The influence of an offshore artificial reef on the abundance of fish in the surrounding pelagic environment

Artificial reefs are a popular fisheriesmanagement tool, but the effect of these reefs on the abundance of fish in the surrounding pelagic environment is uncertain. Pelagic baited remote underwater video (PBRUV) was used to observe the fish assemblage surrounding an offshore artificial reef (OAR), near Sydney,Australia. PBRUVswere deployed at three distances (30, 100, 500m) from the OAR, and compared with a drop camera deployed directly over the OAR. There was a significantly greater abundance of fish on the OAR, but no significant difference in abundance at the 30-, 100or 500-m distances. Two highly mobile non-resident species (Seriola lalandi, Pseudocaranx dentex) were significantly more abundant on the OAR, but this association was not detected 30m away. The lack of a significant difference in total fish abundance, or in assemblage composition, between the 30-, 100and 500-m distances suggests that any association with the OAR is on a localised scale (,30m). One exception was the ocean leatherjacket (Nelusetta ayraudi), which had an association detected 100 m from the OAR. This predominantly small-scale effect may be influenced by the proximity of this OAR to numerous natural reefs. Additional keywords: BRUV, MaxN, pelagic fish, PERMANOVA, Trachurus. Received 22 August 2013, accepted 29 July 2014, published online 6 January 2015