Intermediate Culture of Juvenile Sea Urchin Loxechinus albus by Feeding Ulva sp. and Macrocystis pyrifera in Chiloé Island, Chile

Abstract

An intermediate culture experiment involving juveniles of the sea urchin Loxechinus albus was carried out using a plastic net cage (80 cm square x 40 cm high) from January to June 1989 in Hueihue, Chiloé Island, Chile, in order to investigate their growth, when feeding on Ulva sp. and Macrocystis pyrifera as common algae in this region. Five experiments were conducted using juveniles found on suspended oyster culture lines in Linao. Experiments 1, 2, and 3 had a density of 1580, 3160, and 5220 individuals/cage, respectively, and mixed algae of U. sp. and M. pyrifera were fed. Experiments 4 and 5 involved feeding only U. sp. or only M. pyrifera, respectively, both including 1820 individuals/cage. After 149-day culture, juveniles of 4.5-5.7 mm in initial test diameter grew to 10.7-14.8 mm, and the survival rate in all experiments was more than 70%. The best growth was 14.8 mm (mean test diameter) of experiment 4, and the highest survival rate was 91% of experiment 1. The abundance of U. sp. and M. pyrifera was advantageous for the intermediate culture of L. albus in eastern coastal waters of Chiloé Island.