Audiogram and auditory critical ratios of two Florida manatees (Trichechus manatus latirostris)

Abstract

This Corrigendum relates to J. Exp. Biol. 215, 1442-1447 The authors misunderstood JEB's policies on citing non-peer-reviewed literature, and failed to cite the dissertation of Gerstein (Gerstein, 1999), who also measured critical ratios in two captive manatees.Gerstein measured critical ratios using both pulsed and continuous (4s) tones in the presence of 1/3-octave wide masking noise using two different noise levels. The critical ratios were lower for the pulsed tones than the continuous tone. Although we did not test the same frequencies, our measurements of critical ratios in two other manatees were similar or lower for similar test frequencies for the continuous tone. For example, we measured critical ratios from two manatees at 4kHz of 30.8 and 29.9dB, while Gerstein measured critical ratios at 3kHz of 31 and 34dB. At 16kHz we measured critical ratios of 27.0 and 28.1dB, while Gerstein measured critical ratios of 38 and 42dB at 18kHz. The results Gerstein obtained for the pulsed tones were closer to the critical ratios we measured with the 1s tone.

Bottlenose Dolphins and Antillean Manatees Respond to Small Multi-Rotor Unmanned Aerial Systems

“…The likelihood of detection of this noise, once it penetrates the water's surface, may be increased by reflection and refraction of the rotor noise off the seabed and surface (Erbe et al, 2017). Recent acoustic experiments with UAS (e.g., Christiansen et al, 2016b;Erbe et al, 2017), coupled with the established hearing capabilities of the West Indian manatee (Gerstein et al, 1999;Gaspard et al, 2012) and bottlenose dolphin (Johnson, 1967), indicate that the three aircraft used in this study produce both in-air and underwater sounds that are audible to both species. However, tests of different multi-rotor UAS models suggest that aircraft noise is unlikely to affect most marine mammals when they are underwater, both because the noise is masked by in-air ambient noise and because most of the sound energy fails to penetrate the water's surface (Christiansen et al, 2016b;Erbe et al, 2017).…”

Ontogenetic investigation of underwater hearing capabilities of loggerhead sea turtles (Caretta caretta) using a dual testing approach

“…Operant and classical conditioning techniques have been successfully applied to fishes, marine mammals and sea turtles to determine hearing capability ranges and maximal sensitivity ranges (e.g. lowest detectable level of a given stimulus or absolute threshold) (Patterson and Gulick, 1966;Popper, 1971;Coombs and Popper, 1982;McCormick and Popper, 1984;Yan and Popper, 1991;Kastak and Schusterman, 1998;Gerstein et al, 1999;Nachtigall et al, 2000;Houser and Finneran, 2006;Pacini et al, 2011;Gaspard et al, 2012;Martin et al, 2012). Many studies have involved the collection of both electrophysiological and operant conditioning data for hearing assessment, especially those that focus on marine fishes and mammal groups (Kastak and Schusterman, 1998;Sauerland and Dehnhardt, 1998;Szymanski et al, 1999;Casper et al, 2003;Wolski et al, 2003;Nachtigall et al, 2005;Yuen et al, 2005;Mulsow and Reichmuth, 2010;Reichmuth and Southall, 2011).…”

The relationship between acoustic habitat, hearing and tonal vocalizations in the Antillean manatee (Trichechus manatus manatus, Linnaeus, 1758)

“…The methodology consisted on using a mobile stereo array to locate them using human interaural level difference capabilities. The array was mounted in the kayak and and its design considered the minimum distance between hydrophones for accurate detection of average manatees peak frequency (5 kHz) ( Colbert et al, 2009 ; Gaspard et al, 2012 ; Gerstein et al, 1999 ; Nowacek et al, 2003 ), assuming an underwater sound speed of 1500 m/s ( Carlton, 2012 ). Distance between hydrophones was 86 cm and minimum effective distance for interaural detection is 30 cm.…”

“…Manatees are most sensitive to the range from 16 kHz to 18 kHz ( Gerstein et al, 1999 ; Gaspard et al, 2012 ) but are capable of hearing frequencies up to 90.5 kHz ( Gaspard et al, 2012 ). Manatees have one of the lowest critical ratios reported in mammals, likely an adaptation to noisy environments ( Gaspard et al, 2012 ).…”