Fishermen adapt to environmental change in varied ways, UMaine study finds


A study published in Ecology and Society by University of Maine researchers Kara Pellowe and Heather Leslie found that regulations and financial resources that influence how people fish have as great an effect on how they deal with change as where and how they fish. 


The ecologists, based at the Darling Marine Center in Walpole, took a deep look at how fishermen adapt to environmental and economic change in Baja California Sur, Mexico.  


The study includes research that Pellowe conducted as part of her UMaine Ph.D. dissertation in Ecology and Environmental Science, which she completed in August.


Over the last six years, Pellowe has traveled from New England to Baja regularly, working closely with fishermen who harvest chocolate clams (Megapitaria squalida) near Loreto Bay National Park, on the gulf coast of the Baja peninsula. 


“Alternatives matter,” says Pellowe. “Having different ways to respond to environmental and economic change is vital for individuals and communities to be able to thrive in changing conditions.”


Pellowe and Leslie reveal the different ways the Loreto fishermen respond to changing environmental conditions and identify distinct adaptive strategies among the fishermen, depending on what gear they use and how much access they have to financial capital and other resources. 


Like the local softshell clam in Maine, the Mexican chocolate clam is a culturally and economically important species, providing food and income for many households, particularly at times or in places when other opportunities are scarce.  


The traditional method of harvest for the species is free diving, where fishermen hold their breath and dive to the sandy bottom in search of clams. 


However, this traditional method is no longer legal. The alternative, permitted method of hookah diving requires the use of an air compressor on the surface with a hose to support extended time underwater by divers, similar to how some in Maine fish for urchins and other bottom-dwelling species. 


The researchers report that “the hookah technique allows fishers to access greater depths and to remain on the ocean floor for up to 4 hours at a time. Compared to the 60–90-s breath holds of the most experienced free divers, hookah diving’s extended periods at depth allow for efficient and high-yield harvests.” 


Pellowe conducted interviews with 35 chocolate clam fishers in the Loreto area as part of this research. All fishers, regardless of how they fished, reported using multiple strategies to adapt to changing environmental and economic conditions, including the number of clams available to harvest. 


“Maintaining a diverse suite of adaptive strategies is essential for individuals to cope in the face of future disturbance and change,” the researchers conclude. 


Some fishermen expressed a concern that the hookah method was contributing to declines in the number of clams, because of the efficiency with which hookah divers are able to harvest. 


Leslie and Pellowe continue to conduct research in Mexico with the support of the US National Science Foundation. They also recently initiated a project in collaboration with the joint shellfish committee of the towns of Damariscotta and Newcastle, focused on local shellfish populations. 


For more information about this and related work, readers are invited to contact Leslie at the Darling Marine Center, via 


Founded in 1965, the Darling Marine Center’s mission is to connect people to the ocean. The center’s researchers, staff and students work alongside fishermen, aquaculture entrepreneurs, marine industry professionals and other members of the community in Maine and around the world. More information is available at


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