Regulation of post‐larval development in the European eel: thyroid hormone level, progress of pigmentation and changes in behaviour

Abstract

Based on thyroid hormone concentrations and histological criteria, glass eels of Anguilla anguilla caught in the French Atlantic coast in January and November were found to be late metamorphic. The pigmentation of the glass eels was demonstrated to be regulated by thyroid hormones, and evidence is given that together, the end of the progression of pigmentation, a fully developed gut and a change in behaviour marked the end of metamorphosis.