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Mechanical rock grinding in the M ississippi R iver: anthropogenic noise production and implications for the federally endangered pallid sturgeon, S caphirhynchus albus ( F orbes & R ichardson, 1905)
Author(s) -
Hempen G. L.,
Keevin T. M.,
Rodgers M. T.,
Schneider B. M.
Publication year - 2014
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1111/jai.12582
Subject(s) - sturgeon , grinding , endangered species , biology , pulverizer , noise (video) , fishery , environmental science , fish <actinopterygii> , ecology , materials science , habitat , composite material , image (mathematics) , artificial intelligence , computer science
Summary The use of mechanical rock grinding to remove rock pinnacles and outcroppings, considered to be navigation hazards in the M ississippi R iver, was evaluated as a less damaging alternative when compared to the more conventional use of drilling and blasting. The project area contains the federally endangered pallid sturgeon ( S caphirhynchus albus ) and there was concern that intense sound pressure levels ( SPL s) could impact the species. SPL s were measured during production rock grinding ( J anuary 2012, just north of T hebes, I llinois) and compared to those values with SPL s known to cause fish mortality, hearing damage, temporary hearing threshold shifts ( TTS ), and stress. The source SPL s’ maxima for each time block analyzed ranged from 160–172 d B (re 1 μ Pa @ 1 m) at frequencies ranging from 100–1250 H z (1/3‐octave band). The highest source SPL maximum recorded for the sound recording session was 172 dB (re 1 μ Pa @ 1 m) at 1250 Hz. These SPL levels at 1 m from the grinder were well below levels responsible for mortality or noise induced hearing damage. The impact zone for stress (increases in cortisol) was calculated to be within a 9 m radius of the grinder, while the impact zone for TTS was calculated to be within 31 m of the grinder. Considering the small impact zones and continuous noise production during grinding, there is a strong possibility that sturgeon would either avoid or move out of the impact zone.