The timing of metamorphosis and growth rates of American and European eel leptocephali:: A mechanism of larval segregative migration

Elvers of the American eel Anguilla rostrata (Le Sueur) and of the European eel Anguilla anguilla Linnaeus were collected, mostly during the 1995 fishing season, from six estuaries along the Atlantic coast of North America and from five European estuaries. The time of metamorphosis from leptocephalus to glass eel was determined from otolith daily growth increments in which the increment width and strontium:calcium ratios changed drastically. The overall mean age of European elvers was 350 days at metamorphosis ( T m) from leptocephalus to glass eel and 448 days at estuarine arrival ( T t), with 98 days between metamorphosis and estuarine arrival ( T t–m). These ages were all significantly greater than those of American elvers ( T m was 200 days; T t, 255 days and T t–m, 55 days) ( p