Chemical composition and growth indices in leptocephalus larvae

摘要: Leptocephali grow at extremely high rates (>1 mm d−1), but, unlike most fish larvae, leptocephali may remain in the plankton as larvae for several months before metamorphosing into juvenile form. During their planktonic phase, accumulate energy reserves form of glycosaminoglycans which are then expended along with lipid to fuel metamorphosis. Otolith growth were determined using scanning electron microscopy four species common Gulf Mexico, Paraconger caudilimbatus (Poey, 1867), Ariosoma balearicum (Delaroche, 1809), Gymnothorax saxicola (Jordan and Davis, 1891), Ophichthus gomesii (Castelnou, 1855). Proximate composition, RNA:DNA ratios protein examined respect mass, length age. The leptocephalus strategy was strongly reflected indices. Mass (Y) all increased increasing age (X) according equation Y = aX b , where a is species-specific constant 1.05 < 2.40. accumulation acellular mass evident ratios, observed shift size from rapid greater increase These results suggest that proportion actively metabolizing tissue declines replaced by metabolically inert depot: glycosaminoglycans. can thus large very rapidly minimal metabolic penalty, an unusual successful developmental strategy.