Growth and the energy budget of juveniles of the abalone Haliotis tuberculata (L.)

摘要

The spawning season of the most commercially important European abalone {Haliotistuberculata) was evaluated during the summers of 1996,1997 and 1999. The results ofthe present study show that the best time to start with semi-artificial spawning is frommid July using cultured abalone from the open sea in Guernsey, Channel Isles.Until 1996 Tetraselmis sueccica was the main source of food for juvenile H.tuberculata during their rearing stage (one to twelve weeks old) on glass plates.Nevertheless, this study showed that T. sueccica, as a sole food, is not sufficient forsuccessful development and growth of early juvenile abalone. However, marinediatoms such as Skeletonema costatum, Navicula ramosissima and Cylindrothecaclosterium were easily ingested and assimilated depending on the size of the animaland conditions of culture.This thesis studied the effect of different diets (mix of fresh seaweed, fishmeal and anabalone commercial) and temperatures (15, 18 and 22C) on growth and energybudget of juvenile abalone H. tuberculata over a 210 day period. Energy budget wasobtained by Ingestion (I), Egestion (E), Somatic growth (Pg), Reproductive investment(Pr), Excretion (U) and Pedal mucus production (M). All these parameters wereassessed for grouped and individual organisms. Animals fed on formulated diets(energetically rich) and cultured at 18 and 22C were shown to give better growthrates than the natural diet and preferentially allocated energy to gonad development.Thus, the combination of diet and temperature were factors that contributed to enhancegrowth rates and gonad development.The abalone commercial diet (CO) used in this study produced shell deformation in 89% of the population after four months of feeding juvenile abalone. The information ofthese studies have important implications when considering the nutritionalrequirements of cultured abalone when fed on formulated diets, which need to containnot only the energy, but also the necessary micronutients which are required toproduce good growth rates and also healthy animals.