Relationships Between Impervious Surfaces within a Watershed and Measures of Reproduction in Fathead Minnows (Pimephales Promelas)
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- Weber, D.N. & Bannerman, R. Hydrobiologia (2004) 525: 215. doi:10.1023/B:HYDR.0000038868.46128.e4
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Urban regions have a high percentage of impervious surfaces which are critical nonpoint pollution sources. To evaluate the role of impervious surfaces on stream quality, a mobile field station was constructed into which stream water was pumped. Study sites were located within one low, two intermediate and two high percent impervious surface watersheds. Stream water entered three 20-gallon, flow-through aquaria which were divided by 1/8′′ mesh plastic screen into four equal compartments, each containing one male-female fathead minnow breeding pair (n= 12 pairs), and one 4′′ diameter PVC tube (4′′×4′′, cut lengthwise) as a breeding substrate. Temperature within the mobile unit (18–25 °C) maintained by air conditioners or heaters; water temperature in the aquaria (20–24 °C) maintained by aquarium heaters. Daily observations included: reproductive behavior, development of male secondary sexual characteristics, and egg counts. Time spent conducting nest and/or egg care activities, average daily spawn attempts, development of male secondary sexual characteristics (tubercles, dorso-ventral banding, head and body coloration) and male-initiated chasing of female were directly related to percent impervious surface in the watershed (ANOVA, p < 0.05). While spawning frequency and average day to first oviposition were not significantly different between study sites, average daily egg count, number of pairs breeding per day and number of eggs per breeding pair were all associated with land use patterns (ANOVA, p < 0.05). Using reproductive measures in a mobile field station show promise as a flexible method of evaluating water quality in watersheds in urban and urbanizing regions.