Gray Triggerfish Reproductive Biology, Age, and Growth off the Atlantic Coast of the Southeastern USA

Abstract

The Gray Triggerfish Balistes capriscus supports fisheries on both sides of the Atlantic Ocean. We utilized fishery-independent samples to assess the age structure, growth, sex ratio, size and age at maturity, spawning season, and spawning frequency of the Gray Triggerfish population off the southeastern U.S. Atlantic coast. From 1991 to 2012, 7,685 samples were collected, ranging in FL from 82 to 578 mm and ranging in age from 0 to 13 years. Our study provides key life history information for an exploited population and is the first to comprehensively describe age, growth, and reproduction for a Balistes species. We documented that the Gray Triggerfish is sexually dimorphic, with adult males attaining larger sizes at age and a larger maximum size than females. Sex-specific growth curves were fitted, yielding the following von Bertalanffy equations: FL t = 419[1 -e -0.54(t + 0.61) ] for males and FL t = 352[1 -e -0.94(t + 0.22) ] for females. This species is characterized by a medium size at maturity (the smallest mature female was 179 mm FL; the smallest mature male was 183 mm FL) and relatively early age at maturity (the youngest mature female and male were age 0). Some shifts in population attributes coincided with a period of increased fishing pressure. Due to tighter regulations on snapper and grouper fisheries, the Gray Triggerfish has become a more targeted species. Fisheries biologists and managers should continue to evaluate potential impacts and establish management regulations that consider the region-specific reproductive season, size and age at maturity, and sex-specific differences in growth documented in this study.

Queen Triggerfish Reproductive Biology in U.S. Caribbean Waters

“…Gonads were removed, weighed whole to the nearest 0.01 g, and then preserved for later histological processing to determine sex, sexual maturity, and reproductive phase using criteria modified from Kelly‐Stormer et al. (; Table ).…”

Factors affecting estimates of size at age and growth in grey triggerfish Balistes capriscus from the northern Gulf of Mexico

“…For example, Kelly‐Stormer et al . () reported an APE of 12% and Burton et al . () reported an APE of 11% for B. capriscus sampled in the Atlantic Ocean off the south‐eastern U.S.…”

“…data) found a ratio of 2·1:1 male to female for GOM fishery-dependent catches. Kelly-Stormer et al (2017) and J. L. Moore (unpubl. data) found that overall females were dominant in catches of B. capriscus from the southern U.S. Atlantic Ocean, but that males outnumbered females in larger size classes (>400 mm L F ).…”

“…That said, the greatest contributor to the relatively high APE reported here for B. capriscus spines, both for study samples (10·8%) and for samples with accepted age estimates in a reference set (9·1%), is the difficulty in interpreting and counting translucent zones in spine sections. For example, Kelly-Stormer et al (2017) reported an APE of 12% and Burton et al (2015) reported an APE of 11% for B. capriscus sampled in the Atlantic Ocean off the south-eastern U.S. In the end, it is assumed that ageing error was randomly distributed among samples and results of hypothesis testing were not affected by systematic bias in ageing.…”

“…Fractional age was determined by calculating fractional year using the equation: absolute value [(capture date − spawning date)365 −1 ]. The peak spawning date was set at July 1, based on B. capriscus spawning indicators (Ingram, 2001;Kelly-Stormer et al, 2017). Fractional year was added to calendar age if capture date was after July 1 or subtracted if capture date was before.…”