Growth of market-size abalone (Haliotis midae) fed kelp (Ecklonia maxima) versus a low-protein commercial feed

Abstract

The growth of grow-out abalone fed on kelp, with c. 10 % dry weight protein content, was compared with that of those fed on 'Feed A' (a new low-protein commercial feed of c. 26 % protein), in a flow-through system on a South African west coast commercial abalone farm. While both feeds produced similar gains in mean shell length (45.220 μm day⁻¹ for kelp, 46.839 μm day⁻¹ for 'Feed A'), the latter group significantly outperformed the kelp-fed group in terms of weight gain (0.266 % body weight day⁻¹ for 'Feed-A' abalone; 0.257 % body weight day⁻¹ for kelp-fed abalone). The 'Feed-A' feed may prove to be of considerable benefit as a substitute for the kelp plus high-protein feed that is sometimes used for abalone, because the former has most of the benefits of the two feeds, but none of their apparent disadvantages.