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Intertidal polychaete aggregations may be protected in the European Union under the Habitats Directive framework as reef habitats. Remote reef mapping remains challenging due to severe and dynamic conditions, as well as cover and spatial resolution requirements. This study (1) evaluated kite aerial photography and low-altitude digital photogrammetry to map and monitor intertidal aggregations of a sessile tube-building polychaete, Lanice conchilega (L. conchilega), and (2) developed a protocol for its remote identification. Monthly campaigns yielded 12 aerial image sets which were processed using structure-from-motion into high-precision digital terrain models and orthophoto mosaics. Maximum likelihood classification distinguished L. conchilega from bare sediment with an accuracy of 70% ± 23.2%. Aggregations were delineated by extracting elements of positive elevation from local difference models. The method has proven useful to detect high-value aggregations, distinguishing these consistently. Nevertheless, systematic biases were present during delineation, and further characterisation of reference aggregations may improve detection.

As the Ocean continues to be a focus for development in Europe through the European Commission’s Blue Growth initiative and through the Blue Economy, the importance of the marine and maritime industries will continue to grow. The knowledge, experience and innovative ideas needed to enable this development will be largely supplied by future marine professionals, or the marine graduates of today. Subsequently, the envisioned growth will require a skilled workforce of highly training and multi-skilled graduates from a wide variety of marine and maritime professional backgrounds. In addition, less established areas such as marine biotechnology and marine renewable energy may require new knowledge, skills, collaboration and innovation.It is therefore timely to examine the current marine graduate education and training system, identifying issues, challenges and opportunities. This Future Science Brief explores this complex landscape, to better understand the current status of education systems, and research and training funding mechanisms. It then looks at options to improve current capabilities across Europe at both Masters and Doctoral levels, and outlines a vision for the future of marine and maritime education and training in Europe. Case studies are presented to illustrate good practice, alongside interviews with recent marine graduates who have themselves benefitted from innovative training opportunities. The Future Science Brief then identifies ways in which to improve and broaden the skills and capabilities of the next generation of graduates. This includes enabling exposure to industry, encouraging interdisciplinary research and promoting the importance of transferable skills to graduates and industry alike. It closes by presenting 6 key recommendations for the future development of marine graduate training in Europe, and calls for collaboration between key actors from the marine education community, the marine and maritime industries, and research funding to come together to jointly develop an education and training system which will benefit all.

The effect of short-term hypoxia (6 days) on the feeding activity of abundant nematode genera was investigated by means of a tracer experiment. Nematodes were sampled from the Paulina intertidal flat in the Westerschelde estuary (south-west Netherlands) and incubated with 13C pre-labelled diatoms at the sediment-water interface in oxic and hypoxic treatments. In general, specific uptake and uptake of carbon per unit of nematode carbon were low in all studied genera, which indicated that the added diatoms represented a limited food source for the investigated nematode genera. Results from such a low uptake are difficult to interpret; however, there was no significant decrease in feeding activity of all dominant nematodes in the hypoxic treatments. The low carbon uptake might be related to low access of nematodes and their low feeding preference to the added diatoms in the experimental cores.

A combination of stomach content analyses and dual stable isotope analyses was used to reveal the trophic ecology of Atlantic seabob shrimp Xiphopenaeus kroyeri off the coast of Suriname. This coastal penaeid shrimp species has a rather omnivorous diet, feeding opportunistically on both animal prey and primary food sources. The species is a predator of hyperbenthic crustaceans, including copepods, amphipods and the luciferid shrimp Lucifer faxoni, which are mainly preyed upon during daytime, when these prey typically reside near the seabed. Benthic microalgae (BM) from intertidal mudflats and offshore sedimentary organic matter (SOM) were important primary food sources. Due to their depleted 13C values, coastal sedimentary and suspended organic matter, and carbon from riverine and mangrove-derived detritus were not incorporated by X. kroyeri. An ontogenetic diet shift was observed from postlavae to juveniles and adults. Adult X. kroyeri were located higher in the food chain, mainly preying on larger benthic organisms. Intertidal BM were an important food source for all life stages of X. kroyeri, contributing up to 64% to the overall diet based on a Bayesian mixing model. Because X. kroyeri is the main epibenthic organism found at high densities in nearshore waters up to 30 m depth, the species plays a crucial role in transferring energy from low trophic level prey and primary food sources up to higher levels in the food chain. Our results indicate that primary production on intertidal mudflats, through BM, forms an important energy source for the subtidal turbid-water food web in muddy tropical coasts. Conservation of intertidal areas and their associated mangrove systems will therefore likely benefit coastal shrimp production and fisheries in tropical ecosystems.

With the wide scale construction of offshore wind farms (OWFs) throughout the entire North Sea, large areas are permanently being closed to beam trawl fisheries. Beam trawling has affected macrobenthic assemblages for centuries, especially the fragile and long-lived species. Due to the prohibition of bean trawling in many OWFs, opportunities are being provided to investigate the potential recovery of vulnerable species and the creation of de-facto Marine Protected Areas (MPAs). The soft-substrate macrobenthic community was investigated from 2008 to 2012, before and after the construction of an OWF in the Belgian part of the North Sea, situated on the Bligh Bank. The fishery enclosed area (±21 km2) within the OWF (No Fishery area) was compared with a surrounding control area (±30 km2) where regular fishing activities were registered through vessel monitoring system (VMS) data throughout the period 2010–2011. Three years after the exclusion of beam trawl fisheries, subtle changes within the macrobenthic community were observed in the No Fishery area. The benthic mysid shrimp Gastrosaccus spinifer (30 ± 15 ind m−2), tube-building polychaetes Terebellidae sp. (196 ± 151 ind m−2) and the echinoderm Echinocyamus pusillus (73 ± 71 ind m−2), sensitive to trawling activities, showed increased abundances within the No Fishery area. With an expansion of the wind farm concession area to 238 km2 in the future, the likely increase of dense Terebellidae patches (e.g., Lanice conchilega reefs) within the No Fishery area could create an ecological important large-scale refugium for higher trophic levels. This study creates a baseline for the evaluation of long-term changes due to the fishing impacts and effects related to the presence of OWFs and highlights the importance of executing long-term monitoring programs in combination with targeted research.

Biogenic reefs constructed by the tube-building ecosystem engineer Lanice conchilega (Terrebilidae, Polychaeta) have profound structuring impacts on the benthic environment in that they alter the biogeochemical and physical properties of the sediment. This study provides new insights into the functioning and effects on food webs of L. conchilega reefs in intertidal sediments using linear inverse models to quantify the carbon flows in the food webs in the presence and absence of the tubeworm. The inverse food web models were based on an empirical dataset from 2 study sites, which provided biomass and stable isotope data, and information on general physiological constraints from the literature. Results of the model showed that the carbon input into reef food webs (mean ± SE; 191 ± 50 mmol C m -2 d -1 ) is ca. 40 times higher compared to bare sand areas (5 ± 2 mmol C m -2 d -1 ) and is mainly derived from organic matter (OM) in the water column. Most of the OM input towards these reefs is consumed by suspension-feeding macrofauna, particularly L. conchilega ; however, the worm is not an important source of carbon for other macrofaunal organisms. The ratio of OM input to primary production indicates that the OM needs to be produced in an area at least 15 times larger than the reef area, demonstrating significant OM ‘focussing’ within the reef food web. The reef structures created by L. conchilega act as a trap for OM, resulting in an overall higher macrofaunal biomass and much more diverse food webs than in the absence of the tubeworm.

Ecosystem engineers can considerably affect the community composition, abundance and species richness of their environment. This study investigates the existence of positive or negative feedbacks of species that compose the community in intertidal biogenic reefs constructed by the ecosystem engineer Lanice conchilega. This tubeworm creates attractive nursery and feeding grounds for the predatory brown shrimp Crangon crangon, while at the same time is preyed upon by C. crangon. The effect of the predation pressure exerted by C. crangon on the bioirrigation and feeding activity of the tubeworm is up until now unknown and it is hypothesised that these activities are affected by the high densities of C. crangon in the reefs. A mesocosm experiment was set up to investigate the effects of predation pressure on the bioirrigation and feeding activity of L. conchilega in the i) absence; ii) restricted presence; and iii) unrestricted presence of C. crangon. Bioirrigation was quantified by the decrease of an artificially introduced bromide (Br−) tracer, while feeding activity was measured from the incorporation of 13C via stable isotope analysis. The bioirrigation rate of the L. conchilega reef equalled about 30 L·m− 2·d− 1 and was not affected by the presence of the predator. The food uptake of the tubeworm was however about three times lower in the unrestricted presence of C. crangon, presumably due to the retraction of the worm's body and tentacles in its tube induced by physical contact with the predator. Notwithstanding the impacted food uptake of L. conchilega, the tubeworm maintains its functional role in the presence of predators in soft-bottom intertidal areas.

Underwater sound generated by pile driving during construction of offshore wind farms is a major concern in many countries. This paper reports on the acoustic stress responses in young European sea bass Dicentrarchus labrax (68 and 115 days old), based on four in situ experiments as close as 45 m from a pile driving activity. As a primary stress response, whole-body cortisol seemed to be too sensitive to 'handling' bias. On the other hand, measured secondary stress responses to pile driving showed significant reductions in oxygen consumption rate and low whole-body lactate concentrations. Furthermore, repeated exposure to impulsive sound significantly affected both primary and secondary stress responses. Under laboratory conditions, no tertiary stress responses (no changes in specific growth rate or Fulton's condition factor) were noted in young sea bass 30 days after the treatment. Still, the demonstrated acute stress responses and potentially repeated exposure to impulsive sound in the field will inevitably lead to less fit fish in the wild. (C) 2015 Elsevier Ltd. All rights reserved.

The spatio-temporal distribution and population dynamics of the non-indigenous ctenophore Mnemiopsis leidyi A. Agassiz 1865 were investigated through monthly and quarterly surveys in 2011–2012 at several locations in the Belgian part of the North Sea, the main coastal ports and the adjacent Westerschelde estuary. M. leidyi occurred from August to December, but was never found more than 30 km offshore. Densities were generally low (average 0.8 ± SD 2.8 ind m-3) compared to other invaded European systems. Highest densities of M. leidyi were found in the semi-enclosed basin (port of Oostende; 18.4 ind m-3) and Westerschelde estuary (1.9 ind m-3). The presence of larvae and sudden appearance of high numbers across the size distribution in August indicated that ports and estuaries may act as sources, populating the adjacent coastal area. The zero-inflated logistic regression model showed that there is a higher chance of finding M. leidyi (presence) when temperature declines from late summer onwards. Combined with a negative binomial regression, our model suggests that increasing M. leidyi densities are associated with decreasing autumn temperatures, low wave height (low energetic systems) and low dissolved oxygen concentrations Although densities remained relatively low since its first appearance in 2007, a permanent population seems to be established in Belgian waters. As population outbursts may occur with only a small change in environmental parameters, further monitoring of this notorious invasive species is recommended.

International audience; The effect of short and long-term induced anoxia on a benthic nematode community and its potential for recovery after reoxygenation were investigated in an in situ experiment on a silty-sand bottom in the Gulf of Trieste, the northern Adriatic Sea. Anoxia was created artificially by three underwater benthic Plexiglas chambers at a depth of 24m. Treatments lasted for 2, 23 and 307 days. Control samples (Normoxia) were taken on 3 (Normoxia 1) and 25 (Normoxia 2) August 2010 outside the chambers (4–5m further). After opening the chambers, recovery cores were taken after 7 days (Anoxia 2D), 30 days (Anoxia 23D) and 90 days (Anoxia 307D).Our results revealed that short-term anoxia (Anoxia 2D) did not affect nematode total density and diversity, community structure and their vertical distribution in the sediment. However, total and vertical nematode density, species richness and diversity decreased at 23 days and decreased further at 307 days anoxia. Some nematode species like Metalinhomoeus effilatus, Paralinhomoeus caxinus and Terschellingia longicaudata even survived at 307 days anoxia treatment. Our results also demonstrated that nematode community exposed to 23 days anoxia did not recover after 30 days sediment reoxygenation but, a full recovery was observed after 90 days for nematode community exposed to 307 days anoxia.Feeding type contribution (functional aspect) of the nematode community also changed at the anoxia treatments and during the recovery process. This change was most drastic at the Anoxia 23D and 307D treatments. At both Normoxia and Anoxia 2D treatments, selective deposit feeders (1A), non-selective deposit feeders (1B) and epistrate (diatom) feeders (2A) nematodes were observed in the dominant nematode community. Epistrate feeders disappeared from in the Anoxia 23D treatment epistrate and also selective deposit feeders did not belong to the dominant nematode species in the Anoxia 307D treatment. After the recovery process, epistrate feeders and selective deposit feeding nematodes reappeared again amongst the dominant nematode species after 30 and 90 days of recovery, respectively.

The loss or decline in population size of key species can instigate a cascade of effects that have implications for interacting species, therewith impacting biodiversity and ecosystem functioning. We examined how top–down and bottom–up interactions may mediate knock-on effects of a coastal deposit-feeding clam, Macomona liliana (hereafter Macomona), on sandflat meiobenthos densities. Therefore we manipulated densities of Macomona in combination with predator exclusion and experimental shading that was expected to alter microphytobenthos biomass. We show that Macomona regulated densities of meiobenthic (38–500 μm) nematodes, copepods, polychaetes, turbellarians, and ostracodes during the three months of incubation via indirect mechanisms. Predator pressure on Macomona by eagle rays (Myliobatis tenuicaudatus) was found to have a negative effect on densities of some meiobenthic taxa. Furthermore, experimental shading resulted in the loss of a positive relation between Macomona and microphytobenthos biomass, while concurrently increasing the density of some meiobenthic taxa. We suggest that this observation can be explained by the release from bioturbation interference effects of the cockle Austrovenus stutchburyi that was found to thrive in the presence of Macomona under non-shaded conditions. Our results highlight the importance of interactions between macrofaunal bioturbation, microphyte biomass, sediment stability, and predation pressure for the structuring of benthic communities. This experiment illustrates that manipulative field experiments may be particularly suitable to study such multiple indirect mechanisms that regulate ecosystem diversity and related functioning because such approaches may best capture the complex feedbacks and processes that determine ecosystem dynamics.

The presence of large densities of the piston-pumping polychaete Lanice conchilega can have important consequences for the functioning of marine sediments. It is considered both an allogenic and an autogenic ecosystem engineer, affecting spatial and temporal biogeochemical gradients (oxygen concentrations, oxygen penetration depth and nutrient concentrations) and physical properties (grain size) of marine sediments, which could affect functional properties of sediment-inhabiting microbial communities. Here we investigated whether density-dependent effects of L. conchilega affected horizontal (m-scale) and vertical (cm-scale) patterns in the distribution, diversity and composition of the typical nosZ gene in the active denitrifying organisms. This gene plays a major role in N2O reduction in coastal ecosystems as the last step completing the denitrification pathway. We showed that both vertical and horizontal composition and richness of nosZ gene were indeed significantly affected when large densities of the bio-irrigator were present. This could be directly related to allogenic ecosystem engineering effects on the environment, reflected in increased oxygen penetration depth and oxygen concentrations in the upper cm of the sediment in high densities of L. conchilega. A higher diversity (Shannon diversity and inverse Simpson) of nosZ observed in patches with high L. conchilega densities (3,185–3,440 ind. m-2) at deeper sediment layers could suggest a downward transport of NO3− to deeper layers resulting from bio-irrigation as well. Hence, our results show the effect of L. conchilega bio-irrigation activity on denitrifying organisms in L. conchilega reefs.

Anthropogenic CO2 emissions are rapidly changing seawater temperature, pH and carbonate chemistry. This study compares the embryonic development under high pCO2 conditions across the south-north distribution range of the marine clam Limecola balthica in NW Europe. The combined effects of elevated temperature and reduced pH on hatching success and size varied strongly between the three studied populations, with the Gulf of Finland population appearing most endangered under the conditions predicted to occur by 2100. These results demonstrate that the assessment of marine faunal population persistence to future climatic conditions needs to consider the interactive effects of co-occurring physico-chemical alterations in seawater within the local context that determines population fitness, adaptation potential and the system resilience to environmental change.

The development of offshore wind farms (OWFs) in the North Sea has increased considerably to create alternatives for fossil fuel energy. Activities related to the construction of OWFs, in particular gravity-based foundations (GBFs), are mainly associated to dredging, causing direct effects to the macrofauna in the seabed. The sediment characteristics and macrofauna were studied before and after construction (2005–2010) of six GBFs in an OWF in the Belgian part of the North Sea. We distinguished natural from anthropogenic-related fluctuations in macrofaunal communities by analysing a long-term dataset (1980–2012). The analysed sandbanks are characterised by sandy substrates and a community with low species abundance (180–812 ind m-2) and diversity (6–15 species per 0.1 m2). Strong temporal variations were observed possibly related to variable weather conditions in the area. Significant differences in community composition were observed due to the installation of six GBFs in the construction year of the OWF followed by a rapid recovery a year later and confirmed by the benthic ecosystem quality index BEQI. Even though the construction of GBFs creates a physical disturbance to the seabed, the macrobenthic community of these sediments have illustrated a fast recovery potential.

The Belgian coastal zone hosts a complex of space-use and resource-use activities with a myriad of pressures. Specifically at the beaches, predictions on sea-level rise, storms and flood risk from the North Sea have led to several big coastal defence projects. Management of sandy beaches is a multi-faceted and complex endeavor, where the interests of several stakeholders need to be combined.In this paper, we used the marine biological valuation (BV) method in order to (1) analyse the spatial structure of the intertidal and shallow subtidal Belgian coastal zone; and (2) explore the applications of BV for an ecosystem-based approach to marine spatial planning of two space-use conflicts at the Belgian coast, being flood protection, by means of beach nourishment, and nature conservation.The biological value was assessed with a focus on a detailed and integrated dataset (1995 – 2011), gathering all available ecological information on macrobenthos, epibenthos, hyperbenthos and birds. The 67 km Belgian coastline was divided into an across-shore intertidal and shallow subtidal subzone while the width of the along-shore subzones comprises 250 m for benthic components and wider distances of 3 km for the birds. The intrinsic biological value of each subzone was calculated using the BV method and the pertained score, ranging from very low to very high, was plotted accordingly in order to obtain a marine biological valuation map (BVM).Following trends in BV along the Belgian coastline were detected: (1) a strong mosaic pattern of BV along the coastline; (2) a clear lack of (benthic) data at the eastern part of the Belgian coast; (3) a rather high biological value score for around 70 % of the shallow part of the subzones, compared with the intertidal part; (4) a high/very high biological values found in intertidal zones located immediately to the east of the harbours Nieuwpoort, Oostende and Zeebrugge.A detailed analysis of protected areas and areas under coastal flood risk indicates that the use of BVMs is very promising in order to differentiate between several impact values. BV can therefore be used as a management tool by local decision makers and can allow for the integration of ‘natural/ecological values’ at an early stage of policy implementation.

Rhynchonema Cobb, 1920 is a genus with worldwide distribution. It is found in diverse coastal environments ranging from brackish water to exposed beaches in intertidal and low subtidal zones, from clay to coarse sand and in sediments under seagrass beds. In this study we describe two new tropical species from Northeast South America: Rhynchonema cemae sp.n. and R. veronicae sp. n. from Olinda’s Isthmus, Pernambuco, Brazil. These two species are mainly characterized by the shapes of the spicules and gubernaculum, which are described here for the first time. The two species can be differentiated primarily on the basis of the spicules, which in R. cemae are symmetrical, fine and long, while in R. veronicae they are asymmetrical, more robust and shorter. We describe for the first time the presence of Rhynchonema species on the east side of South America and provide a review of the genus and a polytomous identification key. Our review of the literature and construction of a polytomous key demonstrated that most of the species descriptions are incomplete.

Few studies have examined discard survival in beam trawl fisheries, especially in 4 m beam trawl fisheries using chain mats and limited haul durations. This so-called “eurocutter” fishery is carried out by beam trawlers with an engine power ≤221 kW and is allowed in the 6 to 12 nm zone in contrast to larger beam trawlers which operate solely outside of the 12 nm limit. Chain mat beam trawling was developed to prevent large boulders from entering the net, and is typically conducted at lower fishing speed than tickler chain beam trawling. This study obtained short-term survival estimates for this “eurocutter” fishery by monitoring post-capture mortality in tank-held organisms. Survival was high to very high (>75%) for benthic invertebrates, but not for fish. All examined whiting (Merlangius merlangus) and pouting (Trisopterus sp.) died. Only 14% of sole (Solea solea) survived to 91 h of observation, and 48% of plaice (Pleuronectes platessa) to 77 h. The survival probability was higher for cod (Gadus morhua) (66% to 88 h) and skates (Rajidae) (72% to 80 h). However, the mortality rate had not stabilized within the period of observation. Survival models were used to estimate the minimum duration of captivity required to properly evaluate short-term survival, and to investigate the role of physical injuries and other pertinent covariates (catch weight, fish length, fishing depth, salinity, sea surface temperature, air temperature and fishing trip) in determining fish discard survival. The results of this study indicate a high variability in discard survival amongst taxa and highlight that physical injuries when taken alone are a limited proxy for survival of 4 m beam trawl discards and that small fish specimens have a limited chance of surviving discarding.

The growing development of offshore wind energy installations across the North Sea is producing new hard anthropogenic structures in the natural soft sediments, causing changes to the surrounding macrobenthos. The extent of modification in permeable sediments around a gravity based wind turbine in the Belgian part of the North Sea was investigated in the period 2011 – 2012, along four gradients (south-west, north-east, south-east, north-west). Sediment grain size significantly reduced from 427 µm at 200 m to 312 ± 3 µm at 15 m from the foundation along the south-west and north-west gradients. The organic matter content increased from 0.4 ± 0.01% at 100 m to 2.5 ± 0.9% at 15 m from the foundation. The observed changes in environmental characteristics triggered an increase in the macrobenthic density from 1390 ± 129 ind m-2 at 200 m to 18 583 ± 6713 ind m-2 at 15 m together with an enhanced diversity from 10 ± 2 at 200 m to 30 ± 5 species per sample at 15 m. Shifts in species dominance were also detected with a greater dominance of the ecosystem-engineer Lanice conchilega (16–25%) close to the foundation. This study suggests a viable prediction of the effects offshore wind farms could create to the naturally occurring macrobenthos on a large-scale.

Biodiversity conservation often focuses on threatened or rare species. While this structural asset of biodiversity is indeed important, the functional diversity aspect has to be considered as an even more important criterion for marine management and conservation. This paper explores the use of functionally important ecosystem engineers in North Sea management approaches. An overview of several North Sea ecosystem engineering species shows that ecosystem engineers such as bulldozing echinoderms and burrowing shrimps as well as bio-irrigating polychaetes are bound to receive more attention in the management of marine areas than they do now, given their important structuring aspect in associated fauna and implications for seafloor ecosystem functioning. The use of ecosystem engineers could contribute considerably to the concept of Ecosystem-Based Management in the marine realm. This is clearly illustrated in the present case study of the bio-irrigating polychaete Lanice conchilega. Since this species manifests both autogenic and allogenic ecosystem engineering properties, the management of human activities that affect common species such as L. conchilega reefs can enhance protection of the entire local ecosystem. In the North Sea, some commonly occurring ecosystem engineers and their engineered habitat can be protected under the European Habitats Directive and the EU Marine Strategy Framework Directive. Copyright © 2014 John Wiley & Sons, Ltd.

This study explores the relation between sediment composition and intertidal macrobenthos populations in the Zwin nature reserve (Belgium and The Netherlands), a tidal lagoon that is included in the Ramsar list of wetlands of international importance and has been designated as Natura 2000 area, among others due to its function as wintering habitat for shorebirds that feed upon macrobenthic invertebrates. Species response models show highest biomass of these prey species in organically enriched cohesive sediments and a distinct decline in probability of occurrence for most species in coarse sediments. Further, the biomass of macrobenthos declined between 2003 and 2010 in the extensive low intertidal inlet channel concurrent with the coarsening of the sediment over time in this hydrodynamically stressed habitat. In contrast, macrobenthos biomass increased in a sheltered shallow intertidal habitat that acted as a catchment area for finer sediments, therefore facilitating the succession towards a higher elevated habitat with salt marsh vegetation establishment. Hence, spatio-temporal sediment dynamics decreased site quality for intertidal predators due to a reduction in feeding areas over time, and a change in physical sediment properties that alter the macrobenthos species occurrence and population biomass. This study thus illustrates that sediment transport dynamics may affect the functioning of coastal shallow soft-sediment habitats, like coastal lagoons. The presented macrobenthos species response models provide a tool to assist in management actions that enable the conservation of cohesive low intertidal habitats that provide a high food supply to shorebirds, fish and macrocrustaceans.

Predation is known to play an important role in structuring communities. In rocky intertidal communities, both environmental variables and the structuring role of predation determine species zonation and distribution patterns. However, on intertidal sandy beaches, little is known on the presence and the role of predation. In this study, laboratory experiments were used to examine prey consumption, prey selectivity and predation pressure of the two main epibenthic predators, being shrimp and juvenile flatfish, present on the intertidal beach at high tide. Results show that macrobenthos is important in the diet of these epibenthic predators and that prey selectivity is present. As predation pressure on the intertidal beach is high, predation is probably an important structuring factor for the sandy beach macrobenthos community. Hence, the macrobenthos zonation pattern is likely to be steered by the combination of abiotic and biotic factors: while the upper limit of a species zone is defined by the species physiological response to abiotic environmental variables, the lower limit is defined by biotic factors such as predation pressure. Furthermore, the intertidal zone functions as an important nursery area for commercially important species like shrimp and flatfish.

In the next 10–20 years, thousands of wind turbines will be present in the North Sea. In this paper, we investigate the impact of these windmill artificial reefs (WARs) on the ecology of benthopelagic fish. More specifically we will try to resolve the attraction-ecological trap-production issue for Atlantic cod and pouting at WARs and link the information to opportunities for fisheries activities. From 2009 until 2012 the behavioural ecology of Atlantic cod and pouting was investigated at WARs in the Belgian part of the North Sea (BPNS). Information on length-frequency distribution, diet, community structure and movements were combined to gain insights on the behavioural ecology and to unravel whether production occurs. We demonstrated that specific age groups of Atlantic cod and pouting are seasonally attracted towards the WARs, that they show high site fidelity and feed upon the dominant epifaunal prey species present. Growth was observed throughout the period the fishes were present. Production on a local scale can be assumed. On a regional scale however, no changes were observed yet. Based on the acquired knowledge we judged that no fisheries activities should be allowed inside the offshore wind farms in the BPNS.

Atlantic cod ( Gadus morhua ) is a commercially important fish species suffering from overexploitation in the North-East Atlantic. In recent years, their natural environment is being intensively altered by the construction of offshore wind farms in many coastal areas. These constructions form artificial reefs influencing local biodiversity and ecosystem functioning. It has been demonstrated that Atlantic cod is present in the vicinity of these constructions. However, empirical data concerning the diel activity and feeding behaviour of Atlantic cod in the vicinity of these artificial reefs is lacking. Atlantic cod has a flexible diel activity cycle linked to spatio-temporal variations in food availability and predation risk. In this study we integrated acoustic telemetry with stomach content analysis to quantify diel activity and evaluate diel feeding patterns at a windmill artificial reef (WAR) in the Belgian part of the North Sea. Atlantic cod exhibited crepuscular movements related to feeding activity; a 12 h cycle was found and the highest catch rates and stomach fullness were recorded close to sunset and sunrise. It is suggested that the observed diel movement pattern is related to the prey species community and to predation pressure. Foraging at low ambient light levels (i.e. at dusk and dawn) probably causes a trade-off between foraging success and reducing predation pressure. Fish did not leave the area in-between feeding periods. Hence other benefits (i.e. shelter against currents and predators) besides food availability stimulate the aggregation behaviour at the WARs.

This manuscript presents the mesozooplankton community structure and its spatial and temporal variabilities in the Belgian part of the North Sea (BPNS), a first thorough study on this topic in nearly 40 years. Monthly sampling campaigns at ten stations in the BPNS in 2009 and 2010 yielded a total of 137 mesozooplankton taxa (46 holoplanktonic, 50 meroplanktonic and 41 tychoplanktonic), of which nine species had never been reported in the area. Smaller neritic copepods, especially Temora longicornis and Acartia clausi, were present in all samples and dominated zooplankton densities (66%), together with the appendicularian Oikopleura dioica (10%). They were joined by high numbers of meroplanktonic echinoderm larvae (9%) in spring and summer. Based on diversity alone, the mesozooplankton could be typified as one neritic zooplankton community, due to the ubiquitous presence in time and space of the dominant copepods. Yet, these neritic species were often joined by low numbers of oceanic species that are occasionally imported with the inflow of Atlantic oceanic water in the BPNS. Based on a combination of abundance and diversity, our results indicate distinct seasonal and spatial distribution patterns in the mesozooplankton. Months with highest average densities were May, June and July, lowest densities were noted in December and January. Only limited long-term zooplankton data are available for the BPNS from the Continuous Plankton Recorder surveys or the long-term monitoring stations in the vicinity of our research area. However, our data suggest that nowadays zooplankton species appear earlier in the BPNS, comparable with other areas in the North Sea. Densities varied between 150 and 15,000 ind.m− 3, and averaged highest at midshore stations, then nearshore and offshore. This is partially comparable with the spatial patterns recorded for other ecosystem components, such as demersal fish, epibenthos and macrobenthos, of which densities peak in a stretch almost parallel to but some miles away from the coastline in the BPNS.

The construction of wind farms introduces artificial hard substrates in sandy sediments. As Atlantic cod (Gadus morhua) and pouting (Trisopterus luscus) tend to aggregate in order to feed around these reefs, energy profiling and trophic markers were applied to study their feeding ecology in a wind farm in the Belgian part of the North Sea. The proximate composition (carbohydrates, proteins and lipids) differed significantly between liver and muscle tissue but not between fish species or between their potential prey species. Atlantic cod showed to consume more energy than pouting. The latter had a higher overall energy reserve and can theoretically survive twice as long on the available energy than cod. In autumn, both fish species could survive longer on their energy than in spring. Polyunsaturated fatty acids were found in high concentrations in fish liver. The prey species Jassa and Pisidia were both rich in EPA while Jassa had a higher DHA content than Pisidia.Energy profiling supported the statement that wind farm artificial reefs are suitable feeding ground for both fish species. Sufficient energy levels were recorded and there is no indication of competition.

article i nfo Within coastal nurseries, the distribution of juvenile flatfish may depend on small-scale habitat variability. The presence of ecosystem engineers is known to have important impacts in coastal sediments. Lanice conchilega is a well-known marine ecosystem engineer of shallow soft bottom ecosystems, shaping the macrobenthic community and attracting flatfish. The present study examines the relation between juvenile flatfish and L. conchilega reefs through two experiments. In a field experiment in the Dutch part of the North Sea, the benthic habitat is evaluated by comparing relative differences in numbers of juvenile flatfish between ecosystem engineered habitats and adjacent bare sand (i.e. non-ecosystem engineered) habitats. The hypothetical shelter seeking behaviour was further examined using stomach content analyses. Results show that juvenile plaice Pleuronectes platessa was the dominant species within the tube worm habitat and the species selects specifically for this biogenic habitat. This selection was explained as feeding behaviour. In a complementary laboratory study, food was excluded and the shelter function of the ecosystem engineered habitat was investigated. This experiment quantifies the selection for this habitat by juveniles of the common sole Solea solea. Results from the flume experiment, manipulating the number of tube worms, show that distribution of sole was not random when current velocities are high. The selected habitat is the one with low density tube worm aggregations. Overall, we conclude that structuring benthos plays an important role for juvenile flatfish, both as refuge and as feeding ground. © 2012 Published by Elsevier B.V.

Publicly reported statistics on the production of fisheries refer to ‘landings’ as opposed to ‘catch’. However, well-informed decisions and evaluation of the impacts of fisheries on ecosystems must be based on total removals, so including the part of the catch that is discarded at sea or not reported as landings. Total removals by Belgian fisheries from all ICES fishing areas and from the Belgian part of the North Sea (BNS) from 1929 to 2010, were reconstructed by including unreported and misreported landings of the commercial fleet, unreported landings by the recreational and artisanal/subsistence fisheries and by estimating discards for the most important fisheries. Total reconstructed removals were estimated at 5.2 million t or 42% higher than the 3.7 million t publicly reported over this period. Unreported landings and discards were estimated to represent respectively 3.5% (0.2 million t) and 26% (1.3 million t) of these total reconstructed removals. The reconstructed total removals on the BNS were estimated to be 55% higher than the 0.8 million t publicly reported over this period. Discards represent an average annual of 34% of the total removals on the BNS over the entire period. The results suggest that since the 2000s, approximately 50% of all Belgian removals from its EEZ are unreported landings and discards (IUU). The unreported landings and discards are increasingly taken by non-commercial, small-scale (

Because offshore wind energy development is fast growing in Europe it is important to investigate the changes in the marine environment and how these may influence local biodiversity and ecosystem functioning. One of the species affected by these ecosystem changes is Atlantic cod (Gadus morhua), a heavily exploited, commercially important fish species. In this research we investigated the residency, site fidelity and habitat use of Atlantic cod on a temporal scale at windmill artificial reefs in the Belgian part of the North Sea. Acoustic telemetry was used and the Vemco VR2W position system was deployed to quantify the movement behaviour. In total, 22 Atlantic cod were tagged and monitored for up to one year. Many fish were present near the artificial reefs during summer and autumn, and demonstrated strong residency and high individual detection rates. When present within the study area, Atlantic cod also showed distinct habitat selectivity. We identified aggregation near the artificial hard substrates of the wind turbines. In addition, a clear seasonal pattern in presence was observed. The high number of fish present in summer and autumn alternated with a period of very low densities during the winter period.

The understanding of the role of nature conservation (NC) is used to illustrate how an integrated and sustainable approach to decision-making could be developed for planning and managing activities in the marine environment. The need for NC to be integrated in the marine spatial planning (MSP) decision-making process is highlighted in various initiatives around the world. However none of these initiatives describes a commonly applicable framework to achieve this goal. The plethora of interpretations regarding the meaning, role and position of NC in planning, makes such an attempt more complex. A good starting point in order to develop such a process is to answer the question: how NC can contribute to the achievement of sustainability in the context of MSP? In the present study the different ways that NC has been interpreted over time are explored and several definitions are analyzed, concluding that there is currently no common approach to NC in MSP initiatives. Therefore it is indicated that NC should be treated as a means to achieve good environmental status of the ecosystem, based on its spatial, economic and conflict resolution dimensions, characteristics that are common among all marine uses. Consequently, it is proposed that NC at sea should be put in a central position during the MSP processes. A schematic presentation of the concept is provided in this paper.

a b s t r a c t Intensive exploitation of the marine environment by mankind can alter the natural habitat of marine organisms drastically. The addition of artificial hard substrates (e.g. shipwrecks and wind turbine foun- dations) to soft-sediment sandy bottoms is a pervasive example of an anthropogenic habitat change. To investigate the importance of hard substrate habitats for demersal fish species, we studied the spatio-temporal variability for two commercially important species, Atlantic cod (Gadus morhua) and pouting (Trisopterus luscus), from 2009 to 2011 at three different habitats in the Belgian part of the North Sea (BPNS), i.e. windmill artificial reefs (WARs), shipwrecks and sandy bottoms. Our results showed that population densities of both species were highly enhanced at the hard substrate habitats in comparison to the sandy sediments. The highest catch-per-unit effort values for both species were recorded around the WARs, which indicated distinct aggregation around the wind turbine foundations. In addition, the observed aggregation at the hard substrates differed between seasons. Highest popu- lation densities were observed in summer and autumn, i.e. the most intensive feeding period for both fishes. We conclude that the distribution and behaviour of Atlantic cod and pouting is affected by the presence and complexity of artificial hard substrates on the seabed.

Ecosystem engineers are organisms that modulate natural resources enabling the survival of other species. They drive environmental change and contribute to several coastal functional attributes such as landscape heterogeneity, sedimentary processes, and coastal protection. Our study focuses on the case of Lanice conchilega, a tube-building ecosystem engineer whose aggregations impact sedimentary processes. This polychaete forms biogenic tube aggregations distributed on the coasts of the northern hemisphere from the shallow intertidal to depths of 1900 m. The aggregations engineer sedimentary processes autogenically by altering water flow at the benthic-boundary layer, and harbor highly diverse infaunal communities as a consequence. This study evaluates the relationships between intertidal L. conchilega aggregations and sedimentary processes at the intertidal zone of a sandy beach in northern France. Three experiments were executed to investigate (1) the effects of L. conchilega presence on sedimentary processes, as well as (2) the impacts of sedimentation on L. conchilega survival and patch growth, and (3) assess small-scale spatial heterogeneity in density and ecosystem engineering in L. conchilega aggregations. Weekly estimations of sedimentary properties in-situ showed that net deposition is significantly higher inside L. conchilega aggregations than in bare sand; whereas sediment mixing depth is noticeably reduced in comparison and regardless of patch tidal height. Variations in tube density above 3200 ind m-2 did not significantly impact sedimentary properties suggesting that the relationship between flow attenuation and tube density is nonlinear. In-situ monitoring of L. conchilega aggregations revealed different temporal trends for tube density and EPS content at the sediment surface between the center and edges of patches. This hints at the presence of environmental gradients within aggregations that may cause small-scale spatial heterogeneity. Finally, laboratory experiments showed significantly higher mortality rates and tube building activity in the presence of sediment deposition between 5 cm and 12 cm in column height. Results are in agreement with previous research suggesting that a positive feedback between sedimentation and tube-building activity drives the vertical expansion of patches. However, vertical expansion may be limited by deposition-induced mortality, thereby controlling population abundance.

Ecosystem engineers contribute to ecosystem functioning by regulating key environmental attributes, such as habitat availability and sediment biogeochemistry. While autogenic engineers can increase habitat complexity passively and provide physical protection to other species, allogenic engineers can regulate sediment oxygenation and biogeochemistry through bioturbation and/or bioirrigation. Their effects rely on the physical attributes of the engineer and/or its biogenic constructs, such as abundance and/or size. The present study focused on tube aggregations of a sessile, tube-building polychaete that engineers marine sediments, Lanice conchilega. Its tube aggregations modulate water flow by dissipating energy, influencing sedimentary processes and increasing particle retention. These effects can be influenced by temporal fluctuations in population demographic processes. Presently, we investigated the relationship between population processes and ecosystem engineering through an in-situ survey (1.5 years) of L. conchilega aggregations at the sandy beach of Boulogne-sur-Mer (France). We (1) evaluated temporal patterns in population structure, and (2) investigated how these are related to the ecosystem engineering of L. conchilega on marine sediments. During our survey, we assessed tube density, demographic structure, and sediment properties (surficial chl-a, EPS, TOM, median and mode grain size, sorting, and mud and water content) on a monthly basis for 12 intertidal aggregations. We found that the population was mainly composed by short-lived (6-10 months), small-medium individuals. Mass mortality severely reduced population density during winter. However the population persisted, likely due to recruits from other populations, which are associated to short- and long-term population dynamics. Two periods of recruitment were identified: spring/summer and autumn. Population density was highest during the spring recruitment and significantly affected several environmental properties (i.e. EPS, TOM, mode grain size, mud and water content), suggesting that demographic processes may be responsible for periods of pronounced ecosystem engineering with densities of approx. 30 000 ind m-2.