Distribution of Small, Newly Metamorphosed Sea Lampreys, Petromyzon marinus, and Their Parasitism on Menhaden, Brevoortia tyrannus. in Mid-Chesapeake Bay during Winter Months

Abstract

Several examples of young parasitic sea lampreys 6 to 7 inches long attached to Atlantic menhaden about the same length were observed from the channel at a depth of about 70 feet in Chesapeake Bay, Maryland for the first time. They were snagged incidentally to gillnetting operations for striped bass, at bottom temperatures of about 4°C and a salinity of about 16‰. These few records, and reports from fisherman, suggest that the incidence of sea lamprey attachment to menhaden is very low in spite of the high abundance of the hosts. They also show that some newly metamorphosed sea lampreys overwinter in the estuary instead of going to sea in fall as formerly believed, and that they apparently feed parasitically at low winter temperatures.