Endangered whales make a comeback, thanks to changes in shipping
North Atlantic right whales, the most endangered of New England’s whales, are making a modest comeback, according to New England Aquarium’s senior scientist Moira Brown. American efforts to protect the endangered species, however, appear to be less successful than Canada’s, Brown said last week in a speech sponsored by the Rhode Island Natural History Survey at the University of Rhode Island.
The current population of 450 North Atlantic right whales annually migrates from winter calving areas along the coast of Florida and Georgia to summer feeding areas near Cape Cod and Nova Scotia. The typical right whale is 50 to 60 feet long and weighs 60 to 70 tons.
Recovery of the species will be slow, Brown predicted, because female right whales do not give birth until they are nine years old – and then only produce one calf every three years under optimal conditions. In the 1980s, the closely observed species produced about 12 calves per year, Brown said, but that dropped to just one birth in 2000.
Since then, however, the whales have averaged 20 offspring a year, with a record 39 births in 2009.
“Something looks much better,” said Brown, who is also a senior scientist with the Canadian Whale Institute. Marine biologists have yet to pinpoint the cause of the baby boom, she added.
In the last three years, the U.S. and Canada have acted to reduce human-related whale deaths, although the impact of that action has yet to be reflected in the whale population figures. The leading causes of whale deaths, Brown said, are ship strikes, which account for half of all right whale deaths, and entanglement in fishing gear.
Unfortunately, whales’ principal food source – plankton – like deep-water basins, which are also ideal places for shipping channels. Nevertheless, Canadian efforts to reduce ship strikes have been highly successful, according to Brown, who has worked since 1985 to protect the mammal.
After ship strikes in the Bay of Fundy killed right whales in 1993, 1995 and 1997, Brown and others formed a working group with the shipping industry to address the problem. By moving shipping lanes 3.2 nautical miles southwest, the risk of vessel strikes was reduced 96 percent, Brown said.
Irving Oil, whose tankers regularly cross the bay, was particularly supportive of the move, she added.
In 2003 and 2006, a second problem area was identified as two whales were killed in collisions south of Nova Scotia. Using radio transmissions, scientists tracked ship traffic and learned that most boats avoid a key whale feeding area. Enough cross the area, however, to endanger the whales.
Again working with the shipping industry, scientists established a 980-square-nautical mile voluntary conservation area endorsed by the International Maritime Organization. In 2008, 70 percent of ships avoided the voluntary protection area. This year, compliance rose to 80 percent, Brown reported.
U.S. efforts haven’t worked as well, said Brown. In 2008, the National Marine Fisheries Service established seasonal low speed zones within 20 nautical miles of the East Coast to protect migrating whales. The zones, including the Great South Channel near Cape Cod, require ships to slow to 10 knots, but Brown said compliance is a disappointing 20 percent.
Canada achieved better results, Brown said, thanks to shipping industry cooperation and international support through the International Maritime Organization. The Canadian changes also increase voyage times far less than the American slow speed zones. Had Canada implemented a 10- knot zone rather than a voluntary conservation area, she said, trips would have been increased by two hours instead of 8.5 minutes.
Whales also die when entangled in fishing gear, Brown said – primarily the lines used to catch lobsters and ground fish. According
to studies, 75 percent of right whales have scars from entanglement and about 10 percent get entangled every year. In October 2008, the National Marine Fisheries Service required gill nets be designed to break when wrapped around whales.
Then, in April 2009, the federal agency required that weights be attached to lines that link lobster pots to prevent them from floating where feeding whales may pass.
Brown is the driving force behind protection measures, according to URI marine biology professor Robert Kenney, and she is optimistic about the right whale’s future.
“We have more protective measures in place than we have ever had,” Brown noted, cautioning that the results of U.S. speed limits and fishing gear provisions have yet to be measured.