Comparing the growth and survival of tautog (Tautoga onitis) fed a diet of green crab (Carcinus maenas) or commercial pellets in a recirculating aquaculture system

Abstract

Tautog, a coastal marine wrasse, is a highly sought food fish in southern New England and the Mid-Atlantic region of the United States due to its firm white fillet. Tautog has been identified as a candidate species for marine aquaculture in the region. Unfortunately, previous grow out studies have documented slow growth, which is detrimental for aquaculture. However, these studies contrast with data from wild populations which indicate rapid growth in the first few years of life. It is theorized that these differences in growth could be due to available diets. In the wild, tautog primarily prey on mollusks and crustacean prey, while laboratory studies rely on commercial fishmeal-based diets. This study compared the growth and survival of juvenile tautog fed with chopped green crabs, commercial fish pellets and a hybrid diet consisting of both green crabs and pellets. Wild juvenile tautog were collected from local waters and cultivated in a recirculating aquaculture system for 250 days. Tautog fed the commercial pellet diet had a growth rate of 0.31 ± 0.11 mm/day, consistent with previous grow out studies. The average growth rate of tautog fed the green crab diet was 0.52 ± 0.13 mm/day, with a peak growth rate of 0.66 ± 0.07 mm/day. The hybrid diet was intermediate to the other treatments at an average growth rate of 0.46 ± 0.1 mm/day. Statistically significant differences were observed across treatment groups (P < 0.05). Survival was high in the green crab and hybrid treatments (96.7% ± 1.2% and 96.0% ± 2.0%, respectively), and lower in the pellet treatment (85.3% ± 9.5 %). Data from this study indicate that the growth potential of tautog is higher than previously documented in aquaculture studies. This study highlights the need for additional research to develop feed formulations for non-piscivorous marine carnivores.