Giant trevally (Caranx ignobilis) of Hawaiian Islands can live 25 years

Abstract

Giant trevally (Caranx ignobilis) are an iconic reef fish of the Indo-Pacific, and yet knowledge of their life history is incomplete. The species is common in tropical and subtropical waters ranging from the far western Indian Ocean off South Africa to the central Pacific Ocean, where the species attains its greatest recorded size in Hawaii. Despite their broad range, importance as a top predator and attraction among anglers, the age and longevity of giant trevally remain largely undescribed and there are concerns that giant trevally are being fished down in the Hawaiian Islands. The most comprehensive age and growth study was performed in the Hawaiian Islands, but the work was limited to early growth observations. Although a study of daily increments was limited to fish less than maximum size, a model used to describe the growth characteristics was extrapolated to estimate that maximum age may exceed 20 years. In this study, otoliths of giant trevally from the Hawaiian Islands were investigated for annual growth zones, and the validity of the age estimates was tested and validated with bomb 14C dating. Revised growth parameters indicate giant trevally grow rapidly in the Hawaiian Islands and can attain an age of 25 years.