Purdue University

Lake Sturgeon Research

Host-Size Selection and Lethality of Sea Lamprey on Lake Sturgeon
The use of the no observable effect (i.e., no mortality) lampricide treatment protocol to protect lake sturgeon Acipenser fulvescens populations might also increase production of sea lampreys Petromyzon marinus and, consequently, parasitism on lake sturgeon. However, no studies have examined the influence of sea lamprey parasitism on lake sturgeon survival. Because previous model simulations indicate that sea lamprey attacks on adult lake sturgeon adversely affect long-term population viability, understanding is needed of the relations among wounding rate, wound type, and host survival to ensure that sea lamprey control strategies optimize lake sturgeon rehabilitation in the Great Lakes. For this study, we will examine the following objectives: (1) compare the short- and long-term survival of three size groups of lake sturgeon after a single sea lamprey attack; (2) determine the rate of wound healing and scar retention of lake sturgeon hosts following sea lamprey attacks; (3) develop a classification system for the categorization of sea lamprey marks on lake sturgeon. For this experiment, we will use three size classes of lake sturgeon (N = 25 fish per size class; 125 lake sturgeon for this study are currently at Purdue University): (1) small (400 to 599 mm fork length); (2) medium (600 to 799 mm); and (3) large (800 to 999 mm). Each lake sturgeon will be weighed, individually placed in a holding tank with a single, pre-weighed sea lamprey, and the time and location of attachment will be recorded for each pairing. Following detachment, both fish will be re-weighed and the wound type on each lake sturgeon will be classified according to standard criteria. Surviving lake sturgeon will be transferred to recovery tanks at the same temperature as the test tanks to determine delayed mortality during a 14- to 21-d recovery period. Any mortality during this period will be further classified into fish that died from sea lamprey attack or secondary infection. Survivors will be held an additional 60+ days at 10oC to determine the rate of wound healing and scar retention. The number of live and dead lake sturgeon will be examined by size class, and location and duration of sea lamprey attachment. Dead lake sturgeon will also be assessed based on the source and timing of mortality. Sea lamprey data will be examined by weight gain, and location and duration of attachment.

Funding Source: Great Lakes Fishery Commission

Personnel: Holly Patrick (current master’s student)

• Project not yet completed; project completion date: December 2006

Collaborators: William Swink and Anant Bharadwaj

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