The coastal waters of the Maltese Islands, central Mediterranean Sea, sustain a diversity of marine habitats and support a wide range of human activities. The islands’ shallow waters are ...characterised by a paucity of hydrographic and marine geo-environmental data, which is problematic in view of the requirements of the Maltese Islands to assess the state of their coastal waters by 2012 as part of the EU Marine Strategy Directive. Multibeam echosounder (MBES) systems are today recognised as one of the most effective tools to map the seafloor, although the quantitative characterisation of MBES data for seafloor and habitat mapping is still an underdeveloped field. The purpose of this study is to outline a semi-automated, Geographic Information System-based methodology to map the distribution of habitats in shallow coastal waters using high-resolution MBES data. What distinguishes our methodology from those proposed in previous studies is the combination of a suite of geomorphometric and textural analytical techniques to map specific types of seafloor morphologies and compositions; the selection of the techniques is based on identifying which geophysical parameter would be influenced by the seabed type under consideration.
We tested our approach in a 28km2 area of Maltese coastal waters. Three data sets were collected from this study area: (i) MBES bathymetry and backscatter data; (ii) Remotely Operated Vehicle imagery and (iii) photographs and sediment samples from dive surveys. The seabed was classified into five elementary morphological zones and features – flat and sloping zones, crests, depressions and breaks of slope – using morphometric derivatives, the Bathymetric Position Index and geomorphometric mapping. Segmentation of the study area into seagrass-covered and unvegetated seafloor was based on roughness estimation. Further subdivision of these classes into the four predominant types of composition – medium sand, maërl associated with sand and gravel, seagrass settled on sand and gravel, and seagrass settled on bedrock – was carried out through supervised classifications of morphometric derivatives of the bathymetry and textural indices of backscatter, based on information from training stations. The resulting morphologic and seabed composition maps were combined to plot the distribution of the predominant habitats in the coastal waters offshore NE Malta, some of which are of high conservation value. Ground-truthing of the habitat map using ROV imagery and dive observations confirms that our approach produces a simplified and accurate representation of seafloor habitats while using all the information available within the MBES data sets.
► We outline a semi-automated method to map habitats in shallow coastal waters. ► The method is based on high resolution multibeam bathymetry and backscatter data. ► It combines morphometric and textural analyses to map morphology and composition. ► We use method to plot distribution of the predominant habitats offshore NE Malta. ► Ground-truthing with ROV and dive observations confirms validity of our approach.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In the Maltese Islands, insufficient attention has been paid to vermetid reefs, endemic Mediterranean bioconstructions widely distributed along the southern part of the basin. As a result, this is a ...largely-overlooked coastal ecosystem despite the multitude ofecosystem services it provides. The perennial urban development in the Maltese Islands calls for the adoption of urgent action to protect coastal habitats, in particular bioconstructions that increase biodiversity and contribute to mitigating the effects of climatechange. The objective of our study was to extensively document the presence and typology of the vermetid reef ecosystems alongthe coast of Malta and Gozo, assessing the occurrence of putative anthropogenic threats on the same ecosystem. Quantitative measurements were additionally taken to morphologically characterize the recorded bioconstructions. Furthermore, we tested thehuman pressure effect on the density of vermetid individuals and associated biodiversity. “True” trottoirs were only documentedalong the south-east coast of Malta, where unfortunately land reclamation projects are expected to be implemented. Although no direct relation between a number of assessed human activities and the density of vermetid individuals was reported in the current study, we suggest the conduction of further studies to investigate the influence of specific disturbances on the conservation status of this ecosystem. This study expands the existing knowledge on the status of vermetid reefs in the Maltese Islands and calls for management and conservation actions to preserve this bioconstruction.
Cumulative human impacts have led to the degradation of marine ecosystems and the decline of biodiversity in the European and contiguous seas. Effective conservation measures are urgently needed to ...reverse these trends. Conservation must entail societal choices, underpinned by human values and worldviews that differ between the countries bordering these seas. Social, economic and political heterogeneity adds to the challenge of balancing conservation with sustainable use of the seas. Comprehensive macro-regional coordination is needed to ensure effective conservation of marine ecosystems and biodiversity of this region. Under the European Union Horizon 2020 framework programme, the MarCons COST action aims to promote collaborative research to support marine management, conservation planning and policy development. This will be achieved by developing novel methods and tools to close knowledge gaps and advance marine conservation science. This action will provide support for the development of macro-regional and national policies through six key actions: to develop tools to analyse cumulative human impacts; to identify critical scientific and technical gaps in conservation efforts; to improve the resilience of the marine environment to global change and biological invasions; to develop frameworks for integrated conservation planning across terrestrial, freshwater, and marine environments; to coordinate marine conservation policy across national boundaries; and to identify effective governance approaches for marine protected area management. Achieving the objectives of these actions will facilitate the integration of marine conservation policy into macro-regional maritime spatial planning agendas for the European and contiguous seas, thereby offsetting the loss of biodiversity and ecosystem services in this region.
The impact of recreational fishing on fish stocks remains largely unknown, as this is inherently difficult to monitor, especially in areas such as the Mediterranean Sea where many species are ...targeted using a variety of fishing gears and techniques. This study attempts to complement existing data sets and construct the profile of recreational fisheries in the EU‐Mediterranean countries using videos publicly available on social media. A total of 1526 video records were selected, featuring the capture of 7799 fish specimens. The results show recreational fishing is multispecies in nature (26 species contributed to >80% % of the most numerically important species caught) and exhibits a spatially homogeneous pattern, with differences in species composition being mostly dependent on the fishing technique used rather than on the country. Such findings fill an important knowledge gap on recreational fishing activities, and the methodology provides an innovative approach to gather statistics on data‐poor thematic areas that can potentially complement other data sets, such as the EU Data Collection Multi‐Annual Programme.
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DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
We studied the relationships between sediment industrial pollutants concentrations, sediment characteristics and the dinoflagellate cyst abundance within a coastal lagoon by investigating a total of ...55 sampling stations within the Bizerte lagoon, a highly anthropized Mediterranean ecosystem. The sediment of Bizerte lagoon is characterized by a high dinocyst abundance, reaching a maximum value of 2742cysts·g−1 of dry sediment. The investigated cyst diversity was characterized by the presence of 22 dominant dinocyst morphotypes belonging to 11 genera. Two dinoflagellate species dominated the assemblage: Alexandrium pseudogonyaulax and Protoperidinium claudicans, representing 29 to 89% and 5 to 38% of the total cyst abundance, respectively, depending on the station. Seven morphotypes belonging to potentially toxic species were detected, including Alexandrium minutum, A. pseudogonyaulax, Alexandrium catenella/tamarense species complex, Lingulodinium polyedrum, Gonyaulax cf. spinifera complex, Prorocentrum micans and Protoceratium reticulatum. Pearson correlation values showed a positive correlation (α=0.05) between cyst abundance and both water content and fine silt sediment content. Clustering revealed that the highest abundance of cysts corresponds to stations presenting the higher amounts of heavy metals. The simultaneous autoregressive model (SAM) highlighted a significant correlation (α=0.05) between cyst accumulation and two main factors: sediment water content and sediment content for several heavy metals, including Hg, Cd, Cu, Ni and Cr. These results suggest that the degree of heavy metal pollution could influence cyst accumulation patterns.
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•Impact of industrial pollutant on cyst abundance and distribution•Statistical correlation between trace metal and cysts abundance•Importance of highlighting dinoflagellate cyst assemblage within Bizerte Lagoon•Levels of inorganic and organic contaminants within Bizerte lagoon
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Limestone rocky shores constitute ca 90.5% of the 272km coastline of the Maltese islands. Only some 40% of this rocky coastline is gently sloping and easily accessible. Such shores are heavily ...impacted with 96% of the accessible coastline dominated by tourist-related or by maritime activities. We characterised the biotic assemblages of lowland Maltese rocky shores and tested the popularly held view that given the scarce variation in physical characteristics, such shores form a homogenous habitat. Belt transects were laid perpendicular to the shoreline from biological zero to the adlittoral zone on seven Coralline Limestone and one Globigerina Limestone shores. Cover (for algae and encrusting species) or population density (for animals except sponges) were estimated using 0.5m X 0.05m quadrats placed contiguously for the first few metres and then at regularly spaced intervals. Overall, 19 faunal and 47 floral species, and 10 faunal and 8 floral species were recorded from the Coralline and Globigerina transects respectively, with 60.8% faunal and 25.6% floral species common to the two substrata. Hierarchical clustering showed that the Coralline and Globigerina transects harboured distinct biotic assemblages and identified an upper shore assemblage dominated by the littorinid Melarhaphe neritoides and barnacles, and a lower shore assemblage dominated by algae and molluscs; a mid-shore transition zone where certain species from both assemblages reached peaks of abundance was present in almost all Coralline and the majority of Globigerina transects. Differences in biota between the two types of shore are most likely primarily related to differences in microtopography and, to a lesser degree, to exposure. It is concluded that in spite of gross physical similarity, Maltese lowland rocky shores are biotically inhomogeneous, making conservation of individual sites much more important than previously thought.
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BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The potential of citizen science in monitoring transient biological phenomena occurring over large spatial scales, such as the blooming of jellyfish species, has received increased acknowledgment in ...recent years. The Spot the Jellyfish citizen science campaign was launched by the International Ocean Institute and by the University of Malta in the summer of 2010, with thousands of jellyfish spotting reports having been submitted by sea-users through the campaign website, social media site, smart phone app or even through email, since then. The 2011-2015 submitted jellyfish reports were analysed, besides a number of water quality parameters (temperature, salinity, chlorophyll a content, nutrient and phytoplankton concentration), whose values were gleaned for the marine area of interest through online satellite water quality data portals. The main aim of this exercise was to seek to identify possible relationships, through a variety of univariate and multivariate statistical techniques, between the distribution of submitted campaign jellyfish records and the same water quality parameters. Possible bias introduced in the report database through artefacts such as differences in bay frequentation were addressed through normalisation procedures. Spatial differences in the abundance of jellyfish reports submitted along different parts of the Maltese coastline emerged, with the highest number of such reports having been submitted along the north-eastern coastline of the island of Malta, and jellyfish sighting reports correlated well with the values of the selected water quality values. Despite this, our results indicate that besides the selected water quality parameters, other forces, possibly hydrodynamic ones, were contributing to the recorded spatial variability in jellyfish occurrence.
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BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
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