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How the implementation of the European Commission's landing obligation (LO) would affect French vessels of the mixed demersal fishery in the Eastern English Channel was hardly foreseen because of the diversity of vessel characteristics and strategies in the area. Assessing whether the vessels would be able to mitigate the bio-economic impacts of LO and avoid choke situations through exemptions, by changing their fishing patterns or by avoiding areas, required fine scale spatio-temporal modelling of fish and fleet dynamics and of resulting technical interactions. We conducted a bio-economic impact assessment for seven scenarios of mitigation focussing on the differences across fleets and the impact of fleet spatial behavioural flexibility. We found that netters rapidly benefited from the LO as opposed to trawlers and that exemptions helped mitigate the economic loss with limited biomass loss. The avoidance strategies proved to be efficient in reducing unwanted catch of whiting and enabled unexpected protection of juvenile sole. Sensitivity analysis on the drivers of fishing behaviour indicated that the ability and efficiency of adapting fishing patterns depended on main gear and vessel size. Results evidenced the difficult trade-offs LO implies among stocks, fish stages, fleets, and even sub-regions, beyond the usual biological vs. economic contrasts. [ABSTRACT FROM AUTHOR]

This study examined some of the spatial patterns and temporal dynamics of species targeting and discarding, for the French bottom trawlers operating in the eastern English Channel, building on spatial overlaps (or mismatches) between fishing effort, survey-based biomass or abundance indices and discard rates. We first identified that cuttlefish (Sepia officinalis), squids (Loligo sp.) and, to a lesser degree, striped red mullet (Mullus surmuletus), and seabass (Dicentrarchus labrax) were the main targets, while fishing for historically important species was less attractive. This result was broadly in accord with catch compositions, although mackerel (Scomber scombrus) targeting was possibly underestimated. We also showed that the distributions of fishing effort and of undersized herring, plaice, and whiting did not overlap. Although fishing effort covered fishing grounds populated with undersized horse mackerel, the proportion of undersized individuals in the discards was small. Plaice and whiting discard rates overlapped in space with undersized abundance indices. Fishing effort may have avoided spatial units with potentially high plaice discard rates, which may have been driven by large proportions of undersized fish, but also by restricted access to coastal area. Overall, the EU Landing Obligation had limited effects on fishing effort allocation relative to either undersized abundance or discard rates distributions. [ABSTRACT FROM AUTHOR]

It has been established from previous studies that chlorophyll- a surface concentration has been declining in the eastern English Channel. This decline has been attributed to a decrease in nutrient concentrations in the rivers. However, the decrease in river discharge could also be a cause. In our study, rivers outflows and in-situ data have been compared to time series of satellite-derived chlorophyll- a concentrations. Dynamic Linear Model has been used to extract the dynamic and seasonally adjusted trends of several environmental variables. The results showed that, for the 1998–2019 period, chlorophyll- a levels stayed significantly lower than average and satellite images revealed a coast to offshore gradient. Chlorophyll- a concentration of coastal stations appeared to be related to the declining fluxes of phosphate while offshore stations were more related to nitrate-nitrite. Therefore, we can exclude that the climate variability, through river flows alone, has a dominant effect on the decline of chlorophyll- a concentration. • Chlorophyll declined during two decades in the Eastern English Channel. • Satellite images revealed coast to offshore chlorophyll decline gradient. • Changes in river flow were a minor driver of chlorophyll decline. • Phosphate was main explanatory variable for coastal stations chlorophyll decrease. • Nitrate-nitrite were related to offshore stations chlorophyll decrease. [ABSTRACT FROM AUTHOR]

Coastal and estuarine (CE) areas are essential fish habitats; they act as nurseries for a large proportion of species of fisheries interest but face high levels of cumulative anthropogenic pressures. A comprehensive analysis of the impacts of CE nursery habitat degradation at the population scale for exploited fish species is still lacking. Our study aims to assess the effects of CE nursery habitat restoration for four species of main fisheries of interest in the Eastern English Channel (EEC): sole (Solea solea), plaice (Pleuronectes platessa), whiting (Merlangius merlangus) and seabass (Dicentrarchus labrax). A generic age- and stage-based population model representing the dynamics of exploited populations and integrating the dependence of recruitment on juvenile habitats was used. This model allowed us to evaluate the combined effect of nursery degradation and fishing pressure on stock dynamics. The model was parameterized for each of the four species based on stock assessment outputs in the EEC and literature and then used to simulate equilibrium states under different habitat restoration scenarios. These scenarios were built using previous estimates of both surface area loss and decrease in marine juvenile fish density in CE habitats facing anthropogenic pressures in the EEC. Surface area and quality restoration enhanced both biomass and sustainable catch levels for the four species in the EEC. The species with higher concentrations in shallow nursery areas were the most sensitive to habitat restoration. The response also depended on life history traits, i.e., species with lower resilience to fishing pressure (i.e., steepness) exhibited a stronger response to habitat quality scenarios. • The effects of nursery habitat restoration were assessed for four key fisheries species in the Eastern English Channel. • Potential restoration gains were substantial, up to more than 50% of spawning biomass at maximal sustainable yield for the most shallow nursery-dependent species. • Species with higher concentrations in shallow nurseries were the most sensitive to habitat restoration. • Contrasts in life history traits lead to species-specific responses: a lower resilience to fishing pressure induces a stronger response. [ABSTRACT FROM AUTHOR]

Abstract An accurate representation of the spatial structure of marine fish populations is a prerequisite for unbiased stock assessment, to build appropriate management measures. The common sole (Solea solea, L.) of the Eastern English Channel (EEC) is a commercial flatfish species, whose stock is currently assessed as a single homogeneous population and has been overexploited over the last decade. Previous studies have highlighted the stock's low connectivity and the lack of understanding in sub-adults and adults mixing between putative subunits, raising the issue of a potential spatial structure of this stock. Here, we examined evidence of spatial structure by analyzing spatiotemporal patterns of length and density-at-age using time series (1989–2015) obtained from a scientific survey (UK-BTS). We tested for various hypotheses of spatial structure, based on both scientific and expert knowledge, including three isolated subunits, their combination, and no spatial structure. We combined two sets of analyses: (1) a selection of the von Bertalanffy growth model with spatial effects capturing the most accurate spatial structure of the stock and the analysis of long-term spatial patterns (gradients, trends, synchrony) in growth parameters; and (2) an analysis of the synchrony among density-at-age time series between spatial subunits. Growth analysis revealed a spatial structure in three subunits (i.e. the southwestern, northeastern and English parts of the EEC) and an overall decline of length-at-age, suggesting Fishery-Induced Evolution. The synchrony analysis revealed high spatiotemporal integrity at the level of the southwestern subunit of the EEC. Our two analyses thus detected a lasting signal of spatial stock structure with a probable isolation of the southwestern subunit from the rest of the EEC. Future research should build on our study by investigating the connectivity of sole throughout its entire life cycle, to improve stock assessment and fishery management. Highlights • Long-term spatial structure was investigated by combining analyses of growth and abundance at age over long time series. • Long-term spatial differences in von Bertalanffy growth parameters revealed the existence of lasting spatial structure. • Length-at-age declined with spatial differences in slopes, suggesting fishery-induced evolution and contrasted exploitation. • Synchrony in density-at-age time series indicated high spatiotemporal integrity of the SW subunit, suggesting its isolation. • Growth and density-at-age analyses were consistent to detect isolation of the SW subunit from the rest of the stock. [ABSTRACT FROM AUTHOR]

In organic-rich shallow habitats, benthic macrofauna is known to play a major role in the geochemical functioning of surficial sediments through its metabolism, as well as its bioirrigation and/or bioturbation activity. In this paper, the effects of benthic macrofauna on metabolic fluxes at the sediment-water interface were studied at four dates, from winter to late summer, on two major macrobenthic communities of the eastern English Channel (macrotidal system): the fine sand Abra alba community (2 stations) and the sandy gravel Ophiothrix fragilis community (1 station). Oxygen and ammonium fluxes showed temporal changes that could be attributed to the variation of sea water temperature. Once the effect of temperature removed (using Q 10  = 2.5), the average fauna mediated fluxes (F Fauna ) represented respectively 77% and 76% of average total fluxes. Considering the whole dataset, species number and biomass showed a significant correlation with fauna mediated fluxes of O 2 and NH 4 + , while the relationships with abundance were not significant. The species composition of the community might influence ecosystem functioning, but in the present study, functional groups have a very poor relationship with F Fauna (O 2 ) and F Fauna (NH 4 + ). Despite the presence of engineer species, establishing general and simple rules to link macrofaunal parameters to functional attributes remains very difficult, suggesting that communities rather followed the idiosyncrasy and rivet hypothesis. [ABSTRACT FROM AUTHOR]

Asthenognathus atlanticus Monod, 1932, is reported here for the first time in the area around Dieppe-Le Tréport (Normandy coast in the eastern part of the English Channel). A total of 26 specimens were collected in 2015-2016 from fine and coarse sands at water depths between 12 and 25 m. Two specimens were found in the stomach of two thornback rays Raja clavata. The eastward progression of A. atlanticus is consistent with tidal residual currents in the English Channel. The period of global warming is likely favorable for this easterly progression, and the species could reach the southern part of the North Sea in a few years. Our observations in the eastern part of the English Channel also illustrate a new commensal association between the tubicolous polychaete C. variopedatus and the crab A. atlanticus, the latter being found in a variety of soft-bottom sediments ranging from muddy to coarse sands, in agreement with reports of its presence in the Rade de Cherbourg and the Bay of Seine. [ABSTRACT FROM AUTHOR]

The ecosystem model Atlantis was used to investigate the key dynamics and processes that structure the Eastern English Channel ecosystem, with a particular focus on two commercial flatfish species, sole ( Solea solea ) and plaice ( Pleuronectes platessa ). This complex model was parameterized with data collected from diverse sources (a literature review, survey data, as well as landings and stock assessment information) and tuned so both simulated biomass and catch fit 2002–2011 observations. Here, the outputs are mainly presented for the two focus species and for some other vertebrates found to be important in the trophic network. The calibration process revealed the importance of coastal areas in the Eastern English Channel and of nutrient inputs from estuaries: a lack of river nutrients decreases the productivity of nursery grounds and adversely affects the production of sole and plaice. The role of discards in the trophic network is also highlighted. While sole and plaice did not have a strong influence on the trophic network of vertebrates, they are important predators for benthic invertebrates and compete for food with crustaceans, whiting ( Merlangius merlangus ) and other demersal fish. We also found that two key species, cod ( Gadus morhua ) and whiting, thoroughly structured the Eastern English Channel trophic network. [ABSTRACT FROM AUTHOR]

The link between harmful algal blooms, phytoplankton community dynamics and global environmental change is not well understood. To tackle this challenging question, a new method was used to reveal how phytoplankton communities responded to environmental change with the occurrence of an harmful algae, using the coastal waters of the eastern English Channel as a case study. The great interannual variability in the magnitude and intensity of Phaeocystis spp. blooms, along with diatoms, compared to the ongoing gradual decrease in anthropogenic nutrient concentration and rebalancing of nutrient ratios; suggests that other factors, such as competition for resources, may also play an important role. A realized niche approach was used with the Outlying Mean Index analysis and the dynamics of the species’ realized subniches were estimated using the Within Outlying Mean Indexes calculations under low (L) and high (H) contrasting Phaeocystis spp. abundance. The Within Outlying Mean Indexes allows the decomposition of the realized niche into realized subniches, found within the subset of habitat conditions and constrained by a subset of a biotic factor. The two contrasting scenarios were characterized by significantly different subsets of environmental conditions and diatom species (BV-step analysis), and different seasonality in salinity, turbidity, and nutrients. The subset L environmental conditions were potentially favorable for Phaeocystis spp. but it suffered from competitive exclusion by key diatom species such as Skeletonema spp., Thalassiosira gravida , Thalassionema nitzschioides and the Pseudo-nitzchia seriata complex. Accordingly, these diatoms species occupied 81% of Phaeocystis spp.'s existing fundamental subniche. In contrast, the greater number of diatoms, correlated with the community trend, within subset H exerted a weaker biological constraint and favored Phaeocystis spp. realized subniche expansion. In conclusion, the results strongly suggest that both abiotic and biotic interactions should be considered to understand Phaeocystis spp. blooms with greater consideration of the preceeding diatoms. HABs needs must therefore be studied as part of the total phytoplankton community. [ABSTRACT FROM AUTHOR]

Climate change not only alters ocean physics and chemistry but also affects the biota. Larval dispersal patterns from spawning to nursery grounds and larval survival are driven by hydrodynamic processes and shaped by (a)biotic environmental factors. Therefore, it is important to understand the impacts of increased temperature rise and changes in wind speed and direction on larval drift and survival. We apply a particle-tracking model coupled to a 3D-hydrodynamic model of the English Channel and the North Sea to study the dispersal dynamics of the exploited flatfish (common) sole ( Solea solea). We first assess model robustness and interannual variability in larval transport over the period 1995-2011. Then, using a subset of representative years (2003-2011), we investigate the impact of climate change on larval dispersal, connectivity patterns and recruitment at the nursery grounds. The impacts of five scenarios inspired by the 2040 projections of the Intergovernmental Panel on Climate Change are discussed and compared with interannual variability. The results suggest that 33% of the year-to-year recruitment variability is explained at a regional scale and that a 9-year period is sufficient to capture interannual variability in dispersal dynamics. In the scenario involving a temperature increase, early spawning and a wind change, the model predicts that (i) dispersal distance (+70%) and pelagic larval duration (+22%) will increase in response to the reduced temperature (−9%) experienced by early hatched larvae, (ii) larval recruitment at the nursery grounds will increase in some areas (36%) and decrease in others (−58%) and (iii) connectivity will show contrasting changes between areas. At the regional scale, our model predicts considerable changes in larval recruitment (+9%) and connectivity (retention −4% and seeding +37%) due to global change. All of these factors affect the distribution and productivity of sole and therefore the functioning of the demersal ecosystem and fisheries management. [ABSTRACT FROM AUTHOR]

The objective of this study is to analyse at fine scale the annual, seasonal and spatial distributions of several species in the Eastern English Channel (EEC). On the one hand, data obtained from scientific surveys are not available all year through, but are considered to provide consistent yearly and spatially resolved abundance indices. On the other hand, on-board commercial data do cover the whole year, but generally provide a biased perception of stock abundance. The combination of scientific and commercial catches per unit of effort (CPUEs), standardized using a delta-generalized linear model, allowed to infer spatial and monthly dynamics of fish distributions in the EEC, which could be compared with previous knowledge on their life cycles. Considering the scientific survey as a repository, the degree of reliability of commercial CPUEs was assessed with survey-based distribution using the Local Index of Collocation. Large scale information was in agreement with literature, especially for cuttlefish. Fine scale consistency between survey and commercial data was significant for half of the 19 tested species (e.g. whiting, cod). For the other species (e.g. plaice, thornback ray), the results were inconclusive, mainly owing to poor commercial data coverage and/or to particular aspects of the species biology. [ABSTRACT FROM AUTHOR]

Mercury (Hg) in fish can present a potential risk to wildlife and human consumers. Mercury levels were determined in 12 fish species and 2 invertebrate species from the French coast of the Eastern English Channel collected in June and November 2012. Total mercury concentrations in the muscle tissues ranged between 0.04 and 1.63 µg g-1(d.w.). Dab and sandeel displayed a significant positive correlation between Hg concentrations and fish length. Seasonal differences in Hg concentrations were observed for dab and shrimp. The lesser weever showed significantly higher concentrations of Hg (0.97 ± 0.34 µg g-1d. w.) than all other species. Gobies and sprat, which had the smallest size, showed significantly lower concentrations than herring, whiting, pout and sardine. Among the considered species, flatfish such as dab, flounder, plaice and sole displayed intermediate levels of Hg. In the present study, the fish age expressed as specimen length seems to be one of the major factors governing Hg contents in muscle tissues. Finally, mercury concentrations in commercial fish from the Eastern English Channel were below the levels fixed by the European Union for total mercury in edible parts of fish products. [ABSTRACT FROM AUTHOR]

Parasite of the genus Cryptocotyle are potential zoonotic trematodes present worldwide in many fish species. So far, its impact on human health is still unknown. Moreover, few publications deal with its recovery, identification and distribution among commercially important fish. Tool development was carried out for quantification of Cryptocotyle infection, isolation, including optimization of digestion, assessment of viability of metacercariae post mortem, and identification of parasite. Then, an epidemiological study was performed on seven commercial fish species: herring (Clupea harengus), sprat (Sprattus sprattus), whiting (Merlangius merlangus), pout (Trisopterus luscus), dab (Limanda limanda), flounder (Platichthys flesus) and plaice (Pleuronectes platessa). The samples were collected during the sea campaign of the International Bottom Trawl Survey in the Eastern English Channel and the North Sea in January 2019 and 2020. Cryptocotyle infection was estimated by counting black spots due to this parasite on the whole fish. Metacercariae were characterized by classical methods from a morphological point of view with microscopic observations and from a molecular perspective with Sanger sequencing of fragments of mtDNA cox1 gene and of rDNA ITS region. Morphological data were compared to available literature data. Phylogenetic trees including reference sequences were built to confirm morphological and molecular identifications. The prevalence, intensity and abundancy displayed differences between fish species and fishing areas. This survey constitutes the first description of C. lingua and C. concava metacercariae in the Eastern English Channel and North Sea ecosystems. [ABSTRACT FROM AUTHOR]

Understanding and modelling fleet dynamics and their response to spatial constraints is a prerequisite to anticipating the performance of marine ecosystem management plans. A major challenge for fisheries managers is to be able to anticipate how fishing effort is re-allocated following any permanent or seasonal closure of fishing grounds, given the competition for space with other active maritime sectors. In this study, a Random Utility Model (RUM) was applied to determine how fishing effort is allocated spatially and temporally by the French demersal mixed fleet fishing in the Eastern English Channel. The explanatory variables chosen were past effort i.e. experience or habit, previous catch to represent previous success, % of area occupied by spatial regulation, and by other competing maritime sectors. Results showed that fishers tended to adhere to past annual fishing practices, except the fleet targeting molluscs which exhibited within year behaviour influenced by seasonality. Furthermore, results indicated French and English scallop fishers share the same fishing grounds, and maritime traffic may impact on fishing decision. Finally, the model was validated by comparing predicted re-allocation of effort against observed effort, for which there was a close correlation. [ABSTRACT FROM AUTHOR]

The effects of the aggregate extraction intensity and the distance to extraction sites on the distribution of fishing effort were investigated for a broad selection of French and English demersal fleets operating in the Eastern English Channel. The most prominent result was that most fleets fishing near to aggregate extraction sites were not deterred by extraction activities. The fishing effort of dredgers and potters could be greater adjacent to marine aggregates sites than elsewhere, and also positively correlated to extraction intensity with a lag of 0–9 months. The distribution of fishing effort of French netters remained consistent over the study period. However, it is of note that the fishing effort of netters has increased substantially in the impacted area of the Dieppe site (where it is correlated to extraction intensity with a lag of 6 months), while slightly decreasing in the intermediate and reference areas. The attraction of fishing fleets is likely due to a local temporary concentration of their main target species. However, knowledge of their life-history characteristics and habitat preferences suggests that some of these species could be particularly vulnerable to aggregate extractions in the longer term. [ABSTRACT FROM AUTHOR]

On the French marine shelf, marine aggregates are currently dredged by trailing suction hopper dredgers (TSHD), without screening, with an overflow process, with or against currents. In the framework of the Groupement d'Intérêt Scientifique (GIS) Suivi des Impacts de l'Extraction de Granulats Marins (SIEGMA), the dynamics of the turbid plume formed by the overflow was studied at an experimental dredging site (0.6 km²), located in the Bay of Seine (eastern English Channel), a macrotidal environment where the seabed is composed of sandy gravel. An original field strategy based on Lagrangian monitoring, using the back-scattered signal of an Acoustic Doppler Current Profiler (ADCP), Laser In Situ Scattering and Transmissometry (LISST) measurements, water samples, and aerial photographs, has shown good results in describing suspended sediment concentration (SSC) dynamics from a turbid plume. The behaviour of suspended sediment has been studied, for the first time, to our knowledge, from their release at the dredger overflow to their deposition on the seabed. A fluid mixture, overflowed from the TSHD, with a mean concentration of 6 g L-1 of mineral and organic silty sands, induces the formation of a turbid plume at the rear of the TSHD, with an immediate dilution effect about 10-100 on SSC. Then, the SSC decreases through the process of lateral dispersion and sedimentation until the plume disappear in 2 hours. Evolution of the plume characteristics (SSC, particle size and nature, geometry) makes it possible to quantify the processes involved: dilution, advection, dispersion, and settling. The passive and dynamic behaviours of the plume are analysed. Extensions of deposits are calculated for spring tide conditions: 800 m for sand and 6.5 km for silt. This study has been conducted in macrotidal and specific dredging conditions (orientation of the dredging tracks against currents, dredger speed, loading capacity, overflow type), whose effects on plume dispersion have been quantified. Indicators relative to the effect of the plume on the water column (I/R) and to the plume duration (T125SSC) are proposed. [ABSTRACT FROM AUTHOR]

Abstract: Photosynthetic parameters, phytoplankton assemblages and physicochemical parameters were analysed in the Strait of Dover along an inshore–offshore transect between September 2008 and December 2009. The samples were collected weekly at 9 stations only at the surface or at both surface and depth. The photosynthetic activity was obtained by measuring Rapid Light Curves (RLC) using Pulse Amplitude Modulated (PAM) fluorometry. Temporal variability of the maximal light utilization efficiency (α), maximum electron transport rate (ETRm) and light saturation coefficient (E k) were greater than spatial variability (in horizontal and vertical dimensions) whereas temporal variability of the maximum quantum yield (F v/F m) was of the same order of magnitude as its spatial variability within the water column (in the vertical dimension). ETRm and α were positively correlated and the slope of the relation varied significantly between the different depths and seasons. The highest values of ETRm and α were obtained in summer (June) and late autumn – early winter (September–October & December) and the lowest in spring (March–April). The spatial variability of these parameters was greater vertically than horizontally. Differences between depths were particularly pronounced at the station nearest to the coast where photosynthetic response seems to be controlled by the light history of the cells. Seasonal variability in photosynthetic activity was mostly related to phytoplankton assemblages, light and temperature whereas the light history of the cells within the water column could be the most important factor in depth variability. [Copyright &y& Elsevier]

Abstract: Classifying marine habitats is a growing research field and is of increasing interest to spatial planners and managers. Most studies have predominantly focused on the seabed to determine benthic habitat types, and only limited attention has been paid to the water column. Classification projects aim at identifying candidate management units for the application of various regional or national regulations such as the European Water Framework Directive. Here, we propose a seasonal classification of the water column in the eastern English Channel, which we validated with biological data. For the three tested compartments, phytoplankton, zooplankton and pelagic fishes, the validation results were satisfactory, with recall values (i.e. percentage of observations correctly assigned in a given water type) ranging from 0.5 to 1. This validation was a crucial step to verify that the proposed typology was ecologically relevant and to use it as a biodiversity surrogate in management and conservation plans. Because management plans are generally set on an annual rather than a seasonal basis, we also produced a “multi-seasonal” typology encompassing seasonal variability, which can be used as an appropriate all year round description of the water column attributes in the eastern English Channel. The “multi-seasonal” typology reflected the relative stability of the French waters and the central part of the eastern English Channel and the strongest variability of the English coastal waters and the Dover strait. [Copyright &y& Elsevier]

Abstract: Previous research to assess impacts from aggregate dredging has focussed on infaunal species with few studies made of fish entrainment. Entrainment evidence from hydraulic dredging studies is reviewed to develop a sensitivity index for benthic fish. Environmental monitoring attendant with the granting of new licences in the Eastern Channel Region (ECR) in 2006 offers a unique opportunity to assess the effects of dredging upon fish. Projected theoretical fish entrainment rates are calculated based upon: abundance data from 4m beam trawl sampling of fish species over the period 2005–2008; sensitivity data; and dredging activity and footprint derived from Electronic monitoring System (EMS) data. Results have been compared with actual entrainment rates and also against summary results from independent analysis of the changes in fish population over the period 2005–2008 (). The case is made for entrainment surveys to form part of impact monitoring for marine aggregate dredging. [Copyright &y& Elsevier]

Abstract: Regional annual sampling of commercial fish stocks formed a high priority for monitoring studies attendant with the granting of aggregate dredging licenses in the Eastern Channel Region (ECR) which had previously not been dredged. An assessment of 4m beam trawl sampling between 2005 and 2008 following the granting of licences in 2006 is provided. The majority of fish species have shown marked reductions in abundance since commencement of dredging. Draghead entrainment has been identified as a possible contributory cause based upon the known vulnerability of selected species (). Other environmental factors considered offer no explanation for the changes in abundance. Comparative analyses with ICES data for plaice and sole over the study period demonstrate that changes in the ECR do not result from seasonal flux in the wider populations. An alternative impact model and potential mitigation measures are suggested. [Copyright &y& Elsevier]

Delavenne, J., Metcalfe, K., Smith, R. J., Vaz, S., Martin, C. S., Dupuis, L., Coppin, F., and Carpentier, A. 2012. Systematic conservation planning in the eastern English Channel: comparing the Marxan and Zonation decision-support tools. – ICES Journal of Marine Science, 69: 75–83.The systematic conservation approach is now commonly used for the design of efficient marine protected area (MPA) networks, and identifying these priority areas often involves using specific conservation-planning software. Several such software programmes have been developed in recent years, each differing in the underlying algorithms used. Here, an investigation is made into whether the choice of software influences the location of priority areas by comparing outputs from Marxan and Zonation, two widely used conservation-planning, decision-support tools. Using biological and socio-economic data from the eastern English Channel, outputs are compared and it is shown that the two software packages identified similar sets of priority areas, although the relatively wide distribution of habitat types and species considered offered much flexibility. Moreover, the similarity increased with increasing spatial constraint, especially when using real-world cost data, suggesting that the choice of cost metric has a greater influence on conservation-planning analyses than the choice of software. However, Marxan generally produced more efficient results and Zonation produced results with greater connectivity, so the most appropriate software package will depend on the overall goals of the MPA planning process. [ABSTRACT FROM PUBLISHER]

Macrobenthic assemblages were examined in three fish estuarine nurseries and related to environmental variables, as well as fish and macrocrustaceans, in order to assess and compare the potential foraging ground value of these systems. Macrobenthos was sampled in spring 2007 in the Canche, Authie and Somme estuaries (eastern English Channel, France). A total of 17, 28 and 23 macrobenthic taxa, with a clear dominance of amphipods (mainly Bathyporeia sarsi), polychaetes and bivalves, were recorded in the three estuaries respectively. Although predators (fish and macrocrustaceans) were abundant, relatively high densities of macrobenthos were observed: 876.2 ± 389.1, 595.4 ± 197.2 and 854.3 ± 281.2 ind. m-2 in the Canche, Authie and Somme, respectively. No significant difference in species richness, Shannon–Wiener diversity and density (total and dominant groups) of macrobenthos was observed between the three estuaries. Although the analysis of similarity and similarity percentages analyses indicated that macrobenthic assemblage was variable between Authie and Somme, results showed that macrobenthos resource was relatively high and similar in the three estuaries. Taking into account these considerations, the present study indicated a similar relative importance of the Canche, Authie and Somme estuaries as foraging grounds for fish and macrocrustaceans during spring. Multivariate analysis showed that macrobenthic assemblages were mainly driven by salinity and sediment characteristics in the Canche and Authie estuaries while in the Somme estuary sediment characteristics were the most influencing parameters. [ABSTRACT FROM PUBLISHER]

Abstract: A numerical approach based on the coupling of the wave propagation module SWAN (Simulating WAves Nearshore) with the three-dimensional circulation module COHERENS (COupled Hydrodynamical-Ecological model for RegioNal and Shelf seas) is developed to simulate the impact of a northerly wind-generated storm on the resuspensions of heterogeneous sediments in the Dover Strait and adjacent waters. Suspended sediment transport is computed for the four grain-size classes of silts , very fine sands , fine sands and medium sands . Predicted times histories of wave variables and the near-bottom mean current and total suspended sediment concentration (SSC) are compared with field data collected off Merlimont Beach, in the south of Boulogne-sur-Mer. Mappings of the growth of the near-bottom total SSC during the storm are produced. The total SSC increases by four at the Merlimont site. The multiplying factor reaches 40 along the exposed northern French coastline revealing the Flandres bed features. This increase is limited to five in deep waters of the southern Dover Strait with local strengthening on the top of the Vergoyer and the Bassure de Baas sandbanks. The storm modifies the granulometric composition of suspended materials by increasing the contribution of medium sands. Main modifications appear at the south-western entrance of the Dover Strait and in the exposed southern North Sea. The near-bottom resuspensions remain elsewhere dominated by the local resuspensions of fine sands added to remote resuspended silts advected by currents. [Copyright &y& Elsevier]

Lefebvre, A., Guiselin, N., Barbet, F., and Artigas, F. L. 2011. Long-term hydrological and phytoplankton monitoring (1992–2007) of three potentially eutrophic systems in the eastern English Channel and the Southern Bight of the North Sea. – ICES Journal of Marine Science, 68: 2029–2043.The spatial and main temporal variations in nutrient concentrations and phytoplankton abundance were investigated between 1992 and 2007 in the eastern English Channel and the Southern Bight of the North Sea, zones of consistent presence of Phaeocystis globosa and diatom blooms. Silicate and phosphate were the main nutrients potentially limiting phytoplankton growth, but the dynamics of the limitation seemingly differ between sites. Phosphate concentration showed a clear monotonic decreasing trend, whereas dissolved inorganic nitrogen and silicate trends were more complex. Nitrate was rarely or never a limiting factor. Results highlight three main periods with a Phaeocystis- or diatom-dominated system in the 1990s, and a more complex pattern in the 2000s. The composition of the phytoplanktonic community is described and an attempt made to establish a link between the community and its environment in terms of variability, shifts, and trends. The effects of larger- vs. regional-scale controlling factors are also discussed. [ABSTRACT FROM PUBLISHER]

The article discusses a study of the dynamics of soluble extracellular polymeric substances (S-EPS) and transparent exopolymer particle (TEP) pools in coastal ecosystems. In particular, time series of S-EPS and TEP fractions were studied in natural phytoplankton assemblages at the Bay des Veys and Lingreville-sur Mer, two macrotidal sites in the English Channel. The link between TEP production and phytoplankton and nutrient dynamics in spring and summer is suggested. Also noted is the impact of hydrodynamic forcings on TEP concentration variations in autumn and winter. It concludes that the origins of TEP and S-EPS are different as indicated by the different production patterns.

The community structures and succession of phytoplankton, protozooplankton and copepods were studied from February 2007 to July 2009 in a coastal area of the eastern English Channel subject to Phaeocystis globosa blooms. While diatom blooms preceded P. globosa blooms each year, the community structure and stock of heterotrophic protists appeared to be related to the dominant P. globosa life cycle stages. In 2007, the dominance of large colonies (>100 µm, up to 316 µg C L−1), which resulted in a high biomass of healthy free cells (up to 132 µg C L−1), accompanied high spirotrich ciliate stocks (up to 58 µg C L−1) and high abundances of the copepods Acartia clausi and Temora longicornis (up to 11 ind. L−1). In 2008, the bloom which lasted a shorter period of time was dominated by large colonies (up to 328 µg C L−1) and fewer free cells (up to 98 µg C L−1). This corresponded with a lower abundance of grazers, with stocks of heterotrophic protists and copepods 1.6 times and 2.2 times lower, respectively. In 2009, the P. globosa bloom was again dominated by large colonies and <100 µm diatoms. This corresponded to a dominance of heterotrophic dinoflagellates among the protists (62% of the total heterotrophic protist biomass) and Acartia clausi (55% of the copepod abundance). Overall, heterotrophic dinoflagellates appeared to be likely the most important group of phytoplankton grazers. [ABSTRACT FROM AUTHOR]

Abstract: The impacts of marine aggregate dredging and the recovery levels, 1 and 10 years after cessation of dredging, are investigated for a commercial dredging site. The site consists of mixed sandy to pebbly sediments. Dredging intensity is low (generally less than 1h/ha/year) and heterogeneous in space and time, allowing to distinguish adjacent areas of active extraction, fallow, recovery and overflow deposition. Surveys were conducted using a combination of acoustic (side-scan sonar), video and grab sampling techniques. Multivariate analysis has been utilized to define a seabed morphological and sedimentary zonation that provides a good habitat description and mapping. Sedimentary patchiness characterized by grain-size increased variability is identified as a feature indicative of seabed disturbance due to dredging activities. In the vicinity of the dredging areas, fine-sand content greater than 10% is indicative of overflow deposition resulting from dredging activities while coarse sand is found to be covering areas previously dredged but now recovered. Furrows created by dredging operations collapse within one year, and generally fully disappear within 10 years. They are usually covered by sands and bedforms, indicative of active sediment transport, are formed. This study confirms that a low dredging intensity strategy is recommended for mixed sediment areas under moderate hydrodynamic energy regimes as this of the study area. This allows natural recovery of the seabed to take place within a period of 10 years. [Copyright &y& Elsevier]