Thursday, September 16, 2010

A Little Perspective on Huge Sockeye Returns


After a controversial and disappointing return last year, when runs fell short of the preseason forecast by almost 10 million fish the system is seeing one of the best returns of sockeye in recent memory. To date DFO estimates that around 34 million sockeye are returning to the Fraser. Better news yet, the river is relatively cool this year reducing the risk that the fish will experience high prespawn mortality which has plagued the run in recent years. Society and the media tend to have short memories, particularly when it comes biological system and while last years collapse led to calls for reform to fisheries management, salmon farming and forecasting models, this year the otherside is shooting back arguing that the large return means nothing is wrong with the Fraser.

When considering a record return like this, it is important to put it in context. Yes, this large run is encouraging and is worth celebrating. But before we get too ahead of ourselves let us consider a few facts. This run isn't actually that big when compared to historic runsizes. At the beginning to the 20th century the Fraser annually recieved returns ranging from 60-100 million fish meaning this years record return is only about half of historic abundance, if that. The productivity of Fraser Sockeye has been declining steadily since the 1990s. That means for every individual that returns fewer offspring are surviving to adulthood. Some are quick to blame fish farms, others point to climate change. Whatever the cause, and there are likely many, the productivity of a run can only decline so far before they are below replacement and sprial towards extinction. Less productive runs means less abundance for harvest, fewer marine derived nutrients reaching the river systems of the Fraser and less resilience in sockeye populations.

This years banner return is worth celebrating. It means for one more generation, sockeye remain abundant in the Fraser. Still the future remains uncertain and it is essential that we as a public take the long view of salmon populations, demanding action from our governments that will protect the fundemental ecosystem properties which support abundant salmon.

Good perspective on the Fraser in the High Country News:
http://www.hcn.org/hcn/blogs/range/mystery-salmon

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