Bryde’s Whales in Gulf May Be Critically Endangered

WASHINGTON (CN) – A tiny population of genetically distinct Bryde’s whales in the Gulf of Mexico has been proposed as an endangered subspecies under the Endangered Species Act. The National Resource Defense Council petitioned the National Marine Fisheries Service on behalf of the whales in 2014, asking for protection for a distinct population segment found in the northern region of the Gulf of Mexico.

“This subspecies of Bryde’s whale, found only in the Gulf of Mexico, will not survive without a concerted effort. An Endangered Species listing compels action and provides a plan to give these whales the best chance to endure. It’s going to be a challenge to keep them from going extinct, even with these protections. But this is a huge, and critically necessary, step forward to save these whales,” NRDC’s Marine Mammal Protection Director Michael Jasny said in response to the listing proposal.

Other populations of Bryde’s are found in many oceans of the world. Bryde’s whales, pronounced “brew-dahs” or “broo-das,” were named for a Norwegian whaler, Johan Bryde, who built the first whaling stations in South Africa. Bryde’s are large baleen whales that can grow up to 55 feet long, weigh up to 90,000 pounds, and are considered “great whales” or rorquals, the agency said. They are sleek, with dark grey upper bodies, white bellies and three distinctive ridges near their blowholes.

Recent genetic analysis found that the northern Gulf of Mexico population of these whales comprises a separate subspecies of Bryde’s, so the agency’s proposal to list the subspecies is based on this new taxonomic information, rather than the distinct population segment that was petitioned.

According to the 2014 NRDC petition, the NMFS estimated the population in the northern Gulf of Mexico to be around 33 whales, based on a 2009 survey. The listing proposal noted that Duke University researchers recently estimated the population to be 44 individuals based on averages from 23 years of survey data. Population estimates are based on aerial or ship-based line-transect surveys, but there is a “paucity of data,” the agency acknowledged.

This subspecies is found in a narrow corridor along the De Soto Canyon shelf break in the northeastern Gulf of Mexico, in waters that range between 100 and 300 meters (328 to 984 feet) in depth. The northern edge of the whales’ “biologically important area” (BIA) is roughly in line with Pensacola, Florida, and the southern edge is roughly in line with Tampa.

Though the Deepwater Horizon platform was not directly in the whales’ BIA, the historic spill, and the presence of thousands of other oil and gas platforms in the region is one of the top three out of 27 identified threats to these whales. The spilled oil and the dispersants used in the cleanup response can have “lethal or sub-lethal” effects on baleen whales, the agency said.

Human-caused, or “anthropogenic,” noise is another of the most severe threats. Large amounts of low-frequency noise from shipping, development and energy exploration activities interferes with the whales’ hearing and negatively impacts their ability to communicate, navigate, attract a mate, find food and avoid predators.

The third top threat is vessel strikes, due to the high volume of shipping traffic in the whales’ BIA. “The Bryde’s whales’ dive behavior contributes to their risk of collision. Tracking information indicates they spend the majority of the night within 15 meters of the surface. The risk of vessel strike is significant, given the location of commercial shipping lanes, the difficulty of sighting a whale at the surface at night, and the low ability of large ships to change course quickly enough to avoid a whale,” the agency said.

Although the whales are already listed under the Marine Mammal Protection Act, listing under the Endangered Species Act would provide additional protections. Any federal actions or activities that require federal permits or funding would need to undergo a consultation process with the NMFS. If critical habitat is found to be determinable and prudent, then a critical habitat designation would also require consultation. Listing also generates a recovery plan for the species.

Public comments on the listing proposal are due Feb. 6, 2017.  A public hearing is scheduled for Jan. 19, 2017 in St. Petersburg, Florida.

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