Lake Prespa
Lake Prespa consists of the larger Great Prespa Lake and the adjacent smaller Mikri Prespa Lake, forming a transboundary tectonic lake system shared by Albania, North Macedonia, and Greece in the Balkan Peninsula.[1] Located at an elevation of 853 meters above sea level, it represents one of the highest tectonic lakes in the region and among the oldest freshwater bodies in Europe.[2] The Great Prespa Lake covers a surface area of approximately 274 square kilometers, with a maximum depth of 55 meters.[3][4] This ancient lake sustains a hotspot of endemic biodiversity, including nine species of fish unique to its basin out of 23 total, and hosts the world's largest breeding colony of Dalmatian pelicans (Pelecanus crispus).[5] The surrounding basin features diverse habitats that support over 1,500 plant species and serves as a refuge for large mammals such as bears, wolves, and deer.[6] Hydrologically linked to Lake Ohrid via underground karst channels, Prespa contributes to a shared ecosystem of global significance.[7] Despite its ecological value, the lake faces pressures from water level declines attributed to reduced precipitation, climate variability, and agricultural abstractions, prompting trilateral conservation efforts among the bordering states.[8][9] Unique geological features, such as glacial-origin sandy beaches—the only ones among Balkan lakes—underscore its distinctiveness, though human activities like irrigation expansion have exacerbated environmental degradation.[10][6]Physical Characteristics
Location and Morphology
Lake Prespa occupies a transboundary position in the southeastern Balkan Peninsula, shared among North Macedonia in the northern section, Albania encompassing the eastern third, and Greece holding the southwestern portion including Mikri Prespa.[4][11] The primary basin, Great Prespa (also termed Megali or Macro Prespa), spans approximately 259 km² at an elevation of 845 meters above sea level.[4][3] The lake system comprises Great Prespa and the adjacent Little Prespa (Mikri or Micro Prespa), separated by a narrow land strip and linked by an artificial canal that maintains a hydraulic head difference of about 3 meters, with Little Prespa situated higher.[12][13] Great Prespa reaches a maximum depth of 55 meters, while Little Prespa attains only 8.4 meters.[4][14] Formed within a subsiding tectonic basin, the lake is bordered by karstic limestone mountains, including the Galičica range to the west and drier ridges to the east, with sedimentary infill in lower areas.[15][16] Inflows derive mainly from surface runoff via numerous small rivers draining the encircling highlands and direct precipitation, accounting for roughly 56% and 35% of inputs respectively.[12] The basin lacks surface outflow, with water exiting via karst aquifers beneath the Galičica mountains toward Lake Ohrid approximately 15 km northwest.[16][17]Geological Origins and Hydrology
Lake Prespa occupies a tectonic basin formed during the Pliocene epoch, approximately 2 to 5 million years ago, within the framework of Balkan rift-related extension and subsidence.[18] This ancient lake, among the oldest in Europe, persists due to sustained tectonic activity that maintains basin integrity amid regional uplift and faulting.[7] The underlying geology features granitic intrusions and extensive karstic limestone formations, which contribute to variable aquifer permeability and facilitate subterranean water movement.[19] Hydrologically, the lake receives inflows mainly from direct precipitation over its catchment (accounting for about 35% of input) and surface runoff via rivers and streams (roughly 56%), with minor contributions from upstream karst aquifers.[20] Its water balance is evaporation-dominated under the Mediterranean-continental climate regime, where summer aridity exceeds winter recharge, rendering the lake hypersensitive to precipitation deficits.[8] Outflow occurs primarily through karst conduits beneath the intervening mountains, draining to the lower-lying Lake Ohrid; environmental isotope analyses (e.g., δ¹⁸O and δ²H) and artificial tracer tests quantify this connection, showing that up to 52% of certain Ohrid springs derive from Prespa recharge.[21][22] Empirical records from lake springs reveal decadal fluctuations in bicarbonate ion concentrations (HCO₃⁻), correlating inversely with winter precipitation and directly with evaporative intensification during arid phases, underscoring the system's linkage to regional hydroclimatic variability over glacial-interglacial cycles.[23] These geochemical signals, derived from carbonate dissolution in karst inflows, provide proxies for past hydrological steady states without modern anthropogenic overlays.Historical Context
Prehistoric and Ancient Human Activity
Archaeological evidence reveals human settlement in the Lake Prespa basin during the Neolithic period, with the earliest dated occupation around 5200 BCE at sites such as Golem Grad island in the North Macedonian sector of the lake.[24] These lakeshore and island locations, situated at elevations of approximately 850 meters above sea level, indicate early communities reliant on fishing and rudimentary agriculture, exploiting the lake's aquatic resources within the broader Ohrid-Prespa hydrological continuum.[4] Artifact assemblages from these sites, including pottery and tools, reflect adaptation to the lacustrine environment predating major regional empires.[25] During the Bronze Age, settlement patterns intensified along the lake's shores, with numerous fortified sites documented across the tri-border area, signaling strategic use of the terrain for defense and resource access.[26] Excavations on Maligrad island in the Albanian sector yield evidence of activity from circa 1400 BCE, including structural remains atop promontories overlooking the water, consistent with broader basin trends of pile-dwelling or shore-based habitation.[24] Radiocarbon dating of organic materials from comparable lakeshore contexts in the Prespa-Ohrid system corroborates these chronologies, placing settlement phases between approximately 3000 and 1200 BCE and highlighting continuous human interaction with the ecosystem through fishing, hunting, and early pastoralism.[27] Such patterns underscore the basin's role as a stable refuge for prehistoric groups amid fluctuating post-glacial climates.[28]Medieval to Ottoman Eras
Following the Byzantine Empire's reconquest of the Balkans in the early 11th century after defeating Bulgarian Tsar Samuel in 1014 and fully incorporating the region by 1018, the Prespa basin remained under imperial administration for several centuries.[29] The area served as a frontier zone, with Byzantine military presence reinforced by fortifications and ecclesiastical establishments, including cave hermitages and monasteries that dotted the lakeshores.[30] These structures, such as the cavernous hermitage of the Nativity of the Virgin on Mali Grad island, exemplify post-iconoclastic Byzantine architecture adapted to the rugged terrain, featuring frescoes and rock-cut chapels dating to the 11th-14th centuries.[31] During the Comnenian restoration in the 12th century and amid the revival of Bulgarian power under the Second Bulgarian Empire (1185-1250), control over Prespa fluctuated, but Byzantine influence persisted through Orthodox monastic networks linking the lake to Ohrid's archbishopric.[29] Slavic settlements integrated with transhumant pastoralism, where highland Vlach and Albanian herders seasonally exploited lake fisheries and meadows without demarcated boundaries, fostering a multi-ethnic continuum.[4] The Serbian Empire under Stefan Dušan (r. 1331-1355) incorporated the region in the mid-14th century, extending Nemanjić rule southward and patronizing church constructions like the basilica at Agios Germanos, a cross-in-square edifice with dome supported by four pillars.[32][29] Ottoman expansion reached Prespa around 1386, integrating the basin into the Rumelia eyalet as a nahiye with mixed Christian-Muslim populations under timar system land grants.[4] Until the early 20th century, Ottoman governance maintained the undivided character of the lake, with local bey oversight of transhumance routes and taxation on fisheries, while Byzantine-era monasteries endured as pilgrimage sites amid gradual Islamicization in surrounding villages.[29] Enduring artifacts include post-Byzantine frescoed churches on islands like Agios Achilleios, reflecting cultural layering without erasure of Orthodox heritage.[33]19th-20th Century Border Delimitations and Conflicts
The borders encompassing Lake Prespa were delineated amid the Balkan Wars of 1912–1913, as Ottoman control over the Macedonian vilayets collapsed under assaults by the Balkan League. The Treaty of Bucharest, signed on 10 August 1913, concluded the Second Balkan War by apportioning contested territories: Greece secured southern Macedonia, incorporating the southern reaches of Great Prespa Lake and the bulk of Little Prespa Lake; Serbia obtained the northern segment of Great Prespa; while Albania, provisionally independent via the May 1913 Treaty of London, received delimited eastern fringes of Great Prespa through subsequent bilateral protocols, with the Greco-Albanian frontier transecting the western arm of Little Prespa.[34][35] These partitions, imposed by great-power arbitration and military outcomes, fragmented a cohesive ethnic landscape, predominantly inhabited by Slavic speakers, fostering irredentist claims and localized skirmishes over resource access.[29] World War II intensified border frictions through Axis occupations: from 1941, Bulgarian forces—aligned with the Axis—annexed swaths of Greek and Serbian Macedonia, extending administrative control to Prespa's environs until Allied liberation in 1944 restored pre-war lines.[36] The ensuing Greek Civil War (1946–1949) saw communist insurgents exploit the lake's tripartite periphery for cross-border operations, prompting Greece to militarize the zone and restrict civilian movement.[37] Cold War alignments entrenched divisions: Greece, as a NATO member, maintained Prespa under a fortified "border zone" regime with surveillance and access curbs; Albania's Stalinist isolation post-1948 severed ties with Yugoslavia (encompassing the northern lake shore); and ideological rifts precluded cooperative resource management until the 1990s.[29] North Macedonia's 1991 independence from Yugoslavia revived latent tensions, particularly Greece's veto on EU/NATO accession over the "Macedonia" nomenclature, which indirectly stalled Prespa-related initiatives. The Prespa Agreement of 17 June 2018, negotiated and signed adjacent to the lake in Greece's Psarades village, adjudicated this naming impasse—stipulating "North Macedonia" with qualifiers on heritage—without modifying territorial borders but enabling nascent environmental dialogues across the divided basin.[38][39]Biodiversity and Ecosystems
Vegetation and Habitats
The wetlands of Lake Prespa feature extensive reed beds primarily composed of Phragmites australis, forming dense stands along the littoral zones and supporting transitional habitats between open water and terrestrial ecosystems.[40][41] These reed communities exhibit seasonal dynamics, with spring inundation from elevated water levels expanding their extent into adjacent wet meadows, while summer drawdown exposes substrates for sediment deposition and root zone aeration.[42][43] Aquatic macrophyte communities dominate submerged and floating habitats within the lake, including species such as Ceratophyllum spp. and Myriophyllum spp., which form rooting or free-floating assemblages adapted to varying depths and nutrient levels.[44][45] These plants contribute to the shorezone's sedimentary flats, where fine alluvial deposits accumulate, fostering agriculture-proximate ecosystems with interspersed hygrophilous grasses and forbs that stabilize substrates against erosion.[43][46] Surrounding the basin, alpine and subalpine meadows prevail on limestone karst slopes above 1500 meters, characterized by herbaceous assemblages including endemic taxa influenced by the region's fractured karst hydrology and edaphic isolation.[47][48] The Prespa area's flora includes approximately 15.4% endemic species in the Greek sector, totaling 204 vascular plants, reflecting the compact basin's role in harboring Balkan-Mediterranean floral elements amid eight vegetational belts from lakeside reeds to montane grasslands.[49][50]Wildlife Populations and Endemism
Lake Prespa and its associated wetlands support over 260 bird species, representing a significant portion of the regional avifauna, with the area functioning as a key breeding and migratory site for approximately 50% of waterbirds in the Balkans. The Lesser Prespa Lake hosts the world's largest breeding colony of Dalmatian pelicans (Pelecanus crispus), with nesting pairs increasing from around 200 in 1991 to approximately 1,400 in 2017–2021, though recent counts indicate fluctuations due to factors like avian influenza outbreaks that caused mass mortality events in 2022. Great white pelicans (Pelecanus onocrotalus) also breed here, with pairs rising from about 50 in 1991 to over 1,000 by the 2010s, underscoring the lakes' role as a critical stopover and nesting ground along migration routes.[51][52][53] The fish community comprises 23 species, of which nine are endemic to the Prespa basin, including the Prespa barbel (Barbus prespensis), Prespa trout (Salmo peristericus, classified as endangered), Prespa roach (Rutilus albus), and Prespa bleak (Alburnoides prespensis). These endemics, adapted to the lake's oligotrophic conditions, face competition from introduced non-native species such as common carp and pikeperch, which have altered community abundances since their introductions in the mid-20th century. Empirical monitoring reveals dominance by native species like Prespa roach in catches, but declining trends for endemics like the Prespa trout due to hybridization and overfishing pressures.[54][55][56] Mammalian fauna includes 61 species, many inhabiting the encircling mountains, such as gray wolves (Canis lupus) and brown bears (Ursus arctos), though population estimates remain sparse and tied to broader Balkan trends rather than lake-specific censuses. Reptilian diversity encompasses 22 species, including the European pond turtle (Emys orbicularis), with surveys indicating higher abundances in modified habitats like farmlands compared to wetlands, reflecting opportunistic space utilization patterns. Amphibians number 11 species, contributing to the overall vertebrate richness without notable endemism beyond the regional scale.[57][58][5]Protected Areas and Conservation Initiatives
The Prespa basin is protected by three Ramsar wetland sites of international importance, designated to safeguard its unique aquatic and riparian ecosystems. These include Lake Mikri Prespa in Greece (Site No. 60, designated 1975), Lake Prespa in North Macedonia (Site No. 726, designated 1995), and the Albanian Prespa Lakes (Site No. 2151, designated 2013), collectively covering the lake's transboundary extent and supporting biodiversity conservation through regulated activities such as sustainable fishing and habitat monitoring.[59][60][61] National-level protections further bolster these efforts, with Prespa National Park in Albania established in 2017 spanning approximately 57,000 hectares along the lake's southeastern shore, encompassing diverse habitats from wetlands to oak forests and facilitating ranger patrols and visitor education programs. In Greece, the Prespa National Park, covering 327 square kilometers since 2000, integrates the Mikri Prespa lagoon and surrounding uplands, achieving measurable outcomes such as the restoration of over 1,000 hectares of reedbeds by 2020 through targeted habitat management. North Macedonia designates key areas like the Ezerani Strict Nature Reserve (established 1996, 120 hectares) adjacent to the lake, which has supported population recovery of endemic species via enforced no-hunting zones and annual ecological assessments.[62] The Ohrid-Prespa Transboundary Biosphere Reserve, recognized by UNESCO's Man and the Biosphere Programme in 2014 and expanded in subsequent phases, spans 446,244 hectares across Albania and North Macedonia with collaborative extensions into Greece, promoting integrated land-use planning that has resulted in over 50 joint monitoring initiatives by 2020 to enhance cross-border habitat connectivity. Complementing this, the Prespa Ohrid Nature Trust (PONT), founded in 2015, has disbursed grants exceeding €5 million since 2017, including post-2020 allocations for protected area management effectiveness, such as equipment upgrades and staff training that improved patrol coverage by 30% in recipient sites across the three countries.[63] UNDP-supported watershed management plans, initiated in the late 2000s and updated through projects like the GEF Prespa Regional Initiative, have built local capacities via training over 200 stakeholders in ecosystem-based planning, leading to the delineation of 15 groundwater bodies and implementation of monitoring protocols that track water quality indicators annually for adaptive conservation. These initiatives have collectively advanced metrics such as increased habitat coverage under active management, reaching 70% of the basin by 2023, without compromising traditional uses.[64]Transboundary Administration
Bilateral and Trilateral Agreements
The trilateral Declaration on the Creation of the Prespa Park, signed on February 2, 2000, by the prime ministers of Albania, Greece, and the Republic of Macedonia alongside the European Commissioner for the Environment, established the Prespa basin as a shared protected area to coordinate environmental protection and sustainable development amid prior uncoordinated resource uses.[65] This EU-facilitated framework emphasized joint preservation of the lake's biodiversity, water resources, and cultural heritage through collaborative monitoring and policy alignment.[66] The International Agreement on the Protection and Sustainable Development of the Prespa Park Area, concluded on February 2, 2010, by Albania, Greece, North Macedonia, and the European Union, formalized binding provisions for ecosystem conservation, including integrated water management, habitat restoration, and restrictions on unsustainable exploitation.[67] Ratified by the EU Council on October 4, 2011, the pact mandates trilateral commissions for decision-making on transboundary issues like pollution control and species migration, drawing on EU Water Framework Directive principles for empirical data-sharing.[68] [69] Complementing the 2010 agreement, the Strategic Action Programme for the Prespa Lakes Basin outlines prioritized interventions for trilateral governance, such as basin-wide hydrological assessments and biodiversity inventories, to mitigate risks from fragmented national policies.[70] From 2021 to 2024, the Biodiversity Conservation in Transboundary Prespa project, funded by the Prespa Ohrid Nature Trust, advanced these frameworks through cross-border habitat mapping and endemism monitoring, extending the 2000 declaration's cooperative ethos with targeted grants totaling over €1 million for joint field surveys.[71] [72]Governance Structures and Cooperative Mechanisms
The Prespa Park Agreement, signed on February 2, 2010, by Albania, Greece, and North Macedonia, established formal transboundary governance through the Prespa Park Management Committee (PPMC), comprising representatives from national governments, local authorities, and non-governmental organizations to oversee integrated ecosystem protection and sustainable development.[73] The PPMC replaced the provisional Prespa Park Coordination Committee formed in 2000, providing a structured forum for joint decision-making on park management, with operational support from a dedicated secretariat and specialized working groups focused on monitoring, enforcement, and financing.[74] This institutional framework emphasizes contractual obligations over informal declarations, enabling regular high-level consultations among riparian states to resolve disputes and coordinate policies.[75] Cooperative mechanisms include data-sharing protocols integrated with the Drin River Basin management framework, facilitating exchange of hydrological and water quality information across borders to inform unified basin-level strategies.[76] Joint monitoring initiatives, such as cross-border water quality assessments initiated through technical meetings—like the October 2019 gathering in Stenje, North Macedonia—have operationalized shared surveillance of lake conditions via coordinated sampling and reporting protocols, supported by national hydrological stations linked through bilateral capacities.[77] Capacity-building efforts, including training programs and project funding under frameworks like the EU's Integrated Ecosystem Management in the Prespa Lakes Basin, have strengthened local implementation by enhancing technical expertise among stakeholders, evidenced by sustained reductions in border-related enforcement conflicts post-2010 through formalized dispute resolution channels.[78] These processes prioritize empirical monitoring data over political declarations, with the PPMC's consensus-based decisions ensuring accountability amid varying national priorities.Environmental Pressures and Debates
Water Level Fluctuations and Causal Factors
Lake Prespa has exhibited significant water level declines over the past seven decades, with an overall drop of approximately 10 meters since the mid-20th century peaks, reducing the elevation from around 851.83 meters above sea level in 1964 to a record low of 841.66 meters in July 2024.[8] This long-term trend includes a 7.79-meter decline between 1951 and 2000, alongside more recent accelerations such as a 54-centimeter drop in the four months preceding October 2024.[8][79] These changes have led to a 6.9% reduction in surface area (from 273.38 km² to 254.51 km² between 1984 and 2020) and an estimated 54% loss in volume, equivalent to over 2,000 hm³.[20] The primary natural causal factors involve imbalances in inflows and outflows, with precipitation deficits playing a key role; annual rainfall has trended downward at -3.16 mm per year from 1951 to 2000, limiting direct precipitation and river contributions that historically comprised about 45% of inflows.[8] Evaporation, heightened by rising temperatures and the lake's exposure to summer aridity, accounts for roughly 222.6 million m³ annually, amplifying net losses during dry periods when inflows are minimal.[8] Karst drainage represents the dominant outflow pathway, channeling approximately 50% of the lake's water (248 million m³ per year) underground toward Lake Ohrid via aquifers in the Galicica massif; this process exhibits historical sensitivity to seasonal aridity, as reduced surface inflows during summers increase reliance on karst-mediated groundwater flows.[8] Anthropogenic extractions for irrigation constitute a quantifiable additional outflow, estimated at 10–13 million m³ annually across the transboundary basin, with some analyses attributing up to 72% of recent declines to such abstractions amid hydrogeological modifications like earthquake-induced enhancements to karst permeability.[8][20] Isotope studies, including tritium and stable isotope analyses of springs, confirm these dynamics by revealing that 42–54% of downstream spring waters (e.g., at St. Naum and Tushemisht) originate from Prespa Lake, underscoring the karst system's role while isolating abstraction impacts through residence time estimates of 6 years for the underlying aquifer reservoir (3.7 × 10⁹ m³).[8] Data from 2020–2025 indicate losses exceeding historical natural variability, with an annual negative balance of 53 million m³ driven by compounded precipitation shortfalls and extraction pressures.[8][20]Pollution Sources and Eutrophication Risks
Agricultural runoff from intensive fruit orchards and arable fields constitutes a primary source of pollution in Lake Prespa, delivering excess nutrients such as nitrogen and phosphorus alongside pesticides and fungicides into the lake via surface and subsurface flows. In the Prespa basin, apple cultivation and other crops rely heavily on artificial fertilizers, with annual inputs estimated at 2,600 tons of nitrogen and phosphorus equivalents in North Macedonia alone, much of which enters waterways untreated.[80] Pesticide applications, including herbicides and insecticides, further contaminate sediments and water columns, as documented in assessments linking agricultural practices directly to detectable residues in tributaries.[81][82] These nutrient loads drive eutrophication, shifting the lake's trophic state toward hyper-eutrophic conditions, particularly evident in Mikri Prespa where total phosphorus averages 123 µg/L and dissolved inorganic nitrogen reaches 319 mg/L, correlating with chlorophyll-a levels of 10.76 mg/m³ indicative of algal proliferation.[83] Cyanobacterial blooms, often toxin-producing, persist from spring through autumn in Mikri Prespa, depleting dissolved oxygen and fostering anoxic zones at depths beyond 15 meters during summer stratification.[83][81] Macro Prespa exhibits transitional eutrophication, with total phosphorus varying from 31 to 877 µg/L and declining Secchi disk transparency signaling accelerated primary production tied to fertilizer-derived inputs rather than volumetric changes.[80] Irrigation return flows from agricultural fields amplify these risks by concentrating nutrients in drainage waters that discharge into the lake, as recent monitoring confirms anthropogenic dominance in total nitrogen and phosphorus elevations across basin tributaries.[81] Wetland margins, critical for natural filtration, face degradation from encroaching cultivation and nutrient overload, reducing their capacity to buffer eutrophication while promoting siltation and biodiversity loss in riparian zones.[83] Empirical data from 2024 basin-wide assessments underscore that land-use intensification, not climatic variability alone, causally links these inputs to observed trophic shifts and bloom events.[81]Conflicting Stakeholder Interests
Local fishing communities in Albania, Greece, and North Macedonia depend on Lake Prespa's endemic species, such as the Prespa barbell (Barbus prespensis) and Prespa trout (Salmo perleticus), for their livelihoods, yet unsustainable practices including illegal cross-border fishing and prohibited gear use have raised alarms about overexploitation. Conservation advocates, including park authorities, push for measures like multi-year spawning season bans—six years for barbell and three for trout in tributaries—to restore stocks, but fishermen contend these restrictions intensify poverty without sufficient compensation or alternative income sources, leading to resistance against enforcement by park staff.[84][85] Additional friction arises from great cormorant (Phalacrocorax carbo) predation, with birds consuming over 99% Prespa bleak (Alburnus prespensis) in their diet, prompting fishermen to blame colony growth—such as the one on Golem Grad island—for exacerbating stock declines alongside human harvesting, though conservationists prioritize protecting the birds as part of the ecosystem and note human overfishing as the primary driver. Recreational angling further competes with commercial fisheries, altering lake trophic structures and fueling debates over harvest quotas. Fishermen view cormorant management or culling as necessary for viability, while protected area managers emphasize sustainable human practices over predator control.[84] Agricultural stakeholders extract water for irrigation—contributing to documented lake level drops of up to 10 meters from 1950 to 2009 alongside reduced precipitation—clashing with conservation calls for abstraction limits to safeguard wetlands and aquatic habitats. Farmers argue that bans or reductions threaten crop yields in surrounding rural areas, where poverty affects over 24,000 basin residents, and criticize over-regulation as prioritizing international biodiversity goals over local development, such as refused land allocations for sustainable uses like medicinal plants. Transboundary differences in policy enforcement exacerbate tensions, with stakeholders in one country attributing pollution from agrochemicals or untreated sewage to lax upstream practices in others, hindering coordinated responses.[20][85][70]Socioeconomic Roles
Fisheries, Agriculture, and Resource Extraction
Commercial fisheries in Lake Prespa target both endemic and introduced fish species, including the Prespa barbel (Barbus prespensis), an endemic cyprinid that supports local catches alongside species like Prespa roach (Leucos basak) and Prespa bleak.[86][87] Fishing occurs across Albania, Greece, and North Macedonia using traditional methods such as gillnets and traps, with allowable catches estimated at around 450 metric tons annually basin-wide, though actual landings remain lower, for instance approximately 80 tons in Albania.[88][89] Post-World War II, fishing infrastructure expanded modestly, but the number of active fishermen has steadily declined since 1945, with Greece reporting a drop from 190 commercial fishing families in 1939 to fewer today amid aging practitioners.[90][91] Empirical surveys from the 2010s indicate declining fish stocks attributable to over-extraction, evidenced by reduced catches per unit effort and dominance of smaller, introduced species in hauls from the Greek portions of Megali and Mikri Prespa lakes.[92][80] In North Macedonia and Albania, similar trends show numerical dominance by a few species like roach and bleak, signaling sustainability challenges for endemics targeted commercially.[87] Agriculture relies on lake water for irrigation, particularly for fruit orchards such as apples in the North Macedonian basin, where expanded cultivation has increased water abstraction to support yields but contributes to basin-wide resource strain.[93][6] No significant mineral or other extraction occurs, with economic dependence centered on these fisheries and irrigated farming.[88]