ABSTRACT
The skipjack tuna (Katsuwonus pelamis) is a migratory pelagic fish occurring in all tropical and subtropical oceans of the world. Due to its economic importance and the unbridled increase in fishing efforts, stocks may collapse if this resource is not managed properly. The present study aimed to estimate growth parameters from different growth models based on annual rings from the dorsal spines of skipjack tuna caught in the western equatorial Atlantic. The first dorsal spine of each individual was extracted to produce cross-sections with 0.6 to 0.8 mm in thickness. We used a multi-model approach to select the best growth model based on the Akaike information criterion (AIC). Two hundred seventy individuals were analyzed, with an average length of 49.58 ± 7.72 cm. The von Bertalanffy growth model had the best fit to the data, but the Gompertz and Logistic models also had essential support. Average asymptotic length (LL) was estimated to be 114.05 and 102.63 cm for observed and back-calculated data, respectively. The dorsal spines are indeed efficient tools for estimating growth parameters and multi-model inference is a novel approach for adjusting discrepancies that likely result from a single-model approach.
O bonito-listrado (Katsuwonus pelamis) é um peixe pelágico migratório que ocorre em todos os oceanos tropicais e subtropicais do mundo. Devido à sua importância econômica e ao aumento desen-freado do esforço de pesca, os estoques podem entrar em colapso se este recurso não for manejado adequadamente. O presente estudo teve como objetivo estimar parâmetros de crescimento para di-ferentes modelos baseados nos anéis etários formados nos espinhos dorsais do bonito-listrado cap-turado no Atlântico Oeste Equatorial. O primeiro espinho dorsal de cada indivíduo foi extraído para produzir cortes transversais com 0,6 a 0,8 mm de espessura. Utilizamos uma abordagem de múltiplos modelos para selecionar o melhor modelo de crescimento com base no critério de informação de Akaike (AIC). Foram analisados 277 indivíduos, com comprimento médio de 49,58 ± 7,72 cm. O modelo de crescimento de von Bertalanffy teve o melhor ajuste aos dados, mas os modelos de Gompertz e Logístico também tiveram um suporte essencial. O comprimento assintótico médio (LL) foi estimado em 114,05 e 102,63 cm para dados observados e retrocalculados, respectivamente. Os espinhos dorsais são de fato ferramentas eficientes para estimativa dos parâmetros de crescimento e a inferência de multi-modelos é uma nova abordagem para ajustar as discrepâncias que provavelmente resultam de uma abordagem com base em um único modelo.
Subject(s)
Animals , Tuna/anatomy & histology , Tuna/growth & development , Atlantic Ocean , Brazil , Endangered SpeciesABSTRACT
Growth models of marine animals, for fisheries and/or aquaculture purposes, are based on the popular von Bertalanffy model. This tool is mostly used because its parameters are used to evaluate other fisheries models, such as yield per recruit; nevertheless, there are other alternatives (such as Gompertz, Logistic, Schnute) not yet used by fishery scientists, that may result useful depending on the studied species. The penshell Atrina maura, has been studied for fisheries or aquaculture supplies, but its individual growth has not yet been studied before. The aim of this study was to model the absolute growth of the penshell A. maura using length-age data. For this, five models were assessed to obtain growth parameters: von Bertalanffy, Gompertz, Logistic, Schnute case 1 and Schnute and Richards. The criterion used to select the best models was the Akaike information criterion, as well as the residual squared sum and R² adjusted. To get the average asymptotic length, the multi model inference approach was used. According to Akaike information criteria, the Gompertz model better described the absolute growth of A. maura. Following the multi model inference approach the average asymptotic shell length was 218.9mm (IC 212.3-225.5) of shell length. I concluded that the use of the multi model approach and the Akaike information criteria represented the most robust method for growth parameter estimation of A. maura and the von Bertalanffy growth model should not be selected a priori as the true model to obtain the absolute growth in bivalve mollusks like in the studied species in this paper.
El molusco bivalvo Atrina maura (Sowervy 1835) habita aguas marinas someras y estuarios en la costa del Pacífico desde Baja California, México hasta Perú. Es un organismo cuyo crecimiento individual ha sido insuficientemente modelado. El objetivo del estudio fue modelar su crecimiento individual absoluto mediante el uso de datos de longitud a la edad obtenidos de una región del Golfo de California. Los parámetros fueron obtenidos con el uso de cinco modelos de crecimiento; von Bertalanffy, Gompertz, Logístico, Caso 1 de Schnute y Schnute & Richards. Se seleccionó el mejor modelo usando el criterio de información de Akaike, AIC, pero se calcularon también la suma de residuos al cuadrado y la R² ajustada. Para obtener la longitud asintótica se siguió el enfoque de inferencia multi modelo IMM. Según el AIC el modelo que mejor describe el crecimiento absoluto de A. maura es el de Gompertz y colocó en cuarto lugar jerárquico el de von Bertalanffy. La longitud asintótica promedio encontrada, siguiendo la IMM, fue de 218.9mm (IC 212.3-225.5) de longitud de concha. Se concluye que tanto la IMM como el AIC representan las herramientas más sólidas para evaluar parámetros de crecimiento individual de A. maura y que el modelo de crecimiento de von Bertalanffy no debe ser seleccionado a priori como la opción para describir el crecimiento individual en moluscos bivalvos como la especie estudiada.