Putting marine sanctuaries into context: a comparison of estuary fish assemblages over multiple levels of protection and modification

1. In recent decades there has been a significant effort to establish marine sanctuaries for the purpose of protecting marine biodiversity and ecological processes. While many studies have demonstrated that marine sanctuaries increase the abundance, diversity, and trophic level of marine fish communities, few have compared these parameters across multiple levels of protection and human modification. 2. This study utilized baited remote underwater video to compare fish assemblages between marine parks, between different levels of protection within parks (sanctuary and habitat protection zones), and between parks and highly modified systems with similar ecological communities. 3. It was demonstrated that sanctuary zones have higher abundance of targeted fish species compared with other areas within some marine parks. 4. The total abundance of targeted species and abundances of some key fisheries species (e.g. pink snapper) were found to be higher in sanctuary zones. This suggests that increased protection may be effective at improving these aspects of the fish assemblage. 5. However, when marine parks were compared with highly modified environments it was found that targeted species were much more abundant in the highly modified systems. 6. Community composition of entire fish assemblages also differed between these levels of modification and economically important fisheries species contributed most to this difference. 7. These findings suggest that while highly protected sanctuary zones may increase the abundance of targeted fish compared with less protected areas within the same estuary, highly industrialized or urbanized systems, not typically chosen as marine parks, may actually support more targeted species of fish. 8. It was demonstrated that forms of modification in addition to fishing pressure are having large effects on fish assemblages and productivity. Copyright # 2011 John Wiley & Sons, Ltd. Received 31March 2011; Revised 28 July 2011; Accepted 14 August 2011