Marine Mammal Risk Mitigation using passive acoustic technologies

Passive acoustic technologies and associated algorithms that detect, classify and localize marine mammals are becoming the preferred means of performing scientific investigations in the marine mammal risk mitigation (MMRM) project at the NATO Undersea Research Centre. During the last nine years, this robust scientific program has investigated, among other aspects, the habitat and behavior of the primary species of concern, Cuvier´s beaked whales (Ziphius cavirostris). The SIRENA ´08 sea trial, conducted from 17 May to 18 June 2008 in the Alboran Sea, was the most recent sea trial in a series of such campaigns that supported the MMRM project. Operations aboard the NRV Alliance were divided into three phases; during phases 1 (19 - 27 May) and 2 (29 May - 6 June), line-transect surveys were performed using acoustic and visual methods to determine the presence and absence of cetaceans. During phase 3 (8 - 16 June), focal follow and tagging of Cuvier´s beaked whales and long-finned pilot whales (Globicephela melas) were performed. Glider operations and visual observations were also performed from a shore station during all three phases. Several non-acoustic tools and techniques were used, tested and evaluated during SIRENA ´08; however, this paper will focus on the passive acoustic technologies employed on the cruise.