Management program for the saltwater crocodile in the Northern Territory of Australia 2009-2013
Fukuda, Yusuke; Delaney, Robyn; Leach, Gregory J
Northern Territory. Department of Natural Resources, Environment, The Arts and Sport
E-Publications; E-Books; PublicationNT
The draft program is open for public comment to Friday 29 May 2009. Includes Summary document.
Date:2009-04; Made available via the Publications (Legal Deposit) Act 2004 (NT).
Crocodylus porosus -- Northern Territory; Crocodiles -- Conservation -- Northern Territory; Crocodiles -- Control -- Northern Territory; Crocodiles -- Government Policy -- Northern Territory
Northern Territory Government
60 pages : illustration, maps ; 30 cm.
Attribution International 4.0 (CC BY 4.0)
Northern Territory Government
Draft Management Program for the Saltwater Crocodile in the Northern Territory 14 4. To remove particularly large or iconic crocodiles (greater than 4.2m). Any removal will be regulated closely to ensure the presence of large iconic animals which are important for cultural and social reasons and to the tourist industry. 5. From sites where crocodiles are particularly significant to local Indigenous people. Performance Indicator Ensure all harvest permits minimise the possible negative impact on or conflict with tourism or cultural interests. Harvest ceiling The ceilings covering both eggs and live animals that have developed through previous management programs was never based on any biological parameters but were always a ceiling set well above what was anticipated to be collected and that was still considered sustainable. The use of egg numbers as the basic harvest measurement has remained unchanged and will continue in this program. The harvest ceiling, permits and egg allocation will be based on live eggs (see definitions). This change addresses concerns from both industry and regulators. A practical compliance measure at an early stage in the harvest/farming process is now the measure of eggs placed into the incubator. Royalties to the Northern Territory Government will continue to be based on viable eggs. An overarching harvest ceiling will be set for the whole of the Northern Territory. This ceiling will continue to be developed very much in an adaptive management sense. The natural mortality of eggs in the wild is very high and can approach 100%. Studies of the mortality of crocodiles at each stage of their life cycle indicate that the survival of hatchling, juvenile and adult crocodiles is most probably dependent on the density of larger crocodiles that prey upon and competitively exclude smaller crocodiles (Webb and Manolis 1993). Because the survival of crocodiles is a function of crocodile density it is unlikely that the harvesting of crocodile eggs at current rates will substantially affect the size or age structure of the population (Appendix 3). The current population size and structure indicates that a very low percentage of eggs/hatchlings will be surviving to later age classes and this will be reflected in the predicted inability to detect any harvest impact on the population. Despite an increasing egg harvest, the Northern Territory population has continued to increase in both numbers and in biomass (Figure 1, Appendix 3). This trend is entirely consistent with our understanding of the population dynamics of Saltwater Crocodiles and supports continuing with an adaptively managed increase in the egg harvest. The ultimate test of whether a particular level of egg harvest will prove to be detrimental in the long-term can only be determined by implementing such a harvest and then determining whether the total wild population increased, decreased or remained stable despite the harvest. Recent levels of egg harvest have been approaching 40,000 eggs. It is proposed to commence this program with an increased ceiling of 50,000 live eggs for at least the first two years of the program. This increase in egg harvest is further offset by reducing the harvest of each of the juvenile and adult size classes by 100 individuals. The total number of C. porosus that can be taken for commercial harvest within the Northern Territory in a year or for eggs during a nesting season, within this program is shown in Table 3. There is no requirement for the Northern Territory Government to allow the full ceiling to be taken in any year.