Nutrient, fatty acid, amino acid and mineral analysis of natural prey of the Hawaiian monk seal, Monachus schauinslandi

Proximate nutrients, gross energy content, mineral, amino acid and fatty acid composition were determined for teleost, cephalopod and crustacean prey of the Hawaiian monk seal. Crude protein was highest in the octopus, Octopus cyanea (80.0%), crude fat was highest in the Muraenid teleost, Gymnothorax eurostus (14.1%), whereas crude ash was highest in the lobster, Panulirus marginatus (11.6%). Gross energies ranged from 4.0 +/- 0.01 kcal g-1 in the Labrid teleost Bodianus bilulunatus to 6.0 +/- 0.12 kcal g-1 in the moray eel, Gymnothorax undulatus. Essential amino acids occurred in lower concentrations as a percentage of the total amino acids (35.8 +/- 2.6%) than non-essential amino acids (64.2 +/- 2.6%), but the ratio of individual amino acids to total amino acid concentrations were similar to those required by some monogastric terrestrial species and fingerling salmon. The fatty acid concentrations varied widely among species (range = 1.2-16.5 mg 100 mg-1); however, the teleosts had higher total fatty acids than the non-teleosts. This study indicates that, from a nutritional standpoint, some prey may be more beneficial to the Hawaiian monk seal; however, these prey are not necessarily the most abundant or available to some populations of the monk seal.