Cheap DECAF: Density Estimation for Cetaceans From Acoustic Fixed Sensors Using Separate, Non-Linked Devices

• Main Authors: Thomas, Len, Matias, Luis, Mellinger, David K
• Other Authors: OREGON STATE UNIV NEWPORT HATFIELD MARINE SCIENCE CENTER
• Format: Text
• Language: English
• Published: 2013
• Subjects: Biological Oceanography; Acoustic Detection and Detectors; *ACOUSTIC DETECTORS; *CETACEA; DENSITY; DEPTH; ESTIMATES; FREQUENCY BANDS; TRACKING; UNCERTAINTY; CUE-COUNTING METHODS; *DECAF(DENSITY ESTIMATION FOR CETACEANS FROM ACOUSTIC FIXED SENSORS); SOUND ENERGY; SPATIAL DENSITY; Balaenoptera physalus
• Online Access: http://www.dtic.mil/docs/citations/ADA602567; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA602567

Several of the current methods for density estimation of cetaceans using passive fixed acoustics rely on large, dense arrays of cabled hydrophones and/or auxiliary information from animal tagging projects conducted at the same time as the acoustic survey. Obtaining such data is costly, and may be impractical to the wider community interested in estimating cetacean density. Therefore, the goal of Cheap DECAF is to focus on the development of cetacean density estimation methods using sensors that are sparsely distributed and less expensive to deploy than the cabled military arrays focussed on to date. Recordings of fin whales (Balaenoptera physalus) from a sparse array of Ocean Bottom Seismometers (OBSs) are being used to develop and test a variety of density estimation methods. The OBS array was deployed for 1 year (2007-2008) off the south coast of Portugal, near the Straits of Gibraltar (Fig. 1). The specific objectives of the project are to: 1. demonstrate how cue-counting methods can be used efficiently to obtain estimates of density over long time periods and large spatial scales using directional sound sensors; 2. extend the methods to allow for uncertainty in the depth of vocalizing animals; 3. develop and apply methods based on tracking moving individual animals; 4. develop and apply methods based on measuring total sound energy in relevant frequency bands; 5. obtain baseline estimates of spatial density of fin whales in the study area. Prepared in collaboration with the University of St. Andrews, St. Andrews, UK, and Centro de Geof sica, Universidade de Lisboa, Lisbon, Portugal.