A new study from the University of Maine’s Aquaculture Research Institute and Darling Marine Center is helping to refine best practices for growing Atlantic sea scallops (Placopecten magellanicus), a species of increasing interest to Maine’s aquaculture sector.

Published in the academic journal Aquaculture, the research compares two scallop farming methods, ear-hanging and lantern net culture, over a complete grow-out cycle to determine which approach yields the best results for commercial growers, according to a news release from UMaine.

The study, led by UMaine postdoctoral researcher Christopher Noren, provides new insights into how each method influences scallop size and adductor muscle weight, a key factor in market value.

Evaluating Two Common Farming Methods

Maine’s scallop aquaculture industry is still in its early stages, and growers are looking for efficient ways to scale up production. Suspended culture is the most common approach, with farmers typically using multi-tiered lantern nets to grow scallops to a harvestable size. However, this method requires frequent maintenance to manage biofouling — an unwanted accumulation of microorganisms, plants and animals — and to optimize growth conditions.

Ear-hanging, a technique adapted from Japanese scallop farming, offers a potential alternative. This method involves drilling a small hole in the scallop’s shell and suspending it on a line, allowing for better water flow and potentially reducing maintenance needs.

To evaluate the effectiveness of each method, researchers partnered with two commercial scallop farms in Maine’s Penobscot Bay and Frenchman Bay. Over four years, they measured scallop growth and the weight of their adductor muscles, the primary product from scallops that are sold in U.S. seafood markets.

Findings to inform Maine’s aquaculture industry

The study found that scallops grown with ear-hanging culture had slightly larger shell heights, about 1–4% greater than those in lantern nets. More significantly, ear-hanging scallops had up to 12% more adductor muscle weight, which is the primary product sold in U.S. seafood markets and commands a higher price per pound when larger. This suggests a potential advantage for growers aiming to maximize profitability within that market. 

“We wanted to provide growers with data they could actually use on the water,” said Christopher Noren, doctoral researcher at UMaine and lead author of the study. “By comparing these two methods across a full grow-out cycle, we were able to identify where the biological advantages lie and how they might translate to better yields and more efficient operations.”

The results also highlight the role of temperature in scallop growth. Ear-hanging scallops grew more quickly in optimal conditions, which are between 50 and 59 degrees Farhenheit, but were more affected by colder winter temperatures than those in lantern nets.

“These findings give scallop farmers a clearer picture of how different methods impact growth and harvest timing. Understanding the trade-offs between techniques will help inform decisions about production strategies.” says co-author Damian Brady, a professor of oceanography at UMaine.

Supporting a sustainable, domestic seafood supply

The U.S. imports the majority of its seafood, including scallops, from foreign markets. As interest in domestic scallop aquaculture grows, studies like this can help Maine farmers refine their operations and improve profitability.  

“This research gives us real-world numbers to work with,” said Andrew Peters, owner of Vertical Bay LLC and co-author on the study. “Understanding how small changes in gear choice impact growth and market value helps us make smarter decisions as we scale up scallop farming in Maine.” 

By identifying methods that balance growth efficiency with labor demands, UMaine researchers are contributing to the development of a sustainable scallop aquaculture industry in the Gulf of Maine.

Founded in 1865 in Orono, UMaine is the state’s land, sea and space grant university with a regional campus at the University of Maine at Machias For more information about UMaine and UMaine Machias, visit umaine.edu/about/quick-facts/ and machias.edu/about-umm/umm-facts/.

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