Growth and mortality parameters of the Atlantic big-eye, Priacanthus arenatus (Teleostei: Priacanthidae), off southeastern Brazil

Abstract

The Atlantic big-eye, Priacanthus arenatus, is a carnivorous, stenohaline, nocturnal fi sh that live on rocky bottoms in depths up to 130 meters, off Southeast Brazil. Age and growth of this species were studied on identifi cation and measurement of growth bands and age rings in 140 specimens of both sexes, with total lengths ranging from 29.9 to 53.5 cm, in the period of June, 1999 to May, 2000. Periodicity in ring formation was confi rmed by the bimonthly variation of the scale’s marginal increment, pointing out to an age change on September-October. The scale (S) grows with a negative alometric proportion to the individual’s length after the equation S = 0.016.L0.919 (r = 0.890; P<0.01), with statistical signifi cance of the regression slope (t = 2.023; P<0.05). The positive interception value of the L/S ratio (a = 5.06) reduces subestimation of the backcalculated lengths (25.5 – 49.1 cm TL) and corrects the negative alometry. The growth equation in length (cm) is Lt = 66.5 [1 – e – 0.169 ( t + 2.9) ]. The total mortality coeffi cient is 0.340. The Atlantic big-eye has a low growth coeffi cient (K = 0.169) and an intermediate size (L = 66.5 cm), features that linked to intermediate values of growth performance ’ = 2.874, ration M/K = 2.01 and longevity of the catchable stock, tmax = 17.7 years lead to its classifi cation as a carnivorous species of the fourth trophic level.