Commercial harvests of saltwater crocodile Crocodylus porosus eggs by Indigenous people in northern Australia: lessons for long-term viability and management
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Published source details
Corey B., Webb G.J.W., Manolis S.C., Fordham A., Austin B.J., Fukuda Y., Nicholls D. & Saalfeld K. (2018) Commercial harvests of saltwater crocodile Crocodylus porosus eggs by Indigenous people in northern Australia: lessons for long-term viability and management. Oryx, 52, 697-708.
Published source details Corey B., Webb G.J.W., Manolis S.C., Fordham A., Austin B.J., Fukuda Y., Nicholls D. & Saalfeld K. (2018) Commercial harvests of saltwater crocodile Crocodylus porosus eggs by Indigenous people in northern Australia: lessons for long-term viability and management. Oryx, 52, 697-708.
Actions
This study is summarised as evidence for the following.
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Engage local communities in conservation activities Action Link |
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Relocate nests/eggs for artificial incubation: Crocodilians Action Link |
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Engage local communities in conservation activities
A replicated, before-and-after study in 1989–2015 in freshwater swamps and tidal river banks within four river systems in Northern Territory, Australia (Corey et al. 2018) found that once an Indigenous management company took over the harvest and incubation of saltwater crocodile Crocodylus porosus eggs, hatching success rates reduced by more than a third. Results were not statistically tested. When a saltwater crocodile egg harvesting programme was under Indigenous management, incubation success rates were reduced (654 hatchlings from 1,396 live eggs/year) compared when it was under external management (1,413 hatchlings from 1,659 live eggs/year). Egg collection rates were also lower under Indigenous management (Indigenous management: 1,416 eggs harvested/year; external management: 2,359 eggs harvested/year). Saltwater crocodile eggs were collected and incubated as part of a regional government-led sustainable harvest initiative. In 1989–1997 an external management company ran the programme. In 1998–2015 it was run by a local Indigenous management company. In 1996–1997 eggs were harvested by the external company and incubated by the Indigenous management company. There was no harvest in 2007–2008. Annual quotas were 2,700–3,000 eggs/year (total limit of 70,000 eggs/year across the territory). Eggs were incubated at a constant temperature of 32°C and ≥99% humidity. Local workers were paid based on the number of eggs collected and hatchlings produced.
(Summarised by: Katie Sainsbury)
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Relocate nests/eggs for artificial incubation: Crocodilians
A replicated, before-and-after study in 1989–2015 in hatching facilities within four river systems in Northern Territory, Australia (Corey et al. 2018) found that artificially incubated saltwater crocodile Crocodylus porosus eggs hatched in captivity, but hatching success rates differed between local and external management. Results were not statistically tested. Hatching success of saltwater crocodile eggs as part of a sustainable harvest programme was 49% when run by a local Indigenous community organisation (654 hatchlings from 1,396 live eggs/year) compared to 84% when it was run by an external management company (1,413 hatchlings from 1,659 live eggs/year). Saltwater crocodile eggs were collected and incubated as part of a regional government-led sustainable harvest initiative. In 1989–1997 an external management company ran the programme. In 1998–2015 it was run by a local Indigenous management company. In 1996–1997 eggs were harvested by the external company and incubated by the Indigenous management company. There was no harvest in 2007–2008. Annual quotas were 2,700–3,000 eggs/year (total limit of 70,000 eggs/year across the territory). Eggs were incubated at a constant temperature of 32°C and ≥99% humidity. Local workers were paid based on the number of eggs collected and hatchlings produced.
(Summarised by: Katie Sainsbury)
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