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Misty Groupers (Hyporthodus mystacinus) are one of the largest and most geographically widespread grouper species and one of the few grouper species known to occur at depths greater than 200 m. However, aspects of their basic biology, behavior, and ecology remain poorly understood, leaving significant gaps in our ability to evaluate their functional role throughout the vertical water column, as well as our understanding of their conservation needs in a changing ocean. Through in-situ video observation obtained using deep-sea landers in both The Bahamas and Cayman Islands over multiple years, we documented Misty Grouper occurrence up to 470 m depth in the mesopelagic zone. These observations provide a new depth range extension for the species and illuminate the potential importance of deep-water habitats for large grouper species in the wider Caribbean. [ABSTRACT FROM AUTHOR]

Balanced ecosystems benefit meso and top predators, which help to maintain the quality of the habitat. Thus, the presence of sharks can be considered an indicator of environmental health. Baited remote underwater stereo-videos (BRUVs) were used to assess the relative abundance of sharks in the Alcatrazes Archipelago, Southwestern Atlantic, after an important no-take zone expansion from 12 to 675 km2 with the creation of the Wildlife Refuge and enhanced enforcement, comparing our findings with previous BRUV surveys. This study observed sharks in 16 (10.7%) of the 150 stereo-BRUV deployments and recorded seven species (Squalus cf. albicaudus, Carcharias taurus, Carcharhinus plumbeus, Carcharhinus falciformis, Rhizoprionodon porosus, Sphyrna lewini, and Sphyrna zygaena). These data, combined with the perception of frequent and experienced divers (management staff and diving operators) about the increase in shark sightings, suggest a recent positive effect of the no-take zone for these predators and a healthier ecosystem. Results also show that long-term monitoring and effective enforcement of the Alcatrazes Wildlife Refuge are crucial to maintain and enhance the positive effects in the area. [ABSTRACT FROM AUTHOR]

The use of underwater video techniques has expanded rapidly in ecological studies and is particularly desirable in protected areas since the method does not impact the habitat or remove fish. The Mediterranean Sea is a biodiversity hotspot under high anthropogenic pressure and consequently, non-destructive and non-extractive techniques for fish monitoring are advantageous. Here, we review 110 publications that used underwater video in fish-related studies in the Mediterranean basin. The most common technique used in the Mediterranean Sea was Remotely Operated Vehicles (ROV) (33%), followed by Remote Underwater Video (RUV) systems (20%), Diver Operated Video (DOV) systems (20%) and Baited Remote Underwater Video (BRUV) systems (19%). Approximately one third of the studies used an additional sampling method, such as fisheries-based or molecular methods with the aim to compare the surveying effectiveness or produce complementary data. The most frequent objectives of the reviewed studies were related to fish community structure, i.e., focusing on community wide metrics such as abundance and biodiversity, or behavioral analyses, while the most commonly studied environments were those of the western Mediterranean and shallow waters, usually involving sandy or rocky reef habitats. Sampling protocols differed widely among studies with transect lengths, soak times and baits all varying. Future research should focus on the least studied parts of the region, such as the eastern and southern Mediterranean Sea and deep-sea habitats. Finally, the development of standardized sampling protocols is recommended to ensure that data are comparable among studies. [ABSTRACT FROM AUTHOR]

New and innovative techniques utilizing underwater cameras have the potential to track changes in turtle populations whilst being less invasive and time intensive than traditional trapping surveys. In this study, we trialled the use of Baited Remote Underwater Videos (BRUVs) in five upland streams to test if BRUVs could be used for abundance, size and sex estimates of freshwater turtles. We also compared BRUVs to cathedral traps and identified key considerations for future use of this method, such as whether the time of day influenced results. Our study successfully detected 83 turtles from 52 h of footage and identified all species known to occur in the study area. The deployment time did not significantly influence relative abundance. BRUVs also produced statistically similar catch per unit effort estimates to cathedral trapping techniques. No small turtles (i.e. juveniles) were detected, and difficulties with visibility, sex accuracy and carapace measurements are discussed for future BRUV use. Our study shows that BRUVs are a useful, time effective, non‐invasive technique to collect relative abundance and species richness estimates for freshwater turtles. [ABSTRACT FROM AUTHOR]

The inaugural Computer Vision for Marine Scientists workshop was held at the 17th South African Marine Science Symposium, with the primary goal of establishing a community of practice for computer vision (CV) in marine sciences in South Africa. The one-day hybrid event, attended by 97 people, covered the principles of artificial intelligence (AI) techniques required for evaluating video and photographic imagery through presentations, practical demonstrations and interactive discussions. The recordings of the workshop sessions are available online, providing an opportunity to reach marine researchers both regionally and globally. The workshop highlighted that many scientists have begun to incorporate CV and AI into their research activities; however, there is little national coordination and the extent of research is lagging behind international trends. To support image-based AI research in South Africa, it is critical to maintain and expand the network established during the workshop. This would enable a more collaborative and successful approach to incorporating CV technology in the country's marine research initiatives, ultimately leading to ground-breaking discoveries and advancements in the field. [ABSTRACT FROM AUTHOR]

Context. Giant guitarfish (Family: Glaucostegidae) and wedgefish (Family: Rhinidae) (Critically Endangered, IUCN Red List and CITES Appendix II) are highly exploited throughout their distribution because of their highly valued fins in the international market. Both are commonly caught as bycatch or secondary valuable catch in the Java Sea, including in Karimunjawa National Park, Central Java, Indonesia. Aims. Assess the presence and relative abundance of giant guitarfish and wedgefish species in Karimunjawa National Park and adjacent waters. Methods. Data were collected using baited remote underwater video (BRUV) surveys across 40 sites, covering multiple zonation areas and depth ranges. All species were identified to the species level and their relative abundance was tested with one-way PERMANOVA based on sites, zonation areas and depths. Key results. Two target species, Glaucostegus typus and Rhynchobatus australiae, were present in the study area with a maximum number of 3 and 6 and relative abundance of 0.0048 and 0.0096 respectively, over 477 BRUVs and 623.9 h of videos. Their presence during the study was not affected by sites, zonations or depth. Implications. The presence and relative abundance of both G. typus and R. australiae were low, which may bea result of decades of overfishing, and have provided the first information to the urgency of managing the species in the areas. [ABSTRACT FROM AUTHOR]

Misty Groupers (Hyporthodus mystacinus) are one of the largest and most geographically widespread grouper species and one of the few grouper species known to occur at depths greater than 200 m. However, aspects of their basic biology, behavior, and ecology remain poorly understood, leaving significant gaps in our ability to evaluate their functional role throughout the vertical water column, as well as our understanding of their conservation needs in a changing ocean. Through in-situ video observation obtained using deep-sea landers in both The Bahamas and Cayman Islands over multiple years, we documented Misty Grouper occurrence up to 470 m depth in the mesopelagic zone. These observations provide a new depth range extension for the species and illuminate the potential importance of deep-water habitats for large grouper species in the wider Caribbean.

Bait-based remote underwater video (BRUV) systems are effective devices for remotely observing fish and other marine organisms in challenging environments. The development of a long duration (24 h) surface BRUV observation surveys allowed the monitoring of scarce and elusive pelagic sharks and the direct impact on non-targeted species of longline fishing in the Western Mediterranean. Technological limitations, such as the limited storage capacity and a single surface camera, were improved by (i) adding a deep camera equipped with light (below 80 m depth) and (ii) replacing Gopros with a multi-camera video surveillance system (surface and depth) with a storage capacity of several days and access to real-time observation. Based on a deployment effort of 1884 h video data, we identified 11 blue sharks (Prionace glauca) and one bluntnose sixgill shark (Hexanchus griseus), a deep-sea species that scarcely swims at the surface. The real-time observation capability was a powerful tool for reducing logistical costs and for raising environmental awareness in educational and outreach programmes. [ABSTRACT FROM AUTHOR]

The broadnose sevengill shark (Notorynchus cepedianus) is a large marine predator found in temperate coastal marine habitats. Despite being commonly encountered, details of its ecology are limited. To partially address this, we quantified the size and sex structure of N. cepedianus in Paterson Inlet, Stewart Island, New Zealand. A stereo-camera baited underwater video system (BRUV) was deployed in a shallow coastal embayment to capture underwater video of N. cepedianus for stereo photogrammetric measurement between June 2016 and November 2017. Individual sharks were sexed via observation of claspers. Three-dimensional underwater calibration of the photogrammetric system, using a precisely measured cube, indicated a mean error of <1%. Estimated total lengths ranged from 149.0 to 276.5 cm (n = 78 individuals, mean = 211.4, S.E. = 2.97). The observed sex ratio was heavily biased, with females making up 95% of the population in winter 2016 and 73% in summer 2017. This study provides new data on N. cepedianus in southern New Zealand as well a non-invasive, low-cost methodology that can be applied to other study areas. [ABSTRACT FROM AUTHOR]

Elasmobranch fishes (sharks, skates and rays) are some of the most morphologically and behaviourally diverse vertebrates on the planet, demonstrating a wide range of feeding strategies. The nurse shark (Ginglymostoma cirratum) is a large, widely distributed shark species which is commonly associated with tropical and subtropical reefs worldwide; yet it remains vastly understudied relative to other large species. To advance our understanding of nurse shark behaviour and ecology, we used opportunistic video observations gathered throughout the islands of Turks and Caicos from September 2020 to April 2021. We made 233 observations from 78 camera deployments and identified five behaviours, four of which were attributed to foraging. Stationary feeding behaviour was most commonly observed and strongly influenced by habitat type with a greater number of observations occurring on sand banks relative to reef habitat. Unique to this study was the first empirical description of pectoral positioning, by which individuals can position their body relative to a food-source through mobilization of the pectoral fins. We discuss these findings in relation to mechanical processes and kinematics, and the implications of expanding our knowledge of the functional role nurse sharks play in the transfer of energy across tropical seascapes. [ABSTRACT FROM AUTHOR]

Context: Remotely operated vehicles (ROVs) are routinely used to inspect oil and gas infrastructure for industry's operational purposes and scientists utilise this video footage to understand how fish interact with these structures. Aim: This study aims to clarify how fish abundance data obtained from ROV video compares to that collected using baited remote underwater video (BRUV). Method: This study compares fish assemblages observed using an industry ROV and BRUVs along a pipeline located in 130-m water depth in north-west Australia. Key results: Both methods recorded 22 species of fish, however each method observed 15 unique species. The fish assemblage recorded by each method was statistically different at all sites. Differences in the fish assemblages correlated with the caudal fin aspect ratio of each species: the mean caudal fin aspect ratio of fish recorded using BRUVs was 2.81, compared to 1.87 for ROV observations. Conclusions: We interpret this to indicate differences in site attachment, with site-attached species having generally lower caudal fin aspect ratios that are associated with slower swimming speeds with a burst and glide pattern. Implications: Our results show that these remote video methods predominantly sample different fish assemblages and demonstrates how different sampling methods can provide different insights into fish interactions with subsea infrastructure. Understanding the ecosystem around subsea oil and gas infrastructure is imperative to decommissioning. Our study found differences in fish assemblage data derived from industry remotely operated vehicle (ROV) video and baited remote underwater video (BRUV) collected along a subsea pipeline. Both methods sampled the same number of species, but ROV sampled more site attached species compared to BRUV. [ABSTRACT FROM AUTHOR]

Context: The inner Queen Charlotte Sound–Tōtaranui is a focal and emblematic coastal area in New Zealand that is valued by diverse stakeholders. Fish diversity in the region is not well characterised. Aims: This study sought to provide an inventory of local fish populations, determine the relative abundance of all species observed, and quantify fish biodiversity (including teleost, elasmobranch, syngnathid, chimaera, and cephalopod) in the region. Methods: Baited remote underwater video, a spatially balanced acceptance sampling design, and Bayesian spatio-temporal analysis approaches using integrated nested Laplace approximation (INLA) were employed. Key results: In total, 35 species were observed over 3 years. Average site-specific levels of species abundance were low (∼3) with only modest levels of biodiversity (Shannon–Wiener value = 0.65, Simpsons index = 0.51). On the basis of spatial residuals, greater species diversity was identified in western arms of the sound. Conclusions: These findings provide a useful insight into the biodiversity of fish in the region, and baseline information on the relative abundance of a variety of fish species. Implications: These findings characterise the contemporary status of fish populations in the inner Queen Charlotte Sound and present a useful framework for ongoing investigations of fish populations in this, and other, inshore marine environments. A balanced survey design and baited camera systems were used to monitor the abundance and diversity of finfish in the inner Queen Charlotte Sound, New Zealand. With seasonal observations conducted over 3 years, study outputs provide the first quantification of finfish relative abundance and biodiversity in this highly valued marine environment. [ABSTRACT FROM AUTHOR]

Bait-based remote underwater video (BRUV) systems are effective devices for remotely observing fish and other marine organisms in challenging environments. The development of a long duration (24 h) surface BRUV observation surveys allowed the monitoring of scarce and elusive pelagic sharks and the direct impact on non-targeted species of longline fishing in the Western Mediterranean. Technological limitations, such as the limited storage capacity and a single surface camera, were improved by (i) adding a deep camera equipped with light (below 80 m depth) and (ii) replacing Gopros with a multi-camera video surveillance system (surface and depth) with a storage capacity of several days and access to real-time observation. Based on a deployment effort of 1884 h video data, we identified 11 blue sharks (Prionace glauca) and one bluntnose sixgill shark (Hexanchus griseus), a deep-sea species that scarcely swims at the surface. The real-time observation capability was a powerful tool for reducing logistical costs and for raising environmental awareness in educational and outreach programmes.

Evaluating effectiveness of marine No-take Zones (NTZ) can be cost or labor prohibitive, thus comparisons to nearby unprotected areas are typically lacking. Two NTZs were evaluated, the waters surrounding Ilha Anchieta State Park and Palmas Island in Ubatuba, São Paulo, Brazil, for species richness, diversity, and abundance of ichthyofauna, comparing them with two nearby unprotected “Take” Zones. From 23 deployments using Baited Remote Underwater Video (BRUV), 737 individuals from 51 species of fish were recorded. The NTZ community composition was significantly different from Take Zones, with higher average species richness, abundance, and diversity but similar evenness. Seven species, accounting for more than 72% of the composition differences between Take and NTZs, were more abundant in NTZs. Comparisons of individual sites within each zone showed high variability for the Mar Virado Take Zone, with one site grouped with NTZs at 30% similarity. In parallel, BRUV deployed over a short period was assessed as a potential rapid, low-cost method for analyzing the effectiveness of a marine protected area, important for management of sites in low- and middle-income countries with patchy resource availability. BRUV distinguished significant community structure differences between Take and NTZs, with no difference between sites within each classification. Comparing with BRUV conducted for a longer period at two of the four study sites (MV and PA), our rapid study recorded 44.3% of total species using 28% of the survey effort. Compared with a multi-method survey as a proxy for a record of all potential species present at a third site (AI), BRUV recorded 30% of total species using 4.2% of the survey effort. BRUV showed bias towards size classes >15cm and certain feeding strategies, important to note if assessing a single target species. Overall, this rapid implementation of BRUV showed a clear difference between sites that differed in fishing protection level.

In the Southwest Atlantic, fisheries and in situ observations suggest that mesophotic reefs occur further south than has been reported in the literature, and a description of these subtropical regions is still lacking. We used Baited Remote Underwater stereo-Videos to explore unrevealed patterns in the vertical structure of fish assemblages on subtropical Atlantic reefs, contrasting shallow and mesophotic habitats. Our data on species turnover and light penetration reveal that in the subtropical Atlantic, the boundaries between shallow and mesophotic habitats occur at depths of 18 m, which is shallower than most previous studies have shown. Generalized additive mixed models identified different environmental and management factors as important predictor variables that explain distribution of fish assemblages' attributes. Besides adding new evidence about mesophotic limits, we described variations in the vertical structure of fish assemblages, providing important information for the description and conservation of mesophotic environments in subtropical regions. [Display omitted] • Light penetration and species turnover determine boundaries of mesophotic ecosystems. • Shallow and mesophotic zones shelter different species richness and abundance. • Subtropical mesophotic zones do not provide refuge for fishery target species. • Environmental and management factors act in synergy shaping fish assemblages. [ABSTRACT FROM AUTHOR]

More than half of the fish biomass of coastal rocky reefs depends on zooplankton; however, the trophic basis of estuarine fish assemblages remains unknown. We quantified the trophic basis (i.e. basal energy sources) of fish community biomass inhabiting three habitat types (seagrass, natural reef and artificial reef) in two estuaries, compared with two coastal rocky reef sites. Fish assemblages were surveyed with Baited Remote Underwater Video (BRUVs) and the species abundance, richness and biomass of fish were classified into nine functional feeding groups (6 teleost and 3 elasmobranch). Comparable metrics for coastal fish assemblages were obtained from published surveys using BRUVs. Using the functional feeding group biomass and the group-specific diet composition, the breakdown of energy sources was calculated using a food web analysis. Estuarine reef habitats had different species and different functional feeding group composition than seagrass habitat. The majority of fish biomass in the seagrass habitat was supported by detritus (51% in Botany Bay) or macrophytes (58% in Lake Macquarie). In contrast, zooplankton supported most fish biomass (45–59%) at the coastal reef locations, and in reef habitat in one estuary (35–43%), but not the other estuary (33–34%). Trophic pathways which support fish assemblages, are key in identifying mitigation measures which can help conserve these populations with growing urbanisation of estuaries and coasts. [ABSTRACT FROM AUTHOR]

Evaluating effectiveness of marine No-take Zones (NTZ) can be cost or labor prohibitive, thus comparisons to nearby unprotected areas are typically lacking. Two NTZs were evaluated, the waters surrounding Ilha Anchieta State Park and Palmas Island in Ubatuba, São Paulo, Brazil, for species richness, diversity, and abundance of ichthyofauna, comparing them with two nearby unprotected "Take" Zones. From 23 deployments using Baited Remote Underwater Video (BRUV), 737 individuals from 51 species of fish were recorded. The NTZ community composition was significantly different from Take Zones, with higher average species richness, abundance, and diversity but similar evenness. Seven species, accounting for more than 72% of the composition differences between Take and NTZs, were more abundant in NTZs. Comparisons of individual sites within each zone showed high variability for the Mar Virado Take Zone, with one site grouped with NTZs at 30% similarity. In parallel, BRUV deployed over a short period was assessed as a potential rapid, low-cost method for analyzing the effectiveness of a marine protected area, important for management of sites in low- and middle-income countries with patchy resource availability. BRUV distinguished significant community structure differences between Take and NTZs, with no difference between sites within each classification. Comparing with BRUV conducted for a longer period at two of the four study sites (MV and PA), our rapid study recorded 44.3% of total species using 28% of the survey effort. Compared with a multi-method survey as a proxy for a record of all potential species present at a third site (AI), BRUV recorded 30% of total species using 4.2% of the survey effort. BRUV showed bias towards size classes >15cm and certain feeding strategies, important to note if assessing a single target species. Overall, this rapid implementation of BRUV showed a clear difference between sites that differed in fishing protection level. [ABSTRACT FROM AUTHOR]

Freshwater crayfish are among the most endangered animal groups in the world. Appropriate management requires an understanding of sampling bias when assessing their distribution and abundance. We evaluated the effectiveness of a variety of sampling methods for detecting freshwater crayfish (genus Euastacus) in situ and potential biases towards individual-level traits associated with these methods. We also experimentally manipulated the presence of crayfish within opera house traps to determine the effects of trap residency on capture rate and the characteristics of crayfish approaching the traps. Baited hoop nets and baited remote underwater video surveys (BRUVS) detected significantly more crayfish than did unbaited video surveys (RUVS). Crayfish captured in baited hoop nets were significantly larger than were crayfish measured in the BRUV and RUV surveys, suggesting that hoop nets were biased to capturing larger animals. The experiment demonstrated that a greater number of crayfish entered empty rather than occupied traps; however, there were no differences in their body sizes. We highlight the importance of optimising sampling for freshwater crayfish to ensure reliable and robust population estimates. This is of critical importance as many have highly restricted ranges and face numerous threats. We contend that this will assist in informing conservation strategies to protect aquatic species at risk. Freshwater crayfish are among the most endangered animal groups in the world. We examined bias associated with baited traps for members of this diverse group in Australia. We confirmed that traps predominantly captured large males, whereas their abundance was underestimated two- to three-fold when compared with that from baited video surveys. Animals avoided traps with a captive crayfish. Video techniques can better inform conservation efforts. [ABSTRACT FROM AUTHOR]

Marine reserves are an important management tool for conserving local biodiversity and protecting fragile ecosystems such as seagrass that provide significant ecological functions and services to people and the marine environment. With humans placing ever-growing pressure on seagrass habitats, marine reserves also provide an important reference from which changes to seagrass and their ecological assemblages may be assessed. After eight years of protection of seagrass beds (Posidonia australis) in no-take marine reserves (Sanctuary Zones) within the Jervis Bay Marine Park (New South Wales, Australia; zoned in 2002), we aimed to assess what changes may have occurred and assess continuing change through time in fish assemblages within these seagrass meadows. Using baited remote underwater videos (BRUVs), we sampled seagrass fish assemblages at three locations in no-take zones and five locations in fished zones three times from 2010 to 2013. Overall, we observed a total of 2615 individuals from 40 fish species drawn from 24 families. We detected no differences in total fish abundance, diversity, or assemblage composition between management zones, although we observed a significant increase in Haletta semifasciata, a locally targeted fish species, in no-take marine reserves compared with fished areas. Fish assemblages in seagrass varied greatly amongst times and locations. Several species varied in relative abundance greatly over months and years, whilst others had consistently greater relative abundances at specific locations. We discuss the potential utility of marine reserves covering seagrass habitats and the value of baseline data from which future changes to seagrass fish populations may be measured.

Tidal wetlands represent important fish habitats, particularly as nurseries for many exploited species. However, usage of these habitats by large-bodied fish is poorly studied. Imaging sonar represents a relatively novel technology for ecologists and allows for the discrete observation of fish in conditions where a light-based camera is ineffective, such as turbid estuarine habitats. An imaging sonar uses sound waves to create video-like images where swimming direction, fish length and distance from the sonar can be inferred. This technology was applied to examine connectivity of large-bodied fish between a recovering Ramsar-listed wetland and the adjacent estuary, by censusing fish traversing the entrance to the wetland. Fish lengths ranged between ~ 8 and 109 cm. More fish were observed traversing the entrance to the wetland during the day (~ 365 fish h−1) compared with night (~ 198 fish h−1), possibly as a predator avoidance strategy. Under some conditions, biomass flux of large-bodied fish was estimated to exceed 100 kg fish h−1. Fish did not appear to have a consistent preference for moving with or against the flow of the tide. These novel findings highlight the utility of imaging sonar for conducting fish census in wetland habitats and also highlights that wetlands are valuable habitats for large-bodied fish. [ABSTRACT FROM AUTHOR]

Shallow coastal lagoons are vital ecosystems for many aquatic species and understanding their biodiversity is essential. Very little is known about the distribution and abundance of globally threatened marine megafauna in coastal lagoons of the Arabian Gulf. This study combined underwater and aerial surveys to investigate the distributions and relative abundance of marine megafauna in a large lagoon. We identified 13 species of megafauna including sea turtles, sharks, and rays. Eleven of these are globally threatened according to the IUCN Red List of Threatened Species. The Critically Endangered Halavi guitarfish (Glaucostegus halavi), and the Endangered green turtle (Chelonia mydas) were the most frequently occurring species. Results demonstrate the value of combining aerial and underwater video surveys to obtain spatially comprehensive data on marine megafauna in shallow coastal lagoons. This new information emphasises the importance of Umm Al Quwain lagoon for biodiversity conservation to protect threatened marine species and their habitats. • Coastal lagoons of the Arabian Gulf host globally threatened marine megafauna. • We combined aerial and underwater surveys to investigate megafauna. • We identified 13 species of megafauna, including sea turtles, sharks, and rays. • Threatened Halavi guitarfish and green turtles were the most abundant. • Key information to support conservation actions in UAE coastal lagoons [ABSTRACT FROM AUTHOR]

The Critically Endangered shorttail nurse shark Pseudoginglymostoma brevicaudatum (Günther, 1866) is a small-bodied Orectolobiform shark found only in the Western Indian Ocean (WIO). We report here on a significant range extension for P. brevicaudatum based on four records of the species in southern Mozambique, recorded during research surveys, including a specimen collected in 1967 and video surveys in 2019, and opportunistic assessments of shore-angler photographic catch records. These are the first records of P. brevicaudatum in Mozambique. The potential factors for this range extension and its implications for the management of this species are discussed. We also present morphological descriptions of the first recorded P. brevicaudatum specimen from Mozambique and of the dentition of this species (based on samples from Madagascar), and comment on the current status of knowledge and knowledge gaps for this species. Owing to its poor conservation status, limited inshore distribution and potential and confirmed fishery threats, improved knowledge and conservation should be considered priorities for P. brevicaudatum. [ABSTRACT FROM AUTHOR]

The Islas Marías Biosphere Reserve, made up of 4 islands in Pacific waters off central Mexico, supports a large diversity of marine life. However, scientific research was restricted for decades by the occupation of Isla María Madre by the Federal Penitentiary Colony of Mexico from 1905 to 2019. Aside from a list of coastal fish species published in 2011, little has been published about the fish biodiversity in the area. While the limited access to the archipelago may have acted as a de-facto marine reserve, there is evidence that fishing continued both legally for the benefit of the colony and illegally by trespassing vessels. In order to establish baseline ecological data for future conservation planning, we used baited remote underwater video (BRUV) surveys at all 4 islands during 3 expeditions to the archipelago in 2018. A total of 131 BRUV surveys representing ~150 h of footage were analyzed to create the most current compilation of species and abundance data on coastal marine fishes at Islas Marías. Ninety-nine species were identified, 3 of which were additions to the previous assessment. We found strong separation of fish communities based on both habitat and depth, and an association between hard-bottom habitats and high biodiversity of reef fishes. With the declaration of Islas Marías as a natural reserve and relocation of the prison in 2019, there is an opportunity for the reserve to become a priority area for marine conservation on the Pacific coast of Mexico. Spatial analyses of fish biodiversity at Isla María Cleofas can help develop sustainable management strategies at a time when the governmental jurisdiction of the iconic archipelago is uncertain.

Artificial reef communities undergo long periods of succession prior to becoming stable, but funding challenges often prevent post-deployment monitoring from evaluating long-term successional changes. The present study employed baited remote underwater video surveillance (BRUVS) to compare the species richness, diversity, abundance, and age structure of fishes across a 4-year-old artificial reef, a 41-year-old artificial reef, a representative natural reef, and a bare control in Nantucket Sound, MA, USA, to address whether the perceived success of an artificial reef can be determined 5 years after deployment. Results indicated that, while species richness and diversity were largely uniform throughout the Sound, fish appeared on camera 93.4% faster at artificial reef sites than they did at the bare sand control. Reef-associated fish were 103.7% more abundant on the older artificial reef than on the younger artificial reef. Therefore, although the younger artificial reef is in its fifth year of monitoring, abundances of economically important fishes on the reef may continue to increase in future years and current numbers may not accurately reflect reef success or failure. Future management plans should consider extending monitoring programs longer than 5 years and implementing temporal fishing closures on newly deployed reefs to facilitate earlier post-deployment community stabilization. [ABSTRACT FROM AUTHOR]

The Islas Marías Biosphere Reserve, made up of 4 islands in Pacific waters off central Mexico, supports a large diversity of marine life. However, scientific research was restricted for decades by the occupation of Isla María Madre by the Federal Penitentiary Colony of Mexico from 1905 to 2019. Aside from a list of coastal fish species published in 2011, little has been published about the fish biodiversity in the area. While the limited access to the archipelago may have acted as a de-facto marine reserve, there is evidence that fishing continued both legally for the benefit of the colony and illegally by trespassing vessels. In order to establish baseline ecological data for future conservation planning, we used baited remote underwater video (BRUV) surveys at all 4 islands during 3 expeditions to the archipelago in 2018. A total of 131 BRUV surveys representing ~150 h of footage were analyzed to create the most current compilation of species and abundance data on coastal marine fishes at Islas Marías. Ninety-nine species were identified, 3 of which were additions to the previous assessment. We found strong separation of fish communities based on both habitat and depth, and an association between hard-bottom habitats and high biodiversity of reef fishes. With the declaration of Islas Marías as a natural reserve and relocation of the prison in 2019, there is an opportunity for the reserve to become a priority area for marine conservation on the Pacific coast of Mexico. Spatial analyses of fish biodiversity at Isla María Cleofas can help develop sustainable management strategies at a time when the governmental jurisdiction of the iconic archipelago is uncertain. [ABSTRACT FROM AUTHOR]

Behavioral interactions such as dominance are critical components of animal social lives, competitive abilities, and resulting distribution patterns with coexisting species. Strong interference competition can drive habitat separation, but less is known of the role of interference if agonistic interactions are weak. While most theoretical models assume interference abilities to be constant in an environment, few consider that the extent of interference can vary by habitat and change model predictions. Using baited underwater cameras, we show a consistent dominance status between two sympatric reef sharks at an uninhabited Pacific atoll. Blacktip reef shark (Carcharhinus melanopterus) and gray reef shark (Carcharhinus amblyrhyncos) relative abundance showed an inverse relationship to each other but the strength of this relationship varied by habitat. Reef shark relative abundance declined more rapidly in the presence of heterospecifics on forereef habitats as opposed to backreefs. In all habitats, gray reef sharks were more likely to bite bait cages than blacktips when both species were present, and appeared to be the dominant species. Intraspecific interactions were also apparent, with individual willingness to bite bait decreasing as the number of conspecifics increased. Gray reef sharks may exert differential control over blacktip foraging success in different habitats. Habitat-specific behavioral interactions may partially explain patterns of spatial separation between competing species where interference is weak. [ABSTRACT FROM AUTHOR]

In situ observation of Antarctic toothfish (Dissostichus mawsoni) is challenging as they typically live at depths greater than 500 m, in dark and ice-covered Antarctic waters. Searching for adequate methodologies to survey Antarctic toothfish in their habitat, we tested a miniaturized Baited Remote Underwater Video camera (BRUV), deployed through holes drilled in the sea ice in the Ross Sea region, over three field seasons. In 2015 three BRUVs were deployed at McMurdo Sound, and paired with a vertical longline sampling. In 2017, three opportunistic deployments were performed at Terra Nova Bay. In 2018 seven deployments at Terra Nova Bay provided preliminary data on the habitat preferences of the species. The design and configuration of the mini-BRUV allowed to collect high-quality video imagery of 60 Antarctic toothfish in 13 deployments from the fast sea ice. The behaviour of fish at the bait, intra-species interactions, and potential biases in individual counting were investigated, setting baselines for future studies on the abundance and distribution of Antarctic toothfish in sea-ice covered areas. This work represents the first step towards the development of protocols for non-extractive monitoring of the Antarctic toothfish in the high-Antarctica coastal shelf areas, of great value in the Ross Sea region where the largest MPA of the world has recently been established.

Enhanced survey efforts in the Arctic are currently needed to broaden our understanding of marine species distributions and establish the baseline data and methodologies necessary to detect potential responses to changing regional climate and human activities. For the first time, a baited remote underwater video (BRUV) survey was conducted in the Eastern Canadian Arctic, providing new biological information within data-poor regions of interest for marine conservation and potential fisheries development. A total of 31 camera deployments were conducted in 2015–2016 aboard an industry fishing vessel during summer exploratory fishing cruises, with observations occurring in the marine waters of the Qikiqtaaluk (Baffin) Region of Nunavut. In total, 18 invertebrate taxa and 14 fish taxa were observed at the baited camera, with significant differences in assemblages among sites associated with spatial variation in temperature and depth. The Greenland shark Somniosus microcephalus and polar cod Boreogadus saida were the dominant fish species observed, with the presence of brittle stars Ophiuroidea, amphipods and chaetognaths dominating invertebrate communities. Comparisons with concurrent fisheries catch data (whelk pots) demonstrated the baited camera's ability to comparably detect local fish taxa when deployed over uniform, fine-grain sediment substrates, while local invertebrate assemblages were often better captured by fisheries surveys. These results illustrate the potential of low-impact BRUV survey methods to efficiently provide baseline data on spatial patterns of diversity and their drivers to advance our understanding of marine ecosystems within understudied polar regions. [ABSTRACT FROM AUTHOR]

Detecting the effects of introduced artificial structures on the marine environment relies upon research and monitoring programs that can provide baseline data and the necessary statistical power to detect biological and/or ecological change over relevant spatial and temporal scales. Here we report on, and assess the use of, Baited Remote Underwater Video (BRUV) systems as a technique to monitor diversity, abundance and assemblage composition data to evaluate the effects of marine renewable energy infrastructure on mobile epi-benthic species. The results from our five-year study at a wave energy development facility demonstrate how annual natural variation (time) and survey design (spatial scale and power) are important factors in the ability to robustly detect change in common ecological metrics of benthic and bentho-pelagic ecosystems of the northeast Atlantic. BRUV systems demonstrate their capacity for use in temperate, high energy marine environments, but also how weather, logistical and technical issues require increased sampling effort to ensure statistical power to detect relevant change is achieved. These factors require consideration within environmental impact assessments if such survey methods are to identify and contribute towards the management of potential positive or negative effects on benthic systems. • Annual variation and survey design impact the ability to detect change in ecological metrics. • Redundancy in sampling effort is important to ensure statistical power in environmental impact assessments • Baited underwater video (BRUV) systems demonstrate their capacity for use in temperate, high energy marine environments. [ABSTRACT FROM AUTHOR]

A new record of the neotropical otter (Lontra longicaudis) in the marine environment near the rocky reef of a coastal island in Brazil is described here, being the first published report of a semi-aquatic mammal by baited remote underwater video system. This species is not usually sighted in marine waters away from the mainland coast, and it has never been reported in this environment in this region. This individual may have increased its feeding grounds further offshore as food resources close to the mainland are reduced. Baited videos present a relatively low cost option to understand better these animals existing in different habitats, improving the monitoring for these species and providing valuable information on their distribution, habitat use, and life history. [ABSTRACT FROM AUTHOR]

Using a baited remote underwater video system (BRUV), we provide the first recorded in situ observation of the sharpnose sevengill shark, Heptranchias perlo (Bonnaterre, 1788), from the Tongue of the Ocean, Bahamas. The individual was recorded at a depth of 718 meters, allowing for visual analysis of behavior in its natural environment. Temperature recordings of about 9° C at this depth indicate that H. perlo is physiologically capable of thriving within the lower mesophotic zone. This observation underscores the need to conduct further explorations of elasmobranch diversity and distribution in the Bahamas, which can be readily facilitated by BRUV-based methods. [ABSTRACT FROM AUTHOR]

Marine Protected Areas (MPAs) are known to contribute toward the conservation of marine biodiversity, particularly targeted fishery species. Snapper Chrysophrys auratus are an important recreational and commercial fish species in New South Wales (NSW), Australia, and despite fishery management for this species, they are considered “growth overfished” in this region. To assess how C. auratus respond to the implementation of an MPA with several no-take and partially protected areas in temperate NSW, we monitored their populations over a decade (2006–2017) using baited remote underwater video systems (BRUVs). Surveys were conducted in the Port Stephens-Great Lakes Marine Park with BRUVs deployed on rocky reefs in depths of 20–50 m. Long term seasonal sampling (winter vs. summer) was undertaken at two locations (Broughton and Fingal Island), and changes in C. auratus abundance prior to, and 8 years after zoning implementation, were assessed between these two locations. In total, we sampled five no-take areas within the marine park and five comparative nearby partially protected fished areas and three sites located outside the marine park boundaries. The most pronounced changes in abundance and size structure for C. auratus were observed in the Broughton Island no-take area where numbers increased almost 3-fold (2.91 times) over 8 years of protection. Relative abundance showed seasonal variation at two locations, and we consistently recorded increasing abundance within no-take areas at Broughton and Fingal Island compared to nearby sites open to fishing. Surveys across the five no-take areas found a significant increase in the abundance of C. auratus, whilst the five partially-protected locations in the marine park still recorded higher abundances than sites outside the marine park. In addition, length measurements from stereo-BRUVS indicated that C. auratus were significantly larger in no-take areas compared to partially-protected areas in the marine park and sites outside the marine park. This study demonstrates how the implementation of the marine park and the protection afforded by no-take and partially-protected areas provides refuge for this important fishery targeted species.

Dependence on seafood across Southeast Asia is extensive. Myanmar is no exception, but the country's provisioning marine ecosystems are threatened. Seagrass is one habitat that is frequently overlooked in management as an important fisheries resource, despite its nursery function. In Myanmar, research on seagrass habitats is particularly sparse, and as a result, our understanding of seagrass exploitation remains limited. In this study, we provide a baseline assessment of the seagrass-associated fish assemblages at four locations in the Myeik Archipelago in southern Myanmar using mono Baited Remote Underwater Video systems. Across the sites surveyed only 12 taxa of motile fauna were recorded. Relative to other regional and global studies, this figure is meagre. Our data adds to a growing literature suggesting that the marine ecosystems of Myanmar are in a worrying state. Despite the lack of recorded seagrass associated fauna, our study revealed minimal impacts to seagrass meadows from eutrophication or sedimentation, and the meadows included appeared to be healthy. The sites with the highest number of motile fauna were within Myanmar's only National Marine Park offering some optimism for the effectiveness of protection, but further assessments are required to allow targeted management of Myanmar's seagrass meadows. [ABSTRACT FROM AUTHOR]

Aim We used modelled environmental data to identify important drivers of bioregional patterns of demersal fish assemblages characterized by a high proportion of endemic species. Location Of 1,600 km of coastal marine environment in south-western Australia. Methods We compiled data from 1090 stereo- BRUVs samples; a total of ~55,000 individuals belonging to 219 demersal fish species. Multivariate Regression Trees and Distance-based Linear Models distinguished which biological and/or environmental variables, amongst an initial set of 49, were most correlated to observed patterns of demersal fish assemblage structure. Indicator species analysis identified fish species most representative of the assemblage types. Results The most parsimonious model (constrained by five benthic variables and one spatial variable) explained 42% of the variation in spatial patterns of fish community structure. Canopy-forming seaweeds were the major benthic drivers, and, when found on structurally complex hard habitat, supported the highest diversity of species after sites dominated by hard coral cover. Indicator species analysis revealed that 28 of 35 significant species for this habitat type were endemics with fish assemblages associated with these habitats often spatially restricted to tens of kilometres. Main conclusions Demersal fish assemblage composition and biogeographical ranges in south-western Australia are strongly influenced by the presence of canopy-forming macroalgae. Canopy-dominated habitats have already been subject to catastrophic temperature-related die-offs in the northern part of this study, indicating its vulnerability to temperature-driven climate change. These results highlight not only the crucial role of this habitat in supporting endemic fish communities in the region, and the tenuous nature of their existence, but also the challenges facing marine managers who, unable to manipulate the influence of climate change variables, can only focus on alleviating stresses operating on local scales. [ABSTRACT FROM AUTHOR]

The use of baited remote underwater video to remotely observe fish and generate indices of relative abundance has steadily gained acceptance as a fisheries management tool particularly as survey time series have matured. Because ‘capture’ for this gear is visually derived, fish can possibly be counted multiple times and therefore different methods of estimating site abundances have been developed. We compared the performance of two video abundance estimation techniques, MaxN and MeanCount, by generating relative indices of abundance using a delta lognormal model. We demonstrated high correspondence between standardized indices produced through the years analyzed independent of the species evaluated, indicating there was little change in the information content between indices. Despite the agreement between the indices, estimates for proportion positive and coefficient of variation (CV) showed a general reduction in precision when using the MeanCount method for all species analyzed. Systematic underestimation of proportion positives and high CV values generated using MeanCount is problematic for the use of that abundance estimation method. Individual-based modeling results confirmed that MeanCount is linearly related to true abundance, while MaxN showed a power relationship. However, the MaxN estimate became linear as the area observed was increased in the model from 25% to 100%, which suggests that syncing cameras and generating counts over the entire observed area would eliminate the asymptotic relationship and simplify the use of MaxN estimators. Better understanding of catchability for optical type gears would enhance understanding of the relationship between the generated index and true population abundance, and supply assessment scientist with a clearer understanding of how to incorporate these types of survey data into assessments. [ABSTRACT FROM AUTHOR]

Artificial reefs are a popular fisheries management tool, but the effect of these reefs on the abundance of fish in the surrounding pelagic environment is uncertain. Pelagic baited remote underwater video (PBRUV) was used to observe the fish assemblage surrounding an offshore artificial reef (OAR), near Sydney, Australia. PBRUVs were deployed at three distances (30, 100, 500 m) from the OAR, and compared with a drop camera deployed directly over the OAR. There was a significantly greater abundance of fish on the OAR, but no significant difference in abundance at the 30-, 100- or 500-m distances. Two highly mobile non-resident species (Seriola lalandi, Pseudocaranx dentex) were significantly more abundant on the OAR, but this association was not detected 30 m away. The lack of a significant difference in total fish abundance, or in assemblage composition, between the 30-, 100- and 500-m distances suggests that any association with the OAR is on a localised scale (<30 m). One exception was the ocean leatherjacket (Nelusetta ayraudi), which had an association detected 100 m from the OAR. This predominantly small-scale effect may be influenced by the proximity of this OAR to numerous natural reefs. Underwater video was used to observe the fish assemblage surrounding an offshore artificial reef, in Sydney, Australia. We found up to 10 times more fish on the reef itself than at 30, 100 and 500 m from the reef. This suggests that artificial reefs are very effective at increasing fish abundance, but generally act on a localised scale (<30 m). [ABSTRACT FROM AUTHOR]

To overcome anthropogenic impacts which have reduced fisheries productivity due to habitat limitations, artificial reefs have been deployed in increasing numbers throughout the world. A significant body of research has been undertaken to evaluate the response of fish assemblages to reef deployments, however the majority of these studies only cover the first year post-deployment. The few studies spanning 10 years or more suggest these time frames are required to properly document the performance of artificial reefs. We monitored artificial reefs, deployed to enhance recreational fisheries, over two time periods separated by 10 years, with each period lasting two years. In the first two years the fish assemblage on artificial reefs was distinct to those on nearby natural reefs, with this pattern found to remain consistent after 10 years. Recreationally important species were recorded during the first two years, however the abundances of some increased after 10 years and additional species targeted by anglers were only observed during the latter sampling period. No decline in the abundances of recreationally important species were recorded after 10 years. Despite a lack of convergence with fish assemblages at natural reefs, the artificial reefs continued to meet their pre-deployment goals of enhancing local recreational fisheries. [ABSTRACT FROM AUTHOR]

We report on still/video photographic studies in 2018/9 of diurnal and nocturnal benthic scavenging on carrion in shallow water (2 m and 12 m depths) within Lough Hyne (a biodiverse Irish sea lough) using natural light during replicated 6 h daytime deployments and dim red light (630 nm) during 6 h deployments at night. In 2018 at 2 m depth in the North Basin, bait was present throughout day-time deployments, showing little evidence of scavenging; scavenger species' richness and abundance were low. At night, baits disappeared or were skeletonised; they were scavenged by a significantly more abundant and species-rich scavenger guild. At 12 m depth in the same basin, baits were removed or skeletonised during day and night. This confirmed our hypothesis that scavengers avoid well-lit very shallow water during the day, probably to avoid predation. Multivariate analysis of 2018/19 still photo data (12 m depth) revealed pronounced and statistically significant separate clustering of day, night and basin abundance/species data, although overall species' richness values did not differ significantly. These analyses together reflected differences in species' compositions associated with contrasting sediments, flow regimes and night/day. Nephrop s norvegicus , Pagurus bernhardus and Crangon crangon were only found in the low flow rate North Basin; Homarus gammarus , Trigla sp., Callionymus lyra, Agonus, Tritia reticulata and Marthasterias glacialis were only found in the high flow rate South Basin. Most scavenger species foraged in both day and night (though in different proportions). However, prawns (Palaemon serratus) only appeared at night. Small mobile scavenging fish, small crabs and prawns arrived at baits within seconds to minutes, as did locally-abundant slow movers (e.g. anemones (Anthopleura ballii), whelks (T. reticulata)). These times are shorter than recorded in earlier studies in deeper water. Larger crustaceans (e.g. Cancer pagurus , H. gammarus) took tens of minutes to hours before arrival; similar times have previously been recorded in deeper water. Large crustacean scavengers (C. pagurus, Maja squinado, H. gammarus) took substantial quantities of bait during long feeding bouts, but catsharks (Scyliorhinus canicula) often took similar quantities in a few seconds. All of the dominant scavenger species are broad-spectrum omnivores; only one obligate scavenger species (Tritia reticulata) was present (only in South Basin) and consumed negligible quantities of bait. • Dim red illumination permitted effective study of nocturnal marine scavenging. • Night-time scavenging was much more intense and species-rich than in day-time at 2 m depth. • Scavenger communities varied geographically and temporally. • Prawns Palaemon serratus only scavenged at night but were effective bait macerators. • Crustacea spent long periods feeding on bait; fish, including catsharks fed for seconds at a time. [ABSTRACT FROM AUTHOR]