Horizon scanning of potential threats to high-Arctic biodiversity, human health and the economy from marine invasive alien species: A Svalbard case study.

The high Arctic is considered a pristine environment compared with many other regions in the northern hemisphere. It is becoming increasingly vulnerable to invasion by invasive alien species (IAS), however, as climate change leads to rapid loss of sea ice, changes in ocean temperature and salinity, and enhanced human activities. These changes are likely to increase the incidence of arrival and the potential for establishment of IAS in the region. To predict the impact of IAS, a group of experts in taxonomy, invasion biology and Arctic ecology carried out a horizon scanning exercise using the Svalbard archipelago as a case study, to identify the species that present the highest risk to biodiversity, human health and the economy within the next 10 years. A total of 114 species, currently absent from Svalbard, recorded once and/or identified only from environmental DNA samples, were initially identified as relevant for review. Seven species were found to present a high invasion risk and to potentially cause a significant negative impact on biodiversity and five species had the potential to have an economic impact on Svalbard. Decapod crabs, ascidians and barnacles dominated the list of highest risk marine IAS. Potential pathways of invasion were also researched, the most common were found associated with vessel traffic. We recommend (i) use of this approach as a key tool within the application of biosecurity measures in the wider high Arctic, (ii) the addition of this tool to early warning systems for strengthening existing surveillance measures; and (iii) that this approach is used to identify high-risk terrestrial and freshwater IAS to understand the overall threat facing the high Arctic. Without the application of biosecurity measures, including horizon scanning, there is a greater risk that marine IAS invasions will increase, leading to unforeseen changes in the environment and economy of the high Arctic.

Hurdles and opportunities in implementing marine biosecurity systems in data-poor regions.

Managing marine nonindigenous species (mNIS) is challenging, because marine environments are highly connected, allowing the dispersal of species across large spatial scales, including geopolitical borders. Cross-border inconsistencies in biosecurity management can promote the spread of mNIS across geopolitical borders, and incursions often go unnoticed or unreported. Collaborative surveillance programs can enhance the early detection of mNIS, when response may still be possible, and can foster capacity building around a common threat. Regional or international databases curated for mNIS can inform local monitoring programs and can foster real-time information exchange on mNIS of concern. When combined, local species reference libraries, publicly available mNIS databases, and predictive modeling can facilitate the development of biosecurity programs in regions lacking baseline data. Biosecurity programs should be practical, feasible, cost-effective, mainly focused on prevention and early detection, and be built on the collaboration and coordination of government, nongovernment organizations, stakeholders, and local citizens for a rapid response.

Classification of non-indigenous species based on their impacts: considerations for application in marine management.

Assessment of the ecological and economic/societal impacts of the introduction of non-indigenous species (NIS) is one of the primary focus areas of bioinvasion science in terrestrial and aquatic environments, and is considered essential to management. A classification system of NIS, based on the magnitude of their environmental impacts, was recently proposed to assist management. Here, we consider the potential application of this classification scheme to the marine environment, and offer a complementary framework focussing on value sets in order to explicitly address marine management concerns. Since existing data on marine NIS impacts are scarce and successful marine removals are rare, we propose that management of marine NIS adopt a precautionary approach, which not only would emphasise preventing new incursions through pre-border and at-border controls but also should influence the categorisation of impacts. The study of marine invasion impacts requires urgent attention and significant investment, since we lack the luxury of waiting for the knowledge base to be acquired before the window of opportunity closes for feasible management.

Testing the potential for predictive modeling and mapping and extending its use as a tool for evaluating management scenarios and economic valuation in the Baltic Sea (PREHAB).

We evaluated performance of species distribution models for predictive mapping, and how models can be used to integrate human pressures into ecological and economic assessments. A selection of 77 biological variables (species, groups of species, and measures of biodiversity) across the Baltic Sea were modeled. Differences among methods, areas, predictor, and response variables were evaluated. Several methods successfully predicted abundance and occurrence of vegetation, invertebrates, fish, and functional aspects of biodiversity. Depth and substrate were among the most important predictors. Models incorporating water clarity were used to predict increasing cover of the brown alga bladderwrack Fucus vesiculosus and increasing reproduction area of perch Perca fluviatilis, but decreasing reproduction areas for pikeperch Sander lucioperca following successful implementation of the Baltic Sea Action Plan. Despite variability in estimated non-market benefits among countries, such changes were highly valued by citizens in the three Baltic countries investigated. We conclude that predictive models are powerful and useful tools for science-based management of the Baltic Sea.

Mussels (Mytilus spp.) in Svalbard contain microplastic particles in tissues: Implications for monitoring.

We examined the presence of microplastics in blue mussels Mytilus spp. from the intertidal zone of western Spitsbergen in Arctic Svalbard. The optical microscopy technique detected a total of 148 microplastics, with the highest concentration per mussel being 24 particles. Microplastics were found in 84% of the examined mussels. The microplastics ranged in size from <0.5 mm to 5 mm and consisted of fibers (83%), fragments (13%), plates (3%), and spherules (1%). The micro-Raman spectroscopy technique revealed four different types of polymers: polyethylene (67%), nylon-12 (17%), low-density polyethylene (11%), and polypropylene (5%). Our research shows that Arctic coastal waters are polluted with microplastics notwithstanding their remoteness. These findings suggest that microplastic contamination may harm marine life and coastal ecosystems and require further research into long-term environmental effects. We also indicate that intertidal mussels may be beneficial for monitoring microplastics because they can be collected without involving diving.

Marine ecosystem health and biological pollution: Reconsidering the paradigm.

Our study re-evaluates a fundamental paradigm in marine invasion ecology - whether introduced species are considered as contaminants, i.e. just present in the system, or whether they are pollutants per se, i.e. they cause biological harm. This re-evaluation includes the concepts of marine ecosystem health and biological pollution using the European Marine Strategy Framework Directive (MSFD) as an example. Hence, we clarify the distinction between "biological contamination" (pertaining to Non-Indigenous Species (NIS) introductions) and "biological pollution" (associated with Invasive Alien Species - IAS). We emphasize the need for comprehensive indicators that consider their ecological, economic, and societal impacts. The MSFD Descriptor D2 NIS is analysed using the "biocontamination-biopollution" gradient to better reflect the complexities of ecosystem health. We discuss limitations in current monitoring and evaluation criteria, such as the absence of unified NIS/IAS monitoring, challenges in interpreting ecological impacts, and context-dependent assessment results. We emphasize the importance of context-specific management measures, considering the origin of pressures, whether endogenic (caused within a management area such a regional sea) or exogenic (with causes from outside a management area). Ultimately, we underscore the importance of a holistic and adaptable approach to address the diverse challenges posed by biocontamination and biopollution, protecting both marine ecosystems and human well-being in an ever-changing environment.

Wave fetch and distance from the ocean determine the distribution of macroplastics in the intertidal zone of central Spitsbergen, Arctic.

In this study, we estimated the variety and distribution of macroplastics in the central part of Spitsbergen, Svalbard archipelago, Arctic. All marine litter photos were georeferenced, then identified using the OSPAR (2010) classification guide. The majority (90% of all objects) of marine debris was macroplastic with average number in the study area being 2.0 ± 0.4 objects per 100 m. It was determined that the full variety of macroplastic categories in the study area can be found after surveying approx. 8 km of coastline. Correlation analysis showed that the amount of macroplastic accumulated on the beaches decreases with distance from the open ocean and increases with wave fetch. When zoning the entire study area on the basis of a cluster analysis of the distribution of macroplastics, it was found that the geographical proximity of the sections is less important than the wave fetch.

A multi-criteria decision analysis model for ship biofouling management in the Baltic Sea.

Biofouling of ship hulls form a vector for the introduction of non-indigenous organisms worldwide. Through increasing friction, the organisms attached to ships' hulls increase the fuel consumption, leading to both higher fuel costs and air emissions. At the same time, ship biofouling management causes both ecological risks and monetary costs. All these aspects should be considered case-specifically in the search of sustainable management strategies. Applying Bayesian networks, we developed a multi-criteria decision analysis model to compare biofouling management strategies in the Baltic Sea, given the characteristics of a ship, its operating profile and operational environment, considering the comprehensive environmental impact and the monetary costs. The model is demonstrated for three scenarios (SC1-3) and sub-scenarios (A-C), comparing the alternative biofouling management strategies in relation to NIS (non-indigenous species) introduction risk, eco-toxicological risk due to biocidal coating, carbon dioxide emissions and costs related to fuel consumption, in-water cleaning and hull coating. The scenarios demonstrate that by the careful consideration of the hull fouling management strategy, both money and environment can be saved. We suggest biocidal-free coating with a regular in-water cleaning using a capture system is generally the lowest-risk option. The best biocidal-free coating type and the optimal in-water cleaning interval should be evaluated case-specifically, though. In some cases, however, biocidal coating remains a justifiable option.

A fully-annotated imagery dataset of sublittoral benthic species in Svalbard, Arctic.

Underwater imagery is widely used for a variety of applications in marine biology and environmental sciences, such as classification and mapping of seabed habitats, marine environment monitoring and impact assessment, biogeographic reconstructions in the context of climate change, etc. This approach is relatively simple and cost-effective, allowing the rapid collection of large amounts of data. However, due to the laborious and time-consuming manual analysis procedure, only a small part of the information stored in the archives of underwater images is retrieved. Emerging novel deep learning methods open up the opportunity for more effective, accurate and rapid analysis of seabed images than ever before. We present annotated images of the bottom macrofauna obtained from underwater video recorded in Spitsbergen island's European Arctic waters, Svalbard Archipelago. Our videos were filmed in both the photic and aphotic zones of polar waters, often influenced by melting glaciers. We used artificial lighting and shot close to the seabed (<1 m) to preserve natural colours and avoid the distorting effect of muddy water. The underwater video footage was captured using a remotely operated vehicle (ROV) and a drop-down camera. The footage was converted to 2D mosaic images of the seabed. 2D mosaics were manually annotated by several experts using the Labelbox tool and co-annotations were refined using the SurveyJS platform. A set of carefully annotated underwater images associated with the original videos can be used by marine biologists as a biological atlas, as well as practitioners in the fields of machine vision, pattern recognition, and deep learning as training materials for the development of various tools for automatic analysis of underwater imagery.

A comparison of impact and risk assessment methods based on the IMO Guidelines and EU invasive alien species risk assessment frameworks.

A comparative analysis of two risk assessment (RA) frameworks developed to support the implementation of the international Ballast Water Management Convention (BWMC) and European Regulation on Invasive Alien Species (IAS) was performed. This analysis revealed both differences and similarities between the IMO Risk Assessment Guidelines (IMO, 2007) and EU Regulation supplement on RA of IAS (EU, 2018) in RA approaches, key principles, RA components and categories of IAS impacts recommended for assessment. The results of this analysis were used to produce a common procedure for the evaluation of the bioinvasion risk and impact assessment methods intended to support international, regional and/or national policy on IAS. The procedure includes a scoring scheme to assess compliance with the key principles, RA components and categories of bioinvasion impacts taken into account by the methods. In these methods the categories of impacts on human health and economy are underrepresented comparing with impacts on environment.

A comparative analysis of metabarcoding and morphology-based identification of benthic communities across different regional seas.

In a world of declining biodiversity, monitoring is becoming crucial. Molecular methods, such as metabarcoding, have the potential to rapidly expand our knowledge of biodiversity, supporting assessment, management, and conservation. In the marine environment, where hard substrata are more difficult to access than soft bottoms for quantitative ecological studies, Artificial Substrate Units (ASUs) allow for standardized sampling. We deployed ASUs within five regional seas (Baltic Sea, Northeast Atlantic Ocean, Mediterranean Sea, Black Sea, and Red Sea) for 12-26 months to measure the diversity and community composition of macroinvertebrates. We identified invertebrates using a traditional approach based on morphological characters, and by metabarcoding of the mitochondrial cytochrome oxidase I (COI) gene. We compared community composition and diversity metrics obtained using the two methods. Diversity was significantly correlated between data types. Metabarcoding of ASUs allowed for robust comparisons of community composition and diversity, but not all groups were successfully sequenced. All locations were significantly different in taxonomic composition as measured with both kinds of data. We recovered previously known regional biogeographical patterns in both datasets (e.g., low species diversity in the Black and Baltic Seas, affinity between the Bay of Biscay and the Mediterranean). We conclude that the two approaches provide complementary information and that metabarcoding shows great promise for marine monitoring. However, until its pitfalls are addressed, the use of metabarcoding in monitoring of rocky benthic assemblages should be used in addition to classical approaches rather than instead of them.

Assessment of biopollution in aquatic ecosystems.

The introduction of alien species (AS) in marine environments is a factor of disturbance that can be viewed as a pollution agent. Using basic information on abundance and distribution of alien species, we developed an index that classifies AS impacts on native species, communities, habitats and ecosystem functioning. This method can be used to evaluate impact at five different levels of biopollution, fitting within the existing schemes for water quality assessment. Both spatial and temporal comparisons are possible. The assessments may also be used to evaluate management performance where avoidance measures were necessary and assist in preventing further unwanted introductions. Such assessments made for the same areas over time provide opportunities for measuring change in biopollution. We have tested the method using four different well-studied areas within the Baltic Sea (brackish to freshwater environments) for two different times, 20 years apart. Further developments of the scheme may be needed to cover some specific cases and taxonomic groups according to their life history.

The concept of biotope in marine ecology and coastal management.

The term "biotope" was introduced by a German scientist, Dahl in 1908 as an addition to the concept of "biocenosis" earlier formulated by Möbius (1877). Initially it determined the physical-chemical conditions of existence of a biocenosis ("the biotope of a biocenosis"). Further, both biotope and biocenosis were respectively considered as abiotic and biotic parts of an ecosystem. This notion ("ecosystem = biotope + biocenosis") became accepted in German, French, Russian and other European "continental" ecological literature. The new interpretation of the term ("biotope = habitat + community") appeared in the United Kingdom in the early 1990s while classifying "marine habitats" of the coastal zone. Since then, this meaning was also used in international European environmental documents. This paper examines the evolution of the biotope notion. It is concluded that the contemporary concept is robust and may be used not only for the classification and mapping but also for functional marine ecology and coastal zone management.

Assessing exemptions under the ballast water management convention: preclude the Trojan horse.

The International Maritime Organization (IMO) Ballast Water Management Convention (BWMC) is a powerful instrument aimed at reducing spread of harmful aquatic organisms and pathogens (HAOPs). As BWMC is expected to enter into force soon, shipping companies will start seeking exemptions for ballast water management in accordance with BWMC Regulation A-4. However, without scientifically robust risk assessment (RA) and consistent rules, the exemptions may introduce a new form of risk within a convention generally designed to reduce risks. This paper describes an adaptive system for granting exemptions, consisting of six major components: target species selection procedure, port-to-port RA, monitoring, information support, administrative decision and review process. The system is based on key principles defined in the IMO guidelines for RA and is designed to continuously accumulate evolving experience on granting exemptions. The ultimate goal is to contribute to the control of the spread of HAOPs, without placing an unnecessary burden on the shipping industry.

Rapid assessment of target species: Byssate bivalves in a large tropical port.

Rapid assessment sampling for target species is a fast cost-effective method aimed at determining the presence, abundance and distribution of alien and native harmful aquatic organisms and pathogens that may have been introduced by shipping. In this study, the method was applied within a large tropical port expected to have a high species diversity. The port of Kaohsiung was sampled for bivalve molluscan species that attach using a byssus. Such species, due to their biological traits, are spread by ships to ports worldwide. We estimated the abundance and distribution range of one dreissenid (Mytilopsis sallei) and four mytilids (Brachidontes variabilis, Arcuatula senhousa, Mytilus galloprovincialis, Perna viridis) known to be successful invaders and identified as potential pests, or high-risk harmful native or non-native species. We conclude that a rapid assessment of their abundance and distribution within a port, and its vicinity, is efficient and can provide sufficient information for decision making by port managers where IMO port exemptions may be sought.

Trophic interactions between indigenous and non-indigenous species in Lampedusa Island, Mediterranean Sea.

Using stable isotope analysis, we investigated trophic interactions between indigenous benthic taxa and the non-indigenous species (NIS): the green alga Caulerpa cylindracea, the red alga Asparagopsis taxiformis, the crab Percnon gibbesi and the sea hare Aplysia dactylomela. The study was conducted on Lampedusa Island, Mediterranean Sea. We evaluated the trophic positions and isotopic niches of consumers. Using Bayesian mixing models, we quantified the food source contribution to diets of indigenous and non-indigenous herbivores. Isotopic niche of NIS showed no overlap with the ones of indigenous macroinvertebrates and fish. Caulerpa cylindracea provided the largest contribution to the diet of P. gibbesi (0.431-1), while the dietary contribution estimates overlapped considerably for all sources of A. dactylomela and indigenous herbivores. From these results, we conclude that the invasion of C. cylindracea is increasing the diversity of available prey and might facilitate the expansion of other NIS.

Recommendations on methods for the detection and control of biological pollution in marine coastal waters.

Adverse effects of invasive alien species (IAS), or biological pollution, is an increasing problem in marine coastal waters, which remains high on the environmental management agenda. All maritime countries need to assess the size of this problem and consider effective mechanisms to prevent introductions, and if necessary and where possible to monitor, contain, control or eradicate the introduced impacting organisms. Despite this, and in contrast to more enclosed water bodies, the openness of marine systems indicates that once species are in an area then eradication is usually impossible. Most institutions in countries are aware of the problem and have sufficient governance in place for management. However, there is still a general lack of commitment and concerted action plans are needed to address this problem. This paper provides recommendations resulting from an international workshop based upon a large amount of experience relating to the assessment and control of biopollution.

Assessing impacts of invasive phytoplankton: the Baltic Sea case.

There is an increasing understanding and requirement to take into account the effects of invasive alien species (IAS) in environmental quality assessments. While IAS are listed amongst the most important factors threatening marine biodiversity, information on their impacts remains unquantified, especially for phytoplankton species. This study attempts to assess the impacts of invasive alien phytoplankton in the Baltic Sea during 1980-2008. A bioinvasion impact assessment method (BPL - biopollution level index) was applied to phytoplankton monitoring data collected from eleven sub-regions of the Baltic Sea. BPL takes into account abundance and distribution range of an alien species and the magnitude of the impact on native communities, habitats and ecosystem functioning. Of the 12 alien/cryptogenic phytoplankton species recorded in the Baltic Sea only one (the dinoflagellate Prorocentrum minimum) was categorized as an IAS, causing a recognizable environmental effect.

Status of biodiversity in the Baltic Sea.

The brackish Baltic Sea hosts species of various origins and environmental tolerances. These immigrated to the sea 10,000 to 15,000 years ago or have been introduced to the area over the relatively recent history of the system. The Baltic Sea has only one known endemic species. While information on some abiotic parameters extends back as long as five centuries and first quantitative snapshot data on biota (on exploited fish populations) originate generally from the same time, international coordination of research began in the early twentieth century. Continuous, annual Baltic Sea-wide long-term datasets on several organism groups (plankton, benthos, fish) are generally available since the mid-1950s. Based on a variety of available data sources (published papers, reports, grey literature, unpublished data), the Baltic Sea, incl. Kattegat, hosts altogether at least 6,065 species, including at least 1,700 phytoplankton, 442 phytobenthos, at least 1,199 zooplankton, at least 569 meiozoobenthos, 1,476 macrozoobenthos, at least 380 vertebrate parasites, about 200 fish, 3 seal, and 83 bird species. In general, but not in all organism groups, high sub-regional total species richness is associated with elevated salinity. Although in comparison with fully marine areas the Baltic Sea supports fewer species, several facets of the system's diversity remain underexplored to this day, such as micro-organisms, foraminiferans, meiobenthos and parasites. In the future, climate change and its interactions with multiple anthropogenic forcings are likely to have major impacts on the Baltic biodiversity.