Going to Scale: Broadening Marine Mammal Noise Exposure Criteria for Behavioral Responses

Abstract

There has been considerable interest in and advances made in both measuring the effects of noise on the behavior of marine mammals and synthesizing results into response thresholds and/or probabilistic functions used in noise criteria. Many of these approaches apply severity 'scales' with presumed gradation of response severity to evaluate specifically identifiable responses in individual or groups of animals exposed in discrete, acute exposure conditions. There has also been considerable and important research looking at disturbance on seasonal or annual timescales for local or regional populations exposed to broader scale or sustained disturbance. However, as yet there has been limited systematic effort to establish behavioral response criteria for these scales. Such criteria, which are certainly needed in many management jurisdictions around the world, will require fundamentally different approaches, metrics, and outputs than acute noise criteria. This paper will consider several possible new approaches and recommend specific steps to begin developing noise criteria for broader, and in some ways more realistic, spatial and temporal scales. Keywords: marine mammals, noise, behavior, response, severity, criteria