Five species of lampreys are found in the upper three Great Lakes. All species require certain physical factors for successful spawning such as suitable bottom substrates, water velocities, and temperatures. Nest construction (usually started by males) and spawning behavior are similar although some differences exist. In sea lamprey an average spawning act lasts about 2–5 s and is repeated every 4–5 min; generally nesting is monogamous with little polyandrous nesting (1.2–5.0%); average egg production is about 60 000 eggs. An estimated 86% of the eggs of sea lamprey are not deposited in the nests; however, the fertilization and survival of eggs deposited in the nest is high and may approach 90%.Key words: Petromyzon marinus, Ichthyomyzon unicuspis, I. castaneus, I. fossor, Lampetra lamottei, spawning requirement, nest construction, fecundity, nest productivity, water temperature

Hammond Bay Biological Station, Millersburg, Michigan 49759THE GENERAL LIFE HISTORY of larval sea lampreys (Petromyzon marinus Linnaeus) has been described [1, 6]. After hatching, the larvae burrow into the muddy bottom of streams where they ingest plankton, mud, and organic detritus. Sea lamprey larvae live in the mud for several years before they metamorphose into the freeswimming, parasitic stage that feeds on the blood and liquefied tissues of fish.Prior to the discovery of a selective sea lam-

The sterility method of pest control could be an effective tool in the sea lamprey (Petromyzon marinus) control program in the Great Lakes. Some of the requirements for its successful application have been met. A field study demonstrated that the release of male sea lampreys, sterilized by the injection of 100 mg/kg of P,P-bis(1-aziridinyl)-N-methylphosphinothioic amide (bisazir), will reduce the number of viable larvae produced. The actual reduction in reproductive success that occurred was directly related to the ratio of sterile to normal males in the population. The technique can be used in many ways in an integrated control program and has considerable potential for the more effective control of the sea lamprey. Eradication is a distinct possibility.Key words: sea lamprey, Petromyzon marinus; pest control, fish control, sterile-male technique, sterilization, chemosterilants, bisazir, Great Lakes

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