Bottom Longline Research Articles

Longline hook selectivity for whiting (Merlangius merlangus euxinus) with a perspective on small-scale fisheries management in the Black Sea, Türkiye

This study investigated the selectivity parameters of bottom longlines for the Whiting (Merlangius merlangus euxinus) in the small-scale fisheries of the Southeastern Black Sea. Experimental fishing operations were conducted using longlines with hook of 11, 12, 13, and 14mm gaps. A total of 552 fish specimens from four species were captured, with Whiting, the target species, accounting for 90.94% (502 specimens) of the total catch by numbers. The sizes of the Whiting ranged from 10.6 to 20.0 cm Total Length (TL), with a mean size of 15.79 ± 0.087 cm TL. The longline selectivity parameters and curves were fitted using the SELECT method, with the bi-modal model offering the best-fit, based on the lowest deviance value. The modal sizes of specimens caught using the hook of 11, 12, 13, and 14-mm gaps were 12.40, 13.53, 14.66, and 15.78 cm TL, respectively. The modal sizes and spread values increased proportionally with hook size. All the individuals caught by the 14-mm gap hooks exceeded the minimum landing size (MLS) of 13 cm. However, the proportions of individuals below the MLS for the 11, 12, and 13-mm gap hooks were 32.09%, 6.98%, and 0.68%, respectively. Based on the MLS, hooks with gaps larger than 11 mm were found to be highly selective and are recommended for sustainability of the fisheries while ensuring the conservation of immature individuals in the Whiting stocks of the Black Sea. These findings contribute to the much-needed data and information for the design of sound management plans for the small-scale fisheries in the region.

Characterization of Surface and Bottom Longline Artisanal Shark Fisheries in the Northern Gulf of Tehuantepec, Mexico

Characterization of Surface and Bottom Longline Artisanal Shark Fisheries in the Northern Gulf of Tehuantepec, Mexico

Testing best practices in small scale fisheries management: Evidence from a collaborative intervention in two marine protected areas of the central Mediterranean Sea

Adopting best practices (BPs) in small scale fisheries (SSF) is generally acknowledged to enhance ecological and social conditions, improving SSF management overall. Yet studies that empirically assess the effects of BPs on social-ecological outcomes (e.g., fishers' catches, revenues, and level of support towards management measures) remain limited. This study aimed to assess the effects of adopting BPs on catch per unit of effort (CPUE), revenue per unit of effort (RPUE) and small-scale fishers' perceptions in two Marine Protected Areas (MPAs) in Campania, Italy (Santa Maria di Castellabate (CAS-MPA) and Regno di Nettuno (NET-MPA)). Two BPs were implemented and tested in the two MPAs: i) five selective gears with three different mesh/hook sizes and ii) a participatory approach to increase dialogue between fishers and managers. The results from 36 surveys with small scale fishers and 158 SSF operations monitored using photo-sampling and image analysis techniques (between 2020 and 2022) are presented. Analyses of landings showed that significant differences in CPUE and RPUE between mesh/hook sizes were found in a limited number of cases (i.e., combination of fishing gears used in the 2 MPAs). Significant but divergent effects were found on CPUE in the two MPAs for gillnet used to target amberjack (GNA) only. RPUE was significantly higher in the NET-MPA when adopting the largest mesh size for GNA and the largest hook size for bottom longlines (BLL). When analyzing perceptions, fishers generally reported that the BPs adopted had a positive impact on their revenues, improved their relationship with MPA managers and increased their support for the MPA. In addition, eight stakeholder focus groups were held which helped investigators better understand the context, feedback the data gathered from the research and open up dialogue between the relevant stakeholders. The study concluded that increasing mesh/hook sizes, within the range tested here, does not negatively impact fishers’ revenues, while likely improving the status of target populations. Moreover, increasing dialogue between fishers and decision-makers can generate more positive perceptions towards the MPA and improve mutual understanding, helping to reconcile biodiversity conservation with human wellbeing for SSF.

Assessing the vulnerability of sensitive species in Mediterranean fisheries: insights from productivity-susceptibility analysis

Mortality resulting from interactions with fishing gears represent an important threat to sensitive species globally. In this study, we address this issue by defining five species groups of marine megafauna (marine mammals, seabirds, demersal and pelagic elasmobranchs, and sea turtles), and conducting a productivity-susceptibility analysis (PSA) within the context of data-limited fisheries in the Mediterranean and Black Sea. Although there are significant differences among species within each group, this approach has been considered much more direct and functional for management purposes. The productivity (P) of each species group was determined by evaluating a set of attributes averaged across representative species within each group. Species groups’ susceptibility (S) to bycatch was assessed through a comprehensive review of existing literature and expert judgment, considering a series of semi-quantitative attributes. Our analysis identified areas and fishing gears posing potential risks to the species groups assessed, highlighting that sea turtles and elasmobranchs face the potential risk of incidental captures from various fishing gears operating in both neritic (bottom trawls, set nets and bottom longlines) and pelagic (drifting longlines) environments. Marine mammals exhibit moderate risk across most fishing gears, with particular concern for the harbour porpoise Phocoena phocoena relicta in the Black Sea, primarily due to the interaction with set nets, which can severely impact entire population even capturing few specimens due the species low productivity. Seabirds face reduced impact with fishing activities, irrespective of the type of gear examined or the specific area under investigation. Overall, our study highlights the specific basins and fishing gears requiring focused management measures, mitigation strategies, and enhanced monitoring activities to mitigate the impacts of bycatch on vulnerable marine megafauna.

Bycatch mitigation for commonly caught shark species in the Gulf of Mexico reef bottom longline fishery

AbstractObjectiveThe Gulf of Mexico (GOM) reef bottom longline fishery typically not only targets groupers and snappers but also interacts with 27 species of sharks, which are primarily discarded as bycatch. Slow growth, late maturity, and low fecundity in a landscape of increasing fishing pressure make sharks comparatively more susceptible to overfishing and endangered status than other fishes. The purpose of this study was to determine which gear and/or environmental variables best predict the shark catch per set for commonly caught shark species in the GOM reef bottom longline fishery.MethodsWe considered 12 commonly caught shark species that vary from the abundant Atlantic Sharpnose Shark Rhizoprionodon terraenovae to the critically endangered Scalloped Hammerhead Sphyrna lewini. Catch per set, effort, gear, and environmental data were taken from the National Oceanic and Atmospheric Administration National Marine Fisheries Service observer dataset for the GOM reef bottom longline fishery (2009–2017) and were used to fit generalized additive models. The Bayesian information criterion and 10‐fold cross‐validation were used to select the best set of variables that predicted catch per set to determine gear configurations, fisher activities, and environmental conditions contributing to higher shark catch per unit effort. We modeled each species individually, all species combined, and species grouped by similar ecology.ResultGear and fishing method variables were consistently included in the best predictive models across species and were the only potential basis for a single strategy that could decrease bycatch across all 12 species. Patterns of environmental variables were only consistent across species with similar ecology and habitat.ConclusionSharks as a group should not be lumped together, as the effects of mitigation measures become confounded and directly managing trade‐offs between species when minimizing bycatch becomes impossible. Focusing on gear rather than environmental variables is the best apparent option to potentially reduce shark catch per set across commonly caught species while minimizing trade‐offs.

First records of two species of snake eels, Aplatophis chauliodus and Ophichthus hyposagmatus (Actinopterygii: Anguilliformes: Ophichthidae), from Mexico

We report herewith the presence of two species of rare snake eels, Aplatophis chauliodus Böhlke, 1956 (499 mm in total length [TL]) and Ophichthus hyposagmatus McCosker et Böhlke, 1984 (486 mm TL), in Mexican waters of the Gulf of Mexico. Both species were caught using bottom longline at a depth of 50 to 100 m in sandy bottoms in Veracruz, Mexico. Both records are the first for Mexico and the westernmost in the Gulf of Mexico.

Niche structure and habitat shifts for coastal sharks of the US Southeast Atlantic and Gulf of Mexico

AbstractUnderstanding spatial ecology and predicting animal movements in response to environmental changes, such as anthropogenic climate change and multidecadal variability, is critical for effective conservation strategies. Niche structuring is key to some coastal shark species and size classes coexisting in the US Atlantic and Gulf of Mexico to limit interspecific and intraspecific interaction. Data from four fishery‐independent bottom longline surveys were used to evaluate the abiotic ecological niches of eight species of small and large coastal sharks. Gaussian mixture models separated length composition data into 14 size categories for ecological niche analysis. Generalized additive mixed effect models were fit and coupled with output from dynamic high‐resolution ocean models to predict suitable abiotic habitats, evaluate potential shifts in distribution, and explore the impacts of large‐scale climatological trends on abiotic habitats from 1994 to 2019. The abiotic niche for small coastal sharks generally tended toward warmer, high salinity, shallow bottom waters close to shore. No overarching niche was found for large coastal sharks, but appreciable ontogenetic differences were seen. Most taxa analyzed exhibited declining annual trends in higher quality habitats, particularly during fall months. The analysis provided evidence of shifts north along the Atlantic, to deeper offshore waters in the Atlantic and Gulf of Mexico, and the potential to redistribute in response to multidecadal climate variability for multiple species. The analytical framework described could aid in developing various spatiotemporal management measures, and results provide insight into the habitat characteristics of several species over broad spatiotemporal ranges and through ontogeny.

Post‐release mortality of line‐caught snapper Chrysophrys auratus depends on hook site and capture depth

AbstractCatch‐and‐release angling is common in recreational fisheries, but post‐release mortality (PRM) may be high. We conducted a controlled field experiment to estimate mortality of released snapper Chrysophrys auratus. Recreational fishers caught 960 snapper from three depth strata (<15, 15–25, 26–40 m) that were either lip‐hooked, foul‐hooked or gut‐hooked. A bottom longline vessel caught 162 lip‐hooked fish in shallow water to serve as controls. Fish were held in 15‐m deep holding nets. All control fish and 80% of treatment fish survived, with anatomical hook site and capture depth significantly predicting mortality. Probability of mortality was lowest for lip‐hooked fish in shallow water (5 m = 0.00, 95% CI [0.00, 0.03]), but increased rapidly to 20 m (0.24, 95% CI [0.2, 0.3]). Mortality of foul‐hooked fish increased steadily with depth from 0.05 (95% CI [0.00, 0.78]) at 5 m to 0.65 (95% CI [0.13, 0.96]) at 40 m. Gut‐hooking resulted in high mortality at all depths but a low sample size resulted in high uncertainty of estimates. Our results indicate that snapper PRM can be reduced by fishing in shallow water and by mitigating gut‐hooking, possibly by using large circle hooks.

On the biology of blackbellied angler, Lophius budegassa Spinola, 1807, in the north-western Mediterranean

In the Mediterranean Sea, the blackbellied angler, Lophius budegassa Spinola, 1807, represents a relevant fraction of the commercial by-catch of bottom trawling and small-scale fisheries that use passive gears (e.g., set nets, bottom longlines, etc.). Despite its importance, there are no comprehensive studies on the population dynamics of this species, and there is still scarce and scattered knowledge of its biology and ecology. Biomass, morphometric, and biological data of the blackbellied angler were collected from 1994 to 2021 by means of the Mediterranean International Bottom Trawl Survey (MEDITS) programme in the Ligurian and northern Tyrrhenian Seas, and in the EU Data Collection Framework during the period of 2006-2021. Furthermore, ageing was performed on specimens collected from 2013 to 2021 during the MEDITS programme. There were high values for the density indices and the spatial distribution of biomass in the central sector of the investigated area (the Tuscan Archipelago), mostly on the continental shelf. The length-weight relationship showed negative allometric growth when considering the sexes together, and no difference between the sexes. The size at first maturity (L50) was estimated at 39.4 cm total length (TL) in females and at 29.2 cm TL in males. The obtained Von Bertalanffy growth parameters were: in females, L∞ = 74.50 cm, k = 0.10 years-1, and t0 = -0.40 years; in males, L∞ = 61.30 cm, k = 0.14 years-1, and t0 = -0.38 years. There were differences in growth between males and females for L∞ (χ2 = 10.04; p < 0.05) and k (χ2 = 6.12; p < 0.05).

Employing an innovative underwater camera to improve electronic monitoring in the commercial Gulf of Mexico reef fish fishery.

Vessel electronic monitoring (EM) systems used in fisheries around the world apply a variety of cameras to record catch as it is brought on deck and during fish processing activities. In EM work conducted by the Center for Fisheries Electronic Monitoring at Mote (CFEMM) in the Gulf of Mexico commercial reef fish fishery, there was a need to improve upon current technologies to enhance camera views for accurate species identification of large sharks, particularly those that were released while underwater at the vessel side or underneath the hull. This paper describes how this problem was addressed with the development of the first known EM system integrated underwater camera (UCAM) with a specialized vessel-specific deployment device on a bottom longline reef fish vessel. Data are presented based on blind video reviews from CFEMM trained reviewers of the resulting UCAM video footage compared with video from only the overhead EM cameras from 68 gear retrievals collected from eight fishing trips. Results revealed that the UCAM was a successful tool for capturing clear underwater video footage of released large (>2m) sharks to enable reviewers to improve individual species identification, determination, and fate by 34.4%. This was particularly important for obtaining data on incidental catches of large protected shark species. It also provided clear underwater imagery of the presence of potential predators such as marine mammals close to the vessel, more specifically bottlenose dolphin (Tursiops truncatus) during gear retrieval, which often damaged or removed catch. This information is intended to assist researchers in need of gathering critical data on bycatch in close proximity to a vessel in which conventional overhead EM cameras are limited.

Reef Fish in the Vitória-Trindade Seamount Chain of the Southwestern Atlantic: Biogeographical Corridors and Impact of Fishing

This paper aimed to study the community structure of large reef fish off the central coast of Brazil by defining the spatial distribution patterns of 34 species in the outer shelf (50 to 100 m) between 13 and 22ºS, including sea banks, seamounts and the Trindade Island, seeking further to interpret these patterns in light of biogeographic knowledge. In addition, this study attempted to estimate the impact of fishing on the community in different regions using mean weight and size distribution data. The data were obtained in four exploratory fishing surveys of demersal resources employing a bottom longline with steel wire under the aegis of the REVIZEE Program between 1996 and 1998. The numerical abundances were standardised in catch-per-unit-effort (CPUE) in number, and species matrices per station were subjected to detrended correspondence analysis (DCA) and cluster analysis. Reef fauna in the southwestern Atlantic can be divided, in its continental margin, into a tropical component and a subtropical component from latitude 19ºS, which corresponds to the Southern limit of the Abrolhos Bank. North of 19ºS, four distribution patterns were identified (North, Abrolhos, Banks and Trindade). The similarity between the last three enabled the definition of an “Abrolhos-Trindade faunal complex”. Evidence of the impact of commercial fishing on the structure of reef communities was found through differences in the sizes of species studied, which may have occurred differently in each one of the regions of the Abrolhos-Trindade complex. The results also reinforce the importance of the need for conservation measures in these areas.

Taking the bait: Environmental factors affecting bait retention and hook disposition in the Gulf of Maine Bottom Longline Survey

Longline fishery surveys are major contributors to groundfish species abundance estimates. Catchability is often assumed constant, but bait is lost or consumed at inconsistent rates during and across gear sets. Accounting for hook availability and gear saturation can improve abundance estimates, but these data are challenging to collect. Our objectives were to determine whether video camera systems can be used to collect these data from the Northeast Fisheries Science Center’s Gulf of Maine Bottom Longline Survey and to explore the associations between hook disposition percentages and environmental characteristics. Electronic monitoring camera systems were deployed on partner vessels during two fall and two spring seasons to capture video of gear retrieval. During post-survey review, individual hooks were recorded as one of the following hook dispositions: bait, empty hook, fish, and invertebrate. Percentages of these hook dispositions were characterized across categorical (season, day or night, and bottom substrata) and continuous (bottom temperature, bottom depth, and substrate rugosity) survey station variables. Nonmetric multidimensional scaling and logistic regression analyses revealed correlations between retained bait and low bottom temperatures, the spring season, shallow depths, rough bottom substrata, and high terrain rugosity. These characteristics were typical of shallow, inshore, and topographically variable survey strata, suggesting that catchability differs among habitat types. This information will be incorporated into catch rate models to develop standardized indices of abundance for groundfish stock assessments. This study is an example of the utility of electronic technologies to supplement on board data collection during cooperative fishery surveys.

РОГАТКОВЫЕ (COTTIDAE) РЫБЫ ЗАПАДНОКАМЧАТСКОГО ШЕЛЬФА, СОВРЕМЕННОЕ СОСТОЯНИЕ ИХ ПРОМЫСЛА И ПЕРЕРАБОТКИ

The work is devoted to the long-term monitoring of Cottidae fishing which inhabit the shelf off the western coast of Kamchatka (Sea of Okhotsk). According to the results of marine scientific expeditions carried out in different seasons of the year the estimates of the catch (by-catch) of gobies by fishing gear are given. The proportion of fish that is not taken into account in official statistics in bottom longline fishing is estimated. Possible prospects and directions of use of the studied objects of fishing are shown.

Untangling the Complexity of Small-Scale Fisheries: Building an Understanding of Grouper-Snapper Fisheries Dynamics in Saleh Bay, West Nusa Tenggara, Indonesia

Small-scale tropical fisheries are complex systems that utilize multiple fishing gears to target various species. In this study, we investigated small-scale reef and demersal fisheries in Saleh Bay, Indonesia, using catch and effort data from 2016 to 2019, where 57.7 percent of the catch was grouper (serranids) and snapper (lutjanids). Despite the complexity (75 documented species and eight fishing methods), this fishery is characterized by the catches of four dominant species: leopard coral grouper (Plectropomus leopardus), orange-spotted-grouper (Epinephelus coioides), spotted coral grouper (P. maculatus), and malabar blood snapper (Lutjanus malabaricus). The species caught varied among fishing methods. Over 90% of the catch was attributed to three primary fishing methods: bottom longline, speargun, and handline. Multivariate analyses found that fishing depth, season, and/or year significantly influenced the catch composition for each of these fishing methods. Fishing activities exhibit a temporal pattern influenced by monsoonal seasons. Results also suggest that fishers employ specialized fishing tactics by targeting high-value species to maximize their profits. This study recommends a management strategy of focusing on monitoring and managing the three main fishing gears and four important species during their peak seasons to reduce some of the complexity and management costs.

Cumulative ecosystem pressures exerted by demersal fisheries in the Brazilian Meridional Margin: Hotspots and refuges

Demersal fishing operations exert, cumulatively, at least three forms of pressures over the benthic environment: mortality of megafauna (landed and discarded), discards of carrion back to the marine environment (also referred to as Predictable Anthropogenic Food Subsidies - PAFS) and disturbance of the seabed, by contact with bottom gear. This study presents a spatial synthesis of these forms of pressure on the Brazilian Meridional Margin (BMM, SW Atlantic) and their accumulated effect, in contribution to the development of effective space-based fishing management strategies. We analyzed landed catch, discards and effort of 2,125 fishing trips of industrial vessels operating double-rig trawlers, pair trawlers, stern trawlers, bottom longline and gillnets, monitored during 2018 in the main fishing harbors of Southern and Southeastern Brazil. All forms of pressure and the Accumulated Pressure Index (API) were represented spatially in a 20 × 20 nautical mile quads mesh grid. We demonstrated that nearly half of the BMM area was under high pressure. We also delimited fishing pressure hotspots in coastal and shelf areas mostly within the ‘Brazilian Bight’ region, between São Paulo and Santa Catarina states (24–29°S). Conversely, slope regions were found to be less demanded by demersal fishing, with both benthic ecosystems and demersal populations being barely disturbed. These were regarded as the main refuge areas for benthic and benthopelagic megafauna. Double-rig trawling was a major driver of pressure accumulating over half of total number of demersal fishing trips in 2018. Individual double-rig trawling operations also disturbed a seabed area far greater than the areas disturbed by the other fishing gear, and discarded the largest fraction (∼48%) of the produced mortality. Reducing the demersal fishing pressure on the BMM seems to be primarily concerned with abating the intensity of double-rig trawling, and/or diluting their effect through spatial management measures.

First assessment of circle hooks as bycatch mitigation measure for deep-water sharks on longline fisheries

The recognition that deep-water sharks are among the most vulnerable marine species to fisheries exploitation led to the implementation of fishing prohibition regulations in European waters. Reducing unwanted bycatch and mortality are key fisheries mitigation measure for the conservation of these species. Yet, few studies have investigated how to mitigate the common bycatch of these sharks on deep-water longline fisheries. Specifically, the potential of hook type as such a measure has never been investigated. Here, we conducted fishing experiments to test how circle hooks affect the catchability, the hooking position, and the overall condition of deep-water sharks, in comparison to the commonly used J-hooks in the Azores bottom longline fishery. We found that circle hooks did not significantly reduce deep hooking (throat or gut hooked), nor improve the overall condition of captured sharks, while the catchability of deep-water sharks on circle hooks was greater than on the J-hooks currently used in the local fishery. As such, circle hooks do not appear as a suitable measure to reduce deep-water shark bycatch and increase survival potential in deep-water longlining. Despite deep hooking being rare for the deep-water sharks caught with both hook types in the experiments, at-vessel mortality was still substantial (around 40%). Post-release survival remains mostly unquantified but preliminary results suggest it could also be high. This study highlights the urgent need for continued research addressing bycatch mitigation measures for deep-water sharks and identifying efficient strategies to reduce bycatch and increase survival.

Impact of Hermodice carunculata (Pallas, 1766) (Polychaeta: Amphinomidae) on artisanal fishery: A case study from the Mediterranean sea

Invasive species can cause severe economic damages, ecosystem alterations, and can even threat human health. In the global warming scenario, which can act as a driving force for the expansion of thermophilic species, we investigated for the first time the economic damage caused by the invasive bearded fireworm, Hermodice carunculata, to artisanal longline fishery in the Mediterranean Sea. We focused on bottom longline fishery targeting the highly prized white seabream Diplodus sargus, investigating catch composition of the fishing gear and Catch Per Unit Effort (CPUE) of species caught, with particular emphasis on the economic damage caused by the bearded fireworm, H. carunculata, in relation to water temperature. Our results clearly indicated direct and indirect economic damage to fishing activities practiced in the southeastern coast of Sicily (Ionian Sea). Type and extent of the damage caused by the invasive worm (H. carunculata) were discussed in relation to temporal scale and overall yields obtained by this traditional artisanal fishery, and some solutions are proposed. However, the actual situation requires special attention because it is expected to worsen in the context of the global warming future scenarios, such that further studies are urgently needed.

Spatial effort displacement in Florida commercial reef fisheries after red tides

Red tides have affected marine and coastal communities for centuries. The effects of red tides on commercial capture fisheries have rarely been evaluated, owing in part to a lack of appropriate data. Leveraging modeled maps of red tide severity, vessel monitoring systems data, and logbook records, we investigated the commercial fisheries impacts of red tide events in Florida during the period 2008–2019. We focused on the bottom longline and vertical line fisheries targeting reef fishes. Red tides were punctuated events peaking at the end of summer, with 2018 and 2019 the most intense years. The total area affected by intense red tides (concentrations> 1,000 cells/L) was 103,483 km2, about the size of the state of Kentucky. Red tides did not have negative effect on fleet-level fisheries metrics such as number of fishing vessels, trips, fishing effort or revenue (generalized mixed effect models, p > 0.5). Fishing effort was, however, displaced from the red tide areas, and fishers avoided areas characterized by intense blooms (zero-inflated negative binomial model, p < 0.001). Follow up of the long-term likely responses of the resource and the catch are needed to fully understand the consequences of red tide events in commercial fisheries in the Gulf of Mexico.

Length-weight Relationship of Five Demersal Fish Species in Guinea Bissau (CE Atlantic)

Length-weight relationships (LWR) were determined for Brotula barbata, Dentex angolensis, Dentex macrophthalmus, Neomerinthe folgori and Scorpaena stephanica using individual fish records collected between July 2002 and January 2003, during a pilot project of experimental fishing over the shelf off Guinea Bissau. Fishes were caught by commercial vessels using bottom longline, measured defrost for the total length (to the lower 0.1 cm) and weighted for the total weight (TW, to the 0.1 g), and sexed. Two new maximum total lengths were registered for Scorpaena stephanica and Neomerinthe folgori, whose LWR b-values corresponded to the limits of the range obtained, between 2.833 and 3.318, respectively. All LWRs were obtained from well-adjusted linear regressions with r2 ≥ 0.90. Data presented herein expand the knowledge base for these species in West Africa, as they have limited or no LWR data available.

Predicting the distribution and abundance of abandoned, lost or discarded fishing gear (ALDFG) in the deep sea of the Azores (North Atlantic)

Abandoned, lost, or discarded fishing gear (ALDFG), represents a significant percentage of the global plastic pollution, currently considered one of the major sources from sea-based activities. However, there is still limited understanding of the quantities of ALDFG present on the seafloor and their impacts. In this study, data on the presence of ALDFG was obtained from a large archive of seafloor video footage (351 dives) collected by different imaging platforms in the Azores region over 15 years (2006–2020). Most ALDFG items observed in the images relate to the local bottom longline fishery operating in the region, and include longlines but also anchors, weights, cables and buoys. A generalized additive mixed model (GAMM) was used to predict the distribution and abundance of ALDFG over the seafloor within the limits of the Azores Exclusive Economic Zone (EEZ) using a suite of environmental and anthropogenic variables. We estimated an average of 113 ± 310 items km−2 (597 ± 756 per km−2 above 1000 m depth), which could imply that over 20 million ALDFG items are present on the deep seafloor of the Azores EEZ. The resulting model identified potential hotspots of ALDFG along the seabed, some of them located over sensitive benthic habitats, such as specific seamounts. In addition, the interactions between ALDFG and benthic organisms were also analysed. Numerous entanglements were observed with several species of large anthozoans and sponges. The use of predictive distribution modelling for ALDFG should be regarded as a useful tool to support ecosystem-based management, which can provide indirect information about fishing pressure and allow the identification of potential high-risk areas. Additional knowledge about the sources, amounts, fates and impacts of ALDFG will be key to address the global issue of plastic pollution and the effects of fishing on marine ecosystems.