Growth and survival of adult long snout seahorse ( Hippocampus guttulatus) using frozen diets

Abstract

This investigation examined the effect of using three different natural frozen diets; shrimp ( Palaemonetes varians), mysids ( Mesopodopsis slabberi) and adult Artemia on the fitness condition of adult long snout seahorse ( Hippocampus guttulatus). At the end of the 12 week experimentation, significant differences on the final wet weight were found between the animals fed with the three different treatments ( F 3,54 = 33.31, P < 0.0001). Significant differences were found between the animals fed with adult Artemia and the ones fed with either mysids or shrimp ( P < 0.001), but no significant differences were found between the shrimp and mysid treatments ( P > 0.05). Seahorses fed with the shrimp and mysid treatments had an increase of 58.9% and 52.2%, respectively, between the initial and final wet weight, while for the animals fed adult Artemia there was a decrease in their final wet weight. Condition Factor (CF) and Weight Gain (WG) showed the same pattern of statistical significance. Significant differences were found between treatments (CF; F 3,54 = 11.49, P < 0.0004, WG; F 3,54 = 71.19, P < 0.0001), with the seahorses from the shrimp treatment having a higher CF and WG than those from the adult Artemia treatment ( P < 0.001), but not from the mysid treatment ( P > 0.05). The comparison of mean daily SGR and the FCR revealed similar results, as significant differences were found between treatments (SGR; H = 23.33 P < 0.0001, FCR; H = 23.84, P < 0.0001). Seahorses fed shrimp had higher SGR and better FCR than the ones fed adult Artemia ( P < 0.001), but weren’t different from the ones fed mysids ( P > 0.05). In this study, the Atlantic ditch shrimp ( P. varians) was successfully used as a frozen diet for H. guttulatus. Although no significant differences have been found between the shrimp and mysid treatments, the WG, CF, SGR and FCR were higher for the animals fed with shrimp. Results thus suggest the adequate use of these two frozen diets to improve the fitness condition of adult H. guttulatus.