Reef fish around French Polynesia suffered destruction by 1997-98 El. nino caused by warmer seas.

High water temperature killed plankton, tiny marine creature on which reef fish survived but due to its lack, the number of reef fish has decreased.

Extreme temperature of El. nino, that is, change in temperature of Eastern Pacific, when raised to 3.5 degree C above average can be destructive to the world.

Dr Steve Simpson, university of Bristol said that Seychelles reefs also vanished due to the same reason.

Warmer water can cause danger for 500 million people who depend upon coral reef fish for their business or consumption.

Scientists found that by getting data for numbers of coral reef fish in French Polynesia, they can find out how fish exists in warmer water than average normal water.

Number of planktons existing in water can be studied by scientists by estimating the amount of chlorophyll as it is used by planktons for the process of photosynthesis.

Adult fish are also affected by warmer water just like baby fish. Current in water does not affect growth of reef fish that grow in water and return back to reefs where their adults laid eggs.

Simpson is finding effect of warmer water on other species which are also threatened.

Reef fish finds difficult to move with change in temperature; so it becomes very difficult to save its existence.