Research
Fish Recruitment and Productivity
Outlook: Changes in Fish Communities and Foodwebs
- Coldwater species of fish such as lake trout, brook trout, and white-fish are likely to decline in southern regions.
- Warm-water species such as smallmouth bass and bluegill are likely to expand northward
- Invasions of warm-water non-native species expected to increase
- Changes in floods may decrease amount of safe breeding sites for amphibians and birds
- The duration of summer stratification will increase, adding to the risk and size of “dead zones”
- Many fish species grow faster in warmer waters, but it remains unknown whether the food web resources they depend on will increase to meet their demands
Forecasts
- Number of Fish by Species
- Size of Fish
- Fish Condition
- Fish Distribution
Projects
In the past, GLERL research focused on factors affecting food web dynamics and structure and function of fish communities has examined impact of changes in lake temperature regimes over space and time. For example, by looking at year-to-year variation in thermal structure of Lake Michigan, GLERL scientists identified an unusually warm year (1998) expected to be similar to future years given predicted warming trends under climate change scenarios. In addition, bioenergetic modeling of such conditions indicated changes in distribution of prey fish and corresponding reduced growth rate potential in Chinook salmon. Such studies of interannual food web dynamics promise to increase insight into the overall impact of climate change on Great Lakes fish communities.
Comparison of water temperatures simulated for base conditions and the year 2090 and measured in the southern basin of Lake Michigan in the years 1996 and 1998
Conceptual demonstration of the effect of changes in the volume of thermal habitat on prey densities
Brandt, S.B, Mason. D.M., McCormick, M.J., Lofgren, B. and T.S. Hunter, 2002, Climate Change: Implications for Fish Growth Performance in the Great Lakes. American Fisheries Society Symposium 32:61-76