Regional assemblages of leptocephali of 5 families of shelf eels (Chlopsidae, Congridae, Moringuidae, Muraenidae and Ophichthidae) from the Sargasso Sea and Florida Current were compared with hydrographic features and adult distributions. There were 2 major patterns in the distributions of the >37 species of leptocephali that were collected. First, more species and greater abundances were found at or south of fronts in the Subtropical Convergence Zone (STCZ) of the Sargasso Sea, with the most diverse assemblages at stations closest to fronts in the west. Second, the smallest leptocephali of all species were located close to the Bahama Banks, in the Florida Current and in stations close to southerly fronts in the western STCZ. The most distinct discontinuities in numbers of species occurred at fronts at the boundary between southern Sargasso Sea surface water and mixed convergence zone water. Impoverished assemblages were found north of these fronts and in the eastern STCZ. Species richness was highest in the Florida Current and at the westernmost frontal station in the STCZ. Anticyclonic circulation northeast of the northern Bahamas may facilitate entrainment of leptocephali from the Bahamas and Florida Current into fronts in the STCZ, which appear to transport leptocephali eastward. The circulation patterns of the region are hypothesized to influence both the regional assemblage structure and the diversity of life history strategies that may be used by eels inhabiting the region.
Leptocephali . Anguilliformes . Distribution . Species assemblages . Sargasso Sea . Florida Current . Fronts . Bahamas . Life history . Spawning . Larval transport
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