Effects of Pile Driving on Fishes
Pe driving in the aquatic environment is a major issue in the U.S. and around the world. Pile driving is required for a wide range of construction activities including building bridges, piers, off-shore wind farms, etc. Several recent papers discuss pile driving and the issues surrounding them in some detail. (To learn more about pile driving and hear pile driving sounds visit Discovery of Sound in the Sea web site.)
Hawkins, A. D. and Popper, A. N. (2017). A sound approach to assessing the impact of underwater noise on marine fishes and invertebrates. ICES Journal of Marine Science, 74:635-651
Popper, A. N., Hawkins, A. D., and Halvorsen, M. C. (2019). Anthropogenic sound and fishes. A Report Prepared for the Washington State Department of Transportation, Olympia, WA.
Popper, A. N. and Hawkins, A. D. (2019). An overview of fish bioacoustics and the impacts of anthropogenic sounds on fishes. Journal of Fish Biology, 94:692-713.
Most earlier studies on pile driving have been difficult to design and, in many cases, poorly executed. It is, in particular, very hard to control the sounds to which fish are exposed from pile driving operations since they are often very large and very expensive, and (understandably), people doing construction need to work as quickly as possible and they cannot easily mange the rate of their pile driving activities to fit an experimental protocol.
In order to understand effects of pile driving on fish, our group developed a lab-based system that would enable us to expose fish to simulated pile driving sounds in the lab, at sound intensities equivalent to those fish would encounter in the wild Moreover, we wanted to be able to control all sound parameters, including sound intensity, number of strikes, inter-spike interval, etc. To do this, we developed a device called the HICI-FT (Figures below) in which the experiments were conducted.
The experiments, in brief, involved exposing fish to impulsive sounds that varied in number and sound level. Fish were then necropsied (animal version of autopsy) to determine effects on body tissues. (It should be noted that all studies were done under strict overview of the university Institutional Animal Care and Use Committee.)
The work done with the HICI-FT included studies on the levels of sound (in terms of sound exposure level - SEL) and number of simulated pile strikes resulted in physical damage to fishes, and we developed dose-response relationships. Our initial work was with Chinook salmon. Briefly, we found that the levels of sound exposure set as interim criteria back in 2008 by the Fisheries Hydroacoustics Working Group (FHWG) were far below levels that actually start to have onset of physical effects on fishes.
Halvorsen, M.B., Casper, B.M., Woodley, C.M., Carlson, T.J., and Popper, A.N. (2011). Predicting and mitigating hydroacoustic impacts on fish from pile installations. NCHRP Research Results Digest 363, Project 25-28, National Cooperative Highway Research Program, Transportation Research Board, National Academy of Sciences, Washington, D.C.
Halvorsen, M. B., Casper, B. M, Woodley, C. M., Carlson, T. J., and Popper, A. N. (2012). Threshold for onset of injury in Chinook salmon from exposure to impulsive pile driving sounds. PLoS ONE, 7(6)
Casper, B. M., Halvorsen, M. B., Carlson, T. J., and Popper, A. N. (2017). Onset of barotrauma injuries related to number of pile driving strike exposures in hybrid striped bass. The Journal of the Acoustical Society of America, 141: 4380-4387 (download publication)
However, we then extended the studies to explore effects on other species and found that the onset of effects varied by species, but all levels were well above those criteria proposed in 2008.
We also found that the species we tested that does not have a swim bladder showed no tissue damage even at the highest sound levels we could produce in the HICI-FT.
Halvorsen, M. B., Casper, B. M., Matthews, F., Carlson, T. J., and Popper, A. N. (2012). Effects of exposure to pile driving sounds on the lake sturgeon, Nile tilapia, and hogchoker. Proceedings of the Royal Society B. 279, 4705-4714
We also examined recovery from effects. We found that fishes recover from all effects in about 10 days after exposure. However, it is very important to note that recovery was done on fish kept in the lab, fed and cared for, and not subject to predation. Similarly exposed fishes in the wild may have reduced fitness, and so be subject to predation.
Casper, B. M., Popper, A. N., Matthews, F., Carlson, T. J., and Halvorsen, M. B. (2012). Recovery of barotrauma injuries in Chinook salmon, Oncorhynchus tshawytscha from exposure to pile driving sound. PLoS ONE, 7(6): e39593.
Casper, B. M. Halvorsen, M. B., Mathews, F., Carlson, T. J., and Popper, A. N. (2013). Recovery of barotrauma injuries resulting from exposure to pile driving sounds in two sizes of hybrid striped bass. PLoS ONE, 8(9): e73844.
Finally, we examined damage to the inner ear and found that inner ear damage only showed up at exposures well above those that result in damage to abdominal tissues.
Casper, B. M., Smith, M. E., Halvorsen, M. B., Sun, H., Carlson, T. J., and Popper, A. N. (2013). Effects of exposure to pile driving sounds on fish inner ear tissues. Comparative Biochemistry and Physiology A, 166:352-360.
