DNR researchers taking fish census to better manage Great Lakes

Large fishery vessels can be seen from some of the Great Lakes ports this year as research teams conduct annual fish population surveys through the fall.

Even before the surveys are completed, assessments of the state of fisheries in Michigan are coming in a up "pretty darn good," experts say. 

Michigan's Department of Natural Resources launched four large vessels based out of Alpena's Thunder Bay River, Charlevoix's Pine Lake, Lake St. Clair at the mouth of the Clinton River in Harrison Township and Marquette Harbor in the Upper Peninsula. 

"The staff on these vessels are working on a variety of studies to better understand Great Lakes fish communities, population sizes and habitats," said Gary Whelan, DNR Fisheries Research Program manager. "This information is critical for the DNR’s management of our aquatic resources and vital to understanding our fish populations."

The DNR's fisheries research stations and their vessels are evaluating specific habitats, sampling and determining why fish populations act as they do, and obtaining information for managers to determine future actions. Each vessel has a team of six to eight people including a captain, assistant boat captain, biologists and technician.

"DNR Fisheries Research vessels are absolutely critical for obtaining Great Lakes information and are the only ones who can safely obtain it using specialized Great Lakes sampling gear and expertise in big water fish sampling and surveillance," Whelan said.

Fishing plays a large role in the state’s economic ecosystem with commercial fisheries bringing in $20 million to $30 million each year. Whelan said the state relies on its huge sport fishing industry that's a $2 billion to $4 billion industry. 

"Great Lakes fishing contributes about half that, $2 billion, and is worth a lot of money," Whelan said. "It creates an excess of 30,000 jobs related to support fishing and is a major engine and driver for the state."

The research staff examines more than 150 species of fish in Michigan. The key species under examination this year are walleye, lake sturgeon, lake trout, Chinook salmon, Atlantic salmon, yellow perch, coho salmon, lake whitefish, lake herring, steelhead trout, smallmouth bass, round gobies, alewives and smelt. They are also evaluating the effectiveness of artificial reefs in multiple Great Lakes locations and are conducting a broad range of project-specific assessments.

Whelan said Michigan fisheries are as good as they have been in a long time.

"Lake Erie fishing is outstanding right now," Whelan said, "Saginaw Bay walleye populations are fully recovered, lake trout are doing well and improving in lakes Michigan and Huron, and we have a stable, self-sustaining and recovered lake trout population in Lake Superior.

"Lake Michigan’s salmon fishery has been very good with very large sized fish reported, although numbers are less than in the past. Lake sturgeon populations continue to move in a direction toward recovery. We’re in a good place from a fisheries perspective, and our smallmouth bass fisheries are some of the best in North America." 

Yellow perch is doing well on Lake Erie and Lake St. Clair but improvements are needed in Saginaw Bay, he said.

"One area we need to watch is our forage fish populations to ensure we can sustain our fisheries, Whelan said. "Inland fisheries have been really good, also. Overall, our fisheries are pretty darn good right now."

Teams will be sampling through October and are tackling potential threats like Asian carp that would disrupt the ecosystem.

“We do have grass carp established in Lake Erie, but other Asian carp like silver, black and bighead carp have not been established in the Great Lakes and hopefully, they will not," Whelan said. "We are doing everything in our power to make sure of that because we don’t know what their effects will be and undoubtingly, they won’t be good." 

Once a fish invades a system, they are difficult to manage and almost impossible to get rid of, he said. For example, sea lamprey invaded in the early 20th century and in spite of control efforts since the 950s at a cost of about $24 million annually, they have not been eliminated and continue to be an additional mortality factor for larger predator fish.

Whelan said another key threat the DNR is monitoring are the effects of climate change.

"There's no doubt our climate is changing, and we need to see how that will affect our fisheries," he said. "Our fisheries research section provides best estimates of the likely climate change effects and is developing potential management options for our inland and Great Lakes waters to effectively deal with climate change."

srahal@detroitnews.com

Twitter: @SarahRahal_