DOI: 10.5061/dryad.wm37pvmwx
title: Freshwater life-cycle timing of Pacific salmon and steelhead (Oncorhynchus spp.) in Canada

description: Understanding species’ phenology and distribution is essential for
 mitigating anthropogenic disturbances and understanding climate change
 vulnerability. Pacific salmon (Oncorhynchus spp.) have complex life cycles
 that span freshwater and marine environments and unfold over many
 thousands of kilometers. Currently, there is no central repository of
 life-cycle timing for unique salmon and steelhead populations throughout
 their Canadian range. We have compiled a dataset of timing for key
 freshwater life-cycle events - fry migration from incubation to rearing
 grounds, juvenile migration from rearing grounds to the ocean, adult entry
 into rivers, and spawning - for salmon and steelhead trout from British
 Columbia and the Yukon, Canada. We summarize patterns across species and
 populations to improve understanding of when species are in different
 freshwater habitats but found significant data gaps in remote regions that
 may challenge environmental planning. The data and insight we provide
 allow for more detailed examination of how salmon and steelhead
 populations will be exposed to future climate changes and can be used to
 inform adaptive management of fisheries and mitigation during human
 development.
description: The life cycle events we estimated are:
   1) fry migration- the movement of fry
 from the gravel to freshwater rearing grounds
   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 &gt;~40km from the ocean.
   3) adult run timing – the entrance of
 returning adults into freshwater.  
 4) spawning   
 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.
   Note (1) Conservation Units have been
 defined under Canada’s Wild Salmon Policy as ecologically and genetically
 unique groups of salmon that, if extirpated, are unlikely to be
 recolonized within an acceptable timeframe. Steelhead were not formally
 included in the Wild Salmon Policy or work led by DFO to define CUs for
 salmon. However, past work has been done to define 36 provisional CUs for
 steelhead in BC, which characterize the biodiversity of steelhead in BC
 using similar methods to those used to define salmon CUs (Tautz et al.
 2011, Parkinson et al. 2005). Future work is needed to review and
 potentially refine these steelhead CUs based on more recent research and
 data to ensure they fully capture the diversity of steelhead in BC and
 meet the Wild Salmon Policy's definition of a CU. We have used
 provisional steelhead CUs from Tautz et al. (2011) for the Skeena Region
 and from Parkinson et al. (2005) for all other Regions when summarizing
 timing data."
description: # Freshwater life-cycle timing of Pacific salmon and steelhead
 (Oncorhynchus spp.) in Canada
 [https://doi.org/10.5061/dryad.wm37pvmwx](https://doi.org/10.5061/dryad.wm37pvmwx) ### Summary We have estimated the timing of four key life cycle events for Conservation Units (CUs) of five Pacific salmon species and steelhead trout (1) . ### File Descriptions: 1Life cycle timing by reference.xlsx - This file documents the individual references from which data was extracted, as well as the raw data. Some reports document multiple years, while others are annual reports. Data were extracted from each referenced report. To be included, the observation period must span the majority of the migratory period, there must be enough salmon to establish a migration timing window estimate. 2Life cycle timing by location - This file documents data summarized by each location where observations occured. Data is summarized from the Life_cycle_timing_by_reference document. Here each location is listed with corresponding data on site and life cycle event. When multiple years were reported the data are reported as the mean, weighted by the number of years. So if there were 2 years of data, summarized information is the simple mean, whereas if one report documented 3 years, and another report documented 1 year, the first report would be have higher weight (eg. (report 1 data)*0.75+(report 2 data)*0.25). In a few cases observations were collected at different locations from the same population/river but far apart. In this case the data were summarized seperately and a descriptor was added (e.g. adams upper, adams lower). 3Life cycle timing by CU - This file documents data summarized by each conservation unit (CU) where observations occured. Data is summarized from the Life_cycle_timing_by_location document AND from summary of NUSEDS spawn timing. When multiple sites were reported within a CU the data are reported as the mean, weighted by the number of sites and years. So if there were 2 years/sites of data, summarized information is the simple mean, whereas if one site had 3 years, and another site had 1 year of data, the first site would be have higher weight (eg. (site 1 data)*0.75+(site 2 data)*0.25).