Unwanted Catches Research Articles

Distribution models of deep-sea elasmobranchs in the Azores, Mid-Atlantic Ridge, to inform spatial planning

Elasmobranchs inhabiting depths beyond 200 m are extremely susceptible to overexploitation but are extracted by fisheries around the world either as target species or as bycatch. There is little information available to formulate management strategies to reduce elasmobranch-fishery interactions in the deep sea. In European Union waters, prohibiting the catches of deep-sea elasmobranchs has provided the necessary impetus to study by-catch avoidance of these threatened species. We used over 20 years of fisheries-independent and fisheries-dependent data to model the spatial distribution of 15 species of deep-sea elasmobranchs (12 sharks and 3 rays) captured frequently in the Exclusive Economic Zone of the Azores Archipelago (Mid-Atlantic Ridge) to explore spatial management to reduce unwanted catches of these species. We applied Generalised Additive Models to predict the probability of presence of 15 species, as well as the abundance of 6 of those species, within the Azores EEZ and neighbouring seamounts (up to 2000 m depth), using environmental and operational variables as predictors. Our results identified that depth is most influential in determining the distribution of these sharks and rays, in addition to seafloor topography. Distinctive bathymetric features such as seamounts and ridges were highlighted as areas where the probability of presence of the greatest number of species overlapped. Although not related to habitat, gear type influenced the capture probability of certain species, with the artisanal handline, gorazeira, having lower captures than bottom longline. Our results support using depth-based, area-based, and gear-based tactics to design management measures to reduce elasmobranch bycatch, for more sustainable deep-sea fisheries.

Atlantic mackerel (Scomber scombrus) change skin colour in response to crowding stress.

Wild capture can be stressful for fish. Stress has the potential to induce mortality in released unwanted catches or negative flesh quality consequences in retained ones. Such effects compromise sustainable natural resource management and industry profitability. Mitigating stress during capture is therefore desirable. Biological indicators of stress can objectively inform fishers as to the functional welfare status of catches during fishing operations. If they are to be of practical use in mitigating stress during wild capture events, such indicators must be quantifiable, respond rapidly, reflect the level of induced stress and be easily observable. Atlantic mackerel (Scomber scombrus) are extensively targeted by purse seine fisheries in European waters but are particularly vulnerable to stress. Excessive crowding in the net is thought to be the principal stress mechanism. There is therefore a need to develop indicators of crowding stress for this species so that catch welfare can be improved. Here, we demonstrate that S. scombrus exhibit a skin colour change from predominately green to predominately blue when exposed to crowding stress. In sea cage trials, we induced various degrees of stress in groups of wild‐caught S. scombrus by manipulating crowding density and its duration. Skin colour was quantified in air using digital photography. The colour change occurred rapidly (within the typical duration of crowding events in the fishery), and its magnitude was correlated to the severity and duration of crowding. Bluer fish were also associated with higher levels of plasma lactate. No appreciable colour change was observed in uncrowded (control) groups during the treatment period. Nonetheless, unstressed S. scombrus did turn blue <1 h after death. Together, these results indicate that skin colour change has the potential to be a useful real‐time indicator of crowding stress for S. scombrus and could therefore be used to improve welfare during wild capture fishing.

Disparity among recommended and adopted escape-gap designs and their utility for improving selection in an Australian portunid trap fishery

Over the past decade, most efforts at improving the selectivity of commercial, baited traps targeting the giant mud crab, Scylla serrata in south-eastern Australia have focused on testing rectangular escape gaps (46 mm high × 90–120 mm wide) in spatially and temporally restricted manipulative experiments, followed by some promotion among local fishers. Anecdotal data imply wider adoption of escape gaps throughout unassessed regions of the fishery, but there are no data on escape-gap designs, or if performances correspond to predictions from isolated experiments. This deficit was addressed here via a fishery-wide, observer-based assessment. During two fishing seasons, six observers sampled catches from seven estuaries responsible for 80% of the total S. serrata harvest. Most fishers used collapsible netted cylindrical traps (83% of traps and made from 50–55 mm stretched mesh opening); among which ~10% were fitted with one rectangular escape gap, while 37% had one or two circular escape gaps (85–90 mm diameter). Compared to traps with no escape gaps, those with rectangular escape gaps (46 × 120 mm) reduced the numbers of undersized S. serrata by 92% (similar to observations during previous manipulative experiments); but those with circular escape gaps did not reduce any unwanted catches. Rather, traps with circular escape gaps caught more legal-sized S. serrata, which was attributed to possible species-specific behaviours in the traps and less egress through funnel entrances. This result potentially contributed towards fisher opinions of circular escape-gap success (given they want to maximize desirable catches) and facilitated their wider adoption. The data reiterate ongoing fishery assessments are essential to understand the performances of evolving/devolving gear modifications and ensure intended stakeholder and resource management expectations are realized.

An evaluation of information sharing schemes to identify what motivates fishers to share catch information

AbstractAvoiding unwanted catches and reducing discards is an important objective of fisheries management. Fishers can avoid unwanted catches to some extent by improving selectivity of their fishing operations. This can be achieved through technical measures and gear modifications but also by adjusting when and where fishing takes place. Having access to real-time information, as provided through information sharing within a fleet, can help fishers avoid unwanted catches. Yet, there often remains a reluctance to share catch information with others. This paper compiles information from 15 case study examples of existing information sharing schemes in fisheries throughout the world. We compare the structure and operation of each of these schemes and determine what motivated participants to join and share potentially sensitive catch information. While there is no one-size-fits-all approach to designing and implementing information sharing schemes in fisheries, this paper highlights how industry and stakeholder support is often important, and understanding the needs, concerns, and motivations of any group of fishers is fundamental in developing and expanding such approaches.

Let Them Eat Fish!-Exploring the Possibility of Utilising Unwanted Catch in Food Bank Parcels in The Netherlands.

The Common Fisheries Policy of the European Union was reformed in 2013 with the aim of improving the sustainability of the fishing sector. The Landing Obligation, a cornerstone of this reform, requires fishers to land their unwanted catch instead of discarding it at sea. Existing literature pays little attention to what becomes of this unwanted catch once it is landed. To further the discourse on the sustainable valorisation of unwanted catch, this study explores whether unwanted catch that is safe for human consumption could be used for improving food security. The paper focuses on Dutch food banks, which deliver critical food aid to over 160,000 individuals yearly but struggle to provide all dependant recipients with nutritionally balanced food parcels. The research question is addressed in two ways. The food bank recipients’ willingness to consume UWC is evaluated quantitatively through a survey. Next to this, data from interviews with relevant stakeholders are analysed qualitatively. Results indicate that the Food Bank Foundation and its recipients are willing to receive this fish if it is safe to consume and accessible. However, various factors such as existing infrastructure, lack of economic incentive to donate, competition from non-food and black markets, and the fishing industry’s conflict with the landing obligation might pose barriers to this kind of valorisation. The dissonance between fisheries, food, and sustainability policies is discussed and identified as a key limiting factor. To bridge the differences between these policy areas, we propose public-private partnerships and voluntary agreements among involved stakeholders.

A Deep Learning Approach to Assist Sustainability of Demersal Trawling Operations

Bycatch in demersal trawl fisheries challenges their sustainability despite the implementation of the various gear technical regulations. A step towards extended control over the catch process can be established through a real-time catch monitoring tool that will allow fishers to react to unwanted catch compositions. In this study, for the first time in the commercial demersal trawl fishery sector, we introduce an automated catch description that leverages state-of-the-art region based convolutional neural network (Mask R-CNN) architecture and builds upon an in-trawl novel image acquisition system. The system is optimized for applications in Nephrops fishery and enables the classification and count of catch items during fishing operation. The detector robustness was improved with augmentation techniques applied during training on a custom high-resolution dataset obtained during extensive demersal trawling. The resulting algorithms were tested on video footage representing both the normal towing process and haul-back conditions. The algorithm obtained an F-score of 0.79. The resulting automated catch description was compared with the manual catch count showing low absolute error during towing. Current practices in demersal trawl fisheries are carried out without any indications of catch composition nor whether the catch enters the fishing gear. Hence, the proposed solution provides a substantial technical contribution to making this type of fishery more targeted, paving the way to further optimization of fishing activities aiming at increasing target catch while reducing unwanted bycatch.

Exploring new netting material for fishing: the low light level of a luminous netting negatively influences species separation in trawls

AbstractWe tested if a newly developed luminous netting, VISIONET, could change the vertical behaviour of six commercially important species in a Nephrops (Nephrops norvegicus) trawl fishery. We inserted a V-shaped piece of VISIONET ascending on each side of the tapered section just ahead of a divided codend. The length-based effect on the vertical separation of fishes and Nephrops was quantified, and we evaluated if the presence of VISIONET had the potential to increase the fish capture in the upper compartment. Contrary to our expectation, gadoids entered the lower compartment more frequently than in the control trawl. This was similar to that previously found when applying green LED lights in the tapered section, however opposite for haddock (Melanogrammus aeglefinus). The flatfishes did not respond. Large Nephrops significantly increased their preference for the lower compartment. Our results show that low intensity light is sufficient to alter the vertical distribution of both fishes and Nephrops. Responses of fishes to different variables, including light intensities, need to be studied in more detail to understand the underlying mechanisms and to ultimately reduce unwanted catch more efficiently. Luminous netting can be integrated in any given trawl design and does not require batteries or electronics.

Pre-catch and discard mortality in Northeast Atlantic herring and mackerel fisheries: consequences for stock estimates and advice

Abstract Unaccounted mortality caused by discarding or pre-catch losses is a major challenge for fisheries management. In pelagic fisheries, a considerable proportion of catches may be lost due to intentional release of unwanted catch (slipping) or net bursts (fishing net tears due to the weight of the catch). Here we review and estimate ranges of discard and pre-catch mortality for two important pelagic fisheries, the Northeast Atlantic (NEA) mackerel and Norwegian spring spawning (NSS) herring, and explore the effects on stock estimates and catch advice. We show that mortality caused by discarding, slipping, and net bursts is unknown but probably corresponds to a considerable percentage of total registered catches. Including estimated unaccounted mortality into assessment models leads to underestimation of the stock levels by 3.7–19.5% and 2.8–6.8% for NEA mackerel and NSS herring, respectively, corresponding to up to several million tonnes of fish that die annually due to fishing without being landed. If discard and pre-catch mortality were eliminated, allowed catches could increase by 10–20%. We demonstrate that unaccounted mortality in pelagic fisheries may be substantial, affecting stock estimates and catch advice. This may undermine the sustainable management and efficient use of pelagic resources.

The European Union landing obligation: The compliance problems derived from its multilevel approach

Unwanted catches and discards have contributed to undermining the sustainability of fish stocks. The European Union’s most important step to reduce discards was the implementation of a landing obligation for all its commercial fisheries. However, evaluations by EU authorities and scientists alert of general lack of compliance with this landing obligation. This article inquiries on the factors of institutional nature that could have contributed to this outcome. We identify three important institutional factors related to the EU multilevel governance approach that, through diverse mechanisms, contribute to the landing obligation’s generalized non-compliance: (a) the centralized, top-down governance approach, (b) the influence of special interests and (c) the decentralized enforcement.

The use of a spatial model of economic efficiency to predict the most likely outcomes under different fishing strategy scenarios

The current European Union has been progressively implementing since January 2014 a discard ban which includes the obligation to land unwanted catch for certain regulated species and sizes. Although a full enforcement of the landing obligation has a direct impact on discard reduction through more responsible and selective fishing, fishers argue that it will prompt both a decrease in incomes and an increase in working time onboard. Thus, the measure is in a hold in south-western waters due to the difficulties to implement the ban in mixed fisheries This paper analyzes some possible scenarios which fishers could face under the landing obligation. It is shown the construction of a spatial bio-economic model to infer average costs, incomes and gross profits by fishing ground. We illustrate its use using a coastal trawling fleet based in the northwestern Iberian Peninsula as case study. Results show how fishing ground selection will remain the key factor affecting gross profits, well above the selection of closer fishing grounds, the improvement of fuel efficiency, or extending the length of the fishing trip. Increasing the number of crew members to overcome the expected excess of work time onboard would also be a cost-benefit balanced measure. According to our scenario simulations, to maintain business-as-usual (status quo situation) is the most probable fishing strategy without any regulation change. Fishing strategies are tight and maximized to current economic outcomes. Fishers will be reluctant to change their own fishing unless they are forced to for economic and/or regulatory reasons.

Biogenic Calcium Phosphate from Fish Discards and By-Products

Every year, millions of tons of fish waste are generated from fishing activities, and a similar amount is discarded and returned to the sea as unwanted catches. This material can be used as a biological source for many potential new added-value products, such asobtaining hyaluronic acid from fish eyeballs or extracting collagen from fish skin, but there are not many utilities for fish bones yet. This work tackles the transformation of fish discards into calcium phosphates. Discards from scorpionfish (Scorpaena scrofa) and Atlantic horse mackerel (Trachurus trachurus), as well as by-products generated from aquaculture activities (heads and trimmings frames) of salmon (Salmon salar), were used to obtain calcium phosphate. Biphasic carbonated hydroxyapatite (HA) /beta-tricalcium phosphate (TCP) material was obtained. The biphasic HA-TCP material has a promising range of applications in the biomedical field based on its similarity to calcium phosphates found in human bones in terms of crystallite size and carbonate content. The presence of Na, Mg, Sr, and K ions in the HA-TCP material is very beneficial, since they contribute to bone metabolism and cell adhesion.

The Spanish purse-seine fishery targeting small pelagic species in the Bay of Biscay: Landings, discards and interactions with protected species

Ecosystem-based fishery management (EBFM) is based on a holistic approach, recognising all the interactions within an ecosystem rather than considering single species or issues in isolation. Studies of catch profiles of target and bycatch species for different fleets and metiers are necessary for successful management of target species. Such studies are also needed for the assessment of the interactions and evaluation of the impact on the ecosystems. This paper presents a study of the Spanish purse-seine fleet operating in the Bay of Biscay during the years 2016–2019. It considers the species selectivity and the effect of fishing activities on the pelagic community by assessing the interactions with the endangered, threatened and protected (ETP) species and estimating the discard sizes. For the purpose of this study, the metiers were defined by grouping similar catch profiles, using hierarchical agglomerative cluster analysis. This definition of metier goes beyond the Data Collection Framework (DCF) concepts; it includes specific target species, thus increasing the accuracy. Sampling conducted at sea during the four years of the study demonstrated that; 1) the discards were scarce both in terms of overall values and the proportion of the catch (below 1% for almost all metiers and years); 2) The studied purse-seine fishery is one of the most selective among those harvesting the pelagic domain in the Bay of Biscay; 3) The results also showed that the fleet avoided the unwanted catches, mostly by practising slipping;4) The interaction with the ETPs was almost non-existent. Only a single case of a yellow-legged gull entanglement was recorded, and the bird was released alive. Notably, more than 7500 individuals of 16 species of seabirds and marine mammals were recorded in the vicinity of the fishing grounds. Thus, we conclude that this purse-seine fishery has only a slight impact on the main species of the pelagic ecosystem, due to the purse-seine slipping practices.

A review of bycatch reduction in demersal fish trawls

Otter trawling for fish is one of the world’s most productive yet problematic fishing methods due to its bycatch and discards; issues that have been mitigated in some fisheries by developing more selective trawls. This paper systematically reviews efforts published in international peer-reviewed papers over the past 30 years to identify beneficial (and limiting) factors and propose a way forward in this field. In total, 203 papers were assessed, encompassing many of the world’s fishing regions, and involving > 147 species, although 74% of efforts occurred in Europe mainly focussing on haddock (Melanogrammus aeglefinus) (64 papers) and cod (Gadus morhua) (59 papers). Common, simple modifications have involved increasing lateral-mesh openings to match the morphology of unwanted catches via larger diamond-shaped mesh, or simply turning meshes 45° or 90°, either throughout codends or as strategic windows in the posterior trawl. In some fisheries, more complex grids have improved size or species selection. Fewer attempts have been made to modify the anterior trawl, but varying sweep/bridle lengths, horizontal separator panels and longer headropes have realized benefits depending on species-specific behavioural responses. While the utility of many modifications is indisputable, experimental designs (mostly involving covers, but also alternate hauls and paired comparisons) have, in many cases, suffered low replication and/or confounding variables. These deficits may have compromised some results and contributed to repeated efforts in particular fisheries. We conclude that rigorous empirical assessments, initially focusing on the posterior trawl, but eventually encompassing anterior changes, combined with straightforward interpretation of results for stakeholders, are as important as the simplicity and reliability of modifications. Finally, by assessing the utility, applicability, advantages and disadvantages of the modifications developed, we provide a framework which could be followed in future work to reduce bycatch in these fisheries.

Identifying Persistent Hot Spot Areas of Undersized Fish and Crustaceans in Southern European Waters: Implication for Fishery Management Under the Discard Ban Regulation

The recent establishment of the “landing obligation” under the reformed EU Common Fishery Policy has the twofold objective of reducing the excessive practice of discarding unwanted catch at sea and encouraging more selective and sustainable fisheries. Within this context, the awareness of the spatial distribution of potential unwanted catches is important for devising management measures aimed to decrease discards. This study analyzed the distribution of Hot Spot density areas of demersal fish and crustaceans below the Minimum Conservation Reference Size (MCRS) in four different southern European seas: continental Portuguese coast, Catalan Sea, South of Sicily, Liguria and northern Tyrrhenian Seas using both bottom trawl survey data and information on the spatial distribution of commercial fisheries. Critical areas for discarding were identified as zones where the highest densities of individuals below MCRS were consistently recorded throughout a series of years. Results clearly showed a patchy distribution of undersized individuals in each investigated area, highlighting the overlap between high density patches of both discards and fishing effort. The present findings provide a relevant knowledge for supporting the application of spatial-based management actions, such as the designation of Fisheries Restricted Areas (FRAs), in order to minimize the by-catch of undersized specimens and improve the sustainability of demersal fisheries.

Physiological response and survival of Atlantic mackerel exposed to simulated purse seine crowding and release.

Understanding how animals physiologically respond to capture and release from wild capture fishing is fundamental for developing practices that enhance their welfare and survival. As part of purse seine fishing for small pelagic fish in northern European waters, excess and/or unwanted catches are routinely released from the net in a process called slipping. Due to excessive crowding in the net prior to release, post-slipping mortality rates can be unacceptably high. Atlantic mackerel (Scomber scombrus) support large and economically important purse seine fisheries but are known to be particularly vulnerable to such crowding-induced mortality. Developing management advice to promote post-slipping survival for this species is currently challenging, due to a lack of understanding of how crowding influences their physiology. Here we examine the physiological response, recovery and survival of wild caught mackerel exposed to various degrees and durations of simulated crowding stress in a series of sea cage trials. The magnitude of the physiological response and its time to recovery was positively correlated with crowding density and duration and was characterized by cortisol elevation, energy mobilization and anaerobic metabolite accumulation. There were also indications of osmoregulatory disturbance. Skin injury and mortality rates showed a similar positive relationship to crowding density. The physiological disturbance was recoverable for most fish. Instead, the rate at which mortalities developed and the physiological profile of moribund fish indicated that skin injury, likely arising from abrasive contact with netting and other fish during crowding, was the probable cause of mortality. Injured fish also exhibited a loss of allometric condition relative to non-injured survivors. Crowding treatments were potentially confounded by differences in ambient oxygen reduction, water temperature and pre-treatment fish condition between trials, and densities were replicated only once. These results contribute to the development of welfare conscious fishing practices that aim to reduce post-slipping mortality.

Trial and error: Tactical changes in fishing behaviour can help reduce discards and exposure to chokes, but scientific trials can fail to spot this

Trials conducted on board industry vessels to test gears or alternative fishing tactics are often adopted to test selectivity measures in the field. A challenge trial was conducted on board an Irish demersal vessel in 2015 to assess the potential of tactical and behavioural changes to reduce unwanted catches, in light of the introduction of the EU’s Landing Obligation. Initial analysis of the trial indicated that there had been limited success in avoiding choke species through tactical changes. Feedback from the skipper following the trial, however, indicated that every effort had been made to avoid unwanted catches. Consequently, trial results were further scrutinised to determine what behaviours had been adopted throughout the trial, how catch compositions related to reference vessels at this time and what the major drivers of catch patterns may be. Fishing behaviour and catches for the trial vessel were fairly consistent between both trial months. This was possibly as a result of avoidance behaviours being adopted throughout the whole trial. A comparison with reference vessels indicated that the trial vessel did catch lower proportions of haddock, a key choke, in relation to whiting, a non-choke species. Changes in depth fished and time of day fished could reduce the exposure to discarding haddock but not cod, another key choke. This study highlights the importance of understanding how observation and scientific collaboration with industry may influence fishing behaviour, and how scientists should carefully consider such factors when conducting trials on industry vessels and interpreting subsequent results.

The unintended impact of the European discard ban

Abstract The European Union (EU) discard ban, called the landing obligation (LO), was initiated in 2015 to reduce unwanted catches by EU fisheries. To ease the transition to a system where total allowable catches (TACs) refer to catches rather than landings only, the majority of EU TACs was increased to account for the part of the catch that was previously discarded and would now be landed. The analysis shows an average annual upward adjustment of 36% in TACs since 2015, but these percentages were considerably higher in 2019 and 2020 (reaching 43 and 50%, respectively), when the LO was fully applicable to all fisheries, and particularly for TACs of demersal species (reaching 51 and 60%). These results demonstrate the significant impact that the discard ban has had on the quantities of EU fishing opportunities. Since discarding has not declined in EU fisheries at any significant level, the magnitude of these increases may likely have resulted in a substantial widespread increase in fishing mortality being exerted on European stocks, and thus likely lead to an implosion of the EU TAC system, the Common Fisheries Policy central instrument to manage fisheries in the EU.

Fishery spatial plans and effort displacement in the eastern Ionian Sea: A bioeconomic modelling

The management of fisheries requires well-planned approaches that consider the socio-ecological costs and benefits of management options while minimising conflicts among fishing practices. We developed a framework to anticipate the cost-effectiveness of several fisheries management options, including space-time closures, gear selectivity improvements, and fishing effort reduction of eastern Ionian Sea fisheries. We also examined to what extent these fisheries could be influenced by placing new aquaculture sites into specific areas. We used a dynamic space-time model considering the effect of possible fishing effort displacement on alternative marine areas. A fine-scale distribution of 6 species of high commercial importance, for the eastern Ionian fisheries (central Mediterranean), was used together with the fishing effort distribution of trawlers, purse-seines, and small-scale fisheries to track the implications on several bio-economic indicators. The study revealed that the stocks and the fisheries economics benefited from a 10% reduction in fishing effort for all fishery sectors, while the unwanted fish catch was slightly higher. Thus, although there are notable advantages, this management option is not sufficient to support an EU regulatory framework aiming to promote more selective fishing practices and mitigate unwanted catches. However, we showed that the protection of juveniles, by imposing selectivity improvements or space-time closures on trawlers, slightly reduced the unwanted catch. Nevertheless, the benefit for the majority of stocks and fisheries economics, during the five-year simulation period, was limited. In the case of space-time closures, this is attributed to the offset due to the fishing effort displacement towards other areas. While the benefit on fish populations by improving trawl selectivity, it depends on the species. Finally, the establishment of new aquaculture units could lead to a slight re-allocation of fishing effort along the border of the new sites without substantially affecting the profit of small-scale fisheries. Such findings are useful for fisheries management and broader spatial planning in the Ionian Sea. They will provide insight to policymakers and different fishing sectors, thus enabling a more transparent and participatory decision–making process.

Much ado about nothing: An example of how failed incentives thwarted the implementation of the EU landing obligation

With the introduction of the landing obligation in the EU common fisheries policy, there has been several initiatives to reduce unwanted catches of quota-regulated species. In this study, we present a flexible sorting grid as a potential solution for the problem of bycatch of saithe in the pelagic herring trawl fishery in the Skagerrak. The development of the grid was initiated by the industry and finalised through an industry-science collaboration project. The selectivity of the grid was evaluated through the use of an underwater camera system during conventional trawling with an industrial pelagic herring trawler. The results showed that the grid reduced the bycatch by more than 90%, from approximately 5% to 0.5% of the total catch. Given the scale of the pelagic fishery, this reduction could decrease unwanted bycatch of saithe by up to 1000 tonnes per year in the Skagerrak alone. These results were communicated to national industry and management representatives and to responsible EU management bodies and advisory councils. The work conducted within the project also drew interest at the yearly negotiations between EU and Norway. In their agreement for 2018, the EU and Norway agreed to establish a working group on technical measures in the Skagerrak tasked with reviewing selectivity of pelagic trawls as part of the terms of reference. However, in the agreed record of the delegations, the question of pelagic gear selectivity in the Skagerrak was a non-issue, although they concluded that the demersal bycatch can be substantial, that a sorting grid can reduce this bycatch and a sorting grid remains mandatory for Norwegian vessels in the Skagerrak. We argue that this result can be seen as a missed opportunity for the EU to reduce unaccounted bycatch in the Skagerrak and ensure better implementation of the landing obligation.

The MINOUWApp: a web-based tool in support of by-catch and discards management

Current fishing practices often do not allow adequate selection of species or sizes of fish, resulting in unwanted catches, subsequently discarded, with the consequent negative effects on both marine communities and fisheries profitability. The cross-analysis of density patches of potential unwanted catches and distribution of fishing effort can support the identification of spatial-temporal hot-spots in which the fishing pressure should be reduced to limit the amount of discards. The MinouwApp represents a technological and methodological framework to bring different, and structurally complex, sources of georeferenced data together into a simple visual interface aiming to interactively explore temporal ranges and areas of interest. The objective is to improve the understanding of fisheries dynamics, including discards, thus contributing to the implementation of discard management plans in a context of participative, ecosystem-based fisheries management strategies.