which marks the end of the egg/alevin life stage and beginning of the juvenile freshwater life stage.
  2. Ocean entry- juvenile migration into the marine environment - adjusted for downstream migration distance given average swim speeds where rearing locations (and points of data collection) are >~40km from the ocean. This life cycle event marks the end of the juvenile freshwater rearing stage.
  3. Adult freshwater entry – the entrance of returning adults into freshwater marks the beginning of the adult freshwater migration stage.
  4. Spawn timing – the start of spawning marks the beginning of the eggs/alevin stage and end of the adult freshwater migration stage (allowing for temporal overlap of stages to account for within-CU variability in timing).

For each of these life cycle events, we have estimated the start and end of the timing window as the 2.5th and 97.5th percentiles of the cumulative timing from available data for the CU.

Fry migration and ocean entry timing were determined through a literature review and compilation of historic data. Migration data were typically collected using rotary screw traps, incline plane traps, and fyke nets. Adult run timing was determined from reports of catch (e.g., Tyee test fishery; Albion fishery) assigned to CUs based on genetic stock identification. Spawn timing (except for steelhead) was estimated for each CU using NuSEDs data on start, peak, and end spawn times for river populations within that CU. Run timing and spawn timing for steelhead trout were collated from historic reports. In these reports, timing was typically determined using radio telemetry.

Although these sources represent the best publicly available information, the data on timing are limited. There are many CUs for which we were unable to find information on the above life cycle events, and CUs with information often have data from only a single location for a handful of years. As such, we are seeking input from experts to ensure the information is accurate. We would appreciate any feedback on the timing of life cycle events presented here, including suggestions for additional data sources (e.g., for run timing or for spawn timing in the Transboundary region).

Using these four life stage events we estimate four freshwater life stages:

  1. Incubation - begins with the 2.5% percentile of the cumulative spawn timing, and ends with the 97.5% percentile of the cumulative fry migration.

  2. Freshwater rearing - If juveniles rear for more than one year, this stage will span the whole year. If migration takes place within the first year (0+) then freshwater rearing begins with the 2.5% percentile of the cumulative fry migration, and ends with the 97.5% percentile of the cumulative ocean entry.

  3. Upriver migration - begins with 2.5% percentile of adult freshwater entry, and ends with the with the 2.5% percentile of spawning.

  4. Spawn timing –begins with the 2.5% percentile of the cumulative spawn timing, and ends with the 97.5% percentile of the cumulative spawn timing.

2 Life Cycle Tables

2.1 Fraser River Region

2.1.1 Fraser River Steelhead