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Purse seiners deploy thousands of Drifting Fish Aggregating Devices (DFADs) in all tropical oceans to catch tropical tunas. Although different designs of DFADs exist, fishers all over the world mainly use bamboo rafts with black netting hanging underneath. However, this type of FADs is responsible for incidental mortality of sea turtles and sharks...
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... Since the mid-2000s, scientists and fishers have been collaborating to develop and test prototypes of dFADs constructed specifically to minimize entanglement of sensitive species, while retaining desired traits of traditional dFADs, such as the ability to aggregate tunas, low cost of materials and durability in the water (Franco et al., 2012;Murua et al., 2016;Restrepo et al., 2018). The (Franco et al., 2009;Moreno et al., 2016). Potential alternative materials that are being tested to maintain buoyancy include balsa wood, although its availability varies by region . ...
Drifting fish aggregating devices (dFADs) are human‐made floating objects widely used by tropical tuna purse seine (PS) fisheries to increase catch of target species. However, dFAD use has several negative impacts, including increased potential for overfishing, higher juvenile tuna catch, higher bycatch compared to other PS fishing modes, ghost‐fishing, and generation of marine litter. Based on these impacts, some stakeholders, especially environmental non‐governmental organizations and other competing fishing industries, suggest that dFADs should be completely banned. We list the pros and cons of dFAD fishing; address how to improve current management; and suggest solutions for the sustainability of dFAD fishing in the long term. A dFAD ban would lead to major changes in the availability and sourcing of tuna for human consumption and decrease the licensing revenue received by many developing states. Most importantly, we argue that tools exist today to manage for, reduce or eliminate most of the negative impacts of dFADs (e.g., bans on discards, limits on active dFADs, biodegradable non‐entangling constructions, time‐area deployment closures, recovery programs, and full data transparency, among others). Management decisions based on sound scientific reasoning are needed to address the legitimate concerns surrounding dFAD use and ensure the sustainability of both pelagic and coastal ecosystems and tropical tuna PS fisheries.
... Beberapa faktor yang mempengaruhi hubungan panjang-berat ikan adalah musim, habitat, tingkat kematangan gonad, jenis kelamin, pola makan, kesehatan, perbedaan rentang panjang, jumlah sampling spesimen yang tertangkap (Tesch, 1968;Rekha et al, 2021). Bervariasinya bentuk dan ukuran ikan adalah dikarenakan sesuai dengan fungsi rumpon itu sendiri yaitu sebagai perangkat pengumpul ikan (Fish Aggregating Devices/FADs) struktur buatan manusia yang dipasang untuk mengapung di laut untuk mengumpulkan ikan (Franco et al., 2009). ...
Rumpon merupakan alat bantu yang berfungsi sebagai tempat berkumpulnya ikan sehingga mempermudah nelayan dalam mencari ikan. Penelitian ini bertujuan untuk mengetahui indeks keragaman, dominansi serta bobot dan panjang ikan hasil tangkapan pada rumpon berbasis sumberdaya lokal. Hasil penelitian ini diharapkan dapat memberikan informasi mengenai jenis-jenis ikan yang tertangkap dengan menggunakan pancing ulur. Penelitian dilakukan pada bulan Agustus sampai bulan Desember 2022 di perairan Kuala Daya Kabupaten Aceh Jaya. Data yang dikumpulkan berupa data jumlah ikan (ekor), bobot (gr) dan panjang (cm). Metode pengumpulan data yang dilakukan adalah eksperimental fishing selama 4 trip pada dua lokasi berbeda. Selama penelitian jumlah hasil tangkapan yang diperoleh sebanyak 14 ekor ikan yang terdiri dari 1 filum (chordata), 1 kelas (actinopterygii), 1 ordo, 4 famili dan 7 spesies, adapun jenis ikan yaitu kuwe/rambai (Carangoides malabaricus), selar hijau (Atule mate), selar ekor kuning (Selaroides leptolepis), kerapu macan (Ephinephelus coioides), swanggi (Priachantus hamrur), kakap merah (Lutjanus malabaricus), tenggiri papan (Scomberomorus commerson). Hasil penelitian menunjukkan bahwa nilai indeks keragaman pada rumpon 1 dan rumpon 2 adalah sebesar 1,33 dan 1,21 yaitu termasuk dalam kriteria relatif sedang. Nilai indeks dominansi pada kedua rumpon adalah sebesar 2 dan 2 yaitu termasuk dalam kriteria relatif tinggi, serta bobot ikan hasil tangkapan pada kedua rumpon adalah sebesar 2,72 kilogram dan 1,91 kilogram dan panjang rata – rata ikan hasil tangkapan pada kedua rumpon adalah berkisar antara 14,4 cm – 40,25 cm dan 20,9 – 40,5 cm.
... These first trials with non-entangling biodegradable dFADs were mainly concerned with testing suitability of natural materials such as jute (Corchorus capsularis), sisal (Agave sisalana), and palm leaves (Family Arecaceae) [33]. Subsequently, small pilot projects with a few deployments of experimental biodegradable dFADs were conducted in the Indian and Atlantic oceans, also using bamboo rafts, sisal and jute ropes [35,36]. Similarly, the IATTC conducted a set of biodegradable anchored FAD tests in a controlled lagoon environment in Achotines (Panama). ...
The structure, materials and designs of drifting Fish Aggregating Devices (dFADs) have generally remained rudimentary and relatively unchanged since they first came into use in the 1980 s. However, more recently, dFADs have been increasing in dimensions and the prevailing use of plastic components. Abandoned, lost or discarded dFADs can therefore contribute to the global marine litter problem. Transitioning to biodegradable and non-toxic materials that have a faster rate of decomposition, and are free of toxins and heavy metals, relative to synthetic materials, has been prescribed as an important part of the solution to reducing marine pollution from industrial tuna fisheries that rely on dFADs. This review of the current state of dFADs considers aspects related to the use of biodegradable materials in their construction, including; regulations related to dFAD materials, trials of biodegradable designs and materials and future alternatives. During the last decade, regulatory measures at tuna Regional Fishery Management Organizations (tRFMOs) have gradually moved towards the clear recommendation to use biodegradable materials in dFAD construction together with other measures limiting the number of active dFADs and the use of netting materials. However, to provide operational guidance, more clarity is needed, starting with a standardised definition of biodegradable dFADs among tRFMOs. Research involving dFAD natural and synthetic materials is required, along with improved data collection for monitoring the transition of dFAD materials against specified standards for biodegradable dFADs. In addition, alternative and complementary actions need to be explored to contribute to minimising adverse effects of dFADs on the environment. Acknowledging the current difficulties for the implementation of fully biodegradable dFADs in tuna fisheries, a stepwise process towards the implementation of commercially viable biodegradable dFADs should be considered.
... Several plant fibers such as cotton, sisal, hemp and linen were analyzed for the construction of ropes, and parameters like potential biodegradation, resistance, reproducibility, and availability in the market were assessed [20]. Previously, some small-scale trials were conducted by purse seine companies, ISSF and research institutes to test some of these plant fibers in bioFAD construction under real sea conditions in the Atlantic [24,25], Indian [26,27] and Pacific Oceans (pers. comm. ...
Drifting Fish Aggregating Devices (dFADs) are currently made with synthetic and non-biodegradable materials contributing to the increase of marine litter and other potential ecosystem impacts. Tuna RFMOs have promoted the research and progressive replacement of existing FADs by non-entangling biodegradable FADs (bioFADs). Here, we present the results of the first large-scale biodegradable FAD project in the Indian Ocean to develop and implement the use of non-entangling biodegradable dFADs. The bioFAD tested were fully non-entangling without netting minimizing completely the risk of entanglement. Tested bioFADs significantly contribute to the reduction of the synthetic plastic-based materials, increase the use of biodegradable materials and reduce the total material weight used in FADs, reducing their overall ecosystem impacts. The results of testing 771 bioFADs in real fishing conditions, showed that the fishing performance regarding presence/absence of tuna around dFADs, first day of tuna detection, proportion of FADs occupied by tuna, biomass aggregation underneath the FADs and catch per set between bioFADs and conventional dFADs were similar. This provides support for the efficacy of bioFADs regardless of the degradation experienced by the biodegradable materials tested. Although some bioFADs lasted up to one year, the degradation of the biodegradable material was important and some bioFADs lost their original structure after the study period, suggesting the need to find alternative designs for bioFADs that will suffer less structural stress than those bioFADs made of biodegradable material but with conventional design. The lessons learnt in this large-scale trial will contribute to refining the future designs of biodegradable FADs.
... Since the mid-2000s, scientists and fishers have been collaborating to develop and test prototypes of dFADs constructed specifically to minimize entanglement of sensitive species, while retaining desired traits of traditional dFADs, such as the ability to aggregate tunas, low cost of materials and durability in the water (Franco et al., 2012;Murua et al., 2016;Restrepo et al., 2018). The (Franco et al., 2009;Moreno et al., 2016). Potential alternative materials that are being tested to maintain buoyancy include balsa wood, although its availability varies by region (Moreno et al., 2016). ...
... Les DCP dérivants utilisés par les flottilles des senneurs sont généralement constitués de radeaux rectangulaires en bambou, plastique ou métal d'environ 4 à 6 m² recouverts de vieux filets de pêche ou plus récemment de matériaux non maillants pour rendre le DCP moins visible à la surface et empêcher leur vol (Fig. I.4 ;Franco et al. 2009;Maufroy et al. 2015). Des flotteurs en plastique ou en éthylène-acétate de vinyle sont généralement attachés sous les radeaux pour assurer leur flottabilité. ...
... By contrast, the eastern equatorial Atlantic Ocean is characterised by the prominence of the Equatorial Undercurrent (EUC), a strong permanent eastward flow located just below the westward South Equatorial current (Johns et al., 2014). FADs built and deployed in the Atlantic Ocean have tails going down to 80 m, longer than in the other oceans (Franco et al., 2009), and at a depth where the core of the EUC is found along the equator (Johns et al., 2014). These deep tails likely slow down the drift of the FADs as compared to the shallow subsurface structure of the drifters, explaining our results. ...
... More generally and although the mechanisms of associative behavior of tuna to FADs remain poorly understood (Fréon and Dagorn, 2000), tuna fishermen consider that deeper tails increase the attraction of tunas by slowing down the FADs (Franco et al., 2009). The depth of FAD tails were also shown to affect the tuna species composition (Lennert-Cody et al., 2008) and the arrival of fish (Orúe et al., 2017) at FADs, with tunas arriving earlier with deeper tails. ...
La pollution marine est l’une des principales menaces qui pèsent sur les océans. Une partie importante des déchets et polluants marins provient des activités maritimes, en particulier la pêche, en raison d'équipements jetés, abandonnés, ou perdus. La pêche au thon tropical à la senne contribue à ce problème en construisant et déployant un nombre important de Dispositifs à Concentration de Poissons dérivants (DCP), dont de nombreux sont perdus ou s’échouent en endommageant des habitats fragiles tels que les récifs coralliens. L’objectif général de cette thèse est de proposer trois mesures pour atténuer ces problèmes dans les Océans Indien et Atlantique. Tout d’abord, l’interdiction de déployer des DCP dans les zones risquées permettrait d’éviter un nombre considérable d’échouages. Entre 20% et 40% des échouages pourraient être évités si les déploiements étaient interdits dans l'Océan Indien au sud de 8°N de latitude, dans la zone somalienne en hiver, mais également dans la zone située à l’Ouest des Maldives en été, et au niveau de la zone intertropicale longeant la côte Ouest de l’Afrique pour l'Océan Atlantique. Ensuite, l’identification de régions où les DCP sortent massivement des zones de pêches, ainsi que le passage d’un grand nombre de DCP à proximité de ports, ont mis en évidence que la mise en place d’un programme de récupération des DCP en mer serait efficace pour diminuer considérablement leur perte. Ces deux mesures (interdiction de déploiement et récupération en mer) apparaissent complémentaires puisque les zones qui bénéficieraient moins du premier programme seraient davantage protégées par le second, en particulier au niveau du Nord-Ouest de l'Océan Indien et du Nord du Golfe de Guinée. Enfin, l’évaluation d’un outil de transport Lagrangien pour simuler les trajectoires des DCP a montré que l’efficacité de cet outil à l’échelle du bassin est relativement bonne dans les deux océans, que la capacité à simuler les trajectoires est meilleure dans l’Océan Indien que dans l’Océan atlantique, et que cette capacité dépend de la profondeur et de la résolution spatiale du produit de courant de forçage utilisé. Cet outil pourrait être utilisé en mode opérationnel dans le futur pour anticiper les trajectoires des DCP pouvant conduire à une perte ou à un échouage et donc être utilisé comme un programme de mitigation complémentaire aux deux autres programmes. Les résultats obtenus au cours de ces différents travaux constituent ainsi une base solide pour définir de nouvelles recommandations permettant d’atténuer les risques de perte et d’échouage des DCP et ainsi contribuer à la préservation de nos océans et de nos littoraux.
... It applies the velocity fields of the ocean circulation model to each particle with a fourth-order Runge-Kutta numerical discretization method that is applied over space and time (Paris et al. 2013). Particles were modeled as surface-drifting rectangular rafts of approximately 6 m 2 surface area and a 20-m subsurface net structure, akin to those used commonly in the Indian Ocean (Franco et al. 2009). Particles were neutrally buoyant and passive to prevailing oceanographic currents. ...
... We modeled the dispersal of dFADs with underwater structures that extended down 20 m, typical of those used in the Indian Ocean (Franco et al. 2009). However, dFAD characteristics vary between fleets and by ocean. ...
... For example, IOTC resolution 19/02 (IOTC 2019) requires, as of 1 January 2020, daily information on all active dFADs to better manage important fish stocks. Also encouraged are deployment and management of dFADs to minimize the probability of loss or incursion into protected waters; use of ecologically friendly dFADs to reduce ghost fishing (Franco et al. 2009); and increased use of biodegradable materials. These are emphasized in the updated guidelines for implementing MARPOL Annex V that notes that fishing gears, once discharged, are harmful substances and thus fishers are required to minimize the probability of loss, report losses, and to maximize recovery. ...
Mapping and predicting the potential risk of fishing activities to large marine protected areas (MPAs), where management capacity is low but fish biomass may be globally important, is vital to prioritizing enforcement and maximizing conservation benefits. Drifting fish aggregating devices (dFADs) are a highly effective fishing method employed in purse seine fisheries that attract and accumulate biomass fish, making fish easier to catch. However, dFADs are associated with several negative impacts, including high bycatch rates and lost or abandoned dFADs becoming beached on sensitive coastal areas (e.g., coral reefs). Using Lagrangian particle modeling, we determined the potential transit of dFADs in a large MPA around the Chagos Archipelago in the central Indian Ocean. We then quantified the risk of dFADs beaching on the archipelago's reefs and atolls and determined the potential for dFADs to pass through the MPA, accumulate biomass while within, and export it into areas where it can be legally fished (i.e., transit). Over one‐third (37.51%) of dFADs posed a risk of either beaching or transiting the MPA for >14 days, 17.70% posed a risk of beaching or transiting the MPA for >30 days, and 13.11% posed a risk of beaching or transiting the MPA for >40 days. Modeled dFADs deployed on the east and west of the perimeter were more likely to beach and have long transiting times (i.e., posed the highest risk). The Great Chagos Bank, the largest atoll in the archipelago, was the most likely site to be affected by dFADs beaching. Overall, understanding the interactions between static MPAs and drifting fishing gears is vital to developing suitable management plans to support enforcement of MPA boundaries and the functioning and sustainability of their associated biomass.
... Because some FADs are usually made of non-biodegradable materials, FAD fishing is usually linked to several potential ecological impacts. First, although yet to be determined in the EPO, studies from other oceans suggest that some sharks and sea turtles could get entangled in the webbing material of the FAD (Franco et al. 2009;Hall and Román 2013). Second, lost, abandoned or damaged FADs contribute to the generation of marine debris and pollution. ...
The purse-seine FAD fishery is currently the most important way to capture tropical tunas in the EPO. FADs are a very efficient way of fishing; yet, as most fishing methods, they may also have negative effects on species and ecosystems, such as entanglement of sensitive species, contribution to marine debris and pollution or stranding events in vulnerable habitats. To address these potential effects, the IATTC staff was required to present recommendations based on science that would help in transitioning from traditional to biodegradable FADs, which are expected to reduce those impacts. The European Union granted the IATTC funds for a two-phase project involving experiments with biodegradable non-entangling FADs in both a controlled (phase 1) and real-fishing conditions (phase 2). Phase 1 provided information on the selection of biodegradable materials to be used in the construction of three different prototypes in phase 2. Phase 2’s work plan included several activities, including the design of prototypes (NEDs), the identification of collaborators and participants, the construction of the NEDs, the development and agreement of an experimental design, the monitoring and tracking of the experimental FADs, as well as the data collection and analysis. 379 NEDs (56 prototype 1; 255 prototype 2; 68 prototype 3) have been deployed. Similar values in catch per set (NEDs = 27.7 t/set, paired control FADs = 26 t/set; Table 1) were observed. Prototype 2 showed a very good condition with two months of soak time. Prototype 1 showed a poor condition in the submerged rope, but the rest of materials appeared in good condition after two months at sea. Prototype 3 was the NED design with the least durability observed. The future actions, challenges and solutions of the project as well as ways to engage with the industry and fishers to obtain feedback and guarantee the correct functioning of the project are described as well.
... The former to know the rate of sensitive species entanglement by ghost fishing and the latter to understand the magnitude of beaching events in coastal areas, which has been estimated to be around 10% for the French fleet (Maufroy et al., 2015). Some efforts have already been made to develop an alternative non-entangling FAD in the Pacific (Armstrong and Oliver, 1996), in the Indian (Delgado de Molina et al., 2005), and in the Atlantic Oceans (Franco et al., 2009(Franco et al., , 2012, and some fleets have already started to regularly deploy nonentangling FADs during their commercial fishing trips (Goñi et al., 2015;Goujon et al., 2012;Lopez et al., 2017). Based on this, tuna regional fisheries management organizations (t-RFMOs) have recently adopted several regulations ) that make mandatory the use of non-entangling materials to construct FADs and also encourage the use of biodegradable materials. ...
Despite several ecological and environmental concerns (e.g. increasing marine debris, stranding events), thousands of man-made drifting Fish Aggregating Devices (FADs) are deployed annually by the industrial tuna purse seiners worldwide. Yet, the use of biodegradable materials to construct the underwater part of the FAD has not been explored in detail to date. In this study, scientists, industry, and twine manufacturers collaborate to test and evaluate different potential biodegradable materials and twine designs that can be used in the FAD fishery. Results showed that different materials and designs degrade differently over the study period and that they play an important role in the lifetime of the twines. Results showed that the estimated time to failure (i.e. when breaking strength reaches 0 kgf) ranged between 193 and 557 days for the tested twines. Because twine performance may vary in real fishing tropical conditions, we recommend further experiments in which a new specific twine should be developed and tested: a twisted and bulked cotton, sisal and linen twine. The use of new biodegradable materials and designs are discussed under a global perspective, as well as its implications for conservation, management and relevant future lines of investigation.
... Fish aggregating devices (FADs) also entangle marine species (Franco et al. 2009, Filmalter et al. 2013, Poisson et al. 2014. FADs are often created in conjunction with tuna purse seine fisheries in an attempt to attract fish species into a confined area before encircling them within the purse seine nets (Fonteneau et al. 2000, Ménard et al. 2000. ...
... Of these individuals killed, large numbers are in the first 3 years of their life, indicating juveniles may be significantly impacted (Filmalter et al. 2013). The redesigning of FADs to minimise the use of large quantities of mesh netting is an emerging method in an attempt to reduce entanglement of shark species (Franco et al. 2009, Dagorn et al. 2013, as is the use of sisal ropes and biodegradable materials (Delgado de Molina et al. 2006, Franco et al. 2012, Filmalter et al. 2013. ...
Numerous marine taxa become entangled in anthropogenic marine debris, including cartilaginous fishes (class: Chondrichthyes, e.g. elasmobranchs [sharks, skates and rays], holocephalans [chimaeras]). Here we review research that has been conducted on the susceptibility of these taxa to entanglement in marine debris by conducting a systematic literature review complemented by novel data collection from the social media site Twitter. Our literature review yielded 47 published elasmobranch entanglement events (N = 557 animals) in 26 scientific papers, with 16 different families and 34 species in all 3 major ocean basins affected. The most common entangling objects were ghost fishing gear (74% of animals) followed by polypropylene strapping bands (11% of animals), with other entangling materials such as circular plastic debris, polythene bags and rubber tyres comprising 1% of total entangled animals. Most cases were from the Pacific and Atlantic oceans (49 and 46%, respectively), with a bias towards the USA (44% of animals), the UK (30% of animals) and South Africa (10% of animals). While investigating Twitter, we found 74 cases of elasmobranch entanglement, representing 14 families and 26 species. On Twitter, ghost fishing gear was again the most common entangling material (94.9% of animals), with the majority of entanglement records originating from the Atlantic Ocean (89.4% of total entangled animals). Entanglement in marine debris is symptomatic of a degraded marine environment and is a clear animal welfare issue. Our evidence suggests, however, that this issue is likely a far lesser threat to this taxon than direct or indirect take in marine fisheries. We highlight a relative paucity of scientific data on this subject and recommend a standardisation of reporting in an attempt to accurately quantify elasmobranch entanglement risks and locate interaction hotspots.
