Age, Growth, and Natural Mortality of Graysby, <i>Cephalophilis cruentata</i>, from the Southeastern United States

• Main Authors: Michael L. Burton, Jennifer C. Potts, Andrew D. Ostrowski, Kyle W. Shertzer
• Format: Article
• Language: English
• Published: MDPI AG 2019-06-01
• Series: Fishes
• Subjects: ageing; graysby; growth morphs; natural mortality
• Online Access: https://www.mdpi.com/2410-3888/4/3/36

Graysby (<i>Cephalophilis cruentata</i>) (<i>n</i> = 1308) collected from the southeastern United States Atlantic coast from 2001 to 2016 were aged using sectioned sagittal otoliths. Opaque zones formed February to June (peaking in April). Ages ranged from 2 to 21 years, and the largest fish measured 453 mm TL. Growth morph analysis revealed two regionally distinct growth trajectories: von Bertalanffy growth equations were <i>L_t</i> = 388 (1 &#8722; <i>e</i>^{&#8722;0.12(t+5.73)}) for fish from North Carolina through southeast Florida (northern region), and <i>L_t</i> = 267 (1 &#8722; <i>e</i>^{&#8722;0.17(t+6.20)}) for fish from the Florida Keys (southern region). When growth was re-estimated using a fixed <i>t₀</i> value of &#8722;0.75 to estimate for smaller fish, growth equations were <i>L_t</i> = 349 (1 &#8722; <i>e</i>^{&#8722;0.26(t+0.75)}) and <i>L_t</i> = 250 (1 &#8722; <i>e</i>^{&#8722;0.43(t+0.75)}) for fish from the northern and southern regions, respectively. The age-invariant estimate of natural mortality was <i>M</i> = 0.30 for all fish, while age-specific estimates ranged 0.88&#8722;0.28 y^&#8722;1 for fish aged 1&#8722;21 from the northern region and 0.89&#8722;0.47 y^&#8722;1 for fish aged 1&#8722;15 from the southern region. This study presents the first comprehensive analysis of life-history parameters for graysby from the Atlantic waters off the southeastern United States, including specimens from both recreational and commercial fisheries.