Why should fisheries professionals care about instream flow and water level conservation?

Abstract Conservation of instream flows and water levels (instream flows) are vital to sustaining healthy aquatic, riparian, and terrestrial ecosystems. Natural instream flow regimes provide habitat and life history cues, sustain ecological communities, influence water temperatures and other water quality attributes, and affect geomorphic processes. Changes in flow and water level timing, duration, rate of change, magnitude, and frequency can affect the ecological characteristics of water bodies by altering habitat and changing temperature and sediment regimes, ultimately leading to changes in faunal biomass and diversity that may be viewed as positive or negative depending on resource management objectives. Although water quantity-related uses of surface and groundwater in the United States are regulated to varying extents, excessive anthropogenic flow and water level regime modification has been shown to negatively affect aquatic and terrestrial biota associated with many water bodies. Because of the myriad effects instream flow regimes can have on fish and fisheries management, we aim to provide fisheries professionals with basic information about this topic so that they can pursue better management of instream flow regimes and related issues for their specific fisheries objectives. In this paper, we will focus primarily on lotic systems from a fisheries management perspective, defining instream flow, describing instream flow challenges to fisheries management, and providing brief examples of how some instream flow issues are being addressed in the United States. In closing, we encourage fisheries professionals to learn more about the conservation of instream flow regimes in their local waters and incorporate this knowledge into their research and fisheries management duties. We also encourage them to learn about the Instream Flow Council and American Fisheries Society joint project to establish an instream flow and water level conservation training, research, and development center, the National Center for Ecologically Sustainable Water Conservation and Management.