Sea lamprey (Petromyzon marinus) size trends in a salmonid stocking context in Lake Superior

• Published in: Canadian journal of fisheries and aquatic sciences Vol. 62; no. 10; pp. 2354 - 2361
• Main Authors: Jorgensen, Jeffrey C, Kitchell, James F
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada NRC Research Press 01.10.2005; National Research Council of Canada; Canadian Science Publishing NRC Research Press
• Subjects: Animal populations; Animal, plant and microbial ecology; Applied ecology; Bayesian analysis; Biological and medical sciences; Conspecifics; Density dependence; Environmental aspects; Exploitation and management of natural biological resources (hunting, fishing and exploited populations survey, etc.); Fecundity; Feeding rates; Fish; Fishes; Freshwater; Fundamental and applied biological sciences. Psychology; Lakes; Mortality; Oncorhynchus; Petromyzon marinus; Petromyzontidae; Relative abundance; Salmon; Salvelinus namaycush; Sea lamprey; Size; Spawning; Species composition; Wildlife management; Lake Superior; Great Lakes of America; North America; America; Canada; North America, Superior L; Canada, Ontario, Superior L; Agnatha; Freshwater environment; Restocking; Salmonidae; Aquatic environment; Vertebrata; Pisces; Developmental stage; Fry; Petromyzon marinus; Stock
• ISSN: 0706-652X; 1205-7533
• DOI: 10.1139/f05-145

Fish community objectives for Lake Superior call for restoration such that it resembles its historical species composition, to the extent possible, yet allow for supplementation of naturalized Pacific salmonids (Oncorhynchus spp.). To achieve these goals, managers strive to control the sea lamprey (Petromyzon marinus) to levels that cause insignificant (<5%) mortality to host species. While control efforts have been successful, sea lamprey size has increased during the control period. We analyzed long-term sea lamprey size trends and found a significant increase from 1961 to 2003 (F = 36.76, p < 0.001, R 2  = 0.473). A local regression revealed two significant size increase periods. We used Bayesian model averaging to find the relationship between sea lamprey size and the stocking of salmonids (lean lake trout (Salvelinus namaycush) and Pacific salmon). Bayesian model averaging identified 91 models, and several regressors were common features in many of the models. Sea lamprey weight was related to stocked lake trout lagged 3, 9, 11, and 13 years, and stocked Pacific salmon lagged 4 years. If sea lampreys can achieve larger sizes attached to Pacific salmonid hosts, and thus inflict more damage, there may be a trade-off for managers in achieving the fish community objectives for Lake Superior.