The ability to manage a fish stock relies on the understanding of life history characteristics and basic biology of the species. Histological examination of gonads provides the most accurate determination of fecundity and spawning periods; however, this research is limited. Coastal pelagic fishes are often targeted commercially and recreationally due to their easy access by private vessels. Mesopelagic fishes have not been historically targeted, but are increasingly retained as incidental catch in pelagic longline fisheries. There is very little research into the biology of mesopelagic species, yet they are being heavily impacted. The objective of this study is to provide baseline data for four fish species important to Florida fisheries: the coastal pelagic fishes of blackfin tuna Thunnus atlanticus, skipjack tuna Katsuwanus pelamis, and little tunny Euthynnus alletteratus, as well as the mesopelagic escolar Lepidocybium flavobrunneum (often sold in sashimi restaurants as "white tuna"). Histological examination of archived gonad samples for these four species from 2007-2013 will provide data on spawning periodicity (single or multiple periods per year) and baseline fecundity of reproductive-age females. In addition to providing important baseline data for fisheries management, this project will develop the collaboration and local expertise at NSU for further histological examinations of fishes important to Florida commercial and recreational fisheries.