size: 5036KB - Crocodile Specialist Group

103
Table 2. The ratio of first sightings of a tag to subsequent sightings of a tag, for one month
period since release.
lst
Month
2r\d
Month
3rd
Month
First Sighting 26 9 l
4th
Month
Repear Sighting l0 17 18 l6
Such a decline through time would be exp€cted as the number of fiIst sightings approaches
the total number released. In this case there are still more than 60 taga that have not yet
been seen. Tag loss is assumed to affect previously seen and unseen tags equally.
These preliminary results indicate the possibility of considerable mortality _ affecting up to
half of the animals released. Another factor that suggests that mortality is considenble is
that only 3 of the 54 animals released in the study area in January 1991 have be€n found
during this study, and one of those is known to have died since.
1.2) Radio telemetry results
Twenty five animals carrying ndio tags werc released in April 1992. In the thrce months
since release there has been unexpectedly high rnortality (Figure 2).
Five histories of relocation ended with the corlar being shed and these are not considered
further. Of the 20 .
rcmaining, only 8 are currently known to be alive, while 6 are definitely
dead and contact has been lost with the rcmaining 6, in circumstances which suggest they are
also dead.
E Alive
/
,/ /4
2s _ s = 20\-6
Deadl,
cRoc
\
\6
suspect dead
2 TnJMAN
Figure 2. The present status of released radio tagged
juvenile crocodiles in the cachegachestuary.