Ecological Risk To Cetaceans From Anthropogenic Ocean Sound; Characterization Analysis Using A Professional Judgment Approach To Uncertainty

Abstract

The recommendations of anthropogenic ocean sound impact criteria by an expert community of scientists have been monitored over the 10-year period from 1996 - 2006. This dissertation approaches this topic in three ways; 1: by content analyzing 94 peer-reviewed publications specific to this topic (representing 20 countries and 27 species of cetaceans, and virtually all oceans), from which up to fifteen variables were coded for exploratory analysis, 2: by an anonymous Internet survey questionnaire administered to 91 of the 119 authors of these 94 publications, one that was designed to identify common patterns and points of departure in how these expert scientists currently independently and anonymously characterize their data on the species they study, and 3: Logistic regression analysis to help determine the functional relationship, or measure of association (risk) between anthropogenic ocean sound and impacts to cetaceans and fish.

Results indicate an increasing risk of disturbance behaviors in response to increasing anthropogenic sound levels, and that observed free-ranging populations (n >1486 animals) have lower behavioral thresholds to anthropogenic sound than observed captive individuals (n = 25 animals). Empirical estimates indicate a .945 probability that the sound threshold for free-ranging animals lies below the 180dB rms NMFS status quo criterion. Survey data suggests a significant increase in the concern over global ocean sound over the 10-year period - with 51% of criteria recommendations dropping from the 180dB rms status quo to 140dB p-p and below, representing more than a 50% shift toward the 100dB rms average ambient assumed in this study. It is concluded that these empiricists demonstrated a cooperative strategy which is in the early stages of adaptive management favoring integrating solutions to sustainability problems by way of collective management, and advocate precautionary behavior. Communications strategies are identified and discussed and recommendations include open data base collaborations.

This project thus demonstrates the utility of a transparent international data base instrument and suggests a broader strategy for greater scientific leadership in guiding policy toward achieving sustainable management of living marine resources.