Atlantic cod (Gadus morhua) are a historically important fishery in US waters. However, the sustainable management of this fishery has been a major challenge with the population currently struggling to recover from significant declines. Despite reduced quotas and a better understanding of population structures, cod aren’t reproducing as successfully as expected, particularly a stock that spawns in the spring. This suggests that overfishing may not be the only issue. Changes in what cod eat and environmental conditions could be affecting their ability to reproduce. Poor diet can lead to fish being in worse condition, which may cause them to skip spawning altogether.
To better understand whether food and environmental conditions are affecting cod recovery, Adrienne Kovach, a professor of Natural Resources and the Environment at the University of New Hampshire, and her team will study what spring- and winter-spawning cod eat throughout the year, and how their diets relate to their health and reproduction. The team will work with commercial and recreational fishers to collect samples, use genetic tools to identify different spawning groups, and analyze stomach contents using DNA techniques. By comparing diet, body condition, and reproductive health between spring- and winter-spawning cod, the team hopes to uncover why some groups are struggling more than others. The findings will help fisheries managers make more informed decisions, while also engaging fishing communities and the public through hands-on science and outreach efforts.
Principle Investigator
Adrienne Kovach, Ph.D.
Professor, Department of Natural Resources, University of New Hampshire
Adrienne.Kovach@unh.edu
Co-Investigators
Linas Kenter, Ph.D.
Aquaculture Research Scientist, NH Sea Grant and School of Marine Science and
Ocean Engineering, University of New Hampshire
Linas.Kenter@unh.edu
Nathan Furey, Ph.D.
Associate Professor, Department of Biological Sciences, University of New Hampshire
Nathan.Furey@unh.edu
Project Funding Cycle
2026-2027 NH Sea Grant Biennial Research Funding
Project Abstract
Sustainable management to support an economically viable Atlantic cod fishery is a major challenge in US waters. To help recover the fishery, recent management efforts have focused on spatial management and re-aligning cod management units with biological population structure. Yet, despite two decades of drastic cuts to cod quotas, recruitment has been inadequate and recovery not occurring for Gulf of Maine cod; productivity for the weaker, spring-spawning stock has been particularly low. This suggests there may be other explanations, besides exploitation, for low productivity and poor stockrecruitment relationships. Changes in prey fields and concerns about environmental impacts on body condition raise questions about the role of diet and nutritional condition on reproduction. Fish in poor condition – potentially due to poor diet quality – can suppress reproduction, and the resulting skipped spawning can have implications for stock-recruitment dynamics. In the western Gulf of Maine, energetic challenges may be different for the spring and winter-spawning stocks, due to different conditions they experience during gonadal development. This project seeks to address these concerns through a systematic study of seasonal diets for the winter and spring-spawning western Gulf of Maine cod stocks, in the context of body and reproductive condition. To address this goal, we will 1) partner with recreational and commercial fishers to collect cod stomach contents and genetic samples from Atlantic cod; 2) apply a genetic stock discrimination tool to determine the spawning stock of origin of sampled cod; 3) characterize the diets of cod using DNA metabarcoding; and 4) relate cod diets to body condition and reproductive condition for the two spawning stocks. Our findings will provide insight into the potential role of diet and condition in recruitment dynamics and differential productivity of western Gulf of Maine cod stocks – information that will be transferred directly to fishery scientist and managers in the Northeast Fishery Science Center and New England Fishery Management Council for informing management actions. Outreach efforts implemented in a community science framework will benefit
commercial and recreational fishers and extend the impacts of our work to broad public audiences, including recreational fishers, young fishers in the New England Young Fishermen’s Alliance, and the general public through presentations, blog posts and a podcast.
