Biogeographic Patterns of Reef Fish Communities in the Saudi Arabian Red Sea

Abstract

As a region renowned for high biodiversity, endemism and extreme temperature and salinity levels, the Red Sea is of high ecological interest. Despite this, there is relatively little literature on basic broad scale characteristics of the biodiversity or overall reef fish communities and how they change across latitude. We conducted visual transects recording the abundance of over 200 species of fish from 45 reefs spanning over 1000 km of Saudi Arabian coastline and used hierarchical cluster analysis to find that for combined depths from 0m-10m across this geographical range, the reef fish communities are relatively similar. However we find some interesting patterns both at the community level across depth and latitude as well as in endemic community distributions. We find that the communities, much like the environmental factors, shift gradually along latitude but do not show distinct clusters within the range we surveyed (from Al-Wajh in the north to the Farasan Banks in the south). Numbers of endemic species tend to be higher in the Thuwal region and further south. This type of baseline data on reef fish distribution and possible factors that may influence their ranges in the Red Sea are critical for future scientific studies as well as effective monitoring and in the face of the persistent anthropogenic influences such as coastal development, overfishing and climate change.