Population studies at Osprey
Reef
Andy Dunstan, Dean
Miller, Scott Herring, Emma Hutchison and Tracey Medway - Undersea Explorer, Port Douglas
Introduction:
-
Nautilus are
reef predators and scavengers
-
inhabit
depths of between 150m to 600m in the tropical, Indo Pacific region.
-
only
cephalopod with an external shell
-
extensive
500 m.y. Nautiloid fossil record
-
harvested
for shell collecting trade
UE research
progress
-
Successful
sampling of over 500 individuals
-
N. pompilius
only species found at Osprey to
date
-
7% recapture
rate
-
3700
individuals approximate population estimate
-
Mean maximum
diameter - 130.2 mm
-
Mix of
mature / immature animals - no juveniles
-
aquarium
induced ‘stress’ markings also naturally occurring
-
75% of
sample are males
Aims:
To describe:
-
taxonomy and
morphology of nautilus populations at Osprey Reef
-
movement
patterns
-
growth rates
-
population
size and structure
-
create a
quality educational program describing nautilus biology and research
Methods:
-
Capture by
deep set baffle traps - 250m
-
Long term
weekly sampling program
-
Mark -
Recapture of individuals
-
Size, sex and
maturity data records
-
Dissection to
confirm sex and maturity data - small subsample
