Ann E. Bowles
Hubbs-Sea World Res. Inst., 2595 Ingraham St., San Diego, CA 92109
Models for protecting marine mammals from noise have been suggested that
are analogous to human noise criteria, specifically (1) weighting functions
that model species-specific auditory threshold functions (analogous to
A-weighting); (2) threshold models for predicting the proportion of individuals
that avoid a noise (analogous to the Schulz model of annoyance); and (3) the
equal-energy hypothesis for predicting hearing loss. Models for reducing sleep
interference, speech interference, and attention deficits might also be
applicable. All these models will be reviewed. Unfortunately, human noise
criteria do not apply to a number of effects that could occur in free-ranging
marine mammals. Noise could affect nonauditory physiology. Noise could also
mimic natural sounds (e.g., seismic impulses that are similar to tail beats),
or attract marine mammals into dangerous areas (e.g., attracting killer whales
to fishing gear). Given the paucity of research available on noise effects in
marine mammals, standards may be difficult to establish, although they are
badly needed. At present, management agencies have adopted extremely
conservative noise criteria. The experience of regulating noise in human
communities suggests that such stringent criteria cannot be enforced
consistently. Solutions that have proved practical for human communities will
be reviewed.