Friday, February 15, 2013

If wind blows, will fish grow? – Part 2

The presentations and discussions on day 2 of the Offshore Wind – Understanding Impacts on Great Lakes Fishery and Other Aquatic Resources Workshop* addressed issues of aquatic habitats and fish in the Great Lakes. Jason Breck (Univ. Michigan Institute for Fisheries Research) gave a live demonstration of his web-based Lakebed Alteration Decision Support Tool (http://glgis.org/ladst/), which can be used to quickly find suitable habitat for wind farms in the Great Lakes. Drs. Dmitry Beletsky (Univ. Michigan), Nathan Hawley and Jia Wang (NOAA GLERL) reviewed physical characteristics of Great Lakes habitats that would affect wind farm development and operation, including currents, wind, waves, sediment transport, depth, and ice formation and climate.

Interesting biological work was presented by Dr. John Janssen (Univ. Wisconsin at Milwaukee) who has been studying lake trout reproduction on Lake Michigan’s mid-lake reef complex, an area proposed for wind farm development; Chris Vandergroot (Ohio DNR), who discussed intra- and inter-lake movements of walleye that may be affected by wind farm construction or operation, and Dr. Preston Wilson (Univ. Texas at Austin) who is using bubble screens to reduce sound transmission in water generated by wind farm construction and operation. Dr. Winter reported results of experimental work that indicates fish larvae are extremely sensitive to sound generated from construction or operation of wind farms, in contrast to field research reporting relatively benign impacts of wind farms on adult stages of fish. For example, Dr. Arthur Popper (Univ. Maryland) has shown that fish larvae can suffer physical damage and physiological stress from noise generated during wind farm operation. Halvorsen et al. (2012) reported sound thresholds for injury in juvenile Chinook salmon that are exceeded by construction of wind farms. Noise generated by anchoring pylons into hard bottom also was reported on sole larvae.

I left the conference feeling encouraged that there may be enough known about impacts of wind farm development on fisheries resources to make informed decisions about where and how to construct wind farms in the Great Lakes. The European colleagues provided a wealth of information based on experience and research. Many of the fish species discussed by the European visitors are ecologically similar to species that occur in the Great Lakes, including brown trout, zander (walleye), European perch (yellow perch), sculpin (mottled sculpin), and vendace (lake whitefish, cisco). Based on earlier work on development of hydropower and nuclear power plants in the United States, there is a sound modeling framework to infer impacts of wind farm development on fish populations. However, more research needs to be conducted on wind farm impacts on birds, bats and sensitive early life stages of fish. Indeed, concerned citizen Marg Dochoda of Wolf Island Ontario noted plans for wind farm development in Lake Ontario’s eastern shore, where impacts of onshore wind farms on birds already are being observed. Compared to filling relatively few science knowledge gaps, the policy issues of wind farm development for fisheries resources and fisheries are significant and may take longer to resolve.

Fisheries issues in the Great Lakes must be vetted and approved by consent of the International Joint Commission and Lake Councils convened through The Great Lakes Fishery Commission (GLFC). The Council of Lake Committees, through the GLFC, has issued a position statement on wind farm development and Great Lakes fisheries, which notes the potential significant impacts of wind farms on lake habitats, fish and fishers. Comparison of the CLC’s position statement (http://www.glfc.org/boardcomm/clc/position_windpower.pdf) with information provided by European colleagues at the most recent workshop suggests the most important issues to resolve to ensure sustainability of fisheries resources may be addressed by monitoring impacts to fisheries resources before, during and after construction and operation of wind farms, and by gaining consensus from fisheries managers and stakeholders.

Dr. Edward Rutherford

Research Fishery Biologist
NOAA / GLERL

* The main financial partners were the Great Lakes Commission, Great Lakes Wind Collaborative, Great Lakes Fishery Trust, Great Lakes Fishery Commission, DT Energy and National Wildlife Federation.

Thursday, February 7, 2013

If wind blows, will fish grow? – Part 1

The GLC-sponsored Offshore Wind – Understanding Impacts on Great Lakes Fishery and Other Aquatic Resources Workshop* was held on Nov. 28-29, 2012, at NOAA’s Great Lakes Environmental Research Laboratory in Ann Arbor, MI. The workshop was well attended by roughly 50 participants representing resource management agencies, utilities, universities and policy experts.

The first workshop session was devoted to presentations by European experts on wind farm development and impact on marine and freshwater resources. Two of the three invited speakers, Åke Petterson Frikberg and Tore Wizelius, representing Sweden’s Rewind Offshore utility company, gave an informative presentation on development of the first operational wind farm in a freshwater environment. They highlighted how and where in Lake Vanern the wind farm was constructed, and discussed potential impacts of the farm on bird and bats, fishery habitat and fish populations.

Much of their presentation was devoted to issues of construction and cost as they represented the private sector. Åke and Tore discussed tradeoffs between developing wind in freshwater versus salt water. In marine waters, wind farms have stronger, more sustained winds and less interaction with birds or bats, and no ice, but must deal with salt erosion and difficulties in siting farms in deeper depths. They emphasized lowering construction costs as much as possible, which they accomplished by building forms for the pylons onshore and then towing them out to the site by reconverted barge.  Their company also received support of 7% of total costs from the Swedish government. The wind farm was located in shallow waters (4-12 m depth) and over bedrock, which is likely different than where wind farms likely will be sited in the Great Lakes. Construction of wind farms in Lake Vanern was halted during spawning season of the vendace, a member of the coregonid family which includes lake whitefish and cisco.  Åke and Tore noted no significant impacts of wind farms on birds or bats, as these animals do not normally fly at wind speeds > 4m/sec which are most optimal for powering the turbines.

Dr. Erwin Winter, a fisheries scientist from Wageningen University, The Netherlands, reviewed studies of potential impacts of wind farms on marine resources (birds, marine mammals, fish, benthos) in coastal waters of the Netherlands.  He noted there were impacts on bottom fauna and vegetation while construction took place, but not afterward. He noted impacts on phytoplankton biomass due to sediment disturbance, although effects on zooplankton were negligible.  Fish and marine mammals tended to move away from the area during wind farm construction, and returned after construction was completed. In one extensive study, Dr. Winter compared fish abundance, species composition, length and behavior outside and inside of wind farms, and used hydroacoustics to study fish behavior around the wind farm. Results indicated some fish species, principally demersal flatfish, avoided scour bed habitats created by currents swirling around the pylons, while other species such as cod and edible crabs were attracted to the scour beds. There were no detectable effects of the wind farm on the fish community, in fact most species appeared indifferent to its presence. Although the studies described by Dr. Winter were well designed, and used a before/after/control/ impact (BACI) design, they had relatively low statistical power of detecting an impact of wind farms. 

I felt that the presentations by the European visitors addressed several concerns of the Great Lakes community about wind farms. The European studies indicated there were few significant impacts of wind farms on birds, bats, or benthos. Fears about electromagnetic fields generated by power cables were unfounded as the cables were shielded which minimized the electric field. Dr. Winter did note some significant impacts on fauna from underwater sound and habitat disturbance from construction activity, and collision with rotor blades from birds. Potential beneficial impacts of wind farm construction included increase in new reef habitat, and closing areas to fishing near the wind farms.
  
Dr. Edward Rutherford

Research Fishery Biologist
NOAA / GLERL

Part - 2 coming next week!

The main financial partners were the Great Lakes Commission, Great Lakes Wind Collaborative, Great Lakes Fishery Trust, Great Lakes Fishery Commission, DT Energy and National Wildlife Federation.