Effects of a dry pelleted diet on growth and survival of the Yucatan octopus, Octopus maya

Abstract

The effect of a dry pelleted diet on growth of the Yucatan octopus (Octopus maya) was determined and compared with crab diet (Callinectes spp). Two groups of 15 wild collected animals were used. Octopuses were placed in isolation, in a flow-through system composed of 30 circular tanks ( 80 L), with a bottom of 40 cm in diameter and a water depth of 80 cm. Experiment lasted 40 days, and octopuses were weighed every 10 days to determine growth rates. Octopuses were fed between 7% and 10% body weight (BW) per day, twice a day at 9:00 h and 17:00 h. Uneaten food was removed after 4 h in the tanks and weighed, to determine food ingestion and conversion. No mortality as a result of natural causes was observed. The 15 octopuses fed on frozen crabs and the 15 fed on the artificial diet had similar weights (P > 0.05) at the start of the experiment, of 486.2 +/- 214.8 and 472.5 +/- 228.3 g, respectively. At the end of the experiment, octopuses fed on frozen crabs weighed 1466.5 +/- 484.0 g, and were significantly larger (P < 0.05), than octopuses fed on artificial diets (438.9 +/- 202.6 g). Growth rates for the experiment were of 3.3 +/- 0.2 and -0.0 +/- 0.3% BW per day, for octopuses fed frozen crabs and the artificial diet, respectively. The artificial diet did not promote growth, but animals did not loose weight and more important, ate regularly all the food supplied, with feeding rates higher than reported in the literature for prepared diets. This makes O. maya a good research animal for cephalopods.