IP11 Investigations of the Columbia River and Estuary (USA)
B113 & B114
8:00 AM - 12:00 PM, Thursday
(IP091) Mechanism for High Prevalence of Skeletal Deformities in Fish from the Newberg Pool, Willamette River.
Curtis, L1, Anderson, K2, Jenkins, J3, Villeneuve, D4, Kent, M5, Markle, D6, 1 Dept. of Environmental and Molecular Toxicology, OSU, Corvallis, Oregon, USA2 Dept. of Environmental and Molecular Toxicology, OSU, Corvallis, Oregon, USA3 Dept. of Environmental and Molecular Toxicology, OSU, Corvallis, Oregon, USA4 Dept. of Environmental and Molecular Toxicology, OSU, Corvallis, Oregon, USA5 Dept. of Microbiology, OSU, Corvallis, Oregon, USA6 Dept. of Fisheries and Wildlife, OSU, Corvallis, Oregon, USA
ABSTRACT- Prevalence of certain skeletal deformities in cyprinid fish is typically 3- to 5-fold higher at Newberg Pool (river miles 26.5 to 55) than upstream near Corvallis (river mile 130). Specifically, site differences occur for prevalence of deformities in vertebral centra and associated structures anteriad of preural centrum 2 (precaudal). A number of toxicants including cadmium and organophosphate insecticides produce vertebral damage in fish. There is public concern that deformities reflect chemical contamination of the river. Concentrations of organophosphate insecticides (OP), persistent organochlorines (OC), and polyaromatic hydrocarbons (PAH) in Willamette River water at Newberg Pool and near Corvallis were measured after collection with semipermeable membrane devices. Concentrations of OC and PAH in water were typically 0.1 to 0.3 and 1 to 2 part per trillion range, respectively. Metals in water were measured after collection with diffusion thin films. Metal concentrations in water were usually below one part per billion. Sediments were analyzed for OP insecticides and OCs. Contaminant concentrations were similar at Newberg Pool and near Corvallis during April - June of 2002 and 2003. Examination of young of the year cyprinid fish collected from these sites in 2002 and 2003 by x-ray, clearing and staining, and histopathology demonstrates very frequent co-localization of parasites with precaudal skeletal deformities. Cysts of a fluke (Anophallus sp.) or histozoimyxozoan spores (probably Myxobolus cyprini) occur in 88- 95 % of these lesions in these lesions in northern pikeminnow and chiselmouth from the Willamette River. Laboratory transmission studies confirm that exposure of early life-stage fathead minnows to fluke cercarie produces skeletal deformities. Higher parasite infestation in fish at Newpool Pool than at Corvallis is an underlying mechanism for higher prevalence of skeletal deformities at that site.
Key words: deformities, pollution, fish, parasites