Les amphipodes tubicoles des épaves du plateau continental belge

Shipwrecks of the Belgian Continental Shelf harbors rich and diversified epibenthic communities. In terms of density, tube builder and dweller amphipods are important component of the communities of these hard structures lying in a sea of soft sediments. Four sites at varying distance from the coast were investigated through SCUBA techniques. Three species, Jassa herdmani (Walker, 1893), Monocorophium sextonae Crawford, 1937 and Monocorophium acherusicum Costa, 1851, were identified with contrasting occurrence and densities on the different sites. J. herdmani is present on all the investigated sites with maximal density of 615.200 ind/m2. M. sextonae is found on intermediate and offshore sites at maximal density of 29.200 ind/m2. M. acherusicum has maximal density of 4.990 ind/m2 but is only found on intermediate and close to the coast sites. The occurrence of M. acherusicum close to the coast is probably related to its affinity to water with a reduced salinity

Belgian shipwreck: hotspots for marine biodiversity BEWREMABI: final report

The main aim of the project is to document the fauna found on five shipwrecks in the Belgian part of the North Sea (map). While we have a fairly good understanding of the fauna of soft bottoms of our part of the North Sea, the fauna of these artificial hard substrates is largely unknown. Study of these habitats will allow us to understand species distribution patterns, and allow us to predict which species to expect on other artificial hard substrates, such as sokkels of wind mills. It is a two year research project carried out in the framework of the SPSD-II research action of the Belgian Federal Science Policy Office

Belgian shipwrecks: hotspots for marine biodiversity

Hard bottom substrates at sea allow the development of communities that are often rich in terms of species diversity. Non-biogenic structures such as shipwrecks are an integral part of these substrates, even if they have an anthropogenic origin and the species assemblages they harbor could be for that reason qualified as 'exotic'. There are 200 recent shipwrecks on the Belgian Continental Shelf (BCS), which represent a large fraction of the hard substrate available locally; their presence has an additional interest if we know that the major part of the English Channel and Southern Bight of the North Sea consists almost exclusively of soft sediments. Five shipwrecks on the BCS will be studied in order to assess the meio- and macrofaunal diversity using direct observations and scuba sampling techniques. The soft sediments close to shipwrecks will also be studied to serve as model for areas relatively undisturbed by fisheries (untrawled). Added to this, the influence of shipwrecks on local hydrodynamics and sediment transport will favor the colonization by fragile epibenthic species and as a consequence increase habitat complexity. For each site, standard abiotic parameters and current vectors will be measured and modeled. The information will be centralized in a database and disseminated through a web site devoted to the biodiversity of the BCS. The results will be relevant to the management of the BCS; the anthropogenic hard substrates of shipwrecks can serve as a model for what will happen with the installation of offshore windmills. A brochure will increase public awareness of the importance of marine diversity, and increase public support for marine protected areas

Connectivity of larval stages of sedentary marine communities between hard substrates and offshore structures in the North Sea

Man-made structures including rigs, pipelines, cables, renewable energy devices, and ship wrecks, offer hard substrate in the largely soft-sediment environment of the North Sea. These structures become colonised by sedentary organisms and non-migratory reef fish, and form local ecosystems that attract larger predators including seals, birds, and fish. It is possible that these structures form a system of interconnected reef environments through the planktonic dispersal of the pelagic stages of organisms by ocean currents. Changes to the overall arrangement of hard substrate areas through removal or addition of individual man-made structures will affect the interconnectivity and could impact on the ecosystem. Here, we assessed the connectivity of sectors with oil and gas structures, wind farms, wrecks, and natural hard substrate, using a model that simulates the drift of planktonic stages of seven organisms with sedentary adult stages associated with hard substrate, applied to the period 2001–2010. Connectivity was assessed using a classification system designed to address the function of sectors in the network. Results showed a relatively stable overall spatial distribution of sector function but with distinct variations between species and years. The results are discussed in the context of decommissioning of oil and gas infrastructure in the North Sea

An Assessment of Mobile Predator Populations along Shallow and Mesophotic Depth Gradients in the Hawaiian Archipelago.

Large-bodied coral reef roving predators (sharks, jacks, snappers) are largely considered to be depleted around human population centers. In the Hawaiian Archipelago, supporting evidence is primarily derived from underwater visual censuses in shallow waters (=30?m). However, while many roving predators are present or potentially more abundant in deeper strata (30-100?m+), distributional information remains sparse. To partially fill that knowledge gap, we conducted surveys in the remote Northwestern Hawaiian Islands (NWHI) and populated Main Hawaiian Islands (MHI) from 2012-2014 using baited remote underwater stereo-video. Surveys between 0-100?m found considerable roving predator community dissimilarities between regions, marked conspicuous changes in species abundances with increasing depth, and largely corroborated patterns documented during shallow water underwater visual censuses, with up to an order of magnitude more jacks and five times more sharks sampled in the NWHI compared to the MHI. Additionally, several species were significantly more abundant and larger in mesophotic versus shallow depths, which remains particularly suggestive of deep-water refugia effects in the MHI. Stereo-video extends the depth range of current roving predator surveys in a more robust manner than was previously available, and appears to be well-suited for large-scale roving predator work in the Hawaiian Archipelago

The use of taxonomic relationships among species in applied ecological research: Baseline, steps forward and future challenges

Taxonomy is more than a mere exercise of nomenclature and classification of biological diversity: it profiles the identity of species by investigating their biological and ecological traits. Taxonomy is intimately related to ecology which, in turn, cannot be a mere exercise in describing ecological patterns, but instead requires deep knowledge of species’ biological structures, roles, interactions and functions. Thus, the study of taxonomic and phylogenetic relatedness of species is of paramount importance in ecological research, enabling insights into potential evolutionary patterns and processes, allowing a more comprehensive view of biodiversity, and providing opportunities to improve the assessment and monitoring of ecological changes in time and space. The work of K. Robert (‘Bob’) Clarke forged new pathways in this direction, providing new ideas and statistical tools to include and exploit taxonomic relationships in applied marine ecological studies and beyond, also inspiring the next generation of ecologists. In this short review, we synthesise the application and development of these tools and concepts in marine biodiversity research over the last three decades and suggest future pathways in this evolving field

Epifaunal inventory of two shipwrecks from the Belgian Continental Shelf

Shipwrecks are almost the only subtidal substrata available for epifaunal colonization along the Belgian coastal waters and have never been scientifically prospected up to now. Two shipwrecks have been investigated during the summers of 2001 and 2002. De-visu observations and examination of 14 scraped surfaces of 0.0625 m2 allowed the identification of a total of 121 macrofauna species. Species richness cumulative curves provide an estimated number of 150–280 species. Both shipwrecks are dominated by Cnidarians. The tube-dwelling amphipod Jassa herdmani was also particularly abundant. Striking differences were observed between shipwrecks. Different faunal assemblages were observed on vertical and horizontal surfaces. Species richness could not been correlated with diversity indices. Samples with high species diversity were observed when the Hydrozoan Tubularia indivisa was dominant. On the contrary, when the Anthozoan Metridium senile was dominant, samples showed a very low species richness. Finally, the Poriferan Dysidea fragilis has to be considered as a new species for the Belgian fauna

Temporal variation of <i>Tubularia indivisa</i> (Cnidaria, Tubulariidae) and associated epizoites on artificial habitat communities in the North Sea

We have analyzed the composition, diversity, density and biomass of a temporal series of samples taken in a Tubularia indivisa community, which dominates a shipwreck in the North Sea waters (N 51°23',730-E 02°29',790, 17 nautical miles from the coast, 30 m depth). This shipwreck has structures emerging up to 8 m above the seabed. Water temperature ranged from 4.2°C in March to 20.3°C in August. Salinity showed few variations around 33.9 psu. Bottom tidal currents followed a semi-diurnal cycle and were preferentially NE oriented with 84% of them in the range 0.25-0.75 m s-1. The mean value for total suspended matter was 6.2 mg l-1 with large variations on a monthly scale. The species richness of samples varied from 15 in October to 42 in August with a mean value of 33 species. Diversity indices were higher during autumn and winter because of the strong dominance of a few crustacean species during the warmer months. The total density of individuals ranged from 6,500 ind m-2 in October to 445,800 ind m-2 in July, most of these individuals belonging to the amphipod species Jassa herdmani. The biomass of the T. indivisa community varied from 9 g AFDW m-2 in October to 1,106 g AFDW m-2 in July, with T. indivisa itself constituting between 59 and 82% of the total biomass. The biomass of T. indivisa was positively correlated with species richness and with the density of 23% of the species identified on this community, suggesting that T. indivisa plays an important structural role in this habitat. This was further confirmed by the number of species associated with T. indivisa which was generally superior to 55% of the sorted species. Multivariate analysis indicated strong differences between spring/summer-autumn/winter assemblages mostly but not solely due to the abundance patterns of species. These findings support the conclusion that shipwrecks in Belgian waters allow the development of assemblages dominated by a high biomass of T. indivisa which in turn provides shelter for high densities and biomass of epizoites. These assemblages will further show large monthly variations in densities and composition due to large variation in T. indivisa biomass under an apparent repetitive annual cycle