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The bottom communities of the nearshore zone of the Valaam archipelago (Lake Ladoga) have been investigated. The stations were located in the littoral, sublittoral, and profundal at depths of 1–25 m. Three regions with different characteristics of the coast shore and relief were researched. A sampler-syringe was used to collect benthos, because it works the whole of grounds variety in the nearshore. The quantative characteristics of the bottom communities had been optimally described with the depth ranges. The wave activity significantly affected only the numbers of zoobenthos in the upper 10 m. The openness of the bay had a greater influence on the abundance and biomass of benthos in the range of 1–10 m, presumably taking into account the influence of reflected waves. The biggest numbers and biomass of zoobenthos were in the littoral of the close bay. In the semiclose bay and on the open coast, the maximum abundance of benthic invertebrates shifted in the sublittoral (depth >8 m), where waves affected the benthic communities less. The types of ground significantly affected only the taxonomical composition. In general, the preferential effect on the quantity characteristics of benthos on the rocky slope zone had the features of a shore (openness and depth patterns). These data can be used for inspections of the next influences on the nearshore benthic community and for analyzing and modeling the commercial resources and their forage base. [ABSTRACT FROM AUTHOR]

About 80% of the seabed of the English Channel (EC) is covered by coarse sediment, from coarse sand to pebbles. Quantitative data on the benthic macrofauna in these types of sediment remains are rare due to the difficulty of using grab corers in such hard substrates. The deepest central part of the EC (45–101 m depth) was prospected during two VIDEOCHARM surveys in June 2010 and June 2011 to increase knowledge of such sublittoral coarse sediment benthic habitats. Sampling focussed on a longitudinal transect in the deepest part of the EC (13 boxes), extending from the western approach to the Greenwich meridian. Both indirect (side scan sonar, Remote Operated Vehicule) and direct (grab sampling with benthos determination, and grain-size analyses) approaches were used and combined, permitting description of the benthic habitats and communities using seven methods. Five benthic EUNIS habitats (European Nature Information System) were reported: MC3215, MD3211, MC4, MC3212 and MC4215, of which two extended main habitats (MC3211 and M23212) corresponded to an eastern/western gradient from sandy gravel to sandy gravel and pebbles sediment. Three other spatially discrete habitats were associated with poor coarse sand and gravel habitats as well as sandy gravel and pebbles with the presence of the brittle star Ophiothrix fragilis. Taxonomic richness of both extended habitats was on the same order of magnitude as the coarse sand habitat reported elsewhere in the EC, whilst the abundances were among the lowest in deeper areas with low nutrient input and low primary production. The epifauna appeared relatively homogenous in this type of sediment at the scale of the sampling area and was not determined to assign a EUNIS habitat/class. ROV footage illustrated the presence of large epifauna and provided valuable information to ground truth in other sampling methods such as side scan sonar mosaic. Grab photos showing surface sediment was relevant to determine the sediment type, whilst granulometric analyses gave additional information on fine particles content (typically very low). [ABSTRACT FROM AUTHOR]

The Lower Devonian interval in the northeastern Timan–Pechora petroliferous basin is composed of polygenic carbonate rocks. Various depositional environments governed the distribution of different type and quality reservoirs in these rocks. Sedimentation took place in vast tidal plains, shallow sublittoral zones, and carbonate shoals within them. The facies heterogeneity of carbonate rocks led to a different intensity of postsedimentary transformations reflected in the complex morphology of pore space and the consequent variable filtration-capacity characteristics of the Lower Devonian reservoir rocks governing the main productivity of the Lower Paleozoic Timan–Pechora petroliferous basin. [ABSTRACT FROM AUTHOR]

Abstract Soft-bottom macrobenthic invertebrates are sensitive to natural or anthropogenic changes in aquatic ecosystems. The distribution patterns of sublittoral macrobenthic species in Guanabara Bay were studied from 2005 to 2007. Samples were collected at ten stations during six surveys throughout the rainfall regime (dry, early and late rainy). Ten replicates were collected at each station by Gravity corer or skin diving. Van Dorn bottles (bottom water) and by Ekman sediment sampler (granulometry) provided material for abiotic data. Stations were grouped into sectors (Entrance, Intermediary and Inner) based on abiotic data and location. The Redundancy Analysis (RDA) and Parsimonious RDA for all years and each annual cycle showed indicator taxa with high dominance in each sector. PERMANOVA indicated a regular seasonality between the surveys for the first annual cycle (p 0.05), possibly due the low rainfall observed during this period. The mosaic of soft-bottom substrates infers structural variables, and patterns of temporal distribution were basically influenced by parameters those indicating pollution and the SACW (South Atlantic Central Water) intrusion, as well as ecological attributes among species, such as: predation, competition. The Ervilia concentrica and Cypridinidae could be used as indicators for anthropic and natural impacts in the Guanabara Bay for the Entrance sector, while Cyprideis salebrosa and Cyprideis sp. for the Intermediary sector and Heleobia australis for the Inner sector.

Testate amoebae are widely used as proxies in paleoecological reconstructions of lacustrine environments; however, our knowledge on their distribution along depth gradients are limited. This study investigates the distribution of benthic testate amoebae along a sampling depth gradient (0 to 57 m) and related environmental characteristics in Lake Valdayskoe, Russia. In total, 101 species belonging to twenty-one genera were identified. Four types of testate amoeba assemblages (littoral, sublittoral, bottom slope and profundal) were distinguished that corresponded well to the bottom zones of the lake. The results of redundancy analysis indicated that sampling depth, temperature, pH and bottom inclination significantly explained 40.2% of the total variance in the species composition. Temperature and sampling depth had the largest individual contributions of 19.2 and 7.4% (p < 0.001), respectively. The minimal values of species diversity were observed on the littoral and at the lower boundary of the thermocline. We estimated depth optima and ranges for the species with high occurrences and distinguish stenobathic and eurybathic species. These data might improve the interpretations of paleoecological records of subfossil testate amoeba assemblages in lacustrine surface sediments and serve as basis for the development of a transfer function for reconstruction of lake depths.

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About 80% of the seabed of the English Channel (EC) is covered by coarse sediment, from coarse sand to pebbles. Quantitative data on the benthic macrofauna in these types of sediment remains are rare due to the difficulty of using grab corers in such hard substrates. The deepest central part of the EC (45–101 m depth) was prospected during two VIDEOCHARM surveys in June 2010 and June 2011 to increase knowledge of such sublittoral coarse sediment benthic habitats. Sampling focussed on a longitudinal transect in the deepest part of the EC (13 boxes), extending from the western approach to the Greenwich meridian. Both indirect (side scan sonar, Remote Operated Vehicule) and direct (grab sampling with benthos determination, and grain-size analyses) approaches were used and combined, permitting description of the benthic habitats and communities using seven methods. Five benthic EUNIS habitats (European Nature Information System) were reported: MC3215, MD3211, MC4, MC3212 and MC4215, of which two extended main habitats (MC3211 and M23212) corresponded to an eastern/western gradient from sandy gravel to sandy gravel and pebbles sediment. Three other spatially discrete habitats were associated with poor coarse sand and gravel habitats as well as sandy gravel and pebbles with the presence of the brittle star Ophiothrix fragilis. Taxonomic richness of both extended habitats was on the same order of magnitude as the coarse sand habitat reported elsewhere in the EC, whilst the abundances were among the lowest in deeper areas with low nutrient input and low primary production. The epifauna appeared relatively homogenous in this type of sediment at the scale of the sampling area and was not determined to assign a EUNIS habitat/class. ROV footage illustrated the presence of large epifauna and provided valuable information to ground truth in other sampling methods such as side scan sonar mosaic. Grab photos showing surface sediment was relevant to determine the sediment type, whilst granulometric analyses gave additional information on fine particles content (typically very low).

Summary: This study investigated the abundance, biomass, species richness, species distribution and feeding types of free-living nematodes in Lake Constance, a deep, oligotrophic lake in Germany. Three water depth zones, the sublittoral (13-30 m water depth), profundal (31-99 m) and deep profundal (100-250 m), were distinguished and 16 sites from each water depth zone were sampled. A high nematode species richness was determined at all three zones, with 129 species in the sublittoral, 113 in the profundal and 92 in the deep profundal. In total, 171 nematode species were identified in this study. The dominant species (relative abundance > 5%) in all water depths were Ethmolaimus pratensis , Eumonhystera filiformis , E. longicaudatula , E. vulgaris and E. andrassyi , Hofmaenneria brachystoma , Ironus tenuicaudatus , Monhystera paludicola / stagnalis , Prismatolaimus intermedius and Tobrilus gracilis. High mean densities of 507-730 indiv. 10 cm−2 were found at each water depth, with a mean overall density of 627 indiv. 10 cm−2. The high abundance resulted in a high mean biomass (1.19 mg wet weight 10 cm−2; range 0.92-1.37 mg wet weight 10 cm−2) for nematodes in Lake Constance. Deposit feeders were the dominant feeding type at all water depth zones (51.7%), followed by epistrate feeders (17.6%), chewers-omnivores (15.9%) and chewers-predators (11.0%). Suction feeders accounted for <4% in the lake as a whole. The structure of the nematode communities in the three zones correlated with sediment texture (water content, clay content), as well as total sulphur and nutrient-related parameters (ATP, bacteria, algae, C:N ratio). [ABSTRACT FROM AUTHOR]

The main characteristics of the population of Dreissena polymor­pha (Pallas, 1771) in Lake Pleshcheyevo in 2014–2016 are dis- cussed, and two different sampling methods for D. polymorpha are compared. The lack of mass reproduction of D. polymorpha in 2015 is possibly related, among other causes, to climate change and alterations in the temperature regime of the lake. Dreissena is shown to be one of the main benthic suspension feeders in Lake Pleshcheyevo.

The European oyster (Ostrea edulis) is under significant threat across its natural distribution range and even functionally extinct in some regions, such as in the German North Sea. Due to its ecological significance in terms of biodiversity and other ecosystem services, the species, and the habitat it provides, are defined as highly endangered by the OSPAR Convention.Restoration measures are gaining momentum in Europe and conclusive recommendations for large‐scale biogenic reef restoration are relevant for example within the Marine Strategy Framework Directive and the Habitats Directive.This study examined whether present‐day environmental conditions of sublittoral offshore waters are ecologically suitable for the return of European oysters. Seed oysters (shell length ~2 mm) were deployed in cages in offshore field experiments in 10–26 m water depth.Survival, growth, and condition were investigated over the course of 2 years. Survival was high, even over winter. Growth was excellent, with oysters reaching a mean length of 55.0 ± 7.2 mm shell length and 19.2 ± 6.1 g wet weight after 2 years.The formation of firmly aggregated oysters was observed and confirms O. edulis as a reef‐building species.The overall condition of oysters in the field was excellent, identified by high condition indices and early reproductive activity.These findings are highly relevant for future restoration measures in the North Sea as they confirm that present‐day environmental conditions and small, hatchery‐produced seed oysters are suitable of supporting sustainable and successful restoration efforts even in sublittoral offshore waters. [ABSTRACT FROM AUTHOR]

The designation of marine protected areas (MPAs) requires the development of a monitoring design to assess the effectiveness of the closure in meeting its conservation objectives. Natural variability should be considered in the design, ideally determined using baseline information collected at the scale of the closure.Monitoring benthos informs on general ecosystem state. Benthic habitat maps are widely used as surrogates of benthos in marine spatial planning, and could potentially be used to inform monitoring by minimizing confounding habitat effects.Here, epibenthic diversity was assessed in the St. Anns Bank MPA in Atlantic Canada, the first assessment of benthic patterns at the scale of this closure. Epibenthic assemblages were determined using a photographic camera system along a single transect (~100–150 m in length) at 44 locations in 2013 and 2014 (with 10 or 11 images per location, providing a total of 438 images), prior to the designation of the MPA. Epibenthic patterns were correlated with a previously developed benthic habitat (benthoscape) map to determine the potential of using benthoscape classes as units for monitoring.Hierarchical agglomerative clustering of epibenthic assemblages and similarity profile analysis revealed five clusters of assemblages in the MPA (P < 0.01), each of which were associated with specific indicator taxa. Some clusters of assemblages correlated well with distinct benthoscape classes representing either hard/coarse (gravel) or soft sediment (sand and mud), whereas clusters associated with mixed sediment segregated spatially. The within‐cluster variability in assemblages between locations was lower overall than within the management zones, but differed between clusters.Similarities were detected with previous coarser‐scale assessments of epibenthic diversity in the St. Anns Bank MPA, but this study revealed a more complex benthic structure than previously thought. A monitoring design should thus consider this natural variability to reliably monitor change and aid in determining the effectiveness of the MPA. [ABSTRACT FROM AUTHOR]

Since the 1990s, most currently assessed Mediterranean nekto‐benthic stocks have been exploited above maximum sustainable yield and have declined. This study explores the co‐occurrence of essential fish habitats for the most important nekto‐benthic resources exploited by bottom‐trawl fisheries in the western Mediterranean and areas of importance for nekto‐benthic communities.Fishery‐independent data obtained from Mediterranean scientific bottom‐trawl surveys were used to identify persistent hotspots of recruitment for the most important nekto‐benthic species around the Iberian Peninsula and the Balearic Islands between 2002 and 2016, as an indicator of their essential fish habitats. Likewise, hotspots of nekto‐benthic community diversity and density were also determined, as an estimate of key areas for nekto‐benthic communities.Areas of overlap of persistent hotspots of recruitment and of community species richness and density were mainly found on the deep shelf and the upper slope (100–200 m and 200–500 m deep respectively).These overlapping areas could be of particular interest in the development of fishery management plans aiming to implement an ecosystem approach to fisheries. Protection, through temporary or permanent closures, of the overlapping areas identified would contribute to improving both the sustainable exploitation of the main target species of bottom‐trawl fisheries and the conservation of nekto‐benthic communities. [ABSTRACT FROM AUTHOR]

Burrowers such as thalassinideans remobilize sediment in benthic ecosystems, altering granulometry, enhancing organic matter cycling and oxygenation. We characterized the distribution of the mud shrimp Upogebia noronhensis and the associated macroinfauna along a depth and granulometric gradient in a shallow subtidal area in the southern Brazilian coast. Mud shrimp densities were estimated by burrow opening count using 0.25 m2 quadrats in three sediment zones: sand, sand-mud transition and mud. Macroinfaunal community descriptors and sediment granulometric characteristics were assessed. U. noronhensis average density varied from 0.6 to 145 individuals m−2 and was highest in the transition zone and lowest in the sand zone. Macrofauna in the sand zone was at least three times more abundant and 1.2 times richer, averaging 436.3 organisms and 39 species, while the transition and mud zones were more even in species distribution (species evenness > 0.7). The shrimp presence seems to be linked to a coarse sand content

Populations of marine bivalves are subject to large interannual fluctuations as a result of their sensitivity to unfavourable environmental conditions. These populations have a strong dependence on recruitment, which constitutes a risk to stock conservation and the sustainability of the commercially exploited species. Bivalve sanctuaries comprising no‐take areas can promote the restocking of large coastal areas as a result of the high fecundity and the potentially long‐distance larval dispersal of bivalves.The present study explores a novel spatio‐temporal approach to investigate suitable locations for bivalve sanctuaries, aimed at protecting and enhancing stocks along the Algarve coast in southern Portugal. In the context of small‐scale fisheries, bivalve dredging constitutes an important socio‐economic activity. Three bivalve species are targeted: the striped venus (Chamelea gallina), the donax clam (Donax trunculus), and the surf clam (Spisula solida).Data gathered from 36 bivalve fishing surveys conducted over three decades (1986–2015) were analysed using geostatistical methods, accounting for temporal and spatial autocorrelation to produce continuous prediction maps of species distribution for each survey. The approach taken permitted the use of all scattered historical data collected by different methods. The predictions were then used to summarize and illustrate the spatial distribution of species across time, in terms of average biomass, variability, and maximum potential biomass, and to delimit the areas as a function of the species persistence (recurrent, occasional, or rare). The temporal patterns through space were further investigated using empirical orthogonal function (EOF) analysis. The areas accounting for 80% of the species biomass were also estimated.Results of this set of analyses led to the proposal of locations for establishing bivalve sanctuaries, aimed at enhancing the stocks of commercial bivalve species in the long term. Such an innovative spatio‐temporal approach and management strategy is replicable in other fishing resources and geographic areas. [ABSTRACT FROM AUTHOR]

Flapper skates (Dipturus intermedius) were once widespread in European shelf waters but are currently classified as critically endangered by the International Union for Conservation of Nature due to historical overexploitation. Novel monitoring approaches are needed to assess the efficacy of management measures, such as dedicated marine protected areas, for the conservation of relict skate populations.Flapper skates possess distinctive dorsal spot patterns, which could potentially be used for individual recognition using photo‐identification (photo‐ID) approaches. This study assessed the potential of photo‐ID as a method for individual recognition of a relict population of skates within a dedicated marine protected area in western Scotland (UK), which has long been targeted by directed recreational angling. A collection of 486 photographs of 373 separate skate capture events from 2011 to 2016, taken with standard mobile phones and compact cameras, was studied using visual pairwise comparison methods to determine number of individuals and recapture rates.Results indicated that adult flapper skates were individually recognizable with a high degree of certainty through comparison of spot patterns, assuming appropriate lighting conditions. A total of 226 individuals were identified, of which 77 (34%) were recaptured at least once. The average recapture interval was 308 days (SE: 29.4 days), with the longest recapture interval to date being 4.4 years. Spot patterns among recaptured tagged or otherwise uniquely identifiable skates were found to remain stable over timescales of months to >1 year.Results indicate that photo‐ID, based on photographs sourced through citizen science approaches, can provide a low‐cost alternative means of monitoring flapper skate presence and distribution for the purposes of underpinning management decisions. [ABSTRACT FROM AUTHOR]

The Antarctic sublittoral is one of the most demanding habitat for polar bottom-dwelling organisms, as the disturbance of this zone is highly intense. Rapid changes in the marine environment, such as increases in atmosphere and surface water temperatures, can cause dramatic changes in biodiversity, especially in glacial fjords affected by heavy melt water inputs from the retreating glaciers. In such areas, rocks are often an important support for local diversity, providing habitats for a number of encrusting organisms. Thus, understanding the patterns of diversity of shallow rock encrusting fauna and factors controlling it are particularly important. The structure and diversity patterns of rock encrusting fauna were examined from four ecologically contrasting sites in the shallow sublittoral (6–20 m) of Admiralty Bay (King George Island). The results revealed a rich and abundant encrusting community with bryozoans and polychaetes outcompeting representatives of other fauna such as foraminifera and porifera. Spatial variability in species composition, as well as biological parameters, revealed the trend of encrusting assemblages declining towards the inner fjord areas - strongly affected by high sediment input (species richness: 13.3 ± 1.2, and abundance: 68,932.99 ± 11,915.98 individuals m −2  ± standard error). In contrast, at sites more open to the central basin, a peak of biological parameters was observed (24.8 ± 1.4 and 297,360.9 ± 30,314.72, respectively). We suggest that increased sedimentation was the major factor structuring the encrusting assemblages in Ezcurra Inlet, masking the influence of other parameters, such as food and light availability, which are important for the distribution of epifauna. Thus, if the increasing intensity of glacial processes will continue in the upcoming years, the diversity of the encrusting fauna in the shallow sublittoral could dramatically decrease. [ABSTRACT FROM AUTHOR]

Abstract: 1. Biogenic reefs formed by bivalves are biodiversity hot spots that provide important ecosystem services, but are globally endangered. In Strangford Lough (Northern Ireland) the use of mobile fishing gear (MFG) has caused extensive damage to reefs formed by the horse mussel (Modiolus modiolus L.), leading to declines in their extent and condition. 2. Captive breeding and translocation have been proposed as potential restorative strategies for the remaining reefs, and thus the reproductive biology of M. modiolus as the keystone species needs to be described prior to attempting large‐scale ecological restoration. 3. Physiological condition and gametogenesis were studied in two sympatric M. modiolus subpopulations using direct gonad assessment methods. The size‐ and age‐frequency structure of the whole metapopulation were described to establish present or past recruitment events. 4. Although gonad condition remained high in each year for the two subpopulations studied, significant losses were recorded in one subpopulation. These observations are consistent with autumn and winter spawning, but were not recorded in reefs thought to be more damaged by MFG. 5. Length‐ and age‐frequency histograms showed a distinct bimodal distribution in all remnant M. modiolus subpopulations, which were dominated by mussels over 50 years old. Little or no successful recruitment has occurred in some subpopulations, where low reproductive output caused by declines in broodstock numbers might be preventing natural recovery. 6. A combined approach of strict protection of the remaining larval sources and active restoration through stock supplementation is recommended to address recruitment limitations and increase connectivity between remnant subpopulations. [ABSTRACT FROM AUTHOR]

new marine arthrotardigrade, Ligiarctus alatus sp. nov. found in sediments of the Brazilian continental shelf (100–150 m depth) in the Southwestern Atlantic Ocean, is described in this study. This new species was recorded from sites located in the major oil extraction basins in Brazil (Campos and Potiguar basins). Within the subfamily Floractinae, the genus Ligiarctus characteristically presents primary clavae bent backwards, occupying the reduced lateral edges of the head. The new species is clearly distinguishable from L. eastwardi, the only known species of the genus, by the presence of internal distal notches on all claws, and six aliform cuticular expansions (frontal ala, two anterolateral alae, two posterolateral alae and caudal ala) with continuous digitiform procuticular supports (caesti). Ligiarctus eastwardi has only a caudal ala without caesti and internal notches are present on external claws only. The same pattern of cuticular expansions and caesti exhibited by the new species also occurs in the genus Florarctus, increasing the difficulty of defining the taxonomy of the subfamily Florarctinae, and forcing the emendment of the generic diagnosis of Ligiarctus. [ABSTRACT FROM AUTHOR]

Coastal areas commonly consist of an environment of intense economic uses and are thus exposed to conflicts between anthropogenic activities and biodiversity. While several approaches of nature protection have been applied to the terrestrial domain, aquatic biotopes frequently still lack a good ecological state as required by EU policies (WFD and MSFD). For numerous years, the underwater world has been considered as one sphere and was neglected in the development of distinctive concepts of conservation for its variety of biotopes. This paper’s objective is the enhancement of ecological connectivity within the study area through the design of benthic wildlife corridors and a consequent sublittoral biotope network. A step-by-step approach is presented for the optimization of ecological potential in heavily modified coastal water bodies, using Kiel Fjord (Western Baltic Sea) as a case study. The procedure for the development of wildlife corridors includes defining and mapping of existing biotope types, the identification of key species for each biotope type and delineating their mobility range, the reconstruction of near-natural / pre-industrial conditions and deriving the protection priorities by comparing past with current / modified conditions. By harmonizing these scientific insights with the local land use of human society, proposals for biotope restoration and improvements can be made. In Kiel Fjord, compensation measures, obligatory for human interventions, such as construction work in the marine environment in this case, have been implemented and present an opportunity to enhance the connectivity of biotopes, thus creating wildlife corridors for their inhabitants. The composition of benthic wildlife corridors, forming a sublittoral biotope network in accordance with the present anthropogenic uses, holds potential for implementation in comparably altered coastal water bodies and integration into national and international frameworks, in anticipation of its functionality. [ABSTRACT FROM AUTHOR]

To meet the Convention on Biological Diversity's Aichi Target 11 on marine biodiversity protection and Aichi Target 6 on sustainable fisheries by 2020, as well as the Sustainable Development Goal (SDG) 2 on food security and SDG 14 on oceans by 2030, there is an urgent need to rethink how best to reconcile nature conservation and sustainable development., This paper argues for effective governance to support processes that apply principles of sustainable development and an ecosystem approach to decide about economic activities at sea such as aquaculture. It describes opportunities, benefits and synergies between aquaculture and MPAs as a basis for wider debate. The scope is not a comprehensive analysis of aquaculture and MPAs, but rather to present examples of positive interactions between aquaculture activities and MPAs. The unintended negative consequences are also discussed to present balanced arguments., This work draws from four workshops held in 2015 and 2016 and used to collect information from about 100 experts representing various sectors and perspectives., It is recognized that aquaculture is an important activity in terms of sustainable development. It can play a role in providing food security, poverty alleviation and economic resilience, in particular for MPA local communities, and contribute to wild stock enhancement, as an alternative to overfishing and for providing services to the ecosystem., This study showed that there is a need from both aquaculture and MPA sides for clarity of objectives and willingness for open and extensive dialogue. The paper concludes by describing a number of tools and methods for supporting greater synergies between aquaculture and MPAs., The results from this work have already helped to build a common understanding between conservation and aquaculture and initiate a rapprochement for increasing synergies. [ABSTRACT FROM AUTHOR]

A new species of nephtyid polychaete habiting from the sublittoral to the continental slope (depth 14-500 m) of the Northwest Atlantic is described. The most significant characters of adults are: interramal parts of the preacicular lobes are wrapped around the acicular lobes; interramal parts of the neuropodial postacicular lobes and interramal parts of the postacicular rows of neurochaetae wrapped around the acicular and preacicular lobes; interramal parts of the postacicular rows of notochaetae wrapped around the acicular and preacicular lobes and covered by the bases of the notopodial cirri. Comparison with other species of the genus is provided. [ABSTRACT FROM AUTHOR]

Invasion by marine species, often considered a grave threat to marine ecosystems, occurs throughout the world as a consequence of many anthropogenic activities. In coastal Paraná, many factors including shipping, aquaculture and the use of artificial substrates provide suitable environments for the establishment and rapid spread of introduced marine species. To better understand this process, the encrusting community was studied on polyethylene plates (n = 120, 10 x 10 cm) that were placed seasonally at fixed locations on the inner continental shelf to detect non-native species. Of the 62 taxa found, 40 were identified to species, 14 of which were native, 9 introduced and 17 cryptogenic. We found a new introduction while most introduced species were previously reported at a nearby estuary with an international port. Possible complementary explanations for these detections are 1) estuaries influence ecological processes on the inner continental shelf, 2) the study area is near the route of cargo and other ships entering the port, 3) other local vectors, such as hulls of fishing and recreational boats, and artificial reefs link the estuary to the offshore areas. Thus, not only are estuaries invaded by exotic species, but also non-indigenous marine species may be present in the open sea where they are likely to colonize artificial substrates.

The sublittoral megabenthic assemblages of a northwestern Mediterranean coarse sandy beach exploited for the bivalve Callista chione were studied. The spatial and bathymetric variability of its distinctive faunal assemblages was characterised by quantitative sampling performed with a clam dredge. The taxa studied were Mollusca Bivalvia and Gastropoda, Crustacea Decapoda, Echinodermata and Pisces, which accounted for over 99% of the total biomass. Three well-differentiated species assemblages were identified: (1) assemblage MSS (Medium Sand Shallow) in medium sand (D50=0.37 mm) and shallow waters (mean depth =6.5 m), (2) assemblage CSS (Coarse Sand Shallow) in coarse sand (D50=0.62 mm) in shallow waters (mean depth =6.7 m), and (3) assemblage CSD (Coarse Sand Deep) in coarse sand (D50=0.64 mm) in deeper waters (mean depth =16.2 m). Assemblage MSS was characterised by the codominance of the bivalves Mactra stultorum and Acanthocardia tuberculata. C. chione was dominant in both density and biomass in assemblages CSS and CSD. The occurrence of the crab Thia scutellata also characterised assemblage CSS, whereas the occurrence of the sea urchin Echinocardium mediterraneum characterised assemblage CSD. A depth breaking point of around 10 m determined the discontinuity between assemblages CSS and CSD, which was related to the closure depth of the beaches in the study area. Species richness was highest in the coarse sand communities; however, Shannon-Wiener diversity and Pielou equitability indexes were higher in the shallow fine sand community.

Recent results of field studies on the exposed coast of Lithuania were used to model the area occupied by the red alga Furcellaria lumbricalis using the Natural Neighbor interpolation technique, while linear regression was applied to estimate the species' standing stock. The area covered by F. lumbricalis extended for 26 km along the coast between depths of 1 and 15 m. The maximum species cover in the study area ranged between 4 and 10 m depth, which is one of the widest in the Baltic Sea. The modelled area of F. lumbricalis covered 35 ± 11 km2 with a total biomass of 7554 ± 3813 t.

Long-term monitoring (1990 to 2004) at four stations (50 to 60 m depth) off Punta Coloso, Antofagasta, northern Chile, has allowed us to study temporal changes in the sublittoral macrobenthic polychaete infauna composition and abundance. The numerical contribution of the polychaete fraction to the total fauna was high (65 to 93%), whereas biomass was smaller and variable (20 to 85%). The number of invertebrate species collected per cruise was relatively low (40 to 90 species) and the number of polychaete species ranged from 18 to 37 per cruise (mean = 29.9), with a cumulative number of 56 polychaete species. The most abundant species collected included the small-sized Aricidea pigmentata Carrasco (26.5%), Magelona phyllisae Jones (22.7%), Paraprionospio pinnata (Ehlers) (13.5%), Tharyx longisetosa Hartmann-Schröder (12.1%), and Prionospio peruana Hartmann-Schröder (11.8%). Clear general patterns or tendencies are not seen in temporal variations of polychaete fauna nor when analyzing the seasons individually. P. pinnata was the only dominant species to show a general tendency in abundance fluctuations. Although the study period included two El Niño events (1991-1992 and 1997-1998), a clear dynamic was not seen in either abundance or dominant species. The analyzed data validate or corroborate high stability or persistence over time that has been suggested for polychaete fauna in the study area. Such stability or persistence exists in spite of high seasonal variability and interannual fluctuations in the region’s oceanographic conditions.

Molluscan diversity associated with sublittoral soft-bottoms was studied in Heraklion Bay as part of a long-term multidisciplinary research programme in the coastal environment of northern Crete (eastern Mediterranean). Quantitative benthic samples were collected in a pilot survey from a grid of 28 stations, followed by a seasonal sampling carried out over a seven- station transect located from 10 to 40 m depth. Univariate and multivariate analyses indicated the presence of a clear zonation along the depth gradient for the molluscan fauna and three main associations were identified in bathymetric zones parallel to the coastline. The structure of the local molluscan communities revealed the existence of an extended transition zone (ecotone) between a shallow sandy association and a deeper muddy one and a functional pattern, based on the feeding guilds, was evident along the environmental gradient. Application of graphical techniques, by using molluscan taxocoenosis, indicated a rather naturally disturbed habitat. Beta-diversity measures indicated different seasonal community adaptations to the prevailing environmental conditions. Results derived from this study revealed that beta-diversity may be a good descriptor for the assessment of the strength and breadth of sublittoral transition zones along environmental gradients.

Projections show that climate change will lead to structural change in Arctic ecosystems. Studies project the extinction of local species and intense species invasion to the Arctic Ocean. A lack of basic biological data about the Arctic shallow water fish community will make it hard to assess whether these communities will change or not. Baseline studies in combination with future reassessments are needed to establish a basic knowledge about the change of these communities. This study provides a quantitative first time description of the shallow water fish community of Kongsfjorden, Svalbard. The fish assemblage in the depth range from 3 to 12 m was determined with respect to abundance and species composition. Among a total sample size of 2804 specimens, the presence of 12 fish species and one family (Liparidae) was detected. Myoxocephalus scorpius (shorthorn sculpin) (74.9 %), Gadus morhua (Atlantic cod) (17.2 %), and Gymnocanthus tricuspis (Arctic staghorn sculpin) (3.8 %) were identified as the most abundant species across all sampling sites. A significant relationship between algal coverage and fish abundance was detected. Furthermore, we demonstrated a fjord inward increase in biodiversity along the south shore that might be correlated with a change in hydrographic regime. [ABSTRACT FROM AUTHOR]

The protocols available for sampling and monitoring shallow subtidal rhodolith beds (RBs) are inadequate for the deep Mediterranean analogues, and need calibration in order to attain comparable results., After reviewing the present knowledge of the specificities of Mediterranean RBs, and in the framework of the ongoing international effort for their conservation, a two-step approach is suggested for their definition, identification, delimitation, description, and monitoring., Regional mapping should be improved, and RBs should be identified and delimited as those areas of the sea floor with >10% cover of live rhodoliths over a minimum surface of 500 m2, on 1:10000 scale. More detailed scales (at least 1:1000) should be used for monitoring selected RBs, in order to detect significant changes through time., Beside location and areal extent, the description of RBs should include the occurrence of macroscopic sedimentary structures of the sea floor, thickness of live cover, mean percentage cover of live thalli and surface live/dead ratio, cover of dominant morphologies of rhodoliths (simplified on a ternary diagram), and volumetrically important calcareous algal species., For the purpose of assessment of the ecological status and the evaluation of human-induced impacts, quantitative data about community composition are required. The comparative assessment of ecological status and the identification of RBs of high conservation value for special protection should consider the natural geographic and seasonal/annual variability of RBs., Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

1. In the planning of marine protected areas for the conservation of coral reef systems, it is important to be able to distinguish between certain bioregions, i.e. regions with distinct species assemblages. This was done off western Halmahera (Moluccas, Indonesia), where three such bioregions were distinguished based on species inventories of 41 coral reef sites. 2. The relative value of species belonging to different trophic groups was examined with regard to their possible role as indicators for these three regions. The study focused on ascidians (Ascidiacea), macroalgae, mushroom corals (Fungiidae), and a selection of coral-associated gastropods (Epitoniidae and Coralliophilidae). 3. The best results for the detection of bioregions were obtained when datasets of all four trophic groups were pooled. When comparing the taxa and their indicator values, ascidians were the most suitable, followed by macroalgae, corals and gastropods with 98, 83, 71 and 66 % certainties, respectively. The occurrence of 17 species correlated strongly with the bioregions, which therefore were identified as potential indicator species consisting of 13 ascidians, three macroalgae, and one mushroom coral. These data suggest that ascidians have a significant value as indicators to evaluate bioregion boundaries. 4. Water quality measurements indicated that salinity and turbidity could be responsible for at least part of the differences between the species assemblages in the three bioregions. [ABSTRACT FROM AUTHOR]

Although kelp beds and barren grounds are conspicuous ecological systems in temperate coastal regions, little is known about how these systems develop throughout succession; neither their trajectories nor their putative seral stages are presently well documented or understood. Herein, we present the results of a field study in northern Chile aimed to investigate the succession development of macrobenthic communities dominated by kelp Lessonia trabeculata and by crustose coralline algae (barren ground). At both sublittoral habitats, ceramic plates were deployed and the process of colonisation was then followed for 14 months with the aim of describing and comparing the successional patterns of the benthic community. At both ecological systems, taxonomic richness, density and percentage of cover increased throughout time, although fewer species colonised the artificial substrate at the barren ground. Many species were common colonisers at both ecological systems; however, the structure diverged as different species were added to each colonising community. Our results suggest that the succession in kelp beds and barren grounds was habitat and community-specific following an early to advance sequence of development. [ABSTRACT FROM AUTHOR]

Natural populations of Mediterranean commercial sponges have declined substantially over recent decades., The present study explored the distribution of genetic diversity of the endangered bath sponge Spongia lamella along the western Mediterranean and the Portuguese coast., Seven microsatellite markers were used to genotype 231 individuals scattered over nine populations. Basic genetic descriptors and population genetic analyses based on FST test, analyses of the molecular variance (AMOVA), Bayesian clustering, dissimilarity analysis of principal components, and demographic analyses were performed., Genetic differentiation between populations was large and highly significant (global FST = 0.236, P < 0.001). AMOVA and Bayesian analyses showed genetic differentiation among the Atlantic, Balearic, and North Mediterranean areas (FCT = 0.129, P = 0.003)., Restricted gene flow owing to short-distance larval dispersal and hydrographical barriers may be playing an important role in genetic differentiation., Recent bottlenecks were also detected for most populations of this sponge., The high levels of inbreeding, sub-structuring, and modest levels of genetic diversity that characterized populations of S. lamella (mean value of genetic diversity 0.512), may compromise its long-term survival. Only one population, from the Gibraltar Strait, presented high levels of genetic diversity (Ceuta, genetic diversity = 0.657), indicating a hotspot of genetic diversity for this species with special relevance for its conservation., Disease outbreaks and overexploitation may be the most important causes of genetic diversity impoverishment of S. lamella., Future conservation guidelines should focus on preserving genetic diversity within genetically impoverished populations by limiting exploitation, and increasing population size. Transplanting specimens from areas with high values of genetic diversity to areas with low diversity values or to areas that have recently experienced demographic declines could reverse the local and global recession of this species., Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The first data are presented on the species diversity and community structure of deep-sea benthic heterotrophic flagellates in the Arctic (the Kara Sea). Thirty-three species and forms of heterotrophic flagellates were found, with kinetoplastids, stramenopiles, apusomonadids, and choanoflagellates being predominant. The species diversity of the studied region was characterized by a high beta-diversity and a low alphadiversity, which is indicative of a substantially higher potential species richness of flagellates in the Kara Sea. The total number of species of flagellates decreased with increasing depth (from 15 to 554 m); peculiar features of the species composition of deep-sea flagellates were not revealed. However, the flagellate communities within two different biotopes (the upper layer of the bottom sediments and the loose, flocculent layer on the surface of sediments together with near-bottom suspended matter) had similar taxonomic and trophic structures, but differed in the ratio of species with different feeding strategies. Attached or free-swimming flagellates were predominant in the loose surfacelayer, whereas rapidly gliding species that are able to actively search for and capture food predominated in the bottom sediments. [ABSTRACT FROM AUTHOR]

A new species of nephtyid polychaetes Nephtys sachalinensis sp. n. from the upper sublittoral zone (at a depth of 10-107 m) off Northeast Sakhalin, the Sea of Okhotsk, is described. Diagnostic characters of adults are: an everted pharynx with 20 bifid terminal and 2 median simple terminal papillae; single median dorsal and ventral pharyngeal subterminal papillae absent; proximal and median parts of the pharynx are covered with verrucae; branchiae begin from the fourth chaetiger; acicular lobes are distinctly bilobed from the anterior chaetigers almost to the end of the body; each acicular lobe (both in notoand neuropodia) has one rounded outgrowth on its interramal side; subulate notopodial cirri at the median and posterior chaetigers; neuropodial postacicular lobes are no more than two times longer than the acicular lobes. The new species is compared with its related species. [ABSTRACT FROM AUTHOR]

La mineuse de la tomate, Tuta absoluta (Lepidoptera, Gelechiidea) est un déprédateur signalé pour la première fois en Algérie en 2008. L'évaluation des dégâts causés par ce nouveau ravageur n'a pas été étudiée en Algérie. C'est la raison pour laquelle nous avons été amenés à effectuer ce travail pour déterminer les déprédations et les pertes en rendement provoquées par les larves de ce microlépidoptère. Quatre serres ont été choisies dans la wilaya de Chlef: deux dans le littoral à Ténès et deux autres dans le sub-littoral à Zeboudja. Les résultats montrent que l'infestation par piégeage des mâles, capturés à la phéromone sexuelle, augmente progressivement au cours des mois et atteint une moyenne maximale de 1680 ± 336 par serre au mois de juin. Parallèlement, l'infestation des feuilles de tomate augmente également et enregistre au mois de juin un taux de 96 ± 0,08 % à Ténès et 57 ± 1,41% à Zeboudja. L'agressivité de la mineuse de tomate exprimée en nombre de mines par feuille varie dans le temps et dans l'espace. Durant la période de février à juin, le nombre de mines par feuille est plus important dans le littoral que dans le sublittoral et varie respectivement de 2 à 18 et de 1 à 12. L'étude de la voracité des larves exprimée par leurs poids corporels, correspondant à leurs stades, montre qu'il n'y a pas de différence significative de poids larvaire du même stade (P>0,05) alors que la différence de poids est significative entre les quatre stades larvaires (P<0,05). Le poids des feuilles consommées par larve durant les deux premiers stades larvaires L1 (4,22 ± 0,19 mg/L) et L2 (19,47 ± 0,08 mg/L) est très faible par rapport aux derniers stades L3 (75,88 ± 0,67 mg/L) et L4 (135,7 ± 0,78 mg/L). L'évolution des stades larvaires exige donc une augmentation du poids des feuilles consommées lequel se quatriple entre L1, L2 et L3. Le poids des feuilles consommées est significativement différent entre les quatre stades larvaires (P<0,05). La surface foliaire consommée par larve est quintuplée entre L1 et L2 puis sera multipliée par 2,5 pour L3 et L4. La différence de poids entre les fruits de tomate attaquées et non attaqués est très significative (P = 0,004). Le calibre des fruits de tomate cultivée dans le littoral est significativement plus petit que celui du sublittoral probablement à cause des grandes attaques de Tuta absoluta. Ainsi, les pertes moyennes en rendement par serre sont respectivement de 9,28 % à Ténès et 4, 17% à Zeboudja. [ABSTRACT FROM AUTHOR]

In June 2009, macrophytobenthos communities were studied by the method of sample plots in some areas of Amursky Bay (the cove south of the Krasnyi Cape) and Ussuriysky Bay (the bay south of the Zelyonyi Cape, Sobol' Bay, and at the southern extremity of Engelm Island) in the Sea of Japan. In total, 12 phytocenoses were found. Three phytocenoses, Zostera marina + Sargassum pallidum, Punctaria plantaginea, and Costaria costata + Desmarestia ligulata were identified in the water area near the Zelyonyi Cape. In the Sobol' Bay, four phytocenoses were formed, Phyllospadix iwatensis, Sargassum pallidum + Costaria costata, Polysiphonia morrowii + Palmaria stenogona, and Desmarestia viridis + P. morrowii. Three phytocenoses were observed at the southern coast of Engelm Island, Chordaria flagelliformis + Neorhodomela larix, Desmarestia viridis, and Costaria costata. Two phytocenoses were described in the bay south of Krasnyi Cape, viz., Zostera marina + Sargassum miyabei and Saccharina cichorioides. Detailed descriptions of phytocenoses and data on the biomass of dominant and minor species are reported. The data on the composition of communities of macrophytes can be used in monitoring programs of coastal marine ecosystems of the Peter the Great Bay. [ABSTRACT FROM AUTHOR]

A new species of marine interstitial wormshrimp, Ingolfiella maldivensis, is described from coral sand on the inner and outer reef off Magoodhoo island, Faafu atoll, Maldives. Six females were found and compared to other species from the Maldives and those bordering the Indian Ocean and beyond. Morphological resemblance ties it to a species from the Caribbean island of Curaçao. Both species are found in shallow sublittoral interstitial spaces. [ABSTRACT FROM AUTHOR]

Two species of Enhydrosoma Boeck, 1873, found in muddy sediments in the sublittoral zone of Gwangyang Bay, represent the first record of this genus in Korea. Enhydrosoma coreana, new species, shares a number of rare morphological features with the type species, E. curticauda Boeck, 1872, such as a bifid rostrum with centrally inserted sensilla, endopodal lobe of P5 with a peduncle, and a characteristic shape of the female genital field. They differ in the armature formula of the mandible, P1 endopod, and P5 exopod, size of the P5 peduncle, and minor details in the ornamentation of several somites. Enhydrosoma intermedia Chislenko, 1978 is redescribed from its holotype, freshly collected Korean material, and freshly collected material from and near its type locality in the Russian Far East. Its male is described for the first time. Minor morphological differences are observed between these two disjunct populations, such as longer caudal rami and sparse hair-like spinules on somites in Korean specimens. However, molecular data from the mtCOI gene suggest them to be conspecific. Detailed morphological comparisons between E. coreana and E. intermedia reveal a number of important differences, and molecular phylogenies suggest only a remote relationship. Their average pairwise maximum likelihood distances are very similar to those between other well-established genera of harpacticoid copepods. Geehyndrosoma, new genus, is erected to accommodate E. intermedia, together with E. brevipodum Gómez, 2004, from the Pacific coast of Mexico. [ABSTRACT FROM AUTHOR]

In this study, biodiversity patterns of free-living marine nematode communities were assessed in the Yangtze River estuary and its adjacent waters by certain diversity measures. The studied area exhibited spatial variation in nematode biodiversity patterns. According to habitat heterogeneity, two station groups, shallow water near shore area and shallow water continental shelf area, were observed in the Yangtze River estuary and its adjacent waters. In general, nematode abundance and species diversity in the near shore area were significantly lower than the continental shelf area. Salinity, sediment Chlorophyll-a (Chl-a) and Phaeophytin-a (Phaeo-a) concentrations were responsible for the discrimination of species diversity measures. They reflect the reverin influence to nematode species diversity. By contrast, our results showed that the average taxonomic distinctness with presence/absence data (Δ+), and the variation in taxonomic distinctness (Λ+) were not influenced by natural environmental variability, nor pollutant and anthropogenic disturbances. The funnel plots for Δ+ and Λ+ also indicate none of the studied stations were subjected to environmental stress and perturbation. Possibly because of nematodes' strong resistance to environmental stress, the taxonomic indices did not discriminate perturbed from unperturbed conditions in the present study. We should be cautious to regard the taxonomic distinctness indices as surrogates for other traditional indices such as the number of species or Shannon diversity. [ABSTRACT FROM AUTHOR]

Bryozoans are among the most important groups of the Southern Ocean benthic macrofauna, both in terms of species richness and abundance. However, there is a considerable lack of ecological research focused on their distribution patterns and species richness on smaller scale, especially in the soft bottom habitats of Antarctic glacial fjords. The aim of this study was to describe those patterns in the Admiralty Bay. Forty-nine Van Veen grab samples were collected at the depth range from 15 to 265 m, in the summer season of 1979/1980, at three sites distributed along the main axis of the fjord. Among 53 identified species of bryozoans, 32 were recorded in the Admiralty Bay for the first time. The most common and abundant species were Himantozoum antarcticum, Inversiula nutrix and Nematoflustra flagellata. Genera such as Arachnopusia, Cellarinella and Osthimosia were the most speciose taxa. It was demonstrated that depth was important for the distribution of the bryozoans. More than half of the recorded species were found only below 70 m. An influence of glacial disturbance was reflected in the dominance structure of colony growth-forms. The inner region of the fjord was dominated almost entirely by encrusting species, while the diversity of bryozoan growth-forms in less disturbed areas was much higher. In those sites the highest percentage of branched, tuft like species represented by buguliform and flustriform zoaria was observed. [ABSTRACT FROM AUTHOR]

Abstract: Although the use of coastal defence structures is expected to increase, little is known about the ecological impact of such structures on the natural environment. In particular, the temporal and spatial patterns of communities in association with artificial substrate are still poorly understood. This study examined possible effects of experimental tetrapod fields on the decapod crustacean community in a subtidal hard-bottom area in the southern North Sea. We performed in situ studies in the fields and along transects oriented away from the tetrapod fields. Species composition and abundances were assessed before and after the introduction of the artificial material. The study revealed a significant decrease of smaller, less vagile species (Pisidia longicornis, Pilumnus hirtellus, Galathea squamifera) over the entire study area in the years following the tetrapod introduction. For 2 species, Hyas araneus and Homarus gammarus, the tetrapods appeared to be highly attractive as habitat and shelter because their abundance increased over time. No distinct spatial or temporal effects were observed for mobile predatory crabs, such as Cancer pagurus and Liocarcinus spp. The results of the study demonstrate that possible effects of artificial structures on macro-invertebrates in temperate hard-bottom areas are highly species-specific and depend on the size, lifestyle and ecological requirements of the species. This work highlights the importance of long-term studies. Our findings clearly indicate that more time is needed to distinguish between natural and anthropogenic influences on species distributions. [Copyright &y& Elsevier]

A new species of Lepidodasys is described from sublittoral sandy sediments off the Atlantic coast of Florida. Lepidodasys ligni sp. n. is a small species (⩽ 450 μm) with a crossed-helical pattern of small, non-keeled, non-imbricated scales on the dorsal and lateral body surfaces, two columns of ventral, interciliary scales that form a herringbone pattern, and a series of anterior, lateral, dorsal and posterior adhesive tubes. Similar to L. castoroides from the Faroe Islands, the new species possesses a caudal constriction that demarcates the posterior end containing the caudal organ. The frontal organ lies within the posterior constriction, which is heavily invested with somatic circular muscles. These muscles are also present throughout the trunk and represent a novel condition for species of Lepidodasys, which were previously considered to lack somatic circular muscles. Posterior of the caudal constriction is a large, barrel-shaped caudal organ that is wrapped in a series of interdigitating, spindle-shaped, incomplete circular muscle fibers. The caudal organ contains a sclerotized central canal, but the absence of distal cuticular endpieces distinguishes the new species from its morphologically similar congener, L. castoroides. [ABSTRACT FROM AUTHOR]

The micro-scale spatial distribution patterns of a demersal fish and decapod crustacean assemblage were assessed in a hard-bottom kelp environment in the southern North Sea. Using quadrats along line transects, we assessed the in situ fish and crustacean abundance in relation to substratum types (rock, cobbles and large pebbles) and the density of algae. Six fish and four crustacean species were abundant, with Ctenolabrus rupestris clearly dominating the fish community and Galathea squamifera dominating the crustacean community. Differences in the substratum types had an even stronger effect on the micro-scale distribution than the density of the dominating algae species. Kelp had a negative effect on the fish abundances, with significantly lower average densities in kelp beds compared with adjacent open areas. Averaged over all of the substrata, the most attractive substratum for the fish was large pebbles . In contrast, crustaceans did not show a specific substratum affinity. The results clearly indicate that, similar to other complex systems, significant micro-scale species-habitat associations occur in northern hard-bottom environments. However, because of the frequently harsh environmental conditions, these habitats are mainly sampled from ships with sampling gear, and the resulting data cannot be used to resolve small-scale species-habitat associations. A detailed substratum classification and community assessment, often only possible using SCUBA diving, is therefore important to reach a better understanding of the functional relationships between species and their environment in northern temperate waters, knowledge that is very important with respect to the increasing environmental pressure caused by global climate change. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine whether a thermocline may constitute a barrier discouraging vertical migration of water mites. The research was carried out in May, June, July, and August 1999 in Lake Lubie, and a total of 3252 water mites (1880 females and 1178 males) belonging to 29 species were collected. A strong negative correlation was observed between the drop in temperature in the thermocline and the abundance and number of water mite species living beneath the thermocline. The negative correlation resulted from a considerable limitation of vertical migration of water mites by factors such as: low temperature below the thermocline, large difference between temperatures above and below the thermocline, and considerable thickness of the thermocline. During summer season, lower layers of the lake were increasingly penetrated by water mites as the temperatures above and below the thermocline were becoming more uniform. Lake species displayed the greatest ability to penetrate lower water layers and were present below the thermocline during the whole study period; moreover, their numbers were quite steady. On the contrary, the species, which are characteristic for small water bodies, crossed the thermocline in comparatively large numbers in June when the thermocline was of the lowest thickness. [ABSTRACT FROM AUTHOR]