Azores Deep-sea Research — Cruise MedWaves 2016

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)

Scientific crew

Manuela Ramos

PhD Student

Gerald Hechter Taranto

Early-career Researcher

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

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North Atlantic basin-scale multi-criteria assessment database to inform management recommendations to protect Vulnerable Marine Ecosystems

Nov, 2020

7 team members are authors

OA DOI 10.5281/zenodo.4279776

Authors 10.5281/zenodo.4279776

Telmo Morato Christopher K. Pham

Laurence Fauconnet

Gerald H. Taranto Giovanni Chimienti Erik E. Cordes

Carlos Dominguez‐Carrió P. Durán-Muñoz Hrönn Egilsdóttir José Manuel González‐Irusta Anthony Grehan Dierk Hebbeln Lea‐Anne Henry Georgios Kazanidis Ellen Kenchington Lénàïck Menot Tina N. Molodtsova Covadonga Orejas Berta Ramiro‐Sánchez

Manuela Ramos

Luís Rodrigues Steve W. Ross José L. Rueda M.m. Sacau-Cuadrado David Stirling

Marina Carreiro‐Silva

Abstract

We applied the International Council for the Exploration of the Sea (ICES) multi criteria assessment (MCA) method for identifying VMEs in the North-East Atlantic (ICES, 2016a,b; Morato et al., 2018) from ATLAS VME database to provide the first North Atlantic Ocean basin-scale VME assessment. This MCA is a taxa-dependent spatial method that incorporates the fact that not all VME indicators have the same vulnerability to human impacts, and thus should not be weighted equally. By including a measure of the confidence associated with each VME record, this methodology also considers some of the uncertainties associated with the sampling methodologies, the reported taxonomy, and data quality issues. Equally important, this dataset highlights areas in the North Atlantic that have been poorly sampled and that require further attention. Finally, this methodology also allows for the evaluation and comparison of the VME likelihood with spatial fisheries data that may directly generate significant adverse impacts on VMEs. In the data report, we made the “North Atlantic basin-scale VME index dataset” publicly, thus allowing its consultation and use by scientists, managers, or other relevant stakeholders.

GIS layers of seafloor characteristics in the Azores region (North Atlantic), links to files in ArcGIS format

Jan, 2016

1 team member is author

OA Citations 1 DOI 10.1594/pangaea.862152

Authors 10.1594/pangaea.862152

Antonio David Perán Miñarro Christopher K. Pham Patrícia Amorim Frederico Cardigos Fernando Tempera

Telmo Morato

Abstract

Current European legislation such as the Marine Strategy Framework Directive (MSFD; 2008/56/EC) has highlighted the need for accurate maps on the geomorphology of Europe's maritime territory. Such information is notably essential for the production of habitat maps and cumulative impact assessments of human activities (Halpern et al., 2008) necessary for marine spatial planning initiatives (Gilliland and Laffoley, 2008) and assessments of the representativity/sufficiency of marine protected areas networks like Natura 2000. Broadscale satellite bathymetry presently allows the identification of all prominent geomorphic structures present on the seafloor with a high grade of accuracy. However, these datasets and maps still need to be more widely disseminated in the scientific community.In this contribution, we provide an inventory of some important datasets related to the physical characteristics of the seafloor surrounding the Azores Archipelago. The objective is to ensure that our compilation is readily available for any researchers interested in developing species distribution models, or for the management and conservation of natural resources in the region.

Ocean climatology in the Azores region (North Atlantic) and seabed characteristics, links to GIS layers in ArcGIS format

Jan, 2017

1 team member is author

OA DOI 10.1594/pangaea.872601

Authors 10.1594/pangaea.872601

Patrícia Amorim António D. Perán Christopher K. Pham Manuela Juliano Frederico Cardigos Fernando Tempera

Telmo Morato

Abstract

Obtaining a comprehensive knowledge of the spatial and temporal variations of the environmental factors characterizing the Azores region is essential for conservation and management purposes. Although many studies are available for the region, there is a need for a general overview of the best available information. Here, we assembled a comprehensive collection of environmental data for this region. Data sources used in this study included remote sensing oceanographic data for 2003?2013 (sea surface temperature, chlorophyll-a concentration, particulate inorganic carbon (PIC), and particulate organic carbon (POC)), derived oceanographic data (primary productivity and North Atlantic oscillation index) for 2003?2013, and in situ data (temperature, salinity, oxygen, phosphate, nitrate and silicate) obtained from the World Ocean Atlas 2013.

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

Jan, 2019

3 team members are authors

OA Citations 2 DOI 10.1594/pangaea.910319

Authors 10.1594/pangaea.910319

Morato, Telmo González-Irusta, José Manuel Domínguez-Carrió, Carlos Wei, C Davies, A Sweetman, Andrew K

Taranto, A H Beazley, Lindsay García-Alegre, A Grehan, Anthony J Laffargue, P Javier Murillo, F Sacau, M Vaz, S Kenchington, Ellen L Arnaud-Haond, Sophie Callery, Oisín Chimienti, G Cordes, E Egilsdottir, Hronn Freiwald, André Gasbarro, R Gutierrez-Zárate, C Gianni, M Gilkinson, Kent Wareham Hayes, V E Hebbeln, Dierk Hedges, K Henry, Lea Anne Johnson, Devin S Koen-Alonso, M Lirette, C Mastrototaro, F Menot, Lenaick Molodtsova, Tina Durán Muñoz, P Orejas, Covadonga Pennino, Maria Grazia Puerta, P Ragnarsson, Stefan Aki Ramiro-Sánchez, Berta Rice, J Rivera, Jaime Roberts, J Murray Ross, Steve W Rueda, José Luis Sampaio, Íris Snelgrove, Paul V R Stirling, David Treble, M A Urra, Javier Vad, Johanne Van Oevelen, Dick Watling, L Walkusz, Wojciech Wienberg, Claudia Woillez, M Levin, L A

Carreiro-Silva, Marina

Abstract

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 forecast changes under severe, high emissions future (2081-2100) climate projections (RCP8.5 scenario) for the North Atlantic Ocean (from 18°N to 76°N and 36°E to 98°W). The VME indicator taxa included Lophelia pertusa , Madrepora oculata, Desmophyllum dianthus, Acanela arbuscula, Acanthogorgia armata, and Paragorgia arborea. The six deep-sea fish species selected were: Coryphaenoides rupestris, Gadus morhua, blackbelly Helicolenus dactylopterus, Hippoglossoides platessoides, Reinhardtius hippoglossoides, and Sebastes mentella. We used an ensemble modelling approach employing three widely-used modelling methods: the Maxent maximum entropy model, Generalized Additive Models, and Random Forest. This dataset contains: 1) Predicted habitat suitability index under present-day (1951-2000) and future (2081-2100; RCP8.5) environmental conditions for twelve deep-sea species in the North Atlantic Ocean, using an ensemble modelling approach. 2) Climate-induced changes in the suitable habitat of twelve deep-sea species in the North Atlantic Ocean, as determined by binary maps built with an ensemble modelling approach and the 10-percentile training presence logistic (10th percentile) threshold. 3) Forecasted present-day suitable habitat loss (value=-1), gain (value=1), and acting as climate refugia (value=2) areas under future (2081-2100; RCP8.5) environmental conditions for twelve deep-sea species in the North Atlantic Ocean. Areas were identified from binary maps built with an ensemble modelling approach and two thresholds: 10-percentile training presence logistic threshold (10th percentile) and maximum sensitivity and specificity (MSS). Refugia areas are those areas predicted as suitable both under present-day and future conditions. All predictions were projected with the Albers equal-area conical projection centred in the middle of the study area. The grid cell resolution is of 3x3 km.

ATLAS work on Good Environmental Status across 9 study areas in the northeast Atlantic

Jan, 2020

2 team members are authors

OA DOI 10.1594/pangaea.911409

Authors 10.1594/pangaea.911409

Kazanidis, Georgios Orejas, Covadonga Borja, Angel Kenchington, Ellen L Henry, Lea-Anne Callery, Oisín

Carreiro-Silva, Marina Egilsdottir, Hronn Giacomello, Eva Grehan, Anthony J Menot, Lenaick

Morato, Telmo Ragnarsson, Stefan Aki Rueda, José Luis Stirling, David Stratmann, Tanja Van Oevelen, Dick Palialexis, Andreas Johnson, David Roberts, J Murray

Abstract

This data is showing the outcomes of the analysis done by ATLAS researchers on the environmental status of nine deep-sea areas in the northeast Atlantic. These results are part of the ATLAS work facilitating the implementation of the European Commission's Marine Strategy Framework Directive in the deep waters of the North Atlantic. The nine study areas that were examined are: 1) LoVe Ocean Observatory, 2) Faroe-Shetland Channel, 3) Reykjanes Ridge, 4) Rockall Bank, 5) Mingulay Reef Complex, 6) Porcupine Seabight, 7) Bay of Biscay, 8) Azores, 9) Gulf of Cádiz. The analyses were carried out using the Nested Environmental status Assessment Tool (NEAT). The environmental status outcomes are shown for the total study area, the designated spatial assessment units (SAUs), the ecosystem components ("Benthic invertebrates", "Fish", "Benthos") and the habitats ("Aggregations of L. pertusa & M. oculata on soft sediments", "Aggregations of sea pens & alcyonaceans on soft sediments", "Aggregations of L. pertusa & M. oculata on hard substrates", "Aggregations of Antipatharians and alcyonaceans on hard substrates", "Benthic", "Rocky", "Sedimentary").

Compilation of records of vulnerable marine ecosystem indicator taxa in the North Atlantic

Jan, 2020

3 team members are authors

OA DOI 10.1594/pangaea.920658

Authors 10.1594/pangaea.920658

Ramiro-Sánchez, Berta Henry, Lea-Anne

Morato, Telmo

Taranto, Gerald Cleland, Jason

Carreiro-Silva, Marina Sampaio, Íris Domínguez-Carrió, Carlos Messing, Charles G Kenchington, Ellen L Murton, Bramley Roberts, J Murray

Abstract

Obtaining a comprehensive knowledge of the spatial variation of deep-sea benthic ecosystems is essential for conservation and management purposes. Here we assembled publicly available information on the positions of vulnerable marine ecosystem indicator species from public databases (OBIS, NOAA and ICES), the published literature and from focused efforts from the Logachev Mounds (NE Atlantic), Tropic Seamount (NE tropical Atlantic) and Bermuda for depths below 200 m. Taxa included hexacorals, octocorals, hydroids, sponges, hydrothermal vents associated species (bivalves, decapods), crinoids and xenophyophores.

Set of terrain (static in time) and environmental (dynamic in time) variables used as candidate predictors of present-day (1951-2000) and future (2081-2100) suitable habitat of cold-water corals and deep-sea fishes in the North Atlantic

Jan, 2020

2 team members are authors

OA Citations 6 DOI 10.1594/pangaea.911117

Authors 10.1594/pangaea.911117

Chih‐Lin Wei José Manuel González‐Irusta

Carlos Dominguez‐Carrió

Telmo Morato

Abstract

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 forecast changes under severe, high emissions future (2081-2100) climate projections (RCP8.5 scenario) for the North Atlantic Ocean (from 18°N to 76°N and 36°E to 98°W). This dataset contains a set of terrain (static in time) and environmental (dynamic in time) variables were used as candidate predictors of present-day (1951-2000) distribution and to forecast future (2081-2100) changes. All predictor variables were projected with the Albers equal-area conical projection centred in the middle of the study area. The terrain variable depth was extracted from a bathymetry grid built from two data sources: the EMODnet Digital Terrain Model (EMODnet, 2018) and the General Bathymetric Chart of the Oceans (GEBCO 2014; Weatherall et al., 2015). Slope (in degrees) was derived from the final bathymetry grid using the Raster package in R (Hijmans, 2016) and the Bathymetric Position Index (BPI) was computed using the Benthic Terrain Model 3.0 tool in ArcGIS 10.1 with an inner radius of 3 and an outer radius of 25 grid cells. In order to avoid extreme values, BPI was standardized using the scale function from the Raster package. Environmental variables of present-day and future conditions, including particulate organic carbon (POC) flux at 100-m depth (epc100, mg C m-2 d-1), bottom water dissolved oxygen concentration (µmol kg-1), pH, and potential temperature (°K) were downloaded from the Earth System Grid Federation (ESGF) Peer-to-Peer (P2P) enterprise system. The epc100 was converted to export POC flux at the seafloor using the Martin curve (Martin, Knauer, Karl, & Broenkow, 1987) following the equation: epc = epc100*(water depth/export depth)-0.858, and setting the export depth to 100 m. Near seafloor aragonite (Ωar) and calcite (Ωcal) saturation were also used as candidate predictors for habitat suitability of cold-water coral species. These saturation states were computed by dividing the bottom water carbonate ion concentration (mol m-3) by the bottom water carbonate ion concentration (mol m-3) for seawater in equilibrium with pure aragonite and calcite. Yearly means of these parameters were calculated for the periods 1951-2000 (historical simulation) and 2081-2100 (RCP8.5 or business-as-usual scenario) using the average values obtained from the Geophysical Fluid Dynamics Laboratory's ESM 2G model (GFDL-ESM-2G; Dunne et al., 2012), the Institut Pierre Simon Laplace's CM6-MR model (IPSL-CM5A-MR; Dufresne et al., 2013) and Max Planck Institute's ESM-MR model (MPI-ESM-MR; Giorgetta et al., 2013) within the Coupled Models Intercomparison Project Phase 5 (CMIP5) for each grid cell of the present study area.

Blue Azores Program Expedition 2018, Station 57, Dive 15: annotation of Paragorgia johnsoni Gray, 1862

Apr, 2021

6 team members are authors

OA Citations 1 DOI 10.5281/zenodo.4727164

Authors 10.5281/zenodo.4727164

Carlos Dominguez‐Carrió

Gerald H. Taranto

Manuela Ramos Oscar Vicente Ocaña

Laurence Fauconnet Emanuel J. Gonçalves

Marina Carreiro‐Silva

Telmo Morato

Abstract

Annotation of Paragorgia johnsoni Gray, 1862 colonies from underwater video footage recorded during the Blue Azores 2018 Expedition with the ROV Luso onboard the NRP Almirante Gago Coutinho, Station 57, Dive 15 (June 23^rd, 2018). The images correspond to the octocoral garden discovered between 545 and 595 m depth on the slopes of a small ridge-like structure located on the Mid-Atlantic Ridge, in the Azores region.

Outputs of predictive distribution models of deep-sea elasmobranchs in the Azores EEZ (down to 2,000m depth) using Generalized Additive Models

Jan, 2022

3 team members are authors

OA DOI 10.1594/pangaea.940808

Authors 10.1594/pangaea.940808

González-Irusta, José Manuel

Fauconnet, Laurence Das, Diya Catarino, Diana Afonso, Pedro Viegas, Cláudia Neto

Rodrigues, Luís Menezes, Gui M Rosa, Alexandra Pinho, Mário Rui Rilhó Silva, Hélder Marques Da Giacomello, Eva

Morato, Telmo

Abstract

Description: We developed predictive distribution models of deep-sea elasmobranchs for up to 2000 m depth in the Azores EEZ and neighboring seamounts, from approximately 33°N to 43°N and 20°W to 36°W. Georeferenced presence, absence, and abundance data were obtained from scientific surveys and commercial operations reporting at least one deep-sea elasmobranch capture. A 20-year 'survey dataset' (1996-2017) was compiled from annual scientific demersal surveys using two types of bottom longlines (types LLA and LLB), and an 'observer dataset' (2004-2018) from observer programs covering commercial fisheries operations using bottom longline (similar to type LLA) and vertical handline ('gorazeira'). We used the most ecologically relevant candidate environmental predictors for explaining the spatial distribution of deep-sea elasmobranch in the Azores: depth, slope, northness, eastness, Bathymetric Position Index (BPI), nitrates, and near bottom currents. We merged existing multibeam data for the Azores EEZ with bathymetry data extracted from EMODNET (EMODnet Bathymetry Consortium 2018) to calculate depth values (down to 2000m). All variables were projected with the Albers equal-area conical projection centered in the middle of the study area and were rescaled using bilinear interpolation to a final grid cell resolution of 1.12 x1.12 km (i.e., 0.012°). Slope, northness, and eastness were computed from the depth raster using the function terrain in the R package raster. BPI was derived from the rescaled depth with an inner radius of 3 and an outer radius of 25 grid cells using the Benthic Terrain Model 3.0 tool in ArcGIS 10.1. Nitrates were extracted from Amorim et al. (2017). Near-bottom current speed (m·s-1) average values were based on a MOHID hydrodynamic model application (Viegas et al., 2018) with an original resolution of 0.054°. Besides the environmental variables, we also included three operational predictors in the analysis: year, fishing effort (number of hooks) and gear type (longline LLA and LLB, and gorazeira).

Vulnerable Marine Ecosystems, Communities, and Indicator Species: Confusing Concepts for Conservation of Seamounts

Frontiers in Marine Science

May, 2021

OA Citations 28 Rising DOI 10.3389/fmars.2021.622586

Authors 10.3389/fmars.2021.622586

Les Watling Peter J. Auster

Abstract

The concept of “vulnerable marine ecosystem” (VME) was included in United Nations (UN) General Assembly Resolution 61/105 as part of an international effort to minimize the effects of seafloor fisheries on the high seas. However, defining a VME was left to be developed by technical guidance to the UN Food and Agricultural Organization. In that venue certain categories of organisms were deemed to be indicator species, suggesting that areas with those species would be considered VMEs with subsequent management measures implemented to conserve those ecosystem attributes. We note that on seamounts VME indicator species can be distributed widely, in dense clusters or sparsely. A dense cluster, for example, of scleractinian corals or sponges, is most often referred to as a VME, but we argue that any such dense cluster is not an ecosystem, rather it is a community, likely one of many that make up the ecosystem. Other communities on the seamount that are not part of that dense cluster could include many small species (some yet to be discovered) who are also part of the ecosystem because they are part of the web of interactions and flow of materials/energy on the seamount. We also suggest that a seamount ecosystem might extend over several or many seamounts in a biogeographic area. We conclude that the term “ecosystem” in the VME concept outlined by the United Nations needs to be re-evaluated from a classical ecological perspective leading to spatial management approaches that better address ecologically relevant space and time scales.

Local-scale feedbacks influencing cold-water coral growth and subsequent reef formation

Scientific Reports

Nov, 2022

2 team members are authors

OA Citations 22 DOI 10.1038/s41598-022-24711-7

Authors 10.1038/s41598-022-24711-7

Guillem Corbera Claudio Lo Iacono Gonzalo Simarro Jordi Grinyó Stefano Ambroso Veerle A.i. Huvenne Furu Mienis

Marina Carreiro‐Silva

Inês Martins Beatriz Mano Covadonga Orejas Ann I. Larsson Sebastian Hennige Andrea Gori

Democratizing deep-sea research for biodiversity conservation

Trends in Ecology & Evolution

Oct, 2025

11 team members are authors

DOI 10.1016/j.tree.2025.09.015

Authors 10.1016/j.tree.2025.09.015

Telmo Morato

Luís Rodrigues

Marina Carreiro‐Silva

João Balsa

Inês Bruno

Inês Carneiro

Laurence Fauconnet

Guilherme Gonçalves Marc P Vilavendrell

Manuela Ramos

Gerald H. Taranto

Carlos Dominguez‐Carrió

Deep-sea ecosystems of the North Atlantic Ocean: discovery, status, function and future challenges

Deep Sea Research Part I Oceanographic Research Papers

Aug, 2025

1 team member is author

OA DOI 10.1016/j.dsr.2025.104580

Authors 10.1016/j.dsr.2025.104580

A. Louise Allcock Diva J. Amon Amelia E.h. Bridges Ana Colaço Elva Escobar‐Briones Ana Hilário Kerry L. Howell Nélia C. Mestre Frank Müller‐Karger Imants G. Priede Paul V. R. Snelgrove Kathleen Sullivan Sealey Joana R. Xavier Anna M. Addamo Teresa Amaro Geethani Bandara Narissa Bax Andreia Braga‐Henriques Angelika Brandt Saskia Brix Sergio Cambronero‐Solano Cristina Cedeño – Posso Jon Copley Erik E. Cordes Jorge Cortés Aldo Cróquer Daphné Cuvelier Jaime S. Davies Jennifer M. Durden Patricia Esquete Nicola L. Foster Inmaculada Frutos Ryan Gasbarro Andrew R. Gates Marta Gomes Lucy V.m. Goodwin Tammy Horton Thomas F. Hourigan Henk‐Jan Hoving Daniel O. B. Jones Siddhi Joshi Kelly Kingon Anne‐Nina Lörz Ana María Martins Véronique Merten Anna Meta×As Rosanna Milligan Tina N. Molodtsova

Telmo Morato Declan Morrissey Beatriz Naranjo‐Elizondo Bhavani E. Narayanaswamy Steinunn H. Ólafsdóttir Alexa Parimbelli Marian Peña Nils Piechaud Stefan Ragnarsson Sofia P. Ramalho Clara F. Rodrigues Rebecca E. Ross Hanieh Saeedi Régis Santos Patrick Schwing Tiago Da Rosa Serpa Arvind K. Shantharam Angela Stevenson Ana Belén Yánez-Suárez Tracey Sutton Jörundur Svavarsson Michelle L. Taylor Jesse Van Der Grient Nadescha Zwerschke

Assessment tool addresses implementation challenges of ecosystem-based management principles in marine spatial planning processes

Communications Earth & Environment

Jan, 2025

1 team member is author

OA Citations 15 Rising DOI 10.1038/s43247-024-01975-7

Authors 10.1038/s43247-024-01975-7

Ibon Galparsoro Natalia Montero Gotzon Mandiola Iratxe Menchaca Ángel Borja Wesley Flannery Stelios Katsanevakis Simonetta Fraschetti Erika Fabbrizzi Michael Elliott María Bas Steve Barnard G.j. Piet Sylvaine Giakoumi Maren Kruse Benedict Mcateer Robert Mzungu Runya Olga Lukyanova

Telmo Morato Annaïk Van Gerven S. Degraer Stefan Neuenfeldt Vanessa Stelzenmüller

Abstract

Abstract Ecosystem-based marine spatial planning is an approach to managing maritime activities while ensuring human well-being and biodiversity conservation as key pillars for sustainable development. Here, we use a comprehensive literature review and a co-development process with experts to build an assessment framework and tool that integrates the fundamental principles of an ecosystem approach to management and translates them into specific actions to be undertaken during planning processes. We illustrate the potential of this tool through the evaluation of two national marine spatial plans (Spain and France), in consultation with the representatives involved in their development and implementation. To ensure more coherent future planning, socio-ecological system evolution in a climate change scenario and the future marine space needs of maritime sectors should be considered, as well as improving the governance structure and knowledge of ecosystem processes. This framework provides a consistent and transparent assessment method for practitioners and competent authorities.

Drivers of trophodynamics of the open-ocean and deep-sea environments of the Azores, NE Atlantic

Progress In Oceanography

Sep, 2024

3 team members are authors

OA DOI 10.1016/j.pocean.2024.103357

Authors 10.1016/j.pocean.2024.103357

Joana Brito Ambre Soszynski Johanna J. Heymans Simone Libralato Eva Giacomello

Laurence Fauconnet Gui M. Menezes

Telmo Morato

Spatial distributions, environmental drivers and co-existence patterns of key cold-water corals in the deep sea of the Azores (NE Atlantic)

Deep Sea Research Part I Oceanographic Research Papers

Mar, 2023

6 team members are authors

OA Citations 19 Rising DOI 10.1016/j.dsr.2023.104028

Authors 10.1016/j.dsr.2023.104028

Gerald H. Taranto José Manuel González‐Irusta

Carlos Dominguez‐Carrió Christopher K. Pham Fernando Tempera

Manuela Ramos

Guilherme Gonçalves

Marina Carreiro‐Silva

Telmo Morato

Development of a sensitive detection method to survey pelagic biodiversity using eDNA and quantitative PCR: a case study of devil ray at seamounts

Marine Biology

Apr, 2017

1 team member is author

OA Citations 60 DOI 10.1007/s00227-017-3141-x

Authors 10.1007/s00227-017-3141-x

Laura Gargan

Telmo Morato Christopher K. Pham John A. Finarelli Jeanette E. L. Carlsson Jens Carlsson

A Multi Criteria Assessment Method for Identifying Vulnerable Marine Ecosystems in the North-East Atlantic

Frontiers in Marine Science

Dec, 2018

1 team member is author

OA Citations 60 Rising DOI 10.3389/fmars.2018.00460

Authors 10.3389/fmars.2018.00460

Telmo Morato Christopher K. Pham Carlos Pinto Neil Golding Jeff Ardron P. Durán-Muñoz Francis Neat

Abstract

<p>In international fisheries management, scientific advice on the presence of "vulnerable marine ecosystems" (VMEs) per United Nations resolutions, has generally used qualitative assessments based on expert judgment of the occurrence of indicator taxa such as cold-water corals and sponges. Use of expert judgment alone can be criticized for inconsistency and sometimes a lack of transparency; therefore, development of robust and repeatable numeric methods to detect the presence of VMEs would be advantageous. Here, we present a multi-criteria assessment (MCA) method to evaluate how likely a given area of seafloor represents a VME. The MCA is a taxa-dependent spatial method that accounts for both the quantity and data quality available. This was applied to a database of records of VMEs built, held and compiled by the International Council for the Exploration of the Sea (ICES). A VME index was generated which ranged from 1.51 to 4.52, with 5.0 being reserved for confirmed VME habitats. An index of confidence was also computed that ranged from 0.0 to 0.75, with 1 being reserved for those confirmed VME habitats. Overall the MCA captured the important elements of the ICES VME database and provided a simplified, spatially aggregated, and weighted estimate of how likely a given area is to contain VMEs. The associated estimate of confidence gave an indication of how uncertain that assessment was for the same given area. This methodology provides a more systematic and standardized approach for assessing the likelihood of presence of VMEs in the North-East Atlantic.</p>

Natural history collections as a basis for sound biodiversity assessments: Plexauridae (Octocorallia, Holaxonia) of the Naturalis CANCAP and Tyro Mauritania II expeditions

ZooKeys

Aug, 2019

1 team member is author

OA Citations 11 DOI 10.3897/zookeys.870.35285

Authors 10.3897/zookeys.870.35285

Íris Sampaio

Marina Carreiro‐Silva André Freiwald Gui M. Menezes Manfred Grasshoff

Abstract

Mapping biodiversity is the marathon of the 21 st Century as an answer to the present extinction crisis. A century in which science is also characterised by large scientific datasets collected through new technologies aiming to fill gaps in our knowledge of species distributions. However, most species records rely on observations that are not linked to specimens, which does not allow verification of species hypotheses by other scientists. Natural history museums form a verifiable source of biodiversity records which were made by taxonomists. Nonetheless, these museums seem to be forgotten by biologists in scientific fields other than taxonomy or systematics. Naturalis Biodiversity Center (NBC) in Leiden is care keeper of large collections of marine organisms, which were sampled in the Northeast Atlantic during the CANCAP and Tyro Mauritania II expeditions (1976–1988). Many octocorals were sampled and deposited in the NBC collection, where they became available for study and were partially identified by the senior author (M.G.) in the 1980s. Nonetheless, no checklist or taxonomic revision was published so far with the complete results. In 2016 the first author visited NBC to examine NE Atlantic Plexauridae octocorals. Plexauridae octocoral-vouchered records were listed and mapped to reveal high standard primary biodiversity records unreported so far for the NE Atlantic Ocean. Twenty-four Plexauridae species with ~ six putative new species to science were discovered and eleven new biogeographical records were made from distinct Macaronesian archipelagos. Finally, new depth range records were found for three species at sea basin level and for eight species at a regional scale.

Editorial: The Azores Marine Ecosystem: An Open Window Into North Atlantic Open Ocean and Deep-Sea Environments

Frontiers in Marine Science

Oct, 2020

1 team member is author

OA Citations 6 DOI 10.3389/fmars.2020.601798

Authors 10.3389/fmars.2020.601798

Telmo Morato Pedro Afonso Gui M. Menezes Ricardo S. Santos Mónica A. Silva

Abstract

EDITORIAL article Front. Mar. Sci., 30 October 2020 | https://doi.org/10.3389/fmars.2020.601798

Benthic O2 uptake by coral gardens at the Condor seamount (Azores)

Marine Ecology Progress Series

Feb, 2022

3 team members are authors

OA Citations 6 DOI 10.3354/meps14021

Authors 10.3354/meps14021

Lorenzo Rovelli

Marina Carreiro‐Silva Karl M. Attard Maria Rakka

Carlos Dominguez‐Carrió Meri Bilan Sabena Blackbird

Telmo Morato George A. Wolff Ronnie N. Glud

Abstract

Using the non-invasive aquatic eddy covariance technique, we provide the first oxygen (O 2 ) uptake rates from within coral gardens at the Condor seamount (Azores). To explore some of the key drivers of the benthic O 2 demand, we obtained benthic images, quantified local hydrodynamics, and estimated phototrophic biomass and deposition dynamics with a long-term moored sediment trap. The coral gardens were dominated by the octocorals Viminella flagellum and Dentomuricea aff. meteor . Daily rates of O 2 uptake within 3 targeted coral garden sites (203 to 206 m depth) ranged from 10.0 ± 0.88 to 18.8 ± 2.0 mmol m -2 d -1 (mean ± SE) and were up to 10 times higher than 2 local sandy reference sites within the seamount summit area. The overall mean O 2 uptake rate for the garden (13.4 mmol m -2 d -1 ) was twice the global mean for sedimentary habitats at comparable depths. Combined with parallel ex situ incubations, the results suggest that the octocorals might contribute just ~5% of the observed O 2 uptake rates. Deposition of particulate organic matter (POM) assessed by the sediment trap accounted for less than 10% of the O 2 demand of the coral garden, implying a substantial POM supply circumventing the deployed traps. Our results expand the database for carbon turnover rates in cold-water coral habitats by including the first estimates from these largely understudied coral gardens.

Tidal to decadal scale hydrodynamics at two contrasting cold-water coral sites in the Northeast Atlantic

Progress In Oceanography

Apr, 2023

3 team members are authors

OA Citations 8 DOI 10.1016/j.pocean.2023.103031

Authors 10.1016/j.pocean.2023.103031

Christian Mohn Jørgen L. S. Hansen

Marina Carreiro‐Silva Stuart A. Cunningham Evert De Froe

Carlos Dominguez‐Carrió Stefan F. Gary Ronnie N. Glud Cordula Göke Clare Johnson

Telmo Morato Eva Friis Møller Lorenzo Rovelli Kirstin Schulz Karline Soetaert Anna‐Selma Van Der Kaaden Dick Van Oevelen

Abstract

Cold-water corals (CWCs) thrive in areas with complex and rough topography favoring the development of highly diverse benthic communities. Several biotic and abiotic factors including organic matter supply, temperature, bottom roughness and currents are important drivers of ecosystem structure and functioning in deep-sea environments at different spatial and temporal scales. Little is known, however, how basin-scale changes in the ocean climate affect these drivers at local scales. Here, we use high-resolution implementations of the hydrodynamic model ROMS-AGRIF for estimating characteristic spatial and temporal scales of local hydrodynamics in response to variations of basin-scale currents imposed by distinct changes of the Atlantic Meridional Overturning Circulation (AMOC) in the past century. We focus on two CWC communities on the SE Rockall Bank slope and at Condor Seamount. We considered two contrasting AMOC states that were identified from the 1958–2009 hindcast of the 1/20° resolution VIKING20 North Atlantic basin-scale ocean circulation model and used as boundary conditions for the high-resolution local area models. At SE Rockall Bank, variability of near-bottom currents in both regions was largely dominated by tidal dynamics, but strongly modified by AMOC induced basin-scale variations of water mass properties and bottom currents. During strong AMOC years, waters in the main CWC depth corridor (600–1200 m) were cooler and less saline but were dominated by stronger bottom currents when compared with conditions during weak AMOC years. At Condor Seamount, bottom currents were largely unaffected by AMOC related changes close to the summit at water depths < 400 m. Kinetic energy dissipation rates derived from the 3D near-bottom velocity field appeared to positively relate with the in-situ CWC distribution. Kinetic energy dissipation is therefore proposed as a mechanistic descriptor of CWC presence as it provides a more mechanistic view of hydrodynamics driving organic matter supply to filter and suspension-feeding communities.

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

Systematic evaluation of a spatially explicit ecosystem model to inform area-based management in the deep-sea

Ocean & Coastal Management

Aug, 2023

2 team members are authors

Citations 6 DOI 10.1016/j.ocecoaman.2023.106807

Authors 10.1016/j.ocecoaman.2023.106807

Joana Brito Ambre Soszynski Christopher K. Pham Eva Giacomello Gui M. Menezes Jeroen Steenbeek David Chagaris

Telmo Morato

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

Deep Sea Research Part I Oceanographic Research Papers

Feb, 2022

3 team members are authors

Citations 20 Rising DOI 10.1016/j.dsr.2022.103707

Authors 10.1016/j.dsr.2022.103707

Diya Das José Manuel González‐Irusta

Telmo Morato

Laurence Fauconnet Diana Catarino Pedro Afonso Cláudia Viegas

Luís Rodrigues Gui M. Menezes Alexandra Rosa Mário Pinho Helder Marques Da Silva Eva Giacomello

Mechanical and toxicological effects of deep-sea mining sediment plumes on a habitat-forming cold-water octocoral

Frontiers in Marine Science

Oct, 2022

5 team members are authors

OA Citations 27 DOI 10.3389/fmars.2022.915650

Authors 10.3389/fmars.2022.915650

Marina Carreiro‐Silva

Inês Martins Virginie Riou Joana Raimundo Miguel Caetano Raúl Bettencourt Maria Rakka

Teresa Cerqueira

António Godinho

Telmo Morato Ana Colaço

Abstract

Deep-sea mining activities are expected to impact deep-sea biota through the generation of sediment plumes that disperse across vast areas of the ocean. Benthic sessile suspension-feeding fauna, such as cold-water corals, may be particularly susceptible to increased suspended sediments. Here, we exposed the cold-water octocoral, Dentomuricea aff. meteor to suspended particles generated during potential mining activities in a four weeks experimental study. Corals were exposed to three experimental treatments: (1) control conditions (no added sediments); (2) suspended polymetallic sulphide (PMS) particles; (3) suspended quartz particles. The two particle treatments were designed to distinguish between potential mechanical and toxicological effects of mining particles. PMS particles were obtained by grinding PMS inactive chimney rocks collected at the hydrothermal vent field Lucky Strike. Both particle types were delivered at a concentration of 25 mg L -1 , but achieved suspended concentrations were 2-3 mg L -1 for the PMS and 15-18 mg L -1 for the quartz particles due to the different particle density. Results of the experiment revealed a significant increase in dissolved cobalt, copper and manganese concentrations in the PMS treatment, resulting from the oxidation of sulphides in contact with seawater. Negative effects of PMS exposure included a progressive loss in tissue condition with necrosis and bioaccumulation of copper in coral tissues and skeletons, and death of all coral fragments by the end of the experiment. Physiological changes under PMS exposure, included increased respiration and ammonia excretion rates in corals after 13 days of exposure, indicating physiological stress and potential metabolic exhaustion. Changes in the cellular stress biomarkers and gene expression profiles were more pronounced in corals exposed to quartz particles, suggesting that the mechanical effect of particles although not causing measurable changes in the physiological functions of the coral, can still be detrimental to corals by eliciting cellular stress and immune responses. We hypothesize that the high mortality of corals recorded in the PMS treatment may have resulted from the combined and potentially synergistic mechanical and toxicological effects of the PMS particles. Given the dispersal potential of mining plumes and the highly sensitive nature of octocorals, marine protected areas, buffer areas or non-mining areas may be necessary to protect deep-sea coral communities.

Challenges in avoiding deep-water shark bycatch in Azorean hook-and-line fisheries

ICES Journal of Marine Science

Oct, 2022

2 team members are authors

OA Citations 12 Rising DOI 10.1093/icesjms/fsac178

Authors 10.1093/icesjms/fsac178

Laurence Fauconnet Diana Catarino Diya Das Eva Giacomello José Manuel González‐Irusta Pedro Afonso

Telmo Morato

Abstract

Abstract Deep-water sharks are highly diverse, vulnerable, and understudied as a group, despite the increasing pressures on their populations. Twenty-five species of deep-water sharks have been recorded in the Azores, an oceanic archipelago in the mid-North Atlantic, that are regularly caught as bycatch in hook-and-line fisheries. Avoiding the bycatch of deep-water sharks presents multiple challenges due to their high catchability, difficulties in correctly identifying species, and the general lack of data on these species. This review summarizes the findings of recent studies from the region, providing an up-to-date science-based framework for mitigating bycatch effects of Azorean hook-and-line fisheries. Several depth-based, area-based, and gear-based measures have been studied that demonstrate the potential to either avoid or increase the survival of deep-water shark bycatch. However, these measures may have limited efficacy for some species (e.g. highly mobile species) and thus, limited widespread applicability. Convincing fishers to avoid deep-water shark bycatch is also a challenge given the antagonistic interactions with sharks damaging the catch and fishing gear, while simultaneously a market incentive for shark liver oil remains. It highlights the need to proactively engage fishers and incentivize the mitigation of bycatch of deep-water sharks in Azorean waters.

Modelling the Dispersion of Seafloor Massive Sulphide Mining Plumes in the Mid Atlantic Ridge Around the Azores

Frontiers in Marine Science

Jul, 2022

3 team members are authors

OA Citations 21 DOI 10.3389/fmars.2022.910940

Authors 10.3389/fmars.2022.910940

Telmo Morato Manuela Juliano Christopher K. Pham

Marina Carreiro‐Silva

Inês Martins Ana Colaço

Abstract

It is increasingly recognised that deep-sea mining of seafloor massive sulphides (SMS) could become an important source of mineral resources. These operations will remove the targeted substrate and produce potentially toxic plumes from in situ seabed excavation and from the return water pumped back down to the seafloor. However, the spatial extent of the impact of deep-sea mining is still uncertain because few field experiments and models of plume dispersion have been conducted. In this study, we used three-dimensional hydrodynamic models of the Azores region together with a theoretical commercial mining operation of polymetallic SMS to simulate the potential dispersal of plumes originating from different phases of mining operations, and to assess the magnitude of potential impacts. Although the model simulations presented here were subject to many caveats, they did reveal some important patterns. The model projected marked differences among sites making generalisations about plume-dispersal patterns in mid-ocean ridges difficult. Nevertheless, the models predicted large horizontal and vertical plume-dispersals above the thresholds adopted. Persistent plumes (temporal frequency >50%, i.e., 6 months out of 12 months) were projected to disperse an average linear distance of 10 to 20 km, cover an area of 17 to 150 km2, and extend more than 800 m in the water column. In fact, the model projected that plumes may disperse beyond the licensed mining areas, reach the flanks and summits of nearby topographic features, and extend into the bathypelagic, mesopelagic, and epipelagic environments. Modelled plume-dispersal overlaps with the predicted distribution of cold-water corals and with existing fishing activities. These potential impacts would be of particular concern in regions such as the Azores, where local populations are highly dependent on the sea for their livelihoods. The findings of this study are an important initial step towards understanding the nature and magnitude of deep-sea mining impacts in space and time.

A cost‐effective video system for a rapid appraisal of deep‐sea benthic habitats: The Azor drift‐cam

Methods in Ecology and Evolution

Apr, 2021

2 team members are authors

OA Citations 37 DOI 10.1111/2041-210x.13617

Authors 10.1111/2041-210x.13617

Carlos Dominguez‐Carrió Jorge Fontes

Telmo Morato

Abstract

Abstract Deep‐sea exploration relies on cutting‐edge technology, which generally requires expensive instruments, highly specialized technicians and ship time. The increasing need to gather large‐scale data on the distribution and conservation status of deep‐sea benthic species and habitats could benefit from the availability of low‐cost imaging tools to facilitate the access to the deep sea world‐wide. Here we describe the Azor drift‐cam, a cost‐effective video platform designed to conduct rapid appraisals of deep‐sea benthic habitats. Built with off‐the‐shelf components, the Azor drift‐cam should be regarded as an effective, affordable, simple‐to‐assemble, easy‐to‐operate, resilient, operational and reliable tool to visually explore the deep sea to 1,000 m depth. Its performance was assessed during the MapGES_2019 cruise, where 135 successful dives between 100 and 800 m depth were carried out in 22 working days, providing over 100 hr of images for almost 80 km of seabed, mostly in areas that had never been explored before. The system does not aim to become a substitute for more sophisticated underwater video and photography platforms, such as ROVs, AUVs or manned submersibles. Rather, it aims to provide the means to perform quick assessments of deep‐sea benthic habitats in a simple and affordable manner. This drift‐cam system has the potential to make deep‐sea exploration more accessible, playing an important role in the Deep‐Ocean Observing Strategy and measuring some of the Essential Ocean Variables for deep‐sea monitoring and conservation strategies.

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

7 team members are authors

OA Citations 18 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

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

Fisheries Research

Oct, 2023

2 team members are authors

OA Citations 3 DOI 10.1016/j.fishres.2023.106877

Authors 10.1016/j.fishres.2023.106877

Laurence Fauconnet

Telmo Morato Diya Das Diana Catarino Jorge Fontes Eva Giacomello Pedro Afonso

Abstract

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.

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