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Aerial drone technology can assist compliance of trap fisheries
Abstract
Illegal fishing is a global issue that threatens the viability of fishing industries and biodiversity conservation. Management agencies typically use on‐ground surveillance to monitor and minimise illegal fishing practices, the efficacy of which may be enhanced by integrating emerging remote sensing technology. Affordable drones may contribute to cost‐effective detection of illegal fishing activity and associated gear, although their application has yet to be evaluated in many types of fisheries. Here, the utility of drones for the detection of crab traps and floats set in a shallow estuary was quantitatively tested, and the effects of survey altitudes, cameras and monitor screens on detection rates were determined. It was found that drone flight altitude and float colour influenced the detection rates of common crab trap floats, with infrared cameras improving the detection of floats camouflaged by black paint. However, the type of monitor screen used by the drone operator had no influence on the detection of crab traps. Overall, it appears drones can contribute to cost‐effective compliance in estuarine trap fisheries, and the approach can contribute to evidence‐based standard operating procedures.
... Technological improvements to drones have decreased the costs and improved the capacity for collecting high-quality data that can underpin management decisions in coastal environments (Provost et al., 2019). Presently, drones have been used effectively to detect abandoned and lost fishing gear (Bloom et al., 2019;Provost et al., 2020), improve protected area monitoring and surveillance (Jiménez López & Mulero-Pázmány, 2019;Toonen & Bush, 2018) and stock assessments (Groves et al., 2016;, as well as documenting large marine fauna and potentially dangerous sharks in nearshore areas Colefax et al., 2020). Additionally, the use of drone-based methods can improve results compared to established techniques, through more accurate counts of focal species (Hodgson et al., 2018), increased coverage in challenging habitats (Konar & Iken, 2018) Given the growing success of drones for supporting coastal management, they may also provide a cost-effective solution for collecting data on recreational fishing participation. ...
... Additionally, boat-based fishers may be unobservable by aerial survey techniques when angling from vessels with full cabins, hard roofs or Bimini tops. The complimentary use of drones within fisheries management may be the optimal use of this Chapter 5. Assessing the viability of small aerial drones to quantify recreational fishers Improving management and compliance of coastal areas with cost-effective drone surveillance 79 technology, such as the rapid detection of passive fishing gear (Provost et al., 2020) or for assessing stocks to determine the effect of management decisions (Beckmann et al., 2019). ...
... Provost, E. J.,Butcher, P. A., Coleman, M. A., Bloom, D., & Kelaher, B. P. (2020). Aerial drone technology can assist compliance of trap fisheries. ...
... Using UAV remote sensing, researchers can effectively monitor and manage human activities in protected areas (Jiménez López and Mulero-Pázmány, 2019) and effectively protect threatened species (e.g., monitor and track illegal vessels to reduce potential threats to marine animals) (Arefin, 2018). Its efficient aerial survey capabilities can also effectively monitor and supervise the enforcement of illegal operations (Bloom et al., 2019;Provost et al., 2020a) and collect data on recreational fisheries (Desfosses et al., 2019;Provost et al., 2020b) to facilitate enforcement at sea. The identification of fish aggregations (Vanderlaan et al., 2014), spawning locations (Harrison et al., 2020), and critical nursery habitats (Harris et al., 2019;Ventura et al., 2016) to monitor illegal fishing activities (Provost et al., 2020a) also confirms the ideal role of UAV remote sensing in fisheries regulation. ...
... Its efficient aerial survey capabilities can also effectively monitor and supervise the enforcement of illegal operations (Bloom et al., 2019;Provost et al., 2020a) and collect data on recreational fisheries (Desfosses et al., 2019;Provost et al., 2020b) to facilitate enforcement at sea. The identification of fish aggregations (Vanderlaan et al., 2014), spawning locations (Harrison et al., 2020), and critical nursery habitats (Harris et al., 2019;Ventura et al., 2016) to monitor illegal fishing activities (Provost et al., 2020a) also confirms the ideal role of UAV remote sensing in fisheries regulation. ...
With the booming development of information technology and the growing demand for remote sensing data, unmanned aerial vehicle (UAV) remote sensing technology has emerged. In recent years, UAV remote sensing technology has developed rapidly and has been widely used in the fields of military defense, agricultural monitoring, surveying and mapping management, and disaster and emergency response and management. Currently, increasingly serious marine biological and environmental problems are raising the need for effective and timely monitoring. Compared with traditional marine monitoring technologies, UAV remote sensing is becoming an important means for marine monitoring thanks to its flexibility, efficiency and low cost, while still producing systematic data with high spatial and temporal resolutions. This study visualizes the knowledge domain of the application and research advances of UAV remote sensing in marine monitoring by analyzing 1130 articles (from 1993 to early 2022) using a bibliometric approach and provides a review of the application of UAVs in marine management mapping, marine disaster and environmental monitoring, and marine wildlife monitoring. It aims to promote the extensive application of UAV remote sensing in the field of marine research.
... Illegal fishing is a global problem that threatens the viability of fishing industries and causes profit loss to farmers. On-the-ground surveillance is the typical way to monitor or minimize this practice [134], but with a very high operational cost. Submersible drones and UAVs are now capable of detecting illegal fishing activities [135] and are lower in terms of cost [136,137]. ...
... The drone provides visual information using its installed camera. Additionally, crabs are highly valued commercial commodities, and also used drones with infrared cameras to detect crab traps and floats [134,135] to prevent illegal activities. ...
This paper aims to provide an overview of the capabilities of unmanned systems to monitor and manage aquaculture farms that support precision aquaculture using the Internet of Things. The locations of aquaculture farms are diverse, which is a big challenge on accessibility. For offshore fish cages, there is a difficulty and risk in the continuous monitoring considering the presence of waves, water currents, and other underwater environmental factors. Aquaculture farm management and surveillance operations require collecting data on water quality, water pollutants, water temperature, fish behavior, and current/wave velocity, which requires tremendous labor cost, and effort. Unmanned vehicle technologies provide greater efficiency and accuracy to execute these functions. They are even capable of cage detection and illegal fishing surveillance when equipped with sensors and other technologies. Additionally, to provide a more large-scale scope, this document explores the capacity of unmanned vehicles as a communication gateway to facilitate offshore cages equipped with robust, low-cost sensors capable of underwater and in-air wireless connectivity. The capabilities of existing commercial systems, the Internet of Things, and artificial intelligence combined with drones are also presented to provide a precise aquaculture framework.
... Outbreaks are influenced by microbial shifts as a consequence of natural disasters, heavy anthropogenic activity (e.g. illegal fishing, deep-sea diving, tourism, trade), and/or fluctuations in temperature (Provost et al., 2020). The ability to rapidly detect the presence and abundance of specific pathogens directly, or monitor environmental cues to predict a potential outbreak, provides the best opportunity for implementation of mitigation strategies. ...
... These materials can be affixed with detectable sensors that allow the structures to be routinely monitored. Such data streams can now be integrated and perhaps deep learning algorithms (Fallati et al., 2019;Liawatimena et al., 2020;Meng et al., 2018;Provost et al., 2020;Yang et al., 2020) would allow such systems to become predictive, affording valuable time to circumvent an impending outbreak. ...
Aquaculture is the fastest growing food-production sector and is vital to food security, habitat restoration and endangered species conservation. One of the continued challenges to the industry is our ability to manage aquatic disease agents that can rapidly decimate operations and are a constant threat to sustainability. Such threats also evolve as microbes acquire resistance and/or new pathogens emerge. The advent of nanotechnology has transformed our approach to fisheries disease management with advances in water disinfection, food conversion, fish health and management systems. In this review, several nano-enabled technology successes will be discussed as they relate to the challenges associated with disease management in the aquaculture sector, with a particular focus on fishes. Future perspectives on how nanotechnology can offer functional approaches for improving disinfection and innovating at the practical space of early warning systems will be discussed. Finally, the importance of "safety by design" approaches to the development of novel commercial nano-enabled products will be emphasized.
... For example, in 2014, this technology was used to monitor the Blue Amazon, comprising 3.6 million km² of expressive marine biodiversity along the entire Brazilian coast (CONSTÂNCIO, 2014). In another assessment, PROVOST et al. (2020) indicated UAV as a tangible, easy-to-implement tool that positively contributes to fisheries management improvement and sustainability when monitoring the use of illegal fishing traps to capture crabs in small estuaries. The WAITT INSTITUTE (2014) and TYLER et al. (2018) also carried out research corroborating the importance of this technology in several fishing assessments, reiterating its low costs in this regard. ...
This article presents an experimental study to verify the feasibility of using the emerging UAV technology in the mapping of fishing grounds exploited by artisanal fishing in Sepetiba Bay, in the south of the state of Rio de Janeiro-Brazil, aiming to better understand the functionality and information generated by the equipment, and whether the data can help improve local fisheries management and also provide information for the implementation of simplified traceability for regional fish. The study area included four locations, Ilha da Madeira, Vila Geny, Coroa Grande and Ponte Preta, all located in Sepetiba Bay, located in the municipality of Itaguaí, in the southern region of the state of Rio de Janeiro. The aerial mapping was carried out in September, October and November 2017, between 10 am and 12 pm (GMT-3), employing a Phantom 3 Professional UAV (DJI, Shenzhen, China), Anac Brasil registration number PP-011092014. The onboard camera a DJI 4K Edition Sony Exmor R Model IMX117: 7.81mm equipped with a CMOS sensor dimension of 6.2 mm, 4000 x 3000 12 megapixel resolution, with an f/2.8 lens and field of view (FOV) of 94, having a focal length of 14mm. Images were collected perpendicularly to the main plan. Flight height was set at 80 m, flight speed was determined based on the overlap of 80%, dimension of area to be mapped, and battery life. Hence, the operator utilized a average flight speed of 25 km/h. ground sample distance (GSD) was 1.20 cm/px. and an overlap of 80% between images was established to avoid possible failures and orthomosaic information gaps. For each fishery mapped, standard software processing was carried out, which consists of: aligning the photos, creating a point cloud, creating a digital elevation model, and finally the orthomosaic itself. Once processed, the orthomosaics were exported from Agis Soft Photo Scan Professional to Google Earth (Google Inc.), where it is possible to make a more comprehensive assessment of fisheries in a much more practical and faster way. A total of four flights were carried out, one for each study area, averaging 10 minutes each. As a result, the technology proved to be viable to apply, since it made it possible to identify and map the areas defined for this research, generating data such as distance and, characteristics of the place, which could be used to track the fish caught and landed, in addition to enabling the monitoring of vessels and fishing, and thus improve the management of local fisheries. RESUMO: Este artigo apresenta um estudo experimental para verificar a viabilidade de uso da tecnologia emergente UAV no mapeamento dos pesqueiros explotados pela pesca artesanal na Baía de Sepetiba, no sul do estado do Rio de Janeiro-Brasil, visando conhecer melhor a funcionalidade e informações geradas pelo equipamento, e se os dados poderão auxiliar na melhoria do gerenciamento da pesca local e também subsidiar informações para a implantação de uma rastreabilidade simplificada para o pescado regional. A área de estudo contemplou quatro localidades sendo Ilha da Madeira, Vila Geny, Coroa Grande e Ponte Preta, todas inseridas na Baía de Sepetiba, localizada no município de Itaguaí, região sul do estado do Rio de Janeiro. O mapeamento aéreo foi realizado nos meses de setembro, outubro e novembro de 2017, entre 10h e 12h (GMT-3), utilizando um VANT Phantom 3 Professional (DJI, Shenzhen, China), registro Anac Brasil PP-011092014. A câmera integrada é uma DJI 4K Edition Sony Exmor R Modelo IMX117: 7,81 mm equipada com sensor CMOS de 6,2 mm, resolução 4000 x 3000 de 12 megapixels, com lente f/2.8 e campo de visão (FOV) de 94, possuindo uma distância focal de 14 mm. As imagens foram coletadas perpendicularmente ao plano principal. A altura de voo foi fixada em 80 m, a velocidade de voo foi determinada com base na sobreposição de 80%, dimensão da área a ser mapeada e duração da bateria. Assim, o operador utilizou uma velocidade média de voo de 25 km/h. a distância da amostra terrestre (GSD) foi de 1,20 cm/px. e foi estabelecida uma sobreposição de 80% entre as imagens para evitar possíveis falhas e lacunas de informações do ortomosaico. Para cada pesqueiro mapeado foi realizado o processamento padrão do software, que consiste em: alinhamento das fotos, criação da nuvem de pontos, criação de modelo de elevação digital, e finalmente o ortomosaico propriamente dito. Uma vez processado, os ortomosaicos foram exportados do Agis Soft Photo Scan Professional para o Google Earth (Google Inc.), onde é possível fazer uma avaliação mais abrangente dos pesqueiros de uma maneira muito mais prática e rápida. Foram realizados um total de quatro voos, um para cada área de estudo, com duração média de 10 minutos cada. Como resultado, a tecnologia mostrou-se viável de aplicação, uma vez que possibilitou identificar e mapear as áreas definidas para nesta pesquisa, gerando dados como distância e características do local, que poderão ser utilizados para rastrear o pescado capturado e desembarcado, além de possibilitar o monitoramento das embarcações e da pesca e assim, aprimorar o gerenciamento da pesca local. Palavras-chave: pescado, pesca artesanal, aeromapeamento, remotely piloted aircraf, rastrabilidade.
... The reliability and utility of small affordable, commercial drones have rapidly improved in recent years [47,48], particularly for monitoring natural habitats such as sandy beaches [46,49,50]. Unlike satellite data, drone-based imagery can have higher resolution, less cloud-cover impact, and can be orthorectified to a higher accuracy using ground control points [51,52]. Furthermore, for localised environmental monitoring such as beach nourishment programs, drones are generally more cost-effective [53,54], safer [54,55], and provide higher resolution imagery than crewed aircraft [56,57]. ...
Beach nourishment is a soft engineering technique that is used to combat coastal erosion. To assess the efficacy of a beach nourishment program on the northwest coast of Lord Howe Island, remotely coordinated drone-based monitoring was undertaken at Lagoon Beach. Specifically, hypotheses were tested that beach nourishment could increase the dune height and the width of the beach where the sand was translocated but would not have any long-term impacts on other parts of the beach. During the beach nourishment program, sand was translocated from the north end to the south end of Lagoon Beach, where it was deposited over 2800 m2. Lagoon Beach was monitored using a time series of 3D orthomosaics (2019–2021) based on orthorectified drone imagery. The data were then analysed using a robust before-after-control-impact (BACI) experimental design. Initially, a fully automated drone mapping program and permanent ground control points were set up. After this, a local drone pilot facilitated automated drone mapping for the subsequent times of sampling and transferred data to mainland researchers. As well as being more cost-effective, this approach allowed data collection to continue during Island closures due to the COVID-19 pandemic. After sand translocation, the south end of Lagoon Beach had a lower dune with more vegetation and a more expansive beach with a gentler slope than the prior arrangement. Overall, drone monitoring demonstrated the efficacy of the beach nourishment program on Lord Howe Island and highlighted the capacity for drones to deliver cost-effective data in locations that were difficult for researchers to access.
... Cardil et al. (2017)). Battery life (35) and operationally difficult categories (36) were discussed frequently in studies, and are interconnected -the discharge rate and weight of a battery are limiting factors affecting both the payload (Frouin-Mouy et al. 2020) and thereby the study area extent (Burr et al. 2019;Hogan et al. 2017;Provost et al. 2020). ...
The ability to adopt novel tools continues to become more important for governments and environmental managers tasked with balancing economic development, social needs and environmental protection. An example of an emerging technology that can enable flexible, cost-effective data collection for conservation and environmental management is Unmanned Aerial Vehicles (UAVs). It is clear that UAVs are beginning to be adopted for a diversity of purposes, identification of barriers to their use is the first step in increasing their uptake amongst the environmental management community. Identifying the barriers to UAV usage will enable research and management communities to confidently utilise these powerful pieces of technology. However, the implementation of this technology for environmental research has received little overall assessment attention. This systematic literature review has identified 9 barrier categories (namely Technological, Analytical and Processing, Regulatory, Cost, Safety, Social, Wildlife impact, work suitability and others) inhibiting the uptake of UAV technologies. Technological barriers were referenced in the literature most often, with the inability of UAVs to perform in poor weather (such as rain or windy conditions) commonly mentioned. Analytical and Processing and Regulatory barriers were also consistently reported. It is likely that some barriers identified will lessen with time (e.g. technological and analytical barriers) as this technology continues to evolve.
... Drones are becoming increasingly used in marine science research, for quantifying fauna presence (Benavides et al., 2019;Schofield et al., 2019) and behaviour (Raoult et al., 2018;Torres et al., 2018) to monitoring fishing activity (Bloom et al., 2019;Provost et al., 2020) and beach usage . Detecting and monitoring sharks from drones to improve the safety of water users is another key area that has recently developed, particularly in Australia Colefax, 2020;Butcher et al., 2021). ...
This report presents the results of the Queensland SharkSmart Drone Trial, which ran from Sept 2020 - Oct 2021. The results include the number of shark sightings, the influence of environmental and operational factors on the ability of drones to detect sharks and a comparison of shark sightings vs catch in shark control nets and drumlines. The report includes recommendations for the future use of drones for shark monitoring at Queensland beaches.
... The first one employs camera-equipped remotely piloted aircraft (Chapman et al., 2014), hereinafter -drones. Given the growing success of drones for supporting coastal management, they may also provide a cost-effective solution for collecting data on recreational fishing effort (Provost et al., 2020a). This approach uses aerial surveys to gather a series of instantaneous counts of the number of active anglers and then extrapolates that information to an estimate of angler effort over an entire fishing season (e.g., Fraidenburg and Bargmann, 1982;Vølstad et al., 2006). ...
As the popularity of recreational fishing gathers global momentum, so does the importance of knowing the number of active anglers and their spatial behaviour. Conventional counting methods, however, can be inaccurate and time-consuming. Here we present two novel methods to monitor recreational fishing applied in Kaunas water reservoir (ca 65 km2), Lithuania, comparing their performance to a conventional visual count. First, we employed a remotely piloted fixed wing drone which conducted 39 missions distributed over one year and compared its accuracy to conventional visual land or boat-based counts. With these data we developed a linear model to predict the annual number of anglers depending on weekday and ice conditions. Second, we used anonymous data from a popular GPS-enabled sonar device Deeper®, used by anglers to explore underwater landscapes and to find fish. The sonar usage probability was calibrated with angler observations from drones using Bayesian methods, demonstrating that at any given time ~2% of anglers are using the sonar device during the open water season and ~15% during the ice fishing season. The calibrated values were then used to estimate the total number of anglers, given the daily records of sonar usage in Kaunas water reservoir. The predicted annual number of anglers from both linear drone-based and Bayesian sonar-based methods gave similar results of 25 and 27 thousand anglers within the area during the period of day surveyed, which corresponded to nearly 110 thousand angling trips in the total reservoir area annually. Our study shows high potential of both drone and fish finder digital devices for assessing recreational fishing activities through space and time.
... As such, regulators are tasked to ensure the safe integration of UAVs into civil airspace (Geoffrey, 2009). Currently, UAV applications span across the following areas: precision agriculture (Tripiccchio 2015), aerial photography, migration and border control (Thompson, 2012), geographical surveying and mapping (McNeil 2016), search and rescue missions (Camara D, 2014), mail and parcel delivery (Bamburry, 2015), filmmaking (Cleveland, 2017), oil and gas exploration (Satterlee, 2016), inspections of public facilities (Jordan, 2017), public safety (Finn, 2011), Weather forecasting (Passner, 2012) as well as in environmental and wildlife monitoring (Casella, 2016;Provost et al., 2020). In spite of its societal benefits, UAVs on the other hand, according to research, pose a threat to safety, privacy and security within civilian air space (Altawy, 2017). ...
In recent times, Unmanned Aerial Vehicles (UAVs) popularly known as drone technology have gradually gained widespread adoption all over the world. UAVs’ relevance within modern society stems from it being able to solve socio-economic issues as well as improve productivity. Sub-Saharan Africa has become a region of global interest with regards to technological development, leapfrogging and foreign investment, despite the lag in socio-economic development in comparison with other regions. Backed by socio-technical theory, the aim of this paper is to investigate UAV adoption and its usage in Sub-Saharan Africa by means of a systematic literature review methodology. Selected papers were reviewed, assessed and results were categorized according to the domain within which UAVs have been and are being deployed in Sub-Saharan Africa. We also determined whether the research reported on existing projects or rather made proposals on the use of UAVs.Our results reveal that UAV adoption in the sub-region is still in its early phase, with a number of implemented cases primarily focusing on healthcare and crop farming. The study makes theoretical and practical contributions to the topic of UAVs/drone technology within the sphere of Sub-Saharan Africa from a socio-technical perspective.
... Technological improvements to remotely piloted aircraft (hereafter called drones, Chapman, 2014) have decreased costs and improved the capacity for collecting high-quality data that can underpin management decisions in coastal environments . Presently, drones have been used effectively to detect abandoned and lost fishing gear (Bloom et al., 2019;Provost, Butcher, Coleman, Bloom, & Kelaher, 2020), improve protected area monitoring and surveillance (Jiménez López & Mulero-Pázmány, 2019;Toonen & Bush, 2018) and stock assessments (Groves, Alcorn, Wiest, Maselko, & Connor, 2016;Raoult & Gaston, 2018), as well as documenting large marine fauna Raoult, Tosetto, & Williamson, 2018) and potentially dangerous sharks in nearshore areas Colefax, Butcher, Pagendam, & Kelaher, 2019). Additionally, the use of dronebased methods can improve results compared with established techniques, through more accurate counts of focal species (Hodgson et al., 2018), increased coverage in challenging habitats (Konar & Iken, 2018) or greater sampling precision (Kelaher, Peddemors, Hoade, Colefax, & Butcher, 2020). ...
Understanding fishing participation assists sustainable fisheries management. Relative to commercial fisheries, however, accurate quantitative data on recreational fishing is often more challenging to collect. The quality and robustness of recreational fishing surveys to assess fisher numbers may be improved with cost‐effective remote sensing platforms, such as aerial drones. Here, the precision and cost‐effectiveness of drone‐based surveys were compared with more traditional vessel‐based surveys of recreational fishing participation at four locations on the east coast of Australia. Although vessel‐based surveys had greater initial costs, this technique observed more fishers, took less time to complete and did not require post‐processing of video footage. In comparison, the drone‐based video surveys provided greater precision and a permanent record of fishing activity. Currently, drone‐based techniques do not provide a substantial improvement to traditional vessel‐based counts of fishers. The complimentary use of drones appears to be an appropriate application of this technology for supporting fisheries management.
Aquaculture and fisheries have been showing constant year-on-year growth worldwide. The increasing human population on the other hand has been demanding more of it. Further intensification of catch and culture of fishes is becoming cumbersome as this requires constant monitoring, precise handling, timely executions and above all assuring sustainability. Thus, it is the very right time for adopting different modern electronical technologies and information technology (IT) devices to better handle fish farming. Because of the sector’s labour-intensive nature, it has been difficult to regulate the ideal characteristics necessary for a good habitat for fish. As a result, in today’s management system, the primary emphasis has been on constant monitoring of water quality measures, which is critical in fish development, well-being and illness prevention. To perform precise quality control, it is also necessary to understand the many chemical and physical properties of water, as well as other environmental elements and their interrelationships. Application of electronics may be indispensable in different aspects of aquaculture and fisheries like water quality monitoring, disease detection, early warning system, automated and demand feeding, maintaining aquaculture value chain, monitoring offshore open sea fish farms, optimizing catch and reducing bycatch, etc. In present time it is imperative to understand and link technological advances with fisheries. This chapter gives a brief view of how the various technologies can be integrated with aquaculture and fisheries for a holistic betterment.
Drones enable the monitoring for sharks in real-time, enhancing the safety of ocean users with minimal impact on marine life. Yet, the effectiveness of drones for detecting sharks (especially potentially dangerous sharks; i.e., white shark, tiger shark, bull shark) has not yet been tested at Queensland beaches. To determine effectiveness, it is necessary to understand how environmental and operational factors affect the ability of drones to detect sharks. To assess this, we utilised data from the Queensland SharkSmart drone trial, which operated at five southeast Queensland beaches for 12 months in 2020–2021. The trial conducted 3369 flights, covering 1348 km and sighting 174 sharks (48 of which were >2 m in length). Of these, eight bull sharks and one white shark were detected, leading to four beach evacuations. The shark sighting rate was 3% when averaged across all beaches, with North Stradbroke Island (NSI) having the highest sighting rate (17.9%) and Coolum North the lowest (0%). Drone pilots were able to differentiate between key shark species, including white, bull and whaler sharks, and estimate total length of the sharks. Statistical analysis indicated that location, the sighting of other fauna, season and flight number (proxy for time of day) influenced the probability of sighting sharks.
The rapid evolution of the Unmanned Aerial Vehicle (UAV) industry has significantly increased interest in UAV design with trans-domain capabilities. It is still a major challenge to achieve miniaturization and enhance the maneuverability and underwater reliability of trans-domain UAVs. In this paper, a novel bullet shape Trans-Domain Amphibious Vehicle (TDAV) is proposed which achieves free trans-domain motion and has the advantages of small size, high maneuverability and high reliability for both rotary-wing UAV and Autonomous Underwater Vehicle (AUV) operation. Compared with traditional amphibious machines, the TDAV design is streamlined and thus inherits the advantages of both the Bamboo Dragonfly and underwater AUVs. The proposed TDAV has a coaxial counter-propeller-tilting platform which satisfies the power and small diameter fuselage requirements, and the blades fold to reduce underwater drag and facilitate transportation. Further, a stable and efficient trans-domain attitude adjustment system is presented which effectively realizes trans-domain attitude switching. Based on the characteristics of the symmetric TDAV body, a rudder blade allocation algorithm is proposed to realize free movement in water. Finally, an improved particle swarm optimization algorithm is used to obtain suitable hierarchical fractional-order PID parameters. Both simulation and outdoor tests were performed and the results demonstrate that the proposed TDAV achieves outstanding performance in terms of lift altitude, trans-domain attitude switching time, and free trans-domain movement in both water and air.
Drones are becoming more accessible and efficient. This article presents a review of recent scientific literature focusing on their use to study wildlife. The 250 publications consulted were grouped into one of 4 categories: wildlife surveys, the behavioural response of wildlife to drones, the study of wildlife behaviour and wildlife protection. The review highlighted the great potential of drones for helping in the survey of animals, especially birds and mammals, and it also revealed the developments underway to allow their use for studying aquatic fauna, amphibians, reptiles and insects. The main impacts of drones on animals are presented and, based on the available information, preliminary recommendations are made to limit their disturbance to wildlife. Drones have multiple advantages and the rapid development of this technology suggests that several of the current limits to their use will soon be overcome. Finally, elements of the Canadian regulations on the use of drones are presented. In conclusion, in the medium-term, drones have the potential to play a significant role in the protection and management of biodiversity.
ContextA series of unprovoked shark attacks on New South Wales (Australia) beaches between 2013 and 2015 triggered an investigation of new and emerging technologies for protecting bathers. Traditionally, bather protection has included several methods for shark capture, detection and/or deterrence but has often relied on environmentally damaging techniques. Heightened environmental awareness, including the important role of sharks in the marine ecosystem, demands new techniques for protection from shark attack. Recent advances in drone-related technologies have enabled the possibility of real-time shark detection and alerting. AimTo determine the reliability of drones to detect shark analogues in the water across a range of environmental conditions experienced on New South Wales beaches. MethodsA standard multirotor drone (DJI Inspire 1) was used to detect shark analogues as a proxy during flights at 0900, 1200 and 1500 hours over a 3-week period. The 27 flights encompassed a range of environmental conditions, including wind speed (2–30.0kmh−1), turbidity (0.4–6.4m), cloud cover (0–100%), glare (0–100%), seas (0.4–1.4m), swells (1.4–2.5m) and sea state (Beaufort Scale 1–5 Bf). Key resultsDetection rates of the shark analogues over the 27 flights were significantly higher for the independent observer conducting post-flight video analysis (50%) than for the drone pilot (38%) (Wald P=0.04). Water depth and turbidity significantly impaired detection of analogues (Wald P=0.04). Specifically, at a set depth of 2m below the water surface, very few analogues were seen by the observer or pilot when water turbidity reduced visibility to less than 1.5m. Similarly, when water visibility was greater than 1.5m, the detection rate was negatively related to water depth. Conclusions The present study demonstrates that drones can fly under most environmental conditions and would be a cost-effective bather protection tool for a range of user groups. ImplicationsThe most effective use of drones would occur during light winds and in shallow clear water. Although poor water visibility may restrict detection, sharks spend large amounts of time near the surface, therefore providing a practical tool for detection in most conditions.
Beaches are economically and socially important to coastal regions. The intensive use of beaches requires active management to mitigate impacts to natural habitats and users. Understanding the patterns of beach use can assist in developing management actions designed to promote sustainable use. We assessed whether remotely piloted aerial systems (commonly known as drones) are an appropriate tool for quantifying beach use, and if beach activities are influenced by environmental conditions. Novel drone-based methods were used to quantify beach use. Drone flights recorded 2 km of beach, capturing video footage of the beach from the dune to water interface and the breaker zone. Flights were undertaken during three school holiday periods at four popular beaches in New South Wales, Australia. These videos were later analysed in the laboratory to categorise beach users. Of the total users sampled, 45.0% were sunbathing, 22.8% swimming, 21.2% walking, 10.6% surfing, and less than 0.5% were fishing. Participation in walking, surfing and fishing was similar throughout the sampling periods. However, sunbathing and swimming significantly increased during the austral spring and summer sampling periods. Usage patterns varied significantly among beaches, and during the different sampling periods, suggesting that adaptive management strategies targeted to specific areas are the most appropriate way to protect beach habitats and users. Furthermore, we demonstrate that drones are an effective assessment tool to improve coastal management decisions.
The use of unmanned aircraft systems (UASs), commonly referred to as drones, has rapidly expanded across many scientific disciplines. Like other fields, fisheries research would benefit significantly from broader use of this emerging technology but has lagged behind other disciplines. Like the implementation of satellite and aircraft‐based remote sensing technology in previous decades brought a greater understanding of large‐scale spatial patterns and processes, UAS technology has the potential to put those tools in the hands of individual researchers that can implement them at finer spatial and temporal scales for a fraction of the cost. Our goal is to provide a “how to” for fisheries researchers interested in using UAS technology. We outline the necessary steps for any UAS project from choosing the appropriate platform and sensors to data acquisition and analysis. We also present the current ways UASs are being used in a fisheries research context, as well a potential future research directions. This article is protected by copyright. All rights reserved.
One role of Marine Protected Areas is to protect biodiversity; however, illegal fishing activity can reduce the effectiveness of protection. Quantifying illegal fishing effort within no-take MPAs is difficult and the impacts of illegal fishing on biodiversity are poorly understood. To provide an assessment of illegal fishing activity, a surveillance camera was deployed at the Seal Rocks no-take area within the Port Stephens-Great Lakes Marine Park from April 2017-March 2018. To assess impacts of illegal fishing activity in the no-take area, Baited Remote Underwater Video Systems (BRUVs) were used to quantify abundance and size of snapper Chrysophrys auratus from 2011–2017. BRUVs were also deployed at two nearby fished locations and two other no-take areas to allow comparison. Over 12 months of camera surveillance, a total of 108 recreational vessels were observed illegally fishing within the no-take area (avg 9.0 ± 0.9 per month). The greatest number of vessels detected in a single month was 14 and the longest a vessel was observed fishing was ~ 6 hours. From 2011–2017, the abundance of C. auratus within the Seal Rocks no-take area significantly declined by 55%, whilst the abundance within the other fished areas and no-take areas did not significantly decline over the same period. Lengths of C. auratus in the Seal Rocks no-take area were significantly smaller in 2017 compared to 2013 which was driven by a decline in the number of legal sized fish over 30 cm. Based on mean number of illegal fishers per vessel recorded in the no-take area, and an allowable bag limit of 10 C. auratus per person, it is possible that more than 2,000 C. auratus are removed annually from this no-take area. There is a strong likelihood that illegal recreational fishing is causing a reduction on a fishery targeted species within a no-take MPA and measures need to be implemented to reduce the ongoing illegal fishing pressure.
High seas fisheries remain one of the least transparent global production practices. Distance from shore, coupled with the highly mobile nature of fish stocks, has put attention on new monitoring, control and surveillance technologies to collect spatially referenced data on the location of fishing vessels, gears and even fish stocks and eradicate illegal, unreported and unregulated fishing activity. Faced with their nascent implementation, research is yet to address how these technologies are reconfiguring the roles and responsibilities of public and private actors involved in fisheries management, including who collects and controls fisheries related information. In this paper, we compare three monitoring, control and surveillance technologies that are gaining traction in fisheries; the use of private fish attraction devices in oceanic tuna fisheries, unmanned public drones for marine surveillance and global satellite monitoring of fishing vessels. In doing so, we question how different configurations of actors are structuring flows of information and with what effect on sustainability performance of high seas fisheries. We also explore how these technologies configure new (and imagined) geographies of high seas fisheries which challenge existing modes of fisheries management.
Perhaps the greatest challenge facing global fisheries is that recovery often requires substantial short-term reductions in fishing effort, catches and profits. These costs can be onerous and are borne in the present; thus, many countries are unwilling to undertake such socially and politically unpopular actions. We argue that many nations can recover their fisheries while avoiding these short-term costs by sharply addressing illegal, unreported and unregulated (IUU) fishing. This can spur fishery recovery, often at little or no cost to local economies or food provision. Indonesia recently implemented aggressive policies to curtail the high levels of IUU fishing it experiences from foreign-flagged vessels. We show that Indonesia's policies have reduced total fishing effort by at least 25%, illustrating with empirical evidence the possibility of achieving fishery reform without short-term losses to the local fishery economy. Compared with using typical management reforms that would require a 15% reduction in catch and 16% reduction in profit, the approach of curtailing IUU has the potential to generate a 14% increase in catch and a 12% increase in profit. Applying this model globally, we find that addressing IUU fishing could facilitate similar rapid, long-lasting fisheries gains in many regions of the world.
Unmanned aerial vehicles (UAVs) are increasingly used in marine wildlife research. As technological developments rapidly advance the versatility and functionality of affordable UAVs, their potential as a marine aerial survey tool is quickly gaining attention. Currently, there is significant interest in whether cost-effective UAVs can outperform manned aircraft in aerial surveys of marine fauna at sea, although few empirical studies have compared relative sampling efficiency, accuracy and precision. Civil aviation restrictions, and subsequent available civilian technologies, make it unlikely that UAVs will currently be more effective than manned aircraft for large area marine surveys. UAVs do, however, have the capacity to fill a niche for intensive smaller spatial scale sampling and for undertaking aerial surveys in isolated locations. Improvements in UAV sensor resolutions and alternative sensor types, such as multispectral cameras, may increase area coverage, reduce perception error, and increase water penetration for sightability. Additionally, the further development of auto-detection software will rapidly improve image processing and further reduce human observer error inherent in manned aerial surveys. As UAV technologies and associated methodology is further developed and becomes more affordable, these aircraft will be increasingly adopted as a marine aerial survey tool in place of traditional methods using manned aircraft. © International Council for the Exploration of the Sea 2017. All rights reserved.
Lightweight drones have emerged recently as a remote sensing survey tool of choice for ecologists, conservation practitioners and environmental scientists. In published work, there are plentiful details on the parameters and settings used for successful data capture, but in contrast there is a dearth of information describing the operational complexity of drone deployment. Information about the practices of flying in the field, whilst currently lacking, would be useful for others embarking on new drone-based investigations. As a group of drone-piloting scientists, we have operated lightweight drones for research in over 25 projects, in over 10 countries, and in polar, desert, coastal and tropical ecosystems, with many hundreds of hours of flying experience between us. The purpose of this paper was to document the lesser-reported methodological pitfalls of drone deployments so that other scientists can understand the spectrum of considerations that need to be accounted for prior to, and during drone survey flights. Herein, we describe the most common challenges encountered, alongside mitigation and remediation actions that increase the chances of safe and successful data capture. Challenges are grouped into the following categories: (i) pre-flight planning, (ii) flight operations, (iii) weather, (iv) redundancy, (v) data quality, (vi) batteries. We also discuss the importance of scientists undertaking ethical assessment of their drone practices, to identify and mitigate potential conflicts associated with drone use in particular areas. By sharing our experience, our intention is that the paper will assist those embarking on new drone deployments, increasing the efficacy of acquiring high-quality data from this new proximal aerial viewpoint.
Intertidal monitoring projects are often limited in their practicality because traditional methods such as visual surveys or removal of biota are often limited in the spatial extent for which data can be collected. Here, we used imagery from a small unmanned aerial vehicle (sUAV) to test their potential use in rocky intertidal and intertidal seagrass surveys in the northern Gulf of Alaska. Images captured by the sUAV in the high, mid and low intertidal strata on a rocky beach and within a seagrass bed were compared to data derived concurrently from observer visual surveys and to images taken by observers on the ground. Observer visual data always resulted in the highest taxon richness, but when observer data were aggregated to the lower taxonomic resolution obtained by the sUAV images, overall community composition was mostly similar between the two methods. Ground camera images and sUAV images yielded mostly comparable community composition despite the typically higher taxonomic resolution obtained by the ground camera. We conclude that monitoring goals or research questions that can be answered on a relatively coarse taxonomic level can benefit from an sUAV-based approach because it allows much larger spatial coverage within the time constraints of a low tide interval than is possible by observers on the ground. We demonstrated this large-scale applicability by using sUAV images to develop maps that show the distribution patterns and patchiness of seagrass.
Investigating spatio-temporal variations of species composition in grassland is an essential step in evaluating grassland health conditions, understanding the evolutionary processes of the local ecosystem, and developing grassland management strategies. Space-borne remote sensing images (e.g., MODIS, Landsat, and Quickbird) with spatial resolutions varying from less than 1 m to 500 m have been widely applied for vegetation species classification at spatial scales from community to regional levels. However, the spatial resolutions of these images are not fine enough to investigate grassland species composition, since grass species are generally small in size and highly mixed, and vegetation cover is greatly heterogeneous. Unmanned Aerial Vehicle (UAV) as an emerging remote sensing platform offers a unique ability to acquire imagery at very high spatial resolution (centimetres). Compared to satellites or airplanes, UAVs can be deployed quickly and repeatedly, and are less limited by weather conditions, facilitating advantageous temporal studies. In this study, we utilize an octocopter, on which we mounted a modified digital camera (with near-infrared (NIR), green, and blue bands), to investigate species composition in a tall grassland in Ontario, Canada. Seven flight missions were conducted during the growing season (April to December) in 2015 to detect seasonal variations, and four of them were selected in this study to investigate the spatio-temporal variations of species composition. To quantitatively compare images acquired at different times, we establish a processing flow of UAV-acquired imagery, focusing on imagery quality evaluation and radiometric correction. The corrected imagery is then applied to an object-based species classification. Maps of species distribution are subsequently used for a spatio-temporal change analysis. Results indicate that UAV-acquired imagery is an incomparable data source for studying fine-scale grassland species composition, owing to its high spatial resolution. The overall accuracy is around 85% for images acquired at different times. Species composition is spatially attributed by topographical features and soil moisture conditions. Spatio-temporal variation of species composition implies the growing process and succession of different species, which is critical for understanding the evolutionary features of grassland ecosystems. Strengths and challenges of applying UAV-acquired imagery for vegetation studies are summarized at the end.
We developed a spatially explicit simulation model of poaching behaviour to quantify the relative influence of the intensity, frequency, and spatial distribution of poaching on metapopulation viability. We integrated our model of poaching with a stochastic, habitat-based, spatially explicit population model, applied it to examine the impact of poaching on northern abalone (Haliotis kamtschatkana) metapopulation dynamics in Barkley Sound, British Columbia, Canada, and quantified model sensitivity to input parameters. While demographic parameters remained important in predicting extinction probabilities for northern abalone, our simulations indicate that the odds of extinction are twice as high when populations are subjected to poaching. Viability was influenced by poaching variables that affect the total number of individuals removed. Of these, poaching mortality was the most influential in predicting metapopulation viability, with each 0.1 increase in mortality rate resulting in 22.6% increase in the odds of extinction. By contrast, the location and spatial correlation of events were less important predictors of viability. When data are limited, simulation models of poaching combined with sensitivity analyses can be useful in informing management strategies and future research directions.
1. Many marine protected areas (MPAs) around the world are ‘paper parks’. A key factor contributing to their ineffectiveness is non‐compliance with the rules in place.
2. This paper contributes to the existing academic discussion on ‘paper parks’ by drawing on critical regulation scholarship to develop a theoretical framework to assess and address compliance gaps in MPAs.
3. The theoretical insights are then explored using a case study of the second largest Italian MPA (the ‘Penisola del Sinis‐Isola di Mal di Ventre’), employing a multidisciplinary perspective built on both biological and socio‐legal expertise.
4. The biological study consists of a review including existing unpublished data on biological resources in the MPA coupled with new analyses on the effects of sea urchin harvesting restrictions. The socio‐legal research consists of the analysis of primary qualitative research in the form of semi‐structured interviews conducted with key stakeholders at the local and regional level in 2014, followed by two workshops (one with stakeholders and one with the general public) in 2015 to discuss the research findings collectively.
5. The results show that the Sinis MPA is not achieving its conservation goals, primarily because of actors' non‐compliance with the rules. The interviews with key stakeholders reveal a number of interlinked social, normative and calculative motivations at the basis of non‐compliance. Policy solutions are then offered.
6. This study offers a novel analysis on ‘paper parks’ that may be applicable to other MPAs experiencing similar compliance issues. Copyright © 2016 John Wiley & Sons, Ltd.
Here we discuss how existing fisheries information can be used to detect illegal, unreported and unregulated (IUU) fishing. We do this through a case that was first documented by a nongovernment organization in Costa Rica. The nongovernment organization used national and regional fisheries databases to find evidence suggesting that foreign purse seiners fished illegally in Costa Rican waters. Here, we intend to give this case more exposure, and to provide broad recommendations for tackling IUU fishing. This opinion piece highlights the importance of openly available information and the need for political will to act on IUU fishing.
Every year, millions of pots and traps are lost in crustacean fisheries around the world. Derelict fishing gear has been found to produce several harmful environmental and ecological effects, however socioeconomic consequences have been investigated less frequently. We analyze the economic effects of a substantial derelict pot removal program in the largest estuary of the United States, the Chesapeake Bay. By combining spatially resolved data on derelict pot removals with commercial blue crab (Callinectes sapidus) harvests and effort, we show that removing 34,408 derelict pots led to significant gains in gear efficiency and an additional 13,504 MT in harvest valued at US 831 million in landings could be recovered annually by removing less than 10% of the derelict pots and traps from major crustacean fisheries. An unfortunate common pool externality, the degradation of marine environments is detrimental not only to marine organisms and biota, but also to those individuals and communities whose livelihoods and culture depend on profitable and sustainable marine resource use.
Measuring the ‘level of compliance’ has emerged as a key performance indicator for MPA success internationally. Accurate interpretation of quantitative and qualitative compliance data is critical for determining which compliance activities contribute to specific management outcomes. To demonstrate the value of enforcement data in effective MPA management, more than 5000 enforcement actions from 2007 to 2013 from five New South Wales (NSW) Marine Parks were analysed. Specifically, it was tested whether through time: (i) the number of enforcement actions standardised by surveillance effort declined-indicating that ‘general deterrence’ was being achieved; (ii) the number of repeat offenders decreased-indicating that ‘specific deterrence’ was being achieved; (iii) the number of ‘local community’ enforcement actions standardised by surveillance effort declined-indicating growing support for marine parks was being achieved at the community level; and (iv) the percentage of young offenders (<25 yr) had declined-indicating that education programs targeting young adults were successful. Results indicated that general deterrence was not being achieved, with offence rates being relatively stable between years. In contrast, compliance measures were achieving individual deterrence, with the percentage of repeat offenders being very low (0.13–0.83%). Although compliance strategies may be making some progress in improving local compliance in some marine parks, the overall offence rate of local communities was concerning. The data suggested that there were major differences in compliance rates among age groups of offenders over time, although the percentage of young offenders declined over time in three marine parks. Over the six-year data collection period, there was no discernable improvement in compliance rates in most NSW Marine Parks. Overall, the significant value of collecting and analysing information on enforcement activities for MPAs was demonstrated, an often neglected aspect of their management world-wide.
Marine sanctuaries are areas where the extraction of biota is not permitted. Although most marine sanctuaries have a positive influence on biotic communities, not all sanctuaries are meeting their conservation objectives. Amidst possible explanations (e.g., size, age and isolation), insufficient enforcement is often speculated to be a key driver of marine sanctuary underperformance. Despite this, there are few studies directly linking quantitative enforcement data to changes in biotic communities within marine sanctuaries. Here, we used an asymmetrical-BACI experimental design from 2006–2012 to test whether new enforcement initiatives enhanced abundances of target fishes and threatened species in an existing large sub-tropical marine sanctuary relative to areas open to fishing. Implementation of the new enforcement initiatives in 2010 was associated with a 201% increase in annual fine rate and a significant increase in target fish and elasmobranch abundance, as well as sightings of a critically-endangered shark, in the marine sanctuary relative to areas open to fishing. Overall, these results demonstrate that strengthening enforcement can have a rapid positive influence on target fish and perhaps threatened species in a subtropical marine sanctuary. From this, we contend that increased enforcement guided by risk-based compliance planning and operations may be a useful first step for improving underperforming marine sanctuaries.
Illegal and unreported catches represented 20–32% by weight of wild-caught seafood imported to the USA in 2011, as determined from robust estimates, including uncertainty, of illegal and unreported fishing activities in the source countries. These illegal imports are valued at between 2.1 billion, out of a total of $16.5 billion for the 2.3 million tonnes of edible seafood imports, including farmed products. This trade represents between 4% and 16% of the value of the global illegal fish catch and reveals the unintentional role of the USA, one of the largest seafood markets in the world, in funding the profits of illegal fishing. Supply chain case studies are presented for tuna, wild shrimp and Chinese re-processed Russian pollock, salmon and crab imported to the USA. To address this critical issue of unintended financing of illegal fishing, possible remedies from industry practices and government policies may include improved chain of custody and traceability controls and an amendment to the USA Lacey Act.
Light scattering and color change are two major sources of distortion for underwater photography. Light scattering is caused by light incident on objects reflected and deflected multiple times by particles present in the water before reaching the camera. This in turn lowers the visibility and contrast of the image captured. Color change corresponds to the varying degrees of attenuation encountered by light traveling in the water with different wavelengths, rendering ambient underwater environments dominated by a bluish tone. No existing underwater processing techniques can handle light scattering and color change distortions suffered by underwater images, and the possible presence of artificial lighting simultaneously. This paper proposes a novel systematic approach to enhance underwater images by a dehazing algorithm, to compensate the attenuation discrepancy along the propagation path, and to take the influence of the possible presence of an artifical light source into consideration. Once the depth map, i.e., distances between the objects and the camera, is estimated, the foreground and background within a scene are segmented. The light intensities of foreground and background are compared to determine whether an artificial light source is employed during the image capturing process. After compensating the effect of artifical light, the haze phenomenon and discrepancy in wavelength attenuation along the underwater propagation path to camera are corrected. Next, the water depth in the image scene is estimated according to the residual energy ratios of different color channels existing in the background light. Based on the amount of attenuation corresponding to each light wavelength, color change compensation is conducted to restore color balance. The performance of the proposed algorithm for wavelength compensation and image dehazing (WCID) is evaluated both objectively and subjectively by utilizing ground-truth color patches and video downloaded from the Youtube website. Both results demonstrate that images with significantly enhanced visibility and superior color fidelity are obtained by the WCID proposed.
Sun glint, the specular reflection of light from water surfaces, is a serious confounding factor for remote sensing of water column properties and benthos. This paper reviews current techniques to estimate and remove the glint radiance component from imagery. Methods for processing of ocean color images use statistical sea surface models to predict the glint from the sun and sensor positions and wind data. Methods for higher resolution imaging, used in coastal and shallow water mapping, estimate the glint radiance from the near-infrared signal. The effects of some current methods are demonstrated and possibilities for future techniques are briefly addressed.
Illegal and unreported fishing contributes to overexploitation of fish stocks and is a hindrance to the recovery of fish populations and ecosystems. This study is the first to undertake a world-wide analysis of illegal and unreported fishing. Reviewing the situation in 54 countries and on the high seas, we estimate that lower and upper estimates of the total value of current illegal and unreported fishing losses worldwide are between 23.5 bn annually, representing between 11 and 26 million tonnes. Our data are of sufficient resolution to detect regional differences in the level and trend of illegal fishing over the last 20 years, and we can report a significant correlation between governance and the level of illegal fishing. Developing countries are most at risk from illegal fishing, with total estimated catches in West Africa being 40% higher than reported catches. Such levels of exploitation severely hamper the sustainable management of marine ecosystems. Although there have been some successes in reducing the level of illegal fishing in some areas, these developments are relatively recent and follow growing international focus on the problem. This paper provides the baseline against which successful action to curb illegal fishing can be judged.
Permutational multivariate analysis of variance (PERMANOVA) is a geometric partitioning of variation across a multivariate data cloud, defined explicitly in the space of a chosen dissimilarity measure, in response to one or more factors in an analysis of variance design. Statistical inferences are made in a distribution‐free setting using permutational algorithms. The PERMANOVA framework is readily extended to accommodate random effects, hierarchical models, mixed models, quantitative covariates, repeated measures, unbalanced and/or asymmetrical designs, and, most recently, heterogeneous dispersions among groups. Plots to accompany PERMANOVA models include ordinations of either fitted or residualized distance matrices, including multivariate analogues to main effects and interaction plots, to visualize results.
The issues surrounding illegal, unregulated and unreported fishing, and that of abandoned, lost and discarded fishing gears, leading to ghost fishing, are intensifying. Estuarine crab trapping is likely subject to high levels of illegal and potential ghost fishing, because it also has good economic incentives regarding potential catch, low gear acquisition costs and accessible fishing grounds. To improve the efficiency and effectiveness of fisheries monitoring, control and surveillance operations, the efficacy of small consumer‐grade drones for sighting traps in an estuary in NSW, Australia, was tested. Twelve sets of two flights were undertaken at 20 and 30 m altitude over a 600‐m stretch of estuary for 5 days to quantify the detectability of submerged mesh traps of three different mesh colours. The drone was able to detect the majority of traps efficiently, with depth in relation to water clarity being the main factor affecting detection. In shallow water, detection rates were high for all mesh colours, but in the slightly deeper placements, orange traps were more readily detected. This study demonstrates that drones could be an efficient and reliable tool for rapidly assessing areas for illegal and derelict traps and can be supplemented into land or vessel‐based fisheries operations.
Effective compliance is a key element to the successful management of marine protected areas (MPAs), and requires a suite of tools to generate awareness of MPA rules, and monitor and regulate their use. Using vessel monitoring systems and creating geo-fences around MPA boundaries is an innovative approach to improve such awareness to vessel masters and commercial fishing licence holders with these systems on-board. In 2014, Parks Australia in partnership with the Australian Fisheries Management Authority (AFMA) introduced a purpose-built alert service for commercial fishing licence holders operating in Australian Commonwealth fisheries managed by AFMA that overlap with MPAs (Australian marine parks). The alert service is customised for each individual fishing vessel to notify masters and licence holders when they enter Australian marine parks where their particular fishing method is prohibited. Since the introduction of the alert service in 25 marine parks, fishers have received 3307 alerts, across eight fisheries. It is estimated that 23 of these alerts averted compliance incidents, in turn protecting marine park values and saving AUD$4.7 million in litigation costs. Of significance, there has been no recorded incidence of noncompliance by Australian commercial fishing licence holders and their vessel master's with access to the alert service since its introduction. The information presented here is the first empirical analysis of the effectiveness of geo-fencing to minimise noncompliance in MPAs. The alert service has the potential to become a front-line tool for supporting compliance by commercial fishing licence holders and their master's in Australian marine parks and other large-scale MPAs and MPA networks, globally.
An increase in shark bites, declining shark populations, and changing social attitudes, has driven an urgent need for non-destructive shark monitoring. While drones may be a useful tool for marine aerial surveillance, their reliability in detecting fauna along coastal beaches has not been established. We developed a drone-based shark surveillance procedure and tested the reliability of field-based fauna detections and classifications against rigorous post-analysis. Perception error rates were examined across faunal groups and environmental parameters. Over 316 shark surveillance flights were conducted over 12 weeks, out of a possible 360, with adverse weather preventing most flights. There were 386 separate sightings made in post-analysis, including 17 sightings of shark, 125 of dolphin, 192 of ray, 19 of turtle, 15 of baitfish school, and a further 18 sightings of other fauna. When examining error rates of field-based detections, there were large differences found between fauna groups, with sharks, dolphins, and baitfish schools having higher probabilities of detection. Some fauna, such as turtles, were also more difficult to classify following a detection than other groups. The number of individuals in a sighting, was found to have significant but relatively subtle effects, whilst no environmental covariates were found to influence the perception error rate of field-based sightings. We conclude that drones are an effective monitoring tool for large marine fauna off coastal beaches, particularly if the seabed can be distinguished and post-analysis is performed on the drone-collected imagery. Where live field-based detections are relied upon, such as for drone-based shark surveillance, the perception error rate might be reduced by machine-learning software assistance, such as neural network algorithms, or by utilising a dedicated ‘observer’ watching a high-resolution glare-free screen.
The turbulent waters off ocean beaches provide habitat for large marine fauna, including dolphins, sharks, rays, turtles and game fish. Although, historically, these assemblages have proven difficult to quantify, we used a new drone-based approach to assess spatial and temporal variation in assemblages of large marine fauna off four exposed beaches in New South Wales, Australia. In total, 4388 individual large marine animals were identified from 216 drone flights. The most common taxa, bottlenose dolphins (Tursiops spp.) and Australian cownose rays (Rhinoptera neglecta), occurred in 25.5 and 19.9% of flights respectively. White (Carcharodon carcharias), bull (Carcharhinus leucas) and other whaler (Carcharhinus spp.) sharks were observed in <1% of flights. There was significant variation in the structure of assemblages of large fauna among beaches, with those adjacent to riverine estuaries having greater richness and abundance of wildlife. Overall, drone surveys were successful in documenting the spatio-temporal dynamics of an impressive suite of large marine fauna. We contend that emerging drone technology can make a valuable contribution to the ecological information required to ensure the long-term sustainability of sandy-beach ecosystems and associated marine wildlife.
The impact of ghost fishing in large coastal ecosystems has generated considerable interest. In smaller, understudied systems with fewer stakeholders, derelict fishing gear (DFGs) may have impacts similar to these larger systems at the same relative scale. Four years of side scan sonar surveys in the Mullica River-Great Bay Estuary (New Jersey, USA) supported the recovery of 1776 DFGs off-season by commercial partners. Locations with high densities of recovered DFGs (>200 DFGs/km²) occupied intersections of recreational vessel traffic and commercial crabbing activity. Condition and depth-in-sediment of recovered DFGs was used to evaluate true bycatch (terrapins, whelks, blue crabs) versus species utilizing degraded gear as habitat (juvenile tautog, oyster toadfish). Critically, gear recovered in-season with low cost sonars (an additional 225 DFGs) prevented the accumulation of new DFGs which likely generate the highest percentages of bycatch. Removal of DFGs in this system led to significant ecological (reduced bycatch), economic (>$61,000 in direct pay, reused gear), and anticipated future benefits (increased harvest).
Owing to concerns about derelict portunid traps perpetually fishing (‘ghost fishing’) in southeastern Australia, the utility of escape gaps for minimising temporal catching efficiencies, and damage and mortality, among key species was investigated. Replicate baited traps with (i) no escape gaps (‘conventional’), (ii) three escape gaps (‘escape-gap’ traps), or (iii) three holes where escape gaps would have been if they were biodegradable (‘open-hole’ traps) were deployed and retrieved after short (one and two weeks), medium (four and six weeks) and long soaks (eight and 10 weeks). No trap had bait remaining after any soak. Total catches comprised 17 species, but 70% was blue swimmer crabs, Portunus armatus—most (78%) of which were smaller than a proposed new legal size (≥65 mm carapace length). Many (62%) P. armatus were injured (typically missing one or two appendages), but had few mortalities (total of 5%). Compared to conventional traps, the escape-gap and open-hole traps retained significantly fewer undersized P. armatus across all soaks (by 93 and 96%) and there were less total injuries (by 86 and 97%) and mortalities trap–1 (by 80 and 85%). Irrespective of the trap, catches of total and undersized P. armatus and injuries trap–1 were greater after short (all by up to 3×) than medium or long soaks. Several traps had broken mesh bars, which was negatively associated with P. armatus catches and injuries. Only three other species had mortalities (n = 7). The data support using escape gaps for minimising ghost fishing among derelict portunid traps.
The catch rates and the catch composition of lost nets were investigated during two seasons (fall and winter) in the southern Caspian Sea. A total of 167 surveys were conducted using anchor to retrieve ghost nets, which led to recover a total of 515 monofilaments gillnet. The most abundant caught species in during both seasons was belonged to Alosa caspia (52.1-43.9%). At both seasons, individuals of Huso huso, and Acipenser stellatus were substantially caught below the length at first maturity. The highest mean of catch rates was discovered at 0-10 m depth (2.79 kg), while the depth of 10-20 m provided the lowest amount of catch (2.0 kg). The Spearman correlation test showed that an increase in depth is reflected in lower values of the retrieved ghost nets. Overall, this study revealed that ghost gillnets is widely distributed in the southern Caspian Sea, mainly at the shallow waters.
Excavations at Stavros, Chalandritsa, 20 km south of Patras, Greece, have brought to light an extensive Late Bronze Age settlement, inhabited at least during the 13th and 12th centuries B.C. The settlement covers an area of approx. 12 acres on top of a rocky hilltop, which offers an unobstructed supervision of the wider region. As highly accurate mapping and 3D reconstructions are fundamental for analyses and interpretations in archaeology, the specific area was used as a test area for a comparison between classical topographic survey, airphoto and Unmanned Aerial Vehicle (UAV) based photogrammetry. The settlement was mapped with traditional topographic surveying methods using tachymeter and Differential GNSS system. Digital photogrammetric techniques were applied on analogue airphotos to create (DSMs) and orthophotos from the archaeological site. Two independent low altitude aerial campaigns were carried out using two different UAVs. Computer vision techniques along with photogrammetric analysis techniques were used to perform bundle adjustment with ground control points (GCPs) collected with a differential GNSS receiver. 3D models were created from the imagery captured from the UAV campaigns. Ultra-high resolution orthophotos with a pixel size of 5 cm and DSMs with respective spatial resolution were also created. The orthophotos were validated in terms of georeferencing accuracy and the DSMs were validated in terms of height accuracy. The accuracy of the UAV derived products reaches 99.6% compared to classical topographic measurements. Chalandritsa test site results provide strong evidence that 3D models created by UAV imagery can be accurate enough to perform precise measurements.
Environmental toxicity refers to the impact of a hazard or stressor at one or more levels of biological organization. This impact can range from molecular and cellular levels to whole organism, population, ecosystem, or landscape levels. The statistical methods employed to examine these impacts will reflect the level of organization and the measurements taken at this level. The methods associated with this spectrum are described and illustrated in this article.
Thermal Imaging Techniques to Survey and Monitor Animals in the Wild: A Methodology provides a manual for anyone interested in understanding thermal imaging and its usefulness in solving a wide range of problems regarding the observation of wildlife.
In the last decade, the cost of thermal imaging technology has significantly decreased, making the equipment more widely available. This book offers an overview of thermal physics and the thermal imager, along with a methodology to optimize the window of opportunity so that wildlife can be observed and studied in their natural habitat.
Users will find the knowledge and tools to formulate a sound survey design, with detailed sections on the theory and performance characteristics of thermal imaging cameras utilizing cooled quantum detectors as the sensitive element and additional information on the uncooled micro bolometric imagers which have been introduced into the camera market in past decades.
The methodology presented is logical and simple, yet it presents a detailed understanding of the topic and how it applies to the critically interlinked disciplines of biology, physics, micrometeorology, and animal physiology.
http://store.elsevier.com/Thermal-Imaging-Techniques-to-Survey-and-Monitor-Animals-in-the-Wild/Kirk-Havens/isbn-9780128033845/
A polystyrene (PS) thin film usually displays a very low light reflectivity (< 0.1) because of its low refractive index (n) and frequency-unresponsive n values. This study yet observes a significant boost of light reflectivity to above 0.7 over the visible and near infrared range when the microstructure of PS film is incubated by the drying-induced phase inversion mechanism. Specifically, a liquid layer of PS in dimethylformamide (DMF) cast on a flat substrate is subjected to drying in air at ambient humidity (ca. 65% RH), through which the condensation of moisture and the evaporation of DMF prompts a gradual phase inversion because water and DMF are miscible and DMF vaporizes slowly. PS chains undergo steady contractions accompanying the drying of the cast liquid film, leaving behind a matrix consisting of grains with sizes of ca. 50 nm, of which each is the assembly of smaller nanoparticles. Furthermore, the infrared spectroscopy offers an assessment for the packing density of PS chains in these nanoparticles. In addition, the film possesses a topographic contour composed of adjoining spherulites in micron sizes according to AFM characterizations. In contrast, two control samples fabricated by using typical solvents for PS, toluene and chloroform, invariably present a solar reflectivity of 0.1. In addition to strong surface solar reflectivity, the PS film formed through the phase inversion holds a surface temperature 3.7 °C below that on a TiO2 coating under direct sunlight.
A checklist is provided for monitoring, control and surveillance (MCS) actions to be applied in the areal-based management of marine fisheries and attached biodiversity conservation needs. The application of MCS to underpin compliance enforcement in marine protected and specially managed areas is seen as important in addressing such needs. Spatial, temporal, management and practical considerations are identified as important implementing considerations for effective MCS-based compliance enforcement. Most notably, human activity impact mitigation appears to possess the greatest potential to reduce potentially-harmful and cumulative long-term effects across all relevant spatial-temporal ranges considered. Equally, selection of suitable MCS approaches requires careful consideration of spatial and/or temporal constraints, as well as regulatory requirements. Express reference is therefore made to conservation measures adopted by the Commission of the Conservation of Antarctic Marine Living Resources (CCAMLR) as examples of where specific, areal-based, precautionary, ecosystem-directed and operational MCS measures have been applied. It is concluded that customary MCS measures are suitable for both fisheries management and biodiversity conservation in protected, or specially managed, areas. The importance of cost-benefit considerations, management feedback and information review is also discussed in the context of minimising protected-area MCS costs.
Fisheries enforcement is frequently overlooked in the U.S. federal fisheries management process. However, absent high levels of compliance, without fisheries enforcement even the most robust fisheries management plan may fail. Coupling past studies of compliance in fisheries with studies of regulatory enforcement, this paper identifies several measures for increasing the effectiveness of U.S. federal fisheries enforcement. Implementing these measures into the United States Coast Guard's fisheries law enforcement program will make the Agency's enforcement efforts more effective, potentially increasing the level of compliance in federal fisheries.
Over the last decade, hatchery production of mud crabs has become technically and economically more feasible, enabling evaluation of the potential effectiveness of hatchery release in fisheries enhancement. The high growth rates and limited movement of released crabs mean that fisheries' yields in isolated mangrove systems with restricted recruitment can be enhanced within a few months. Thus, a release program may be an effective strategy for short-term enhancement in carefully selected specific areas. To date, results are very promising, with recovery rates up to 50% and increases in fisheries' yield up to 46% over baseline catches. In contrast, mark-recapture studies in more open mangrove system populations show that recruitment success and subsequent stock abundance may be largely determined by habitat availability. For these populations, restoration of lost or degraded mangrove areas has been shown to be effective in promoting stock recovery through natural recruitment, with replanted mangroves supporting fisheries of equivalent economic value to that of natural mangroves, though it may take some years to reach these levels. Thus, a balanced approach to stock management could integrate both hatchery-release and habitat restoration programs, depending on local conditions and over different time scales, with parallel co-management to support effectiveness.
Shallow rocky habitats in SW Apulia (SE Italy, Mediterranean Sea) were surveyed in late spring 2002 to assess distribution patterns of sea urchins (Paracentrotus lividus and Arbacia lixula) and barren habitats (coralline barrens and bare substrates) in rocky reefs impacted by the destructive fishery of the rock-boring date-mussel Lithophaga lithophaga. Sea urchin density, test size-structure and biomass, and the percent cover of barrens were evaluated at four locations (5-6 km apart from each other), two heavily impacted by the date-mussel fishery and two controls. Sea urchin density and barren habitat cover were assessed at two and three sites (100-300 m apart), respectively, within each location. Sea urchin biomass was evaluated only at the scale of locations. Average density of P. lividus did not significantly change between impacted locations and controls, whereas A. lixula showed a greater density at the impacted locations. Distribution patterns of A. lixula, in addition, differed at the spatial scale of a few metres between impacted locations and controls, being generally more aggregated at the controls. The size-frequency distribution (test diameter) of P. lividus showed a mode at 3-4 cm at the impacted locations compared to a mode at 2-3 cm in the controls. The size-frequency of A. lixula was bimodal at the damaged locations (with modes at 1-2 and 4-5 cm, respectively) and unimodal (with the mode at 4-5 cm) at the controls. Average biomass of both sea urchins (P. lividus and A. lixula) was two- to fourfold greater at the impacted locations (∼600 g wet wt m -2) than at the controls (150-250 g wet wt m-2). Barren habitats had a far greater average cover (mainly of macroalgae) at the impacted locations (from 79% to 96%) than at control locations (from 7% to 21%). These results show that the date-mussel fishery may have the potential to affect distribution patterns of sea urchins and to greatly enhance the percent cover of barren grounds in shallow Mediterranean rocky reefs.
Blue swimmer crabs (Portunus pelagicus) are an economically important crab caught in baited traps throughout the Indo-west Pacific and Mediterranean. In Australia they are traditionally caught using rigid wire traps (approximate to pots) but there has been a recent increase in the use of collapsible pots constructed from polyethylene trawl mesh. Two experiments were conducted in Moreton Bay, Queensland, to determine the ghost fishing potential of lost crab pots on both target and bycatch species and to evaluate the differences between traditional and contemporary pot designs. A lost contemporary, collapsible trawl mesh pot will catch between 3 and 223 R pelagicus per year after the bait has been exhausted, while a traditional wire mesh pot would catch 11-74 crabs peryear. As most fishers now use the collapsible trawl mesh pots, ghost fishing mortality could be as high as 111,811-670,866 crabs per year. Bycatch retention was also higher in contemporary designs. Periods of strong winds appeared to increase the ghost fishing potential of lost pots. The use of escape gaps, larger mesh sizes and construction options that allow for the deterioration of entrance funnels to minimise ghost fishing are recommended to reduce environmental impacts.
Australian fisheries and aquaculture statistics 2016. Fisheries Research and Development Corporation project
Australian Bureau of Agricultural and Resource Economics and Sciences.
(2017). Australian fisheries and aquaculture statistics 2016. Fisheries
Research and Development Corporation project 2014/245. https://
doi.org/10.1109/MLSP.2016.7738853
An inventory of new technologies in fisheries Challenges and opportunities in using new technologies to monitor Sustainable fisheries OECD Green Growth and Sustainable Development Forum
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fisheries Challenges and opportunities in using new technologies to
monitor Sustainable fisheries OECD Green Growth and Sustainable
Development Forum. Retrieved from https://www.oecd.org/green
growt h/GGSD_2017_Issue Paper_Newte chnol ogies inFis heries_
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Goddijn-Murphy, L., & Dufaur, J. (2018). Proof of concept for a model
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