The ability of estuarine species to cope with environmental stress play a key role in the maintenance of their stocks. Commercial clams inhabiting Galician shellfish beds (NW Spain), areas usually co-occupied by the seagrass Zostera noltei, are often exposed to salinity drops because intense rains are becoming increasingly frequent. Since juvenile clams are more sensitive than adults, our main goal was to evaluate the effects of low salinity events on their survival and physiological condition as well as the physiological responses of Z. noltei and their interactions. Mesocosms simulated tidal cycles and three different salinity ramps (5-20, 10-25 and 35-35). Several indicators of performance for clams and Z. noltei were measured after three and six days of exposure and were repeated after four days of recovery. Results differed among species as Ruditapes philippinarum had not any significant response to low salinity stress while R. decussatus and Venerupis corrugata evidenced a decrease in oxygen consumption and clearance rate. However, after four days at ambient conditions, R. decussatus recovered normal physiological values but most of V. corrugata specimens died. Most of Z. noltei indicators were constant but the sucrose content dropped at the low salinity treatment. We found light interactions between clams and Z. noltei suggesting that seagrass could buffer salinity fluctuations in the short-term. The vulnerability of juvenile stages of clams to salinity drops should be a major concern to future management plans in the context of climate change.

Primary Presenter: Salvador Román, University of Vigo (salvador.roman.valle@uvigo.es)

Authors:

Salvador Román, University of Vigo  (salvador.roman.valle@uvigo.es)

Elsa Vázquez, University of Vigo  (eotero@uvigo.es)

Marta Román, University of Vigo  (marroman@uvigo.es)

Rosa M. Viejo, University Rey Juan Carlos  (rosa.viejo@urjc.es)

Celia Olabarria, University of Vigo  (colabarria@uvigo.es)