Expanding Year-Round Fish Production Through Surrogate Broodstock

This project is developing surrogate broodstock technology to improve year-round aquaculture production and help preserve important fish strains. Researchers are testing whether smaller, fast-maturing fish such as Fathead Minnows and Rainbow Darters can serve as surrogates for species that take longer to mature and spawn seasonally, including Common Carp and Walleye. 

The work combines fish biology, cryopreservation, and aquaculture engineering to create systems that could provide reliable access to fish gametes throughout the year. Researchers are also developing methods to cryopreserve reproductive tissues and germ cells to help safeguard valuable fish strains against disease outbreaks, natural disasters, or loss of genetic diversity. 

The project has potential applications for aquaculture production, invasive species management, fisheries conservation, and selective breeding programs. Researchers say the technology could eventually help support Walleye aquaculture development in Minnesota while reducing reliance on wild stocks.

Researchers successfully matured and spawned Rainbow Darters in a laboratory setting and developed a captive breeding protocol that may support future surrogate broodstock research for Walleye and other fish species. The team also established methods for enriching and transplanting Common Carp germ cells and demonstrated survival and migration of transplanted cells in host fish. Additional work confirmed successful sterilization of surrogate embryos, an important step toward developing surrogate broodstock capable of producing donor-derived gametes year-round.

• John Bischof, principal investigator, University of Minnesota Twin Cities 
• Michael Smanski, co-investigator, BioMADE Institute and University of Minnesota 
• Nicholas Phelps, co-investigator, Minnesota Aquatic Invasive Species Research Center 
• Kanav Khosla, postdoctoral associate, University of Minnesota 
• Kieran Smith, graduate research assistant
• Colby Johnson, University of Minnesota
• Kenrick Sengmany, University of Minnesota

Minnesota Sea Grant supported this project because it addresses two priority areas: healthy coastal ecosystems and sustainable fisheries and aquaculture. The research explores new technologies that could support local aquaculture production, reduce pressure on wild fish populations, and improve tools for managing invasive aquatic species. 

The project also brings together researchers, engineers, aquaculture businesses, and fisheries experts to address challenges important to Minnesota and the Great Lakes region, including Walleye production, fish conservation, and aquatic invasive species management.

Support for this project is provided by Minnesota Sea Grant’s 2024-2026 Biennial Request for Proposal program. Every two years MNSG awards approximately $2 million in research grants through a rigorous, competitive, peer-reviewed process. Researchers based in Minnesota, who are not federal employees, are invited to apply.