size: 5036KB - Crocodile Specialist Group

lil
Kilimmjaro/Tanga Region
Pa gani River
This is a very sinuous river with an extensive tree and reed overhang. There are very few
sandbanks and the river can be divided into two strata. The upstream section flows through an
extensive floodplain which was still holding water. Crocodile density was estimated at 0.17
crocodiles/km. The downstream section is similar to the upstream section but there are no
swamp areas. Density was estimated to be 0.02 crocodiles/km-
Lake l\Yumbo ya Mungu
This is a new lake which, like Lake Mtera, is heavily settled with fishermen. No crocodiles
were seen,
OBSERVER CORRECTION FACTORS
On one occasion it was possible to ctrry out a tanden count which allows some estimation of
observer error. The correction fictor for observer 1 (Games) was estinated to be 1.8 and for
observer 2 (Liyimo) it was estimated to be 4.2. This means that any sightings by those
observershould be multiplied by these corfection fhctors if the aim is to speculate ahout a
possible total population estimate.
SPOTLIGHT COUNTS AND CORRECTION FACTORS
Night counts were carried out in the Kilombero and Rutjji rivers and in Lake Tagalalla (Tables
4- 5 and 6).
In the Bomalangarea ofthe Kilombero river both banks were counted tbr 6 km. This channel
was surveyed tiom the air two weeks later. The night count showed 132 crocodiles while the
aerial survey located 4l crocodiles. This ireans that dle correction faotor is 3.22. It is doubtful
that this can be extrapolated to the enti.e length of dte Kilombero as much of the channel
flowing towards Shiguli talls is very difierenl in chffacter (the Bomalangarca is a myriad of
channels flowing through reeded sandbanks while the rest of the river flows down a single
channel contained within steep mud-banks). This section is probably more similar to sections
of the lower Rufiji.
Two sections of the lower Rutiji were surveyed tbr crocodiles at night. ln a 12 km stretch of
the river from the Kidai ferry to opposite Lake Tagalalla 304 crocodile.! were connted. During
this survey only the northern bank was surveyed. It was estimated from 1:50000 (1966) maps
that lhere were 32 km of shoreline between these two points. A correction of 2.6 woukl yield
an estimate of 790 crocodiles. A total ol 195 c.ocodiles were countecl fiom the air in this
section which would indicate a correction tac()r fir the aerial count of4.l. A similar corfection
is calculated for the section of river fiom Rutlji river camp (reserve boundary) to Lake
Nzerakera. The night count (both banks) revealed 168 crocodiles while 39 animals were
counted tiom the air giving a correction f'actor of 4.3.
The entire shoreline of Lake Tagalalla was su.veyed at night and 816 crocodiles were counted.
An aerial survey sbowed 181 animals which is a correction factor of 4.5-