Milford Lab's GoPro Aquaculture Project
Using GoPro Cameras to Understand Interactions Between Shellfish Aquaculture Gear and the Environment
- If oyster aquaculture cages provide habitat similar to that of naturally occurring rock reef environments,
- If cage densities associated with shellfish farming attract fish differently than single cages placed in areas with little natural structure, and
- If different styles of oyster aquaculture cages provide different habitat services to the local fish community.
Shellfish aquaculture can increase food production, create economic opportunities in coastal areas and enhance natural harvests. To foster successful, responsible, and sustainable aquaculture for the future, we need to understand how aquaculture gear may interact with marine ecosystems. Off-bottom multi-tiered oyster cages are growing in popularity as a method for culturing large numbers of oysters on a small footprint. These cages create complex structures that may attract fish and other animals seeking food sources, shelter, and refuge from water currents or protection from predators. Because of the cages' structure, they may function like naturally occurring rock reefs, providing beneficial habitat to ecologically and economically important fish and invertebrates.
Informing Decision Makers
Understanding if and how oyster cages function like naturally occurring habitats may help with regulatory and permitting processes when siting new shellfish farms. Regulatory challenges have been identified as one of the major bottlenecks to shellfish aquaculture expansion in the US. Close partnership with the NOAA Greater Atlantic Regional Fisheries Office ensures that the results from this study will be useful to the regulatory community.
Comparing Aquaculture Gear to Natural Habitat
Naturally occurring rock reefs create habitat complexity in an often otherwise flat and featureless landscape. Rock reefs add vertical height in the water column, crevices and shading for hiding, and surfaces on which epibenthic organisms can colonize and grow. Complex habitats like these often have greater density and diversity of species than a less complex habitat like a flat seafloor. For this reason, oyster cages may be providing benefits similar to those of rock reef habitats. While few studies have investigated aquaculture gear as habitat, extensive anecdotal evidence from commercial shellfish growers suggests that both fish and invertebrates may be using the gear as habitat.
Comparing Oyster Cultivation Methods
The oyster aquaculture industry employs a variety of cultivation methods, and differences in gear structure may influence how farms interact with the local fish community. We examined two commonly-used styles of oyster bottom cage, to see if structural differences affected fish abundance, community composition, and behavior. Shelf and bag oyster cages have three open shelves with bags of oysters, which creates a variety of spaces for fish to use. Stacked tray cages have three enclosed trays of oysters with smaller sized openings, which may restrict the size of fish that are able to access the cage interior.
Study Site Locations
Study sites are all located in Long Island Sound. The comparison of shellfish farm, bare seafloor, and rock reef occurred in Milford, Connecticut, in partnership with the Charles Island Oyster Farm. The comparison of cage styles was conducted on three oyster farms: the Charles Island Oyster Farm, Copps Island Oyster Farm in Norwalk, Connecticut, and Hummock Island Oyster Farm in Westport, Connecticut.
We used a series of GoPro cameras to record activity around the structures and document the abundance and behavior of fishes around shelf and bag style oyster cages and naturally occurring rock reef habitat. Using cameras as opposed to diver observations reduced the amount of human interference with fish activity. During all camera deployments near cages or boulders, timers were used to record video for 8 minute intervals every hour from 7 a.m to 7 p.m over a complete 12-hour tidal cycle. This enabled us to sample fish abundance and activity through changing environmental conditions over the course of a single day.
Cameras on Oyster Cages
Oyster cages were outfitted with two cameras: one mounted to record activity along the horizontal surface across the top of the cage, like a periscope, and one mounted to hang down from the corner of the cage to record activity along two sides of the cage and the area where the cage rests on the seafloor. Cameras were deployed by boat on cages, video recording started the following day and cameras were retrieved two days later. The oyster cages themselves stayed in the water for the entire field season.
Cameras on Natural Habitat
To record activity at naturally occurring rock reef habitat, we constructed four "T-platform" stands with dual camera mounts. We then placed the platforms near boulders within the rock reef site where they remained for the entire field season. Divers then put the cameras on
the T-platforms and retrieved the cameras two days later. The two cameras provided a field of view similar to that provided by our oyster cage camera system: one looked across the top of the boulder and one looked down the side of the boulder to where it met the seafloor.
Cage Placement at Milford Shellfish Farm
To understand if oyster cage density affected fish abundance and behavior, we placed four cages about 50 meters apart at the inshore site adjacent to the oyster farm, and four cages about 90 meters apart at the inshore mixed-feature habitat. We employed the same recording approach as used for the cage/reef comparison.
Cage Placement Across Multiple Oyster Farms
To compare fish interactions with different styles of oyster cages, we placed cage pairs at three Connecticut shellfish farms. Two cages of each type were deployed at shellfish farms in Milford, Norwalk, and Westport, to compare fish interactions between cage styles at multiple farms across a broader geographic area. Video was collected using timers as previously described.
During camera deployments, we also collected environmental data. We used HOBO Pendant® Temperature/Light 64K Data Loggers to record water temperature and light intensity every 15 minutes throughout every deployment. Light is an important factor affecting visibility and video quality and it may influence fish behavior. Because changing tidal currents may also influence how fish interact with cages and boulders within rock reefs, we used Lowell TCM-1 tilt current meters to collect information on speed and direction of water currents. Measurements were taken once every minute throughout each deployment. A current meter and temperature/light data logger was attached to one cage at each field site and to a spare T-platform at the rock reef. Using handheld YSI probes, we collected additional environmental data (i.e., salinity, dissolved oxygen) during deployment and retrieval trips to each site.
Describing Fish Communities using Environmental DNA (eDNA)
When fish and other animals swim, they shed scales, tissue, and waste, leaving traces of DNA in the water. Although this DNA is diluted, it can be extracted and analyzed. Each time we retrieved our GoPro cameras, we collected water for environmental DNA (eDNA) analysis. The eDNA method we used combined DNA-based identification with high throughput next generation sequencing to characterize the fish communities associated with oyster cages and rock reefs. Using eDNA we hoped to detect fish that were in the area surrounding the cages or rock boulders, but that were not seen in video. This may help create a more complete picture of fish community composition than video alone. Compared to capture-based methods, eDNA analysis is a comprehensive, rapid, non-invasive, and cost-effective method.
To date, we've observed 16 species of fish in our videos, associating and interacting with oyster cages. The four most common species observed in video have been:
- Black sea bass
Less-commonly observed species in videos include:
- Banded rudderfish
- Naked goby
- Red hake
- Smallmouth flounder
- Striped bass
- Striped sea robin
- Summer flounder
- Windowpane flounder
- Yellow jack
We’ve also observed a few fish species that have fallen out of cages during camera deployment/retrieval, but were not yet observed in video, including:
- Conger eel
- Oyster toadfish
- Rock gunnel
Identifying fish to species level and counting fish are only the first steps in our video analysis.
We've partnered with fish ecologist Dr. Pete Auster from the University of Connecticut and the Mystic Aquarium to identify and quantify the different ways that fish are using oyster cages. So far we've seen fish feeding on the epibenthic fouling organisms growing on the cages, little fish escaping from bigger fish by darting inside the cage itself, and even female fish retreating inside the cage to escape male fish of the same species.
Our analysis of eDNA samples collected during summer 2017 was recently published in Frontiers in Marine Science.
The GoPro Project Team would like to acknowledge the following individuals who assisted with the project:
Arthur Allen (US Coast Guard Office of Search and Rescue) | Eileen Bates (Bowdoin College/Summer Intern) | Bobbi Bevacqua (Western Washington University/Summer Intern) | Jimmy Bloom (Copps Island Oysters) | David Carey (State of Connecticut Aquaculture Division) | Calandria DeCastro (NOAA Corps) | Kristin DeRosia-Banick (State of Connecticut Aquaculture Division) | Bridget Ferriss (NOAA Alaska Fisheries Science Center) | Keith Golden (NOAA Corps) | Robert Granfield (Grower) | Kristen Jabanoski (Northeast Fisheries Science Center) | Shannon Kelly (State of Connecticut Aquaculture Division) | Kevin Madley (NOAA Greater Atlantic Regional Fisheries Office) | Deaven Maull (Washington College/Summer Intern) | Max Mauro (University of Maine/Summer Intern) | Jeff Northrup (Hummock Island Oyster Company) | John Pinkowski (Atlantic Clam Farms) | Rachel Precious (Copps Island Oysters) | Brandon Rose (Eckerd College/Summer Intern) | Gary Salce (G&B Shellfish Farm) | Beth Sanderson (NOAA Northwest Fisheries Science Center) | Alison Verkade (NOAA Greater Atlantic Regional Fisheries Office) | Charles Viens (Charles Island Oyster Farm)
- Commercial shellfish growers:
- Mystic Aquarium
- NOAA Greater Atlantic Regional Fisheries Office
- NOAA Northwest Fisheries Science Center
- Northeastern University
- Rutgers University
- State of Connecticut Aquaculture Division
- The Nature Conservancy
- US Coast Guard Office of Search and Rescue
- University of Connecticut
Citizen ScienceWe've created a citizen science guide to help growers capture high quality underwater footage of their aquaculture gear to monitor the ecosystem interactions:
- Using underwater video to observe aquaculture gear in Long Island Sound - A Citizen Science Guide (Updated 2020)
Rutgers University received funding from the Northeastern Regional Aquaculture Center to investigate fish and invertebrate interactions with oyster aquaculture gear and natural habitats using GoPro cameras in New Jersey. Their project engages oyster growers in Barnegat Bay that use floating oyster bags, and oyster bottom cages. Natural habitats included a marsh edge, and bare sandy bottom. Scientists have posted video clips from the project on the lab’s YouTube channel, and you can find more project information at the lab’s website.
The Nature Conservancy and Northeastern University have partnered to investigate how oyster farming gear provides habitat for other marine species using GoPro cameras in Massachusetts. They are working with commercial growers in Duxbury and Cotuit who use shelf-and-bag bottom cages, bottom trays, and OysterGro gear on both intertidal and subtidal farms. Natural habitat and control sites include constructed oyster reef, rocky reef, and bare sediment. The Nature Conservancy produced a video about this local project and how it contributes to the organization’s global aquaculture program.
- Capturing Life on Shellfish Farms (Story Map)
- NOAA Fisheries Lab Helps Shellfish Growers Become Citizen Scientists
- Science on the Half Shell: Milford Lab Tour for Kids Grades 2-8 (Recorded Webinar)
- Window to an Underwater World: Milford scientists evaluate aquaculture oyster cages as habitat using GoPro cameras
- NOAA Scientists Monitoring Connecticut Aquaculture (CT Department of Agriculture)
- Aw Shucks: Scientists Use GoPro to Study Oyster Habitats
- GoPro cameras let scientists know how fish act near oyster cages
- Collaborative research with the Northwest Fisheries Science Center (Outreach Handout)
- Documenting the Ecosystem Services Provided by Oyster Aquaculture Gear (Outreach Handout)