title: Water- and sediment-quality effects on Pimephales promelas spawning vary along an agriculture-to-urban land-use gradient.
abstract: Many streams in the U.S. are "impaired" due to anthropogenic influence. For watershed managers to achieve practical understanding of these impairments, a multitude of factors must be considered, including point and nonpoint-source influence on water quality. A spawning assay was developed in this study to evaluate water- and sediment-quality effects that influenced Pimephales promelas (fathead minnow) egg production over a gradient of urban and agricultural land use in 27 small watersheds in Eastern Wisconsin. Six pairs of reproducing fathead minnows were contained in separate mesh cartridges within one larger flow-through chamber. Water- and sediment quality were sampled for an array of parameters. Egg production was monitored for each pair providing an assessment of spawning success throughout the 21-day test periods. Incidences of low dissolved oxygen (DO) in many of these streams negatively impacted spawning success. Nine of 27 streams experienced DO less than 3.1mg/L and 15 streams experienced DO less than 4.8mg/L. Low DO was observed in urban and agricultural watersheds, but the upper threshold of minimum DO decreased with increasing urban development. An increase in specific conductance was related to a decrease in spawning success. In previous studies for streams in this region, specific conductance had a linear relation with chloride, suggesting the possibility that chloride could be a factor in egg production. Egg production was lower at sites with substantial urban development, but sites with low egg production were not limited to urban sites. Degradation of water- and sediment-quality parameters with increasing urban development is indicated for multiple parameters while patterns were not detected for others. Results from this study indicate that DO must be a high priority watershed management consideration for this region, specific conductance should be investigated further to determine the mechanism of the relation with egg production, and water- and sediment-quality degrade in relation to urban influence.
authors: U.S. Geological Survey, 8505 Research Way, Middleton, WI 53562, USA. srcorsi@usgs.gov
authors: Steven R
authors: SR
authors: Corsi
authors: Rebecca D
authors: RD
authors: Klaper
authors: Daniel N
authors: DN
authors: Weber
authors: Roger T
authors: RT
authors: Bannerman
mesh_terms: D000818:Animals; D002712:Chlorides / Q000032:analysis; D003530:Cyprinidae / Q000502:physiology*; D004553:Electric Conductivity; D004784:Environmental Monitoring / Q000379:methods* / Q000706:statistics & numerical data*; D005260:Female; D008297:Male; D010063:Ovum / Q000187:drug effects; D010100:Oxygen / Q000032:analysis; D012098:Reproduction / Q000187:drug effects* / Q000502:physiology; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000633:toxicity*; D060753:Water Quality / Q000592:standards*; D014922:Wisconsin
chemical_list: D002712:Chlorides; D014874:Water Pollutants, Chemical; D010100:Oxygen