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From Wildlife Extra:
New technology could save blue whales from being hit by ships
Scientists from the University of Maryland’s Center for Environmental Science are developing a near real-time computer model that predicts where endangered blue whales will gather as they move around the Pacific ocean off California, reports digital news site, TakePart.
Ultimately this technology will mean that ships can be notified of the presence of whales and the chances of a collision will be minimised.
Collisions with cargo ships are the primary threat to endangered blue whales. In 2007, four blues were killed, likely by ship strikes, in or near the Santa Barbara Channel.
In 2010, five whales, including two blues, were killed in the San Francisco area and elsewhere along the north-central California coast.
Scientists and the shipping industry have been looking for ways to reduce the number of collisions, but they have had little solid data on the whales’ whereabouts until now.
The project merges the past movements of satellite-tagged blue whales with current environmental conditions off the California coast that influence where the whales travel.
In 1993, Ladd Irvine, a marine mammal ecologist at Oregon State University’s Marine Mammal Institute, and his colleagues began fixing satellite tags to blue whales off the California coast.
By 2008, they had tagged 171 blue whales, which they watched swim to the Gulf of Alaska and the southern tip of Baja, Mexico. In the summer and early autumn, the whales returned to the California coast, feeding on krill before migrating south for the winter.
Near Los Angeles and San Francisco, shipping lanes crisscross these key feeding grounds.
“We got a nice detailed look of where the whales spend their time in US waters from year to year and the timing of when they are present and when they leave,” said Irvine.
“It happened that the two most heavily used areas were crossed by these shipping lanes.”
Most of the tags stayed with the whales for two or three months, but one whale held on to its transmitter for more than 500 days, giving the researchers a unique look at its annual route.
Whale No 3300840 followed its prey over the summer season and returned to several spots within a week of having been there the previous year.
Adding this data to satellite-monitored environmental data – including sea surface temperature, chlorophyll concentration (which reduced food for whales), and upwelling (where nutrient-rich waters move closer to the surface) – could reveal more precisely where and when blue whales will congregate along the shipping routes.
If the model forecasts a whale hot spot, ships could be rerouted or their speeds reduced to avoid collisions.
Helen Bailey, the marine mammal specialist leading the Maryland study, says this information is invaluable.
“We’ll be able to say, given the current conditions, what is a whale hot spot,” she said. “The hot spot might only coincide with the shipping lane a few months of the year. If the shipping lanes could be modified, it would reduce the risk of a whale strike.
“Only three can be killed per year to keep the population sustainable, and anytime we hear a number close to that is reason for concern because it’s probably a large underestimate.”
About 2,500 blue whales live in the North Pacific and another 500 in the North Atlantic. Estimates suggest the global population of blue whales is between 10,000 and 25,000.
Since 1900, the blue whale population has declined or remained flat, even though it is a protected species.
The results of the study are timely as the National Oceanic and Atmospheric Administration is currently planning a review of shipping lanes in the Southern California area.
“Having more information from the whale perspective helps NOAA look at the broader story to see if there is a way to reduce the risk of strikes,” said Monica DeAngelis, a marine mammal biologist at NOAA.
Commercial whaling was banned almost 30 years ago, but why hasn’t the world’s whale population recovered yet? Here.