Crews will survey streams to find lampreys
ESCANABA — The continuing battle against sea lampreys soon will come to locations in the local area. A U.S. Fish and Wildlife Service assessment crew will conduct work on the Days, Ford, Ogontz, Portage and Tacoosh Rivers in Delta County Aug. 22-30 to estimate the abundance of sea lampreys. The information gathered will be used to determine the need for sea lamprey control.
A first step in the control of sea lampreys is to survey streams tributary to the Great Lakes to determine the presence of lamprey larvae. Sea lampreys invaded the Great Lakes during the 1920s and have been a permanent, destructive element of the fishery ever since. Sea lampreys attach to fish with a suction cup mouth, rasp a hole though the fish’s scales and skin, and feed on blood and body fluids. The average sea lamprey will destroy up to 40 pounds of fish during its parasitic phase.
Sea lamprey larvae hatch from eggs laid by adult lampreys in gravel nests, and drift into silty bottom areas where they burrow and live for several years. Also, larvae sometimes drift out of streams and settle in the immediate offshore areas near stream mouths. Failure to detect and subsequently eliminate larvae allows the lampreys to transform into parasitic adults and kill Great Lakes fish.
Fishery biologists and technicians conduct surveys for sea lamprey larvae in hundreds of Great Lakes streams each year. Most surveys are conducted by electrofishing, but in deep waters crews use Bayluscide 3.2 percent Granular Sea Lamprey Larvicide, a lampricide approved by the U.S. Environmental Protection Agency and Health Canada Pest Management Regulatory Agency. This lampricide is specially formulated onto sand granules and covered with a time-release coating. The formulation is sprayed over a measured surface area of water where it sinks to the bottom, rapidly dissolves, and causes the larval sea lampreys to leave their burrows and swim to the surface where they are collected.