Zoological Studies

Vol. 48 No. 1, 2009

Development and Growth of Larvae of the Dog Conch, Strombus canarium (Mollusca: Gastropoda), in the Laboratory

Zaidi Che Cob1,*, Aziz Arshad2, Mazlan Abd. Ghaffar1, Japar Sidik Bujang2, and Wan Lotfi Wan Muda1

1Marine Ecosystem Research Centre (EKOMAR), Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
2Department of Biology, Faculty of Science, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia

Zaidi Che Cob, Aziz Arshad, Mazlan Abd. Ghaffar, Japar Sidik Bujang, and Wan Lotfi Wan Muda (2009) Strombus canarium egg masses used in this study were collected while still underneath spawning females, and embryonic and post-hatching larval development was observed in the laboratory.  Strombus canarium larvae were reared at 200 larvae/L in 2-L containers with 0.22 μm filtered seawater medium at a salinity of 30 ± 1 PSU, and fed a single algal species, Isochrysis galbana, at 1000 cells/ml.   Fecundity was estimated at 48,745 ± 877 to 93,643 ± 1685 (n = 10) eggs/egg mass.  The incubation time was between 110.4 and 134.4 h (mean 122.43 ± 3.07 h, n = 7) at 29 ± 1°C, with a high hatching rate (mean 93.34% ± 1.68% hatched, n = 3).  The larvae have 2 velar lobes and 1.5 shell whorls at the time of hatching, with an average shell length of 216.77 ± 5.72 μm (n = 10).  Based on prominent larval characters and visible morphological features, S. canarium larvae can be assigned to 4 different development stages, i.e. stages I, II, III, and IV, which are described in this paper.  The larvae reached metamorphic competence at 17-23 d posthatching, and only metamorphosed when settlement cues (sediments from its natural habitat and 15 mM KCl) were introduced.  They showed a short period of metamorphic competence, and no spontaneous metamorphosis was observed.  Morphological changes and larval behaviors at the onset and during metamorphosis are also described.

Key words: Veliger, Development, Metamorphosis, Malaysia.

*Correspondence: Tel: 603-89215238.  Fax: 603-89253357.   E-mail:zdcc@ukm.my