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There are believed to be about 2,000 blue whales in the northeast Pacific, and about 10,000 worldwide. The largest animals on Earth, blue whales can grow up to 90 feet long, still a fraction of the size of cargo ships that can stretch 1,200 feet. There also are about 2,000 fin whales in the northeast Pacific, and about 2,500 humpbacks. While fin and humpback whales have seen gains in population since the 1990s, the number of blues has declined or remained flat. How many whales die from collisions each year isn't known because most accidents go undocumented and whales that are hit often sink. Whale researchers use population models that factor a species' reproductive rate and its natural mortality to come up with an estimate of how many are likely dying. In 2010 there were just five confirmed fatal collisions recorded in the area outside San Francisco Bay. But the number of actual strikes of all whale species is likely 10 times higher, Calambokidis said. PRBO Conservation Science, an environmental research group, conducts annual surveys of whales and other marine life in the sanctuaries around San Francisco Bay. Research director Jaime Jahncke said the number of blue and others whales is four to five times greater than in 2004, increasing the likelihood of ship strikes. These surveys and other data were used to help map the new shipping lanes by showing vessel owners and federal officials where the whale grounds and shipping lanes were overlapping. There currently are three shipping lanes coming in and out of San Francisco Bay. The westbound shipping lane currently ends at the relatively shallow continental shelf, where ships disperse. The new westbound lane would extend three miles past the continental shelf, and contain traffic to a defined area over the whale feeding grounds. The new northbound lane would also be extended miles beyond the shelf, keeping vessels sailing in a straight line for a longer time, rather than allowing them to disperse where the whales congregate. ___ Online: Whale mapping data: http://www.accessoceans.org/
[Associated
Press;
Reporter Jason Dearen can be reached on Twitter at https://twitter.com/JHDearen.
Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
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