Davies, 2000:

• Five tagging exercises have been completed over a period of 22 months from April 1992 to February 1994 on the cluster of reefs south of Innisfail (Beaver, Taylor, Farquharson, Little Potter (17 060 and 17 061) and Potter Reefs) in the Cairns Section of the Great Barrier Reef Marine Park which have been zoned for the Effects of Fishing Program Reef Experiment.
• A total of 4627 P. leopardus have been tagged and released on the five reefs with a total of 443 returns to date from the public (300) and the four tag-recovery exercises (143). Ninety-nine per cent of the research returns of P. leopardus were returned from their reef of release. One inter-reef movement was recorded from Taylor to Beaver Reef. The results of the research recovery exercises indicate movement of P. leopardus among reefs is negligible and unlikely to confound treatment effects in the proposed Effects of Line Fishing Experiment.
• Thirty-six per cent of the public returns were returned from reefs other than the one on which they were released. The majority of inter-reef movement from the public returns was from Beaver (Closed) to Taylor Reefs and from Potter Reef to other reefs in the cluster. On the basis of the public returns, frequency of inter-reef movement of P. leopardus varies significantly among reefs within the cluster and ranges from 12 per cent at Farquharson Reef to 40 per cent at Potter Reef.
• It is suggested that the disparity in the extent of inter-reef movement of P. leopardus from Beaver Reef between the public and research returns is largely due to infringements, rather than a high level of movement from Beaver Reef. If this is the case, it is suggested that the level of fishing effort on Beaver Reef, in the form of infrequent pulse-fishing, may be enough to negate the potential effects of protection from fishing (i.e. higher abundance and protection of larger size classes of major target species). The catch per unit effort (CPUE) and length frequency data for P. leopardus tend to support this.
• Such a level of infringement on reefs zoned Marine Park ‘B,’ which are theoretically closed to fishing, questions the validity of using these reefs as ‘unfished’ or ‘control’ treatments for large-scale manipulative experiments designed to investigate the effects of fishing, as the treatment effect size is likely to be small.
• Infringements do not explain the difference between estimates of inter-reef movement from research and public returns for the other reefs, and Potter Reef in particular. Furthermore, the research returns demonstrated a significant level of movement of P. leopardus among blocks within reefs which may represent movement of P. leopardus to spawning aggregations. Consequently, it is recommended that the movement study be continued as an integral part of the proposed manipulative experiment in order to: i) resolve the disparity between the estimates of inter-reef movement from the public and research returns, and ii) quantify the effect of a known change in abundance on the patterns of movement of P. leopardus.

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Citation and/or URL

Davies, C.R. 2000, Inter-reef movement of the common coral trout, Plectropomus leopardus. Research Publication 61, Great Barrier Reef Marine Park Authority, Townsville, Australia  

Spatial Coverage

Reefs off Innisfail and Cairns 

Temporal Coverage

1992

Update Frequency

Not applicable 

Other Information

None