Wiki World: Indian Ocean

Showing posts with label Indian Ocean. Show all posts

Whales Sing a Different Song

It was believed that all whales spoke the same language like a bird species, for example, where all the birds have the same song. New observations show that whales sing different songs depending on where they live in the world.

Humpbacks on either side of the Indian Ocean do not sing the same song. Western Australian whales would not be able to "understand" whales in Madagascar. The two groups have been isolated from each other for a long time.

It would be expected that whales in the Northern Hemisphere and the Southern Hemisphere would differ, but the Indian Ocean whales are quite close to each other. The southern whales only have one similar song theme. A song is a series of themes.

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Biology

Eight Stages Toward Coral Reef Collapse

Coral reefs may look okay but on closer examination they may be dying. Overfishing, particularly in the Indian Ocean, causes eight steps that lead to reef collapse. Each step is a stage toward the end of a reef.

Keeping fish numbers up is important. When the level falls below 1000 kilograms of fish per hectare seaweed growth increases as well as urchin activity. This is a major indication of a problem. If fish density falls below 300 kilograms a crisis is reached.

Until now, coral cover has been used as a measure of coral health. This research shows that coral cover is the last threshold: the reef is heading toward ecosystem collapse.

It is during the first three stages that constructive change will save a reef. Fishing should be regulated. If a reef is in the final five stages, it is near impossible to save it. Only marine reserves have really healthy coral reefs because fishing is restricted. Unmonitored reefs fare the worst. A management system for each reef needs to be developed and put in place.

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Science

DNA Tests on Coconuts Show They Have Been Used by Man for a Long Time

The mystery of coconuts is solved. This useful fruit has been used for centuries. Besides being a healthy food it can be used as a carrying container, made into charcoal, its fibre used to make rope and it will save your life if appropriately adapted as a flotation device.

DNA tests have been done on coconuts worldwide. They have been spread around so much by people transporting them in their travels that they are quite homogeneous by type. There are only two main kinds: one from the Indian Ocean region and the other from the Pacific. Tall types predominate. The dwarf coconut accounts for only 5 per cent of all coconuts.

Both types of coconuts are used for different purposes. The niu vai is the usual kind with sweet juice inside. Copra is obtained from the niu kafa. One mystery still remains. While their are two distinct types, Madagascar has a variety that is a combination of the Pacific and Indian Ocean types.

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Science