Methodological challenges in assessing the environmental status of a marine ecosystem: Case study of the Baltic Sea

Assessments of the environmental status of marine ecosystems are increasingly needed to inform management decisions and regulate human pressures to meet the objectives of environmental policies. This paper addresses some generic methodological challenges and related uncertainties involved in marine ecosystem assessment, using the central Baltic Sea as a case study. The objectives of good environmental status of the Baltic Sea are largely focusing on biodiversity, eutrophication and hazardous substances. In this paper, we conduct comparative evaluations of the status of these three segments, by applying different methodological approaches. Our analyses indicate that the assessment results are sensitive to a selection of indicators for ecological quality objectives that are affected by a broad spectrum of human activities and natural processes (biodiversity), less so for objectives that are influenced by a relatively narrow array of drivers (eutrophications, hazardous substances). The choice of indicator aggregation rule appeared to be of essential importance for assessment results for all three segments, whereas the hierarchical structure of indicators had only a minor influence. Trend-based assessment was shown to be a useful supplement to reference-based evaluation, being independent of the problems related to defining reference values and indicator aggregation methodologies. Results of this study will help in setting priorities for future efforts to improve environmental assessments in the Baltic Sea and elsewhere, and to ensure the transparency of the assessment procedure

Over one decade of invasion: the non-indigenous cladoceran Evadne anonyx G.O. Sars, 1897 in a low-salinity environment

Invasive species are often in focus in the non-indigenous species (NIS) research while low-abundance species receive relatively little attention. However, tracking NIS dynamics since the early stages of an invasion provides valuable information on the ecology of invasions. In the current paper, we investigated the invasion history and population dynamics of the small-bodied cladoceran Evadne anonyx G. O. Sars, 1897 in the Gulf of Riga (Baltic Sea) almost since its first detection in 2000. The species already was widespread the Gulf of Riga in 2001 and has been found in nearly every subsequent sample collected during summer months. However, the abundance of the species remained low, seldom 100 individuals m-3. Both, salinity and water temperature affected the spatial distribution and population abundance of E. anonyx. The species was found to occur only sporadically at salinities below ca. 6. To obtain reliable presence/absence and density estimates on this small-bodied cladoceran, the entire zooplankton sample needed to be analysed

Multidisciplinary perspectives on the history of human interactions with life in the ocean

Abstract There is an essentially circular interaction between the human social system and the marine ecosystem. The Oceans Past V Conference “Multidisciplinary perspectives on the history of human interactions with life in the ocean” held in Tallinn, Estonia, in May 2015 was an opportunity for the presentation and discussion of papers on a diverse array of topics that examined this socio-ecological system from a historical perspective. Here we provide background to the disciplines participating in the conference and to the conference itself. We summarize the conference papers that appear in this special volume of the ICES JMS and highlight issues which arose during general discussion. We make two conclusions. First, to have greater impact and ensure more efficient use of knowledge gained from marine historical ecology (MHE) and marine environmental history (MEH) in ecosystem-based management and related policy development, practitioners need to work more routinely with population and ecological modellers and statisticians. This will allow greater processing of the available historical data to derive ecologically meaningful properties that can then be used to assess the ecological impact of long-term changes of affected species and define appropriate and realistic management targets. Second, increased multi- and trans-disciplinary effort is required to better understand the relative importance of different human demographic, technological, economic, and cultural drivers on the patterns, intensities and trajectories of human activities affecting marine ecosystems.</jats:p

Female ovarian abnormalities and reproductive failure of autumn-spawning herring (Clupea harengus membras) in the Baltic Sea

Fecundity and reproductive potential are important factors to be considered in evaluating trajectories and demographic predictions of fish populations. Therefore, characterizing the nature and quantifying the extent of any reproductive failure should be considered in fisheries studies. Here, we describe morphological changes in developed ovaries of autumn-spawning herring (Clupea harengus membras) caught in the northern Baltic Sea and evaluate the magnitude of this phenomenon during 3 consecutive years. Visibly, abnormal ovaries were histologically characterized by irregular-shaped oocytes in a vitellogenic or final maturation stage with coagulative necrosis and liquefaction of the yolk sphere, degraded follicle membranes, and fibrinous adhesion among oocytes. Such degeneration is presumed to cause complete infertility in the fish. The frequency of fish with abnormal ovaries varied annually between 10 and 15% among all females sampled. However, specific sampling events showed up to 90% females with abnormal gonads. The specific cause of this abnormality remains unknown; however, prevalence was associated with unfavourable environmental conditions encountered before spawning. Thus, ovarian abnormality was positively related to water temperatures, with the highest level found at ≥15°C and negatively related to the frequency of strong winds. The frequency of occurrence of abnormal gonads decreased with the progression of spawning from August to October. The observed abnormality and associated spawning failure will negatively affect the realized fecundity of autumn herring in the Baltic Sea and may act as a limiting factor for recovery of the stock, which has experienced profound depression during the last three decades

The global integrated world ocean assessment: linking observations to science and policy across multiple scales

In 2004, the United Nations (UN) General Assembly approved a Regular Process to report on the environmental, economic and social aspects of the world's ocean. The Regular Process for Global Reporting and Assessment of the State of the Marine Environment, including Socioeconomic Aspects produced the first global integrated assessment of the marine environment in December 2016 (known as the first World Ocean Assessment). The second assessment, to be delivered in December 2020, will build on the baselines included in the first assessment, with a focus on establishing trends in the marine environment with relevance to global reporting needs such as those associated with the UN Sustainable Development Goals. Central to the assessment process and its outputs are two components. First, is the utilization of ocean observation and monitoring outputs and research to temporally assess physical, chemical, biological, social, economic and cultural components of coastal and marine environments to establish their current state, impacts currently affecting coastal and marine environments, responses to those impacts and associated ongoing trends. Second, is the knowledge brokering of ocean observations and associated research to provide key information that can be utilized and applied to address management and policy needs at local, regional and global scales. Through identifying both knowledge gaps and capacity needs, the assessment process also provides direction to policy makers for the future development and deployment of sustained observation systems that are required for enhancing knowledge and supporting national aspirations associated with the sustainable development of coastal and marine ecosystems. Input from the ocean observation community, managers and policy makers is critical for ensuring that the vital information required for supporting the science policy interface objectives of the Regular Process is included in the assessment. This community white paper discusses developments in linking ocean observations and science with policy achieved as part of the assessment process, and those required for providing strategic linkages into the future.Agência financiadora - United Nations Division for Ocean Affairs and the Law of the Seainfo:eu-repo/semantics/publishedVersio

The enlargement of the Suez Canal and introduction of non-indigenous species to the Mediterranean Sea

The Suez Canal is one of the most important waterways in the world – during the last year 17,148 ships passed through the Canal – reducing emissions, saving time, and operating costs to shippers. The rapid increase in ship size from the “Post-Suezmax” (> 12,000 TEU) to the latest container vessels (> 19,000 TEU) now requires enlargements of port facilities and canals. A project of this magnitude, and with potentially negative environmental outcomes, requires a transparent and scientifically sound “Environmental Impact Assessment” (EIA). An explicit obligation on Parties to the Convention on Biological Diversity (https://www.cbd.int/doc/ legal/cbd-en.pdf) was made to consider transboundary impacts on biodiversity, particularly those associated with invasive non-indigenous species

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

A Census of Marine Biodiversity Knowledge, Resources, and Future Challenges

15 pages, 7 figures, 6 tablesThe Census of Marine Life (2000–2010) was the largest global research programme on marine biodiversity. This paper integrated the findings of reviews of major world regions by the Census and provides a global perspective on what is known and what are the major scientific gaps. Study metrics were regional species richness, numbers of endemic and alien species, numbers of species identification guides and taxonomic experts, and a state-of-knowledge index. The threats to biodiversity were classified across the regions. A poor to moderate correlation between species richness and seabed area, and sea volume, and no correlations with topographic variation, were attributed to sparse, uneven and unrepresentative sampling in much of the global marine environment. Many habitats have been poorly sampled, particularly in deeper seas, and several species-rich taxonomic groups, especially of smaller organisms, remain poorly studied. Crustacea, Mollusca, and Pisces comprised approximately half of all known species across the regions. The proportion that these and other taxa comprised of all taxa varied sufficiently to question whether the relative number of species within phyla and classes are constant throughout the world. Overfishing and pollution were identified as the main threats to biodiversity across all regions, followed by alien species, altered temperature, acidification, and hypoxia, although their relative importance varied among regions. The findings were replicated worldwide, in both developed and developing countries: i.e. major gaps exist in sampling effort and taxonomic expertise that impair society's ability to discover new species and identify and understand species of economic and ecological importance. There was a positive relationship between the availability of species identification guides and knowledge of biodiversity, including the number of species and alien species. Available taxonomic guides and experts correlated negatively with endemic species, suggesting that the more we study the ocean the fewer endemic species are evident. There is a need to accelerate the discovery of marine biodiversity, since much of it may be lost without even being known. We discuss how international collaboration between developed and developing countries is essential for improving productivity in the discovery and management of marine biodiversity, and how various sectors may contribute to thisThe contribution of HO was financed by research grant from the Estonian Ministry of Education and Research (no. SF0180005s10). MC was supported financially by the European Commission Marie Curie Post-doctoral Fellowship through the International Outgoing Fellowships (Call FP7-PEOPLE-2007-4-1-IOF) for the ECOFUN project and by Dalhousie University, Canada. RD was supported by the projects HERMIONE (EU-FPVII), VECTOR and OBAMA (MIUR, Italy). PM was supported by the Decanato de Investigación y Desarrollo, Universidad Simón BolívarPeer reviewe

The future of the oceans past : toward a global marine historical research initiative

Historical research is playing an increasingly important role in marine sciences. Historical data are also used in policy making and marine resource management, and have helped to address the issue of shifting baselines for numerous species and ecosystems. Although many important research questions still remain unanswered, tremendous developments in conceptual and methodological approaches are expected to contribute to a comprehensive understanding of the global history of human interactions with life in the seas. Based on our experiences and knowledge from the "History of Marine Animal Populations' project, this paper identifies the emerging research topics for future historical marine research. It elaborates on concepts and tools which are expected to play a major role in answering these questions, and identifies geographical regions which deserve future attention from marine environmental historians and historical ecologists