World Status, Exploitation and Trade - WIDECAST

AUSTRALIAmore turtles than they needed and then to release those that they did notwant (Limpus and Fleay, 1983).Kowarsky (1982) found that most of the turtle hunting was conducted duringthe mid-summer months on Yorke Island, but a detailed analysis byNietschmann (1984) in the west of the region found no seasonality inlandings.Nietschmann (1984) reported that each turtle caught by Torres Strait Islandcommunities involved a mean round-trip of 22.9 km and a total time of 1 hr56 min. There are some indications that hunters have recently had to travelfurther to maintain their catch levels (Limpus and Fleay, 1983). Turtlesare generally scarce around human settlements, and those that are presentare usually small. This localised depletion has been attributed toselective hunting for large turtles (-Limpus and Parmenter, 1986). Limpusand Parmenter (1986) concluded that there was a strong probability that theutilisation represented overharvest of the Torres Strait turtle populations,though it is not clear whether they referred only to the local harvest orwhether the harvest of migrating turtles in other areas was to blame.Opinions differ as to the significance of the egg harvest. Kowarsky (1982)reported that several of the respondents to his questionnaire survey claimedto collect fewer than 20 eggs a week, while two respondents gave estimatesof about 1000 a week. There is no indication of which areas these reportsrefer to, but Limpus and Parmenter (1986) found that in the eastern TorresStrait almost every egg laid by E. imbricata was harvested on the inhabitedislands, and many were also harvested on some of the uninhabited islands.Human egg predation was thought to be less severe in the west of the Strait,but there predation by varanid lizards was very heavy.Hunting methods Host hunting is now carried out by harpoon fromaluminium dinghies, powered by outboard motors, although dugout canoes wereformerly used. Occasionally turtles are caught by hand in reef pools(Kowarsky, 1982).Historical trends There is no direct evidence of the previous levels ofhunting in the region, and inferences can only be made from what is known ofthe human demographic trends. The population of mainland Aboriginals hasdeclined dramatically since the time of white settlement, from a total of300 000 for the whole country to about 40 000 in 1965. The Torres StraitIsland communities do not appear to have suffered a similar decline, thepopulation being estimated to be 3000-4000 in the 19th century and to fallto slightly under 3000 by the end of the 20th century (Kowarsky, 1982).Improved hunting facilities, in the form of motor boats, nylon rope, steelharpoons, etc., have resulted in increased hunting pressure (Limpus andFleay, 1983), but Kowarsky (1982) considered that these improvements mayhave been offset to a certain extent by the high cost of boats and fuel foroutboard motors. A recent trend for Aboriginals to move back to theirtraditional clan territories and away from the main settlements may increasethe reliance on turtles in the future. Kowarsky (1982) concluded that "itwould be reasonable to presume that the hunting pressures in the past wereat least as great, if not greater, than those existing today". There areverbal reports that the turtle population on Bramble Cay has declined overthe last 30 years, and this is thought to be attributable to harvest byPapuan boats (Limpus and Parmenter, 1986). Parsons (1972) indicated thatthere was formerly ("half a century ago") a large fishery for E. imbricatain the Torres Strait which produced nearly 5000 lb (2273 kg) a year.76