Do cold water corals provide an essential habitat for Helicolenus dactylopterus (Delaroche, 1809) in the Northwest Africa?

Cold water corals (CWC) provide habitats for many organisms including demersal fish. Bottom trawl observations have indicated a co-occurrence of the fish Helicolenus dactylopterus with CWC reefs, but a detailed understanding of this relation is lacking. To better understand the nature of this relation we have analyzed 85 video-lines from ROV dives conducted at 25-1700 m depth off Morocco, Mauritania, and Senegal in 2020 and 2021. We annotated abundance, size, and behavior of the 552 specimens observed (32% juveniles and 68% adults), of these 82% occurred in CWC habitats at 400-600 m depth. Both juveniles and adults were observed standing on the seafloor. Our observations are discussed considering available knowledge on feeding ecology and life cycle of H. dactylopterus. Our findings show that CWC provides an essential habitat for this species at least during parts of its lifecycle, however, more behavioral studies are needed for an in-depth understanding of this association.

A new species of Crinoniscus Pérez, 1900 (Crustacea: Isopoda: Crinoniscidae) parasitising the pedunculate barnacle Heteralepas newmani Buhl-Mortensen & Mifsud (Cirripedia: Heteralepadidae) with notes on its ecology and a review of the genus.

The new species Crinoniscus stroembergi n. sp. belonging to the parasitic isopod family Crinoniscidae Bonnier, 1900, is described from a pedunculate barnacle host collected in the Mediterranean Sea. This is the first species of Crinoniscus Pérez, 1900 described from a host in the genus Heteralepas Pilsbry. The male cryptoniscus larva is distinguished from congeneric species by having a dorsoventrally flattened body with the posterolateral margins of the cephalon scarcely extending beyond the anterior margin of pereomere 1 (in contrast to C. cephalatus Hosie, 2008 with extended margins); articles 1 and 2 of the antennule being subequal in width and the anterodistal angle of antennule article being low and rounded; propodus of pereopods 6 and 7 having a sinuous dorsal margin that is distally narrowing and the posterior margin of the pleotelson being short and rounded. The mature females of species in Crinoniscus are of two basic forms: those with ventrolateral lobes on the pereomeres (C. alepadis (Gruvel, 1901) n. comb., and C. politosummus Hosie, 2008) and those lacking such lobes (C. cephalatus and C. stroembergi n. sp.). The mature females of C. stroembergi n. sp. can be distinguished from other species of Crininiscus based on their lacking lobes on the anterior end. The material examined includes the male and three female developmental stages of the parasite in the host, Heteralepas newmani Buhl-Mortensen & Mifsud. The mouthparts of the immature female are described and the feeding biology and effects on the host are discussed along with a review of feeding modes in species of the Cryptoniscoidea. Leponiscus alepadis is transferred to Crinoniscus; the latter genus now contains five species. A modified diagnosis of Crinoniscus is provided.

Does grab size influence sampled macrofauna composition? A test conducted on deep-sea communities in the northeast Atlantic.

In deep-sea surveys, heavy gears are often preferred to effectively collect macro benthos while smaller samplers are sufficient in coastal and shallow areas. However, there are few comparative studies of the samples retained and results gained from different-sized grabs. To study the differences in sampling properties between a small (sampling area of 0.1 m2) and a large (0.25 m2) van Veen grab, 1 m2 of seafloor was sampled with each of the grab sizes at four test sites in the Barents- and Norwegian Sea; one inside a fjord and three offshore, across a depth range of 287-963 m. Overall, the small and large grab collected a comparable number of species and individuals: 248 and 233 species, and 6074 and 6143 individuals, respectively. The large grab retrieved the most species at the deepest location while the small grab collected more species at the other test sites. Based on internationally recommended 0.5 m2 sampling units, a variation in the total species richness per test site of 7-13% was found while the diversity indices (ES100 and H') varied by less than 10%. Independent of grab size, a cluster and nMDS analysis showed four clearly separated sample-groups that correspond to the four test stations although the multivariate dispersion was consistently higher for the small grab. A SIMPROF test showed no grab size-dependent differences. ANOSIM and PERMANOVA tests showed differences between grab sizes for the deepest station, where a similar difference occurred also between samples of the same grab size. This station displayed the least faunal heterogeneity, indicating that faunal patchiness may influence any grab-size differences. The results indicate that the two van Veen grabs tested deliver comparable quantitative faunal compositions. For the small grab, however, numerous samples were rejected due to poor performance, resulting in increased sampling time, ship costs and a suggested biased sampling towards less heterogeneous sediments at the fjord site.

Bottom trawl fishing footprints on the world's continental shelves.

Bottom trawlers land around 19 million tons of fish and invertebrates annually, almost one-quarter of wild marine landings. The extent of bottom trawling footprint (seabed area trawled at least once in a specified region and time period) is often contested but poorly described. We quantify footprints using high-resolution satellite vessel monitoring system (VMS) and logbook data on 24 continental shelves and slopes to 1,000-m depth over at least 2 years. Trawling footprint varied markedly among regions: from <10% of seabed area in Australian and New Zealand waters, the Aleutian Islands, East Bering Sea, South Chile, and Gulf of Alaska to >50% in some European seas. Overall, 14% of the 7.8 million-km2 study area was trawled, and 86% was not trawled. Trawling activity was aggregated; the most intensively trawled areas accounting for 90% of activity comprised 77% of footprint on average. Regional swept area ratio (SAR; ratio of total swept area trawled annually to total area of region, a metric of trawling intensity) and footprint area were related, providing an approach to estimate regional trawling footprints when high-resolution spatial data are unavailable. If SAR was ≤0.1, as in 8 of 24 regions, there was >95% probability that >90% of seabed was not trawled. If SAR was 7.9, equal to the highest SAR recorded, there was >95% probability that >70% of seabed was trawled. Footprints were smaller and SAR was ≤0.25 in regions where fishing rates consistently met international sustainability benchmarks for fish stocks, implying collateral environmental benefits from sustainable fishing.

Amphipod family distributions around Iceland.

Amphipod crustaceans were collected at all 55 stations sampled with an epibenthic sledge during two IceAGE expeditions (Icelandic marine Animals: Genetics and Ecology) in 2011 and 2013. In total, 34 amphipod families and three superfamilies were recorded in the samples. Distribution maps are presented for each taxon along with a summary of the regional taxonomy for the group. Statistical analyses based on presence/absence data revealed a pattern of family distributions that correlated with sampling depth. Clustering according to the geographic location of the stations (northernmost North Atlantic Sea and Arctic Ocean) can also be observed. IceAGE data for the Amphilochidae and Oedicerotidae were analysed on species level; in case of the Amphilochidae they were compared to the findings from a previous Icelandic benthic survey, BIOICE (Benthic Invertebrates of Icelandic waters), which also identified a high abundance of amphipod fauna.

Marine litter in the Nordic Seas: Distribution composition and abundance.

Litter has been found in all marine environments and is accumulating in seabirds and mammals in the Nordic Seas. These ecosystems are under pressure from climatic change and fisheries while the human population is small. The marine landscapes in the area range from shallow fishing banks to deep-sea canyons. We present density, distribution and composition of litter from the first large-scale mapping of sea bed litter in arctic and subarctic waters. Litter was registered from 1778 video transects, of which 27% contained litter. The background density of litter in the Barents Sea and Norwegian Sea is 202 and 279 items/km2 respectively, and highest densities were found close to coast and in canyons. Most of the litter originated from the fishing industry and plastic was the second most common litter. Background levels were comparable to European records and areas with most littering had higher densities than in Europe.

The use of benthic indicators in Europe: from the Water Framework Directive to the Marine Strategy Framework Directive.

The Water Framework Directive (WFD) and the Marine Strategy Framework Directive (MSFD) are the European umbrella regulations for water systems. It is a challenge for the scientific community to translate the principles of these directives into realistic and accurate approaches. The aim of this paper, conducted by the Benthos Ecology Working Group of ICES, is to describe how the principles have been translated, which were the challenges and best way forward. We have tackled the following principles: the ecosystem-based approach, the development of benthic indicators, the definition of 'pristine' or sustainable conditions, the detection of pressures and the development of monitoring programs. We concluded that testing and integrating the different approaches was facilitated during the WFD process, which led to further insights and improvements, which the MSFD can rely upon. Expert involvement in the entire implementation process proved to be of vital importance.