Designing Cost‐Effective Artificial Reefs: Fine‐Scale Movement and Habitat Use of Red Snapper around a Nearshore Artificial Reef Complex

Abstract

Artificial reefs are commonly used to provide structured habitat in areas with limited natural habitat to enhance the environment. Creating artificial reefs is expensive, and materials are often limited; thus, discussions are needed regarding the best material and design to maximize reefing efficiency while best meeting the goal of reefing programs. We tracked Red Snapper Lutjanus campechanus, an economically important and reef-dependent species, by using a Vemco Positioning System to determine fine-scale movements and habitat use around a nearshore reef comprised of three types of reefing structure: concrete reef pyramids, concrete culverts, and a sunken ship. Habitat use (core volume and home range, or the probability of a fish being absent 50% or 5% of the time, respectively) was significantly different by month, with the largest movements during summer months. Mean depth values also differed by study month (February-August), with Red Snapper residing deepest in the water column during August and shallowest during April. In the summer months, differences among structure types were observed in core volume use but not home range, suggesting that Red Snapper used similar-sized areas on all three structure types. A high reported recapture rate (77%; 10 of 13 fish) indicated that these easily accessible nearshore reefs undergo heavy fishing pressure. Half of the recaptures were reported as recaptured on a structure other than their tagging structure; however, tagged fish spent the greatest percentage of time on their tagging structure. Red Snapper habitat use was influenced more by the presence of structure than by the type of reefing structure. Using the results from this study combined with a cost comparison of reef types, we argue that use of the least expensive reefing material that covers the largest area may be the best policy in designing future artificial reefs.

Artificial structure selection by economically important reef fishes at North Carolina artificial reefs

“…Gag and red snapper on the other hand more frequently moved through the sandy bottom, but their movements were highly directed between structures; any observed off structure movements were straight-line movements suggesting that they are only displaying transient behavior over sand. Similar behavior has been observed in red snapper at an artificial reef in Texas where individuals displayed significant differences in habitat use between structures and open sand, using the structures more (Gibson Banks et al, 2021). Lastly, greater amberjack and almaco jack displayed large, circular movements over sandy bottom and frequently moved off structures.…”

“…However, our observed selection in red snapper could also be an artifact of where they were tagged; seven of our nine snapper were tagged at the vessel where the probability of remaining at the vessel during 1-hour intervals was 0.96 despite some individuals displaying a clear ability to move among structures. Red snapper monitored with a fine-scale positioning system at an artificial site in the Gulf of Mexico were also determined to select vessels over concrete structures like culverts and pyramids, but they too were observed spending the greatest amount of time on their tagging structure compared to other structures (Gibson Banks et al, 2021).…”

Artificial reefs through additive manufacturing: a review of their design, purposes and fabrication process for marine restoration and management

“…The efficiency of ARs depends on several critical factors highlighted in various studies. These factors include the importance of design management and reef complexity (Baine, 2001), targeting species and habitats for cost-effective ARs (Gibson Banks et al , 2021) and understanding the hydrodynamic, morphological and ecological behaviour of ARs (Cardenas Rojas et al , 2021). Performance criteria for developing these structures should include detailed information of the target species like population abundance, size structure and the reef-dependent biota; and detailed information of the habitat, such as larval recruitment, immigration, growth, reproduction, mortality and emigration (Carr and Hixon, 1997).…”