Bears and spawning of salmon.

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THROUGHOUT THE MAJESTIC COASTAL FORESTS of the Pacific Northwest, spawning salmon and bears form one of the ecosystem’s most vital, nourishing relationships. Yet their keystone connection faces enormous threats. Salmon is the common name for several species of fish in the family Salmonidae. Other fish in the same family are called trout. The difference between salmon and trout is sometimes said to be that salmon migrate and trout are resident, and that salmon spawn once and trout spawn many times.

Wild salmon must survive overzealous fisheries and sea lice-infested farms. Brown and black bears suffer from habitat loss, sport hunting and other conflicts with humans. Both face the consequences of pollution and, increasingly, global warming. When salmon return to freshwater streams to spawn, their bodies carry precious nutrients from the sea, which bears unwittingly share with countless other species. Ultimately, as the relationship between salmon and bears degrades, so too does their shared ecosystem.

Salmon = Bears

Bear populations near the coast grow with salmon availability, and can be 80 per cent greater than in interior regions. For female grizzlies, body mass and the number of cubs they have also increase with the amount of salmon they eat. A healthy condition prior to hibernation is made possible because salmon arrive in late summer and fall, when fat accumulation becomes crucial. In addition to fasting through the winter, female bears need enormous amounts of energy to undergo gestation and feed their young. Recent research also shows that when salmon-dependent male grizzlies eat less they have higher levels of cortisol, a stress hormone known to suppress immune system function in mammals.

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