GBR - Fish communities of the Great Barrier Reef (AIMS LTMP)

The purpose of this study is to detect and quantify spatial and temporal changes in reef fish assemblages of the Great Barrier Reef (GBR). Between 1993 and 2005, reef fish assemblages of 46 reefs were monitored annually along permanent transects within a standard habitat using visual census. The selected intensive survey reefs are distributed across three positions of the continental shelf and among six sectors each representing one band of latitude. These reefs continue to be surveyed in odd years as part of the Long Term Monitoring Program (LTMP). The survey pattern changed in 2006 in response to the implementation of a new zoning plan for the GBR Marine Park in 2004. In order to assess the effects of re-zoning on the biodiversity of reefs, a different selection of reefs are surveyed in even years as part of the Representative Areas Program (RAP). Surveys are carried out for 28 pairs of reefs, with each pair comprising one reef  which was re-zoned as a no-take area in 2004 and another nearby reef which remained open to fishing. The RAP survey reef pairs are distributed among four of the same sectors in the original LTMP survey design and two different sectors. The cross-shelf distribution of reefs differs, though, as inshore reefs were not included in the RAP sampling design.

Fishes of 214 species are counted along the permanently marked transects. Larger mobile fishes (141 spp.) are counted in a 5m wide belt and damselfishes (73 spp.) are counted in a 1m wide belt. Total lengths of any coral trout species (Serranidae, Plectropomus spp.) recorded within transect belts have been estimated from 1996 onwards. Length estimates of other species within the Serranidae, Lethrinidae and Lutjanidae families have been recorded in RAP surveys since 2006.

To demonstrate spatial variation in fish community assemblages of the GBR, spatial distributions of a number of relevant variables have been mapped in Google Earth using the long term average. Monitoring data collected up until and including the 2008 field season are included. Spatial variation in species richness and in total fish abundance are displayed. Fish species have also been divided into trophic groups and the spatial variation in abundance of each group is mapped accordingly.