General Chat

Friendly Fire? From New Scientist No.2523 Oct 2005: A long running dispute between environmental campaigners and the US navy over the effects of its sonar systems on whales has spilled into the courts. At issue is the navy's primary submarine-detection system which fires powerful sound impulses in the frequency range 1 to 10 kilohertz, and listens for the echo. The environmentalists say that the sonar pulses injure marine mammals and have led to several whale strandings near sonar training sites. The National Resources Defence Council (NRDC), an environmental action organisation based in New York City, says that in peacetime the navy could take simple precautions to reduce the impact of the sonar on maritime mammals, such as avoiding known marine mammals' habitats, feeding grounds and feeding areas. 'Military sonar needlessly threatens the whole population of whales and other marine animals' says a senior attorney for the NRDC. On 19th October it filed a lawsuit to force the issue. The navy says (with tongue firmly in cheek?-Len) it has long supported marine mammal research,and claims it watches (with sonar?-Len) for marine mammals during exercises and avoids marine sanctuaries or critical habitats 'if operationally feasible'. Len

Dolphins are superb swimmers, but their aquatic ability isn't just down to their streamlined shapes and immense power. A dolphin's skin gradually flakes off, being shed entirely every two hours and it's this flaking that helps them slip smoothly through the water. Scientists at the Kyoto Institute of Technology found that the flakes of skin reduce the number of vortices that form around the dolphin. These would normally increase drag. Drag is also reduced by the skin's undulations. 'The results of the study could help us build better boats, ocean liners and submarines' says the Institute's spokesman. len

Fishermen's nets killing dolphins (Reported 14.3.06). More than 7,000 miles of nets fixed to the seabed are being used by fishermen in the South West, where hundreds of dolphins and porpoises are washing up dead according to Government figures. The extent of the gill nets and other entanglement nets was disclosed to MPs by Ben Bradshaw the fisheries minister. Gill nets are used to catch monkfish, turbot and rays and are left on the seabed for several days. Spanish, French and Irish fishermen also use them in the western approaches. The Whale and Dolphin Conservation Society said Britain was failing to implement a law which requires the nets to be fitted with an accoustic device designed to keep whales and dolphins away from them. A study in the 1990s found that about 2000 harbour porpoises and 200 dolphins being killed each year in the area known as the Celtic Sea. len

A porpoise was basking in the Manchester Ship Canal last night, after swimming more than 20 miles inland. Apparently attracted by plentiful fish supplies in the waterway, it is being monitored by marine experts. The British Divers Marine Life Rescue said it was quite unusual for such a creature to swim so far upstream. However, it seemed to be in good health. Len

Dolphins know each other's names. Dolphins may be closer to humans than previously realised, new resarch has shown. They communicate by whistling out their own names. The evidence suggests that dolphins share the human ability to recognise themselves and other members of the same species as individuals with separate identities. The research on wild bottlenose dolphins will lead to a reassessment of their intelligence and social complexity, raising moral questions on how they should be treated. The Sea Mammal Research Unit at St Andrews University has found bottlenose dolphins to be among the animal world's quickest learners of new sounds. Each animal develops an individually distinctive signature whistle in the first few months of its life , which appears to be used in individual recognition. Bottlenose dolphins are the only animals other than humans to have been shown to transmit identity information independent of the sound of the callers voice. The findings are supported by other authorities. The Wild Dolphin Project at Florida Atlantic University said it was already clear that 77 known cetacean (whale & dolphin) species had rudimentary languages. Dolphin brains are nearly as large and complex, relative to body size, as as those of humans and that implies them being able to communicate. Dolphins may, however, be just the first of many species where individuals are known to have their own names. Other researchers have already found evidence for highly developed lanquage skills in parrots, crows and primates. All species living in large groups have advanced communication skills although not the human vocal apparatus - but they evolve other means. Perhaps humans are not so intelligent as they think themselves to be? len

never trust a species that grins all the time..........obviously up to something..................

Only humans, chimps and dogs grin. Porpoises smile. len

Whales (and all cetaceans) get emotional. Brain cells linked with intelligence and considered unique to the great apes have now been found in whales. They were touted as the brain cells that set humans and the other great apes apart from all other mammals. Now the specialist cells thought to process our emotions and even enable us to love, spindle neurons, have been found in whales and therefore will be in all related species. Spindle neurons, cells named for their shape occur in the parts of the human brain linked with social organisation, empathy, speech, intuition about the feelings of others and rapid 'gut' reactions. What's more, they have existed in cetaceans for at least twice as long as in humans and early estimates suggest that they could have thre times as many as us, proportionally.(The Anatomical Record Part A, DOI; 10.1002/ar.a.20407) I have said before that scientists can be a bit obtuse at times in refusing to acknowledge what most rational people believe. Who wants to bet that, before long, similar finding will be pronounced about elephants? len

I saw lots of baby seals to day which would have made a tasty meal for any whale