Gillian Phillips

Shelter‐oriented temperate reef fish species are known to utilize oyster aquaculture cages as habitat. To determine whether differences in the structural design of cages affects fish association with aquaculture gear, underwater video census was used to compare fish abundance, and community composition on two off‐bottom cage designs (shelf and bag vs. stacked tray) for aquaculture of eastern oysters ( Crassostrea virginica ) at farms located in Milford, Norwalk, and Westport, Connecticut (CT) on seven occasions between June and September 2019. Recording on shelf and bag cages was also conducted intermittently at Milford only from 2017 to 2022. Black sea bass, cunner, scup, and tautog were observed throughout all study periods, at all locations, and on both cage designs. During 2019, abundance of black sea bass, tautog, and total fish abundance varied across farms. There were no statistically significant differences in individual species abundance or in overall fish community composition between cage designs. The shelf and bag cages provided a greater volume of accessible interior space to fish with more epifaunal growth on surfaces as compared to stacked tray cages. Seasonally, fish abundance was highest from July to September, declined in November, remained low through winter, and increased in late April. While the maximum abundance of the most common fish varied among years, these species were consistently present during all study years. Our results suggest that shelf and bag and stacked tray cages provided equivalent habitats for temperate reef fish, and that oyster farms in Long Island Sound consistently provided habitat to these species from late spring through fall over 6 years of observations.

Cultivation of eastern oysters using aquaculture gear increases habitat for temperate reef fish. Cunner ( Tautogolabrus adspersus ), scup ( Stenotomus chrysops ) and tautog ( Tautoga onitis ) inhabit a variety of complex natural and manmade habitats, including oyster aquaculture cage farms. Underwater video was recorded on two cage farms and a rock reef during May–September 2018 to quantify fish behavioural interactions and to assess ecological services provided by aquaculture gear, relative to natural structured seafloor. To collect video, action cameras were mounted on four study cages at a high‐density farm of 40–100 commercial cages (dense farm), on four single cages interspersed on low relief seafloor (sparse farm) and adjacent to four boulders on a rock reef (rock reef), within an embayment off Milford, Connecticut in Long Island Sound (NW Atlantic). Video was recorded hourly in 8‐min segments from 7 AM to 7 PM. Behaviours associated with habitat provisioning (e.g., courtship/reproduction, escape from predators, foraging, sheltering, schooling/grouping, territoriality) were observed for all three fish species on cages and boulders. Foraging and sheltering activity in cunner was significantly higher on cages than boulders while territorial behaviour occurred more frequently on boulders. Instances of escape from predators, foraging and sheltering behaviours in scup and tautog were significantly higher on cages than on boulders. Courtship/reproduction, grouping and territoriality were also higher on cages than boulders in tautog. Our results suggest that oyster cages confer ecological services that fulfil the basic biological and functional requirements of reef‐oriented fish, and provide habitat attributes afforded by natural rock reefs.

Objective: Black Sea Bass Centropristis striata are a temperate reef finfish that occupy natural and artificial structured habitats. This study used fish behavior, condition indices, and production estimates to evaluate how oyster aquaculture cages serve as artificial reefs for Black Sea Bass in central Long Island Sound, USA. Methods: Underwater video was recorded on oyster farms and a natural rock reef to identify and quantify the behavior of Black Sea Bass that is associated with oyster aquaculture cages and boulders. Juvenile Black Sea Bass were sampled from farms and reefs in Clinton and Milford, Connecticut, to assess individual energy density and relative condition factor as measures of habitat quality. Proximate analysis was conducted to develop a predictive regression for percentage of dry weight and energy density in juvenile Black Sea Bass, which was then applied to estimate energy density in fish that were collected from farms and reefs. The abundance of young-of-the-year Black Sea Bass was used to quantify fish production on the oyster farms. Results: Significantly greater shelter and grouping activity were observed on cages than were observed among boulders. Instances of courtship/reproduction in mature fish, escape, foraging, and territorial behavior were statistically similar across the cage and boulder habitats. The condition metrics of energy density and relative condition factor showed no difference in the physiological status of juvenile fish that inhabited farms versus reefs. The enhanced production of Black Sea Bass was estimated to be 4.1 kg/100 cages per year based on higher abundance of young-of-the-year fish on farms relative to the rock reef reference habitat. Conclusions: Our results suggest that aquaculture gear provides valuable habitat services that are similar to those obtained via other man-made structures that are considered essential fish habitat for Black Sea Bass throughout their life history.

Human usage of coastal water bodies continues to increase and many invertebrates face a broad suite of anthropogenic stressors (e.g., warming, pollution, acidification, fishing pressure). Underwater sound is a stressor that continues to increase in coastal areas, but the potential impact on invertebrates is not well understood. In addition to masking natural sound cues which may be important for behavioral interactions, there is a small but increasing body of scientific literature indicating sublethal physiological stress may occur in invertebrates exposed to high levels of underwater sound, particularly low frequency sounds such as vessel traffic, construction noise, and some types of sonar. Juvenile and sub-adult blue crabs (Callinectes sapidus) and American lobsters (Homarus americanus) were exposed to simulated low-frequency vessel noise (a signal was low-pass filtered below 1 kHz to ensure low-frequency content only) and mid-frequency sonar (a 1-s 1.67 kHz continuous wave pulse followed by a 2.5 to 4.0 kHz 1-s linear frequency modulated chirp) and behavioral response (the animal’s activity level) was quantified during and after exposure using EthoVision XT™ from overhead video recordings. Source noise was quantified by particle acceleration and pressure. Physiological response to the insults (stress and recovery) were also quantified by measuring changes in hemolymph heat shock protein (HSP27) and glucose over 7 days post-exposure. In general, physiological indicators returned to baseline levels within approximately 48 h, and no observable difference in mortality between treatment and control animals was detected. However, there was a consistent amplified hemolymph glucose signal present 7 days after exposure for those animals exposed to mid-frequency sound and there were changes to C. sapidus competitive behavior within 24 h of exposure to sound. These results stress the importance of considering the impacts of underwater sound among the suite of stressors facing marine and estuarine invertebrates, and in the discussion of management actions such as protected areas, impact assessments, and marine spatial planning efforts.

We analyzed experimental behavioral data on temperature preference for the pseudothelphusid crab Neostrengeria macropa (H. Milne Edwards, 1853) in the