Rapid growth of wahoo (Acanthocybium solandri) in the Coral Sea, based on length-at-age estimates using annual and daily increments on sagittal otoliths

Abstract

Zischke, M. T., Griffiths, S. P., and Tibbetts, I. R. 2013. Rapid growth of wahoo (Acanthocybium solandri) in the Coral Sea, based on length-at-age estimates using annual and daily increments on sagittal otoliths. - ICES Journal of Marine Science, 70: 1128-1139.The wahoo (Acanthocybium solandri) is an economically important species incidentally caught in oceanic fisheries targeting tuna and coastal fisheries targeting mackerels. The age and growth of wahoo was examined using whole and sectioned otoliths from 395 fish (790-1770 mm LF) sampled from the Coral Sea. Growth increments were more reliably assigned on whole otoliths than sectioned otoliths. Edge analyses revealed that growth increments were deposited annually, primarily between October and February. Furthermore, analysis of presumed daily microincrements showed that ∼90% of fish had deposited the first "annual" growth increment by the 365th day, thereby indirectly validating annual increment formation. Wahoo were aged at between 108 d and 7 years, with 76% of fish being <2-year old. The specialized von Bertalanffy growth function provided the best fit to length-at-age data, with parameter estimates (sexes combined) of L ∞ = 1499 mm LF, K = 1.58 year-1, and t0 = -0.17 years. The growth performance index for wahoo in the Coral Sea (′ = 4.55) was one of the highest of all pelagic fish, with their growth and maximum size most similar to dolphinfish. This study suggests that wahoo are one of the fastest growing teleosts and provides growth parameter estimates that may facilitate future stock assessments and guide fisheries management. © 2013 International Council for the Exploration of the Sea.