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Multi-tiered oyster aquaculture cages may provide habitat for fish assemblages similar to natural structured seafloor. Methods were developed to assess fish assemblages associated with aquaculture gear and boulder habitat using underwater video census combined with environmental DNA (eDNA) metabarcoding. Action cameras were mounted on 3 aquaculture cages at a commercial eastern oysterCrassostrea virginicafarm (‘cage’) and among 3 boulders on a natural rock reef (‘boulder’) from June to August 2017 in Long Island Sound, USA. Interval and continuous video recording strategies were tested. During interval recording, cameras collected 8 min video segments hourly from 07:00 to 19:00 h on cages only. Continuous video was also collected for 2-3 h on oyster cages and boulders. Data loggers recorded light intensity and current speed. Seawater was collected for eDNA metabarcoding on the reef and farm. MaxN measurements of fish abundance were calculated in video, and 7 fish species were observed. Black sea bassCentropristis striata, cunnerTautogolabrus adspersus, scupStenotomus chrysops, and tautogTautoga onitiswere the most abundant species observed in both oyster cage and boulder videos. In continuous video, black sea bass, scup, and tautog were observed more frequently and at higher abundance on the cage farm, while cunner were observed more frequently and at higher abundance on boulders within the rock reef. eDNA metabarcoding detected 42 fish species at the farm and reef. Six species were detected using both methods. Applied in tandem, video recording and eDNA provided a comprehensive approach for describing fish assemblages in difficult to sample structured oyster aquaculture and boulder habitats.

Predation is an important process influencing the structure of fish communities. There are multiple approaches used to quantify predatory interactions, and all approaches are beneficial but have their limitations. For example, food habit studies only represent results of successful predation events, direct observations by divers are time limited by both depth and temperature as well as observer effects, acoustic approaches cannot directly identify species, and video has field-of-view constraints when using standard cameras. While no approach is without constraints, the recent availability of small off-the-shelf virtual reality (VR) video cameras that can be used in marine environments offers a more spatially comprehensive field-of-view for conducting studies of community composition and species interactions both on the seafloor and in the overlying water column. Here, we demonstrate an approach for collection and analysis of data from stationary VR video to quantify predator-prey interactions at subtropical reefs in Gray’s Reef National Marine Sanctuary (NW Atlantic). This approach does not substitute for other widely used census and behavioral research approaches but augments those with unique analytical products and interpretation.

Glacier Bay National Park and Preserve (GBNPP) in Southeast Alaska is a system of glaciated fjords with a unique and recent history of deglaciation. As such, it can serve as a natural laboratory for studying patterns of distribution in marine communities with proximity to glacial influence. In order to examine the changes in fjord-based coral communities, underwater photo-quadrats were collected during multipurpose dives with a remotely operated vehicle (ROV) in March of 2016. Ten sites were chosen to represent the geochronological and oceanographic gradients present in GBNPP. Each site was surveyed vertically between 100 and 420 meters depth and photo-quadrats were extracted from the video strip transects for analysis. The ROV was equipped with onboard CTD which recorded environmental data (temperature and salinity), in order to confirm the uniformity of these characteristics at depth across the fjords. The percent cover and diversity of species were lowest near the glaciated heads of the fjords and highest in the Central Channel and at the mouths of the fjords. Diversity is highest where characteristics such as low sedimentation and increased tidal currents are predominant. The diverse communities at the mouths of the fjords and in the Central Channel were dominated by large colonies of the Red Tree Coral, Primnoa pacifica, as well as sponges, brachiopods, multiple species of cnidarians, echinoderms, molluscs and arthropods. The communities at the heads of the fjords were heavily dominated by pioneering species such as brachiopoda, hydrozoan turf, the encrusting stoloniferan coral Sarcodyction incrustans, and smaller colonies of P. pacifica. This research documents a gradient of species dominance from the Central Channel to the heads of the glaciated fjords, which is hypothesized to be driven by a combination of physical and biological factors such as glacial sedimentation, nutrient availability, larval dispersal, and competition.

Marine animal forests (MAFs) are constituted by dense aggregations of epibenthic and emergent animals, chiefly members of Porifera (sponges), Cnidaria (hydrozoans and anthozoans, including corals), and Bryozoa. Their three-dimensional structure and collective spatial complexity provide a diversity of habitats for associated fauna.

Long Island Sound (LIS) is a large estuary on the Atlantic coast of the highly developed northeast United States. However, limited spatially comprehensive habitat information has been available at sufficient resolution to inform planning and management of conflicting uses. A pilot project was conducted at a site with diverse topography and sediment characteristics in central LIS. The aim of the study was to develop methodologies to characterize the variety of benthic habitats and infaunal and epifaunal communities. This information was then used to produce habitat maps to inform stakeholders and decision-makers. Backscatter was processed using supervised segmentation with final acoustic “habitat” patches defined by sediment grain size, bathymetry, slope, and a topographic roughness index. Ecological attributes were determined using diversity indices and multivariate and image analyses of species composition data collected seasonally via grab samples, photography, and video. Some community dominants exhibited stability across seasons while others were seasonal in occurrence. Linkages between species and community distributions to seafloor characteristics occurred across multiple spatial scales. An integrated habitat map synthesized the general characteristics of seafloor habitats and associated species to provide a first order visualization of this complex subtidal landscape.

Studies of mixed-species groups of animals can reveal emergent complexities of collective behaviors. In this study we collected data on mixed-species hunting groups composed primarily of piscivorous fishes (species composition, abundance, behavioral interactions) and used both multivariate and network analyses to quantify pair-wise and guild level behavioral relationships. Our results indicate that such collective behaviors exhibit consistent patterns of associations (33 species with 282 pair-wise links within the observed network) with 10 dominant species accounting for 60% of pair-wise interactions. Species richness within groups varied (mean = 2.4, range 2-6 species) as did group size (mean = 8.1 individuals, range 2-80). Mixed-species groups, in general, were composed of species representing morphologically diverse forms that appeared to enhance access to shelter sites and implement diverse strategies for prey capture. It is noteworthy that the composition of groups did not reflect the relative abundances of their component species within the overall community of fishes, suggesting that group membership was an elective choice. The identification of these patterns, assuming they are persistent features of these communities, can be used as a foundation for studies to assess dynamics of mixed-species relationships, rates of predator success based on group membership, demographic consequences, and responses to variations in habitat attributes and associated prey resources. Such information could be used to interpret the nature of multispecies interactions within predator communities and potentially aid in conservation and management. RESUMEN Estudios de grupos mixtos de animales puede revelar complejidades y sutilezas del comportamiento colectivo. En este estudio recolectamos datos sobre depredación de grupos mixtos de especies, compuestos principalmente por piscívoros (composición de especies, abundancia, interacciones) y usamos tanto análisis multivariado como de redes para cuantificar relaciones de comportamiento entre pares de especies y a nivel de gremios. Nuestros resultados indican que los comportamientos colectivos exhiben patrones consistentes de asociaciones (33 especies con 382 interacciones entre pares de especies dentro de la red) con 10 especies dominantes que constituyen el 60% de las interacciones entre dos especies. La riqueza de especies dentro de grupos varió (media = 2.4, ámbito 2-6 especies) cómo también el tamaño del grupo (media = 8.1, ámbito 2-80). Los grupos de especies mixtas, en general, estaban compuestos por especies con diversas morfologías que aparentemente aumentan el accesos a lugares estrechos y además, implementa diversas estrategias de captura de presas. Vale la pena resaltar que la composición de los grupos no reflejaba la abundancia relativa de las especies en la comunidad total de peces, sugiriendo que la membresía en el grupo era algo electivo. La identificaión de estos patrones, asumiendo que son características persistentes de la comunidad, se podrán usar en estudios para determinar la dinámica de las relaciones de grupos mixtos, tasa de éxito de depredación basado en la membresía del grupo, consecuencias demográficas y respuestas a varicaciones en las habitat y presas. Esta información servirá para interpretar la naturaleza de las interacciones multiespecíficas dentro de la comunidad de depredadores y potencialmente ayudar en la conservación y manejo de recursos.

The distribution and demographics of a population of Winter Flounder Pseudopleuronectes americanus were examined for changes related to habitat quality over a fishery-independent survey period of 29 years, encompassing an 82% decline in abundance. We tested for spatial and temporal variation in indicators of fitness to determine whether they revealed likely processes that resulted in the observed patterns of habitat use. We also assessed temporal changes in fitness and inferred changes in habitat quality associated with population decline. We focused on the condition of postspawn (resting) mature and immature fish of both sexes during a critical period of spring feeding prior to summer migration. Analysis of variance of individual condition indices (log10[length]–log10[weight] regression residuals) by sex/maturity group and time period identified consistent and significant differences among six survey strata. Highest condition indices were observed for fish that were captured in shallow (

Using a combination of data obtained from high-definition still images, video, and specimens collected during human-occupied submersible and remotely-operated vehicle dives spanning the period 2003 to 2014, we provide the first detailed characterization of the megabenthic assemblages in the lower bathyal on the New England and Corner Rise Seamounts in the Northwest Atlantic. Over all, the New England Seamounts east from Retriever to Nashville have a more diverse megabenthic fauna than Corner Rise, but the lowest diversity was observed on the three seamounts located closest to the continental margin. The megabenthic assemblage structure varies both within and across seamounts, and hierarchical cluster analysis revealed groups dependent on location (as measured by longitude) and depth, with substrate composition an additional but less significant factor at the regional scale. We conclude that the megabenthos assemblages in the bathyal Northwest Atlantic are determined, at the regional scale, by the water masses in which they reside.

We observed sea turtles with time-lapse video cameras (deployed for studies of fish behavior during June 2017) at “live-bottom” reefs in depths of 18–20 m within Gray's Reef National Marine Sanctuary off the coast of Georgia, USA (NW Atlantic). These reefs, sandstone ledges emerging from surrounding sand seafloor, were deeply undercut and apparently served as resting habitat for turtles to wedge themselves between sand seafloor and hard rock overhead. We observed 22 distinct individuals over 27 occurrences including 10 Caretta caretta (L.) (Loggerhead), 3 Chelonia mydas (L.) (Green Sea Turtle), and 9 unidentified to species based on individual markings. We documented resting periods up to 144 minutes (mean = 37.2 min, SD = 39.1). Notable was that most observations (67%) occurred during twilight and night periods. To put these video observations in perspective, we analyzed diver observations of 34 turtles encountered at the surface prior to and during visual fish census surveys (2010–2017) at 18 ledges. Those ledges had significantly taller and deeper undercuts than 18 other ledges with no turtles (ANOSIM P = 0.043 and SIMPER comparisons). These limited observations indicate time-lapse video of seafloor habitats along with diver surveys may yield new insights into sea turtles' habitat requirements, patterns of site fidelity, and ecological role as ecosystem engineers, as well as effects on sea turtles of coincident human uses such as fishing, vessel use, and recreational diving.

The dynamics of fish communities at tropical and sub-tropical rocky reefs are influenced in many cases by predation activity and predator-prey interactions. These processes usually follow specific diel patterns in reef areas with higher rates of these interactions occurring during the crepuscular periods. However, other factors such as habitat complexity and species-specific behavior may alter these patterns, increasing variability in species interactions. A better understanding of the dynamics of these patterns and processes would allow us to manage and monitor fish communities in these productive and vulnerable areas more efficiently. We investigated behavioral changes of predators and prey fish in sub-tropical "live-bottom" (sandstone) reefs at Gray's Reef National Marine Sanctuary (GRNMS), located 20 nautical miles off the coast of Georgia, USA, using fisheries acoustic methods in association with visual census and direct observation using SCUBA. Changes in co-location and habitat preferences of predators and prey over time throughout the diel cycle were investigated using species distribution models (MAXENT) based on habitat predictors and by means of spatial statistics. The results indicate that predator and prey distribution patterns changed considerably throughout the day. Prey and predator species exhibited complex spatial dynamics and behavior over diel periods, with prey modifying patterns of habitat use and spatial distribution, likely as a response of their interactions with predators. Crepuscular periods were confirmed to be the most active phases in terms of predator-prey interactions and consequently the most variable. The combination of tools and approaches used in this study provided valuable sources of information that support the inferences of predation risk-driven habitat selection of prey in this sub-tropical reef system.

Three theories of habitat use proposed for marine fishes, the constant density model (CDM), the proportional density model (PDM), and the basin model (BM), make contrasting pre- dictions of how the range, local density, and fitness change as population size changes. We tested model predictions using a survey of silver hake Merluccius bilinearis conducted by the National Marine Fisheries Service every spring and fall. Data on fish length, sex, weight, and reproductive status are collected. Despite a 50% population reduction over the time period of the survey, the geographic area occupied by silver hake did not change significantly. Local density in preferred habitat remained a constant proportion of the entire population. Fitness (as indicated by individ- ual condition) varied over a fine spatial scale, reflected in a pattern of spatial autocorrelation of 10s to 100s of kilometers. Fitness did not exhibit density dependence, except in one case, females in the fall, probably due to the higher energy needs of the females. The results indicate that silver hake conform to the PDM, a site-dependent model, and yet we found some evidence of density dependence in our measure of fitness. Site dependence may work in concert with density depend- ence to regulate population size. Sites silver hake depend on may be the spawning areas along the coast, which may already be in legislatively protected areas. Our study illustrates that an under- standing of habitat use is important for crafting conservation or management measures that lead to maintenance of a stable population.

National and international obligations to protect vulnerable species, communities, habitats, and ecosystems (VSCHEs) require greater attention as human uses extend to deeper water. These obligations increase the need for improved understanding of the distribution and abundance of VSCHEs to develop management actions. Data from low-speed vehicles that operate at the seafloor (e.g., remotely operated vehicles, camera sleds) predominate. These “low and slow” approaches, while providing high-resolution data, do not operate at the scale required for management. We suggest autonomous underwater vehicles (AUVs) flown at relatively high altitude and high speed over the seafloor as a “high and fast” approach to survey areas at the scale fisheries and other activities operate. We used REMUS 6000 AUVs to collect presence data for VSCHEs in a rapid assessment on Physalia Seamount. AUVs were programmed to collect digital images, side-scan sonar (120/410 kHz), and environmental parameters and could navigate a 40° slope. Our preliminary results of this approach, predicated on the assumption that coarse taxonomic resolution is adequate for management needs, indicates AUVs can be effective tools for large area surveys in short time periods.

Certification and eco-labeling schemes for the ecological sustainability of seafood have increased in recent years due, in large part, to consumer demand. While most attention has been focused on the population status and trends of target and bycatch species, the conservation of vulnerable species, communities, habitats and ecosystems (VSCHEs) has not consistently been addressed in an adequate manner, especially in data-poor systems. Unfortunately knowledge of VSCHE distribution patterns is inadequate, and even the leading fishery certification agencies only broadly address impacts to VSCHEs. Little guidance has been given to third party certifiers for gathering and evaluating appropriate information for assessing VSCHEs, and there is no explicitly precautionary method of assessing their vulnerability in an information poor environment. These shortcomings led to significant differences in how the impacts of fisheries on VSCHEs have been evaluated from one assessment to another, potentially resulting in a certified fishery when existing information suggests there are significant impacts. This study develops an explicit approach for data mining and evaluation for the eco-labeling certification process; proposes a precautionary method for assessing vulnerability of VSCHEs based on exposure, sensitivity and resilience and provides an example of how these can be integrated into existing fishery certification frameworks. This overall approach is also amenable for use by governmental agencies to advance conservation of VSCHEs within ecosystem-based management frameworks. & 2012 Elsevier Ltd. All rights reserved.

This work examined the potential for marine protected areas based on the efficient design of essential fish habitat (EFH) for juvenile life stages of economically important demersal fish species to represent non-exploited demersal fish species in the Gulf of Maine. Distribution and abundance data from research trawl surveys conducted from 1963–2000 were pooled into a 10-min lat/long square sampling grid and density per square of each species was calculated as the mean of counts from all surveys. A simulated annealing algorithm (Marxan) was used to identify minimum sets of 10-min squares that represented at least 10–30% of the regional abundance of each species under constraints for degree of spatial aggregation among sites. Numbers of non-exploited species in these sites, and species represented at abundance levels equal to or greater than the targets set for juveniles of economically important species were identified, and both were compared with mean totals from 100 sets of randomly drawn squares of equivalent number to simulation results. Percentages of non-exploited species among all scenarios varied from 81–97%. All species absent from simulation results were rare regionally. Species richness was lower in each case compared with randomly drawn squares, but only marginally. However, more species were represented in complementary sites at abundance levels equal to or greater than the targets set for economically important species. These results were interpreted with respect to a definition of biodiversity that includes species as well as functional and structural ecosystem components, and it was concluded that the dual objectives of fishery management and biodiversity conservation can be achieved, at least in some cases, within a single network of marine protected areas of moderate size. Copyright © 2013 John Wiley & Sons, Ltd.

Among species interactions, competition is obviously more nuanced to investigate than predation. Certainly there have been copious, seminal works on competition in marine and freshwater ecosystems, most often on research executed at smaller ecological scales such as rocky intertidal zones, coral reefs, or littoral zones, and often involving experimental manipulation. Such studies have typically emphasized organisms with relatively high site fidelity, and all have focused primarily at the individual level. Here we springboard from those studies to explore competition among marine fishes at broader spatiotemporal scales, scales at which fish populations are distributed, scales at which their associated fisheries operate and are managed, and as observed under ambient (i.e., nonexperimental) system dynamics. Inferring that competition might be occurring among marine fishes requires four conditions: opposite population trajectories, high spatiotemporal overlap, high dietary overlap, and some indication of resource limitation. We used those criteria to examine cases of species pairings from the Northeast United States Large Marine Ecosystem to ascertain if there are broadly applicable rules of thumb to determine when competition might be a significant consideration. We assert that such rules exist, and where competition is strongly suspected, we provide an empirically based method of calculating first-order, model-free interaction terms that can scope the potential magnitude of competitive effects. We do so very much cognizant of several caveats and theoretical considerations; but our main premise is that estimating and evaluating competition for marine fishes from extant, commonly available data is feasible, is highly germane, and has many valuable applications for multispecies and ecosystem models as we move toward ecosystem-based fisheries management.

Understanding the interactions and feedback mechanisms among species in marine communities is essential to the conservation and management of natural resources in the sea. Such interactions can mediate the distribution, abundance, and diversity of species within communities and across habitats, landscapes, and ecosystems. From a practical perspective, ecosystem approaches to ocean management will need to account for those interactions that drive variation at the scale at which management operates and perhaps point to the scale at which management should strive to operate. The 8th William R and Lenore mote Symposium focused on the role that diverse types of species interactions-that invisible fabric of nature-play in marine ecosystems within which fisheries are embedded and facilitate the exchange of ideas about how to integrate such knowledge into realistic approaches to ocean management

Predator-prey interactions of large vagile fishes are difficult to study in the ocean due to limitations in the space and time requirements for observations. Small-scale direct underwater observations by divers (ca. 2 to 100 s km2) are traditional approaches for surveying fish. However, large piscivorous predators identify and attack prey at the scale of meters to tens of meters. Dual-Frequency Identification Sonar (or DIDSON) is a high-resolution acoustic camera operating in the MHz range that provides detailed continuous video-like imaging of objects up to a range of 30 m. This technology can be used to observe predator-prey interactions at ecologically relevant space and time scales often missed by traditional methods. Here we establish an approach for quantifying predation-related behaviors from DIDSON records. Metrics related to predator and prey group size, prey responses to predation, predation rate, predator strategies, and the nonrandom use of landscape features by both predator and prey are described. In addition, relationships between patterns in these attributes are tested and issues regarding sampling strategies for future studies are discussed. We suggest that approaches combining direct visual observation and acoustic sampling at multiple scales are required to quantify variation in these relationships across underwater landscapes.

Direct visual and acoustic observations at subtropical reefs off the southeast united states and northeast Gulf of mexico revealed a complex web of behavioral interactions within and between mid-water and demersal guilds of piscivorous fishes. While mixed-species groups of mid-water and demersal piscivores stalked and attacked common prey species independently, facilitative behaviors between mid-water and demersal piscivores were common in each region. In the latter case, prey reduced nearest neighbor distances and retreated toward the seafloor during predatory attacks by mid-water fishes. Demersal fishes subsequently attacked and consumed prey in these ephemeral high density patches. Aggregations of fishes in other trophic guilds, unassociated with predation events, modified movements of prey fishes and provided camouflage for piscivores that occurred within and along the periphery of those aggregations. Demersal piscivores often assumed the role of mid-water piscivores when the abundance of mid-water piscivores was low and when demersal piscivores were larger than mid-water species. Young-of-the-year great barracuda, Sphyraena barracuda (edwards, 1771), also assumed this role, generally when other piscivores were absent. Such behavioral interactions appear to be common in these communities. If predator-prey relationships are regularly facilitated by these types of mixed-species interactions, such facilitative behaviors may be important in terms of population processes (e.g., yielding increases in prey consumption with resultant increases in growth rate, and fecundity). A framework for testing such predictions provides a pathway for assessing the population consequences of such interactions.

Hare, J.A., Manderson, J.P., Nye, J.A., Alexander, M.A., Auster, P.J., Borggaard, D.L., Capotondi, A.M., Damon-Randall, K.B., Heupel, E., Mateo, I., O'Brien, L., Richardson, D.E., Stock, C.A., and Biege, S.T. 2012. Cusk (Brosme brosme) and climate change: assessing the threat to a candidate marine fish species under the US Endangered Species Act. – ICES Journal of Marine Science, 69: 1753–1768. In the Northwest Atlantic Ocean cusk (Brosme brosme) has declined dramatically, primarily as a result of fishing activities. These declines have led to concern about its status, which has prompted reviews under the US Endangered Species Act and the Canadian Species at Risk Act. Changes in distribution and abundance of a number of marine fish in the Northwest Atlantic have been linked to climate variability and change, suggesting that both fishing and climate may affect the status of cusk. Our goal was to evaluate potential effects of climate change on Northwest Atlantic cusk distribution. Coupling a species niche model with the output from an ensemble of climate models, we projected cusk distribution in the future. Our results indicate cusk habitat in the region will shrink and fragment, which is a result of a spatial mismatch between high complexity seafloor habitat and suitable temperature. The importance of habitat patch connectivity for cusk is poorly understood, so the population-level consequences of climate-related habitat fragmentation are uncertain. More broadly, climate change may reduce appropriate thermal habitat and increase habitat fragmentation for other cold-water species in the region; thereby, increasing the potential for regional overexploitation and extirpation.

Discerning the role that facilitative behavioral interactions in mixed species groups of hunting piscivores play in growth and survivorship is important both in our fundamental understanding of fish community dynamics and for developing conservation strategies. In this study we collected data on mixed-species hunting groups (species composition, numbers, behavioral interactions) and used both multivariate and network analyses to quantify pair-wise and guild level behavioral relationships. Our results demonstrate that collective behaviors in mixed species hunting groups exhibit consistent patterns of associations within a set of dominant species (10 of 32 species within the network) and are a common attribute of this functional guild within the shallow fish community at Isla del Coco (to 80 m depth), Pacific Costa Rica. Indeed the removal of only a few dominant species from the behavior web model, to simulate overfishing, reduced the number of pair-wise linkages by 57% (32 species with 282 pair-wise links to 28 species with 122 links). The identification of these patterns, assuming they are persistent features of these communities, can be used as a foundation for time-series monitoring to assess status and change in ecological interactions within the higher trophic level guild of fishes. That said, more work is needed to understand the temporal dynamics of network linkages and intensity of interactions as prey resources vary in distribution and abundance. Such information could be used to interpret the nature of multispecies interactions within predator communities and serve as an aid in conservation and management.

The shallow waters around Isla del Coco, Costa Rica, have the highest density of apex predators within the Eastern Tropical Pacific. This represents a unique opportunity to assess the structure of predatory interactions in a community relatively unimpacted by fishing. Facilitation of predation has commonly been observed in shallow reef systems, limited in depth by observations via scuba divers. Here we present a preliminary catalog of facilitative behavioral interactions between 12 taxa of deepwater piscivores at Isla del Coco and Las Gemelas Seamount in the Eastern Tropical Pacific, collected via video from submersible vehicles to depths of approximately 311 m from 2002-2012. Observations were ad hoc and likely represent only a portion of the web of interactions that occur in this ecological setting. That such interactions can be observed to 300 m during the narrow time frame of submersible dives suggests that direct behavioral facilitation of piscivory may play a significant role in the apex predator guild of deepwater fishes. Investigating the extent and population-community consequences of such interactions will provide valuable insight into patterns and processes that occur in communities protected from direct fisheries as well as focus conservation actions. Rev. Biol. Trop. 64 (Suppl. 1): S187-S196. Epub 2016 February 01. Las aguas someras alrededor de la Isla del Coco, Costa Rica, tienen la densidad más alta de depredadores tope del Pacífico Tropical Oriental (PTO). Esto representa una oportunidad única para estudiar la estructura de interacciones de depredadores en un sitio no impactado por la pesca. Facilitación de depredación ha sido observada en ambientes arrecifales someros, limitado a la profundidad de observación de buzos con tanques de buceo (scuba). Aquí presentamos un catálogo preliminar de interacciones de comportamientos facilitativos entre 12 taxones de piscívoros de aguas profundas de la Isla del Coco y el Monte Submarino Las Gemelas en el PTO. Esto se hizo analizando videos tomados con vehículos sumergibles hasta una profundidad de 311m entre el 2002 y el 2012. Las observaciones fueron ad hoc y probablemente representan solo una fracción de las redes de interacciones que se dan en estos ambientes. El que estas observaciones se puedan observar hasta más de 300m, en períodos de tiempo muy cortos de las inmersiones con sumergibles, sugieren que el comportamiento facilitativo directo debe jugar un rol importante para los depredadores tope de aguas profundas. Investigando el alcance y las consecuencias en poblaciones-comunidades de tales interacciones pueden proveer valiosas perspectivas sobre patrones y procesos que se dan en comunidades protegidas de la pesca directa como también para enfocar acciones de conservación.

The Asian shore crab Hemigrapsus sanguineus invaded the coast of Long Island Sound approximately twenty years ago and has become hyper-abundant and the most common crab species throughout the intertidal region. The success of the species is hypothesized to be due to reduced predation pressure in the invaded region. Recent observations document the expansion of H. sanguineus into shallow subtidal habitats (i.e., up to 5 m depth and up to 180 crabs m − 2 in some habitats) where it is more accessible to a diversity of crustacean-eating predators. The role that higher trophic level predators might play in controlling populations of invasive species has seldom been investigated in marine communities. Here we conducted a series of prey-preference experiments under laboratory conditions to determine whether crustacean-eating fishes prefer H. sanguineus rather than native crab species, and to provide insight into how predator size and habitat type influence prey preference. Small size-class predators exhibited a clear preference for H. sanguineus in paired offerings of the invader versus native crab species while paired offerings for large size-class fishes resulted in mixed findings. Small size class predators demonstrated no preference when prey were set in a range of sediment type treatments (i.e., sand, pebble, cobble), while paired offerings for large size class predators resulted in mixed findings. In general, the results from this study support our hypothesis that H. sanguineus is preyed upon preferentially by native crustacean-eating fishes but sediment type and predator size play an important role in determining that preference. Preference for the invasive crab over the native prey items in some settings suggests prey switching could occur in areas where the invader is abundant. We suggest that future field studies focus on the role that crustacean-eating fishes can play in biological control of invasive crab populations and how management of predators can influence the impact of invaders.

Finfish abundance indices, produced from seasonal trawl survey data collected in Long Island Sound, were examined for changes in community composition related to the dynamics of water temperature from 1984 to 2008. In general, seasonal mean catch of species identified a priori as cold adapted significantly decreased while warm-adapted and subtropical species significantly increased over the time series. Bottom water temperature also significantly increased. As a group, annual abundance of cold-adapted species exhibited significant negative correlation with mean bottom water temperatures while warm-adapted species, but not subtropical species, exhibited significant positive correlation. Multivariate analyses identified a shift in community structure producing two primary year-groupings. Spring groupings were clearly delineated as 1984–1998 (cold period) and 1999–2008 (warm period). Autumn groupings were temporally discontinuous in the 1990s with group membership shifting between cold and warm peri...

Direct observations were made in June 2009 and 2010 of newly recruited young-of-year (YOY) Sphyraena barracuda (Great Barracuda; 50–80 mm total length) occuring on “live bottom” sub-tropical reefs off the southeast US at depths of 18–25 m. Counts of YOY fish from roving diver surveys along multiple reefs with under-cut ledges ranged from 0–122 individuals, indicating patchy distributions at the scale of individual reefs. Individual fish occured in groups of 2–20+, primarily along the undercut side of ledges, where dense schools of Haemulon aurolineatum (Tomtate), Decapterus punctatus (Round Scad), Decapterus macarellus (Mackeral Scad), Stenotomus chrysops (Scup), and Atherinid sp. (silverside) were concentrated. Groups of YOY Great Barracuda attacked, captured and consumed YOY Tomtate and Silverside that occured in schools in the water column adjacent to (just above the sediment-water interface) and directly above the undercut edge of the reefs. Prey reacted during attacks by reducing nearest nei...

From 2006 to date the submersible DeepSee has been used to study the deep waters in and around Isla del Coco National Park, Costa Rica. Over these years, images and samples have been collected at depths between 50 and 450 m. Here we present a catalogue of bony fishes recorded by the submersible in deep waters of Isla del Coco, 500 km south-southwest of mainland Costa Rica, and at Las Gemelas Seamount within the designated Seamounts Management Area, 50 km southwest of Isla del Coco. A database with video-images of bony fishes was created from videos taken by the submersible’s high-definition digital camera from 2006 to 2015. Additional information on the distribution of fishes was obtained from 11 dives (24.3 hrs) using the remotely operated vehicle Hela at Las Gemelas Seamount during February 2012. Images of bony fishes were obtained during 376 dives (365 DeepSee dives plus 11 Hela dives) in 18 different locations, and here we report on a total of 85 taxa (i.e. putative species). In this catalogue we present images that are the first color photographs published for some species. In other cases, identifications were possible only to the level of genus (11), family (5) or order (1); hence the information is presented in terms of putative taxa. Four new records are reported for Isla del Coco: Leptenchelys vermiformis (Ophichthidae), Hyporthodus mystacinus (Serranidae), Kathetostoma averruncus (Uranoscopidae), and Symphurus diabolicus (Cynoglossidae). Depth ranges of twenty-six species are expanded beyond previously published records; three were observed in shallower water, twenty-two in deeper water and one was observed both shallower and deeper than in previous reports. As might be expected, increased bottom time with the submersible resulted in additions to the list of documented species. This highlights the importance of maintaining systematic research efforts in the deep waters around Isla del Coco, both for scientific purposes as well as conservation.

We describe a commensal relationship between small (approximately 6 to 9 cm) deep-sea cusk eels, one tentatively identified as Barathrites sp. (Osteichthyes: Ophidiidae), and pancake urchins, both Hygrosoma petersi and Phorosoma placenta (Echinodermata: Echinothuriidae). These interactions were observed in situ using a remotely operated vehicle (ROV), deployed at depths of 1410 to 1775 m on three seamounts in the western North Atlantic (Bear and Rehoboth seamounts in the New England Seamounts and Yakutat Seamount in the Corner Rise Seamounts). Full motion video and still frames documented individual cusk eels associated with urchins in open fine-grained sediment and coral rubble habitats. Cusk eels foraged around the periphery of urchins and took refuge at the base and among the long spines on the aboral surface. We suggest that such associations provide juvenile cusk eels with shelter from predators or flow (or both) and access to prey far from other forms of refugia.

It is often assumed that visual survey data provide more accurate fish counts than conventional extractive gear. As a result, use of underwater vehicles to assess the abundance and distribution of fishes has increased rapidly over recent years. However, a review of observations reported for 48 demersal marine fish taxa showed that almost all respond in some way to underwater vehicles. Whether or not movements or changes in behavior affect survey bias is more difficult to assess. A simple conceptual model is presented to evaluate relationships between stimulus intensity, distances from the vehicle where reactions occur, and survey bias. Largest bias is caused by attraction or avoidance that occurs outside the field of cameras or observers. While light level and vehicle speed have been explored experimentally in a few cases, much remains to be learned about how bias varies among species, age groups, different vehicles, and operating conditions. Given poor understanding of survey bias, we recommend that surveys be conducted with minimum possible variation in operations and that vehicle time is devoted to experimental evaluation of methods. There is no good substitute for direct observations on fish behavior, distribution, and abundance; and survey design can be improved through experimentation.

Direct underwater observations at seamounts across the western North Atlantic basin revealed the presence of the false boarfish, Neocyttus helgae (Oreosomatidae), at depths of 915 to 1829 m. These observations extend the known range of this species across the North Atlantic basin and support the hypothesis that seamounts are stepping stones for dispersal. Fishes were associated with basalt habitats featuring corals and sponges (both nearly horizontal basalt sheets and steep cliffs) as well as depressions in sheets of basalt. These features provided refuge from flow and predators as well as immediate access to zooplankton and pelagic prey delivered by rapid currents. Encounters with fishes were primarily as single individuals or pairs. Territorial behaviors, such as raised dorsal spine and lateral display, occurred when submersible vehicles approached fish, suggesting that territorial defense is a common behavioral attribute.

There is a diversity of shapes and sensor configurations used in the design of autonomous underwater vehicles (AUVs). Cameras and lighting (for both still and video imaging) are common sensor systems and have traditionally been configured to produce orthogonal images of the seafloor. Such imagery provides invaluable small-scale, high-resolution data for studies of seafloor geology and sessile invertebrate communities. However, using orthogonal imagery to census the diversity of mobile fauna has limitations caused by avoidance. A simple analysis using species-individual curves demonstrated that species richness was generally lower in surveys using orthogonal images when compared to forward-looking oblique images despite encountering the same number of individual fishes. This pattern was consistent when contrasting data from separate AUV and ROV surveys at boulder reefs in the Gulf of Maine as well as from down-looking and forward-looking cameras simultaneously collecting video imagery from a camera sled in a variety of habitats. These results indicate a need to evaluate the effects of camera configuration on the performance of abundance and diversity indicators developed from image data acquired using AUVs and other vehicles. Further, we recommend that AUV designers endeavor to accommodate oblique angles for cameras and associated lighting within vehicle design parameters in order to support missions that improve detection of mobile fauna.

Little is known about the role that patterns of habitat selection play in mediating move- ment of Atlantic cod Gadus morhua, particularly in off-shore environments. We used acoustic teleme- try to study the movement of adult cod tagged at deep boulder reefs (DBRs) in the western Gulf of Maine. The movement of 65 cod tagged with acoustic transmitters was monitored by acoustic receivers deployed on the seafloor at 4 DBRs from May to September 2002 and September 2004 to February 2005. Each receiver encompassed an area of the seafloor of approximately 0.5 km 2 , and data on each fish were recorded for up to 95 d post-release. Twenty-three cod (35.4% of tagged fish) exhibited high site fidelity to the DBR where they were caught and released (recorded in >82% of the 1 h time bins), while 33 cod (50.8% of tagged fish) appeared to depart the area rapidly following release (recorded in

The continental margin off the northeastern United States (NEUS) contains numerous, topographically complex features that increase habitat heterogeneity across the region. However, the majority of these rugged features have never been surveyed, particularly using direct observations. During summer 2013, 31 Remotely-Operated Vehicle (ROV) dives were conducted from 494 to 3271 m depth across a variety of seafloor features to document communities and to infer geological processes that produced such features. The ROV surveyed six broad-scale habitat features, consisting of shelf-breaching canyons, slope-sourced canyons, inter-canyon areas, open-slope/landslide-scar areas, hydrocarbon seeps, and Mytilus Seamount. Four previously unknown chemosynthetic communities dominated by Bathymodiolus mussels were documented. Seafloor methane hydrate was observed at two seep sites. Multivariate analyses indicated that depth and broad-scale habitat significantly influenced megafaunal coral (58 taxa), demersal fish (69 taxa), and decapod crustacean (34 taxa) assemblages. Species richness of fishes and crustaceans significantly declined with depth, while there was no relationship between coral richness and depth. Turnover in assemblage structure occurred on the middle to lower slope at the approximate boundaries of water masses found previously in the region. Coral species richness was also an important variable explaining variation in fish and crustacean assemblages. Coral diversity may serve as an indicator of habitat suitability and variation in available niche diversity for these taxonomic groups. Our surveys added 24 putative coral species and three fishes to the known regional fauna, including the black coral Telopathes magna, the octocoral Metallogorgia melanotrichos and the fishes Gaidropsarus argentatus, Guttigadus latifrons, and Lepidion guentheri. Marine litter was observed on 81% of the dives, with at least 12 coral colonies entangled in debris. While initial exploration revealed the NEUS region to be both geologically dynamic and biologically diverse, further research into the abiotic conditions and the biotic interactions that influence species abundance and distribution is needed.

Observations of Atlantic hagfish Myxine glutinosa exploiting prey captured, but not fully consumed, by the horse star Hippasteria phrygiana and Jonah crab Cancer borealis are described. Such interactions are defined as encounter competition. These represent the first reported observations of this type of interspecific interaction for Atlantic hagfish.

We conducted an analysis of species associations using fish diversity and abundance surveys conducted in Bonaire Marine Park by recreational divers. We used data from the REEF (Reef Environmental Education Foundation) Fish Survey Project to compute Bray–Curtis similarity coefficients for all species pairs for the 100 most abundant species. We quantified relationships between species using hierarchical agglomerative clustering and non-metric multidimensional scaling (MDS) of the matrix of Bray–Curtis similarity coefficients. We identified three clusters of species from the analysis. MDS results showed species clusters occupied distinct regions across a continuous gradient of species in two-dimensional space, rather than form distinct clusters. While differences in habitat requirements can explain some of the pattern in pairwise species interactions, these results suggest that there are significant direct and indirect behavioral interactions mediating the distribution and abundance of species. Studies conducted to elucidate patterns of species-habitat relationships have been central to conservation planning for marine protected areas (MPAs). However, the role of behavioral interactions between species driving the dynamics of species composition within MPA networks, designed for representation of biological diversity, should be considered when selecting sites in order to be effective.

Essential fish habitat (EFH) is defined under U.S. federal law, which mandates its protection. Current single-species approaches to identifying EFH for suites of managed species have resulted in areas designated fo rp rotection that are so large that protecting fish habitat has been difficult in the context of fishery manage- ment. We evaluated the potential for simulated annealing, a type of mathematical optimization, as a tool for simultaneously identifying EFH for multiple species in four ecological regions of the eastern continental shelf of the United States. Data were obtained from a shelf-wide trawl survey with site-specific abundance informa- tion spanning 37 years. The data were averaged within units of a sampling grid with 10-minute squares. We used computer software with an objective function that includes a term for weighting the boundary length of selected sampling units and thereby identifies solutions that meet specific targets for representation under varying degrees of spatial aggregation. We defined representation as a percentage of the cumulative sampled abundance of individual species and examined the effects of these target values and spatial constraints on total (sea-surface) area and boundary length of solution sets. We also evaluated the algorithm for its ability to select areas where juveniles occurred at high densities as a proxy for habitat value. Annealing solutions covered less total area than would the combined habitats of individual species that capture the same proportion of popu- lation abundance. For most species in most solutions, high-density areas were selected in higher proportions to their relative abundance in a region and solutions contained less total habitat area and smaller boundary lengths. Additionally, sampling units were distributed among two or more discrete localities versus a single location for the same target level of representation. We suggest that simulated annealing is a viable tool for EFH planning with the potential for identifying more spatially conservative habitat areas for protection than a single-species approach.

Mobile fishing gear reduces seafloor habitat complexity through the removal of struc- ture-building fauna, e.g. emergent organisms that create pits and burrows, as well as by smoothing of sedimentary bedforms (e.g. sand ripples). In this study, we compared the relative abundance of microhabitat features (the scale at which individual fish associate with seafloor habitat) inside and outside of a large fishery closed area (6917 km 2 ) on Georges Bank. Starting in late 1994, the closed area excluded all bottom tending fishing gear capable of capturing demersal fishes. A total of 32 stations were selected inside and outside of the closed area in sand habitats. Video and still photo- graphic transects were conducted at each station using the Seabed Observation and Sampling System (SEABOSS). Seven common (i.e. featureless sand, rippled sand, sand with emergent fauna, bare gravelly sand, gravelly sand with attached-erect fauna, whole shell, shell fragment) and 2 rare (sponges, biogenic depressions) microhabitat types were compared separately. Results showed sig- nificant differences in the relative abundance of the shell fragment and sponge microhabitat types between fished and unfished areas. The lack of differences for the other microhabitats may indicate that the level of fishing activity in the area is matched by the system's ability to recover.