Article

Anatomical predictions of hearing in the North Atlantic right whale

Woods Hole Oceanographic Institution, Woods Hole, Massachusetts
The Anatomical Record Advances in Integrative Anatomy and Evolutionary Biology (Impact Factor: 1.34). 05/2007; 290(6):734 - 744.
Source: PubMed

ABSTRACT Some knowledge of the hearing abilities of right whales is important for understanding their acoustic communication system and possible impacts of anthropogenic noise. Traditional behavioral or physiological techniques to test hearing are not feasible with right whales. Previous research on the hearing of marine mammals has shown that functional models are reliable estimators of hearing sensitivity in marine species. Fundamental to these models is a comprehensive analysis of inner ear anatomy. Morphometric analyses of 18 inner ears from 13 stranded North Atlantic right whales (Eubalaena glacialis) were used for development of a preliminary model of the frequency range of hearing. Computerized tomography was used to create two-dimensional (2D) and 3D images of the cochlea. Four ears were decalcified and sectioned for histologic measurements of the basilar membrane. Basilar membrane length averaged 55.7 mm (range, 50.5 mm–61.7 mm). The ganglion cell density/mm averaged 1,842 ganglion cells/mm. The thickness/width measurements of the basilar membrane from slides resulted in an estimated hearing range of 10 Hz–22 kHz based on established marine mammal models. Additional measurements from more specimens will be necessary to develop a more robust model of the right whale hearing range. Anat Rec, 290:734–744, 2007. © 2007 Wiley-Liss, Inc.

0 Bookmarks
 · 
124 Views
  • Bioacoustics 01/2010; 19(3):225-264. · 0.73 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This project capitalized on and extended data, methodologies, and partnerships formed under the ONR funded Effect of Sound in the Marine Environment (ESME). The work comprised two years of collaborative effort focusing on sophistication and refinement of the baseline auditory model developed previously by these team members under ESME and employed the same model architecture and organizational structure that proved successful in the ESME project. The impact modeling effort developed a modular approach paralleling that of the ESME projects in order to permit compatibility with the on-going ESME effort as it develops. The specific objective of this project was to develop biophysically based models of the acoustic power flow from the water, through the tissues of the head and middle ear, into the cochlea, and ultimately to the sensory receptor cells (hair cells). These models allow us to estimate audiograms for multiple odontocete species from anatomical and mechanical measurements and to predict the excitation pattern within individual cochlea for a range of acoustic inputs as well as modeling stresses and strains on key cochlear tissues from over-stimulation.
    06/2006;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Differing physical characteristics and levels of biological, environmental, and anthropogenic sounds contribute in varying levels of noise in different ocean environments. As a result, animals migrating over large ranges or widely distributed species are now exposed to a myriad of different acoustic environments, within which they must navigate, forage and reproduce. Given current increases in low-frequency (< 1000 Hz) anthropogenic noise, there is concern that resultant masking of communication and naturally occurring sounds may stress cetaceans already facing other forms of habitat degradation. As a critical first step to understanding the acoustic environments of coastal marine ecosystems, we examined month-long acoustic data from ten sites along the U.S. east coast that are either designated critical habitats or located along the migratory corridor of the North Atlantic right whale (Eubalaena glacialis): Gulf of Maine, Jeffreys Ledge, Massachusetts Bay, Cape Cod Bay, New York, New Jersey, North Carolina, South Carolina, Georgia (North), and Georgia (South). Data were collected using hydrophones positioned at depth to evaluate differences in the acoustic environment at these sites. High noise levels were observed at both major (New York, Boston) and non-major (Georgia) shipping ports located in or near the areas of study. Of the ten study sites, New Jersey and New York experienced the highest equivalent sound levels, while South Carolina and the Gulf of Maine presented the lowest. The majority of noise variability was found in low-frequency bands below 500 Hz, including the 71–224 Hz communication range utilized by long distance, contact-calling right whales and many other whale and fish species. The spatio-temporal variability of anthropogenic noise can be viewed as a form of habitat fragmentation, where inundations of noise may mask key sounds, resulting in a loss of “acoustic space” (overlapping frequency band and time of a whale’s vocalization), which could otherwise be occupied by vocalizations and other acoustic cues utilized by cetaceans. This loss of acoustic space could potentially degrade habitat suitability by reducing the geographic distance across which individuals acoustically communicate, and ultimately, over long timescales, disrupt aspects related to their natural behavior and ecology. Because communication plays a vital role in the life history of cetacean species, understanding temporal and geographical differences in ambient noise as part of cetacean ecology and habitat may elucidate future conservation strategies related to the assessment of noise impacts.
    Ecological Informatics 05/2014; · 1.98 Impact Factor

Full-text (3 Sources)

Download
126 Downloads
Available from
May 28, 2014