Earthplatform.com

Dolphins

Earth Platform > Animals > Marine Life > Dolphins
Every seven years, half of all dolphins in captivity die from marine pollution, habitat degradation, harvesting, low frequency sonar, entrapment in fishing gear and other stress-related illnesses. Luckily, a number of countries have now stopped or reduced the capture of wild dolphins, and knowledge and conditions are vastly improving. However, there are still many countries where conditions for captive dolphins are well below standards.
 

Dolphins

A lot of dolphins die in fisheries. In the North Sea alone, an estimated 10,000 harbour porpoises are killed in fishing gear each year.  In recent years there have been gear modifications  that make it possible for the dolphins, to escape once a fishingnet is closed. Not every country has made these modifications mandatory yet, so dolphins are still killed in this fishery. The dolphins killed in fishery are mainly common dolphins, spotted dolphins and spinner dolphins. Occasionally other species, including bottlenose dolphins, are caught as well, but their numbers are lower.

dolphinsEspecially in coastal areas, marine mammals are often disturbed by human activities. Collisions with boats and jet skis have already resulted in severe traumas and even deaths of marine mammals, including dolphins. Also, boat traffic in areas where dolphins usually rest or forage can disrupt their normal behaviour. The seemingly harmless human behaviour, such as swimming in areas where dolphins naturally rest, can result in disturbance and changes in behaviour. In a bay in Hawaii for example, where spinner dolphins came to rest, the increase in swimmers, has resulted in the dolphins leaving the bay. They had to find another resting area.

Dolphins are very acoustically oriented animals. With their natural sonar, they rely heavily on sound for their orientation, navigation and communication with other dolphins. Since the last century, the increase in boat traffic around the globe has resulted in a considerable increase in noise in the world's oceans. This has a negative effect on dolphin and whale navigation and communication. 

 

More about:

Turtles are one of the world's oldest animals. Now they are driven into extinction by pollution and hunting.
Commercial and 'scientific' whaling, as well as water pollution, still drives whales into an ongoing struggle for survival.

Dolphins in the news

Dolphins and Whales News -- ScienceDaily

Cutting-edge cameras reveal the secret life of dolphins - Dolphins have been recorded in rarely-seen activities of mother-calf interaction, playing with kelp, and intimate social behaviors like flipper-rubbing through the use of largely non-invasive new cameras.
Whales use nested Russian-doll structure to protect nerve tissue during lunge dives - Fin whales use two neatly packed levels of nested folds to protect the nerves along the floor of their mouth during lunge feeding, according to new research.
Whale-ship collisions - Scientists and government officials met at the United Nations today to consider possible solutions to a global problem: how to protect whale species in their most important marine habitats that overlap with shipping lanes vital to the economies of many of the world's nations.
Are drones disturbing marine mammals? - Marine researchers have made sure that their research drones aren't disturbing their research subjects, shows a new report. And they're hoping that others will follow their example to help protect wildlife in the future.
Feeding wild dolphins can hurt them, new study says - Wild dolphins are more likely to be injured if humans feed them — even through unintentional means like discarding bait — reports a new study.