EVIDENCE FOR LACK OF HOMING BY SEA LAMPREYS

Recently metamorphosed sea lampreys Petromyzon marinus were captured i n the Devil River, a tributary to Lake Huron, during summer and autumn 1990. They were tagged with a coded wire tag and returned to the rive r to continue their migration to Lake Huron to begin the parasitic (ju venile) phase of their life. During the spawning run in spring 1992 wh en the tagged animals were expected to mature and return to spawn, sea lampreys were trapped in nine tributaries to Lake Huron, including th e Devil River; 47,946 animals were examined for coded wire tags, and 4 1 tagged animals were recovered. None of the 45 mature sea lampreys ca ptured in the Devil River in 1992 were tagged, a proportion (0%) signi ficantly lower than the proportion of the recently metamorphosed sea l ampreys tagged in 1990. The distribution of tag recoveries among strea ms lakewide, however, was proportional to catch. Tagged sea lampreys d id not appear to home, but instead seemed to select spawning streams t hrough innate attraction to other sensory cues.