Whales

Scientists have known that humpback whales have a trick or two when it comes to finding prey at the bottom of the ocean, but how they locate a meal at night with little or no light has remained a mystery.

A new study has analyzed the importance of specific auditory cues that the creatures emit as they search the deep ocean for prey. 'Humpback whales are known to cooperate with others to corral prey near the surface,' said Professor Susan Parks of Syracuse University. “Recent studies suggest they may cooperate [with each other], when feeding on bottom prey, as well”, she added.

About 50 baleen whales live in an underwater canyon off the Florida Panhandle, making them the only resident baleen whales in the Gulf of Mexico, have long been classified as Bryde's whales. Several other baleen species visit the Gulf, but this group is the only one known to live there year-round and new tests have now shown that these whales are unlike any other of their species. Their genetic makeup makes them different enough to be considered a distinct subspecies of Bryde's — or a new species altogether.

In a world-first, the public is getting the opportunity to assist monitoring shark movements off the Western Australia coast in a bid to reduce the number of attacks. The Department of Fisheries has updated its Sharksmart website, which will digitally map all reported shark sightings from the public, surf lifesavers and other agencies.” We want to give beachgoers the latest information so they can make informed decisions about their water use," said Lisa Clack, manager of the department's shark response unit.

A new study in the journal Plos One has revealed blue whales assemble for long periods in the busy shipping lanes off California, raising concerns about collisions between vessels and the endangered cetaceans.

“It’s an unhappy coincidence,” said study leader Ladd Irvine, a marine mammal ecologist at Oregon State University. “The blue whales need to find the densest food supply. There’s a limited number of those dense places, and it seems as though two of the main regular spots are crossed by the shipping lanes.”

The animals tagged for this study exhibited profound diving capabilities; however, the dive depths and durations reported here far exceed the prior records for this species. The deepest dive of 2992 m.

Diel patterns in dive behaviour were strongly evident in this dataset, confirming previous observations from short overnight deployments that this whale spends significantly more time in waters above 50 m at night than they do during the day.

Researchers from the British Antarctic Survey found that although female humpback whales have crossed from one hemisphere to another at certain times in the last few thousand years, they generally stay in their ocean of birth.

This isolation means they have been evolving semi-independently for a long time, so the humpbacks in the three global ocean basins should be classified as separate subspecies. This has implications for how we think about their conservation and recovery on a regional scale.

“Further genetic sequencing and analysis should also help us to understand more about the pattern of humpback migrations in the past. Big changes in the ocean can leave signatures in the genetic code of marine species. For example, the last glacial maximum caused many to shift southwards until the ice retreated or to find ice-free areas in the north.

Humpbacks are excellent oceanographers; they go where the food is and can travel long distances to get it, so their patterns of past migration can tell us a lot about the ocean thousands of years ago.”

The researchers used a combination of DNA analysis and physical characteristics to identify the new species from seven specimens found stranded in Sri Lanka, the Gilbert Islands (now Kiribati), Palmyra Atoll in the Northern Line Islands near Hawai'i, the Maldives, and the Seychelles.

The first specimen was a female found washed up on a Sri Lankan beach more than 50 years ago. At the time the National Museums of Ceylon, P.E.P (Paulus) Deraniyagala, described it as a new species, and named it Mesoplodon hotaula, after the local Singhala words for 'pointed beak'.