I learned that I was mentioned in a May 23 opinion piece in your paper “Help our undersea friends by ending fireworks on the Delaware River.”
While the essay is correct in stating that I have argued that intense underwater sounds have the potential to harm fishes, I have never suggested, as is implied, that sounds in air have the potential to impact fishes.
Indeed, had the author contacted me before writing the essay they would have learned that sound in air “bounces off” the air-water interface, just like light bounces off mirrors. This means that the vast majority of in-air sound energy, even from intense sources such as fireworks, do not get into the water.
And any sound energy getting into the water from the air (as from fireworks) is likely to be very low level due to attenuation by the air-water interface, and below the threshold of hearing for most fish species.
Indeed, American sturgeon do not hear very well, and while American shad hear better than sturgeon, I suspect the sounds would not be loud enough to elicit any substantive response, and certainly not loud enough to harm them in any way. (Note, my lab has investigated hearing sensitivity in both species.)
At the same time, I will agree that one has to be concerned about human-made sounds (generally called anthropogenic sounds) both in air and in water. However, we know very little about how underwater anthropogenic sounds impact fishes (much more is known about effects on marine mammals since they are more “popular” and also protected by U.S. and international legislation).
Indeed, I have argued that everything from boating to offshore wind farm construction to exploration for offshore oil and gas (and much more) has the potential to impact fishes (and, I will add, this includes aquatic invertebrates such as crabs, lobsters, and innumerable more species).
The “bottom line” is that we know very little about this subject, and much more research is needed to really understand the impacts on sturgeon, shad, and all fishes (and aquatic invertebrates).
Indeed, the importance of this is highlighted by the fact that somewhat over 15% of all humans depend on fishes and aquatic invertebrates for their protein, and I suspect this number is only growing.
Arthur N. Popper is a professor emeritus and research professor in the Department of Biology at the University of Maryland.
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