By Brett Riser, Aquatic Biologist
Calhoun Conservation District and Michigan Natural Shoreline Partnership Educator
Natural shorelines are not only visually appealing but directly benefit many fish species in Michigan. Michigan has more than 11,000 lakes, tens of thousands miles of rivers and streams and 43 percent of the Great Lakes waters within it s borders. Within this vast resource live many fish species that are important to our recreational fisheries. Recreational fisheries are a huge economic engine for the state and provide the largest and highest-value use of Michigan’s aquatic resources as documented in the recently released U.S. Fish and Wildlife report (2011 National Survey of Fishing, Hunting and Wildlife-Associated Recreation) and the Department of Natural Resources 2013-2017 Fisheries Division Strategic Plan, “Charting the Course: Fisheries Division’s Framework for Managing Aquatic Resources”. In addition to the economic benefits of our fisheries, fish populations are often one of several indicators that determine the aquatic health of our water systems.
Critical littoral habitat, riparian habitat, and ecosystem function are altered as a result of shoreline residential development (Engel & Pederson 1998; Francis & Shindler 2009) and many of Michigan’s shorelines have been altered as a result of residential development. Landowners often clear large trees and remove dead trees from the water. Fallen trees in littoral zones, can serve as important refuge for fish (Roth et al. 2007) and complex littoral vegetation comprised of emergent, submerged and free-floating macrophytes (aquatic plants) along the shoreline provide structural complexity that mediates predator–prey interactions by providing refuge for small fishes (Sass et al. 2006).
Michigan’s sunfish species belonging to the family Centrachidae are extremely important to inland fisheries in Michigan and very popular with anglers. The sunfish species are significantly impacted by shoreline development – or the removal of natural shorelines. There are 12 species of Centrachidae in the state and of these: bluegill (Lepomis macrochirus), redear sun fish (Lepomis microlophus), largemouth bass (Micropterus salmoides), and black crappie(Pomoxis nigromaculatus) are examples of species of significant importance to Michigan’s sport fishery that are negatively impacted from shoreline development. These species are abundant in many Michigan lakes and rivers providing residents and visitors many successful angling opportunities.
Effects of development on shorelines extend into the water body itself, and may lead to large shifts in fish communities (Roth et al. 2007). Within developed lakes, black crappie nest adjacent to undeveloped sections of shoreline and associate with macrophytes which are less abundant in developed shorelines (Reed & Pereira 2009). The same trend has been identified for largemouth bass (Scheuerell & Shindler 2004) and bluegill growth rates negatively correlate with shoreline development (Schindler et al. 2000). Largemouth bass in highly developed lakes take longer to enter the fishery and may reach trophy lengths more rapidly in undeveloped systems (Gaeta et al. 2010). Natural shorelines containing vegetation provide needed habitat for the reproduction and survival of these fish species and result in larger fish produced faster within these natural shoreline systems.
These studies indicate an adverse trend in shoreline residential development and its effects on fish communities, especially the Centrachidae (sunfish) family, in Michigan’s lakes and streams. These consequences can be hard to observe over time; and for the riparian landowner to witness how residential development of a shoreline can ultimately negatively affect the ecology of many fish communities is a challenge.
We have observed how natural shorelines benefit many species of wildlife and help to reduce soil erosion along our rivers and lakes. The benefits of natural shorelines extend well into surface waters where this highly desired habitat is extremely valuable, and depended upon, by many of Michigan’s fish species.
Engel, S. & Pederson Jr, J. L. 1998. The construction, aesthetics, and effects of lakeshore development: a literature review. No. Research Report 177. Madison, WI: Wisconsin Department of Natural Resources.
Francis, T. B. & Schindler, D.E. 2009. Shoreline urbanization reduces terrestrial insect subsidies to fishes in North American lakes. Oikos 118: 1872–1882.
Gaeta, J. W., M. J. Guarascio, G.G. Sass, and S.R. Carpenter. 2011. Lakeshore residential development and growth of largemouth bass (Micropterus salmoides): a cross-lakes comparison. Ecology of Freshwater Fish 20:92-101, doi: 10.1111/j.1600-0633.2010.00464.x
Reed, J.R. & Pereira, D. L. 2009. Relationships Between Shoreline Development and Nest Site Selection by Black Crappie and Largemouth Bass. North American Journal of Fisheries Management 29: 943–948.
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