The process of Commercial Harvest explained

The main method for commercially harvesting minnows in Michigan involves a seine net although glass and wire minnow traps are occasionally used as well. Seining involves a vertical net with floats on the top and weights on the bottom. It is pulled by two people through the shallow water toward shore. Think of a net on a tennis court only a little taller and with very fine mesh. Commercial minnow seines are restricted to no longer than 125 feet and a height of 16 feet. Harvesters are also limited by law where they can use their seines but all the Great Lakes and most non-trout inland waters are open to seining.

pulling a seine tight
A seine pulled tight to shore that contains minnows for sorting and harvest

In addition to seine nets, harvesters can also use small glass or wire traps to catch their minnows. While less popular than seines, traps allow harvesters another option. In certain waters of the state where seine use is prohibited (trout streams, for instance), trapping minnows is the only legal harvest method available.

Once the seine has been pulled the minnows caught need to sorted and graded. They are sorted by physical examination and any non-target fish (usually juvenile yellow perch or small shad) are removed from the catch and released. This is also the time to keep an eye out for any gobies or other aquatic invasive species that need to be removed from the catch and discarded. The process of sorting the catch and removing non-target species can take several hours depending on the size of the harvest and the amount of undesirable fish in the net. After the catch has been effectively sorted and only commercial bait species remain, the minnows are graded into size categories, usually small, medium and large. In the bait trade, the different sizes are sold for the specific fisheries. Emerald shiners are sold as "perch minnows" or "walleye minnows" depending on their size while spottail shiners are sold as popular bait for lake trout. Suckers are commonly used for northern pike fishing with tip-ups in the winter or under a bobber during the open water season.

sorting minnows into a grader
Sorting the minnows into the grader for separation by size

picking out a yellow perch from net of minnows
Physically picking and releasing non-target yellow perch from the catch

After the minnows are sorted and graded, they are moved by five gallon buckets to a live truck for hauling. The trucks vary by owner but are often equipped with several oxygenated holding tanks of water that can be used transport the bait to holding ponds or directly to retail outlets around the state.

putting minnows into a hauling truck
Putting minnows into a typical live hauling truck with a flat bed and water tanks

Once harvested, keeping bait alive long enough to sell can be difficult depending on the season, weather and temperature. In the spring and summer minnows don't keep long in captivity, so at those times of the year, the catchers-wholesalers will usually take their bait directly to retail outlets upon harvest. In the late fall, however, as temperatures drop bait can be kept alive much easier in manmade ponds owned or rented by minnow wholesalers. Because of the ease with which minnows can be ponded and kept alive during the winter, their tendency to school close to shore in large number in the fall, and the difficulty catching minnows once lakes ice over in the winter, harvest in Michigan is usually at its peak during November.

commercial harvest chart
Total gallons of minnows commercially harvested by month 2011-2015

With most wholesales ponding the minnows they harvest in November wholesalers will hold anywhere from a couple thousand gallons up to 10,000 thousand gallons of minnows for the winter months. With each gallon of minnows containing 700 to 1,000 fish, the large wholesalers will usually pond 1.5 to 7.5 million individual fish. The amount each wholesaler will hold depends on the size of their pond, the number of retail stores buying from them, and the expected severity of the winter. The colder the winter, the more ice fishing will occur. Catching the minnows in bulk like this in November and ponding them alive allows for a prolonged and steady distribution of live bait over the winter months to meet the heavy demand of Michigan's ice fishery.

pond used for holding minnows in winter
Typical pond used by the bait industry to hold minnows for the winter ice fishery