Azores Deep-sea Research — Cruise MedWaves 2016

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MedWaves 2016

MEDiterranean out flow WAter and Vulnerable EcosystemS

MedWaves 2016

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MEDiterranean out flow WAter and Vulnerable EcosystemS

Location: Formigas

Year: 2016

10 dives

1 areas visited

AZORES DEEP-SEA RESEARCH

Summary

MEDiterranean out flow WAter and Vulnerable EcosystemS

The primary objective of the MEDWAVES cruise at Formigas Bank was to characterize the physical and biogeochemical properties of the water masses interacting with the seamount and to document the associated benthic communities, particularly vulnerable marine ecosystems (VMEs) like cold-water coral habitats. The work aimed to determine if Formigas acts as an ecological "stepping stone" influenced by the Mediterranean Outflow Water, connecting fauna between the Mediterranean and the Mid-Atlantic. The methodology included high-resolution multibeam mapping, detailed CTD/LADCP profiling to trace the MOW signal, and intensive ROV operations for visual surveys and biological sampling. The results contribute to ATLAS goals of improving understanding of deep Atlantic biodiversity, quantifying ocean transport pathways, and assessing the vulnerability of benthic ecosystems to environmental change.

The MEDWAVES (MEDiterranean out flow WAter and Vulnerable EcosystemS) survey was an EU Horizon 2020 ATLAS project cruise aboard the R/V Sarmiento de Gamboa. Led by Cova Oreja (IEO) it targeted seamounts under the influence of the Mediterranean Outflow Water (MOW). The Formigas Bank in the Azores was one of the study sites. The expedition aimed to characterize the interaction between oceanographic conditions and deep-sea ecosystems, collecting multidisciplinary data through ROV dives (500-1575 m depth), CTD casts, and seabed sampling to understand biodiversity patterns and connectivity.

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Statistics

Transits

Multibeam Bathymetry

2255 km²

Filmed Seabed

11 km

Visited Areas

Stations

Dives

Video Footage Recorded

37 hours

Used Storage

Samples

— We acquired 18 specimens of the bamboo coral *Acanella* sp., plus several samples of *Acanthogorgia* sp., Alcyonacea (small), Antipatharian, *Candidella* sp., *Crypthelia* sp., *Leiopathes* sp., *Swiftia* sp., Plexauridae, *Narella* sp., among other taxa.

Highlights

(Focusing in the Formigas seamount only)

Discovery of highly diverse coral gardens: The expedition documented extensive and dense coral gardens on Formigas Bank, dominated by octocorals like Acanella arbuscula, primnoids (Narella spp., Candidella imbricata), and plexaurids. A key highlight was the first in-situ observation of the bamboo coral Chelidonisis aurantiaca in the Azores, a species previously linked to MOW pathways.
First in-depth characterization of Formigas benthic habitats: Ten ROV dives provided the first comprehensive video survey of the seamount's slopes, revealing distinct megafaunal communities stratified by depth and substrate, from soft-sediment areas with cerianthids and sponges Stylocordyla pellita to steep basaltic walls covered by black corals, scleractinians, and diverse sponge assemblages.
Mapping the influence of Mediterranean Outflow Water: Physical oceanography data confirmed the presence of diluted MOW at Formigas (salinity max ~35.82 at ~1000m), demonstrating its westward transport over 900 nautical miles from the Strait of Gibraltar. Yo-yo CTD casts suggested internal wave activity, a potential mechanism for vertical nutrient supply.
Collection of unique biological samples: The cruise collected 49 benthic samples with the ROV, including numerous octocorals, black corals, and sponges for taxonomic, genetic (connectivity), and ecophysiological studies, building an invaluable reference for North Atlantic deep-sea biodiversity.
Identification of Vulnerable Marine Ecosystem (VME) Indicators: ROV transects identified several potential VMEs, including large aggregations of habitat-forming corals and sponges.
High-resolution bathymetric mapping: New multibeath bathymetry covered approximately 2,256 km² around Formigas, revealing a complex geomorphology of ridges, fractures, and volcanic knolls that directly influences local current regimes and habitat distribution.

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Location of operation

Formigas

AZORES DEEP-SEA RESEARCH © CRUISES

Stations

MedWaves 2016

Activities

Video survey (ROV Liropus) Multibeam

Funding

Regional Government of the Azores, PO Açores 2020, European Regional Development Fund (ERDF / FEDER) ACORES-01-0145-FEDER-00056

European Union’s Horizon 2020 678760 (ATLAS)

Cruise crew

Scientific crew

Gerald Hechter Taranto

Manuela Ramos

Collaborators

Meri Bilan

Maria Rakka

Íris Sampaio

Covadonga Orejas

Anna Addamo

Marta Álvarez

Alberto Aparicio

Daniel Alcoverro

Sophie Arnaud-Haond

Joana Boavida

Verónica Caínzos

Rubén Calderón

Peregrino Cambeiro

Mónica Castaño

Alan Fox

Marina Gallardo

Andrea Gori

Cristina Gutiérrez

Lea-Anne Henry

Miriam Hermida

Juan Antonio Jiménez

José Luis López-Jurado

Pablo Lozano

Ángel Mateo-Ramírez

Guillem Mateu

José Luis Matoso

Carlos Méndez

Ana Morillas

Juancho Movilla

Alejandro Olariaga

Manuel Paredes

Víctor Pelayo

Safo Piñeiro

Teodoro Ramírez

Jesus Reis

Jesús Rivera

Alberto Romero

José Luis Rueda

Toni Salvador

Héctor Sánchez

Rocío Santiago

Alberto Serrano

Javier Urra

Pedro Vélez-Belchí

Nuria Viladrich

Martha Zein

Cruise Summary Report - Medwaves Survey (Mediterranean Out Flow Water And Vulnerable Ecosystems)

Zenodo

Apr, 2017

2 team members are authors

OA Citations 11 DOI 10.5281/zenodo.556516

Authors 10.5281/zenodo.556516

Covadonga Orejas Anna Maria Addamo Marta Álvarez Alberto Martín Aparicio Daniel Alcoverro Sophie Arnaud‐Haond Meri Bilan Joana Boavida Verónica Caínzos Ruben Calderon Peregrino Cambeiro Mónica Duque-Castaño Alan Fox Marina Gallardo Andrea Gori Christina Guitierrez Lea‐Anne Henry Miriam Hermida Juan Antonio Jimenez José Luís López‐Jurado Pablo Lozano Ángel Mateo‐Ramírez Guillem Mateu Mateu Jose Luis Matoso Carlos Mendez A. Morillas-Kieffer Juancho Movilla Alejandro Olariaga Manuel Paredes Victor Pelayo Safo Piñeiro Maria Rakka Teodoro Ramı́rez

Manuela Ramos Jesus Reis J. Rivera Alberto Romero José L. Rueda Toni Salvador Íris Sampaio Héctor Sánchez Rocío Santiago Alberto Serrano

Gerald H. Taranto Javier Urra P. Vélez‐Belchí Núria Viladrich Martha Zein

Related cruises (1)

MedWaves 2016 MEDiterranean out flow WAter and Vulnerable EcosystemS

Abstract

The MEDWAVES (MEDiterranean out flow WAter and Vulnerable EcosystemS) cruise targeted areas under the potential influence of the MOW within the Mediterranean and Atlantic realms. These include seamounts where Cold-water corals (CWCs) have been reported but that are still poorly known, and which may act as essential “stepping stones” connecting fauna of seamounts in the Mediterranean with those of the continental shelf of Portugal, the Azores and the Mid-Atlantic Ridge. During MEDWAVES sampling has been conducted in two of the case studies of ATLAS: Case study 7 (Gulf of Cádiz-Strait of Gibraltar-Alboran Sea) and Case
study 8 (Azores). The initially targeted areas in the Atlantic were: the Gazul Mud volcano, in the Gulf of Cádiz (GoC) area, included in the case study 7, and the Atlantic seamounts Ormonde (Portuguese shelf) and Formigas (by Azores), both part of the case study 8. In the Mediterranean the targeted areas were The Guadiaro submarine canyon and the Seco de los Olivos (also known as Chella Bank) seamount. Unfortunately it was not possible to sample in Guadiaro due to time constraints originated by adverse meteorological conditions which obligate us to reduce the time at sea focusing only in 4 of the 5 initially planned areas. MEDWAVES was structured in two legs; the first leg took place from the 21st September (departure from Cádiz harbour in Spain) to the 13th October 2016 (arrival in Ponta Delgada, São Miguel, Azores, Portugal took place the 8th of October due to the meteorological conditions that obligated to conclude the first leg earlier as planned). during the Leg 1 sampling was carried out in Gazul, Ormonde and Formigas. The second leg started the 14th October (departure from Ponta Delgada) and finished the 26th October (arrival in Málaga harbour, Spain). MEDWAVES had a total of 30 effective sampling days, being 6 days not operative due to the adverse meteorological conditions experienced during the first leg which forced us to stay in Ponta Delgada from the 08th to the 13th October. During MEDWAVES the daily routine followed a similar scheme, depending of course on the weather and sea conditions. The main activity during the day, starting early in the morning (around 08:00 AM, once the night activities were finished), was the ROV deployment. Generally a single ROV dive of around 8 hours was performed, however in several occasions two dives were carried out in the same day (see General station list, Appendix II). After the ROV (and sometimes between two dives) the Box Corer and/or Van Veen Grab and/or Multicore was deployed. After these activities, during the night CTD-Rosette deployments and MB was conducted. Accordingly to this schema the scientific personnel worked in the day or in the night watch. A total of 215 sampling stations have been covered in MEDWAVES, using the following sampling gears: Multibeam echosounder, CTD-Rosette, LADCP, Box Corer, Van Veen Grab, Multicorer and a Remotely Operated Vehicle (ROV). Table 1 sumamrised the number of sampling stations conducted with each gear in each sampling zone. Additionally MB surveys have been conducted during the transits between areas.

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First description of polyp bailout in cold-water octocorals under aquaria maintenance

Coral Reefs

Jan, 2019

2 team members are authors

OA Citations 16 DOI 10.1007/s00338-018-01760-x

Authors 10.1007/s00338-018-01760-x

Maria Rakka Meri Bilan

António Godinho Juancho Movilla Covadonga Orejas

Marina Carreiro‐Silva

Related projects (2)

ATLAS A transatlantic assessment and deep-water ecosystem-based spatial management plan for Europe Funded by European Union’s Horizon 2020

MERCES Marine Ecosystem Restoration in Changing European Seas Funded by European Union’s Horizon 2020

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MedWaves 2016 MEDiterranean out flow WAter and Vulnerable EcosystemS

Census of Octocorallia (Cnidaria: Anthozoa) of the Azores (NE Atlantic) with a nomenclature update

Zootaxa

Jan, 2019

2 team members are authors

OA Citations 20 DOI 10.11646/zootaxa.4550.4.1

Authors 10.11646/zootaxa.4550.4.1

Íris Sampaio André Freiwald

Filipe M. Porteiro Gui M. Menezes

Marina Carreiro‐Silva

Related projects (1)

ATLAS A transatlantic assessment and deep-water ecosystem-based spatial management plan for Europe Funded by European Union’s Horizon 2020

Related cruises (1)

MedWaves 2016 MEDiterranean out flow WAter and Vulnerable EcosystemS

Abstract

Zoological nomenclature revisions are essential for biodiversity studies and indispensable to avoid naming and description of already described species and should be valued in all subsequent studies considering biology, molecular biology, ecology or habitat mapping of deep-sea species. Herein, a thorough revision of the taxonomic literature on Octocorallia since the beginning of deep-sea exploration in the Azores is provided. Since 1870, when the first octocoral, Virgularia mirabilis (Müller, 1776), was recorded in the Azores a cyclic pattern on the taxonomical study of octocorals reveals the deep-sea investigation efforts made on the region at different periods: Prince Albert I of Monaco, Biaçores and recent expeditions. The first decade of this millennium was the peak on taxonomic research of cold-water octocorals in the Azores with 11 publications targeting gorgonians and soft corals (Alcyonacea) and specific sub-orders within it. Ninety-eight names of Octocorallia were found to be given in the economic exclusive zone of the Azores. While 25 names were changed or added to the known Azorean octocoral diversity, 3 species identified in the region and unreported in the reviewed literature, increase the number to 101 species. Twenty-five names were synonymized while three species names were unmasked as errors in need of taxonomical clarification. This is the highest species richness of Octocorallia found in Europe and in any Northern Atlantic archipelago so far, representing ~60% of the most diverse center of endemism of South Africa, with a part in the Eastern Atlantic. Further research on taxonomy may reveal new species to science.

Ocean Circulation Over North Atlantic Underwater Features in the Path of the Mediterranean Outflow Water: The Ormonde and Formigas Seamounts, and the Gazul Mud Volcano

Frontiers in Marine Science

Dec, 2019

3 team members are authors

OA Citations 12 DOI 10.3389/fmars.2019.00702

Authors 10.3389/fmars.2019.00702

Ángela Mosquera Giménez P. Vélez‐Belchí J. Rivera Safo Piñeiro Noelia M. Fajar Verónica Caínzos Rosa Balbín J. A. Aparicio

Carlos Dominguez‐Carrió Jordi Blasco-Ferre

Marina Carreiro‐Silva

Telmo Morato Patricia Puerta Covadonga Orejas

Related projects (1)

ATLAS A transatlantic assessment and deep-water ecosystem-based spatial management plan for Europe Funded by European Union’s Horizon 2020

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MedWaves 2016 MEDiterranean out flow WAter and Vulnerable EcosystemS

Abstract

Seamounts constitute an obstacle to the ocean circulation, modifying it. As a result, a variety of hydrodynamical processes and phenomena may take place over seamounts, among others, flow intensification, current deflection, upwelling, Taylor caps, and internal waves. These oceanographic effects may turn seamounts into very productive ecosystems with high species diversity, and in some cases, are densely populated by benthic organisms, such corals, gorgonians, and sponges. In this study, we describe the oceanographic conditions over seamounts and other underwater features in the path of the Mediterranean Outflow Water (MOW), where populations of benthic suspensions feeders have been observed. Using CTD, LADPC and biochemical measurements carried out in the Ormonde and Formigas seamounts and the Gazul mud volcano (Northeast Atlantic), we show that Taylor caps were not observed in any of the sampled features. However, we point out that the relatively high values of the Brunt–Väisälä frequency in the MOW halocline, in conjunction with the slope of the seamount flanks, set up conditions for the breakout of internal waves and amplification of the currents. This may enhance the vertical mixing, resuspending the organic material deposited on the seafloor and, therefore, increasing the food availability for the communities dominated by benthic suspension feeders. Thus, we hypothesize that internal waves could be improving the conditions for benthic suspension feeders to grow on the slope of seamounts.

Climate‐induced changes in the suitable habitat of cold‐water corals and commercially important deep‐sea fishes in the North Atlantic

Global Change Biology

Feb, 2020

5 team members are authors

OA Citations 216 DOI 10.1111/gcb.14996

Authors 10.1111/gcb.14996

Telmo Morato

José Manuel González‐Irusta

Carlos Dominguez‐Carrió Chih‐Lin Wei Andrew J. Davies Andrew K. Sweetman

Gerald H. Taranto Lindsay Beazley Ana García‐Alegre Anthony Grehan Pascal Laffargue Francisco Javier Murillo M.m. Sacau-Cuadrado Sandrine Vaz Ellen Kenchington Sophie Arnaud‐Haond Oisín Callery Giovanni Chimienti Erik E. Cordes Hrönn Egilsdóttir André Freiwald Ryan Gasbarro Cristina Gutiérrez‐Zárate Matthew Gianni Kent Gilkinson Vonda E. Wareham Hayes Dierk Hebbeln Kevin J. Hedges Lea‐Anne Henry David E. Johnson Mariano Koen‐Alonso Cam Lirette Francesco Mastrototaro Lénàïck Menot Tina N. Molodtsova P. Durán-Muñoz Covadonga Orejas María Grazia Pennino Patricia Puerta Stefán Á. Ragnarsson Berta Ramiro‐Sánchez Jake Rice J. Rivera J. Murray Roberts Steve W. Ross José L. Rueda Íris Sampaio Paul V. R. Snelgrove David Stirling Margaret A. Treble Javier Urra Johanne Vad Dick Van Oevelen Les Watling Wojciech Walkusz Claudia Wienberg Mathieu Woillez Lisa A. Levin

Marina Carreiro‐Silva

Related projects (6)

ATLAS A transatlantic assessment and deep-water ecosystem-based spatial management plan for Europe Funded by European Union’s Horizon 2020

CoralFISH Assessment of the interaction between corals, fish and fisheries, in order to develop monitoring and predictive modelling tools for ecosystem based management in the deep waters of Europe and beyond Funded by European Union’s FP7

DISCARDLESS Startegies for the gradual elimination of discards in European fisheries Funded by European Union’s Horizon 2020

HERMIONE Hotspot Ecosystem Research and Man’s Impact on European Seas

MapGES Mapping deep-sea biodiversity and “Good Environmental Status” in the Azores: assisting with the implementation of EU Marine Strategy Framework Directive Funded by Regional Government of the Azores, PO Açores 2020, European Regional Development Fund (ERDF / FEDER)

MERCES Marine Ecosystem Restoration in Changing European Seas Funded by European Union’s Horizon 2020

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Blue Azores 2018 Blue Azores Program: Expedition 2018

MedWaves 2016 MEDiterranean out flow WAter and Vulnerable EcosystemS

Abstract

The deep sea plays a critical role in global climate regulation through uptake and storage of heat and carbon dioxide. However, this regulating service causes warming, acidification and deoxygenation of deep waters, leading to decreased food availability at the seafloor. These changes and their projections are likely to affect productivity, biodiversity and distributions of deep-sea fauna, thereby compromising key ecosystem services. Understanding how climate change can lead to shifts in deep-sea species distributions is critically important in developing management measures. We used environmental niche modelling along with the best available species occurrence data and environmental parameters to model habitat suitability for key cold-water coral and commercially important deep-sea fish species under present-day (1951-2000) environmental conditions and to project changes under severe, high emissions future (2081-2100) climate projections (RCP8.5 scenario) for the North Atlantic Ocean. Our models projected a decrease of 28%-100% in suitable habitat for cold-water corals and a shift in suitable habitat for deep-sea fishes of 2.0°-9.9° towards higher latitudes. The largest reductions in suitable habitat were projected for the scleractinian coral Lophelia pertusa and the octocoral Paragorgia arborea, with declines of at least 79% and 99% respectively. We projected the expansion of suitable habitat by 2100 only for the fishes Helicolenus dactylopterus and Sebastes mentella (20%-30%), mostly through northern latitudinal range expansion. Our results projected limited climate refugia locations in the North Atlantic by 2100 for scleractinian corals (30%-42% of present-day suitable habitat), even smaller refugia locations for the octocorals Acanella arbuscula and Acanthogorgia armata (6%-14%), and almost no refugia for P. arborea. Our results emphasize the need to understand how anticipated climate change will affect the distribution of deep-sea species including commercially important fishes and foundation species, and highlight the importance of identifying and preserving climate refugia for a range of area-based planning and management tools.

Influence of Water Masses on the Biodiversity and Biogeography of Deep-Sea Benthic Ecosystems in the North Atlantic

Frontiers in Marine Science

Apr, 2020

3 team members are authors

OA Citations 83 DOI 10.3389/fmars.2020.00239

Authors 10.3389/fmars.2020.00239

Patricia Puerta Clare Johnson

Marina Carreiro‐Silva Lea‐Anne Henry Ellen Kenchington

Telmo Morato Georgios Kazanidis José Luis Rueda Javier Urra Steve Ross Chih‐Lin Wei

José Manuel González‐Irusta Sophie Arnaud‐Haond Covadonga Orejas

Related projects (2)

ATLAS A transatlantic assessment and deep-water ecosystem-based spatial management plan for Europe Funded by European Union’s Horizon 2020

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MedWaves 2016 MEDiterranean out flow WAter and Vulnerable EcosystemS

Abstract

Circulation patterns in the North Atlantic Ocean have changed and re-organized multiple times over millions of years, influencing the biodiversity, distribution and connectivity patterns of deep-sea species and ecosystems. In this study, we review the effects of the water mass properties (temperature, salinity, food supply, carbonate chemistry and oxygen) on deep-sea benthic megafauna (from species to community level) and discussed in future scenarios of climate change. We focus on the key oceanic controls on deep-sea megafauna biodiversity and biogeography patterns. We place particular attention on cold-water corals and sponges, as these are ecosystem-engineering organisms that constitute vulnerable marine ecosystems with high associated biodiversity. Besides documenting the current state of the knowledge on this topic, a future scenario for water mass properties in the deep North Atlantic basin was predicted. The pace and severity of climate change in the deep-sea will vary across regions. However, predicted water mass properties showed that all regions in the North Atlantic will be exposed to multiple stressors by 2100, experiencing at least one critical change in water temperature (+2°C), organic carbon fluxes (reduced up to 50 %), ocean acidification (pH reduced up to 0.3), aragonite saturation horizon (shoaling above 1000 m) and/or reduction in dissolved oxygen (5%). The northernmost regions of the North Atlantic will suffer the greatest impacts. Warmer and more acidic oceans will drastically reduce the suitable habitat for ecosystem-engineers, with severe consequences such as declines in population densities, even compromising their long-term survival, loss of biodiversity and reduced biogeographic distribution that might compromise connectivity at large scales. These effects can be aggravated by reductions in carbon fluxes, particularly in areas where food availability is already limited. Declines in benthic biomass and biodiversity will diminish ecosystem services such as habitat provision, nutrient cycling, etc. This study shows that the deep-sea vulnerable marine ecosystems affected by contemporary anthropogenic impacts and with the the ongoing climate change impacts are unlikely to withstand additional pressures from more intrusive human activities. This study serves also as a warning to protect these ecosystems through regulations and by tempering the ongoing socio-political drivers for increasing exploitation of marine resources.

Variability of deep-sea megabenthic assemblages along the western pathway of the Mediterranean outflow water

Deep Sea Research Part I Oceanographic Research Papers

May, 2022

3 team members are authors

OA Citations 16 Rising DOI 10.1016/j.dsr.2022.103791

Authors 10.1016/j.dsr.2022.103791

Patricia Puerta Ángela Mosquera-Giménez Olga Reñones

Carlos Dominguez‐Carrió José L. Rueda Javier Urra

Marina Carreiro‐Silva Jordi Blasco-Ferre Yaiza Santana Cristina Gutiérrez‐Zárate P. Vélez‐Belchí J. Rivera

Telmo Morato Covadonga Orejas

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ATLAS A transatlantic assessment and deep-water ecosystem-based spatial management plan for Europe Funded by European Union’s Horizon 2020

DeepWalls Exploring pristine deep-sea walls to establish baselines for Good Environmental Status in the Azores Funded by Regional Government of the Azores, PO Açores 2020, European Regional Development Fund (ERDF / FEDER)

iAtlantic Integrated Assessment of Atlantic Marine Ecosystems in Space and Time Funded by European Union’s Horizon 2020

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MedWaves 2016 MEDiterranean out flow WAter and Vulnerable EcosystemS

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

The Science of The Total Environment

Aug, 2023

9 team members are authors

OA Citations 19 Rising DOI 10.1016/j.scitotenv.2023.166579

Authors 10.1016/j.scitotenv.2023.166579

Emily M. Duncan Nina Vieira

José Manuel González‐Irusta

Carlos Dominguez‐Carrió

Telmo Morato

Marina Carreiro‐Silva Joachim Jakobsen Kirsten Jakobsen

Filipe M. Porteiro Nina Schläpfer Laura Herrera

Manuela Ramos

Yasmina Rodríguez João Pereira

Laurence Fauconnet

Luís Rodrigues Hugo Parra Christopher K. Pham

Related projects (3)

ATLAS A transatlantic assessment and deep-water ecosystem-based spatial management plan for Europe Funded by European Union’s Horizon 2020

iAtlantic Integrated Assessment of Atlantic Marine Ecosystems in Space and Time Funded by European Union’s Horizon 2020

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Blue Azores 2018 Blue Azores Program: Expedition 2018

MapGES 2019 Mapping deep-sea biodiversity and “Good Environmental Status” in the Azores

MedWaves 2016 MEDiterranean out flow WAter and Vulnerable EcosystemS

NICO Leg 12 2018 RV Pelagia cruise 64PE441: Rainbow hydrothermal vent, southern MAR, and Terceira 2018

Rainbow 2019 RV Pelagia cruise 64PE454: Rainbow hydrothermal vent and southern MAR 2019

Abstract

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.

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