Atlantic surfclams support an important commercial fishery in the Northeast United States. Landings were valued at nearly $41.7 million in 2022. They also improve water quality by removing excess nutrients from the water when they filter and consume plankton. Our research aims to understand how surfclams respond to changes in their environment.
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NOAA Milford Lab scientists built a model that projects Atlantic surfclam growth based on water temperature and the partial pressure of carbon dioxide. This is a commonly used metric of ocean acidification. This model indicates that ocean acidification will decrease surfclam growth and reproduction by the year 2100, under the Intergovernmental Panel on Climate Change’s high carbon dioxide emission scenario.
Now we are studying surfclam populations in their natural habitat to see how well real-world observations match these model predictions. We will use data collected in the field to make our growth model for surfclams more accurate.
Research Chemist Matt Poach collecting surfclams from a clam dredge boat in Shinnecock Inlet, Long Island, New York. Behind, crewmembers of the F/V Susan H shovel clams from the dredge to a safe zone for the scientists to collect them. Credit: NOAA Fisheries/Katyanne Shoemaker
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Research Questions
- Does temperature or carbonate chemistry of either the seawater or the water within the sediment affect the growth of surfclams?
- Do differences between the subspecies affect the relationship between environmental conditions and growth?
- How well do our lab-based growth models predict surfclam growth rates in the field based on the environmental conditions of their habitat?
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Habitat Characterization/Environmental Monitoring
Surfclams spend most of their time burrowed in the seafloor. We sampled seafloor habitats and their associated surfclams monthly from 2021–2023 to find out whether their growth rates correlate with the sediment chemistry where they live. We collected seawater, water within the sediment, and surfclams at each of our five study sites.
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Current Surfclam Population Monitoring
We are collecting adult surfclams from each of our 3 field sites once per season to monitor differences in growth and condition of surfclams living in different environments. We use clam rakes to sample clams from our two Massachusetts sites. The clams live in deeper water at our Long Island, New York site, so we use a clam dredging boat to collect adult surfclams there.
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Transplant Experiments
Our transplant experiments will help define the role of the environment on growth compared with the role of genetic differences between populations and subspecies. From June 2022–2023, we conducted a transplant experiment to evaluate the growth of the northern subspecies in its native habitat compared with a habitat where only the southern subspecies lives.
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Larval Ocean Acidification Challenges
We plan to bring adult surfclams from Westport and Provincetown, Massachusetts, into the lab to spawn and produce larvae during summer 2025. We will expose the larvae to several different pH and food conditions based on field site measurements and predicted future carbon dioxide concentrations in the ocean. In addition to survival and growth, we will measure the respiration rates of the larvae and differences in gene expression between treatments.
NOAA Northeast Fisheries Science Center, 10 March 2025. Full article.
