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The ability of corals to detach their polyps (leaving behind a naked skeleton) in times of stress, allows polyps to escape from a local source of hostility (Sammarco 1982). In situ observations of this behavior (referred to as 'polyp bailout') were first documented in tropical reef-building corals. Later it was observed in some cold-water corals of Acanthogorgia (Braga-Henriques 2014), and Acanella arbuscula (Rakka et al. 2019) in aquaria.

Video and image data are regularly used in the field of benthic ecology to document biodiversity. However, their use is subject to a number of challenges, principally the identification of taxa within the images without associated physical specimens. The challenge of applying traditional taxonomic keys to the identification of fauna from images has led to the development of personal, group, or institution level reference image catalogues of operational taxonomic units (OTUs) or morphospecies. Lack of standardisation among these reference catalogues has led to problems with observer bias and the inability to combine datasets across studies. In addition, lack of a common reference standard is stifling efforts in the application of artificial intelligence to taxon identification. Using the North Atlantic deep sea as a case study, we propose a database structure to facilitate standardisation of morphospecies image catalogues between research groups and support future use in multiple frontend applications. We also propose a framework for coordination of international efforts to develop reference guides for the identification of marine species from images. The proposed structure maps to the Darwin Core standard to allow integration with existing databases. We suggest a management framework where high-level taxonomic groups are curated by a regional team, consisting of both end users and taxonomic experts. We identify a mechanism by which overall quality of data within a common reference guide could be raised over the next decade. Finally, we discuss the role of a common reference standard in advancing marine ecology and supporting sustainable use of this ecosystem.

Octocoral species are globally distributed in all oceans and may form dense communities known as vulnerable marine ecosystems. Despite their importance as deep-water habitats, the underlying genetic structure and gene-flow patterns of most deep-water populations remain largely unknown. Here, we evaluated genetic connectivity of the primnoid octocoral Narella versluysi across the continental shelf of Bay of Biscay, spanning 360 km (95 samples from submarine canyons, ranging from 709–1247 m depths). We report 12 novel microsatellite markers which were used to genotype 83 samples from 6 populations. Sixteen samples were sequenced for three mitochondrial DNA regions (Folmer region of COI with an adjacent intergenic region igr1, MT-ND2 gene, and mtMutS homolog 1 region). All sequence haplotypes and genetic clusters were found in multiple sites spanning more than 200 km. Overall, our analyses suggest that there is high gene flow between colonies of N. versluysi among all study sites. There is no significant geographic structure and no pattern of isolation by distance or depth. Connectivity is facilitated by the prevailing current which runs along the shelf break, and could be a mechanism to connect all of the sampled locations. The high connectivity over large geographic distance is a positive sign for a potentially vulnerable organism and may provide some resilience to disturbance. This information is crucial for a better understanding of how this fragile benthic fauna may respond to climatic and anthropogenic disturbances, which is a cornerstone for effective habitat management.

The first record of Antipathella subpinnata ( Ellis and Solander, 1786 ) for the Azores archipelago is presented based on bottom longline by-catch analysis and ROV seafloor surveys, extending the species western-most boundary of distribution in the NE Atlantic. The species was determined using classic taxonomy and molecular analysis targeting nuclear DNA. Although maximum spine height on Azorean colonies branchlets is slightly smaller than that reported from Mediterranean colonies (0.12 vs 0.16 mm), the analysis of partial 18S rDNA, complete ITS1, 5.8S, ITS2 and partial 28S rDNA suggests that the Azorean and Mediterranean specimens belong to the same species. Video surveys of an A. subpinnata garden detected near Pico Island are used to provide the first in situ description of the species habitat in the region and the first detailed description of a black coral garden in the NE Atlantic. With A. subpinnata being the only coral found between 150 and 196 m depths, this is the deepest black coral garden recorded in the NE Atlantic and the first one to be monospecific. The species exhibited a maximum density of 2.64 colonies/m2 and occurred across a surface area estimated at 67,333 m2, yielding a local population estimate of 50,500 colonies.

Cold-water corals are widely considered as important structural components of benthic habitats, potentially enhancing local abundance in a variety of fish and invertebrate species. Yet, current knowledge of the taxonomic diversity and distribution patterns of these vulnerable, slow-growing organisms is scarce and fragmented, limiting the effectiveness of spatial management and conservation measures. We have conducted an exhaustive compilation of records of alcyonaceans, antipatharians, scleractinians and stylasterids available through present day to assess the diversity, distribution and spatial structure of coral assemblages in the Azores exclusive economic zone (EEZ). The resulting database comprises 2501 entries concerning historical oceanographic expeditions and other published sources, as well as unpublished data from bottom longline by-catch. Our taxonomic inventory appears to be fairly complete for the explored habitats, accounting for 164 species (79 alcyonaceans, 58 scleractinians, 18 antipatharians and 9 stylasterids), nine of which were documented for the first time. The Azores EEZ harbours a mixed coral fauna with several zoogeographic origins, showing the closest affinity with the Lusitanian–Mediterranean region. Very few apparent endemics were found (14%), and only in part supported by consistent sampling. Coral diversity is particularly high between 300 and 900 m depths, in areas recognized as traditional fishing grounds or exploitable fish habitat within the 100-mile limit of the EEZ. The composition of coral assemblages shows significant geographical structure among longitudinal sections of the study area at comparable depths (100–1500 m). There is no evidence of a possible role of the Mid-Atlantic Ridge or latitudinal effects underlying this pattern, which suggests that it may instead reflect assemblage variability among features. Stronger changes in species composition were found along the bathymetric gradient. Notwithstanding the mix of partially overlapping steno- and eurybathic species that characterize the vertical distribution of corals, there is a distinct transition from shallow (100–600 m) to intermediate (600–1000 m) depths. The analysis presented here constitutes a valuable contribution for efficient conservation policies of coral-associated vulnerable marine ecosystems and their sustainable use as fishing areas.

Five colonies of black coral Leiopathes sp. were collected as bycatch from depths of 293 to 366 m from the Condor, Acor, and Voador seamounts (Azores region). The colonies had axial diameters between 4.9 and 33.1 mm and heights between 43 and 175 cm. Their ages and radial growth rates were estimated using radiocarbon dating. Results indicated that the smallest and largest colonies had similar radial growth rates of 5 to 7 µm yr �1 , whereas the other 3 colonies had grown more rapidly by a factor of 3 to 5 at ~20 to 30 µm yr �1 . Colony lifespan ranged between 265 ± 90 and 2320 ± 90 yr. Fine-scale sampling along a radial transect from the edge to the center of the 2320 yr old Leiopathes sp. revealed variable growth rates throughout the colony lifespan. Slower radial growth rates of ~4 to 5 µm yr �1 were recorded over the initial 1600 yr and the last 300 yr of its life span, and a period of more rapid growth (20 µm yr �1 ) over the intermediate 400 yr of its life. Variability in radial growth rates among colonies resulted in colony ages that were not linearly correlated to colony axis diameter or height. Our findings of great longevity and slow growth rates for Leiopathes sp. agree with other Leiopathes sp. age and growth studies, indicating that colony and population recovery from damage or removal may take centuries to millennia.

The impact of bottom trawling on cold-water corals (CWC) has been thoroughly studied and shown to be long-lasting; however the effects of bottom longlining on CWC ecosystems have received little attention. The present paper identifies the principal CWC species landed by bottom longlining in Faial (Azores) from 150 to 600 m depth. Data were obtained from a survey of 297 landings during four months coupled with 16 interviews with fishermen. A distinction was made among corals brought on deck directly entangled in the fishing gear (primary by-catch) from corals brought up associated with other larger CWC species or rocks (secondary by-catch). Forty-five (15.2%) of 297 fishing trips surveyed landed coral specimens. The survey recorded 39 different CWC taxa in the by-catch, belonging to five different orders (Scleractinia, Alcyonacea, Antipatharia, Zoanthidea and Anthoathecata). Secondary by-catch included a larger number of species but the total number of corals was in the same order of magnitude for both groups. The taxa most frequently encountered were Leiopathes spp., Errina dabneyiand Dendrophyllia sp. CWC taxa in the by-catch were mostly medium size (10–60 cm), 3-dimensional and branched colonies. Local ecological knowledge of fishermen confirmed that the corals recorded were representative of their past experience and also revealed a general agreement that there has been a decrease of CWC by-catch on traditional fishing grounds. Corals are common by-catch in bottom longline fisheries around the Azores and so conservation measures may be required.

Observations of deep-sea homolids are becoming more common, but good-resolution imagery of these crabs in the natural environment is still scarce. Sixteen new in situ observations of Paromola cuvieri from various locations within the central and eastern groups of the Azores Archipelago (Northeast Atlantic) are described here based on video footage collected by two submersible vehicles. Crabs were found on coral gardens and deep-sea sponge aggregations, which are priority habitats of conservation importance under OSPARCOM. Diverse sessile megafauna were recorded (>59 taxa), including sponges, hydroids, corals, brachiopods, crinoids and oysters. Overall, 75% of the crabs were carrying live specimens of sessile invertebrates, mainly sponges and cold-water corals. Object selection shows to be a more complex process than previously thought, in which factors such as morphology, size and weight of objects and also palatability seem to be more important in the process of object selection than their availability.

Braga-Henriques, A., Carreiro-Silva, M., Porteiro, F. M., de Matos, V., Sampaio, Í., Ocaña, O., and Ávila, S., P. 2011. The association between a deep-sea gastropod Pedicularia sicula (Caenogastropoda: Pediculariidae) and its coral host Errina dabneyi (Hydrozoa: Stylasteridae) in the Azores. – ICES Journal of Marine Science, 68: 399–407. The Azores region harbours the richest communities of stylasterid corals in the Northeast Atlantic area. Of the nine deep-water species found there, Errina dabneyi seems to be the most abundant species; it is commonly collected as bycatch from longline fishing. E. dabneyi host Pedicularia gastropods on their branches, and a detailed study of shell shape and morphometry at different growth stages, complemented by shell characterization through scanning electron microscopy, allows the individuals to be identified as Pedicularia sicula. The incidence of this species on E. dabneyi was high (69.8%), with abundances ranging between 1 and 223 individuals per colony. The pediculariids exhibited a high degree of plasticity and produced evident traces on the stylasterid skeletons at their fixation points, suggesting that they are ectoparasites and not predators of E. dabneyi. The stylasterid colonies also hosted a rich associated fauna dominated by suspension-feeders using the coral as substratum and for protection.

Carreiro-Silva, M., Braga-Henriques, A., Sampaio, I., de Matos, V., Porteiro, F. M., and Ocaña, O. 2011. Isozoanthus primnoidus, a new species of zoanthid (Cnidaria: Zoantharia) associated with the gorgonian Callogorgia verticillata (Cnidaria: Alcyonacea). – ICES Journal of Marine Science, 68: 408–415. In the Azores, Northeast Atlantic, an undescribed epizoan zoanthid is often found in association with the cold-water gorgonian Callogorgia verticillata at 110–800 m depth. This zoanthid was identified as a new species, Isozoanthus primnoidus sp. nov., based on morphological and anatomical characters of the polyps and type of cnidae. The distinguishing features of I. primnoidus are coenenchyme, column, and oral disc light brown, with short, translucent tentacles. Contracted polyps have column diameter up to 3 mm and height up to 2 mm. Ectoderm and outer mesogloea are densely encrusted with mineral particles and gorgonian sclerites. Capitulum bears a maximum of 14 distinctive ridges. Isozoanthus primnoidus was associated with 17% of C. verticillata colonies studied, and covered 14 ± 5% of the gorgonian colony. There was strong evidence of a parasitic relationship whereby I. primoidus progressively eliminates gorgonian tissue and uses the gorgonian axis for structure and support, and sclerites for protection.

Heteropathes opreski, a new antipatharian species from the northern border of the Oceanographer Fracture Zone is here described and illustrated. An emended diagnosis of the genus and a dichotomous key containing the four Heteropathes species are presented. This species is unique in that it forms smaller colonies compared to the other species in the genus, with some of the lateral pinnules presenting a small ramified subpinnule. Additionally, the polypar spines found on the lateral pinnules are the highest so far recorded in the genus. This record greatly expands the known distribution of this genus, as it was not previously reported to occur in the Northeastern Atlantic.

Bottom trawl fishing threatens deep-sea ecosystems, modifying the seafloor morphology and its physical properties, with dramatic consequences on benthic communities. Therefore, the future of deep-sea fishing relies on alternative techniques that maintain the health of deep-sea ecosystems and tolerate appropriate human uses of the marine environment. In this study, we demonstrate that deep-sea bottom longline fishing has little impact on vulnerable marine ecosystems, reducing bycatch of cold-water corals and limiting additional damage to benthic communities. We found that slow-growing vulnerable species are still common in areas subject to more than 20 years of longlining activity and estimate that one deep-sea bottom trawl will have a similar impact to 296–1,719 longlines, depending on the morphological complexity of the impacted species. Given the pronounced differences in the magnitude of disturbances coupled with its selectivity and low fuel consumption, we suggest that regulated deep-sea longlining can be an alternative to deep-sea bottom trawling.

Publisher Summary Seamounts are among the most common topographic features in the world ocean. Depending on their particular morphological traits, they can also be referred to as banks, knolls, guyots, mounds, or hills. Condor seamount is a linear volcano located in the Azores (northeast Atlantic), 35 km in length, 2–6 km wide, and of varied seafloor morphology. A scientific observatory devoted to research on seamount ecosystem structure and functioning has been established on Condor, secured by a temporary fishing closure. Multiple projects have contributed to this observatory by targeting the seamount with snapshots and long-term deployments of moored, satellite-based, and shipborne technologies. This chapter presents a brief characterization of the seamount's seafloor environment by focusing on the multibeam bathymetry data and a series of video, oceanographic, and fishery surveys. A classification based upon the bathymetric position index is presented to characterize the landscape composition of the seamount. Habitats of conservation importance, such as coral gardens and deep-sea sponge aggregations, are documented. A qualitative zonation of the benthic assemblages based on the video surveys is presented along with dominant fish and crustacean catch data for comparable depth strata. Understanding how deep-sea habitat-building species like corals and sponges distribute at fine scales over the complex topography of individual seamounts is therefore critical information to design usage zonation schemes.

A reef formed by corals of the azooxanthellate scleractinian genus EguchipsammiaCairns, 1994 (Dendrophylliidae), identified following the morphological descriptions by Zibrowius (1980) and Cairns (2000), was discovered in July 2013 off the Faial-Pico Channel (Azores, Northeast Atlantic). This is the first record of such an extensive living Eguchipsammia framework and the first major discovery by the RebikoffNiggeler Foundation with its recently-inaugurated manned submersible Lula 1000. The recently located reef was found at 280–300 m depth, on the very top of a partially collapsed and rejuvenated volcanic cone (Fig. 1a). This dense framework covers an estimated 1,000 m, with the living bright yellow polyps standing out from the dead skeletons (Fig. 1b–d). The underlying substrate is partially visible, suggesting that the reef is less than 1 m thick. The distribution range of the genus Eguchipsammia in the Atlantic Ocean previously included multiple localities in the Gulf of Mexico and Caribbean, at depths between 9 and 300 m, and southwestern Europe, from the Coral Patch Seamount to the Celtic Sea at depths ranging between 330 to 960 m (Cairns 2000; Wienberg et al. 2013). The present record attests the presence of the genus in the central North Atlantic, filling the gap within its amphi-Atlantic distribution

Four species of ring sea anemones (Cnidaria, Anthozoa, Actiniaria) have been recorded from the Indo-Pacific region (Hiles, 1899; Ocana et al., 2004). They occur in parasitic association with gorgonian and pennatulacean species and surround these cnidarian hosts with a solid piece of pedal disc tissue. Until now, these species have been placed in the Family Actinostolidae (Carlgren, 1949). According to Ocana et al. (2004) they may constitute a new family of sea anemones. Unfortunately, most of the material of ring sea anemones was stored in the octocoral collections and consequently fixed in ethanol. Ethanol is not a good chemical to fix material for histological purposes and also makes it very difficult to observe the capsules of the cnidome. We wait till new material can be collected in order to study the species from the point of view of taxonomy. The present paper reports a new species of ring sea anemone (Peronanthus sp.5) from the Atlantic (Azores Islands) that was found attached to the gorgonian Keratoisis grayi Wright, 1869 (Octocorallia, Gorgonacea, Isididae). Unfortunately, the two specimens of Peronanthus sp.5 studied were fixed in alcohol together with their hosts and this makes it very difficult to study this material with taxonomical purposes. New material will be necessary to advance with the study of this interesting species. Two fragments of Keratoisis grayi Wright, 1869 (Fig. 1) harbouring the ring sea anemones were collected in the Sedlo Seamount (40o20.8680’N; 26o50.2600’W) near the Azores, at depths between 1069 and 1156 m. We only found two specimens of Peronanthus sp.5 associated with two small pieces of the material of K. grayi. The material was sampled during the FISHOR expedition carried out in January 2002 onboard the FV Pakura, using a bottom trawl. Seawater temperature ranged between 5o and 6oC. The specimens were deep frozen, later preserved in 70% ethanol and stored in the biological reference collection of the Department of Oceanography and Fisheries (DOP), Azores (Dop181-ANT). Four similar species have been previously recorded from the Indo-Pacific (see Ocana et al., 2004). Tentacles and pedal ring of the fixed material are brown. The expanded specimen is 0.5 cm long and 0.3 cm wide, while the pedal ring of the retracted specimen measures 0.3 cm long. The species Peronanthus sp.2 is morphologically the most similar species. Peronanthus sp.1 and Peronanthus sp.5 were both growing on species of the genus Keratoisis Wright, 1869. This genus presents large polyps and, as a consequence of this characteristic, the anemone is placed between the gorgonian calyces (see Ocana et al., 2004). As in Peronanthus sp.1 and sp.2, Peronanthus sp.5 displaces the gorgonian polyps and their coenenchyme (see Fig. 2-3). Some large sclerites and Notas / Notes

Heteropathes opreski, a new antipatharian species from the northern border of the Oceanographer Fracture Zone is here described and illustrated. An emended diagnosis of the genus and a dichotomous key containing the four Heteropathes species are presented. This species is unique in that it forms smaller colonies compared to the other species in the genus, with some of the lateral pinnules presenting a small ramified subpinnule. Additionally, the polypar spines found on the lateral pinnules are the highest so far recorded in the genus. This record greatly expands the known distribution of this genus, as it was not previously reported to occur in the Northeastern Atlantic.