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Reproductive tactics of marine shellfish species from North-Eastern Venezuela: Ecophysiological implications

Abstract:

Within the context of the reproductive biology of species, strategies would include the total reproductive model shown by a species (strategies K or R), whereas the reproductive tactics would be variations in the physiological responses that individuals show in response to changes in local environmental conditions superimposed on the typical or basic model. This paper provides a general overview of the studies conducted to date on the reproductive tactics of 14 species of marine bivalves with economic importance distributed in the northeastern region of Venezuela and the importance of environmental variables. These species belong to the Families Arcidae (Anadara notabilis and Arca zebra), Pectinidae (Euvola ziczac and Nodipecten nodosus), Ostreidae (Crassostrea rhizophorae), Limidae (Lima scabra), Mytilidae (Perna perna, P. viridis and Modiolus squamosus), Pteriidae (Pinctada imbricata), Pinnidae (Atrina seminuda), Donacidae (D. denticulatus), Psammobiidae (Asaphis deflorata) and Veneridae (Tivela mactroides). All species showed reproductive asynchrony in at least one reproductive annual half cycle, except E. ziczac which showed reproductive synchrony in both. These species also showed a combination of opportunistic and conservative tactics in the first and second half of annual cycle. Only E. ziczac contrast with this pattern, showing only opportunist tactics that coinciding with the high availability of food between January and April (first pulse of coastal upwelling). In the second reproductive half cycle in June and July, E. ziczac undergoes renewed active gametogenesis coincident with a second pulse of coastal upwelling. The information included in this study could be used to formulate better policies to manage fisheries resources, including the periods of fisheries closures and production strategies.