Environmental Variation, Fish Community Composition, and Brown Trout Survival in the Pigeon River, Ottawa County, Michigan
Macdonald, Neil W., Mays, Daniel W., Rediske, Richard R., Ruetz, Carl R.,, III, Michigan Academician
The Pigeon River, a small coolwater stream in western Michigan, has a history of hydrologic, stream habitat, and water quality degradation that led to the loss of its trout population by the late 1980s. After regulatory and watershed management efforts to reduce point- and nonpoint source pollution in the 1990s, the Michigan Department of Natural Resources reinstituted brown trout (Salmo trutta) stocking in 2003, As part of these efforts, we monitored water quality in the Pigeon River each fall between 1996 and 2Q08, and conducted stream surveys in 2006 and 2007 to evaluate the fish community and outcome of trout stocking. Water quality tended to improve and stabilize through time, although point- and nonpoint source pollution still contributed to water quality problems. Hydrologic instability, caused by wetland drainage, agricultural land use, and irrigation withdrawals from the lower mainstream, created periods of environmental stress. As a result, the fish community of the Pigeon River was dominated by common tolerant warmwater species, typical of agricultural watersheds in southern Michigan. Nonetheless, brown trout surviving from initial stockings in 2003 and 2004 had attained lengths of between 18 and 24 inches by 2007, suggesting the thermal regime, water quality, stream habitat, and forage base of macroinvertebrates and small fish were suitable to maintain a stocked brown trout population. Continued efforts to improve water quality, protect instream habitat, reduce high stormflows, and maintain adequate summer baseflows are needed to fully restore environmental conditions for the native fish community and stocked brown trout in the Pigeon River.
Fish communities in many Midwestern streams have been degraded as a result of a variety of anthropogenic factors including agricultural nonpoint source pollution, wetland drainage, stream channel modification, toxic waste discharge, water withdrawal, and exotic species introduction (Karr et al. 1985). Management efforts to improve fish communities in degraded streams often focus on physical or chemical aspects of water quality, even though improvement in these measures may take extended monitoring periods to detect because of the lag time between adoption of management practices and watershed response (Meals et al. 2010). In addition to in-stream water quality, fish community composition is strongly affected by watershed land use (Roth et al. 1996), stream habitat characteristics (Gorman and Karr 1978; Neumann and Wildman 2002), hydrologic stability (Bain et al. 1988; Poff and Allan 1995), and their interactive effects on stream temperature (Poole and Berman 2001). Chemical monitoring alone does not account for the effects of human-induced perturbations such as alterations in flow or physical habitat degradation (Karr et al. 1985), and biotic assessments of fish communities can provide a more integrated view of overall stream condition (Karr 1981; Eklov et al. 1998). Recent efforts to improve the Pigeon River, a small coolwater stream in western Michigan (Zorn et al. 2008; Lyons et al. 2009), provide a case study of both the consequences of past degradation and the ongoing challenges to restoration of water quality, hydrology, and a desirable fish community in a heavily human-perturbed system.
The Pigeon River is a small coastal stream that drains a 16,765 ha agricultural watershed in western Ottawa County, Michigan, and discharges into south-central Lake Michigan (Figure 1). This stream has a typical history of degradation related to the effects of agricultural nonpoint source pollution, extensive drainage of wetlands in the 1920s (Anonymous 1919), stream channelization, and point source discharges, all of which led to a documented decline in its biotic condition by the late 1980s (Creal and Wuycheck 1998), For example, the mainstream of the Pigeon River is designated as a coldwater fishery by the State of Michigan, but cessation of stocking in the late 1960s combined with degraded water quality in the 1980s resulted in the loss of its trout population (PRWAC 1997; Wiley and Seelbach 1998). …