Posts tagged ‘dolphins’

Dolphins Lead ‘Complicated’ Social Lives

bottlenose_dolphinIn what can only be described as “West Side Story” meets “Flipper,” scientists say they’ve discovered that male bottlenose dolphins break out into gangs to protect their females.

The researchers from the University of Massachusetts, Dartmouth, studied more than 120 adult dolphins, with a focus on the males, during a five-year period in Shark Bay, western Australia.

Their findings were published in the Royal Society journal Proceedings B.

Richard Connor, a co-author and biology professor who has studied these particular dolphins for more than 20 years, said male dolphins’ social lives were intense.

“It seems there is constant drama. I have often thought, as I watched their complicated alliance relationships, that their social lives would be mentally and physically exhausting,” he told Discovery News. “I’m glad I’m not a dolphin.”

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US agency stops seismic energy tests in Gulf out of concern for ailing dolphins during calving

NEW ORLEANS — With sick and dead dolphins turning up along Louisiana’s coast, federal regulators are curbing an oil and natural gas exploration company from doing seismic tests known to disturb marine mammals.

The U.S. Bureau of Ocean Energy Management has told Global Geophysical Services Inc. to not conduct deep-penetration seismic surveys off the Louisiana coast until May when the bottlenose dolphin calving season ends. The agency says the surveys are done with air-guns that can disrupt mother and calf bonding.

The company says it laid off about 30 workers because of the restriction, which it called unnecessary.

Environmental groups are suing BOEM over the use of underwater seismic equipment and say the restrictions should be extended to surveyors across the Gulf of Mexico.

Written by The Associated Press

Male dolphins are bisexual, say boffins

MALE dolphins’ complex social lives include spending time in bisexual and gay relationships, scientists have found.

Researchers studying 120 bottlenose dolphins found the males made a series of alliances with the same sex.They also formed gangs between four and 14-strong in Shark Bay, Western Australia.dolfijnen

Richard Connor, of the University of Massachusetts, US, said: “I work on the male dolphins and their social lives are very intense. It seems there is constant drama.”

Females, in contrast, do not form any strong friendships.

There was only one observation of females forming a temporary coalition against young males, the journal Proceedings of the Royal Society B reports.

Most animals form alliances to defend their territory. But the study did not find any evidence of this. Instead the male dolphins appeared to live in a society without boundaries. The mammals paired and teamed up for a time, before splitting apart and switching between male and female partners.

Written by The SUN

Keeping Scotland’s whales, dolphins and sharks safe

bottlenose-dolphin-scotlandFebruary 2012: A new report on whales, dolphins and basking sharks in the Pentland Firth and Orkney Waters should help inform marine energy development in the area.

The report was commissioned by Scottish Natural Heritage (SNH), through funding from Marine Scotland. It forms part of wider efforts to find out more about the possible interactions between marine devices and protected species.

Orkney and the Pentland Firth is one of the richest areas in the UK for whales and dolphins, with 19 species recorded in the past 30 years. Minke and killer whales regularly occur there along with Risso’s, white-beaked and bottlenose dolphins.

Harbour porpoises and long-finned pilot whales are recorded year-round with basking sharks and other whale and dolphin species making casual visits.

Balancing the needs of industry with nature
Some of the proposed development sites, including those in the Pentland Firth, directly overlap with important areas for whales and dolphins. The report will therefore help developers decide where best to locate their marine energy devices.

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Dolphins at Sea Greet Each Other

When groups of dolphins meet up in the open sea they thoughtfully introduce themselves.

Bottlenose dolphins swap signature whistles with each other when they meet in the open sea, a new study reports, suggesting that these marine mammals engage in something akin to a human conversation.

Earlier research found that signature whistles are unique for each dolphin, with the marine mammals essentially naming sciencethemselves and communicating other basic information.

A signature dolphin whistle in human speak, might be comparable to, “Hi, I’m George, a large, three-year-old dolphin in good health who means you no harm.”

The latest study, published in the Proceedings of the Royal Society B, is the first to show how free-ranging dolphins in the wild use these whistles at sea. The findings add to the growing body of evidence that dolphins possess one of the most sophisticated communication systems in the animal kingdom, perhaps even surpassing that of humans.

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More Endangered New Zealand Dolphins Die In Nets

Last week, on the 22nd of February, two more New Zealand (Hector’s) dolphins died, entangled in a gill net washed ashore on a beach on the east coast of New Zealand’s South Island.

hectors_trappedThe two dolphins were found near the Waimakariri River mouth some 30 km inside the northern limit of the Banks Peninsula Marine Mammal Sanctuary. Under fisheries legislation, set netting is banned along most of the east coast of the South Island out to 4 nautical miles.

The populations of these dolphins, unique to New Zealand, are being rapidly depleted by being killed in nets. It has been estimated that in the early 1970s there were about 30,000 dolphins. This has now dwindled to about 7000, a huge decrease in such a short time span. These dolphins are listed as “Endangered”, with the population trend rated as “decreasing”, on the IUCN Red List.

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Hundreds of dead bottlenose dolphins on Peru’s beaches (video)

Hundreds of dead bottlenose dolphins have washed ashore on Peru’s northern coast over this month, leaving officials struggling for answers as to what killed the marine animals. At least 264 dead dolphins were found over a 70-mile stretch of sandy beach, Agence France-Presse reported, citing Edward Barriga, an official with Peru’s Oceanic Institute (IMARPE). “We have taken samples to determine the cause of death,” Barriga reportedly said from Lambayeque.xlarge

Vast quantities of dead anchovies had also been found in the region, located nearly 500 miles north of Lima, the Peruvian capital. The head of a group representing Lambayeque aquafarmers, Jorge Cabrejos, said the anchovies appear to have eaten contaminated plankton, which then sickened the dolphins that ate the small fish. However, the authorities have not yet ruled out the possibility of hunting killings, the BBC reported. Local residents quickly carved up some of the mammals for meat, ITN reported.

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