Making Friends by Removing Sea Lampreys
BY AARON JUBAR, LUDINGTON BIOLOGICAL STATION
Sea Lamprey control agents use specialized backpack electrofishing equipment to survey Great Lakes streams for larval Sea Lampreys. The gear, which is operated by a single user, passes a relatively low voltage current through the water. The low voltage agitates lampreys out of their burrows in the stream bed. Upon emergence the operator quickly switches to a higher current which immobilizes the larvae, allowing them to be captured. Backpack electrofishing has been utilized for decades to assess streams for Sea Lamprey abundance, guide lampricide applications, and evaluate treatment effectiveness. However, the gear has never been tested as an alternative measure of controlling a Sea Lamprey population, until recently.
In August, Sea Lamprey Control Program (SLCP) staff from the US Fish and Wildlife Service Ludington and Marquette Biological Stations worked alongside personnel from the Pennsylvania Fish and Boat Commission (PFBC) and the Pennsylvania Department of Environmental Protection (PDEP) in an effort to remove Sea Lampreys from a portion of Conneaut Creek, a tributary to Lake Erie. Conneaut Creek has long been a Sea Lamprey producing stream in the Lake Erie basin and was most recently treated with lampricide during May 2013. However, due to PFBC concerns over the Hornyhead Chub, SLCP agreed to not treat a 5.9 mile stretch of Sea Lamprey infested stream not routinely permitted for treatment in the upper reaches of Conneaut Creek. The Hornyhead Chub is common in many portions of the Great Lakes but there are only small populations in two Pennsylvania streams. Given that the effect of lampricide on Hornyhead Chubs is unknown, the PFBC and PDEP requested an alternative method of lamprey removal, specifically backpack electrofishing. “Our main concern is that we don’t want to risk extirpating Hornyhead Chubs from Conneaut Creek and Pennsylvania”, said Doug Fischer, PFBC state Ichthyologist.
The USFWS provided the electrofishing equipment and brought ten SLCP staff to Conneaut Creek. The PFBC and PDEP reciprocated by providing staff for the removal effort. “Working side by side with the Pennsylvania staff was one of the highlights of this project. A partnership was forged and friendships were made”, said Shawn Nowicki, SLCP Larval Control Unit Supervisor. For six days, teams covered all 5.9 miles of Sea Lamprey infested stream, with many areas being electrofished multiple times. The main objective was to remove as many Sea Lampreys as possible. A total of 1,781 Sea Lamprey larvae were removed from the stream. Additionally, the effort removed 202 newly-metamorphosed Sea Lampreys that would have migrated to Lake Erie this fall and destroyed about 40 pounds of sport fish each.
Conneaut Creek also contains abundant American Brook Lampreys, which is a harmless and non-parasitic lamprey species native to the Great Lakes. Throughout the electrofishing removal, efforts were made to return American Brook Lampreys to the stream. Over 3,500 native lampreys were released back into Conneaut Creek unharmed.