title: Tumours in white suckers from Lake Michigan tributaries: pathology and prevalence.
abstract: The prevalence and histopathology of neoplastic lesions were assessed in white sucker Catostomus commersonii captured at two Lake Michigan Areas of Concern (AOCs), the Sheboygan River and Milwaukee Estuary. Findings were compared to those observed at two non-AOC sites, the Root and Kewaunee rivers. At each site, approximately 200 adult suckers were collected during their spawning migration. Raised skin lesions were observed at all sites and included discrete white spots, mucoid plaques on the body surface and fins and large papillomatous lesions on lips and body. Microscopically, hyperplasia, papilloma and squamous cell carcinoma were documented. Liver neoplasms were also observed at all sites and included both hepatocellular and biliary tumours. Based on land use, the Kewaunee River was the site least impacted by human activities previously associated with fish tumours and had significantly fewer liver neoplasms when compared to the other sites. The proportion of white suckers with liver tumours followed the same patterns as the proportion of urban land use in the watershed: the Milwaukee Estuary had the highest prevalence, followed by the Root, Sheboygan and Kewaunee rivers. The overall skin neoplasm (papilloma and carcinoma) prevalence did not follow the same pattern, although the percentage of white suckers with squamous cell carcinoma exhibited a similar relationship to land use. Testicular tumours (seminoma) were observed at both AOC sites but not at the non-AOC sites. Both skin and liver tumours were significantly and positively associated with age but not sex.
authors.affiliation: Fish Health Branch, Leetown Science Center, U.S. Geological Survey, Kearneysville, WV, USA.
authors.forename: V S
authors.initials: VS
authors.lastname: Blazer
authors.affiliation: Division of Forestry and Natural Resources, West Virginia University, Morgantown, WV, USA.
authors.forename: H L
authors.initials: HL
authors.lastname: Walsh
authors.affiliation: Fish Health Branch, Leetown Science Center, U.S. Geological Survey, Kearneysville, WV, USA.
authors.forename: R P
authors.initials: RP
authors.lastname: Braham
authors.affiliation: Fish Health Branch, Leetown Science Center, U.S. Geological Survey, Kearneysville, WV, USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Hahn
authors.affiliation: West Virginia Cooperative Fish and Wildlife Unit, U.S. Geological Survey, West Virginia University, Morgantown, WV, USA.
authors.forename: P
authors.initials: P
authors.lastname: Mazik
authors.affiliation: Center for Limnology, University of Wisconsin-Madison, Madison, WI, USA.
authors.forename: P B
authors.initials: PB
authors.lastname: McIntyre
mesh_terms: D000818:Animals; D063646:Carcinogenesis; D003531:Cypriniformes; D005393:Fish Diseases / Q000453:epidemiology* / Q000209:etiology / Q000473:pathology*; D008113:Liver Neoplasms / Q000453:epidemiology / Q000209:etiology / Q000473:pathology / Q000662:veterinary; D009369:Neoplasms / Q000453:epidemiology / Q000209:etiology / Q000473:pathology / Q000662:veterinary*; D015995:Prevalence; D012878:Skin Neoplasms / Q000453:epidemiology / Q000209:etiology / Q000473:pathology / Q000662:veterinary; D014922:Wisconsin / Q000453:epidemiology
keywords: White sucker; environmental health; liver neoplasms; skin neoplasms; tumours