Dolphins

The Mexican government has announced the successful conclusion of a project involving the placement of 193 cement blocks on the sea floor in strategic locations in the vaquita’s habitat.

Called the Concrete Block Planting project, the objective was to discourage the setting of gillnets within the Zero Tolerance Area, where the remaining vaquita population is localised. Large steel hooks protrude from the top of the blocks, trapping any gillnets they come into contact with.

In early October, after nearly three months, the 193rd block was finally placed on the sea bed.

Researchers have discovered that male bottleneck dolphins form long-term social groups to help one another find mates and fight off competitors.

It was the first time such behaviour was observed in the animal world.

Their conclusions were based on data collected of 202 Indo-Pacific bottlenose dolphins between 2001 and 2006 in Shark Bay, Australia, using visual and auditory data. In the lab, the researchers then focused on studying the interactions of 121 of individuals for the next decade.

Can hunting by echolocation be as fast as hunting by sight?

As visual animals, we may find this a peculiar question—not so if one applies it to animals that hunt using echolocation, like bats, dolphins and whales. These animals emit clicking sounds and use the reflected echoes to determine the location of objects and other animals.

Can animals that hunt using echolocation lock onto their prey and track their movements, and how fast can they react? These were questions that an international team of researchers sought to answer.

In 2019, a pair of bottlenose dolphins in the Caribbean—a mother and her calf—was filmed in the Chetumal-Corozal Bay in northern Belize using mud rings to catch fish.

This method of catching fish was first observed and documented in several parts of Florida by Stefanie Gazda, a researcher from University of Florida in 2005.

In this hunting strategy, one of the dolphins swims down to the seabed and uses their tail to stir up plumes of mud in a ring-shaped configuration. The loosened mud raises and forms a barrier that traps and corrals fish within.

Focusing on nine of the most commonly found dolphin, whale and porpoise species in UK waters, the strategy has been developed by the Scottish Government, in collaboration with the UK Government, the Welsh Government and the Northern Ireland Executive.

Its objective is to ensure the effective management to achieve and maintain the current favourable status of the nine species. It highlights certain pressures where further research or extra management measures may help to improve the conservation of marine mammals.

Equipped with an autonomous hydrophone, the buoy's function is to conduct for the first time real-time acoustic monitoring of the water's cetaceans to assess how oceanic noise pollution affects them. 

Deployed as part of the Smart Whale Sounds project, it will also track the distribution and behaviour of whale species in real-time and be used to train machine learning models to identify different species' calls. 

Before they were closed down, these fisheries would cause the deaths of many harbor porpoises, as they ended up as bycatch in the fisheries' gillnets. And based on the numbers, it is apparent that such coastal set gillnets had taken a greater toll on the harbor porpoises than we realized.

This is the finding of a paper published in the Marine Mammal Science journal.

This scenario may one day become reality. And to be efficient, such robots would need to be maneuverable and stealthy, and be able to closely mimic the movements of the marine creatures.

Scientists like Keith W. Moored are working on the next generation of underwater robots by studying the movements of dolphins and whales. "We're studying how these animals are designed and what's beneficial about that design in terms of their swimming performance, or the fluid mechanics of how they swim."

The Wildlife Trusts, which comprises 46 individual wildlife trusts around the country, reports record numbers of more than 800 sightings of whales, dolphins and seals in the waters of the United Kingdom in 2019.

Its Yorkshire project reported hundreds of individual sightings by trained citizen scientists. Among these were a pod of bottlenose dolphins making their way from Scotland to Flamborough Head in East Yorkshire-the farthest south they had been officially identified.