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Coral Trout Reproductive
Behaviour
  
Twelve coral trout (Plectropomus leopardus)
were caught by precision angling on the Great Barrier Reef in Queensland,
Australia, and were implanted with depth sensitive acoustic transmitters. The
fish were then released at the spawning aggregation site where they
originated from, and were tracked with sub-meter resolution using Radio-linked
Acoustic Positioning (RAP). Movements and behaviour, during and after spawning,
were recorded between November 2001 and February 2002, using RAP array
technology and mobile
tracking by watercraft and SCUBA. Data were interpreted and described using
the Biotrek telemetry visualization and analysis package.
These images are screen shots of coral trout behaviour from our proprietary
Sonic Telemetry Data Analysis program BIOTREK:
Preliminary results:
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Individual
spawning
events coded in data (surface rushes identifiable with 3D RAP data) –
timing, duration, frequency, and periodicity all available in data set
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habitat
polygons had preferences developed for spawning and post-spawn period
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some
fish
moved < 1 km away from spawning aggregation sites after the normal
spawning period
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intraspecific
interactions among males indicate physical confrontation, including some
visual evidence of oral-genital attacks, with some males having mutilated
genitalia
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translocations
– 4 fish recaptured by angling (recap rate = 40%), one fish
recaptured twice (cf. 2000
tagged from 1985-2001 with a 7 % recapture rate (Austag 2001))
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l4
fish translocated within lagoon distances from 700 m to 3.5 km, 3 returned
to aggregation site within 2 d (sometimes within 3-4h)
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l1
fish moved across reef crest during dusk – approximately 800m to aggregation site. This
fish returned to spawning aggregation site within 0.5 h of displacement
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overall results suggest coral trout have strong
multi-site fidelity, and
exceptional homing ability in highly complex reef habitat that warrants
further research
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