Ciclo gametogénico de Acanthocardia tuberculata (Mollusca: Bivalvia) en la Bahía de M’diq (mar Mediterráneo)

The reproductive cycle of Acanthocardia tuberculata (Linnaeus, 1758) was studied in M’diq Bay. The gonadal development was determined by means of standard histological techniques, mean oocyte diameters and a condition index. Rough cockle is a gonochoric species with synchronous gonadal development and spawning in males and females. The sex ratio obtained was not significantly different to 1:1. Gametogenesis began in late winter (November) coinciding with the temperature drop. In June, with increasing sea water temperature, most of the population was spent and resting oocytes appeared dispersed in the gonad. Resting stage occurred from August to October, during which time sex could not be determined in 100% of the population. A. tuberculata showed a clear seasonality in its gametogenic cycle, with one spawning peak per year in June. Quantitative measurements of 6318 oocyte diameters indicated the patterns of development observed in the qualitative staging. The results obtained revealed the direct influence of temperature on the reproductive cycle. First sexual maturity occurred at 42.77 mm shell length. The information gathered in this study allowed preliminary management measures to be suggested for the fishery of this species, including a closed season during the main spawning season (May-June) and the establishment of a minimum landing size (at least 50 mm shell length) for A. tuberculata from the Moroccan Mediterranean coast.El ciclo reproductivo de Acanthocardia tuberculata (Linnaeus, 1758) se estudió en la bahía de M’diq. El desarrollo gonadal se determinó por medio de técnicas histológicas estándar, diámetros medios de ovocitos y un índice de condición. El corruco es una especie gonocórica con el desarrollo gonadal y desove sincrónico en machos y hembras. La proporción de sexos obtenida no fue significativamente diferente a1: 1. La gametogénesis comenzó a finales del invierno (noviembre) coincidiendo con la bajada de temperatura. En junio, con el aumento de la temperatura del agua de mar, la mayoría de la población era ovocitos gastados y dispersos en la gónada. La etapa de reposo entre agosto y octubre, tiempo durante el cual el sexo no se pudo determinar en el 100% de la población. A. tuberculata presentó una clara estacionalidad en su ciclo gametogénico, con un pico de desove en junio. Las mediciones de diámetros de 6.318 ovocitos dan los patrones de desarrollo observados desde el punto de vista cualitativo. Los resultados obtenidos revelaron la influencia directa de la temperatura en el ciclo reproductivo. La primera madurez sexual se produjo a los 42.77 mm de longitud de concha. La información obtenida en este estudio permitió sugerir medidas preliminares de gestión para la pesquería de esta especie, incluyendo una temporada de reposo durante el desove principal (mayo-junio) y el establecimiento de una talla mínima de recogida (de al menos 50 mm de longitud de concha) para A.tuberculata de la costa mediterránea marroquí

Gametogenic cycle of the rough cockle <em>Acanthocardia tuberculata</em> (Mollusca: Bivalvia) in the M’diq Bay (SW Mediterranean Sea)

The reproductive cycle of Acanthocardia tuberculata (Linnaeus, 1758) was studied in M’diq Bay. The gonadal development was determined by means of standard histological techniques, mean oocyte diameters and a condition index. Rough cockle is a gonochoric species with synchronous gonadal development and spawning in males and females. The sex ratio obtained was not significantly different to 1:1. Gametogenesis began in late winter (November) coinciding with the temperature drop. In June, with increasing sea water temperature, most of the population was spent and resting oocytes appeared dispersed in the gonad. Resting stage occurred from August to October, during which time sex could not be determined in 100% of the population. A. tuberculata showed a clear seasonality in its gametogenic cycle, with one spawning peak per year in June. Quantitative measurements of 6318 oocyte diameters indicated the patterns of development observed in the qualitative staging. The results obtained revealed the direct influence of temperature on the reproductive cycle. First sexual maturity occurred at 42.77 mm shell length. The information gathered in this study allowed preliminary management measures to be suggested for the fishery of this species, including a closed season during the main spawning season (May-June) and the establishment of a minimum landing size (at least 50 mm shell length) for A. tuberculata from the Moroccan Mediterranean coast