Roger A. Bergstedt

New Technique for Sampling Sea Lamprey Larvae in Deepwater Habitats

Evidence for Lack of Homing by Sea Lampreys

Abstract.—Recently metamorphosed sea lampreys Petromyzon marinus were captured in 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 river to continue their migration to Lake Huron to begin the parasitic (juvenile) phase of their life. During the spawning run in spring 1992 when the tagged animals were expected to mature and return to spawn, sea lampreys were trapped in nine tributaries to Lake Huron, including the Devil River; 47,946 animals were examined for coded wire tags, and 41 tagged animals were recovered. None of the 45 mature sea lampreys captured in the Devil River in 1992 were tagged, a proportion (0%) significantly lower...

Evaluation of Two Locations for Coded Wire Tags in Larval and Small Parasitic-Phase Sea Lampreys

Abstract.—Coded wire tags were injected into the dorsal musculature near the insertion of the dorsal fin (dorsal location) and subcutaneously along the ventral midline posterior to the anus (ventral location) of larval and small parasitic-phase sea lampreys Petromyzon marinus. In larvae, tag loss after 1 year was significantly higher (P < 0.01) from the ventral location (18%) than from the dorsal location (1%). Although only 14 tagged larvae metamorphosed during the study, the process did not seem to increase tag loss. Mortality of larvae tagged in either site did not differ from controls (P > 0.57). Parasitic-phase sea lampreys lost no tags from either site through 99 d after tagging. Mortality was high in all...