There is considerable concern about the effects of fishing on the GBR. Two types of fishing may have substantial effects over large areas: (1) "line" fishing (recreational and commercial) for larger species such
as coral trout, and (2) commercial "trawl" fishing for prawns and scallops in inter-reef areas and in the GBR lagoon inshore of the midshelf reef complex. Besides directly affecting the abundance of target
species, line fishing may have a variety of indirect effects by altering the trophic structure (predator-prey interactions, competition) of reef communities. Trawling may affect benthic communities used by reef
species for functions such as feeding, dispersal, and juvenile rearing. There may be important "interaction effects" between line and trawl fishing, particularly if trawling affects dispersal of fish among reefs
and hence the immigration component of recruitment to reef populations subject to line fishing (ie, line fishing effects may be larger in areas where trawling is present, due to reduced replenishment of heavily fished reef populations by dispersal from areas where less fishing occurs)
