Rosa Cueto Vega

During recent years, mass mortalities of cultured scallops became more frequent in Peruvian bays. One of the main drivers related to these mortalities was hypoxic events. This study was designed to understand the hypoxia phenomenon in these bays and to assess how the Peruvian scallop, Argopecten purpuratus, can cope with reduced oxygen levels in seawater based on individual size. First, we analyzed the relationships between dissolved oxygen saturation and other environmental parameters (the Coastal El Niño Index, temperature, salinity and pH) in bottom seawater, the frequency and intensity of hypoxic events in two main culture areas (Sechura and Paracas Bays), and their relationship with scallop mass mortalities. Then, we performed experiments with two size groups of A. purpuratus (31 and 80 mm shell height; seed and commercial size, respectively) to assess their respective survival time under severe hypoxia (1% oxygen saturation) at 16°C and a salinity of 35. Finally, the results of the field records and the experimental data are used to suggest ways to improve scallop cultivation along the Peruvian coast.

The mussel Mytilus galloprovincialis is one of the most important marine resources for aquaculture in Europe, and Galicia (NW Spain) is the EU's leading region for production. Variation in environmental and ecological factors exists in Northern and Southern estuaries of this region, and natural selection could have modulated genetic variation among populations with adaptation to local conditions as the driving force. Results from a previous genetic study using neutral markers suggested subtle genetic differentiation between mussel populations from both estuarine areas. In this new study, mussel samples from Northern and Southern estuaries were brought into a common environment to test for proteome differences due to genetic and permanent non‐genetic effects in populations from both estuarine areas, using both foot and mantle border tissues. Because the sex of the mussels was determined through histological tests, sex‐specific effects were also examined. Evidence of subtle differences in the foot proteome, dependent on mussel sex, were detected between populations from both estuaries. These differences were more marked for female samples. No evidence of proteome differences was found for the factors estuaries and sex in mantle border tissue. Candidate proteins with a potential role in local adaptation were identified and point to molecular functions that might be involved in responses to different stressors.