Report of the Second Workshop on The Biology and Conservation of ...

The Status <strong>of</strong> Marine Mammals in <strong>the</strong> Coastal Waters <strong>of</strong> Nor<strong>the</strong>rn AustraliaMarsh, Helene; Parravergara, GuidoSchool <strong>of</strong> Tropical Environment Studies and Geography, James Cook University, Townsville, Qld 4811,AustraliaAustralian waters in Sou<strong>the</strong>ast Asia extend from Northwest Cape in <strong>the</strong> west to <strong>the</strong> tip <strong>of</strong> Cape YorkPeninsula in <strong>the</strong> east, including Torres Strait. The region is remote and sparsely populated by smallindigenous communities and isolated nodes <strong>of</strong> industrial development, usually associated withland-based mining and/or <strong>of</strong>fshore oil and gas. Eleven species <strong>of</strong> cetacean have been confirmedfrom anecdotal reports <strong>of</strong> stranded animals, by-catch and/or sightings: humpback whale, roughtoo<strong>the</strong>ddolphin; Indo-Pacific humpbacked dolphin, bottlenose dolphin, spinner dolphin, stripeddolphin, common dolphin, false killer whale, short-finned pilot whale, Irrawaddy dolphin, andgoose-beaked whale. Cetaceans in <strong>the</strong> region <strong>of</strong> North-west Cape have been surveyed, promptedby concern about <strong>the</strong> impact <strong>of</strong> seismic surveys on migrating hump-back whales. Dolphins havealso been recorded during aerial surveys for <strong>the</strong> dugong, <strong>the</strong> most abundant marine mammalin coastal waters. Since 1996, aerial surveys for dugongs have been conducted between North-West Cape and <strong>the</strong> De Grey River in Western Australia (population estimate 2046+ se 376), <strong>the</strong>Queensland coast <strong>of</strong> <strong>the</strong> Gulf <strong>of</strong> Carpentaria (4266 + se 657) and in Torres Strait (27881 + se 3216in 1996; 14106 + se 2314 in 2001). The confounding effects <strong>of</strong> large-scale dugong movementsapparently associated with seagrass diebacks make <strong>the</strong> differences between surveys difficultto interpret. The largest source <strong>of</strong> dugong mortality is traditional hunting, especially in TorresStrait where hunting rights are protected by international treaty between Australia and PapuaNew Guinea. Hunting is generally restricted to areas close to Indigenous communities. Theinshore dolphins and <strong>the</strong> dugong are subjected to incidental take in gill net fisheries. There arefew conservation measures specifically directed at marine mammals, apart from isolated spatialclosures to protect dugongs from gillnet by-catch. An endangered species awareness course hasbeen developed for gillnetters in Queensland and information on measures to reduce marinemammal bycatch is supplied to fishers in <strong>the</strong> Nor<strong>the</strong>rn Territory.<strong>Second</strong> <strong>Workshop</strong> on <strong>the</strong> Biology and Conservation <strong>of</strong> Small Cetaceans and Dugongs <strong>of</strong> SE Asia 147