کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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4429975 | 1619840 | 2011 | 11 صفحه PDF | دانلود رایگان |

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 3.1 mg/L and 15 streams experienced DO less than 4.8 mg/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.
► Spawning success of fathead minnows decreases with increasing specific conductance.
► Spawning success of fathead minnows decreases with decreasing dissolved oxygen.
► Low dissolved oxygen occurred at 15 of 27 streams monitored in Eastern Wisconsin.
► Degradation of stream water- and sediment quality occurs with increasing urban development.
► An effective in situ spawning assay for fathead minnows was developed.
Journal: Science of The Total Environment - Volume 409, Issue 22, 15 October 2011, Pages 4847–4857