Late-run Sockeye Salmon Review
Migration Behaviour and Mortality of Late-run Fraser River Sockeye Salmon
The Fraser River Panel agreed in October, 2000, to bilaterally develop research proposals to address the causes of early upstream migration behaviour of Late-run sockeye. In June, 2001, the Pacific Salmon Commission’s Standing Committee on Scientific Cooperation approved funding for seven studies on the potential causes of this early migration behaviour.
Summaries of the resulting studies conducted, research plans and fisheries management considerations can be found below.
Late-run sockeye have historically delayed in the lower Strait of Georgia for four to six weeks prior to entering the Fraser River en route to their spawning grounds. Since 1996, Late-run sockeye (excluding Birkenhead sockeye) have often entered the Fraser River with little or no delay, which has resulted in mortality rates of some Late-run sockeye stocks exceeding 90% in some years.
The cause(s) of this early entry behavior have not yet been identified, despite intensive and on-going research studies. Some of the most serious implications of this early entry behavior of Late-run sockeye are that:
- the future viability of some Late-run stocks may be jeopardized; and
- substantially lower harvest rates on Late-run and Summer-run sockeye (a portion of which overlap in their migration timing with Late-run fish) have been necessary in recent years to help ensure that Late-run sockeye stocks are conserved.
The greatly reduced harvest rate on Fraser River sockeye is having significant adverse impacts on the multitude of commercial and non-commercial users of this resource. The severe curtailment of harvest has been necessary to protect the sustainability of Late-run stocks, including the famous Adams River sockeye run.
Late-run Sockeye Salmon publications