Effects of habitat change in the St. Marys River and northern Lake Huron on sea lamprey (Petromyzon marinus) populations

Abstract

The abundance of parasitic and spawning-phase sea lamprey (Petromyzon marinus) in northern Lake Huron increased by more than fourfold from 1978 to 1985, remaining high through 1993. We determined whether (i) instream rehabilitation in the St. Marys River, (ii) improvements in larval habitat quality in the St. Marys River, or (iii) increased forage fish biomass and salmonid stocking in northern Lake Huron could account for this population increase. We found no significant changes in larval sea lamprey abundance in the St. Marys River from 1971 to 1992. Furthermore, habitat rehabilitation in the St. Marys River occurred 3-5 yr following the increases in adult sea lamprey. Therefore, improvements in spawning and larval habitat quality and quantity could not explain the increase in parasitic-phase sea lamprey. However, bloater chub (Coregonus hoyi), one of the initial targets for recently transformed sea lamprey, increased in biomass between 1978 and 1982. We observed significant, positive correlations between parasitic-phase sea lamprey abundance and bloater chub biomass and lake trout (Salvelinus namaycush) and chinook salmon (Oncorhynchus tshawytscha) stocking rates. We conclude that the increase in parasitic-phase sea lamprey can be attributed to improved survival of recently transformed sea lamprey resulting from greater prey availability.

Evaluation of a Sterile‐Male Release Technique: A Case Study of Invasive Sea Lamprey Control in a Tributary of the Laurentian Great Lakes

“…The St. Marys River is the connecting channel from Lake Superior to Lake Huron (Figure 1). It is the largest tributary to Lake Huron and has been the primary producer of Sea Lampreys in Lake Huron since the 1980s (Young et al 1996). The abundance of parasitic-phase Sea Lampreys in Lake Huron increased during the early 1980s (Young et al 1996;Schleen et al 2003), which was attributed to increases in prey abundance in Lake Huron and the production of Sea Lampreys from the St. Marys River (Eshenroder et al 1987;Young et al 1996).…”

“…It is the largest tributary to Lake Huron and has been the primary producer of Sea Lampreys in Lake Huron since the 1980s (Young et al 1996). The abundance of parasitic-phase Sea Lampreys in Lake Huron increased during the early 1980s (Young et al 1996;Schleen et al 2003), which was attributed to increases in prey abundance in Lake Huron and the production of Sea Lampreys from the St. Marys River (Eshenroder et al 1987;Young et al 1996). Treating the entire St. Marys River with TFM to control Sea Lampreys would have been too costly and technologically challenging due to the river's size (20 times larger in volume than the largest stream ever treated with TFM; Schleen et al 2003).…”