title: Impacts of nonpoint inputs from potato farming on populations of slimy sculpin (Cottus cognatus).
abstract: The potential influence of agricultural activity, particularly potato cultivation, on slimy sculpin populations (Cottus cognatus) was examined at 19 rivers of New Brunswick, Canada. Comparisons with forested streams resulted in differences in fish density, size, and reproductive performance. Young-of-the-year (YOY) sculpin were present only at two of 11 agricultural sites, though they were present at all nine forested sites. Sediment deposition was greatest at agricultural sites, with increased fine sediments deposited. Larger, coarse sands were deposited at two sites with active forest operations. Temperature had a stronger correlation than sedimentation with sculpin size and density in the agricultural region. Agricultural catchments were warmer than in forested catchments (median = 16.0 and 13.3 degrees C, respectively). Body size of slimy sculpin was correlated positively and YOY densities correlated negatively with temperature, and sites with temperatures > or = 25 degrees C were devoid of YOY sculpin. Our data indicate there is a significant effect of temperature on slimy sculpin populations in rivers of potato farming areas, highlighting the importance of examining indirect factors when investigating possible impacts of nonpoint source agricultural inputs. Indirect factors such as sediment deposition and temperature need to be considered in order to discriminate accurately the chronic impacts of agricultural chemicals on fish populations.
authors.affiliation: Canadian Rivers Institute and Department of Biology, University of New Brunswick, Fredericton, New Brunswick E3B 6E1. m.gray@unb.ca
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Gray
authors.forename: R Allen
authors.initials: RA
authors.lastname: Curry
authors.forename: Kelly R
authors.initials: KR
authors.lastname: Munkittrick
mesh_terms: D000383:Agriculture / Q000379:methods*; D000818:Animals; D049872:Bivalvia; D002104:Cadmium / Q000737:chemistry; D002170:Canada; D004305:Dose-Response Relationship, Drug; D004784:Environmental Monitoring / Q000379:methods*; D005399:Fishes; D019015:Geologic Sediments; D007700:Kinetics; D012989:Soil Pollutants; D011198:Solanum tuberosum; D013696:Temperature; D013997:Time Factors; D014867:Water; D014873:Water Pollutants; D014874:Water Pollutants, Chemical
chemical_list: D012989:Soil Pollutants; D014873:Water Pollutants; D014874:Water Pollutants, Chemical; D002104:Cadmium; D014867:Water