SCUBA News 166,
31 March 2014
SCUBA News (ISSN 1476-8011)
Issue 166 - March 2014
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For Backpacking Travel Insurance with diving to 50 m, go to World Nomads, the adventure travel specialists
Iceland has dive sites that are unlike any others. She is most famous for her fresh water dive sites in the national park of Thingvellir. Here you dive in a narrow crack between the American and the European continental shelves in astonishingly clear water.
New list compiled from your votes. Wrecks take the top three spots: Blockship Tabarka in Scapa Flow, Cirkewwa in Malta and the Zenobia in Cyprus. Cast your vote or find out more at
More questions and answers on how to transfer from one diving agency to another.
The numbers of these beautiful, graceful animals are decreasing, and they are already on the IUCN Red List of endangered species. The IUCN writes that "Perhaps the most detrimental human threats to green turtles are the intentional harvests of eggs and adults from nesting beaches and juveniles and adults from foraging grounds.". Other threats include fishing bycatch, loss of habitat, light pollution, disease and unbalanced sex ratios caused by warmer temperatures in nesting areas.
The book Fire in the Turtle House tells how turtles have been hunted to populations that are a shadow of their former glory and how they now face widespread fibropapillomatosis (or FP), a debilitating plague of tumours that threatens to consign them to the history books.
A further problem is that over 37000 green turtles a year are legally killed each year, mostly by Nicaragua, Papua New Guinea and Australia.
The sex of turtle hatchlings is determined by the temperature at which the eggs develop in the nest. Higher temperatures favour the production of females. Turtles have evolved to synchronize their nesting with times of year when the incubation temperature produces roughly equal numbers of male and females. In areas where turtles are already nesting at the coolest time of the year, any increase in temperature means fewer and fewer males.
A female turtle breeds only every three to four years, although she lays several clutches of eggs in a nesting season. However male reproductive intervals may be shorter than the females', and males may visit multiple rookeries. Which could offset the male - female imbalance.
Some interesting methods are being tried to reduce green turtle bycatch. For instance, attaching ultraviolet light-emitting diodes to nets reduces bycatch of the turtles by 40%.
Green turtles appear to be the longest-lived of any sea turtle. Some estimates put it at up to 50 years. But estimates vary considerably.
They are also one of the largest turtles, growing to 120 cm and weighing 230 kg. Young turtles eat a variety of things but as they age they switch exclusively to seagrass and seaweed.
These Turtles can migrate more than 2600 km between their feeding and nesting grounds. Male turtles do not leave the sea except to bask in the sun. You find them in all tropical and sub-tropical seas.
Other Turtle Photos: More turtle photos are on our Google+ page
More at http://www.scubatravel.co.uk/marine-life/green-turtle.html
Underwater panoramas of dive sites in 19 countries - including Australia, the Galapagos and Bermuda - now on Google Map's StreetView. A great way to find out about dive sites before getting wet, and also a research tool for marine scientists.
Closing a hole-in-the-heart (PFO) using a catheter eliminates bubbles in the arteries and may reduce the risk of decompression sickness in divers, new study suggests.
Software has performed the first real-time translation of a dolphin whistle
The speed a ship is going means the difference between life and death for whales. New research has found that if ships are travelling at less than 10 knots then no right whales are killed.
During a night dive in Indonesia, scientist Mark Erdmann happened upon a new species of walking shark. The shark is one of nine walking species, six of which are found in Indonesian waters. It is about two to three feet long and uses its pectoral and pelvic fins to walk on the ocean floor, looking for food.
Over 42,000 turtles are legally killed each year, 80% of them endangered green turtles, a study suggests. Ten countries account for more than 90% of the catch, with Papua New Guinea, Nicaragua and Australia taking almost three-quarters between them. Legal take of turtles is comparable to estimates of by-catch.
Federal fishery managers have decided not to expand driftnet fishing into protected sea turtle habitat along the California coast because it would significantly raise the risk of capture and drowning of endangered whales, sea turtles and dolphins.
Hawaii recognises that it depends on the surrounding ocean for its sustenance - and a shark cull is not part of the picture. Western Australia should follow suit.
Scientists say it is unlikely that any fish can survive in the oceans deeper than about 8,200 metres. No fish has ever been seen living beyond this limit, but the researchers point to good physiological reasons why it should not be possible, also.
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