Fishing Activities Research Articles

Shedding light on trawl fishing activity in the Mediterranean Sea with remote sensing data

Abstract This study uses Synthetic Aperture Radar (SAR) vessel detections and Automatic Identification System (AIS) to predict trawl fishing intensity and distribution of fishing activity in areas where public AIS data are not available. By processing SAR data, considering spatial and temporal autocorrelation, and building a General Additive Model, a statistical relationship between SAR vessel detections and AIS fishing activity was established. The study provides spatially explicit estimates of trawler fishing activity, compared with official fleet records published by the General Fisheries Commission of the Mediterranean, revealing the distribution and intensity of trawl fishing activity not previously publicly tracked. Fishing grounds in the Strait of Sicily along the coast of Tunisia and North of Egypt showed an intensity of trawl fishing activity similar to the Adriatic Sea. This area is historically known to be subject to the highest trawling pressure in the Mediterranean, and also as one of the most heavily trawled regions in the world. The study shows that the integration of remote sensing data, such as SAR, offers a promising avenue to overcome data gaps and improve fisheries management in the Mediterranean where only a portion of the fishing fleet is publicly tracked.

Application and effectiveness of adaptive AI in elderly healthcare

AbstractBackgroundIn addressing elderly healthcare issues, cognitive impairment can cause significant disruptions in daily life and may potentially develop into dementia. Thus, finding ways to delay the progression of cognitive impairment is a critical issue.MethodsThis study aims to develop an adaptive artificial intelligence (AI) mechanism that creates enjoyable and beneficial content to help delay cognitive impairment in the elderly. Utilising virtual reality (VR) and a fishing game, the design enhances reaction time and attention through interactive fishing activities. The AI personalises content based on individual performance to improve cognitive function.ResultsExperimental results showed that adaptive AI increased participant satisfaction from 86.84 to 91.05 points and future willingness from 75.26 to 85.68 points. The number of fish caught rose from 98 to 120, with the average per participant increasing from 2.64 to 2.85.ConclusionsThis is undoubtedly the trend of the future. VR allows the elderly to have a more impactful and memorable first experience, while AI dynamically adjusts the game's difficulty based on the elderly's performance, addressing the issue of reduced willingness to continue due to inappropriate game difficulty. The VR game developed in this study is designed to be relaxing and incorporates mechanisms to promote the elderly's health. It is not restricted by location or time and, more importantly, meets the health promotion needs of the elderly.

Scallop fishing activity characterization in Southern New England: Offshore wind demands and fisheries-dependent methods

Managers attempt to minimize spatial use conflicts in siting of offshore wind developments, but they must rely on available data to balance biological, commercial, and recreational needs. Marine spatial planning products are only as good as the data they are built upon and fishing data present major challenges due to their confidentiality and the difficulty in isolating true fishing activity. We present a methodology to increase the spatiotemporal resolution of fishing effort and exposure estimates for Southern New England scallop fishing activity using random decision forests to perform supervised classification on AIS data, with fallback to lower resolution datasets for vessels without AIS coverage. Final predictive accuracy of the tuned random forest AIS model was 97.9%, offering improvements of 24.7, 48.6, and 50% over VTR fishing footprints, and AIS and VMS speed cutoff methods, respectively, to predict whether vessel locations correspond to fishing activity. Comparison of the AIS model with VMS and VTR fallback to the VTR fishing footprints data product demonstrated that the increased precision of the AIS point data delineated as fishing dramatically changed how fishing effort, and therefore exposure in the form of fishery landings values, is distributed spatially in Southern New England wind energy areas. This is due to how the probability of fishing is distributed across location data points in the various products, which has implications for marine spatial planning and mitigation decision-making. Therefore, multiple data products should be considered when evaluating management options, as exposure estimates may differ depending on what inputs are used. The higher resolution AIS product may offer enhanced value in understanding exposure and impacts to individual vessels, especially once wind farms are under construction or operational.

Anthropic Pressure on Cetaceans Stranded Along the Ligurian Coast Within the Pelagos Sanctuary: A Case Series

Data collected by C. Re. Di. Ma over a 3-year period (2020–2022) were considered to assess anthropic pressure on cetaceans living in the Ligurian sea. Out of a total of 37 stranded cetaceans, a complete post mortem examination was performed on 23 cases. Of these, 14 were further selected considering at least one of these conditions: (i) confirmed, probable, or suspected interaction with fishing activities through the application of a standardized diagnostic framework (7/14; 50%), (ii) toxicological stress through the evaluation of OCs hazardous levels (14/14; 100%), and (iii) terrestrial pathogen-associated disease (systemic infection and/or associated lesions) (7/14; 50%). For 9 animals out of a total of 14 selected, the cause of death was classified as natural (6/14; 42,8%), anthropic (3/14; 21,4%), or not determined (5/14; 35,7%) based on gross and histological pathology and ancillary testing. These findings extend our knowledge of the anthropic pressure to which cetaceans stranded along the Ligurian coastline are subjected from a multidisciplinary point of view.

Applying acoustic telemetry, vessel tracking and fisher knowledge to investigate and manage fisher-shark conflict at Lord Howe Island, Australia

Fisher-shark conflict is occurring at Lord Howe Island, Australia due to high levels of Galapagos shark (Carcharhinus galapagensis) depredation (where sharks consume hooked fish) and bycatch. Depredation causes costly loss of target catch and fishing gear and increased mortality of target species, and sharks can be injured or killed when bycaught. This study applied acoustic telemetry and vessel tracking from 2018 to 2021 to identify; (1) how the movements of 30 tagged sharks and activity of six fishing vessels overlapped, and (2) where key ‘hotspots’ of overlap occurred. Fisher surveys were also conducted to collect information about mitigating shark interactions. Residency index analysis indicated that three sharks tagged at a fish waste dumping site had markedly higher residency. Core home ranges of sharks overlapped with higher fishing activity at four ‘hotspots’. Statistical modelling indicated positive linear effects of fishing activity and bathymetric complexity on shark detections and tagged sharks were present for 13% of the total time that vessels were fishing close to acoustic receivers. Spatio-temporal overlaps between shark movements and fishing activity could potentially have occurred because sharks learned to associate fishing vessels with food (i.e. hooked fish) and because fishers and sharks utilise highly productive shelf edge areas, however more research is needed to investigate these relationships. Fishers reported that rotating fishing areas and reducing time at each location, fishing deeper than 100 m, and using electric reels and lures instead of bait, reduced bycatch and depredation. The integrated approach used here identified practical methods for reducing fisher-shark conflict, improving socio-economic outcomes for fishers and conservation prospects for this unique shark population.

Computational design and evaluation of a polyvalent vaccine for viral nervous necrosis (VNN) in fish to combat Betanodavirus infection

Viral nervous necrosis (VNN) poses a significant threat to the aquaculture industry, causing substantial losses and economic burdens. The disease, attributed to nervous necrosis viruses within the Betanodavirus genus, is particularly pervasive in the Mediterranean region, affecting various fish species across all production stages with mortality rates reaching 100%. Developing effective preventive measures against VNN is imperative. In this study, we employed rigorous immunoinformatics techniques to design a novel multi-epitope vaccine targeting VNN. Five RNA-directed RNA polymerases, crucial to the lifecycle of Betanodavirus, were selected as vaccine targets. The antigenicity and favorable physicochemical properties of these proteins were confirmed, and epitope mapping identified cytotoxic T lymphocyte, helper T lymphocyte, and linear B lymphocyte epitopes essential for eliciting a robust immune response. The selected epitopes, characterized by high antigenicity, non-allergenicity, and non-toxicity, were further enhanced by adding PADRE sequences and hBD adjuvants to increase immunogenicity. Two vaccine constructs were developed by linking epitopes using appropriate linkers, demonstrating high antigenicity, solubility, and stability. Molecular dynamics simulations revealed stable interactions between the vaccine constructs and Toll-like receptors (TLRs), essential for pathogen recognition and immune response activation in fish. Notably, vaccine construct V2 exhibited superior stability and binding affinity with TLR8, suggesting its potential as a promising candidate for VNN prevention. Overall, our study presents a comprehensive approach to VNN vaccine design utilizing immunoinformatics, offering safe, immunogenic, and effective solutions across multiple Betanodavirus species. Further experimental validation in model animals is recommended to fully assess the vaccine’s efficacy. This research contributes to improved vaccine development against diverse fish pathogens by addressing emerging challenges and individualized immunization requirements in aquaculture.

Mitigation measures for pinniped-fisheries interactions based on knowledge of animal behavior

Abstract A rise in pinniped-fisheries interactions has been observed due to the global decline in fish populations primarily attributed to overfishing, and/or due to the recent population recovery of several pinniped species. Although many studies have quantified these interactions, a limited number delve into their behavioral aspects. We consulted 374 studies on pinniped-fisheries interactions from 1980 to 2020 and analyzed which of them addressed the interaction from a behavioral perspective. Additionally, we examined the role of learning in pinnipeds and their ability to capture prey from fishing gear. The stimulus-reward relationship in operational interactions was addressed in 51 (14%) studies, involving 10 (19%) of the world’s 54 pinniped species or subspecies. Depredation behavior (43%) and attack behavior (35%) were frequently reported during fishing interactions. Understanding associative and non-associative learning mechanisms has the potential to reduce economic losses from fishing activity, advance efficient mitigation measures to minimize conflicts, and establish pragmatic conservation priorities based on a better understanding of the behavioral aspects of these interactions. More research is needed to explore the effectiveness of deterrents in different species, improve methods of reducing habituation, and evaluate long-term behavioral effects, fostering effective strategies for minimizing conflicts and promoting coexistence between humans and pinnipeds.

Lipoxygenase activity in tropical fish: Changes during surimi processing and some biochemical characterization in lizardfish (Saurida tumbil).

The lipoxygenase (LOX) activity of major tropical fish used for surimi production, including threadfin bream (TB), lizardfish (LZ), and goatfish (GF), was measured in the gills, skin, and muscle. The highest LOX activity was observed in the LZ samples (p<0.05), with the gills exhibiting the greatest activity at 376.56U/mg (p<0.05). The highest peroxide value was detected in the TB samples, particularly in the gills (p<0.05). Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were the main polyunsaturated fatty acids in all the tissues and surimi. The total lipid and DHA contents of washed mince reduced considerably after the screw press process. Although LOX activity decreased during surimi production, a residual activity of 21.33U/g was observed in the finished surimi. LOX was partially purified and characterized from LZ gills. The purification was conducted using two successive chromatographic steps, Sephacryl S-200 and diethylaminoethyl (DEAE)-sepharose, resulting in a 3.52% yield and a 22.43-fold increase in purity. The optimum activity was found at 25°C and pH 7.5, with pH stability between 6.0 and 8.5. The relatively high thermal stability at 4°C-10°C suggested that LOX might contribute to fish lipid oxidation during cold storage. The enzyme was thermally inactivated at 60°C. The preferred substrate was EPA. LOX from the LZ gills was inhibited by 1mM ethylenediaminetetraacetic acid and activated by 1mM Fe2+, Na+, and Ca2+. PRACTICAL APPLICATION: Elucidating lipoxygenase activity and lipid oxidation in various tropical fish tissues, as well as understanding the characteristics of LOX, can help take appropriate postharvest actions to afford high-quality surimi.

Assessing the use of remote underwater video (RUV) to identify fish and their feeding behaviour in New Zealand's Greenshell™ mussel (Perna canaliculus) farms

Fish predation poses a significant and escalating challenge for the global mussel aquaculture industry. In New Zealand, Greenshell™ mussel farms experience crop losses of up to 100 % that are anecdotally attributed to fish predation, although the fish species responsible have not been confirmed. In this study, remote underwater video (RUV) was used to observe fish activity within four mussel farms at different stages of production in the Firth of Thames, New Zealand. The RUV enabled the identification of the fish species inhabiting mussel farms, including those responsible for predating cultured mussels. Four fish species were identified as frequent inhabitants of the mussel farms, with Australasian snapper (Chrysophrys auratus) and parore (Girella tricuspidata) the most abundant at three out of four mussel farm sites. Australasian snapper was the most common predator, taking as many as 2880 bites of the dropper lines holding mussels in a single 11 min 47 s video recording. Snapper formed feeding aggregations around dropper lines holding juvenile mussels (> 20 mm SL), indicating their potential to remove mussels from nursery farms in a short amount of time. Observations of the feeding behaviour of parore indicated their potential to contribute to the losses of mussels on recently seeded spat farms with these fish recorded tearing apart seeded lines, possibly targeting the macroalgae that is seeded out with the mussel spat. Besides confirming the identity and the predatory behaviour of fish species that are contributing to crop losses from mussel farms in New Zealand, this study also confirms the effectiveness of RUV methods for this purpose. This knowledge can be used to begin to develop mitigation strategies aimed at reducing crop losses in mussel aquaculture.

Mathematical approaches to fisheries quota management: ensuring sustainable practices in U.S. commercial fishing

Fisheries quota management plays a critical role in ensuring the sustainability of commercial fishing practices, particularly in the United States, where overfishing and resource depletion pose significant challenges to marine ecosystems. This review explores the mathematical approaches utilized to manage fisheries quotas effectively and sustainably. The paper examines key mathematical models, including population dynamics, bioeconomic models, game theory, and Catch-per-Unit-Effort (CPUE) models, highlighting their role in maintaining fish stock levels and regulating fishing activities. Through case studies from U.S. fisheries, such as the New England groundfish and Alaska pollock fisheries, the review assesses the effectiveness of these models in real-world applications. Additionally, it explores how advances in technology, such as satellite tracking, big data, and artificial intelligence, are enhancing the accuracy and adaptability of fisheries management models. The review concludes with insights into future directions for mathematical approaches in fisheries management, emphasizing the need for continuous innovation to support sustainable commercial fishing practices. By integrating advanced mathematical techniques and data-driven models, this paper aims to provide a pathway for policymakers and fisheries managers to achieve long-term sustainability in U.S. commercial fisheries.

Quantification, characterization, and source identification of macro- and mesoplastics in the water column of Rivers Sabaki and Tana.

Five sampling campaigns were conducted in the water columns of River Sabaki and Tana in Kenya, Between October 2021 and January 2023, covering a 1-year cycle, at four sites in River Sabaki (2.5km, 3.05km, 3.51km, and 4.52km) and River Tana (1.5km, 1.8km, 2.0km, and 2.5km) distant from the river mouth. The ebb and flood tides were sampled to calculate net plastic litter fluxes. Two 6350-µm seine nets were deployed in two replicates per sampling point. Factor and cluster analysis were used to investigate plastic litter sources for both rivers. The influences of rainfall on plastic abundance and mass were explored using permutational linear models. A total of 15,318 plastic litter items weighing 1.37kg were recorded in River Sabaki, and 3741 plastic litter items weighing 0.95kg in River Tana. The top ten captured plastic litter types sorted by abundance and mass were mostly plastic fragments. The annual net plastic litter flux to the ocean through River Sabaki amounted to 1,277,120.63 items year-1 by abundance and 22.30kgyear-1 by mass. For River Tana, the same fluxes were 207,550.76 items year-1, and 28.09kgyear-1, respectively. In River Sabaki, significant impacts of rainfall on plastic abundance and mass were found. River Sabaki's pollution sources included upstream reaches, fishing activities, and littering by locals and tourists. River Tana's major pollution sources were illegal dumpsites, littering, fishing, and recreational activities. This research can guide combat plastic pollution in the rivers and ultimately the ocean.

Prediction on Yellowfin Tuna (Thunnus albacares) Fishing Ground in Waters Near the Marshall Islands Based on SMOTETomek‐RF

ABSTRACTThis study monitored 37 longliners fishing in waters near the Marshall Islands from 2020 to 2022 by Liancheng Overseas Fishery (Shenzhen) Co., Ltd.'s operation management system. This study developed nine predictive models on the relationship between catch per unit effort (CPUE) data for yellowfin tuna (Thunnus albacares) and the environmental data. The environmental data integrate 48 variables, including eddy kinetic energy, chlorophyll a concentration, sea surface height, and additional measures of vertical oceanic conditions, alongside spatiotemporal parameters (year, month, day, longitude, and latitude). This study employed four spatial resolutions (0.25° × 0.25°, 0.5° × 0.5°, 1° × 1°, and 2° × 2°) to develop nine predictive models: KNN, RF, GBDT, CART, LightGBM, XGBoost, CatBoost, AdaBoost, and Stacking (RF, KNN, GBDT, and LR). These models, with a daily time resolution, were trained using 75% of the data and tested with the remaining 25%. The optimal spatial resolution and model were determined through a comprehensive comparison of model evaluation metrics across these spatial resolutions. The SMOTETomek algorithm was then applied to resample 75% of the data at the optimal spatial resolution, forming a new training dataset. This dataset was used to refine the model, subsequently tested with the remaining 25% of the data. Results indicated that (1) the optimal spatial resolution is 0.25° × 0.25° and the optimal model is RF; (2) the SMOTETomek algorithm enhances the model's predictive performance; and (3) the developed SMK‐RF model, exhibiting Acc and AUC values of 76.73% and 82.47%, respectively, accurately predicts the central fishing grounds for yellowfin tuna, consisting closely with actual fishing activity.

Small-scale fisherfolk organizations: Do current conditions facilitate their effective contribution to the value chain?

Small-scale fishing organizations in Colombia face significant barriers in accessing fair markets for their fish products. This reality has led to the development of various support and promotion programs, which have not prospered as sustainable strategies. The aim of this work was to analyze the predominant strengths and weaknesses within fisherfolk organizations, assessing their capacity to be part of a more equitable value chain. The Diagnosis of the Small-scale Fisherfolk Organizations tool (DOPA, for its Spanish acronym) was developed, integrating five components and including 22 indicators. This tool assesses organizations considering five components: i) organizational capacity, ii) social capital and welfare, iii) risks, iv) fishing activity information, and v) commercialization. The obstacles identified within the context of small-scale fishing in a value chain are directly linked with their social fabric, the policy and legislation of development programs, and the lack of understanding of fishing activity as an economic sector. These barriers have impacts on the well-being of fisherfolk as well as on the management of fishing resources.

Analisis Dinamik Model Predator-Prey dengan Efek Pemanenan Pada Populasi Ikan Nike (Awaous Melanocephalus) di Provinsi Gorontalo

Gorontalo Province is one of the areas directly adjacent to Tomini Bay, which is known for its rich natural resources, especially in the fisheries sector such as Nike fish (Awaous melanocephalus). Nike fish is the main food commodity for people in the Gorontalo region. However, intensive fishing activities can pose an extinction threat to this species. This study aims to understand the dynamics of the Nike fish population using a predator-prey model that integrates the effects of harvesting on the prey population. The research process includes formulation of assumptions, model building, model validation, and data analysis through mathematical analysis and numerical simulation. The analysis showed that the model has four equilibrium points, each with different stability conditions. Numerical simulations showed that an increase in harvesting rate and natural mortality of prey, as well as a decrease in birth rate, could threaten the viability of the Nike fish population. Thus, appropriate management efforts are needed to maintain ecosystem balance and the sustainability of the Nike fish population. The calculation results show that the Nike fish production threshold in Gorontalo Province is 8.470.858 kg per year. However, the amount of Nike fish production in Gorontalo Province in 2023 only reached 56,75% of the threshold. This indicates that the production of Nike fish in Gorontalo can still be increased as long as the harvest limit is observed to prevent extinction.

Face mask littering in coastal environment of Coromandel beaches, a comparison between street and beach littering - perspective and perceptions.

The usage of face mask has been encouraged globally to combat the COVID-19 pandemic. However, their improper disposal has begun to impact the environment. In the present study, face mask littering was assessed in sixteen stations across the beaches in Coromandel coast of South India for a period of four weeks. Moreover, an online questionnaire was recorded to evaluate the people's perception about face mask usage and littering. In terms of land use pattern, stations with both fishing and tourism activities had higher abundance of face mask littering when compared with exclusive fishing and tourism stations. The study also found that mask littering was higher in streets when compared to the beaches. Of 163 respondents, most of the respondents preferred using disposable single use masks and 39.9% of the respondents preferred to dispose of the face masks along with other wastes. The study highlights the lack of proper solid waste management, negligent littering, and the need for raising awareness, strategic intervention to control this menace.

Primer registro de la langosta roja (&lt;i&gt;Panulirus penicillatus&lt;/i&gt;) en la costa continental de Ecuador

Panulirus penicillatus is a lobster species primarily found in insular regions but also recorded in coastal continental zones of various countries along the American Pacific. This study reports P. penicillatus for the first time in the coastal area of Manabí Province, mainland Ecuador. Previously, its presence was known only in the Galápagos Islands, where it is a commercial species. The record is based on two adult individuals of P. penicillatus, both collected in October 2023 from fishing activities, one through nighttime apnea diving and the other via artisanal fishing using a gillnet.

Isotopic variability of short-tailed Albatrosses bone collagen (&lt;i&gt;Phoebastria albatrus&lt;/i&gt;) in the Bering Sea area during the holocene

The short-tailed Albatross (Phoebastria albatrus) is a rare bird species today, whose numbers declined significantly in the Holocene due to human fishing activities. Bone remains of albatrosses from archaeological sites of Chukotka, Kamchatka and Aleutian Islands, and from coastal sediments of the Commander Islands were used to analyze the content of stable carbon and nitrogen isotopes in bone collagen. Analysis showed that the isotopic niches of Aleutian and Commander albatrosses diverged during the Holocene. Short-tailed albatrosses of the Aleutian Islands are closer to Holocene albatrosses of Vancouver Island (Canada) by isotopic characteristics.

Penguatan Kapasitas Adaptasi Generasi Z Pedesaan Dalam Menghadapi Variabilitas Iklim

Introduction: The climate variability that occurs in Indonesia results in various losses for society, especially in rural areas. Rural communities whose livelihoods depend on agricultural and fishing activities are very threatened by climate variability which hampers the community's economy. Objective: This service aims to analyze participation in strengthening the adaptation of rural Generation Z in facing climate variability Method: The focus of community service in this activity is the Z generation who live in rural areas. To make it easier to provide information to generation Z. A participatory approach is used in this activity. Result: There are 3 main activities in strengthening adaptation capacity for generation Z, namely: 1. Introduction stage, including a basic understanding of several forms of climate variability that occur in rural areas. 2. Advanced stage, namely providing education regarding the impact of climate variability in rural areas, especially agriculture and fisheries, 3. Adjustment stage, namely developing adaptation strategies that must be carried out when exposure to extreme climate variability occurs. Conclusion: The results of this service show an increase in generation Z's knowledge in anticipating climate variability.

Environmental and economic dynamics of the Galician fishing sector and compared perceptions of the agents involved in the value chain

ABSTRACT This case study analyses and compares the perceptions of agents that participate in different productive and commercial processes of the fishing activity (such as small-scale fisheries, distant-water fisheries and processing and commercialisation companies). It focuses on the regional level (Galicia, NW Spain) and considers sustainability, governance and socioeconomic aspects from the perspective of socioecological systems. Results show similarities and differences in agents’ perceptions related with specific aspects and problems relevant to each group, intersectoral relations and sustainability issues. In this sense, agents share a positive perception of the sustainability objectives proposed by international organisations, as well as concerns about the uncertainty linked to globalisation processes. However, they differ in their evaluation of some specific regulatory measures. Regulatory policies could consider this information in order to achieve a greater degree of complicity and compliance by fishers and other agents of the value chain.

Enhancing Sustainability and Conservation of White Shrimp Penaeus schmitti in Northeast Brazil: Insights Into Life History, Reference Points, and Management Strategies for Beach Seining

ABSTRACTArtisanal fishing significantly not only contributes to socioeconomic development of numerous countries but also exerts pressure on natural populations. The white shrimp (Penaeus schmitti) is a key species in Brazilian artisanal fisheries, yet it is currently classified as data‐deficient. Conducting comprehensive studies on its population dynamics is essential to establish reference points that guarantee sustainable fishing. Therefore, we estimated population parameters to assess status of the white shrimp stock captured by beach seining in Northeast Brazil. Monthly samples of white shrimp were collected using a beach trawl. Based on population parameters, the white shrimp population in the study area, the sex ratio was 1 male to 1.29 females, with females larger and heavier than males. Weight–length relationships revealed positive allometric growth for males, females, and grouped sexes, with no significant difference between sexes. Asymptotic length, t_achor, and growth performance index also did not differ between sexes; however, the growth coefficient was higher for females. Beach trawling in northeastern Brazil predominantly targeted adult white shrimp, with carapace length at first capture (Lc50) averaging 2.12 cm for females and 2.19 cm for males. Mortality and exploitation rates were below maximum sustainable levels, so the stock was classified as underexploited. Overall, beach‐seine fishing was less harmful to this stock (F = 1.42) than motorized fishing and can be considered a sustainable fishing activity for the white shrimp population.