Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Solid management, natural resilience both key to sockeye success

12.05.2003


The resilience of sockeye salmon runs in Alaska’s Bristol Bay -– after a century of fishing they’re as healthy as they’ve ever been – is about strength in numbers.



It’s not just an abundance of fish, although the numbers returning to spawn is tens of millions more than the total across the lower 48 states and prudent actions by fishermen and the Alaska Department of Fish and Game have helped make it a classic example of a sustainable fishery.

As it turns out, it’s also about having a large number of population segments, or components, the fish in each programmed to breed and thrive under conditions somewhat different from the fish in other components, University of Washington researchers report in this week’s Proceedings of the National Academy of Sciences.


It’s an important natural buffer in the face of changing environmental conditions, particularly those affected by climate, that can make winners out of seemingly insignificant components of the population, or stock, while dwarfing the once mighty.

Salmon managers in the Pacific Northwest and elsewhere, as well as those overseeing other fish and shellfish populations, need to consider this biocomplexity within a species, say the UW’s Ray Hilborn, Thomas P. Quinn and Donald Rogers, all professors of aquatic and fishery sciences, and Daniel Schindler, associate professor of biology. The loss of biocomplexity is a characteristic of salmon in the Pacific Northwest, where many stock components were lost because of dams or deliberate overharvesting in an attempt to maximize catch from hatcheries, the authors say.

It’s why protecting only the habitat and fish of today’s strongest runs is a mistake. One can’t know for sure which runs might “stumble” in the future, Quinn says.

Sockeye is one of four species of salmon found on the West Coast and in Alaska. It is most different from the other species because the young spend a year, sometimes more, in freshwater lakes before heading to sea. Alaska’s Bristol Bay sockeye has traditionally been the most valuable salmon fishery in the world, at its height worth $200 million to $400 million and, with today’s prices, worth between $30 million and $50 million.

In work funded by the National Science Foundation, the Bristol Bay salmon processors and the University of Washington, the scientists looked at the shifting fortunes of the salmon in the three Bristol Bay fishing districts, each with its distinct network of rivers and lakes. Through the 1950s, ’60s and mid ’70s, when conditions tended to be cooler and drier because of the influence of the Pacific Decadal Oscillation, the Naknek and Kvichak network far exceeded the other two districts. The dominant contribution was from Lake Iliamna, the United State’s largest lake behind the Great Lakes.

In 1977-78 the Pacific Decadal Oscillation switched to a different phase leading to warmer and wetter conditions with higher water levels and flows among the results. The productivity of the three fishing districts began shifting in response, Hilborn says.

Today Lake Iliamna contributes so few fish that it requires special protective management. The Egegik network, which feeds another of the fishing districts studied and which earlier accounted for a mere 5 percent of the catch, expanded greatly until the ’90s when the third fishing district, the Nushagak, increased. In some recent years, the Nushagak has been the most important fishery in Bristol Bay. "In the 1950s, managers could have chosen to overlook the Egegik or Nushagak systems, and at the time the cost would have appeared to be low," the authors write.

The Bristol Bay sockeye stock is an amalgamation of several hundred discreet populations, or components. It’s all those local adaptations that stabilize the system, Quinn says. The advantage goes to deeper-bodied males when fighting for places to spawn and attracting females, until one considers what happens when streams run lower than usual. Then those deeper-bodied males are more likely to become stranded and, because they stick up higher out of the water, are easier for hungry bears to bite than males in the components of the stock that have average, or even smaller-than-average, body depths.

Egg size, preferred spawning sites, the size of young when hatched are among the many other adaptations that could give advantages depending on conditions.

"We buy insurance for the future by having networks of habitat and not just trying to save the habitat of today’s strongest runs," Schindler says. This might necessitate a much finer scale of management than is the current norm, the co-authors say.


For more information: Hilborn, (206) 543-3587, rayh@u.washington.edu; Quinn, (206) 543-9042, tquinn@u.washington.edu; Schindler, (206) 616-6724, deschind@u.washington.edu

For a copy of the article: Jill Locantore, PNAS, 202-334-1310, jlocantore@nas.edu

Sandra Hines | EurekAlert!
Further information:
http://www.washington.edu/

More articles from Ecology, The Environment and Conservation:

nachricht Scientists on the road to discovering impact of urban road dust
18.01.2018 | University of Alberta

nachricht Gran Chaco: Biodiversity at High Risk
17.01.2018 | Humboldt-Universität zu Berlin

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>