Fishing effort in the far northern section cross shelf closure area of the Great Barrier Reef Marine Park: the effectiveness of area-closures

A meta-analysis of available information on the intensity and distribution of illegal prawn (shrimp) trawling is reported from a 10 000 square kilometre cross shelf area-closure in the tropical Great Barrier Reef Marine Park. Northern and southern borders of the closure were subject to edge effects as trawlers over-ran their hauls, legally started in the adjacent open zones. There was considerable illegal trawling inshore along a north-south navigation channel running through the area-closure. The middle and outer regions of the closure were originally denied to trawlers because of 'rough ground' but this is probably no longer the case since the general adoption of advanced navigation aids (GPS). The area least likely to have been heavily trawled is the central mid-shelf section of the closure in a region of uncharted shoal reefs. Many trawlers fish in the accessible sections of the closure on a casual or incidental basis but approximately 47 boats do so on a consistent basis. An estimated yearly fetal of 3260 days illegal trawling occurs, giving an approximate estimate of 69 days illegal trawling per regular offender: The implications of this level of noncompliance are the probable invalidation of the original objectives of conservation and maintenance of a pristine reference area in all but the central section of the closure. Management of marine world heritage areas requires the acknowledgement that the harvesting of fish, prawns and other living resources may be an established use of the Marine Park but it also requires a combination of education plus the adoption of effective monitoring technology, such as satellite vessel monitoring systems, to stop or at least reduce unauthorized fishing. (C) 1998 Academic Press Limited.