The Groundbreaking Discovery of Silver Eels in Cyprus

In a significant advancement for marine biology and conservation science, researchers from Bournemouth University have documented the presence of silver stage European eels, scientifically known as Anguilla anguilla, in the inland freshwater systems of Cyprus for the very first time. This finding, detailed in a newly published study in the Journal of Fish Biology, marks the easternmost recorded occurrence of these mature migrating eels, extending the known range of the species into previously uncharted territories in the eastern Mediterranean. The discovery not only reshapes our understanding of the eel's distribution but also carries profound implications for regional conservation strategies across Europe.

The research team captured mature silver eels attempting seaward migration from two distinct locations: Oroklini Lake, a Natura 2000 protected site, and the fragmented Polis River in the Paphos region. This breakthrough confirms that juvenile eels, arriving as glass eels from the distant Sargasso Sea, can survive, grow, and mature in Cypriot waters despite challenging environmental conditions. Previously, only earlier life stages like yellow eels had been detected through environmental DNA surveys, leaving a critical gap in knowledge about the species' reproductive potential in this area.

Deciphering the European Eel's Complex Life Cycle

The European eel, Anguilla anguilla, exhibits one of the most extraordinary life cycles in the animal kingdom, a catadromous pattern that spans continents and oceans. It begins in the Sargasso Sea in the western Atlantic, where adults spawn and die. Their larvae, called leptocephali, drift on ocean currents for up to three years before metamorphosing into transparent glass eels upon reaching coastal waters. These glass eels then enter estuaries and rivers as pigmented elvers, transitioning into yellow eels that reside in freshwater habitats for 5 to 20 years, feeding and growing.

The pivotal silver stage occurs when the eel matures physiologically for reproduction. External changes include a silvering belly, enlarged eyes for deep-water vision, a fattened body, and altered fins—morphological adaptations assessed via indices like the Durif silvering stages (I to V). Silver eels then embark on an epic 4,000-6,000 kilometer migration back to the Sargasso Sea, navigating without feeding, powered by stored energy. This study's confirmation of stage IV/V silver eels in Cyprus underscores the full life cycle's presence at the species' range edge, highlighting remarkable resilience amid declines.

• Leptocephali: Leaf-like larvae drifting across the Atlantic.
• Glass eels: Transparent post-larvae entering brackish waters.
• Elvers/Yellow eels: Freshwater growth phase, up to two decades.
• Silver eels: Mature migrants heading to spawn.

Bournemouth University's Pioneering Fish Ecology Research

Bournemouth University (BU), located in the UK, has long been a hub for innovative aquatic research through its Fish Ecology and Conservation Research Cluster (FishE). Led by experts like Professor J. Robert Britton, the cluster focuses on threatened species and habitats, producing evidence-based insights for policy. This Cyprus study exemplifies BU's commitment, with researcher Sotiris Meletiou spearheading fieldwork. Meletiou, affiliated with both BU and Cyprus University of Technology, noted, “Our surveys targeted habitats and periods where silvering and migration were most likely, confirming mature silver eels at the easternmost edge of the range.”

Dr. Demetra Andreou, BU's Principal Academic in Environmental Science, analyzed data revealing how river dynamics affect populations. BU's involvement positions it as a leader in European higher education's response to biodiversity crises, offering students hands-on opportunities in field ecology. For aspiring researchers, platforms like higher ed research jobs showcase similar roles in conservation biology across Europe.

The FishE group's recent outputs, including papers on bream movements and shad mortality, amplify BU's impact, fostering collaborations that drive actionable science.

Cross-Border Collaborations Strengthening European Research

This study thrives on pan-European partnerships, uniting Bournemouth University with the University of the Highlands and Islands in Inverness, Scotland; Cyprus University of Technology; and the UK's Environment Agency. Nathan P. Griffiths from Inverness contributed expertise in biodiversity conservation, while Dr. Marlen I. Vasquez from Cyprus analyzed local data, emphasizing, “This unexploited population offers Cyprus a chance to contribute to eel recovery; an Eel Management Plan is urgently needed.”

Dr. Rosalind M. Wright from the Environment Agency highlighted eel resilience in drought-prone areas. Such collaborations exemplify how European universities pool resources for transboundary challenges, enhancing research capacity. In Cyprus, the Cyprus University of Technology's geotechnical sciences faculty bridges engineering and ecology, vital for habitat restoration. These ties underscore higher education's role in EU-wide initiatives, with opportunities detailed on sites like Europe university jobs.

Detailed Methodology and Captivating Field Findings

The team's methodology combined targeted surveys with precise morphometrics. At Oroklini Lake, fyke nets captured 473 silver eels (38.2–68 cm long, 120–555 g) after heavy December 2024 rains caused overflow. In the Polis River, electric fishing yielded five silver eels (>10 km inland) in February 2025. Eels were assessed using Durif criteria: enlarged eyes (eye index >4%), pectoral fins, and pigmentation confirmed stage IV/V.

Environmental data (temperature, oxygen, pH) contextualized captures, revealing negative correlations with coastal distance and barriers. Historical eDNA and electrofishing validated recruitment. Images from the field, such as those of silver eels in nets, vividly capture the moment: .

This rigorous approach ensures robust data, setting a model for replicable conservation studies.

Spotlight on Capture Sites: Oroklini and Polis River

Oroklini Lake, a coastal lagoon disconnected by construction, overflowed post-rain, enabling mass escapement attempts—yet barriers trapped eels, necessitating manual sea transport. Polis River's fragmentation, with dry sections, allowed upstream juvenile migration but delayed silver eels, risking de-silvering or mortality.

These sites illustrate microhabitat dynamics: low-elevation suitability for yellow eels, but anthropogenic pressures hinder full cycles. . Findings urge reconnection efforts, aligning with EU directives.

The Dire Conservation Status of European Eels

Listed as Critically Endangered by IUCN since 2008, A. anguilla populations have plummeted 90-95% since the 1980s due to overfishing, habitat loss, pollution, parasites (Anguillicola crassus), and climate extremes. Spawning stock biomass is at historic lows, with glass eel recruitment down 90%+ in some areas.

In Europe, annual catches once exceeded 10,000 tonnes; now restricted. Cyprus's unexploited stocks represent a rare hope. Multi-perspective views—from ICES advising zero catches in 2026 to NGO calls for bans—stress holistic recovery. Higher ed researchers drive this agenda, with career paths in academic CV building for conservation roles.

Policy Shifts: Cyprus Enters EU Eel Regulation Framework

EU Regulation (EC) No 1100/2007 mandates Eel Management Plans (EMPs) targeting 40% escapement of biomass. Cyprus gained exemption via 2009 Commission Decision, presuming negligible silver eels. This study voids that, demanding urgent EMP development.

Stakeholders, including local fisheries, must now assess biomass, reduce barriers, and monitor. Parallels in other nations: UK EMPs cut fishing 50%, aiding modest recoveries. For Cypriot academics, this opens grants; explore the full study or BU announcement.

Overcoming Habitat and Climatic Challenges

River damming (108 in Cyprus), drought, and warming waters exacerbate declines. Fragmentation blocks 70-90% of migrations in fragmented systems. Parasites reduce fitness by 20-50%. Solutions include eel passes, ramped weirs, and restoration—proven in Thames River Trust projects boosting escapement 300%.

• River reconnection via overflow channels.
• Telemetry tracking for migration routes.
• Climate-resilient habitat modeling.

European universities lead here, with BU's models informing actions.

Actionable Recommendations and Future Prospects

The study proposes: reconnect Oroklini Lake, quantify biomass, deploy telemetry, and enact EMPs. Broader: ban glass eel trade, expand marine protected areas. Future research eyes physiological markers and genetics to trace stocks.

Optimism lies in resilience shown—eels thriving in extremes. Higher ed's pivot to interdisciplinary work promises progress; see higher ed workforce insights.

Photo by Markus Winkler on Unsplash

Higher Education's Vital Role in Biodiversity Conservation

Universities like BU, Cyprus UT, and Inverness exemplify how higher education fuels discovery. PhD programs in ecology train the next generation, addressing shortages amid 20% research funding cuts in some EU states. Actionable: pursue faculty positions or scholarships in Europe.

Balanced views: while breakthroughs inspire, critics note slow policy uptake. Yet, student-led monitoring expands data, positioning academia as stewards. Internally, rate my professor tools aid career navigation.

In conclusion, this discovery galvanizes action. Explore higher ed jobs, career advice, and university jobs to join the effort.