Dietary value of seaweeds occurring on the Pacific coast of Tohoku for growth of the abalone Haliotis discus hannai.

Abstract

The dietary value of 57 species of marine algae (25 brown, 25 red, 7 green) and one species of sea grass occurring on the Pacific coast of northern Honshu was studied for the effect on the growth of abalone Haliotis discus hannai using the method of single species feeding in the laboratory. The relative food value of each algae was obtained from the relative growth on the mollusc fed on each seaweed to those on the standard alga Eisenia bicyclis. Further classification of the algae into four grades from superior to null based on molluscan weight gain was attempted. Twelve species of algae were shown to be of superior value (21% of all surveyed) including Order Lami-nariales, Desmarestia spp., Chondria and Enteromorpha. Nineteen species of algae were ranked as having no value (33% of all). The average feed conversion efficiencies of the algae with the above zero values were 5.4% (23 spp.), 5.6% (18 spp.) and 4.9% (4 spp.) for brown, red and green algae, respectively.