ENVIRONMENT YUKON






 

Fish

Number of spawning Chinook salmon

 

Significance

Chinook salmon are a key food source for bears, eagles and other predators and they bring nutrients from the ocean to freshwater and terrestrial ecosystems. Salmon are important culturally, socially and economically in Yukon.

 

Salmon in the Takhini River.

 

Chinook salmon returns vary considerably due to a number of factors, including:

  • the strength of returning age classes,
  • in-river harvest,
  • offshore unintentional by-catch in the pollock fishery,
  • predation,
  • disease,
  • water levels,
  • temperature, and
  • environmental variables, e.g., climatic events such as the Pacific Decadal Oscillation, El Niño, and La Niña.

The international Yukon River Salmon Agreement has formally been in place since 2002 to help rebuild and conserve Canadian-origin salmon stocks and to define harvest allocations to Canadian and U.S. fisheries. The Yukon River Panel established a spawning conservation target for the number of Chinook salmon returning to spawn in the Canadian portion of the Yukon River.

The goal is for an escapement (number of fish reaching spawning grounds) of 42,500 to 55,000 fish; this is tracked by the federal government through Fisheries and Oceans Canada.

 

What is happening?

 

  • In 2016, the spawning conservation target for Yukon River Chinook was met, with a preliminary estimate of approximately 70,000 fish reaching their spawning grounds in the Yukon (Figure 1).
  • This was the fifth time in the last ten years that the spawning escapement target was met, and one of the highest escapements on record.
  • The 2016 drainage-wide run size (i.e., the number of Chinook salmon that entered the river) was not particularly strong. As such, the high spawning escapement was only made possible through closures to the commercial, domestic and recreational fisheries, and significant harvest restrictions in subsistence and First Nation fisheries in Alaska and Yukon.

 

Figure 1: Number of Chinook salmon spawning in the Canadian portion of the Yukon River, excluding the Porcupine River drainage.
Source: Yukon River Salmon Season Summary and Season Outlook.

 

Taking action

 

To maintain a healthy number of spawning salmon even in this time of low productivity, fisheries managers in Yukon and Alaska have undertaken a range of actions, including:

  • full or partial closures of commercial, domestic and recreational fisheries,
  • closing key staging or salmon spawning areas to angling,
  • decreasing mesh sizes, and
  • reducing fishing times.
  • In addtion, Yukon First Nations have placed voluntary restrictions or avoided subsistence harvesting activities in years of low returns.

    The Yukon River Panel, established by the Yukon River Salmon Agreement, recommends spawning goals, reviews management strategies and conservation objectives, and funds restoration and enhancement projects focusing on Canadian-origin salmon stocks.

     

    Children releasing salmon into Wolf Creek.

     

     

    Data quality

    Estimates of the total number of salmon that return to their spawning grounds in Yukon are based on sonar passage estimates in Eagle, Alaska and harvest estimates from fisheries upstream of the sonar in both Alaska and Yukon.

    In addition, a number of counting projects in the upper Yukon River watershed are used to monitor the number of adult salmon that reach specific spawning tributaries. These projects also evaluate the proportion of adult female to male salmon, and the size and age of fish returning to spawn.

     

    References

    The United States and Canada Yukon River Joint Technical Committee. 2001-2015. Yukon River Salmon Season Summary and Season Outlook. Alaska Department of Fish and Game, Anchorage, Alaska, U.S.A. [cited 2016 Mar 3]. Available from: http://yukonriverpanel.com/salmon/publications/joint-technical-committee-reports/.

    Yukon River Panel. 2008. Salmon [cited 2016 Mar 3]. Available from: http://yukonriverpanel.com/salmon/.