Age and growth of gray triggerfish (Balistes capriscus) from a north-central Gulf of Mexico artificial reef zone

The overexploitation of many traditionally targeted reef fishes, such as red snapper, Lutjanus campechanus (Poey, 1860), alongside the implementation of increasingly restrictive management measures on those species, has led to increased targeting of conventionally discarded Gulf of Mexico gray triggerfish, Balistes capriscus Gmelin, 1789, commercially and recreationally. The goal of this study was to assess age and growth of gray triggerfish from the Alabama Artificial Reef Zone in the north-central Gulf of Mexico. Gray triggerfish (n = 1135) were collected predominantly from artificial habitat during 1999–2017. Specimens were sexed macroscopically and ages were assigned by counting translucent increments in sections of the first dorsal spine. Fish ranged in size from 22 to 617 mm fork length. The oldest female was assigned an age of 9 yrs; the oldest male, 10 yrs. A suite of growth models was tested to develop combined and sex-specific models. The von Bertalanffy growth function best fit the combined data with parameters L_∞ = 488.63 (SE 5.19), k = 0.57 (SE 0.02), and t ₀= –0.27 (SE 0.03). Mean size-at-age differed between sexes for six of the eight ages which possessed sample sizes large enough to make comparisons. Growth differed between sexes, and the best-fitting version of the von Bertalanffy growth function permitted L_∞ to vary by sex [female L_∞ = 480.26 (SE 7.99); male L_∞ = 532.89 (SE 8.95); k = 0.44 (SE 0.04); t ₀ = –0.78 (SE 0.16)]. These findings enhance our knowledge of the age and growth of Gulf of Mexico gray triggerfish.