A new journal article examines hypotheses for the decline and poor recovery of Prince William Sound herring, and identifies hatchery pink salmon among possible culprits.
The article finds "no evidence that oil exposure from the Exxon Valdez oil spill, harvest effects, spawning habitat loss, the spawn-on-kelp fishery, or disease have led to either the decline or poor recovery of PWS herring."
Here's the article abstract:
This paper updates previous reviews of the 1993 stock decline of Pacific herring (Clupea pallasi) in Prince William Sound, Alaska, and focuses on hypotheses about subsequent poor recovery. Recent age structured assessment modeling with covariate analysis indicates that the population dynamics of the sound’s herring are influenced by oceanic factors, nutrition, and, most substantially, hatchery releases of juvenile pink salmon. For the 1993 decline, poor nutrition remains the most probable cause with disease a secondary response. Concerning poor recovery, we examined 16 potential factors and found three to be causal: oceanic factors, poor nutrition, and hatchery releases of juvenile pink salmon. Absences of strong year classes at both Sitka and Prince William Sound after 1993 indicate the action of large-scale ocean processes. Beyond regional-scale environmental factors, two factors specific to the sound influence the population dynamics of herring and are likely impeding recovery. First, pink salmon fry releases have increased to about 600 million annually and may disrupt feeding in young herring, which require adequate nutrition for growth and overwintering survival. Juvenile pink salmon and age-1 herring co-occur in nearshore areas of bays in late spring and summer, and available data on dietary overlap indicates potential competition between the age-1 juvenile herring and juvenile pink salmon. Field studies demonstrate that juvenile herring reduce food intake substantially in the presence of juvenile pink salmon. Second, overwintering humpback whales may consume potentially large amounts of adult herring, but further studies must confirm to what extent whale predation reduces herring biomass.
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15 comments:
So lets get rid of hatchery fish and wipe out the whales. problem solved.
No,just the hatchery fish, but then you must be hatchery co-dependent.
Hey, PWS has killed Lower Cook Inlet pink salmon runs too, who cares? Seriously, the monster must be stopped.
PWS pinks have also been implicated as a cause of global warming and the Exon oil spill.
Admittedly I don't know all of the details, but I did note that this study was funded by Exxon Mobile Corporation. Just something to note.
Indeed, in the acknowledgments at the end of the article, we find this:
"Exxon Mobil Corporation supported this effort."
blame exxon not pws pinks and lower cook inlet fishermen are just pissed that last years catch was so huge and they didn't catch crap
So was that a voluntary donation by Exxon Mobil or part of the EVOS monies?
If voluntary, how much of it was paid for by Exxon Mobil?
Was the report peer-reviewed to be accepted for publication?
Does anyone contest the fact that 600 million hatchery released juvenile pink salmon compete for the same food resources in PWS as do young herring?
And that having 600 million hatchery released juvenile pink salmon might reduce the food supply, and hence the survival rates, of young herring?
A spade is still a spade.
Does anyone dispute the fact that there was a big-ass oil spill just before the herring crashed?
An oil company is still an oil company.
No, the research was not supported by EVOSTC but by the Exxon Mobil Corporation itself. In all honesty, I don't know the process they went to to get the funding, since most funding agencies publish an RFP (Request for Proposals) and potential reward amounts for different subject areas. The lead author is listed as an expert on the Exxon Mobil website: http://www.acpt.exxonmobil.com/Corporate/about_issues_valdez_contacts.aspx and is connected with Battelle which is a research lab operated for the Department of Energy.
That certainly does put the conclusions under suspicion but it was also peer-reviewed and accepted into a fairly reputable publication.
If pink salmon predation is keeping herring numbers down that's fairly easy to measure (collect smolts - open their bellies) and estimate the impact. Think about it - even if each pink salmon only ate one age 0 herring that's 600 million individual herring gone right there.
Hey braniac, it said they are competing for the same food, not that pink salmon were predating on herring. This is just another slimey trick by Exxon to try to make themselves look good. And gee, now they have a spill in the Yellowstone River to cover up. and the huge settlement back east for the gas spill in 2006. They sure keep a lot of lawyers busy and propaganda-ists.
Similar in nature to the competition for food between Arrow-tooth flounder and Halibut being blamed for the decline of the latter. The true cause can be easily traced to unobserved and underreported fishing that takes place, just like we know that a bunch of oil on the kelp and beaches will destroy Herring eggs and cause a marked decline in adult fish several years later...
The so called "scientists" are full of shit. You can explain away just about any hypothesis with enough grant money and biased research. When this research trumps even common knowledge that a 10 year old can understand it makes us the rest of us look pretty stupid and helpless. The only one who wins is Exxon.
The abstract doesn't mention predation, but the entire article does - predation on age-0's, competition with age-1's. signed, brainiac.
I wonder if the hatchery pinks had anything to do with the lesions that showed up on the herring just after thew oil spill. It has been proven that these lesions werecaused by hydrocarbon. Lets see spill actually way more than 11 million gallons of oil less than a mile from the primary spawning ground for PWS herring (Tatitlik narrows) exactly when the herring are in to spawn , the stocks get lesions and plummet , later we can blame the hatchery program that has already been there for 20 years with no ill effect on herring.More Exxon Lies!
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