W.L. Wiedemeyer-1998
Aquaculture Research, 29(1): 1-7
Abstract:
Spawning behaviour and embryology of the red-lipped conch, Strombus luhuanus L. 1758 (Strombidae, Gastropoda), was investigated from 4 April to 19 May 1991, at Okinawa, southern Japan. At the laboratory and at a water temperature of 22.5-23.5 C, veliger larvae developed 92 h after spawning. In all, 2140 larvae were examined for morphometric data. Growth and development was monitored at different water temperatures (23, 28 and 33 C), in natural sea water filtered through 150-micrometer, 60-micrometer and 1-micrometer screens and when fed various combinations of food organisms, namely Chaetoceros sp., Dunaliella sp. and Pavlova sp. The minimum duration of the pelagic period of the larvae was 14.5 days. Infestation by parasites was the main cause of high larval mortality before the age of 10-12 days if the water was not filtered at a minimum of 60 micrometers. Inappropriate food diversity was the most significant source of mortality beyond this age. The maximum age reached during all rearing experiments was 16 days. Under optimized feeding conditions and in natural sea water filtered at 1-60 micrometers, the pelagic period of S. luhuanus larvae lasted 16.5 to 17.4 days (95% confidence limits). Optimum water temperature was 23-28 C. A stepwise increment of filter sizes and a contemporary provision of a combination of specific supplementary food organisms is advised through grow-out of the larvae.
(Institut fur Meereskunde, Abteilung Fischereibiologie, Dusternbrooker Weg 20, D-24105 Kiel, Germany)