Ecological traps in the marine environment: downsides to artificial reef deployment

Humans are altering coastal ecosystems at an unprecedented rate. One such change is the proliferation of artificial reefs (ARs), which have become a common management tool for stock enhancement of recreational fisheries and ... [ view full abstract ]

Humans are altering coastal ecosystems at an unprecedented rate. One such change is the proliferation of artificial reefs (ARs), which have become a common management tool for stock enhancement of recreational fisheries and habitat restoration. The benefits of ARs, however, depend on their suitability as habitat for marine species. ARs could result in the provision of seemingly suitable habitat that provides lower fitness advantages. If animals preferentially colonize such structures, this could result in an ecological trap. Here we investigate whether ARs can act as ecological traps for fish populations, through fish community and habitat quality comparisons between a common artificial reef type (Reef Balls) and adjacent natural reefs at three study locations in Port Phillip Bay, Victoria. We use quantitative assessment of fish recruitment, mortality rates, and fitness measures to establish whether ARs can act as ecological traps for several fish species. We found natural reefs displayed higher recruitment, abundance and survival for several fish species in comparison to the Reef Balls, indicating the artificial reefs likely do not effectively mimic the complexity of natural reefs. However, these results were dependent on whether adjacent natural reef was of a particularly good quality or a low laying, low complexity boulder reef. These results provide evidence that deployment of artificial reefs may not be effective management tools as they can act as ecological traps for some fish species in certain environments.. Understanding the effects of anthropogenic habitat modifications on marine ecosystems is vital for developing successful conservation and management strategies.