Settlement of Pinctada maxima (Jameson) and other bivalves on artificial collectors in the Timor Sea, Northern Australia

The type, abundance and growth of tropical bivalves that settled on artificial collectors in the Timor Sea off northern Australia was investigated. Collectors made of used monofilament net were set and retrieved over 5 periods between June 1993 and June 1994. A large number of bivalves were collected, encompassing 47 species from 14 families. Thirteen species from 6 families comprised over 90% of the total numbers, and included various species of commercial importance such as pearl oysters, fan shells and edible oysters. The silverlip pearl oyster, Pinctada maxima, was the most valuable of these and accounted for 2.4% total numbers. It had highest settlement rates during the wet season, between October to January, and a mean estimated growth rate of 5.8 mm/month. Settlement rates, examined for commonly collected species, tended to be highest during the wet season. Length-frequencies and growth rates of species with commercial potential are presented. Considering the number and type of species collected, there is potential for use of artificial collectors in tropical waters either for aquaculture or as a stock assessment tool.