A re-evaluation of age, growth, and batch fecundity in the California Barracuda, Sphyraena argentea, from Southern California based on specimens taken from 2000 to 2002

摘要

The purpose of this study was to re-evaluate the age and growth of the California barracuda, Sphyraena argentea, previously studied only by the interpretation of scale annuli, and to provide contemporary estimates of batch fecundity. Current data were compared with the results of two previous studies: Walford (1932) and Pinkas (1966). Barracuda were collected from various mainland and island locations in the Southern California Bight from San Diego to Santa Barbara using gillnets and hook and line from April 2000 to October 2002. Subsamples of mature oocytes from preserved ovaries were counted by eye to determine batch fecundity, which was best correlated to fish mass (R-2 = 0.40, df = 21, P = 0.001). Batch fecundity, as a function of mass, did not differ significantly from previously reported values (ANCOVA, F = 0.535, df = 1, 31, P = 0.470). For the first time, barracuda were aged using sectioned sagittal otoliths and data were fit to the von Bertalanffy growth equation. Age classes 0 - XVIII were represented and the growth rate was fast during the first year for both sexes. Females were significantly longer than males at every age class (ANCOVA, F = 3.934, df = 1, 402, P = 0.048). A subset of fish was also aged using scale analysis to facilitate comparison to previous studies. Scales were deemed unreliable as aging structures for fish older than 4years, however, otolith-determined ages were not significantly different from scale ages for age classes 0 to IV (ANCOVA, F = 0.105, df = 1, 75, P = 0.746). The current study collected more young-of-the-year S. argentea than historical studies. Additionally, otolith analysis provided greater age class resolution for older fishes, which were previously assigned unreliable ages. Growth rates for age classes I through IV were significantly higher than those reported in both Walford (1932) (t = -10.36, df = 2, P pound 0.05) and Pinkas (1966) (t = -10.08, df = 2, P pound 0.05). We propose that the apparent change in growth rate could be related to the warm/cool regimes of the Pacific Decadal Oscillation.