project news

Something fishy is going on round here...

News item submitted by Amelia Davies
News item dated 19 Nov 2010

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The team in Fiji have recently acquired an interesting piece of science equipment used to attract fish to the surface of the water, where they can be better observed. Technically known as a Fish Aggregation Device (FAD), these man made buoys or floats, tethered to the ocean floor with concrete blocks, seem to be irresistible to many species of fish. In effect, there are over 333 species belonging to 96 families which have been recorded to gather around floating objects.

The first observations of this aggregative behaviour dates back to ancient Greece, where a vase, estimated to have been painted in the VIII century B.C, depicts fish congregating under the floating corpse of shipwrecked seamen! However, pelagic fish are not just known to aggregate under corpses, they are regularly observed under a variety of floating structures such as floating algae, jellied zooplankton, logs, whales, rubbish, floats and FADs.

FADs first came onto the commercial scene between 1960 and 1970 in the Philippines, where they were used to attract Yellowfin Tuna for capture. The success of these first installations in aggregating fish have made these devices important in commercial, local and sport fisheries of many tropical and subtropical seas worldwide. More recently, FADs have been used for scientific purposes, as fish diversity observatories in pelagic ecosystems.

A variety of theories have been proposed in an attempt to explain this extraordinary behaviour. It has been suggested that fish aggregate under floating objects to feed on invertebrates associated with the structures, that the behaviour has evolved in order to safeguard the survival of eggs, larvae and juveniles during dispersion to other areas and that, in the case of Tuna species, floating objects are used as meeting places for school re-composition. However, the most widely accepted theory to date is that fish use floating objects, to some extent, as a source of protection from predators.

It is hoped that the FAD device recently installed at Frontiers Fiji marine project will provide opportunities not only to gain a better view of the fish species found on the western coast of Gau island, but to also act as a way of monitoring fish species diversity more closely and efficiently.


Read more about our Fiji Marine Project