Studying Coastal Acidification Effect on the Atlantic Surfclam, Spisula solidissima through an Experimental and Modeling Survey

Emilien Pousse1, Matthew Poach1, Dylan H Redman1, George Sennefelder1, David Veilleux1, Melissa Krisak1, Mark S. Dixon1, Yaqin Li1, Eileen E Hofmann2, John Michael Klinck II3, Daphne Munroe4, Gary H. Wilkfors1 and Shannon Meseck1, (1)NOAA Fisheries - Milford, Milford, CT, United States, (2)Old Dominion University, Center for Coastal Physical Oceanography, Norfolk, VA, United States, (3)Old Dominion University, Center for Coastal Physical Oceanography, Norfolk, United States, (4)Rutgers University Haskin Shellfish Research Laboratory, Port Norris, NJ, United States
Surfclam fisheries rely on wild-caught populations that currently are sustainably managed and responsibly harvested. This species, however, is sensitive to physicochemical changes in its habitat, including temperature and salinity changes. Yet very little is known how this species may respond to ocean acidification, even though it has been identified as a highly susceptible to ocean acidification. A 3-month laboratory experiment, measuring physiological responses was carried out to investigate the effects of ocean acidification on juvenile surfclams. Surfclams (n=198 each treatment) were exposed to one of the three pCO2 levels (576, 1405, 2203 ppm) and were either fed or unfed. Every other week, growth, as well as physiological rates (feeding rate, respiration rate, ammonia excretion), were measured. Results revealed an appreciable decline in shell length and mass growth proportional to pCO2 concentrations. This decline can be attributed to reduced feeding rates (clearance rate, assimilation efficiency) and/or increased in metabolism activity (respiration, ammonia excretion).

The data was used to calibrate two individual-based models describing energetic fluxes within an individual and with this individual and the environment. Both models, Dynamic Energy Budget (DEB) and the surfclam model described by Hofmann will be adapted and compared on the basis of ability to reproduce surfclam growth exposed to different pCO2. The development of these models will enable projections on stock dynamics and economic impacts related to ocean acidification.