“Lake sturgeon must be doing something right -- they’re still here,”
said a researcher earlier this summer aboard the Department of Natural Resources’ Channel Cat, a research vessel on Lake St. Clair.

Sturgeon are the largest native species of fish in the Great Lakes. In a recently published book on sturgeon, “The Philosopher Fish,” writer Richard Adams Carey says, “with its long snout and dangling barbells, its lines of armor and its scythe-like tail, the (sturgeon) suggests the result of a night in which whales, sharks, catfish, and – somehow – armadillos all spawned together.” Elsewhere, sturgeon have been described as “a chainsaw with fins.” It has no scales, but rather armor plating that runs in five rows of horny plates, called scutes, down the length of its body. The sturgeon also has no bones, but rather cartilage, like a shark.

The researchers at the DNR’s Lake St. Clair Fisheries Research Station spend late May and early June surveying the lake’s spawning population of sturgeon, a fish that dates to prehistoric times with fossil records showing completely modern forms of sturgeon dating back 100 million years. In fact, sturgeon existed before dinosaurs.

Perhaps one of the best-kept secrets in Michigan is the sturgeon fishery on Lake St. Clair, which researchers say is the best in the Great Lakes. During the late spring, the Channel Cat crew sets lines on known spawning areas in the deltas and deep-water channels of Lake St. Clair and its North Channel. The researchers, through trial and error, have found that round goby, an exotic invasive species, is the preferred bait for the sturgeon.

In less than 24 hours, they return to the lines, pull them up and see if they have hooked some of these incredible fish. The fish that are hooked are removed from the lines, placed in a temporary holding tank on the Channel Cat, and then, one by one are weighed, measured and briefly examined before being released back into the lake.

This “sturgeon rodeo,” as the researchers call it, involves wrangling the sometimes massive sturgeons out of the holding tank and onto a custom-made measuring table. The fish are measured head to tail and around the meatiest part of their body. Then they are examined for silver lamprey scars, which are tabulated, and they are tagged with a metal, numbered tag on a fin. A sample of a fin is cut from the fish, which aids researchers in aging the fish. Finally, the fish is checked with a device to see if a previously-implanted passive integrated transponder (PIT), a radio frequency microchip about the size of a grain of rice, is in the fish. If there is no PIT, one is implanted just under the skin with a hypodermic needle just behind the fish’s head. The PIT enables researchers to track fish on a radio frequency during spawning.

“The direct results of this study are that we are able to justify maintaining a sport fishery for sturgeon in Lake St. Clair,” said Mike Thomas, DNR fisheries research biologist. “Our scientific information shows there is a maintainable population here, but we’re also working on a few mysteries, too.”

Among the mysteries is where the juvenile sturgeon go in the lake and surrounding rivers. Thomas said the DNR is teaming with the U.S. Fish and Wildlife Service (USFWS) during this year’s sturgeon season (July 16 to September 30) to coordinate a study with a few volunteer anglers on the St. Clair River who are catching sturgeon.

Anglers will be asked to call or radio the DNR when they have caught a fish. Researchers in boats will travel to where the angler is, and flush the contents of the fish’s stomach. Learning more about the fish’s diet will help researchers learn more about the habitat of sturgeon. Sturgeon in Lake St. Clair, for instance, have a diet that consists primarily of mayflies, while sturgeon in rivers eat more zebra mussels, said Jim Boase, a USFWS fishery biologist who often works with the crew on the Channel Cat.

Studying sturgeon has offered the DNR and USFWS a unique chance to collaborate. Budget cuts on the federal and state level have made the collaboration necessary, but the agencies share a mutual interest in the fishery of Lake St. Clair. The federal agency also is involved in a project to build artificial spawning reefs in the Detroit River right off of Belle Isle in downtown Detroit.

The artificial sites take the place of many natural spawning sites that have been lost to dredging over the years. One of the spawning sites still used by the fish is off of Algonac near Pearl Beach. In the late 1800s, steam engine ships pulled into a dock there to load salt from an old salt mine. While loading the salt, the ship would jettison coal cinders from its engine compartment into the water -- an industrial process that never would be allowed today that ended up creating the perfect spawning bed for sturgeon. Sturgeon prefer large rocky bottoms with lots of nooks and crannies for spawning.

Sturgeon are slow to reproduce. Female sturgeon in Lake St. Clair start spawning between the ages of 15 and 20 years old. Males start when they are 10 to 12 years old. By comparison, walleye are ready to spawn at 2 to 4 years old.

The sturgeon of Lake St. Clair are threatened most by illegal harvesting, Thomas said. Poaching of larger females outside of season threatens the future of the fishery, and poaching during DNR surveys disrupts valuable research, he said.

The caviar craze of the late 1800s nearly caused sturgeon to go extinct in the Great Lakes. Today, through the DNR’s survey work and fishing restrictions and regulations, Great Lakes anglers are able to enjoy a healthy sturgeon population on Lake St. Clair.