Fraser River environmental watch

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Environmental watch reports for summer 2020

Program information

The DFO Environmental Watch (EWatch) Program provides scientific advice on the impact of different environmental factors on the migration success of Pacific salmon in fresh water. This advice is based on our understanding of migration biology of Pacific salmon and the interaction with environmental conditions.

We address our research objectives using a three-fold approach:

  1. Monitoring, analysis, and forecasting of Fraser River environmental conditions
  2. Field and laboratory research on migration biology of Pacific salmon
  3. Quantitative modeling of salmon migration behaviour and success

We combine information from our environmental and biological monitoring programs to develop quantitative models that can be used to evaluate and forecast the influence of freshwater conditions on salmon migratory success. The environmental monitoring program consists of a comprehensive network of temperature logger stations along key salmon migration routes in operation since the 1990's. The biological research component of our program seeks to better understand the relationships between freshwater migration conditions and salmon reproductive development, stress response, disease, energy utilisation, migration behaviour, thermal ecology, and homeostasis. Ultimately, the research conducted through the EWatch program is used to provide scientific advice to both fisheries and habitat managers based on a combination of environmental forecasts, ecological modeling, and salmon migration research. A specific example is the provision of pre-season and in-season scientific advice to fisheries managers to assist in the prediction of en route loss (salmon that die in fresh water during their migration to the spawning grounds) and pre-spawning mortality (salmon that survive to the spawning grounds but die before they successfully deposit all of their eggs) associated with adverse river conditions.

Map: Temperature Stations & Spawning Grounds

Locations of key EWatch and WSC temperature monitoring stations and major Fraser River sockeye salmon spawning grounds.

Long text version

Temperature station: 7 along the Fraser River North of Chilko. 9 along the Fraser River by Shuswap and South of Shuswap.

Spawning ground: Stuart, Nechako, Chilko, Quesnel, Shuswap

The majority of work conducted by EWatch is enhanced by facilitating additional research on Pacific salmon and environmental monitoring through productive collaborations with other research groups within DFO and external government and academic institutions, including University of British Columbia, Simon Fraser University, Carleton University, Pacific Salmon Commission, University of Northern British Columbia, BC Ministry of Environment, and Dalhousie University (EWatch Collaborators). Current research projects and interests include: salmon carcass behaviour, reproductive physiology of adult migrants, thermal tolerance and disease progression, inter-annual variation in energy status of returning sockeye, causes of pre-spawning mortality, post-release stress from fishing, sockeye thermal ecology, climate impacts on migration conditions, smolt condition during freshwater migration, fry out-migration behaviour, juvenile swim performance, and intergenerational consequences of harsh migration conditions on egg-fry survival and offspring fitness (EWatch Publications).

In early June, the EWatch program generates long-range forecasts of lower Fraser River summer temperature and flow conditions using relationships between winter snowpack accumulation, summer air temperatures and river environmental conditions (Patterson and Hague 2007). Long-range forecasts can be used to guide pre-season fishery planning given the expected environmental conditions in the river and their potential impact on returning adult salmon. Average 31-day temperature and flow conditions for the current year from forecasted summer air temperature anomalies for BC (provided by Environment and Climate Change Canada - ECCC) and the forecasted contribution of snowmelt to summer flows (provided by the BC River Forecast Centre). Fraser River discharge data are provided by Water Survey of Canada (WSC / ECCC) calculated from water height data collected on a real-time basis from a site in the lower river. Fraser River water temperatures are provided by real-time data loggers placed at sites throughout the Fraser Basin operated by EWatch and Water Survey of Canada. These forecasts are updated in bi-weekly online reports from July to September to provide information to fisheries managers on the status of freshwater migration conditions for incoming sockeye salmon runs.

Long-range forecasts of lower river temperature and flow issued June 1, 2020 predict above average flows and average to above average temperatures for the lower Fraser River at Hope during the summer of 2020.

Graph: 31-day average lower Fraser River pre-season temperature forecast centered on each date.

31-day average lower Fraser River pre-season temperature forecast centered on each date.

The bars indicate the approximate date range over which different sockeye salmon management groups pass the lower river temperature stations (1 = Early Stuart; 2 = Early Summer; 3 = Summer; 4 = Lates).

Long text version

Graph showing temperatures in °C for the historic mean from 1950 to 2019 and the 2020 predicted values.

Trends show the historic mean starts at approximately 14.5°C in the beginning of July, rising to its peak at 18.0°C around August 7. It then declines to approximately 14.5°C mid-September. The predicted 2020 temperature starts at approximately 15.0°C in the beginning of July, rising to its peak at approximately 18.8°C around August 7. It then declines to approximately 15.5°C in mid-September. The 2020 prediction remains higher than the historic mean.

Approximate date range over which different sockeye salmon management groups pass the lower river temperature stations:

Graph: 31-day average lower Fraser River pre-season discharge forecast

31-day average lower Fraser River pre-season discharge forecast centered on each date.

The bars indicate the average date range over which different sockeye salmon management groups pass the lower river discharge stations (1 = Early Stuart; 2 = Early Summer; 3 = Summer; 4 = Lates).

Long text version

Graph showing discharge in m3/s for the historic mean from 1912 to 2019 and the 2020 predicted values.

Trends show the historic mean starting slightly above 6 000 m3/s in the beginning of July and declining gradually to a low of approximately 2 500 m3/s in mid-September. The 2020 predicted discharge starts at around 7 000 m3/s in the beginning of July and declines gradually to approximately 2 500 m3/s in mid-September. The 2020 prediction remains higher than the historic mean until around August 20, where it remains slightly below the historic mean until mid-September.

Average date range over which different sockeye salmon management groups pass the lower river discharge stations:

Graph: 31-day average Fraser River at Texas Creek pre-season discharge forecast centered on each date.

31-day average Fraser River at Texas Creek pre-season discharge forecast centered on each date.

The bars indicate the average date range over which different sockeye salmon management groups pass the lower river discharge stations (1 = Early Stuart; 2 = Early Summer; 3 = Summer; 4 = Lates).

Long text version

Graph showing discharge in m3/s for the historic mean from 1952 to 2019 and the 2020 predicted values.

Trends show the historic mean starting slightly below 4000 m3/s in the beginning of July and gradually declining to slightly below 2000 m3/s in mid-September. The 2020 predicted discharge starts slightly above 4000 m3/s in the beginning of July and declines to slightly below 2000 m3/s in mid-September. The 2020 prediction remains higher than the historic mean.

Average date range over which different sockeye salmon management groups pass the lower river discharge stations:

Graph: 31-day average Fraser River at Texas Creek pre-season temperature forecast centered on each date.

31-day average Fraser River at Texas Creek pre-season temperature forecast centered on each date.

The bars indicate the average date range over which different sockeye salmon management groups pass the lower river discharge stations (1 = Early Stuart; 2 = Early Summer; 3 = Summer; 4 = Lates).

Long text version

Graph showing temperatures in °C for the historic mean from 1996 to 1998 and 2002 to 2019, and the 2020 predicted values.

Trends show the historic meaning starting at about 15.9°C in the beginning of July and rising gradually to its peak of approximately 18.5°C around the beginning of August, where it then declines gradually to a temperature slightly higher than 14.0°C in mid-September. The 2020 predicted temperature starts at about 15.0°C and rises to its peak of approximately 18.0°C in the beginning of August. It then declines gradually to a temperature slightly below 14.0°C in mid-September. The 2020 prediction remains smaller than the historic mean.

Average date range over which different sockeye salmon management groups pass the lower river discharge stations: