Age, Growth and Maturity of the Bonnethead Sphyrna tiburo in the U.S. Gulf of Mexico

• Published in: Environmental biology of fishes 2023-07, Vol.106 (7), p.1597-1617
• Main Authors: Frazier, Bryan S., Vinyard, Elizabeth A., Fields, Andrew T., Driggers, William B., Grubbs, R. Dean, Adams, Douglas H., Drymon, J. Marcus, Gardiner, Jayne M., Hendon, Jill M., Hoffmayer, Eric, Hueter, Robert E., Wells, R. J. David, Wiley, Tonya R., Portnoy, David S.
• Format: Article
• Language: English
• Subjects: Age; Animal Systematics/Taxonomy/Biogeography; Biomedical and Life Sciences; Brackishwater environment; Coastal waters; Environment; Estuaries; Females; Fork length; Freshwater & Marine Ecology; Genetics; Growth models; Life Sciences; Males; Maturity; Nature Conservation; Parameters; Population genetics; Population studies; Populations; Sphyrna tiburo; Vertebrae; Zoology
• ISSN: 0378-1909; 1573-5133
• DOI: 10.1007/s10641-023-01439-5

The age, growth, and maturity of bonnetheads, Sphyrna tiburo , inhabiting estuarine and coastal waters of the U.S. Gulf of Mexico (GOM) were investigated. Based on results of a concurrent population genetics study, two populations were examined, the eastern GOM and western GOM. Vertebrae were collected and aged from 1081 females and 811 males ranging in size 261–1060 mm and 227–898 mm fork length (FL), respectively. The von Bertalanffy growth model provided the best fit to length-at-age data. Eastern GOM von Bertalanffy parameters (length parameters in mm FL) were L ∞  = 844, k  = 0.23, t o  = -1.99, and L o  = 310 for females and L ∞  = 680, k  = 0.39, t o  = -1.44, and L o  = 294 for males. Western GOM von Bertalanffy parameters were L ∞  = 1005, k  = 0.20, t o  = -1.81, and L o  = 298 for females and L ∞  = 807, k  = 0.30, t o  = -1.44, and L o  = 285 for males. Maximum observed age was similar between populations with an overall maximum of 17.1 years for females, and 12.1 years for males. Length and age at 50% maturity for the eastern GOM was 661.5 mm and 4.9 years for females, and 564.1 mm and 3.5 years for males and for the western GOM 772.7 mm and 5.3 years for females, and 644.9 mm and 4.4 years for males. Bonnetheads in the eastern GOM generally grow faster and to smaller asymptotic lengths than those from the western GOM; however, longevity is similar between the two populations.