Visitor Counter

hitwebcounter web counter
Visitors Since Blog Created in March 2010

Click Below to:

Add Blog to Favorites

Grizzly bears, black bears, wolves, coyotes, cougars/ mountain lions,bobcats, wolverines, lynx, foxes, fishers and martens are the suite of carnivores that originally inhabited North America after the Pleistocene extinctions. This site invites research, commentary, point/counterpoint on that suite of native animals (predator and prey) that inhabited The Americas circa 1500-at the initial point of European exploration and subsequent colonization. Landscape ecology, journal accounts of explorers and frontiersmen, genetic evaluations of museum animals, peer reviewed 20th and 21st century research on various aspects of our "Wild America" as well as subjective commentary from expert and layman alike. All of the above being revealed and discussed with the underlying goal of one day seeing our Continent rewilded.....Where big enough swaths of open space exist with connective corridors to other large forest, meadow, mountain, valley, prairie, desert and chaparral wildlands.....Thereby enabling all of our historic fauna, including man, to live in a sustainable and healthy environment. - Blogger Rick

Subscribe via email to get updates

Enter your email address:

Receive New Posting Alerts

(A Maximum of One Alert Per Day)

Wednesday, April 11, 2012

Seemingly self-evident, a recent University of California study on the impacts of Salmon on Grizzly Bear and Fisher populations revealed that the more Salmon that were left to "swim free" and not be harvested,,,,,,,,,,,,the better off the Bear and Fisher populations became,,,,,,,with psitive ripple effects through the ecosystems that the Bears and Fishers occupy

Swimming Salmon Benefit Grizzlies and Fisheries

By Cassie Ryan;
A fish in the stream could be worth two in the paw, according to a new model developed by scientists to study the effect of salmon migration on ecosystems and harvests.

Pacific salmon, Oncorhynchus spp., return to their natal streams to spawn and die, but are captured en route by grizzly bears and fishers. By increasing the number that escape upstream, known as "escapement," more salmon can breed, raising numbers in the ocean and thus long-term harvests for both bears and humans, which can benefit the environment.

"Salmon are an essential resource that propagates through not only marine but also creek and terrestrial food webs," said study lead author Taal Levi from the University of California—Santa Cruz (UCSC) in a press release.

According to Levi, North American Pacific salmon fisheries are mostly well managed with fish counted when they arrive in coastal streams to decide allocations for harvesting and spawning.

However, concerns that overharvesting could be depleting terrestrial and aquatic food webs led Levi's team to study the relationship between sockeye salmon, O. nerka, and 18 grizzly bear populations to ascertain how much of their diet consisted of salmon. Sockeye salmon runs are a highly regulated fishery of considerable economic significance in Alaska and Canada.

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

When there are plenty of salmon, bears prefer to eat the eggs and brain, which are rich in nutrients, leaving the carcass to enter the ecosystem, enriching terrestrial plants and life downstream. "Bears are salmon-consuming machines," Levi said. "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."

Of six systems studied, the four coastal ones showed that more spawning salmon produced more salmon in the ocean, as well as benefiting bears and their environment. However, in the other two, both inland on the Fraser River in Canada, allowing for bear conservation created a predicted loss of around $500,000 to $700,000 per year.

This is because coastal stocks are enriched by other salmon species, apart from sockeyes, whereas the runs of other species are small inland.

No comments: