Fraser River Environmental Watch

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 fresh water conditions on salmon migratory success. The environmental monitoring program consists of a comprehensive network of temperature logger stations along key sockeye salmon migration routes in operation since the 1990’s. The biological research component of our program seeks to better understand the relationships between fresh water 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 temperature monitoring stations and major Fraser River sockeye salmon spawning grounds.

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, University of Guelph, McGill University, and Rutgers 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 fresh water migration, fry out-migration behaviour, juvenile swim performance, and the 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 Canada) and the forecasted contribution of snowmelt to summer flows (provided by the BC River Forecast Centre). Fraser River discharges are provided by Environment Canada (Water Survey of Canada) 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 fresh water migration conditions for incoming sockeye salmon runs.

Long-range forecasts of lower river temperature and flow issued June 1, 2010 predict below average flows and above average temperatures for the lower Fraser River during the summer of 2010.

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

31-day average lower Fraser River pre-season temperature forecast centered on each date. The coloured bars indicate the average 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).

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 coloured 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).

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