title: The ambient acoustic environment in Laguna San Ignacio, Baja California Sur, Mexico.
abstract: Each winter gray whales (Eschrichtius robustus) breed and calve in Laguna San Ignacio, Mexico, where a robust, yet regulated, whale-watching industry exists. Baseline acoustic environments in LSI's three zones were monitored between 2008 and 2013, in anticipation of a new road being paved that will potentially increase tourist activity to this relatively isolated location. These zones differ in levels of both gray whale usage and tourist activity. Ambient sound level distributions were computed in terms of percentiles of power spectral densities. While these distributions are consistent across years within each zone, inter-zone differences are substantial. The acoustic environment in the upper zone is dominated by snapping shrimp that display a crepuscular cycle. Snapping shrimp also affect the middle zone, but tourist boat transits contribute to noise distributions during daylight hours. The lower zone has three source contributors to its acoustic environment: snapping shrimp, boats, and croaker fish. As suggested from earlier studies, a 300 Hz noise minimum exists in both the middle and lower zones of the lagoon, but not in the upper zone.
authors.affiliation: Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, Mail Code 0206, La Jolla, California 92093, USA.
authors.forename: Kerri D
authors.initials: KD
authors.lastname: Seger
authors.affiliation: Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, Mail Code 0206, La Jolla, California 92093, USA.
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Thode
authors.affiliation: Cetacean Research Association, 14700 Springfield Road, Darnestown, Maryland 20874, USA.
authors.forename: Steven L
authors.initials: SL
authors.lastname: Swartz
authors.affiliation: Laboratorio de Mamiferos Marinos, Universidad Autónoma de Baja California Sur Carretera Sur, km 5.5, Apartado Postal 19-B, 23080, La Paz, Mexico.
authors.forename: Jorge R
authors.initials: JR
authors.lastname: Urbán
mesh_terms: D000162:Acoustics / Q000295:instrumentation; D000818:Animals; D061006:Bays; D033364:Decapoda / Q000502:physiology; D004777:Environment; D005399:Fishes; D008800:Mexico; D012621:Seasons; D012767:Ships; D013016:Sound; D014907:Whales