Abstract
A spawning aggregation of Parexocoetus brachypterus was observed in the northeastern Gulf of Mexico over the outer continental shelf, 100 km south of Mobile, Alabama. The event was considered to be a spawning aggregation given the remarkably high abundance of flyingfish observed, together with unusually vigorous flying, jumping, and swimming activity near the surface, and observations of both males and females exuding ripe sex products when landed. The spawn occurred during May 2001 just after moonrise 2 days post full moon. More than 1 000 000 flyingfish were estimated to have participated in the spawn. Male flyingfish were three times more abundant than females, consistent with observations of 3–4 flyingfish grouped together before and after the spawning aggregation, if several males were simultaneously pursuing a single female. Although egg attachment to flotsam is the only reproductive mode previously described for flyingfishes with demersal eggs, the P. brachypterus spawn occurred in the absence of flotsam. Other possible egg development modes include egg suspension upon current, mid-water suspension above pycnocline or upon topographically induced turbulence, or benthic.