UNH Today

A UNH scientist is studying how to make nutrition for farmed fish less costly and more sustainable — work that stands to have important implications for the predominantly small-scale aquaculture operations in New Hampshire, for which profitability can be a struggle.

The work, which is being led by Karolina Kwasek, assistant professor in the department of biological sciences, and funded by the NH Agricultural Experiment Station, could lead to a welcome expansion of aquaculture in the state, which would both help sustain the appetites of regional seafood customers and support a thriving recreational fishing industry, as many hatcheries stock streams for sport purposes.

Current fish diets are expensive and hard to sustain

Fish begin life as tiny, transparent larvae with diet and environmental needs that differ dramatically from adults. Hatcheries use “live food,” plankton cultivated to provide a proven food source for growing larval fish, but it adds to the labor-intensive nature of larval care. Maintaining live food cultures is also unpredictable, and any problems can leave hatcheries with dead plankton and no food for their larval fish.

Kwasek is investigating how to meet the nutritional needs of larval fish, with the goal of developing a food source that is more efficient and dependable for hatcheries than live food, such as food pellets that can be stored until needed. She is also looking to broaden nutritional options once the larvae mature and begin transitioning to their adult diets. Exposing young fish to a new food source has been shown to have long-lasting effects, and adults previously exposed to it will eat it, while those not conditioned will not.

This approach can be combined with different feeding strategies to help the industry utilize more cost-effective ingredients and reduce reliance on natural resources. Alternating feeding strategies between plant-based and fishmeal-based feeds or the use of anti-inflammatory additives are other options to help build tolerance and reduce inflammation in fish caused by less expensive, more sustainable feeds such as soybean meal.

“A lot of my research can apply directly to New Hampshire fish farming,” says Kwasek. “I’m able to work with local producers and the New Hampshire Fish and Game department to learn more about the nutrition and feeding problems they’re facing. Our intent is to share our findings with the aquaculture community and help them overcome the problems in feasible ways. Our hope is that it will provide them with more options and help encourage diversification in local aquaculture.”

At home at UNH

UNH, with its active aquaculture program, proximity to marine and freshwater resources, nearby fish farmers, and extensive research facilities, has proven to be the right fit for Kwasek. It also provides opportunities for new collaborations.

In addition to her field work, Kwasek works with zebrafish, small, easy-to-care-for fish that are widely used in genetics and neuroscience research. Zebrafish serve as a good model for fish nutrition, and she has multiple research projects underway with them. Together with colleague Adam Brockett, assistant professor of biology, she is giving fish an option to exercise in an aquaculture setting to assess whether it helps boost their health and growth. Both are also working on a project to see how zebrafish brains are affected by different diets and different growth conditions. The findings can be used to guide fish feed makeup, improve animal welfare protocols in aquaculture, and provide insights into neural development and health across species.

“I’m lucky to be able to work with Adam and incorporate neuroscience in my work,” says Kwasek. “The collaborative opportunities I have at UNH are leading me down new paths.”