Reproductive Structures and Early Life History of the Gulf Toadfish, Opsanus beta, in the Tecolutla Estuary, Veracruz, Mexico

Although the Gulf toadfish, Opsanus beta, is an abundant member of the nearshore Gulf of Mexico ichthyofaunal assemblage, little information exists regarding the ecology of the species, especially for southern Gulf of Mexico populations. We added to the existing knowledge of this species by describing the reproductive structures and examining the early life history of this species in the Tecolutla estuary, Mexico. Macro- and microscopic examination of 7 males showed spermatogenesis to be similar to other teleost species except for the occurrence of biflagellate spermatozoa. Histological examination of the male accessory gland showed 3 tissue layers, but their functions are still undetermined. We found asynchronous development of oocytes in the ovaries of 16 females, which may indicate multiple spawning over the long spawning season noted in this study. Batch fecundity estimates among females ranged from 79 to 518 mature ova with a mean ovum diameter of 3.5 mm. The above-mentioned factors along with large size at hatching, attached larval forms, and paternal care may account, in part, for the abundance of this species in highly dynamic systems