Genetic structure, phylogeography, and demography of Anadara tuberculosa (Bivalvia) from East Pacific as revealed by mtDNA: Implications to conservation.

Benoit Diringer,Gabriele Gentile,Krizia Pretell,Virna Cedeño,Cesar Chanta,Ricardo Avellan

doi:10.1002/ece3.4937

Abstract

Wild populations of the pustulose ark, Anadara tuberculosa (Bivalvia), an emblematic species of the East Pacific mangrove ecosystem declined in South American countries (Colombia, Ecuador, and Peru) mainly due to overharvesting and habitat loss or degradation. Understanding the genetic aspects of geographic variations and population structure of A. tuberculosa, currently unknown, appears as a priority to fishery authorities in order to elaborate integrated and collaborative conservation policies for fishery management, aquaculture, and stock enhancement programs. We used mtDNA sequence data to investigate haplotype diversity, genetic structure, and demography of A. tuberculosa. Results indicate genetic homogeneity of populations distributed north and south of the equator, respectively. However, statistically significant differentiation emerged between northern and southern populations with pairwise ф ST values ranging between 0.036 and 0.092. The oceanic current system acting in the area (Panama Current and Humboldt Current) might play a role in limiting the larval dispersal of the species, still poorly understood. Demography reconstruction supported recent population expansion, possibly started after last glacial maximum. Our results would suggest separate and independent management of populations north and south of the equator.

Highlights

The pustulose ark Anadara tuberculosa (Mollusca, Bivalvia) is dis‐ tributed from the Gulf of California in Mexico to the region of Tumbes in northern Peru (Baqueiro, Massó, & Guajardo, 1982). Natural banks of this species develop in muddy sediments, in particular around the roots of the red mangrove, Rhizophora man‐ gle (Camacho, 1999)
To recover depleted aquatic animal stocks, strategies generally rely on quota implementation with, on one hand, permanent collec‐ tion restrictions based on animal minimum size limits and, on the other hand, occasional collection prohibitions during reproductive seasons
Strategy for restocking and enhancing stocks of natural aquatic populations has been focused on the mass release of hatch‐ ery‐produced animals (Arnold, 2008; Bell, Rothlisberg, & Munro, 2005). Such a strategy is attractive for aquatic species, in particular mollusks, considering their extremely high fecundity and the sub‐ sequent possibility to produce in hatchery millions of spat from a numerically limited wild broodstock

Summary

| INTRODUCTION

The pustulose ark Anadara tuberculosa (Mollusca, Bivalvia) is dis‐ tributed from the Gulf of California in Mexico to the region of Tumbes in northern Peru (Baqueiro, Massó, & Guajardo, 1982). To recover depleted aquatic animal stocks, strategies generally rely on quota implementation with, on one hand, permanent collec‐ tion restrictions based on animal minimum size limits and, on the other hand, occasional collection prohibitions during reproductive seasons. Such regulations are more or less respected and are com‐ plicated by their economic consequences for fishermen. Strategy for restocking and enhancing stocks of natural aquatic populations has been focused on the mass release of hatch‐ ery‐produced animals (Arnold, 2008; Bell, Rothlisberg, & Munro, 2005) Such a strategy is attractive for aquatic species, in particular mollusks, considering their extremely high fecundity and the sub‐ sequent possibility to produce in hatchery millions of spat from a numerically limited wild broodstock. Samples were collected from two sampling sites north of the equator (Colombia and Ecuador) and three south of the equator (Ecuador and Peru)

| MATERIALS AND METHODS

| DISCUSSION

| CONCLUSIONS

Findings

CONFLICT OF INTEREST