Adapting dugong catching techniques to different cultural and environmental settings

Abstract

[Extract] The relationship between a species' distribution, habitat use, and the environment is fundamental in ecological research (MacArthur 1972, Guisan and Zimmermann 2000), particularly because understanding a species' spatial ecology and identifying the spatial scale that is biologically meaningful provides the necessary information for optimal management (Levin 1992, Dungan et al. 2002, Nams et al. 2006). Tracking using acoustic, VHF, satellite-linked telemetry, or archival tags (for examples see Mate 1995, Read and Westgate 1997, Hatase et al. 2002, Sheppard 2006) provides valuable information into a species' distribution, behavior, and habitat use (Stone et al. 1999, Cooke et al. 2004, Godley et al. 2008). However, tracking animals, especially cetaceans and sirenians that spend all of their lives in the water, can be difficult as there are numerous challenges associated with the tag deployment (Irvine 1982, Marsh and Rathbun 1990), in particular when animals need to be captured first. The dugong, Dugong dugon (Muller, 1976), is a sirenian that has to be caught prior to deployment of satellite transmitters (Marsh and Rathbun 1990). Unless they are in clear shallow water, dugongs can be difficult to capture (Marsh and Rathbun 1990, Lanyon et al. 2006, Holley 2006). Since the late 1980s, dugongs have mostly been caught using the standard method, first used by Marsh and Rathbun (1990) and described in detail by Lanyon et al. (2006). This method involves the researchers pursuing the dugong in a boat until the animal is fatigued. Then it is captured manually around the peduncle region by catchers jumping into the water. The rodeo technique was developed to catch dugongs in relatively shallow, coastal waters under good weather conditions (<10 knot winds), which allow the target animal to be followed as it swims under water.