Alaska | Northwest Coast Energy News

Letting salmon escape from nets could benefit grizzly bears and even the fishers, study says

Grizzly eating a salmon — A grizzly bear eats a salmon. A new study says managers must consider the value of salmon to the entire ecosystem. (Jennifer Allan)

A new study suggests that the health of the grizzly bear population is also a strong indicator of the health of Pacific salmon—and perhaps surprisingly, allowing grizzlies to consume more salmon will, in the long term, lead to more, not less, salmon.

The study, led by Taal Levi, of the University of California at Santa Cruz and colleagues from Canada, suggests that allowing some more Pacific salmon to escape the nets of the fishing industry and thus spawn in coastal streams would not not only benefit the natural environment, including grizzly bears, but could also eventually lead to more salmon in the ocean. Thus there would be larger salmon harvests in the long term—a win-win for ecosystems and humans.

The article, “Using Grizzly Bears to Assess Harvest-Ecosystem Tradeoffs in Salmon Fisheries,” was published April 10 in the online, open-access journal PLoS Biology. In the study Levi and his co-authors investigate how increasing “escapement”—the number of salmon that escape fishing nets to enter streams and spawn—can improve the natural environment.

“Salmon are an essential resource that propagates through not only marine but also creek and terrestrial food webs,” said lead author Levi, an environmental studies Ph.D. candidate at UCSC, specializing in conservation biology and wildlife ecology.

Salmon fisheries in the northwest Pacific are generally well managed, Levi said. Managers determine how much salmon to allocate to spawning and how much to harvest. Fish are counted as they enter the coastal streams. However, there is concern that humans are harvesting too many salmon and leaving too little for the ecosystem. To assess this, the team focused on the relationship between grizzly bears and salmon. Taal and his colleagues first used data to find a relationship between how much salmon were available to eighteen grizzly bear populations, and what percentage of their diet was made up of salmon.

The study looked at Bristol Bay, Alaska, the Chilko and Quesnel regions of the Fraser River watershed and Rivers Inlet on the Inside Passage, just northeast of northern Vancouver Island.
The study says adult wild salmon are “critical” to ocean, river and terrestrial ecosystems. As well as humans, salmon are eaten by orcas, salmon sharks, pinnipeds (seals and sea lions). On land, salmon are eaten by black and grizzly bears, eagles and ravens.

Because the grizzly is the “terminal predator” the study says “if there are enough salmon to sustain healthy bear densities, we reason there should be sufficient salmon numbers to sustain populations of earlier salmon-life history predatory such as seabirds, pinnipeds and sharks.”
As is well known in the northwest, the study says “bears are dominant species mediating the flow of salmon-derived nutrients from the ocean to the terrestrial ecosystem. After capturing salmon in estuaries and streams grizzly bears typically move to land to consume each fish, distributing carcass remains to vertebrate and invertebrate scavengers up to several hundred metres from waterways.”

“We asked, is it enough for the ecosystem? What would happen if you increase escapement—the number of fish being released? We found that in most cases, bears, fishers, and ecosystems would mutually benefit,” Levi said.

The problem, the study says, is that fisheries management have a narrow view of their role, what the study calls “single-species management,” concentrating on salmon and not the wider ecosystem. “Currently,” the study says, under single-species management, fisheries commonly intercept more than 50 per cent of in bound salmon that would otherwise be available to bears and the terrestrial and aquatic ecosystems they support.”

The relationship between salmon and bears is basic, Levi said. “Bears are salmon-consuming machines. Give them more salmon and they will consume more—and importantly, they will occur at higher densities. So, letting more salmon spawn and be available to bears helps not only bears but also the ecosystems they nourish when they distribute the uneaten remains of salmon.”

When salmon are plentiful in coastal streams, bears won’t eat as much of an individual fish, preferring the nutrient-rich brains and eggs and casting aside the remainder to feed other animals and fertilize the land. In contrast, when salmon are scarce, bears eat more of a fish. Less discarded salmon enters the surrounding ecosystem to enrich downstream life, and a richer stream life means a better environment for salmon.

In four out of the six study systems, allowing more salmon to spawn will not only help bears and the terrestrial landscape but would also lead to more salmon in the ocean. More salmon in the ocean means larger harvests, which in turn benefits fishers. However, in two of the systems, helping bears would hurt fisheries. In these cases, the researchers estimated the potential financial cost—they looked at two salmon runs on the Fraser River, B.C., and predicted an economic cost of about $500,000 to $700,000 annually. This cost to the human economy could help support locally threatened grizzly bear populations, they argue.

While these fisheries are certified as sustainable by the Marine Stewardship Council (MSC), the researchers suggest that the MSC principle that fisheries have minimal ecosystem impact might not be satisfied if the fishery is contributing to grizzly bear conservation problems.
The researchers believe the same analysis can be used to evaluate fisheries around the world and help managers make more informed decisions to balance economic and ecological outcomes.

What do grizzlies eat in northwestern BC ?

The current study and previous studies track the grizzly’s diet by studying the nitrogen and carbon istopes in grizzly hair. In one study in the early part of this decade, the BC Ministry of the Environment used guard hairs from “passive hair snags” as well as samples from bears killed by hunters or conservation officers.

The 2005 study says “Guard hairs are grown between late spring and fall, thus integrating the diet over much of the active season of temperate-dwelling bears.” Analysis of the isotopes can show what the bears ate over the season.

The study identified four elements in the grizzly diet across British Columbia, Alaska, Yukon and the Northwest Territories: plants, “marine-derived nutrients” mostly salmon, meat (primarily from ungulates such as moose) and in inland areas, kockanee salmon.

As could be expected, grizzly salmon consumption is highest in coastal areas. Males generally consume more salmon than females, likely because a mother grizzly may avoid taking salmon if there is danger to the cubs from males. The further inland a grizzly is found, salmon is a lesser factor in the bear’s diet. In Arctic regions, grizzlies can feed on arctic char, whales, seals and barren-ground caribou.

So what do local grizzlies eat? (excerpts from the 2005 study, Major components of grizzly bear diet across North America, National Research Council Research Press published March 28, 2006)

Map of grizzly diet and salmon — Grizzly consumption of salmon on the northwest coast (NRC)

North Coast 54.54 N 128.90 W (north and west of Kitimat)
Plants 33 per cent Salmon 67 per cent

Mid Coast 52.50 N 127.40 W (between Bella Bella and Ocean Falls)
Plants 58 per cent Salmon 42 per cent

Upper Skeena Nass 56.80 N 128.80 W
Plants 71 per cent Salmon 5 per cent Meat 13 per cent

Bulkley Lakes 54.10 N 127.10 W
Plants 63 per cent Salmon 6 per cent Meat 16 per cent Kokanee 15 per cent

Cranberry 55.40 N 128.40 W (near Kiwancool)

Plants 30 per cent Salmon 17 per cent Meat 40 per cent Kokanee 13 per cent

Khutzeymateen 54.68 N 129.86 W (near Prince Rupert)
Plants 22 per cent salmon 78 per cent

###

Other authors of the 2010 study are Chris Darimont, UCSC, Misty MacDuffee Raincoast Conservation Foundation, Denny Island, BC; Marc Mangel, Paul Paquet, UCSC and University of Calgary, Christopher Wilmers, USCC
Funding: This work was funded by an NSF GRF and Cota-Robles Fellowship (TL), a NSERC IRDF (CTD), the Wilburforce and McLean Foundations, and Patagonia. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

2005 study by Garth Mowat Aurora Research Crescent Valley BC and Douglas Heard BC Ministry of the Environment, Nelson

BC 2012 halibut quota drops 8 per cent, as Canada protests devastation caused by pollock trawl in Gulf of Alaska “nursery”

The International Pacific Halibut Commission has recommended a Canadian harvest quota for the 2012 season of 7.038 million pounds of halibut, a decrease of eight per cent from the 2011 quota of 7.650 million pounds.

The Department of Fisheries and Oceans has yet to confirm the quota but it routinely follows the IPHC recommendation.

The reduction was not as bad as first feared. The commission staff were recommending a B.C coast quota of 6.633 million pounds, a decrease of 16 per cent.

The overall harvest quota decrease for the Pacific coast is 18.3 per cent, due to continuing concerns about the state of the halibut biomass.

The 2012 halibut season is much narrower, opening on March 17 and closing on November 7. The commission says the March 17 opening day was chosen because it is a Saturday and will help the marketing by both commercial and recreational fishers. The earlier November date will allow better assessment of the halibut stock after the 2012 season, according to an IPHC news release. (In Canada, DFO closed the recreational season much earlier than the date recommended by the IPHC, in September, while allowing the commercial harvest to continue.)

In the release following the annual meeting in Anchorage, Alaska, last week, the IPHC said

The Commission has expressed concern over continued declining catch rates in several areas and has taken aggressive action to reduce harvests. In addition, the staff has noted a continuing problem of reductions in previous estimates of biomass as additional data are obtained, which has the effect of increasing the realized historical harvest rates on the stock. Commission scientists will be conducting additional research on this matter in 2012….

The Commission faced very difficult decisions on the appropriate harvest from the stock and recognized the economic impact of the reduced catch limits recommended by its scientific staff. However, the Commission believes that conservation of the halibut resource is the most important management objective and will serve the best economic interests of the industry over the long term. Accordingly, catch limits adopted for 2012 were lower in all regions of the stock except Areas 2A (California, Oregon and Washington) and 2C (southeastern Alaska)

Pollock trawl bycatch crisis costs Canada $7 million a year

In the bureaucratic language of the IPHC, “The Commission expressed its continued concern about the yield and spawning biomass losses to the halibut stock from mortality of halibut in non-directed fisheries.”

The IPHC says that British Columbia has made “significant progress” in reducing bycatch mortality and that quotas for vessels for other fish are being monitored, in California, Oregon and Washington have also had some success in reducing bycatch mortality.

It says that “Reductions have also occurred in Alaska, and new measures aimed at improving bycatch estimation, scheduled to begin in 2013, will help to refine these estimates.”

That phrase apparently masks a major problem of bycatch in the halibut nurseries off Alaska.

Craig Medred writing in the Alaska Dispatch in Should Alaska have protected halibut nursery waters noted that the Canadian delegation took a strong stand at the meetings:

Canada has protested that something needs to be done about the trawl industry [mostly for pollock] killing and dumping 10 million pounds of halibut off Alaska’s coast, but the International Pacific Halibut Commission proved powerless to do anything about it.
Meeting [last] week in Anchorage, the commission recognized the trawl catch as a potential problem, but then placed the burden of conservation squarely on the shoulders of commercial longliners along the Pacific Coast from Alaska south to California. The Commission again endorsed staff recommendations to shrink the catches of those fishermen in an effort to avoid an ever-shrinking population of adult halibut.

(This wasn’t reported in the Canadian media despite the importance of halibut both commercial and recreational to the economy of British Columbia. No Canadian media covered the IPHC conference in Alaska, despite the fact that halibut was a major issue in BC in the last federal election)

Medred’s report in the Alaska Dispatch goes on to say that the scientists say the Pacific Ocean is full of juvenile halibut, but that the juveniles seem to be disappearing before they reach spawning age (when the halibut reaches about the 32 inch catch minimum). “How much of this is due to immature fish being caught, killed and wasted by the billion-dollar pollock trawl fishery — which is in essence strip mining the Gulf of Alaska — is unknown.”

Medred says, “Scientists, commercial halibut fishermen and anglers all believe the catch is under-reported. Advisers to the commission — a U.S.-Canada treaty organization — indicated they are beyond frustrated with the bycatch issue.”

The official IPHC Bluebook report to the annual meeting said: “Not all fisheries are observed, therefore bycatch rates and discard mortality rates from similar fisheries are used to calculate bycatch mortality in unobserved fisheries.”

The official report to the IPHC gives one reason that the bycatch in Canadian waters is not as big a problem, the Department of Fisheries and Oceans ongoing monitoring of almost all commercial fisheries for bycatch.

But Canada is not satisfied with that and has submitted a formal proposal to the Commission to designate the Gulf of Alaska, “‘an area of special concern.” because the halibut that spawn in the Gulf of Alaska migrate to coastal British Columbia.

The Alaska Dispatch report says that the Canadian delegation told the IPHC: “Canada should not and must not be penalized for uncontrolled bycatch in other regulatory (areas), which IPHC staff have indicated could be costing (Canada) approximately 1 million pounds of lost yield in each year based on current, and what Canada believes may be questionable, estimates of bycatch.”

Medred says that one million pounds of halibut equals a loss of $7 million to Canadian fishermen alone.

IPHC news release, Jan. 31, 2012 (pdf)

International Pacific Halibut Commission confirms 18 per cent cut in overall quota for 2012

According to Alaska media reports, the International Pacific Halibut Commission, meeting in Anchorage, has confirmed an over all cut in Pacific halibut harvest quota of 18 per cent, or 7.5 million pounds for 2012.

KMXT, an NPR station in Kodiak, Alaska reports

Area 3A, the Gulf of Alaska will experience a 17-percent reduction from last year. That results in a 11.9-million pound catch limit, down 2.4-million pounds.

Area 3B along the Alaska Peninsula southwest of Kodiak Island, the reduction is the same 2.4-million pounds, but the percentage reduction is 32 percent, down to just over 5-million pounds. In Area 4A, the eastern Aleutians, the cut is 35 percent.

The only areas that did not get reductions were off the Washington coast in Area 2A, which will get a 9-percent increase, and Area 2C in Southeast Alaska, which will get a 13 percent bump, up almost 300,000 pounds.

There are no figures in the Alaska reports for British Columbia and no news on the International Pacific Halibut Commission website.

Recreational halibut quota buy-in program had “limited success:” DFO report to IPHC

A report prepared by the Department of Fisheries and Oceans for this week’s meeting of the International Pacific Halibut Commission in Anchorage says the controversial program where recreational fishers could buy quota from commercial fishers had only “limited success…with few pounds caught.”

The report also says that Fisheries Minister Keith Ashfield will be making a “decision on any changes to the current allocation plan in advance of the 2012 fishing season.”

The IPHC report says:

For the 2011 season only, DFO implemented an experimental leasing program, where interested recreational fishers could receive experimental licenses that would allow them to lease halibut quota from commercial quota holders and allow continued sport fishing after the general sport fish closure. The program allowed for a market-based transfer system and provided the recreational sector access to fish outside their management allocation. The program had limited success with 4,000 pounds transferred with few pounds caught.

Later in the report, the IPHC says that DFO did not release to the commission the exact figures for halibut caught under the pilot project.

According to the report, once again the recreational catch exceeded its assigned quota. DFO provided a preliminary 2011 sport catch estimate of 1.220 million pounds, which exceeded the sport fishery allocation by 272,000 pounds (29%). Canada overall also exceeded its halibut quota. The report says “The total Area 2B catch of 7.87 million pounds was 3% over the combined total catch limit (7.65 million pounds).” The commercial fishery came in slightly under quota, “less than one per cent,” according to the report. Any difference can be allocated to the First Nations Food, Social and Ceremonial Fishery.

The IPHC says that DFO anticipated the controversial early closure of the recreational fishery. The report says: “The season was the shortest on record, opening on March 1 and closing on September 5. In August, DFO projected that the sport allocation would be reached before the usual December 31 season closing date, so an early closure was not unexpected.”

Although there are no figures to prove it, it is likely the decision by the recreational fishers to boycott the program was one reason for the “few pounds” caught as part of the pilot project.

The pilot project announced a year ago, and only for 2011, was intended by DFO as pilot project to get additional quota for recreational halibut fishers and guides from the commercial fishery. The announcement, however, brought anger and demonstrations across British Columbia by the recreational fishery. The halibut allocation dispute was a key issue in most BC coastal ridings during the May election, but wasn’t decisive enough to defeat Conservative candidates such as John Duncan in Vancouver Island North, who kept his seat in a very close vote.

The IPHC opens its annual meeting on Tuesday, January 24, 2012, and concludes on Friday, January 27. The IPHC meeting will also consider recommendations for drastic cuts in halibut quotas all along the western coast of North America for the 2012 season, due to uncertainty about the long term health of the biomass.

The IPHC recommends a total west coast quota of 33.135 million pounds for 2012, a decrease of approximately 19% from 2011. The recommended season will run from March 15 to November 15. It says “This recommendation is a compromise between minimizing interceptions of migrating fish and providing opportunity for market presence of fish wild halibut.”

The proposed quota for British Columbia area 2B is 6,633,000 pounds, down 13.3%. The IPHC staff paper recommends that current Canadian policy of 88 per cent for commercial and 12 per cent for recreational halibut be continued. Recreational fishers and guides have objected to that quota for the past several years.

One of the major problems facing the halibut fishery along the west coast, according to the report, is the large number of undersized females in the total biomass. Any large catch of immature females would have drastic long term consequences on the halibut stock and therefore the halibut fishery.

A staff paper to be considered at the meeting calls for reconsideration of the minimum allowable size, balancing a suggestion to catch more immature males while maintaining the female stock until it can mature and produce a new generation.

Any announcement of a new Canadian policy by Fisheries Minister Keith Ashfield will be based on a 2011 long review of the Pacific halibut allocation that looked at the long-term options for allocation with objectives of conservation, economic prosperity, and flexibility. The review process included meetings with policy makers, stakeholders, and sector representatives.

You can retrieve the complete IPHC Annual Meeting Blue Book here.

Alaska governor meets with three energy CEOs to push North Slope LNG exports to Asia

Alaska Governor Governor Sean Parnell met with the chief executive officers from BP, ConocoPhillips and Exxon Mobil on January 5, 2012, to discuss alignment between the three companies on commercializing the North Slope’s vast natural gas reserves.

A news release from the governor’s office says Parnell asked “the three companies – the major lease holders for natural gas reserves on the North Slope – to work together on developing a liquefied natural gas (LNG) project that focuses on exporting Alaska North Slope gas to Asia’s growing markets.”

The release says that governor is targeting LNG exports to Asia to serve the growing demand for natural gas. That would make an Alaska LNG export terminal a rival to the three projects at Kitimat and another proposed project in Oregon.

Parnell and the CEOs – Bob Dudley of BP, Jim Mulva of ConocoPhillips and Rex Tillerson of Exxon Mobil – met for two hours. During the meeting, the governor’s release says, the CEOs briefed the governor on the extensive work they’ve been doing in response to his request. After meeting with the governor, the three CEOs briefed members of the Alaska state legislature.

Alaska governor meets with Energy CEOs — Governor Sean Parnell met in Anchorage Jan. 5, 2012, with the chief executive officers from BP, ConocoPhillips and Exxon Mobil to discuss alignment between the three companies on commercializing the North Slope’s natural gas reserves.(Alaska governor's office)

“I appreciate the willingness of the chief executives to come to Alaska to discuss the important topic of commercializing North Slope gas,” Parnell said. “For a gas project to advance, all three companies need to be aligned behind it. This meeting is an important step, but much work remains.”

The Associated Press reports that Parnell wants the companies to unite under the framework of the Alaska Gasline Inducement Act, which gave TransCanada Corp. an exclusive state license to build a pipeline and up to $500 million in state incentives.

AP says TransCanada has been working with Exxon Mobil to advance the project but has yet to announce any agreements with potential shippers.

TransCanada has focused most of its attention on a pipeline that would deliver gas to North American markets through Alberta to Canada and the Lower 48 states. TransCanada has also proposed a smaller pipeline that would allow for liquefied natural gas exports through a terminal at the oil export port of Valdez. A rival project, a joint effort of BP and ConocoPhillips that also would have gone through Canada, folded last year.

The Alaska Journal of Commerce reports BP and ConocoPhillips believe a major liquefied natural gas project is the best option for marketing North Slope gas, quoting the chief executive officers of the two companies Robert Dudley of BP and James Mulva of ConocoPhillips.

“Given the outlook with shale gas in the Lower 48, it looks like LNG has the best potential. We’re not saying the pipeline (to Canada) is impossible,” but a pipeline to southern Alaska to an LNG plant appears to have the best prospects, BP CEO Dudley told reporters following the meetings with Parnell and legislators.
ConocoPhillips’ Mulva agreed with Dudley. “We believe LNG is the best alternative for North Slope gas, far better than any alternatives,” Mulva said.

International Halibut Commission recommends drastic cuts in quotas, with worse to come

Environment Fishery

The International Pacific Halibut Commission is recommending drastic cuts in quotas along the west coast for the 2012 season and possibly even larger cuts for the 2013 season.

For area 2B, the coast of British Columbia, the IPHC is recommending an overall quota of 6.633 million pounds, down from 7.650 million pounds in 2011, a decrease of 13.3 per cent.

Along the entire Pacific Coast, the IPHC wants the total harvest cut 19 per cent from 41.07 million pounds this year to 33.882 million pounds in 2012.

The recommendations are based on the IPHC’s studies of the 2011 halibut harvest.

The commission says that exploitable biomass of halibut continues to decline, reflecting lower recruitment (the number of fish that are becoming harvestable) from the 1989 to 1997 year classes and smaller size at age.

The commission says that while recruitment from more recent year classes is stronger but halibut size at age continues to be much lower than that seen in the recent period (1997-1998) of historic high biomass, so these year classes are recruiting to the exploitable biomass more slowly than past year classes.

The IPHC FAQ explains this in easier terms as

For a simple question, this has a bit of a complicated answer. The simple answer is, they are still here. Or at least the same age fish are still here. For the past 15 years or so, halibut growth rates have been depressed to levels that haven’t been seen since the 1920’s. Both females and male halibut have the potential to grow rapidly until about age 10, about 2 inches per year for males and 2.5 inches for females. Thereafter, females have the potential to grow even faster, while males generally would slow down relative to female growth. Growth rates for these larger fish in the last 10 or so years are more on the order of one inch or less per year. This translates into a much smaller fish at any given age. There was a dramatic increase in halibut growth rates in the middle of this century, especially in Alaska. Sometime around 1980, growth rates started to drop, and now Alaska halibut of a given age and sex are about the same size as they were in the 1920’s. For example, in the northern Gulf of Alaska, an 11-year-old female halibut weighed about 20 pounds in the 1920’s, nearly 50 pounds in the 1970’s, and now again about 20 pounds. The reasons for both the increase and the decrease are not yet known but may be tied to increased abundance of other species, such as arrowtooth flounder, and availability of food supply

Steve Hare, the commission’s chief scientist told the Alaska Dispatch that scientists are becoming uncomfortable with the model they are using to calculate the biomass because “season after season the numbers of dead fish don’t add up correctly.”

Hare told the Alaska Dispatch that the commission is considering a new model that could mean “staggering cuts of 63 percent in the halibut fisheries to a mere 15 million pounds” in 2013.

Halibut quotas have been cut half since 2001 and the Alaska Dispatch says: “the implications of such a cut are huge — not only for fishermen of all sorts, but for small coastal communities from British Columbia north through Alaska, and for consumers.”

The quotas will be finalized and confirmed at the IPHC annual meeting in Anchorage, Alaska, during January 24-27, 2012.

IPHC news release Dec. 2, 2011 (pdf)

US Coast Guard seizes “stateless” drift net boat off Alaska: AP

Fishery

Associated Press reporter Becky Bohrer in Juneau reports on the Bangun Perkasa a rat-infested illegal fishing boat with a 10 mile long drift net seized off Alaska.

Seized Vessel Shines Light on Illegal Fishing

The recent seizure of a stateless ship in international waters 2,600 miles off Alaska’s coast has spotlighted the challenge that the U.S. and other nations face in trying to crackdown on illegal fishing, an activity that accounts for up to $23.5 billion a year in global economic losses.

Finding rogue vessels in the vast, open ocean can be like finding a needle in a haystack. But U.S. officials and some environmentalists say progress is being made, including multinational patrol and enforcement agreements and the potential for sanctions against countries that engage in illegal, unreported and unregulated (or IUU) fishing.

Seattle cod trawler wastes 114 tons of Alaska halibut: Alaska Dispatch

Environment Fishery

The Alaska Dispatch reports that a Seattle cod trawler wastes 114 tons of Alaska halibut

The Seattle-based trawler Alaska Beauty recently had a great week of halibut fishing… Only one problem: Alaska Beauty wasn’t supposed to be fishing halibut; it was supposed to be fishing cod.

Despite that, 43 percent of its catch was halibut. All of that halibut, by law, must be dumped back into the sea. Most of it goes back dead. Some Alaskans are starting to get angry at this sort of large “by-catch” of halibut by Pacific Northwest and Kodiak-based trawlers at a time when the species’ stocks are declining, and Alaska charter and commercial longline fisheries are locked in a bitter battle over every flatfish.

An anonymous blogger who goes by the name of Tholepin says “228,800 pounds of halibut wasted by draggers just last week,” Tholepin notes in the latest post. “Value? In cash terms to longliners, about $1.6 million. In lost reproductive potential, in lost growth potential, in long-term resource damage; all unknowns ..

Salmons’ extra large guts are a survival tactic

Image via Wikipedia

Environment Fishery Science

Salmon have extra large guts–up to three times larger than its body would suggest–that help it survive, scientists at the University of Washington say.

The study “Excess digestive capacity in predators reflects a life of feast and famine” is published in Nature.

A news release from the university calls the large gut a “previously unrecognized survival tactic.” Although fishers who gut a salmon may say that no one noticed how big the gut actually was as they threw it away, the same apparently applied to scientists as the article states: “Despite …basic principle of quantitative evolutionary design, estimates of digestive load capacity ratios in wild animals are virtually non-existent.”

The study is by PhD student Jonathan “Jonny” Armstrong, originally from Ashland, Ore, who says he has been fascinated by salmon ever since he saw a Chinook leap out of the water when he was ten.

The study says that when the “foraging opportunities for animals are unpredictable, which should favour animals that maintain a capacity for food-processing that exceeds average levels of consumption (loads), The study that piscine [fish] predators typically maintain the physiological capacity to feed at daily rates two to three times higher than what they experience on average…”

“This much excess capacity suggests predator-prey encounters are far patchier – or random – than assumed in biology and that binge-feeding enables predators to survive despite regular periods of famine,” Armstrong said. Co-author and supervisor on the paper is Daniel Schindler, University of Washington professor of aquatic and fishery sciences.

“Guts are really expensive organs in terms of metabolism,” Armstrong said. For instance, maintaining a gut can require 30 to 40 per cent of the blood pumped by an animal’s heart.

Some animals have some capacity to grow or shrink their guts in response to changing conditions. For example, according to previous studies, the digestive organs of birds that are about to migrate expand so they can eat more and fatten up. This is followed by a period when their guts atrophy and then, freed of the baggage of heavy guts, the birds take off. But this study shows that many fish species maintain a huge gut, which enables them to capitalize on unpredictable pulses of food.

Ravens and crows, for example, are known to cache food far from where they find it. Fish can’t do that. “Unlike some other animals, fish can’t just hoard their food behind a rock in the stream and eat it later. They need to binge during the good times so that they can grow and build energy reserves to survive the bad times,” Armstrong says.

Armstrong is part of the university’s School of Aquatic and Fishery Sciences which has a field site at the Alaska Salmon Program’s Lake Aleknagik. Using a dry suit, Armstrong snorkeled the Aleknagik tributaries, swimming in waters as low as 5°C where he found out the Aleknagik streams exhibited tremendous variation in water temperature, which inspired him to study how those temperatures affected the ecology of the streams.

In his initial studies, he looked at the effect of water temperature on juvenile coho’s ability to consume sockeye eggs. He says, “In cold streams, juvenile coho salmon were too small to fit the abundant sockeye eggs in their mouths. In warmer streams, the coho grew large enough to consume eggs, gorged themselves, and achieved rapid growth, and this suggested that small changes in temperature can have disproportionate affects on coho salmon production.”

The “previously unrecognized survival tactic” might apply to other top predators, such as wolves, lions and bears, Armstrong says.

US extends deadline for comments on Alaska halibut closure

The United States National Marine Fisheries Service has extended the deadline for comments on its controversial Halibut Catch Sharing plan by 15 days until Sept. 21.

The NMFS made the announcement in a news release on Sept. 1.

There was increasing political pressure on the service to take another look at the proposal, which like parallel cutbacks along the British Columbia coast are raising fears of economic damage to the recreational halibut sector. In Canada, the Department of Fisheries and Oceans has closed the recreational halibut season as of midnight, Sept. 5.

The Seattle Times reported Sept. 1, “Rep. Craig Johnson, R-Anchorage, said the halibut-allocation plan proposed by the National Marine Fisheries Service, which could cut the bag limit for charter-boat anglers from two to one halibut, could have a tremendous impact on Alaska coastal communities that depend on tourism connected to sport fishing.”

In the news release, Natinal Atomspheric and Ocean Administration, the department that governs the NMFS, said.

The decision to extend the comment period comes following a visit to Alaska last month by NOAA Administrator Dr. Jane Lubchenco, who attended a luncheon in Homer with U.S. Senator Mark Begich to hear concerns and comments about the draft plan first hand from both charter and commercial halibut fishers.

“Alaska fisheries have been among the healthiest and most sustainable in the world, and we are working to keep them that way for both recreational opportunities and the long-term economic benefit of Alaska fishermen and fishing communities,” said Dr. Lubchenco.

“During my recent trip to Alaska, I was honored to visit communities where the local economy is tied to the halibut fishery. I listened to the community’s concerns and I want to make sure that everyone has a chance to provide input in this public process of shaping the final halibut catch sharing plan.”

“While we need a plan to keep all segments of the halibut fishery within catch limits to sustain and rebuild the stocks, charter fishermen raised several legitimate issues at the Homer meeting warranting further consideration,” Sen. Begich said. “While many fishermen have already submitted comments, this extension will allow additional time for fishermen still out on the water to make sure they are heard. I am pleased Dr. Lubchenco is taking action and responding to the comments we heard when we spoke to the Homer Chamber of Commerce.”

NOAA says that the halibut stock in southeast Alaska and the central Gulf of Alaska has seen a steep decline in the past several years.

The agency claims the proposed catch sharing plan is designed to foster a sustainable fishery by preventing overharvesting of halibut and would introduce provisions that provide flexibility for charter and commercial fishermen. It adds that the catch sharing plan “was shaped through an open and public process through the North Pacific Fishery Management Council, which recommended the rule to establish a clear allocation between the commercial and charter sectors that fish in southeast Alaska and the central Gulf of Alaska.”

However, in protest meetings and letters to local media, the charter and recreational fishers in the state are saying that the council is dominated by the commercial interests and has been unfair to the charter and recreational fishery.