Stelios Katsanevakis

University of the Aegean · Department of Marine Sciences

Conventional sectoral management and piecemeal governance are considered less and less appropriate in pursuit of sustainable development. Ecosystem based marine spatial management (EB-MSM) is an approach that recognizes the full array of interactions within an ecosystem, including human uses, rather than considering single issues, species, or ecosy...

Aim: To develop a standardized, quantitative method for mapping cumulative impacts of invasive alien species on marine ecosystems. Location: The methodology is applied in the Mediterranean Sea but is widely applicable. Methods: A conservative additive model was developed to account for the Cumulative IMPacts of invasive ALien species (CIMPAL) on ma...

Like most ocean regions today, the European and contiguous seas experience cumulative impacts from local human activities and global pressures. They are largely in poor environmental condition with deteriorating trends. Despite several success stories, European policies for marine conservation fall short of being effective. Acknowledging the challe...

Biological invasions have become a defining feature of marine Mediterranean ecosystems with significant impacts on biodiversity, ecosystem services, and human health. We systematically reviewed the current knowledge on the impacts of marine biological invasions in the Mediterranean Sea. We screened relevant literature and applied a standardised fra...

A literature review was conducted to investigate marine global and local extinctions and their drivers; the review followed the PRISMA-EcoEvo guidelines. The data extracted was enhanced with status assessments from the IUCN Red List. We recorded local extinctions for 717 species, of which 18 were global extinctions. Most of these extinctions were r...

The endemic Mediterranean fan mussel Pinna nobilis is on the brink of extinction due to an infectious disease that has caused an ongoing Mediterranean Mass Mortality Event (MME) since 2016. Currently, healthy P. nobilis populations can only be found in a few refuges, mainly transitional waters such as coastal lagoons and estuaries. In the eastern M...

Systematic conservation planning (SCP) is essential for meeting global conservation goals and mitigating anthropogenic impacts on biodiversity. Effective conservation planning should incorporate the threedimensional nature of ecosystems, including species distribution by depth. Recent advancements, like the 3D prioritization approach, address this...

This presentation is about two main drivers of biodiversity changes in the Mediterranean Sea: climate change and biological invasions. The Mediterranean Sea is a global hotspot for both climate change and biological invasions, which have caused substantial changes in distribution patterns and species composition, with local extinctions or declines...

Jellyfish and gelatinous zooplankton (GZ) in general, fulfill important ecological roles with significant impacts, although they are often oversimplified or misunderstood. This paper reviews the impacts, pressures, monitoring methods and current management strategies for various GZ groups. It also introduces potentially applicable indicators for their...

The Pinna nobilis, a Mediterranean mollusc, has suffered population declines due to a massive mortality event associated with various factors including the parasite Haplosporidium pinnae. Some populations show resilience, possibly due to local environmental conditions. In this study, a molecular multiplex PCR method was developed using species‐spec...

The Barcelona Convention (BC) aims at biodiversity conservation in the Mediterranean Sea, including in its Annex II a list of threatened species that need protection. This study aimed to assess existing scientific effort and knowledge on the invertebrate species of BC Annex II, through a systematic literature review. For the 52 invertebrates of Ann...

Until the summer of 2023, the only known Pinna species in the Greek seas was Pinna nobilis. A mass mortality event that began in 2016 in the Mediterranean pushed P. nobilis on the brink of extinction. In the summer of 2023, photos of live Pinna individuals were uploaded on social media. Targeted surveys and molecular analyses revealed that the spec...

The endemic Mediterranean bivalve Pinna nobilis (Linnaeus 1758) is currently classified as Critically Endangered, following a mass mortality event (MME) which initiated in 2016 and decimated its populations. The primary cause of the MME is considered to be the spread of the cryptogenic parasite Happlosporidium pinnae, with other pathogens also cont...

We aimed to assess the social-ecological roles of marine alien species in the eastern Mediterranean Sea – a global hotspot of bioinvasions and local extinctions – and their potential contribution to reaching Targets 1, 3, 10, and 11 of the Kunming-Montreal Global Biodiversity Framework (GBF). We employed a comprehensive methodology, incorporating a...

The conservation and management of marine ecosystems hinge on a comprehensive understanding of the status and trends of top predators. This review delves into the ecological significance of marine top predators, examining their roles in maintaining ecosystem stability and functioning through an integrated analysis of current scientific literature....

Conserving marine megafauna is a complex task, particularly due to the gaps in our knowledge regarding their distribution and susceptibility to human pressures. While the Ionian Sea, eastern Mediterranean, is renowned for hosting nesting sites for sea turtles and supporting diverse cetacean populations, identifying key marine habitats for elusive s...

The Mediterranean endemic bivalve, Pinna nobilis, has been experiencing ongoing mass mortality since 2016, attributed to the parasite Haplosporidium pinnae. In Greece, only two populations remain, one located in Kalloni Gulf in Lesvos and the other in Amvrakikos Gulf. The objective of this study was to evaluate the status of the remaining populatio...

This study examines the taxonomic composition of biofouling communities in two fishing ports of Kalloni Gulf (Lesvos Island, Greece), focusing on the detection of alien and cryptogenic species. Using PVC plates for biofouling monitoring, we identified 14 benthic species, including three alien and three cryptogenic species. Monitoring involved bi-we...

The fan mussel Pinna nobilis (L., 1758), a critically endangered endemic Mediterranean species, has witnessed a substantial population decline throughout the Mediterranean attributed to mass mortality events (MMEs), notably beginning in Autumn 2016. The MMEs have been linked to the presence of the parasite Haplosporidium pinnae, although Mycobacter...

Population declines of vertebrates are common, but rebuilding marine life may be possible. We assessed trends in sea turtle numbers globally, building 61 time series of abundance extending beyond 2015, representing monitoring in >1200 years. Increases were widespread with significant upward trends, no significant change, and significant downward tr...

Area-based fisheries management measures (ABFMs) have evolved beyond fisheries regulation to encompass broader conservation goals. This mini-review provides key recommendations to guide the science-based implementation of effective ABFMs for rebuilding fisheries and conserving marine biodiversity within the Kunming-Montreal Global Biodiversity Fram...

This scoping review (ScR) protocol aims to establish the methodological approach for identifying and mapping the evidence regarding the actual contribution of Other Effective area-based Conservation Measures (OECMs) to spatial conservation targets. Emphasis will be placed on examining the research conducted, including the methodologies applied. OEC...

Human activities at sea have increased, causing subsequent degradation of ocean health and affecting ecosystem services and societal goods and benefits. Climate change further exacerbates the cumulative effects of these activities and their associated pressures. Hence, effective management of these multiple activities is imperative to ensure the su...

Coastal areas provide cultural ecosystem services that contribute to the well-being of society, but these areas are often undervalued due to methodological challenges. Assessment of the economic value of beach recreation is crucial for effective coastal management and conservation. This paper presents a comprehensive evaluation of recreational ecos...

In the Mediterranean Sea, the genus Pinna encompasses two large fan-shaped bivalve species, Pinna nobilis and Pinna rudis. Historically, both species coexisted in the western Mediterranean until a mass mortality event (MME) brought P. nobilis to the brink of extinction. Notably, P. rudis remained unaffected by the MME, and its recent successful rec...

Since the first confirmed records of mass mortality events (MME) in the Aegean Sea in 2018, Pinna nobilis populations in Greek seas have been decimated. To bolster recovery efforts, this study aimed to assess the status of fan mussel populations in the Aegean and Ionian seas and investigate potential recolonization through natural recruitment. From...

The Aegean Sea stands as a unique Mediterranean ecoregion with intricate geomorphological attributes and diverse habitats. This article delves into the sea’s rich biodiversity and the challenges of managing its resources sustainably. The Aegean’s complex structure encompasses shallow shelves, deep basins, and a multitude of habitats, mirrored by a...

Marine harmful algal blooms (HABs), caused by various aquatic microalgae, pose significant risks to ecosystems, some socio-economic activities and human health. Traditionally managed as a public health issue through reactive control measures such as beach closures, seafood trade bans or closure of mollusc production areas, the multifaceted linkages...

This scoping review (ScR) protocol aims to establish the methodological approach for identifying and mapping the evidence regarding the actual contribution of Other Effective area-based Conservation Measures (OECMs) to spatial conservation targets. Emphasis will be placed on examining the research conducted, including the methodologies applied. OEC...

Cultural ecosystem services (CES) provide a range of aesthetic and recreational benefits. However, they have not been extensively assessed due to methodological challenges, despite their use and non-use values for local and wider communities. Therefore, this study aimed to assess the economic importance and spatial distribution of recreational divi...

European islands are hotspots of biological and cultural diversity, which, compared to mainland, are more vulnerable to climate change, tourism development, uncontrolled land-use changes and the consequences of financial crisis. These drivers of change have increasingly resulted in severe impacts on socio-economic and environmental parameters. Proj...

The worldwide decline of macroalgal forests is raising major concerns for the potentially negative consequences on biodiversity and ecosystem functions, pushing for the definition of specific conservation and restoration measures. Protecting and restoring these habitats requires detailed information on their distribution, ecological status, and dri...

Biological invasions, resulting from human activities, exert substantial impacts on ecosystems worldwide. This review focuses on marine invasive alien species (IAS) in Europe, examining the current state, proposing strategies to address the problem, and offering recommendations for enhanced management. Effective management of biological invasions r...

Over the past few decades, the scientific community has extensively investigated microplastics (MPs) and their interactions with marine organisms. MPs ingestion has been one of the most commonly examined topics across marine fauna. In this study, we present a systematic review conducted to gather information on the MPs ingestion by different taxono...

Background: Systematic Conservation Planning (SCP) involves a series of steps to identify conservation areas and develop management strategies, incorporating feedbacks, revisions, and iterations at any stage. It is a valuable tool in facilitating the effective implementation of Ecosystem-Based Marine Spatial Planning (EB-MSP). However, few efforts...

In the Mediterranean Sea, the genus Pinna encompasses two large fan-shaped bivalve species, Pinna nobilis and Pinna rudis. Historically, both species coexisted in the western Mediterranean until a Mass Mortality Event brought P. nobilis to the brink of extinction. Notably, P. rudis remained unaffected by the MME, and its recent successful recruitme...

An assessment framework of marine ecosystem services (ES) indicators to quantify the socio-ecological effectiveness of nature-based solutions (NBS) and nature-inclusive harvesting (NIH) under climate-driven changes was developed. It creates a common understanding about the health status of ecosystems, their services (ES), and the impact of implemen...

A meta-analysis and map of the monetary value of Meditteranean seagrass ecosystem services. The Mediterranean ecosystem services are valued at 6.7 billion dollars, emphasizing the need to protect these "hidden treasures". This valuation helps policymakers and stakeholders recognize the tangible benefits provided by seagrass meadows, which can lead...

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 unnot...

This scoping review (ScR) protocol aims to establish the methodological approach for identifying and mapping the evidence regarding the actual contribution of Other Effective area-based Conservation Measures (OECMs) to spatial conservation targets. Emphasis will be placed on examining the research conducted, including the methodologies applied, and...

Biological invasions are a human-induced environmental disturbance that can cause major changes in ecosystem structure and functioning. Located in the northeastern Mediterranean basin, the Aegean Sea is a hotspot of biological invasions. Although the presence of alien species in the Aegean has been studied and monitored, no assessment has been cond...

Marine heatwaves (MHWs) are periods of abnormally warm ocean temperatures that severely impact marine ecosystems. Although they can propagate beneath the ocean’s surface, MHWs are typically assessed using sea surface temperatures. Here, we investigated the future evolution and depth penetration of MHWs across the Mediterranean basin. Our analysis r...

The degradation of marine ecosystems is a growing concern worldwide, emphasizing the need for efficient tools to assess their ecological status. Herein, a novel ecosystem-based ecological evaluation index of shallow rocky reefs is introduced and tested in the Aegean and Ionian Seas (NE Mediterranean). The index focuses on a specific set of pre-sele...

Mediterranean rocky reefs are undergoing regime shifts, from a structurally complex and diverse state dominated by canopy forming macroalgae to a degraded one characterised by low-lying turf or encrusting macroalgal species, due to increased anthropogenic pressure and climate change. Using data gathered from 89 sites across the entire Aegean Sea, t...

Canopy-forming macroalgae, such as Cystoseira sensu lato, increase the three-dimensional complexity and spatial heterogeneity of rocky reefs, enhancing biodiversity and productivity in coastal areas. Extensive loss of canopy algae has been recorded in recent decades throughout the Mediterranean Sea due to various anthropogenic pressures. In this st...

Area-based fisheries management measures (ABFMs) are commonly related to the sustainable use of resources but are increasingly considered broader conservation measures. This Scoping Review (ScR) identified and mapped the evidence base regarding the contribution of ABFMs to fisheries sustainability and marine conservation. The ScR was conducted foll...

Biological invasions are a human-induced environmental disturbance that can cause major changes in ecosystem structure and functioning. Located in the northeastern Mediterranean basin, the Aegean Sea is a hotspot of biological invasions. Although the presence of alien species in the Aegean has been studied and monitored, no assessment has been cond...

As climate-related impacts threaten marine biodiversity globally, it is important to adjust conservation efforts to mitigate the effects of climate change. Translating scientific knowledge into practical management, however, is often complicated due to resource, economic and policy constraints, generating a knowledge-action gap. To develop potentia...

We used Ecopath with Ecosim to describe the structure and functioning of the shelf ecosystem of the island of Cyprus (eastern Mediterranean) and simulate a series of scenarios related to fisheries and ecosystem management strategies. Analysis was based on a previous 2015–17 model of the same ecosystem, updated with recent data on recreational catch...

The Greek Seas are greatly exposed to the proliferation of marine alien species. At least 242 alien species have been reported within Greek territorial waters, three-quarters of which are considered established, while their rate of introduction is increasing. Some of these species exhibit high invasiveness, imposing severe impacts on native ecosyst...

To enrich spatio-temporal information on the distribution of alien, cryptogenic, and neonative species in the Mediterranean and the Black Sea, a collective effort by 173 marine scientists was made to provide unpublished records and make them open access to the scientific community. Through this effort, we collected and harmonized a dataset of 12,64...

Rapid anthropogenic climate change is driving threatened biodiversity one step closer to extinction. Effects on native biodiversity are determined by an interplay between species' exposure to climate change and their specific ecological and life-history characteristics that render them even more susceptible. Impacts on biodiversity have already bee...

Marine caves are protected habitats with high biodiversity and low ecological resilience, vulnerable to multiple pressures including biological invasions. Therefore, comprehensive lists of alien species in sea caves and assessments of their impacts are urgently needed. This study aimed to provide an updated and validated list of introduced species...

Truly sustainable development in a human-altered, fragmented marine environment subject to unprecedented climate change, demands informed planning strategies in order to be successful. Beyond a simple understanding of the distribution of marine species, data describing how variations in spatio-temporal dynamics impact ecosystem functioning and the...

In the past years, efforts have been made to include connectivity metrics in conservation planning in order to promote and enhance well-connected systems of protected areas. Connectivity is particularly important for species that rely on more than one realm during their daily or life cycle (multi-realm species). However, conservation plans for the...

A coral bank of the scleractinian Cladocora caespitosa is documented for the first time in the Gulf of Kalloni, Lesvos Island, Greece. It is among the largest Cladocora reefs in the Mediterranean, and corals can be found up to 5.8 m depth. Overall, 1,492 colonies were visually sampled in situ by scuba divers to assess colony size, coral surface are...

In an effort to track the progress of the Pinna nobilis mass mortality event in Greece by 2022, the present study attempted to assess the status of fan mussel populations in the Aegean and Ionian Seas by means of underwater visual surveys.

Stamatiadou, V, Mazaris, A, Mallios, Z, & Katsanevakis, S 2022, ‘Marine protected areas and recreational diving in the Aegean Sea’, paper presented at the 4th ESP Europe Conference: Ecosystem services empowering people and societies in times of crises, Heraklion, Greece, 10-14 October 2022.

Brachiopods, though common in marine caves, have been so far rarely reported from caves of the Eastern Mediterranean Sea. Herein we present new records of brachiopods collected in eleven marine caves located on eight Greek islands (Kastelorizo, Rhodes, Crete, Samos, Agios Efstathios, Polyaigos, Pantieronissi and Skyros). Four species (60 individual...