Ma. Preece et Pv. Mladenov, Growth and mortality of the New Zealand abalone Haliotis iris Martyn 1784 cultured in offshore structures and fed artificial diets, AQUAC RES, 30(11-12), 1999, pp. 865-877
Comparisons of growth and mortality were made over 12 months for the New Ze
aland abalone Haliotis iris Martyn 1784 (blackfoot paua), fed two artificia
l diets (Coast Biologicals and Makara) and cultured in three offshore grow-
out structures: barrel, cage (a novel structure designed specifically for t
his study) and tube. Abalone grew significantly faster in tubes and cages (
mean length increase 61 +/- 10.7 mu m and 54 +/- 5.3 mu m day(-1) respectiv
ely) than in barrels (mean length increase 39 +/- 3.31 mu m day(-1)). Abalo
ne grown in tubes and fed a diet of Makara grew significantly faster than a
balone grown in tubes and fed a diet produced by Coast Biologicals. Abalone
in cages fed a diet produced by Coast Biologicals grew significantly faste
r than abalone in cages fed Makara. The difference in growth produced by th
e two diets may be related to improved food availability in cages throughou
t the feeding period. Mortality was high in all structures (66% of the enti
re experimental population) and did not differ significantly among structur
e and diet treatments, Mortalities were thought to be caused by a combinati
on of shell infestations (by burrowing worms) and silty water conditions wi
thin the grow-out structures. The commercial food conversion ratio was used
to compare the performance of diets within structures. Mean values ranged
from 13.9 +/- 5.6 for paua grown in barrels and fed Makara to 2.9 +/- 0.000
3 for abalone grown in tubes and fed Makara. It is likely that the food con
version ratio reflects a structure's ability to retain unconsumed food.