Growth and mortality of the king angelfish, Holacanthus Passer (Actinopterygii: Perciformes: Pomacanthidae), in the central gulf of California, Mexico

Abstract

Background. The king angelfi sh, Holacanthus passer Valenciennes, 1846, is one of the principal species captured in the Gulf of California, Mexico, for the purpose of the aquarium trade. Although the species has been exploited for more than 40 years, studies have not yet been undertaken to understand the population parameters required for adequate management of the fi shery. The objective of this work was to describe for the fi rst time the growth and mortality of this species. The information provided in this study contributes to the generation of knowledge necessary to establish sustainable management practices. Materials and methods. The growth curve of the species was determined by applying a modal progression analysis of the sample length frequency distribution to determine the number of cohorts present through the multinomial statistic based on a probability function. Once the cohorts were identifi ed, the von Bertalanffy growth model was adjusted using a maximum likelihood function. To estimate the natural mortality rate and natural mortality-at-age, empirical methods were used. Were also estimated the size and age at fi rst maturity (Lm, tm), the maximum age (tmax), the fi shing mortality (F), the total mortality (Z), and the exploitation rate (E). Results. In total, 794 king angelfi sh were measured and weighed, including 659 juveniles and 135 adults. The total length of the fi sh ranged from 3 to 29 cm, and the weight was within 2-797 g. The potential weight-length relation was signifi cant (r2 = 0.94; P > 0.01), showing a negative allometric curve with the parameters: a = 0.108 and b = 2.618. The parameters of the von Bertalanffy growth equation were: L∞ = 37.894 cm, k = 0.127 year-1, t0 = - 0.658 years. The natural mortality rate was estimated to be 0.315 year-1. The following values were estimated for: Lm = 21.835 cm, tm = 6.10 years, tmax = 20.01 years, Z = 1.19 year-1, F = 0.88 year-1, and E = 0.74. Conclusion. Estimates of natural mortality could be linked to management measures such as catch quotas.