Groundwater and fish—insights from northern North America

Abstract

Fishes inhabiting streams and rivers in the interior of North America experience a continental climate. Water temperatures reach 0 °C in winter and are high in summer. There is a marked seasonal cycle in discharge. These circumstances make groundwater a crucial component of river habitats. Groundwater can influence the distribution, reproductive success, biomass and productivity, behaviour and movements of fishes, and is especially important in winter and summer. Winter flows are minimal and are affected by ice. In winter, the importance of groundwater increases northwards. Groundwater provides overwintering habitat free of subsurface ice and fish may migrate long distances to take advantage of it. The melt season can account for up to half the annual discharge. In summer, groundwater is important for maintaining discharge and moderating stream temperatures. During critically hot weather, groundwater refugia protect species exposed to temperatures approaching their thermal limits. Since groundwater exerts such an important influence on river habitats, its quality, quantity and sustainability should be considered before development proposals are approved which could alter it. Examples of the role of groundwater in the ecology of some species show how localised and critical habitats influenced by groundwater can be, and, in consequence, how necessary it is to protect them. Protection is complicated because groundwater distribution pathways are often unknown and recharge areas may be remote from discharges. Scale becomes important in identifying potential risks to critical stream habitats from all types of landscape modification and water abstraction. Groundwater temperatures reflect mean annual air temperatures and are likely to change as global climates respond to increases in the greenhouse gases in the atmosphere. This could profoundly change critical fish habitats, particularly those at the margins of species distributions or those that are already overcrowded. Such considerations emphasise the importance of developing proper strategies for the conservation of groundwater. Copyright © 1999 John Wiley & Sons, Ltd.

Environmental influences on an exploited anadromous Arctic charr stock in Labrador

“…Deeper winter snowpack also maintains taliks, or unfrozen areas, in lake and river beds that permit linkages between surface and groundwater flows during winter (Prowse, 1990;Allan, 1995). Increased groundwater flows improve winter refugia by expanding the volume of available habitat (Power & Barton, 1987;Power et al, 1999) and can increase water temperatures (Allan, 1995). Although little is known about the exact role of temperature in determining the overwinter condition of salmonids, Elliott (1994) has shown that the proportion of daily energy use available for growth and metabolism in brown trout Salmo trutta L., increases slightly with temperature at the lower end (3-5 C) of the thermal niche.…”

Summer Stream Temperatures Influence Sculpin Distributions and Spatial Partitioning in the Upper Clark Fork River Basin, Montana

“…In our study, Columbia Slimy Sculpin occurred in the coldest reaches, where maximum water temperatures rarely or never reached 22uC, even during the record warm summer of 2007. Rocky Mountain Sculpin tolerated warmer temperatures, including maximum temperatures exceeding 23uC in four reaches and as high as 27.5uC in one reach; however, the fish may have retreated to cooler groundwater-influenced patches in the substrate during very high temperatures (Power et al, 1999). Similarly, Uranidea cognata generally inhabits colder streams, deeper lake habitats, and occurs farther north compared to U. bairdii (Scott and Crossman, 1973;Hubbs et al, 2004).…”

“…In Lolo Creek, about 3 km upstream of the mouth, August water temperature averaged 15.8uC over four summers -1999Chris Clancy, Montana Fish, Wildlife, and Parks, unpubl. data), and in O'Brien Creek, mean August temperature in 2007 was 16.6uC (Adams et al, 2015:table 3).…”

Climate Change Simulations Predict Altered Biotic Response in a Thermally Heterogeneous Stream System

“…At a coarse spatial scale, groundwater can influence the distribution and abundance of aquatic organisms [23], [24] and reduce the occurrence of temperature fluctuations that may result in reproductive failure of certain species [25]. At fine spatial scales, some fishes show behavioral responses to thermal refuges by selecting spawning locations [26], [27], avoiding ice break up and frazil ice [28], or thermoregulating by occupying groundwater influenced areas during warm or cool water periods [16], [19], [20], [29].…”