Alaska biologists eye ocean shifts' effect on salmon
Craig Medred/Anchorage Daily News

Published Tuesday, June 23, 2009


ANCHORAGE, Alaska - A second straight year of weak king salmon returns around the rim of the Gulf of Alaska has state fisheries biologists wondering if they might be staring into the face of a bleak future.

Troubling discussions of PDO - an acronym for something called the Pacific Decadal Oscillation - have been spreading coast-wide as kings come back weak in river after river. Historically, there are indications that geographically widespread weakness like these are tied to a shift, or oscillation, in Pacific Ocean currents that causes cooler waters to pool in the Gulf of Alaska.

A cool phase in the Gulf from 1947 to 1976 corresponds neatly with the last big crash in king numbers in Cook Inlet. Most fisheries biologists agree that overfishing with commercial nets contributed to a nearly three-decade-long depression in king numbers there. But there is widespread agreement there was more to it than just heavy fishing.

Climate was identified as a significant player by fisheries scientist Steven Hare in 1996.
http://newsminer.com/news/2009/jun/23/biologists-wonder-if-ocean-shifts-affect-salmon/

This isn't going to sit well with the "high seas bogeyman" or the "commercial bait robbers" theorists.

http://www.thecordovatimes.com/news/story/6411

Like these High Seas Boogey men Freespool?

I would highly recommend reading about the PDO and how it effects ocean conditions directly related to salmon life history Aunty.
Unlike the conjured explanations dreamed up by sportanglers, this has scientific backing.

Historical records based on fish scale deposits in AK lake bottom coring samples track PDO shifts pretty closely. When AK has good fishing, our's isn't so good. When we're good, AK is depressed. It's generally a 25-30 year cycle. We may be on an up-swing....

Some info on PDO

http://www.atmos.washington.edu/~mantua/REPORTS/PDO/PDO_egec.htm

http://www.iphc.washington.edu/Staff/hare/html/papers/hare-francis/harefran.html

Good news for us!

We should be beginning to see the effects of favorable ocean conditions. Wasn't the PDO great for the 08 outmigrating year class? Might we see some fat coho this year since the 06 returns sucked, but the 08 marine conditions were great?

Actually I have heard that sub-adult survival is better with good PDO index, but adults end up smaller (more competition later for food). But if not many juveniles were present in 08 could it be possible to have high survival and large adults?

Always good to hope anyways.

Some nice reports already coming in from the WCVI fisheries of Chinook into the 30/40# range and decent sizes on Coho. Could be a good season......

"The marine life of the Alaskan salmon is unknown from
the time the young, in their newly-acquired silvery dress,
leave the fresh-water nursery to become salt-water sailors,
until they have ended their cruise, obtained their liberty,
and come ashore, when, as in the case of so many other
salt-water sailors, their serious trouble begins."

From Bean, T.  1890.  The Alaskan salmon and their allies.  Transactions of the American Fisheries Society.  19(1):49-66.

This bit of a scientific paper was sent to friends at the UW High Seas research program by an Alaskan biologist who knows a bit about ocean salmon ecology after reading the article cited in this thread. It still expresses the attitude of so many salmon biologist and managers. Whenever things go wrong in spite of their best efforts the problem is the ocean, a black box. When runs are good it is because of excellent management. The PDO now falls in to the same category. It is still a black box but now it flips every 30 years. The PDO is an important concept but ocean salmon ecology is much more complicated than a simple bipolar mechanism. Climate change, ocean acidification, and carrying capacity issues may override the effects of the PDO. The managers who view the ocean as a black a box only bury their head in the sand deeper when asked how they might change their practices to deal with ocean effects. They don't want to know, they don't want research and they ignore the information that is available. I might add that of all the agencies that manage salmon WDFW is one of the best at incorporating ocean science in their management. In any case I wouldn't get too excited about how the PDO may predict this years returns to Washington, remember the Columbia spring chinook this year.

I'd aslo like to note the CR Summer Chinook catch was only about half of expectations for the killnets. Where did these fish go?

Last year it was reported there were some 11K chinook wasted as bycatch along the Coast by the hake/whiting trawls.

How many are we allowed again?

Uh it is habitat....stupid!

Good conditions in the ocean only work when there are fish to work with. If the FW habitat is unproductive or underseeded, you don't get much.

This year's Lake WA sockeye are a case in point. Since so few smolts made it out of the lake it would a huge marine survival to get a fishery. Maybe we will get a great marine survival, and that will give us 100K.

The whole damn system has to be working, together, to get big runs.

It should be noted that while it is fairly straight forward to look at historic information and pin point when one of these survival shifts occurred it is rare that such shifts can be determined precisely in real time.

It may also be the case that such shifts have different timing in different parts of the ocean. The Pacific is such a large body of water it is hard to imagine that it would act the same across that broad landscape.

It is clear that more and more signs are coming in that we MAY be on the cusp of another suvival shift; we will know with more certainity in 5 years or so. Something to keep in mind is that off the Washington/Oregon coasts that indications are that ocean conditions did not improve (cooler temperatures) until 2008. Those juveniles of the Chinook returning to the Columbia and elsewhere in the region this year were all ready at sea prior to that time so one would not expect to see this years runs of adults to have benefited from the improved conditions (this year's jacks may have).

The optomist in me hopes that we are seeing such a shift in survivals and if one wants to look for early signs of such a major change we can look at this year's pink and coho returns here in Puget Sound. If the pinks come in below expectations (forecast) and the coho above expectations we will have a couple more check marks on the positive side of the ledge indicating a suvival shift.

Tight lines
Curt

To arbitrarily discount the effect of habitat on the dwindling wild salmonids populations is stupid!
Oh and who are "you people"?
Seems like the CCA Kool-Aid drinkers are stuck on gill nets as the only culprit... Talk about a fools errand.

I think bit more info about the PDO and predicting salmon returns is worthwhile. The most important fact is that all of the data used to develop the relationship between the PDO and salmon returns was pink chum, and sockeye data. Chinook, coho , and steelhead data was not used as they are minor species in the scheme of things. Also they spend more time in freshwater so that ocean temperature effects are more indirect, being related through the coupling of weather systems to ocean temperatures. It is also important to note that chinook and steelhead from Washington, Oregon and Alaska are found in the same regions of the Gulf of Alaska and to some degree in the Bering Sea. It is not reasonable to think that a change in ocean conditions would have a differential effect in survival on different chinook stocks that are sharing the same area of the ocean. Another interesting effect occurs with sockeye. The major sockeye stocks occur in western Alaska and in Kamchatka in river systems that drain into the Bering Sea. The relative abundance of the two stocks is influenced by the Aleutian low pressure center which has a major effect on the weather in Alaska and in Kamchatka. The controlling factor on sockeye abundance is not the strength of the Aleutian low but its position.

I must say once again to differentiate habitat from ocean conditions is a major error. Ocean is habitat and for anadromous fish it is important, otherwise they wouldn't have evolved to be anadromous. Steelhead (and Atlantic salmon) are a good example. When the risks of migrating to salt water out weigh the benefits they stay in freshwater. The rainbow trout of western Alaska are a good example.

I believe it is sub-adult survival which leads to more returning adults with regards to the PDO.

Some highlights from "EFFECTS OF INTERDECADAL CLIMATE
VARIABILITY ON THE OCEANIC ECOSYSTEMS OF THE NE PACIFIC" (R.C. FRANCIS, S.R.HARE, A.B.HOLLOWED and W.S.WOOSTER, 1998)

http://www.iphc.washington.edu/Staff/hare/html/papers/JClimate/JClimate.pdf

"Salmon appear to be affected by climate early in their marine life history."

"For the past 20 years, conditions have been favorable for Alaskan salmon and unfavorable for Pacific North-west salmon. They point out that a significant shift in zooplankton biomass as well as its distribution around the Subarctic Gyre has provided favorable feeding
conditions for migrant salmon smolts during a highly critical stage in their life history.

Conversely, the dramatic decrease in zooplankton biomass off the Pacific North-west coast due to stratification of California Current waters and loss of advective products frm the West Wind
Drift presents a relatively barren oceanic environment for Pacific North-west smolts"


Lots of good info here if you have the time...I wouldn't say that ocean conditions for coho and chinook are less direct though.

Darn interesting. ( Dare I say darn on this forum?)