This Week in Whales: Dolphins Spend More Energy to Be Heard; Humpbacks No Longer Endangered?; Fishing Gear Traps Whales in PacNW...
Dolphins expend extra energy to get heard in noisier waters - A study released last week by NOAA's Northwest Fisheries Science Center and UC Santa Cruz found that dolphins expend extra energy to raise their voices to be heard in noisy environments. The study, which is one of the first to measure the biological costs to marine mammals trying to communicate over the sounds of ship traffic, found that a group of dolphins consumed about 80 percent more oxygen when whistling at the highest vocal energy levels than they did at rest. This "metabolic cost" may add up over time, especially for younger animals or nursing females. In an ocean that's only getting noisier, these findings don't bode well.
NOAA proposes delisting/reclassification of humpback whales - Is the humpback whale an Endangered Species Act (ESA) success story? NMFS thinks so: last Monday they released a proposal to divide the humpback whale into 14 distinct population segments and remove federal ESA protection from 10 of those segments. Of the remaining four segments, two would keep their endangered status and two would be relisted as threatened. I'm not so sure this is the right move - bycatch, ship strikes, and ocean noise still pose threats to the species. NRDC will be looking closely at the proposal.
Feeding off fishermen's lines = reproductive success for killer whales in the Southern Ocean -Last week, French researchers unveiled data showing that killer whales that feed off of fishermen's lines in the Southern Ocean are more likely to successfully deliver a calf the following year. The researchers compared ten years' worth of observations of a group of whales that learned to snatch fish off longlines with observations of a group that fed normally, and found that females who feasted upon the lines were four percent more likely to successfully deliver a calf the following year. Researchers found that even though killer whales only fed from longline fisheries at an average of two weeks each year, that extra nutritional boost still gave those pods a slight reproductive advantage. Four percent doesn't seem like a lot to me, but I'll take the scientists' word on it. These killer whales aren't the only population to figure out how to take advantage of a free buffet -- sperm whales in the Gulf of Alaska have also been spotted munching away at fishermen's lines.
Southeast Alaska companies agree to guidelines restricting boat activity during whale foraging - Last Thursday, NFMS launched Whale SENSE, a voluntary program for commercial whale-watching and fishing companies in southeast Alaska intended to reduce disturbances from boats when whales are foraging. The program, which builds off successes achieved in the Atlantic region, asks companies to operate boats at slow speeds around whales and limit the amount of time spent near feeding whales. Collisions between whales and whale-watching boats have risen as commercial whale-watching programs have grown in popularity, so here's hoping the program keeps whales - as well as their watchers - safe from harm. If not, we may have to make such restrictions mandatory.
Fishing gear entraps record number of whales this year - A record 25 whale entanglements along the West Coast have already been reported in the first four months of 2015, compared to 30 entanglements reported for all of 2014. Fishing gear set near the coastline catches whales as they migrate between Arctic feeding grounds and tropical breeding grounds, and the buoy lines and nets can cut into a whale's skin, impairing its ability to swim, feed, or get to the surface for breath. Advocates and NMFS biologists are looking into ways to reduce the bycatch count, by limiting the amount of time a net can remain in the water without being retrieved or installing improved fishing gear that breaks away when a whale gets snagged.
And this week in whale videos: a team of ocean scientists had a rare run-in with a curious sperm whale while operating a remotely operated underwater vehicle, or ROV, 2,000 ft beneath the Gulf of Mexico. Researchers of the Nautilus Exploration Program were using the ROV Hercules to monitor methane bubbles on the ocean floor when a juvenile sperm whale came upon the vessel and circled it several times. Watch the video below, and read more about the encounter on the Nautilus blog.
Meanwhile, this week in Wales...
Like the rest of the UK, Wales is gearing up for next week's general election. Good times.
This blog was written in large part by NRDC's Marine Mammal Protection Project's assistant, Julie Mendel. Thanks Julie!