Showcasing the DNR: On patrol with the DNR's Great Lakes Enforcement Unit

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Conservation officer Mike Hammill inspects a Great Lakes catch.

On patrol with the DNR’s Great Lakes Enforcement Unit

Michigan Department of Natural Resources

A patrol boat used by the Great Lakes Enforcement Unit is shown.

The day begins hours before sunrise.

Gear, food and water are packed.

Preferably leaving the dock by 4 a.m., conservation officers in the Michigan Department of Natural Resources’ Great Lakes Enforcement Unit are ready to tackle the day, often logging 16-hour shifts, traveling up to 150 miles in the patrol vessel they refer to as their “office.”

Conservation officers with the unit enforce state rules and laws regulating state- and tribal-licensed commercial anglers. The officers are also responsible for monitoring commercial fish wholesale operations that occur on land.

Coming from the ranks within the DNR’s Law Enforcement Division, conservation officers in the unit acquire additional skills and training related to their job function.

“Our job is to protect the resource,” said Cpl. Marvin Gerlach, a conservation officer with the unit. “We want every child to have the same experience that their parents or grandparents were able to have – for young anglers to have the rush of excitement when they catch their first big fish.

“Without regulations, anyone could overfish. We want to protect fish stocks to ensure the future of the commercial fishing industry and the sport.”

Conservation officer responsibilities in patrolling the commercial fishing industry include inspecting nets, docked vessels and commercial fish facilities and enforcing laws against illegal fishing activity involving unlawful gear, fishing out of season, the illegal taking of species and sizes, overharvesting fish and aquatic invasive species.

Additionally, conservation officers must be prepared to manage any kind of situation that occurs on the water, keeping in mind that they may be miles from shore.

Great Lakes Enforcement Unit officers on patrol are shown.

A family tradition

Thousands of commercial fishing licenses used to represent the employment of tens of thousands of individuals active in Michigan’s commercial fishing industry.

“In 1967, approximately 400 fishers grossed $10,000-$12,000 per year,” said Gerlach, a veteran conservation officer with more than 32 years of experience. “By 1977, anglers fishing under roughly 140 commercial fishing licenses were grossing $70,000 per year, each.”

In 2017, the total value of the take for state-licensed commercial fishers was $4 million.

Today, there are 49 state commercial fishing licenses, which tend to be passed down within longtime commercial fishing families, generation to generation. New commercial fishing licenses are no longer issued.

Protecting the resource

Seth Herbst, a DNR aquatic species and regulatory affairs unit manager, provided some historical context of the industry.

“In the late 1800s and early 1900s, fish populations in the Great Lakes were plentiful and commercial fishing flourished. However, through time, fish populations declined as the result of overfishing,” Herbst said. “The threats to fish populations in the Great Lakes continued because of the introduction of invasive species and pollution concerns. These threats led to population declines and dramatically reduced commercial harvest. The current fishery is a fraction of what it was historically, but threats to fish populations persist.”

Michigan’s current commercial fishing laws date back to 1929, when the Michigan Legislature enacted statutes that required licenses, created a fee structure, regulated how, when, where and what fish species could be taken, set minimum size limits, mandated harvest reporting and established penalties for those caught violating the law.

“Today, the commercial fishing laws are outdated and need to be updated to meet the modern needs of protecting fish populations,” Herbst said. “For example, current fines for any commercial fishing violation results in a maximum fine of $100 – a significant amount of cash 90 years ago, but not a substantial deterrent in 2019.”

Legal buoys and nets are marked and have a tag on them, to identify the license holder.

Illegal fishing activity takes away from the next generation’s ability to enjoy the natural resource and hurts the industry. Overfishing one year can impact the industry for years to come, by decreasing the spawning population.

Conservation officers have established a rapport with many families who possess commercial fishing licenses. Each commercial fish license allows the business to fish a designated section of the Great Lakes, helping to prevent territorial issues and overfishing.

Net minding

On the water, conservation officers check netting activity and any commercial fishing vessels they encounter. The officers use digital plotting charts to mark buoys and nets.

Using advanced sonar and radar technology, conservation officers can distinguish objects in the water, including schools of fish and the different types of nets, such as trap and gill nets.

Legal buoys and nets are marked with a tag, identifying the license holder. This is particularly helpful in identifying signs of illegal fishing activity or in finding an owner if a net becomes unsecured and floats loose, which can create a dangerous situation.

“Unfortunately, nets do break loose from their anchors,” said Lt. Terry Short, another conservation officer with the unit. “Nets that break loose may float a (good) distance from where they originated and can float at or just under the surface of the water, making them very dangerous for boaters and anglers.

“Over the years, there have been a number of incidents involving boaters who have become entangled in stray nets on the Great Lakes. These incidents have resulted in boaters being thrown from their vessels into the water, capsized boats, personal injuries and even fatalities.”

Short emphasizes that it’s important to know where you are boating and being aware of where nets are placed by watching for buoys.

Conservation Officer Marvin Gerlach documents a net that was inspected.

“The water can create visual illusions – particularly when on the Great Lakes,” Short said. “It’s important to have an alert, experienced vessel operator. Always be on the lookout for objects floating at or near the surface of the water and make sure you have a United States Coast Guard-approved life jacket for the activity you are doing.”

Conservation officers emphasize safety as the number one priority for all anglers and boaters.


Boaters, anglers and divers often play an important role in reporting drifting nets or other hazards, which the unit investigates.

On July 12, unit conservation officers pulled approximately 2,000 feet of gill net from a shipwreck in Lake Michigan, located 3 miles offshore from Schoolcraft County.

Divers who had found and reported the net assisted conservation officers by attaching a line to the net and running it to the surface for the officers to pull, using equipment on their patrol vessel.

When conservation officers encounter commercial fishing boats, they inspect the catch, paperwork and equipment.

“The people in this industry have been doing this for such a long time, and for the most part, abide by the regulations,” said Gerlach. “We know most of them, they mostly know us – it’s a business relationship.”

Tribal commercial fishers have more authorized territory where they can fish and are permitted to use additional equipment and tactics. Unit officers work closely with tribal law enforcement to ensure regulations are being followed and to educate non-tribal anglers about each license-holder’s treaty fishing rights.

Back on shore

After the fall fishing season, conservation officers with the unit spend time on land inspecting wholesaler facility records and continue vessel inspections. They also follow-up on any leads of illegal activity they may have suspected when they were on the water.

Great Lakes Enforcement Unit conservation officers on patrol.

In 2018, a federal court case was adjudicated involving a state-licensed wholesaler. The DNR collaborated with the U.S. Fish and Wildlife Service on the multistate, undercover investigation, nicknamed “Fishing for Funds.” The agencies investigated the illegal commercialization of fish from the Great Lakes.

As a result of the two-year investigation, a state-licensed wholesaler pleaded guilty, was sentenced to four months in federal prison and ordered to pay up to $270,000 in restitution for selling over 5,000 pounds of illegally harvested lake trout and falsifying records.

In addition, several other successful prosecutions for various illegal activities that were being conducted within the industry resulted from the investigation.

Working from their offshore office space and in onshore investigations, conservation officers of the DNR’s Great Lakes Enforcement Unit are responsible for protecting the Great Lakes commercial fishing industry for future generations – not just for future anglers, but fish consumers as well.

How to help

Anyone who witnesses or suspects a natural resources violation is asked to report it immediately by calling or texting the DNR’s Report All Poaching hotline at 1-800-292-7800. DNR dispatchers are always available. Individuals reporting tips may remain anonymous and may qualify for a reward if supplied information leads to the arrest and conviction of a poacher.

Michigan conservation officers are fully commissioned state peace officers who provide natural resources protection, ensure recreational safety and protect citizens by providing general law enforcement duties and lifesaving operations in the communities they serve.

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/Note to editors: Contact: John Pepin, Showcasing the DNR series editor, 906-226-1352. Accompanying photos and a text-only version of this story are available below for download. Caption information follows. Credit Michigan Department of Natural Resources, unless otherwise noted.

Text-only version of this story.

Boat: Conservation officers enforce regulations pertaining to state- and tribal-licensed commercial fishers. Responsible for regulating industry rules and laws for all of Michigan’s water in the Great Lakes, Great Lakes Enforcement Unit officers are also responsible for monitoring the commercial fish wholesale operations that occur on land.

Documentation: Conservation Officer Marvin Gerlach documents a net that was inspected.

Flag: The Michigan Department of Natural Resources Law Enforcement Great Lakes patrol boat approaches a commercial fish buoy, indicating that there is a commercial net in the water.

Inspection: Great Lakes Enforcement Unit Conservation Officer Mike Hammill inspects a state commercial fishing boat.

Monitoring: Conservation Officers Marvin Gerlach and Mike Hamill monitor a sonar display to determine what type of net is in the water.

Net check: Conservation Officer Marvin Gerlach prepares to check a commercial fish buoy. Legal buoys are marked with the commercial license-holder’s identification.

Sonar: Using advanced sonar and radar technology, conservation officers can distinguish objects in the water, including schools of fish and the different types of nets, such as trap and gill. Shown in this photo is a trap net, almost 69 feet underwater.

Tag: Legal buoys and nets are marked and have a tag on them, to identify the license holder. Pictured is a tag, attached to a commercial fish buoy.

Windshield: Conservation officers in the Michigan Department of Natural Resources’ Great Lakes Enforcement Unit often log 16-hour shifts, traveling up to 150 miles in the patrol vessel they refer to as their “office.”/

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