Impact of artificial reef deployment on reef fish movement and community assemblages

Artificial reefs provide critical habitat for fish in areas lacking
benthic structure, yet our understanding of how artificial reefs function
and develop is limited. Here, changes in fish community assemblages were
monitored using baited remote underwater video (BRUV) surveys before and
after a new artificial reef was deployed in the northern Gulf of Mexico.
Movement of red snapper (Lutjanus campechanus) and gray snapper (Lutjanus
griseus) between nearby oil and gas platforms (n=3) and the new artificial
reef was examined using acoustic telemetry, and residency was calculated
for fish associated with both structure types. Fish community development
at the artificial reef site was slow despite close proximity to existing
habitat, and fish communities at the artificial reef site did not differ
from control sites (unconsolidated substrate) one year after reef
deployment. Residency of red snapper and gray snapper at the artificial
reef was surprisingly low with most tagged fish emigrating rapidly, and no
tagged fishes from the surrounding platforms were detected moving to the
artificial reef during the initial eight months following artificial reef
deployment. While residency was much higher at the platforms, a major
hurricane (Hurricane Ida) passed directly over the sites and led to large
numbers of tagged fishes emigrating from the study area. Results highlight
an artificial reef with limited fish community development and low
residency after one year despite close proximity to existing habitats.
Given the presence of seasonal benthic hypoxia in this region, findings
suggest that artificial reefs with limited vertical relief may offer
sub-optimal habitat for reef fish in comparison to the substantial
vertical relief offered by standing platforms, reducing the potential
benefits to reef fish. Given the rapid decommissioning of oil and gas
infrastructure in the Gulf of Mexico, this study has significant
implications for rigs-to-reefs programs as well as artificial reef siting
and design.