News Photo by Temi Fadayomi Biological Science Technician for the U.S. Fish and Wildlife Service, Sarah Mansfield, and Fish and Wildlife Service Volunteer, Andy Noeske. Examining some fish as a part of their research on Friday At the Brown Trout Festival.

ALPENA — Throughout the Michigan Brown Trout Festival, U.S. Fish and Wildlife Service researcher Sarah Mansfield was busy gathering vital data on the fish populations in Lake Huron. Mansfield, a biological science technician with the Green Bay Fish and Wildlife Conservation Office, focuses her studies on understanding the dynamics of salmon and trout in the Great Lakes.

According to Mansfield, her team has been surveying the entire Lake Huron coast, collecting data on various fish species.

“We check if the salmon and trout have fin clips to determine if they’re wild or hatchery fish,” she said. “We also assess their gender and reproductive maturity, and collect samples for genetic and isotopic analysis.”

Mansfield said a key part of the research involves determining the age of fish by examining their scales and otoliths, or inner ear bones.

“We’re conducting a study on the reproductive life history of lake trout,” Mansfield said. “We collect gonad samples and fin clips to identify the genetic strain of each fish, which helps us understand their survival rates and movement patterns.”

Mansfield also emphasized the importance of public cooperation in her research.

“By allowing our technicians to sample your catch, you are assisting with the management of your fishery,” she said.

The success of the program relies on anglers participating and letting researchers gather samples. This week, Brown Trout Festival participants helped with the program’s research as some anglers offered their catches as samples.

The Great Lakes Fish Tagging and Recovery Lab is crucial in this effort, providing a coordinated fish tagging and marking program known as “mass marking.” This involves tagging millions of salmon and trout at hatcheries each year.

“Fish with clipped adipose fins are identified as hatchery-origin, while unclipped fish are presumed wild,” Mansfield said.

Mansfield says her work at the festival allows her team to collect valuable biological data such as length, weight, and maturity from both wild and hatchery fish.

“We collect data on all sorts of factors to help manage the fishery,” Mansfield explained. “This data is crucial for understanding natural reproduction levels and the success of various stocking strategies.”

According to Mansfield, the research conducted by her and her team informs management decisions made by state departments of natural resources across the region as they share their data with cooperative agencies to aid in fisheries management.

“The cooperative effort involving fishery management agencies, boat captains, and anglers will result in better management of the valuable fishery resources of the Great Lakes,” Mansfield said.

Temi Fadayomi can be reached at 989-358-5693 or tfadayomi@thealpenanews.com.