Offshore Wind Power Projects in the Great Lakes - Ministry of ...

Offshore wind power projects in the Great Lakes: Background and science considerations for fish and fish habitat
Previous experiences within the Great Lakes have demonstrated that artificial reefs located in 4 -
7.5 m of water are ideal for many centrarchid species including bass, bluegill and crappie
(Creque et al. 2006; Lynch & Johnson 1988). Conversely, artificial reefs that are situated further
offshore are susceptible to unstable thermal habitats making them unsuitable as habitat for these
species (Creque et al. 2006). To keep warm water fish concentrated around a reef complex even
when thermal stratification occurs in deeper areas, it has been suggested that artificial structures
could be placed in rows that extend from shallow to deeper water so that fish can move into
shallower or more oxygenated waters as necessary (Bolding et al. 2004). These examples
demonstrate that knowledge of local and seasonal conditions, as well as an understanding of the
physiological tolerances of target fish species to different temperature or dissolved oxygen
conditions will be essential in selecting suitable sites for artificial habitat enhancement projects.
Artificial structures generally work best to concentrate bottom and structure-oriented species,
territorial species, or obligate reef spawners. Through monitoring studies of nearshore artificial
structures, Great Lakes fish species that have been found to be attracted to habitat modifications
that include riprap, steel piling, concrete or rock rubble, cobble and other materials include
walleye, mottled sculpins, yellow perch, smallmouth bass, rock bass, largemouth bass, lake trout,
lake whitefish, spottail shiner, white sucker, white crappie and round gobies, among others
(Bolding et al. 2004; Fitzsimons 1996; Herdendorf 1985; Jude & DeBoe 1996; Rutherford et al.
2004). In contrast, structure in nearshore environments doesn’t usually drive the presence of
open-water or pelagic species like salmonids, for example. Clearly, prior knowledge of which
fish species exist within the system and are likely to inhabit or utilize specific project areas is
necessary in order to ensure greater chances of success in attracting fish to the artificial
structures (Wills et al. 2004). Similarly, an understanding of the specific life history and habitat
requirements of possible inhabitants will be important in the selection of appropriate scour
protection material type, size and design, as well as in the design or layout, and location of
turbine arrays.
Lake trout habitat restoration
Because there has been a lot of emphasis in recent years to restore spawning populations of lake
trout throughout the Great Lakes, and because offshore wind turbine foundations and scour
protection materials might be located in areas suitable for lake trout spawning habitat, it is worth
Aquatic Research and Development Section 50