Development, growth and survival of the larvae of queen conch Strombus gigas under laboratory conditions

Abstract

The development, growth and survival of Strombus gigas (Linné, 1758) larvae were studied over a period of 30 days in laboratory culture. The fertilized egg masses used for the larval culture experiment were collected in Alacran's Reef from March to September. Experiments were conducted at 29±1 °C. Veligers were reared at 200 larvae l −1 in 4-l containers. Larvae were fed with the algae Tetraselmis suecica at 1000 cells ml −1. At hatching for the egg masses from March to May and September, the larvae showed two velar lobes and 1.5 shell whorls; the larvae hatching from June to August showed two velar lobes and two shell whorls. The larvae reached metamorphosis between 25 and 29 days. The results obtained in the development show that the larvae of March, May, April and September have slower development than the larvae of June, July and August. The shell length at hatching was 290–300 μm, with an average of 300±6.17 μm ( n=630 larvae). Larvae hatching at March were measured to be 290±3.94 μm, and the larvae for June measured 300±8.31 μm. Average larval growth for March was 22.33 μm day −1; for the larvae from July, average larval growth was 30.00 μm day −1.The shell length obtained at metamorphosis was between 867 and 902 μm, with an average of 883±1.23 μm. The survival at settlement varied from 20% to 38%, with an average of 30±5.18%. The highest survival was found in June and July with 38±6.30%, whilst the percentage of survival for larvae of March and September was significantly lower, with an average of 22±7.22% and 20±7.02%, respectively.