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Tuesday, March 2, 2010

Whales Suspected of Herring Population Shortage

Whales Suspected of Herring Population Shortage



Herring are small oily fish about 9inches in length who can be found in the waters of the North Pacific and North Atlantic Oceans. They play an extremely vital role in the oceanic food chain, serving their role as a major food source for animals like seabirds, dolphins, whales, sharks, sea lions, tuna, and other larger fish. Herring have also been used for food by humans since 3000BC and are still fished today. Needless to say, their absence would put a damper on aquatic life as well as our own on land.


Humpback whales have been suspected of bringing down the herring population in the Prince William Sound, Anchorage. The whales, which usually stop by in the summer, have been stopping by in autumn and feeding on vast amounts of newly born herring. They now thrive in an area that was once poisoned by 11 million gallons of crude oil in 1989. The oil came from the 987 foot Exxon Valdes, a supertanker that sprung a leak and wiped out much of the herring population in the area. In 1980, before the spill, record harvests of herring were recorded compared to 1993 when only 25 percent of the expected ad

ults returned to spawn. Some conservaton organizations have this to say about the herring population “The argument that increasing whale populations are behind declining fish stocks is completely without scientific foundation.”

This picture of a supertanker oil leak depicts the damage that crude oil spills can cause the ocean. Oil spills on top of peculiar humpback whale behavior have led to a scare in the herring world.

North Pacific humpbacks begin their annual migrations from the Gulf of Alaska in early fall. Humpbacks have recently been reported to be skipping their annual mating and birthing trips to places like Hawaii and Mexico. Most humpback whales make mammoth journeys every year between their feeding and breeding sites. ‘Because seasons are reversed either side of the equator, Northern and Southern Hemisphere populations of humpbacks probably never meet; those in the north travel towards their breeding grounds in tropical waters as those in the south are traveling towards the pole to feed, and vice versa.’

A recorded 199 whales were using the sound in Anchorage from September through March with as many as 129 there at one time. So what is the reason for these whales eating and migrating in such obscure ways?

Bibliography:

http://proquest.umi.com/pqdweb?index=2&did=1956955381&SrchMode=1&sid=1&Fmt=3&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1266595757&clientId=28082

http://fisherycrisis.com/DFO/bofwhales.htm#3

http://www.boston.com/news/nation/articles/2010/02/08/researchers_target_humpback_whales_in_herring_loss_study/

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=115x158505

http://www.whaleroute.com/migrate/

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