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Whales vs. Ships

March 26, 2013

Keeping them out of each other’s way is a complicated business:

A first-of-its-kind study matching whale habitat to Southern California shipping lanes shows that two species, humpback and fin whales, might suffer fewer ship strikes if a new lane were created.

But the solution is not quite so simple for blue whales. These giants of the sea appear to be in the most trouble from ship strikes, and would be unlikely to benefit from any change in the four shipping lanes the study considered.

The scientists who conducted the study also estimated that more blue whales are being struck off the Southern California coast than their population can sustain without raising the risk of depletion.

“At best, the blue whale population is remaining steady,” said Jessica Redfern, a marine ecologist at the National Marine Fisheries Service and the study’s lead author. “Of the three, we’re probably the most concerned about blue whales.”

All three species examined in the study are listed as endangered. The scientists used data on conditions in the marine environment, along with whale sighting records, to map out the most likely habitat for each species.

Four shipping routes were then superimposed over the habitat maps. The result: the clearest picture yet of the places on the Southern California coast where ships and whales are most likely to collide.

The findings reveal the intricate interweaving of ocean corridors used by humans and the massive sea mammals.

The route that presents the least risk to humpback whales, for example, poses the highest risk for fin whales. The reverse also is true.

Humpbacks tend to concentrate farther north, fins farther south.

“Something in the center there seems like it may be good for ameliorating the risks for both species,” Redfern said, though the study does not make specific recommendations about shifts in shipping lanes.

Blue whales, however, occur throughout the area along all four shipping routes, spread so evenly that concentrating shipping in any one of the four routes seemed unlikely to reduce their risk.

Here’s how it looks on paper:

Moving shipping lanes around, especially if it costs shipping companies money, is not an easy ask. Whales–dead or alive–don’t show up on a shipping company’s balance sheet. But shipping slowdowns and re-routing on the Atlantic coast have helped reduce some right whale deaths.

When whale populations are so fragile, and whales are so majestic and intelligent, each life saved is especially important. Shipping companies might resist, but they can pass the incremental cost on to customes. And if that induces people to buy less stuff shipped halfway around the world, then that’s not a bad thing, either.

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