Spawning of American eel, Anguilla rostrata , relative to thermal fronts in the Sargasso Sea

Collections of recently hatched American eel leptocehali including specimens less than 5.5 mm total length suggest the following hypotheses: 1) that thermal fronts separating the northern and southern surface water masses of the Sargasso Sea form the northern limit of American eel spawning, and 2) that some feature of the surface water mass in the southern Sargasso Sea serves as a cue for adult American eels to cease migrating and begin spawning activity.