STUDENT > TERTIARY > CONSERVATION & RESEARCH PROGRAM
Student Education Experiences
Impact of Cane Toads on Freshwater Crocodiles and other
wildlife in the McKinlay River, Northern Territory.
The endemic Australian Freshwater Crocodile (Crocodylus
johnstoni) is widely distributed across Northern
Australia, inhabiting freshwater rivers, creeks and pools,
mainly upstream of tidal influence. Research by Professor
Grahame Webb and his team in the late 1970s and early 1980s
took the "freshie" from one of the least known crocodilians to
one of the best-known. The cornerstone of this program was the
capture and marking of a large proportion of the McKinlay
River population of Freshwater Crocodiles (about 2000
With the spread of the Cane Toad (Bufo marinus) into
the Northern Territory, this population is now threatened.
Toads are poisonous, and if eaten can cause death. Freshwater
Crocodiles in other rivers colonised by toads are known to
have been affected.
By catching crocodiles before and after Cane Toad
colonisation, the project aims to quantify natural survival
rates, and to measure the impact of Cane Toads. Quantifying
survival rates will greatly improve our understanding of the
population dynamics of Freshwater Crocodiles.
Catching begins in late August, after the nesting season is
finished. Crocodiles are caught using fine mesh fishing nets,
which are strung across the billabongs in which the animals
congregate during the dry season. All crocodiles caught are
sexed, measured, and if unmarked, are scute-clipped for future
The impact of Cane Toads on other wildlife, specifically
varanid lizards and fish, is also being measured.
To date over 1,200 Freshwater Crocodiles have been captured
in 2001 and 2002. Analysis of the data has now begun. Further
catches to assess the impact of Cane Toads are planned for
2003 and beyond.
Participation is on a formal (ie. through an educational
organisation) and informal (ie. individual) basis.
Duration: August to
October (2001 - 2003 and possibly later).
Cost per Participant:
Free, and food is provided during
fieldwork. Participants are expected to support themselves at
all other times.
Establishment of the original database is the result of a
decade of work by a number of researchers and it is difficult
to place a value on it. The current project's costs are based
on staff time, vehicles, equipment and the difficult to assess
value of staff expertise.
How the Experience is Marketed:
Internet and word of mouth.
full-time staff member, with additional staff support when
Links & Partners:
Northern Territory University, Green Corps, Australian Army.
project is still underway. The first two years of field work
have been very successful with almost 1,300 crocodiles
captured. A significant number were recaptures of crocodiles
originally marked between 1978 and 1989.
Chief Scientist, Charlie Manolis firstname.lastname@example.org
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