Sabin Point Artifical Reef

On October 27th 2019, Rhode Island Department of Environmental Management (RIDEM) and The Nature Conservancy of Rhode Island (TNC) constructed an artificial reef off Sabin Point Park. The patch reef system was built using pallet-sized Reef Balls™ and has been providing habitat for recreationally significant fish for over a year now.

Research on Reef Balls™ suggests they create a more robust benthic habitat, ultimately attracting more fish to the reef. Artificial reefs also provide shelter and food resources for sub-legal size sportfish promoting both the growth and survival of these individuals (Powers 2003, Caddy 2011). Staff from RIDEM and TNC have sampled the site 12 times with fish pots and dove the reef 5 times since the reefs were created. The dive monitoring consists of collecting photo and video documentation of the reefs, removing fishing gear when necessary, and performing a holistic fish habitat monitoring assessment that investigates the colonization and productivity associated with the Reef Ball™ modules. Back in November of 2019, RIDEM and TNC divers visited the reefs just two weeks after the construction to capture information on the first colonizers. On this dive, much of the concrete material used to create the Sabin Point artificial reef was still exposed but each module amassed a small army of mud snails and a few blue mussel recruits.

During the 2020–2021 field seasons, RIDEM and TNC staff conducted the first series of post-enhancement surveys of the Sabin Point artificial reef. These surveys were conducted via SCUBA every two months to monitor seasonal shifts in succession that occur during the first-year post deployment of an artificial reef. In May 2020, divers returned to the reefs to find a strikingly different scene than the first dive. Ulva, an early colonizing green alga, had taken claim to the top of each module and barnacles had wrapped themselves around the exterior. Blue crabs and sea stars also started to show up, feasting on the various mollusks and crustaceans that had attached themselves to the reef. After being exposed to its first winter season, the Sabin Point Artificial Reef showed no evidence of scouring or movement.

Seasonally, as waters begin to warm, striped bass and tautog make their way through the upper Narragansett Bay to the Providence River. Across all 12 survey stations in the RIDEM and TNC Providence River fish pot project, fish abundance has been highest during the May–July sampling events. In this survey we caught the most tautog at Sabin Point, and diver observations were no different. In July, the dive team observed a tremendous number of fish utilizing the artificial reef. There were schools of silversides swimming atop the reefs, sounds of foraging tautog crunching constantly throughout the dive, and juvenile cunner swimming in and out of the reef modules. In addition to the juvenile wrasse, an adult male tautog had also decided to check out the reef, likely resting up before heading back to the Bay. As fish utilization increased on the reef throughout the field season, we also found evidence of higher recreational fishing activity at this location. Compared to the winter and late summer periods, the greatest amount of fishing gear accumulated between the May and July dive surveys. After the July 2020 survey, new signage was placed on the pier fencing, helping orient folks to the reef ball locations and to cast near the reef without losing gear, which has significantly decreased the occurrences.

It’s now been 2.5 years since the Sabin Point Artificial Reef was constructed, gear interactions are down, shellfish biomass has increased, and community structure is evolving past primary succession. During the 2021 field season we documented a major shift in reef ball succession, with the colonization of the first blue mussel set. The reefs are now covered with blue mussels, and some oysters as well. In addition, juvenile finfish abundance continues to increase, water clarity has improved near the reef balls, and adult tautog continue to be seen resting inside the reef modules. Where there was little structure in the waters surrounding Sabin Point before, there is now more beneficial structure for fish to colonize and feed. Based on the monitoring work so far, there seems to be higher fish abundance at this location than before the reef was built. Through this work, we’re aiming to enhance the abundance of legal-sized species (e.g., tautog, black sea bass, scup, striped bass) that are available to catch at this location.

Divers from RIDEM and TNC will continue to monitor the succession of the reef over time. The location of the Sabin Point Artificial Reef can be found on the NOAA Nautical Chart 13224 (Providence River and Head of Narragansett Bay) denoted as the Fish Haven on the south side of Sabin Point Park. The Sabin Point project will be used as a pilot study for the use of Reef Balls™ in Rhode Island waters and to identify monitoring guidelines for future artificial reef projects. The reef will be sampled once a month from May to October using fish pots, and additional dive surveys will be conducted over several years to monitor the reef productivity. From our work, we will establish fish habitat linkages by comparing productivity estimates on artificial reefs in relation to sand flat controls, and other important finfish habitats such as, oyster reefs, kelp, and eelgrass. For more information on the Sabin Point Artificial Reef, please contact Patrick Barrett ([email protected]; RIDEM DMF) or Will Helt ([email protected]; TNC).

Literature Cited

Caddy, John F. “How Artificial Reefs Could Reduce the Impacts of Bottlenecks in Reef Fish Productivity within Natural Fractal Habitats.” Artificial Reefs in Fisheries Management, by Stephen A. Bortone, CRC Press, 2011, pp. 45–64.

Powers, S., Grabowski J.H., Peterson C. H., & Lindberg W.J. (2003). Estimating enhancement of fish production by offshore artificial reefs: uncertainty exhibited by divergent scenarios. Marine Ecological Progress Series, 264: 265–27