Age, growth, and mortality of wahoo, Acanthocybium solandri, from the Atlantic coast of Florida and the Bahamas

Abstract

Wahoo, Acanthocybium solandri, constitute an economically important fishery for many coastal nations, but assessment of this living marine resource is hampered by a lack of basic life history information. The present study demonstrates that wahoo in the western North Atlantic Ocean are short lived, grow rapidly in their first year, achieve a very large size, and have high mortality rates. The largest individuals were female and the sex ratio was significantly female-biased (298 females: 223 males: 54 unknown sex). An edge analysis showed that annuli formed primarily during winter–spring, which supported the use of sectioned otoliths for ageing wahoo. Wahoo lived a median of 1.3 years, a mean of 1.8 years, and a maximum of 9.3 years (n = 469). They had a high instantaneous mortality rate (Z = 0.98), and they grew rapidly and to a large size; von Bertalanffy growth parameters were: L∞ = 1701 mm fork length (FL), K = 0.381, to = –1.63. Females had a very similar maximum age relative to males (maximum age 9.3 v. age 9.1 years), and they had a slightly, but not significantly, lower mortality (Z = 0.91 v. 1.1) than males. Females grew slightly, although not significantly, larger than males (L∞ = 1797 v. 1555 mm FL, maximum observed = 1804 v. 1585 mm FL). Presumably the piscivorous nature of wahoo feeding, as noted by others, fuels these fast growth rates. Comparative data are very limited but it appears that the survival rate of wahoo in the western Atlantic Ocean is not different now than in the 1960s.