Abstract

In the western Atlantic Ocean wahoo, Acanthocybium solandri, occur from New Jersey to Columbia, including Bermuda, the Bahamas, the Caribbean Sea, and the GuIf of Mexico. Although wahoo support recreational and commercial fisheries throughout the western Central Atlantic, adequate life history data, including estimated size-at-age, for stock assessments are lacking. Sagittal otoliths from wahoo (935 - 1,803 mm FL) caught in the recreational fishery from the northern Golf of Mexico during May - September 1997 and 1998 and at Bimini, Bahamas in November 1997 and 1998 were examined to determine their potential use for age estimation. Whole sagittae and transverse thin-sections of sagittae viewed under transmitted and reflected light at 25 - 40x magnification generally revealed a series of ridges and faint opaque marks on the posterior portion of the distal surface of all whole sagittae and vague opaque marks on thin-sections from some sagittae. Attempts to enhance the visibility and contrast of the vague opaque marks (presumed growth zones) on thin-sectioned sagittae included application of histological stains (Toluidine Blue, Eosine Y, Neutral Red, and Analine Blue), etching with 5% EDT A followed by application of histological stains, etching and staining with mixtures of 1 % acetic acid and histological stains, and digestion with proteinase K buffer. Etehing and staining techniques did not delineate growth zones oor did they expose any "concealed" annual marks. Distinct opaque bands were obselVed only on sectioned sagittae from the two largest fish in the sample prior to the application of etching and staining agents, and a 2-h application of acidified Neutral Red provided the greatest visibility and contrast between presumed growth zones on those two sagittae.

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