Entanglement of Olive Ridley Turtles Lepidochelys olivacea in ghost nets in the equatorial Indian Ocean
Records of olive ridley turtles, Lepidochelys olivacea, in the Maldives (n = 45) were compiled, as too were records of turtles entangled in nets from elsewhere in the topical Indian Ocean. With just two exceptions, all individuals for which measurements are available (n=37) were 61cm carapace length or less, i.e. immature. Most individuals were recorded in oceanic waters, which are believed to be an important habitat for juvenile olive ridley turtles. Most Maldivian records (84%) occurred during the northeast monsoon season and subsequent intermonsoon (December to April) when currents are predominantly from the east. This partly reflects the distribution of recording effort, but also suggests that many olive ridleys enter Maldivian waters from the east, possibly originating from the nesting beaches of eastern India. 71% of our recent records (n=34) were of olive ridley turtles entangled in pieces of fishing net (ghost nets), suggesting that this is an important cause of juvenile mortality. Since most forms of net fishing (including trawling, pelagic gillnetting and purse seining) are not used in the Maldives, the origins of these ghost nets must be international. During the northeast monsoon, when currents are from the east, the main sources of ghost nets appear to be Indian and Sri Lankan gillnet fisheries. During the southwest monsoon, when currents are from the west, an important source of ghost netting arriving in the Maldives is the western Indian Ocean tuna purse seine fishery, which uses very large numbers of net-festooned, drifting fish aggregating devices (FADs).