title: Age and growth of the gulf toadfish Opsanus beta based on otolith increment analysis.
abstract: In the present study, sagittal otoliths of confirmed male and female specimens of the gulf toadfish Opsanus beta that were collected monthly over the course of a year from Biscayne Bay, Florida, U.S.A. were analysed. The timing and frequency of O. beta spawning seasons are reported by examination of the gonado-somatic index. The estimated ages of males and females ranged from <1 year to 6 and 5 years, respectively. Strong sexual dimorphism in growth was apparent with von Bertalanffy parameter estimates for males of Linfinity=393.8 mm, K=0.30, t0=0.36 and females of Linfinity=201.1 mm, K=0.79, t0=0.47. Comparison with previously published growth trajectories of the more northerly distributed conspecific Opsanus tau showed that O. beta males had a higher growth rate. Female O. beta and O. tau growth trajectories appear similar, with an indication that the former becomes asymptotic at least a year before the latter. Results are discussed in the context of temperature regimes, reproductive energy allocation and waste urea excretion in the two species.
authors.affiliation: University of Miami, Rosenstiel School of Marine and Atmospheric Science, Cooperative Institute of Marine & Atmospheric Studies, 4600 Rickenbacker Causeway, Miami, FL 33149-1098, USA.
authors.forename: E
authors.initials: E
authors.lastname: Malca
authors.forename: J F
authors.initials: JF
authors.lastname: Barimo
authors.forename: J E
authors.initials: JE
authors.lastname: Serafy
authors.forename: P J
authors.initials: PJ
authors.lastname: Walsh
mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D024541:Batrachoidiformes / Q000254:growth & development* / Q000502:physiology; D049628:Body Size / Q000502:physiology; D005260:Female; D005431:Florida; D008297:Male; D010037:Otolithic Membrane / Q000033:anatomy & histology* / Q000254:growth & development; D012098:Reproduction / Q000502:physiology; D012737:Sex Factors; D013696:Temperature