Variaciones en la historia de vida de Anadara tuberculosa (Mollusca: Bivalvia) en el ecosistema de manglar de la costa Sur de Ecuador

Luis Flores,Luis A Cubillos,Roberto Licandeo,Elba Mora

doi:10.15517/rbt.v62i2.8501

Abstract

Anadara tuberculosa is one of the most important bivalves along the Western Pacific coast because of its commercial value. Nevertheless, the variability in growth, long-life span, natural mortality and reproductive parameters of this mangrove cockle has not yet been described. The aim of this study was to analyze these life-history traits in three areas of the Southern coast of Ecuador. Empirical and length-based methods were used to estimate these biological parameters. Body size data were collected from the commercial fishery between 2004 and 2011 in landing ports near to the Archipelago of Jambeli [Puerto Bolivar (PB), Puerto Jeli (PJ) and Puerto Hualtaco (PH)]. The von Bertalanffy growth parameters for combined sex were estimated between 70.87 to 93.45mm for L(infinity) and 0.22 to 0.80/year for k. The growth indices (PHI') ranged from 3.17 to 3.85, while the overall growth performance (OGP) ranged from 5.03 to 5.82. The mean of long-life span (t(max)), size and age at maturity (L50% and t50%) were estimated in 7.71 +/- 2.53 years, 39.13 +/- 2.24mm and 1.46 +/- 0.56 years for PB; 9.51 +/- 2.85 years, 37.78 +/- 1.95mm and 1.37 +/- 0.41 years for PJ and 5.81 +/- 2.11 years, 39.73 +/- 3.31mm and 0.94 +/- 0.41 years for PH. Natural mortality (M) ranged from 0.46 to 1.28/year. We concluded that significant intra-specific variation was observed in a temporal scale in PHI' and OGP indices as well as L50% and M. Therefore, temporal changes in these life-history traits should be taken into account when assessing the status of the mangrove cockle fishery.

Highlights

In natural population, A. tuberculosa is generally more abundant than A. similis
Data sources: Size data [Shell length (SL), mm] for the mangrove cockle, A. tuberculosa, were collected monthly based on a fishery-dependent sampling in landing ports closed to the Archipelago of Jambeli [Puerto Bolivar (PB) 3o15’40’’ S - 79o59’48’’ W, Puerto Jeli (PJ) 3o27’00’’ S - 80o03’06’’ W and Puerto Hualtaco (PH) 3o25’05’’ S - 80o05’0’’ W], Ecuador
Growth: The von Bertalanffy growth function (VBGF) was fitted to length-frequency distribution for each year using the NSLCA routine of the FISAT II (Gayanilo, Sparre & Pauly, 2005) according to the approach followed by Flores (2011) and Flores and Mora (2011) with some modifications

Summary

Introduction

A. tuberculosa is generally more abundant than A. similis (C.B. Adams, 1852) (Silva & Bonilla, 2001), and in the mangrove cockle fishery of Ecuador, the catch composition of these two species is dominated by A. tuberculosa. Flores and Mora (2011) identified that the reproductive biology of A. tuberculosa has been the main topics of study [e.g. gonadal development stages, sex ratio] for this species. They emphasized the lack of information regarding reproductive parameters such as size at maturity (L50%). The goal of this study was to characterize the intra-specific variability of growth, life span, natural mortality and reproductive parameters of A. tuberculosa on the Southern coast of Ecuador

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Conclusion