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Background: Results indicate the fishery might be catching small California sardine in some fishing areas that could produce growth overfishing. Objectives: To estimate the percentage of organisms caught below the minimum size and determining the potential variables affecting the organisms size caught by the fishery. Methods: we did data exploratory analysis, correlation analysis and explored the size´s seasonal and interannual variability. We used ANCOVA and ANOVA to find out the main driver determining sardine´s size. The response variable was the standard length, the ANCOVA model included six covariates, six factors and the first level interactions. Results: the standard length ranged from 64 mm to 230 mm, the mean was 158.6 ± 19.8 mm. Results suggest 32.9% of the organisms caught are below the minimum size, 12.9% above the tolerance limit (20%). Regarding the seasonal variation, results suggest the lower standard length value occurred during June and July, while the highest occurred in March. The ANCOVA model included 60 significant predictors; it explained 82.2% of the observed variability. ANOVA results suggested that the predictor variable explaining the majority of the variability was the factor Month (31.5%); the second was the factor year (9.5%) and the third was Boat (7.2%). Conclusions: Compliance with regulations would require reducing operations during June and July in zones IV-G and VI-G; this would help to avoid growth overfishing. However, it could face fishermen opposition that already face a close season. Regulations compliance would require that CONAPESCA and fishermen reach a consensus. Our results contribute to provide information to avoid growth overfishing and yield overfishing. They support the efforts that managers and fishermen are making to assure the sustainable exploitation of this fishing resource.

Se presentan los resultados obtenidos de evaluar la selectividad de las redes de enmalle utilizadas en la pesca de curvina golfina (Cynoscion othonopterus) en el Alto Golfo de California (AGC). En abril de 2009 se realizó un trabajo de campo en donde se evaluaron 187 lances de pesca comercial con tres diferentes tamaños de luz de malla, registrándose un total de 15,970 tallas de ejemplares de curvina golfina, con base en un diseño de muestreo probabilístico polietápico. Primeramente, un análisis exploratorio de los datos reveló que existe un patrón espacial en el esfuerzo pesquero y en los resultados de la captura (tanto en tallas como en peso total), que permitió estratificar de acuerdo a la zona de pesca. Bajo este marco, se obtuvieron diversos modelos de selectividad de los diferentes tamaños de las redes y frecuencia de tallas, por sitio de pesca, utilizando Modelos Lineales Generalizados. En este análisis se supone que la distribución del número de peces de una clase de talla es asintótica a una distribución de probabilidad de Poisson. Se ajustaron tres diferentes funciones de probabilidad exponencial: la función normal; la log-normal y la Gamma, evaluando el mejor ajuste en cada caso, utilizando como criterio la razón de máxima verosimilitud. De acuerdo con el modelo seleccionado, los resultados muestran que solamente el uso de redes de enmalle con 14.6 cm de luz de malla mantiene la pesca incidental de individuos menores a 65 cm por debajo del 35% y es la única que cumple con la normatividad mexicana.