Reproductive Cycle of Anadara tuberculosa (Sowerby, 1833)(Bivalvia: Arcidae) in a Mangrove System of the Chone River Estuary, Ecuador

Abstract:

The Population structure, sex ratio, sexual maturity index and the gametogenic cycle of Anadara tuberculosa were analyzed between November 2007 and October 2008, in the mangrove estuary of the Chone River. Random samples were collected from the artisanal fishery, for biometric and histologic analysis. Biometric parameters shell length (L), shell height (H), shell thickness (T), total weight (W) and Fulton metabolic index (K) presented significant differences between months and showed an isometric growth model. The metabolic index (K) decreased in inverse relationship with H. Monthly shell length frequency histograms show population bell shaped distribution, with maximum values between 40-50 mm L. Histological analysis showed that the sex ratio in different sizes is two females for each male, showing monthly differences between sizes and sexes. The presence of the females was independent of the sizes. with monthly differences (χ2, P> 0.05). The gametogenic and reproductive cycle was synchronized between sexes. The gonadic index did not differ between sexes, being a mature population with periodic spawning. Both sexes reproduce several times a year, with a low proportion of the population in atresia. Gamete production is continuous, and the reproductive strategy is opportunistic associated with food availability. Casual hermaphroditism was found. A low proportion of the sample analyzed showed individuals with female and male gonads dispersed in male acinus, this being the first report of casual hermaphroditism in

Año de publicación:

2020

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