Latitudinal variation in the reproductive cycle of two bivalves with contrasting biogeographical origin along the Humboldt Current Upwelling Ecosystem

Roberto A Uribe,Silvia Aguilar,Carmen Yamashiro,José M Riascos,Marcelo E Oliva

doi:10.3989/scimar.03480.26d

Abstract

Argopecten purpuratus (Lamarck, 1819) and Mesodesma donacium (Lamarck, 1818) are bivalves that inhabit the Humboldt Current Upwelling Ecosystem. They have contrasting biogeographical origins, suggesting that their responses to exogenous factors should differ. Using circular statistics, we examine synchrony/asynchrony in the reproductive cycle between populations of each species. The results indicate that there is reproductive asynchrony in both species along their distributional range. However, there was synchrony for A. purpuratus in several location-pairs, including Paita-Chimbote, Chimbote-Callao, Callao-Pisco and Pisco-Antofagasta. For M. donacium , there were only two synchronic groups: Camana-Capellania-Mehuin and Hornitos-Penuelas-Longotoma-La Ligua-Cucao-Quilanlar. A. purpuratus showed gametogenenic activity throughout the year. In contrast, M. donacium showed strong seasonality, with gametogenesis in winter and spawning in spring/summer. In conclusion, the patterns observed for these sympatric species suggest that on a large scale the reproductive cycles follow the expected patterns for the contrasting biogeographic origin of each species, so it could be argued that they are modulated by endogenous factors. However, at a local scale, the reproductive cycles of these species show variation, likely determined by local oceanographic or hydrographic processes.

Highlights

The Humboldt Current Upwelling Ecosystem (HCUE) comprises several oceanic and coastal currents and influences a wide part of the west coast of South America, from southern Chile (45°S), up to northern Peru and Ecuador (4°S) (Strub et al 1998)
We examine synchrony/asynchrony in the reproductive cycle between populations of each species
The patterns observed for these sympatric species suggest that on a large scale the reproductive cycles follow the expected patterns for the contrasting biogeographic origin of each species, so it could be argued that they are modulated by endogenous factors

Summary

Introduction

The Humboldt Current Upwelling Ecosystem (HCUE) comprises several oceanic and coastal currents and influences a wide part of the west coast of South America, from southern Chile (45°S), up to northern Peru and Ecuador (4°S) (Strub et al 1998). The resulting Circumpolar Antarctic current impacts the southern coast of Chile, forming two currents: the eastward Cape Horn current and the northward Humboldt Current (Camus 2001). The latter, when mixing with the Equatorial Countercurrent, forms the HCUE. Upwelling is less active in northern-central Chile and more intense and continuous in centralnorthern Peru (Thiel et al 2007)

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