An interesting point was made by a somewhat surprising source (Plunker), but one which merits some attention regarding the decline our fisheries. The ocean survival of adult salmon and steelhead has declined over the past few decades as well as the spawning and juvenile habitats in streams. The causes of lower ocean survival are not known (or at least not quantified), but are undeniable. Over the past couple of years I have had the opportunity to work in this area, at least indirectly, and I'd like to share some of things that are known or suspected.

We have all have heard of El Nino/La Nina, the 1 or 2 year weather events that come every so often to wreak havoc on run sizes. Sometimes it seems that WDFW is hanging their hat on this weather phenonmenon a little too often, but studies have shown that they do affect ocean survival.

There is another weather pattern that is even longer term or even more significant called the Pacific Interdecadal Oscillation (PDO for short--thank some climatologist for the huge term). The PDO is a 20 to 30 year cycle of relatively dry/warm winters to wet/cool winters in the northwest. According to climatologists and oceangraphers, from 1947 to 1976 we were in the wetter/cooler pattern, from 1977 to 1997 we were in a dry/warm pattern. And beginning in 1998, it seems we've again begun another cool/wet pattern.

What does this have to do with fisheries? Fishery statistics over these years show that in the dry warm pattern, Alaskan salmon fisheries generally flourish, while WA, OR fisheries are below normal, and vice versa for the wet/cool pattern. The Alaska Bristol Bay Sockeye fishery is a good example of having a good two decades of fishing. Post-World War II catches, on the other hand in Alaska, were substantially lower.

Just the opposite has occurred over the same period in the northwest. Relatively strong commercial fisheries were observed Post WWII until the late seventies, followed by marked declines. Not just for sportsmen, but totals numbers--sporties, commercials, and tribes--there were just fewer fish than expected.

Warmer ocean temperatures over the past 20 years are also speculated for contributing to the decline of Puget Sound groundfish stocks, particularly Pacific cod, pollock, rockfish, and herring. There have been no commercial fishing efforts on cod since the eighties, yet there has been absolutely no recovery of this species. Rockfish are faring a little better. The difference in the two is that cod are near the southern end of their habitable range, so increases in average temperature would likely have a more negative impact. Rockfish, on the other hand, have stocks well into California, so are more tolerant of warmer water.

If the past is an indicator of the future, the outlook may not be so dire. As said, we are now moving into a relatively cooler/wetter pattern and it should last for the next 20 or so years. A look at Puget Sound herring stocks over the past couple of years has shown improvements in populations, although its too soon to tell.

There are certainly other factors involved with the decline of our runs. But if you've looked at the long term stats, the evidence is somewhat compelling. Diligent conservation and management efforts need to be adhered to, after all, overfishing and habitat degradation is all too real. However, it should also be realized that mother-nature beyond the reach of humans may also play an all too real role, as well.


[This message has been edited by obsessed (edited 04-07-2000).]

[This message has been edited by obsessed (edited 04-07-2000).]