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Release density influences restocking success in the winged pearl oyster Pteria sterna

Olivera, Alex, Saucedo, Pedro E., Rangel-Dávalos, Carlos, Acosta-Salmón, Héctor
Ocean & coastal management 2019 v.167 pp. 100-103
Pteria sterna, adults, coastal zone management, juveniles, larvae, mortality, oysters, predation
A restocking experiment was conducted to determine the influence of release density on growth, survival with protection (natural), and survival without protection (by predation) in the winged pearl oyster Pteria sterna. Adult oysters were directly placed over the sea floor at 10 m depth in triplicate, 3 × 3 m parcels at densities of 5, 10 and 15 oysters m−2. Individual protection structures elaborated with dark, 31 mm plastic mesh were placed over each parcel. At the end of month 8, the structures were removed and the oysters were left unprotected thereafter to further assess mortality by predation. Oysters released at high density experienced a significantly greater increase in DVM and lower predation than oysters released at low density. Improved survival in oysters released at high density was likely influenced by the protection offered by the aggregation of individuals in dense clusters, compared to oysters stocked at low densities that did not form aggregations, or these were small. Oysters at all densities remained established at the restocking site and were likely to contribute at least once as breeders during the study to larval and juvenile recruitment back to the population.