A State of the Environment Report - LakeNet - World … of Env. Report Mar03.pdfThe common problems...

LAKE OHRID AND ITS WATERSHED:OUR LAKE, OUR FUTURE

A State of the Environment Report

Dr. Mary C. Watzin, Rubenstein Ecosystem Science Laboratory,University of Vermont, Burlington, Vermont, USA

Erika Swahn, Rubenstein Ecosystem Science Laboratory, Universityof Vermont, Burlington, Vermont, USA

Mary Watzin, Andreas Matzinger, Zoran Spirkovski, Vasa Mitic,Raimonda Totoni, and Elizabeta Veljanoska-Serfiloska

January 2003

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...WITH COMMON PROBLEMSBecause of its high biodiversity and its unique cultural heritage, Lake Ohrid is a lake of tremendous local and

international significance. But many forces also threaten it. Since the end of World War II the population in the lake’swatershed has grown rapidly. It now approaches 200,000 permanent residents, with many thousands more cominginto the basin during the summer touristseason.

Population growth anddevelopment have impacted the lakein many ways. These include intensefishing pressures, destruction of thereed beds and other natural habitatsaround the shoreline of the lake, andthe introduction of pollutants, especiallyphosphorus, into the lake water.Phosphorus is fertilizing the lake,stimulating algae growth that threatensthe lake’s unique biodiversity and thecrystal clear water that is its majortourist attraction.

A UNIQUE LAKE...Lake Ohrid is very old. It was formed 2-3 million years ago by earthquakes that fractured the landscape and

created its deep bowl. Because the lake is so old and the surrounding hills and mountains isolated it from other waters,a unique collection of plants and animals have evolved here. Some of these plants and animals were common millionsof years ago, but have virtually disappeared from other places in the world. Scientists call these species “relicts” or

living fossils. Other species live only in LakeOhrid and are found nowhere else on theplanet. These “endemic” species includethe famous Lake Ohrid trout and manyother fish, snails, worms, sponges andaquatic plants. Almost 70 % of LakeOhrid’s plants and animals are relic orendemic species.

People too have made the Lake Ohridwatershed their home for thousands ofyears. The ancient Illyrians built villages inthe Ohrid-Prespa region in the 4th and 5th

centuries BC. The castle northwest ofPogradec was constructed during this time.In the first century AD, the town of Ohridwas the cultural center of Macedonia. Inmedieval times, the famous missionaries,St. Clement and St. Naum, made Ohrid

their home and a thriving university, the oldest in Europe, educated over 3500 students. In the 10th century, Samuelruled over the greater Slavonic region from the fortress on the hill of Ohrid. Today the Lake Ohrid watershedincludes three countries, Albania, Macedonia, and Greece, and numerous cities, towns and villages.

A view of Lake Ohrid from Samuel’s fortress.

Runoff from agricultural fields is a significant source of pollution inboth Lake Prespa and Lake Ohrid.

State of the Environment 1

The common problems of Lake Ohrid encouraged the governments of Albania and Macedonia to cometogether and sign an agreement on 20 November 1996 to begin the Lake Ohrid Conservation Project. Fundingfor the project comes from a Global Environment Facility (GEF) grant through the World Bank. The activities ofthe Lake Ohrid Conservation Project began in 1998 and will continue until mid 2003.

Four Components of the Lake Ohrid Conservation Project

Component A: Institutional Strengthening Focuses on increasing the capacity of public officials in the Lake Ohrid watershed to enforce each country’s

environmental laws, regulations, standards and policies.

Component B: MonitoringFocuses on establishing a comprehensive bi-national monitoring program to inform the public and local

officials about the condition of the lake and to provide the information necessary for effective decision-making.

Component C: Participatory Watershed ManagementAims to mobilize groups within the watershed to create a strategic action plan.

Component D: Public Awareness and ParticipationWorks to create public awareness and increase community participation to ensure effective and sustainable

implementation of the Lake Ohrid Conservation Project.

The objective of the Lake Ohrid Conservation Project is to conserveand protect the natural resources and biodiversity of Lake Ohrid bydeveloping and supporting effective cooperation between Albania andMacedonia for the joint environmental management of the watershed.

THE LAKE OHRIDCONSERVATION PROJECT

2 State of the Environment

There are critical choices to be made – the future of the Lake Ohrid basindepends on the choices that we all make in the coming years.

This State of the Environment Report summarizes the information about the watershed that has beengathered and highlights the environmental problems that currently exist. It also outlines some of the stepsthat must be taken in the future, by both governments and the citizens of the basin, to begin solving theseproblems.

THE WATERSHED

Lake Ohrid has 87.5km of shoreline andcovers an area of 358.2km2. Although theaverage depth of the lakeis 164 m, it has amaximum depth of 289m. The water that fillsLake Ohrid comes fromits watershed, or drainagearea. The rivers andstreams that run downfrom the mountainsidesand out of the valleys intothe lake, such as theCerava River and theKoselska River, deliverabout half of its water.The rest comes from thesprings that flow into thesouthern part of the lake,at St. Naum, Drilon andTushemisht. Thesesprings are fed by waterflowing out of the porous mountains to theeast, Galicica and Mali i Thate. These mountainsare made of karst, a kind of rock that is easilyeroded by water. Over thousands of years,holes and channels have formed within themountain rock. These channels carry water thatoriginated in Lake Prespa to Lake Ohrid.Because Lake Prespa sits 150 m above Lake

The springs at St. Naum carry water from Lake Prespa into Lake Ohrid.

Ohrid, its waters run “downhill” to Lake Ohrid through the channelsin the karst. One of the easiest places to see the water leaving LakePrespa and entering the underground mountain channels is at the Zaveriswallow hole, along the western shore of Big Prespa Lake, near thevillages of Gollomboch and Gorica.

Like Lake Ohrid, Big and Small Prespa Lakes also get their waterfrom their watershed. These lakes have smaller drainage areas andthey are filled mostly by the rivers flowing into them. About every 11

years, all the water in Lake Prespa isreplaced by new water. In contrast,it takes about 70 years for all thewater in Lake Ohrid to be replaced.Water flows out of Lake Ohrid nearStruga, into the Black Drim River.This river eventually runs all the wayto the sea.

Left: Mount Galicica towersabove Lake Ohrid in Macedonia.

Next Page: The Lake Ohridwatershed (in deeper colors)includes parts of Albania,Macedonia and Greece.


LAKE OHRIDCONSERVATION PROJECT


HUMAN ACTIVITIES IN THE BASIN – STRESSES ON THEECOSYSTEM

way into Lake Ohrid. This situation poses athreat to the health of both the inhabitants andthe tourists in Pogradec.

In Macedonia, the Regional SewerageSystem for the Protection of Lake Ohridcollects wastewater from about 65% of theOhrid-Struga region and delivers it to thetreatment plant Vranista. After treatment, thewastewater is discharged into the River BlackDrim. The first phase of the plant wascompleted between 1985 and 1987 and it hasbeen operating since June 1988. The plant hasthe capacity to treat the wastes produced byabout 120,000 people. A general developmentplan for the regional sewerage system through2025 was made in 2001. In two additionalconstruction phases, an additional 44 km ofsewer, which will treat most of the shoreline

on the Macedonianside of the lake, will beadded to the system.

In the Lake Presparegion, only the townof Resen has asewerage collection andtreatment facility. Thewastewater treatmentplant Ezerani has thecapacity to treat thewastes of about 12,000residents and servesabout 80% of thetown.

There are about 106,000 residents in the Macedonian part of the watershed and about 61,000 residents on theAlbanian side of the watershed. This population is 5 or 6 times as large as it was at the end of World War II. Mostresidents live in several large towns – Ohrid, Struga, and Resen in Macedonia and Pogradec in Albania, but there arealso many small villages and communities scattered throughout the watershed.

WastewaterWhile people are a natural part of

ecosystems, some of our activities can haveharmful effects on other species, especially whenwe live in dense settlements. In many townsand cities, human waste is discharged intostreams or the lake. Human waste containsnutrients that act as fertilizers and harmfulbacteria that can pollute streams and lakes. Thedetergents we use to wash our clothes alsocontain high concentrations of nutrients.

Human waste and wastewater is nottreated in Albania. In Pogradec, the wastegenerated by about 30% of the town iscollected but it is simply discharged into LakeOhrid near Tushemisht. Because Pogradec hasbeen growing, the volume of wastewater isalso increasing, and currently, the wastewaterproduced by over 60,000 residents makes its

The sewer line isextended in thetown of Ohrid.


AgricultureFarmland can also be an important source

of pollution to Lake Prespa and Lake Ohrid.Fertilizers, soil particles, and pesticides washinto rivers and streams and eventually to thelakes. Much of the farmland in the watershedis irrigated, and the excess water, carryingsediments, fertilizers and pesticides, also drainsback to the lake. In both Albania andMacedonia, fertilizer and pesticide use issubstantial, including pesticides that can behighly toxic to both people and the plants andanimals living in the lake.

Around Big Prespa Lake, agriculture is aparticular problem. The fields are widespread,the lake level is dropping, and the cultivatedland extends right down to the edge of the

to the landfill Kafasan.This landfill is situated12 km southwest ofStruga, near the villageMali Vlaj. Waste fromthe town of Resen, andin the summer monthsfrom the tourist resortsof Asamati andPretor, is collected andtaken to the landfillAlcevski Koshari,about 3 km north oftown. None of theselandfills is lined or hasa drainage system tocollect and treat thecontaminated wastes.

Pesticides used on apple trees may end up in the fish in Lake Ohrid.

The River Velgoskais littered with solidwaste.

IndustryIndustry also contributes pollution to the

lake in many forms. In Pogradec, the metalparts factories and a phosphate detergent plantdischarge wastes to the lake without treatment.To the east of Pogradec, there are a numberof old mines that used to produce chromium,nickel, iron, and coal. Only one of theseremains in operation, but the mining sites stillhave many large piles of waste material thatis exposed to the rain. Rainfall washespollutants from the piles into the lake.

Industries in Macedonia include automobilespare parts, electrical parts, and textile, ceramic,and metal processing plants and foodproduction. All of these industries producewaste that may be contaminating the Sateska,Velgoska, Koselska, and Golema Rivers. Foodprocessing plants that discharge waste such asapple pulp are a significant problem in the Prespawatershed.

Solid WasteSolid wastes can be a source of

contamination to the lake if they are notdisposed of properly. As this waste materialbreaks down, highly contaminated liquids canseep down into the underground water andadjacent streams and make its way to the lake.

In Pogradec, waste is collected anddeposited at a site in the valley near Gurras,along both sides of the road leading to theformer coal mine of Alarup. This dump hasno provisions to treat the waste or keep itfrom contaminating the groundwater. Aproposal has been developed to construct alandfill, Cerava-1, at a site about 15 km fromPogradec, but not all experts agree that this siteis appropriate.

In Ohrid, waste is collected and taken tothe landfill Bukovo, about 25 km outside oftown. In Struga, waste is collected and taken

lake. Fortunately, pesticides are not usedextensively around much of Big Prespa Lake.


TourismTourism can be considered a special kind

of “industry.” A healthy tourist industryrequires hotels, restaurants, and otherappropriate services for the tourists. Becausethe tourists come to experience the water,many of these developments are right alongthe shoreline. The tourists also produce wastesthat must be treated and disposed of properly.

Both the Macedonianand Albanian shorelines aretourist destinations, and bothhave suffered from thepolitical instability in the widerBalkan region since 1991. InOhrid, the number offoreign tourist overnight stays

has been reduced up to 70%. As the politicalsituation improves, Ohrid is uniquelypositioned to appeal to the growing market incultural tourism, with the many historic sites,monasteries, and other national treasures in thearea. Lake Ohrid could also be promotedwithin the ecotourism market, but an essentialprerequisite for this kind of tourism is a healthyand unpolluted environment, with clean water.

A warm, sunnyday and coolclear water drawa crowd alongthe shores atKaneo.

Shoreline communities in Albania have grown dramatically inthe last 10 years.

SocioeconomicsPressures on the environment are greatest

when socioeconomic conditions are difficultand unemployment rates arehigh. Under thesecircumstances, resources areoften not available forenvironmental protectionand improvement. Currently,the unemployment rates inboth Albania andMacedonia are high. Manypeople of working age donot have full time jobs withbenefits. There are manycauses for this situation, butas the political transitioncontinues, solving thisproblem is central to healthycommunities and healthyenvironments.


THE ECOLOGY OF LAKE OHRID

So many plants may grow in the lake thatthe fish and other animals in the lake can’t eatthem all. When the uneaten plants die, they sinkto the bottom and decompose, with the helpof bacteria. This decomposition uses upoxygen, sometimes so much that there is notenough oxygen left for the fishes and other livingthings in the lake. The decomposition of otherorganic matter coming into the lake in runoffand waste discharges also uses up oxygen. Ifthese animals can’t move away, or the zone oflow oxygen is very widespread, the animals willdie. You may have seen this as a “fish kill” inthe lake.

Even if the animals don’t die from oxygenstarvation, fertilization will affect them. Theplants in Lake Ohrid are the base of the foodweb. The kinds of tiny animals that eat theseplants will also change as their diet is alteredand the changes are passed on to each new levelin the food web, all the way up to the fishes,birds, and wildlife. Very small increases in

In lakes, there are three main groups ofplants, tiny floating cells called phytoplankton,slippery algae that grows on the tops of rocksand stones, and the rooted reeds andsubmerged plants growing in the shallowwater muds and sands. If you have a garden,you know that adding fertilizer will make plantsgrow. It is the same in lakes. The fertilizer weare adding to Lake Ohrid and Lake Prespa isthe phosphorus in detergents and in humanand animal waste, in runoff from the land,and in the rivers and streams draining into thelakes. This phosphorus is stimulating plantgrowth, and as a result, the water in the lakesis becoming greener. Some plants are betterable to take advantage of the extraphosphorus and these plants are thriving, evenoutcompeting the other plants.

Fuzzy green algae grows on the surface of these rocks.

A microscopic view of the tiny phytoplanktonin Lake Ohrid.

Reeds thrive along undeveloped shorelines.


nutrient concentration can result in dramaticchanges in species composition in the lake. It ispossible that in the coming years, thecommunity of plants and animals in the lakesmay be very different than the one that ispresent today because each successive link inthe food web is faced with a different foodenvironment. Lakes that have lots of nutrientstend to have a much lower diversity of speciesbecause only very tolerant species can survivein the nutrient-rich environment.

We call all these changes that start withnutrient enrichment “eutrophication.”Eutrophic lakes have lots of plant growth andare frequently characterized by cloudy or greenwater. All lakes become more eutrophic overthe centuries as rivers and streams deliver

II. Considering the very large volume of waterin Lake Ohrid, this is a very significant change.If this trend is verified by additionalmonitoring, Lake Ohrid can be expected tochange dramatically in the next few decades.

One of the largest single sources ofphosphorus is the untreated sewerage fromthe town of Pogradec. Runoff from pasturesand agricultural land is another big source.Some of the rivers and streams that dischargeinto Lake Ohrid and Lake Prespa are a thirdbig source, and scientists have been measuringthe amount of phosphorus in these streamsfor the last few years. An estimate of the totalamount, or load of phosphorus to the lake iscritical in order to predict its future condition.Preliminary estimates suggest that this load maybe 3-5 times greater than it should be to keepLake Ohrid in a clear water state.

On the Albanian side, the water in theCerava and Pogradec Rivers and in DrilonSprings carries the highest loads ofphosphorus. On the Macedonian side, theRivers Velgoska, Koselska, and Sateska are themost polluted and deliver the mostphosphorus to Lake Ohrid. The River Velgoskaflows through the northern part of the city ofOhrid and carries both municipal andindustrial waste. The River Koselska flowsthrough a predominantly rural area, but it alsoreceives some municipal and industrialwastewater. The River Sateska, which wasdiverted into Lake Ohrid in 1962, flows

PhosphorusScientists in both Albania and Macedonia

have been tracking these changes, starting bymeasuring the concentration of phosphorusin the lakes. The concentration of phosphorusin Lake Prespa shows that this lake is alreadyeutrophic. The concentration of phosphorusin the middle of Lake Ohrid is still low enoughfor this lake to be considered “oligotrophic,”but the amount has been increasing over time.The concentration now may be 3 or 4 timesthe concentration measured before World War

sediments and nutrients to them and the lakesgradually fill in. This aging is a natural process,but when people add to the nutrients with theiruntreated wastes and by using the land in waysthat wash nutrients and soils into the water,this process speeds up.

Historically, Lake Ohrid has been knownas an “oligotrophic” or clear water lake.Because Lake Prespa is a shallow lake, it isnaturally a little more eutrophic than Lake Ohrid.Scientists think that Lake Ohrid may have“aged” by thousands of years in just the lastfew decades because of the actions of people.Lake Prespa is becoming highly eutrophic andsuffers from cloudy, green water and lowoxygen concentrations in the summer.

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The CeravaRiver carriesphosphorus andother pollutantsinto Lake Ohrid.


through both agricultural and urban areas andcarries a very high load of both phosphorusand sediment, which is deposited in shallowwaters of Lake Ohrid at the mouth of theriver. The load of phosphorus coming fromthe Sateska River may be about the same asthat coming from the sewerage of Pogradec.

The springs at Saint Naum, like DrilonSprings, carry water from Lake Prespa intoLake Ohrid. Very few measurements havebeen made of this spring water, but thesemeasurements show that the concentration ofphosphorus is elevated.

stratification because the wind can completelymix the warmer surface water down into thelake. Only in spring and summer can the watersbecome somewhat stratified. During thisperiod, the oxygen concentration decreasesdramatically. In fact, in summer, the dissolvedoxygen concentration can drop to near zero atthe bottom of the lake because there is so muchdecomposing plant material in the water. Bymid-fall, oxygen concentrations have generallyrecovered to levels found at the surface.

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Dissolved oxygenTo understand oxygen in Lake Ohrid and

Lake Prespa fully, you also need to understandtemperature. Lake Ohrid is a very large lake,so the sun warms the water in it slowly. In thespring and summer, water at the surfacebecomes noticeably warmer, but because thelake is so deep, the sun cannot warm all thewater down below. Therefore, layers of waterof different temperatures form in the lake.The water near the surface, in a layer calledthe epilimnion, is warmest. It actually floatson top of the coldest water down below, ina layer called the hypoliminion. The transitionzone between these two layers is called themetaliminion. This layering of the water iscalled stratification.

Oxygen can dissolve into the lake waterin the epilimnion from the air. The tinyphytoplankton that are photosynthesizingand growing in the upper layers of the lakealso put oxygen into the water. But thehypolimnion has no opportunity to gainoxygen from the air. As oxygen is used bythe animals in these deeper waters and bythe bacteria decomposing the dead plantsand animals that sink down into the water,oxygen concentrations can drop substantially.

In the fall, when air temperaturesdecrease, the surface waters cool off andthe layers can mix. Once every 6 or 7 years,when there is a very cold and windy winter,the layers of water totally mix and oxygenis carried down from the surface to replenishthe deeper layers of Lake Ohrid.

Lake Prespa is much shallower than LakeOhrid. It does not show such strong

The rivers in the Prespa basin, includingGolema, Brajcinska, and Kranska, carry veryhigh phosphorus loads. In the summer, theoxygen concentration in these waters can alsobe very low. The high nutrient concentrations inthe Prespa tributaries reflect the surroundingagricultural watershed. Fertilizers and animalwaste regularly wash off the fields and pastureswith rain water and irrigation and enter thestreams and the lake. This is why Lake Prespa isso eutrophic. Because Lake Prespa is the sourcefor the water in the St. Naum and Drilon springs,it is likely that much of this phosphoruseventually makes its way to Lake Ohrid.

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In February 1999 (blue line), the temperature of the water in themiddle of Lake Ohrid is nearly the same from the surface to the bottom.But by May (yellow line), the water at the surface has been warmed bythe sun. In July (red line), the surface waters are nearly 15o warmerthan the deeper water. The following January (green line) coldweather has again created uniform temperatures from top to bottom.


The waters inmuch of LakePrespa are greenwith phytoplanktonin the summer.These tiny floatingplants areresponding to thephosphorus bymultiplying rapidly.Submerged plants,or weeds also growthick in the nearshorezone. This situationwill not change untilthe phosphorusinputs to the lake arer e d u c e dsubstantially.

The near shore waters of Lake Ohridadjacent to Pogradec and Tushemisht also showobvious phytoplankton and aquatic weedgrowth in the summer. In fact, in many nearshore locations on both the Albanian andMacedonian sides of the lake, the aquatic plantshave been responding to the fertilization byphosphorus. In the last several years, bothAlbanian and Macedonian scientists havedocumented a shift in the composition of theplants to favor those species that grow well ineutrophic conditions. Species that prefer moreoligotrophic conditions are becoming lessabundant. These changes provide furtherevidence that the Lake Ohrid ecosystem ischanging and underscore the need to reducethe phosphorus inputs to the lake.

Microsopic viewof Pandorina morum, aspecies of phytoplankton that thrives ineutrophic waters.

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Bacterial pollutionOne of the biggest potential risks to human

health for the communities living along LakeOhrid is contamination with disease-causingbacteria and viruses that enter the lake in humansewage. When these organisms are present,there is a significant risk of illness for peopledrinking the water or swimming in it. Bacteriaabundances are generally highest in the summerand after heavy rains. In exceptionally heavyrains, the capacity of the existing seweragesystems can be exceeded and additionaluntreated wastes are discharged to the lake.

In 1988, the first phase of the sewagecollection and treatment system was completedalong the shoreline in Ohrid Bay in Macedonia.

After this system began operating, there weredramatic improvements in the water quality inOhrid Bay. The number of harmful bacteriain the water decreased one thousand fold. Thewater in Ohrid Bay is now generally safe forboth drinking and swimming. Theseimprovements make a strong case forcontinuing to implement sewage treatmentsystems along the entire shoreline of the lake.

On the Albanian side of the lake, thehighest level of bacterial pollution occurs nearthe town of Pogradec, where raw sewerageflows directly into the lake. Large numbers ofharmful bacteria have been found up to 200m from the shoreline. In the years 1996 to 2000,Albanian scientists found an increase in theabundance of harmful bacteria in Lake Ohridwaters close to shore. This is probably becausethe population has been increasing in Pogradec.This situation will not improve until a seweragecollection and treatment facility is constructedfor the town. But once a system is completed,the improvement along the Pogradec shorelineshould be rapid, mirroring the improvementsfound in Ohrid Bay in the late 1980s.

Away from the major towns, bacteriapollution is most commonly found wherestreams and rivers discharge into the lake. Thesestreams carry human waste and animal wastefrom the inland villages to the lake. All of thesesources must be considered in order to keepLake Ohrid waters clean for everyone’s useand enjoyment.

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Millions of E. coli, a bacteria in human sewage, live in just a few drops ofwater near the shore of Pogradec in the summertime. The number ofbacteria decline away from the shoreline, but even at 200 m, a few dropsof water can hold thousands of bacteria.


Metal pollution in Lake OhridIn addition to eutrophication, Lake Ohrid

also shows metal pollution near the sites ofthe old chromium, iron, nickel and coal minesoutside Pogradec. The preliminary samplesthat Albanian scientists have collected at theGuri i Kuq mine show concentrations ofmetals in the near shore lake water that arevery high. It is likely that the muds and sandsin these near shore locations are alsocontaminated, and this may pose a risk to theinvertebrates, fish and birds living in thissection of the lake. People who catch and eatfish in the area may also be at risk and it ispossible that local drinking water sources havebeen contaminated. Long-term exposure toelevated levels of chromium, copper, cobalt,nickel, and other metals have been shown tohave harmful effects on human health. As

scientists continue to gather data at these sites,they will be able to fully evaluate the risks topeople and to wildlife.

The Living Community of LakeOhrid

There are two unique communities ofplants and animals in Lake Ohrid, the nearshore, or littoral zone community, and theoffshore, or pelagic community in the deepwaters in the middle of the lake. Each of thesecommunities is characterized by differentgroups of organisms.

In the littoral zone, rooted plants growup from muddy and sandy bottoms andslippery algae grow on the surface of therocks and other hard surfaces. These plants(scientist call them macrophytes) often growin distinct zones or belts along theshoreline. In the deeper water (5-15m), algae and rooted aquatic plantsgrow like an underwater garden.Some have floating leaves at thesurface. Closer to shore, the reedsappear and grow right up to theedge of the water. In many places, aparticular kind of slimy algae calledCladophora grows on most surfaces.

In areas of the shoreline thatreceive river input, runoff fromagricultural land, or sewerage inputs,the littoral zone community can bethick with these aquatic plants. Thosespecies that like lots of phosphorusare choking out the other plants.

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Cladophora likes lots of phosphorus, and it thriveswhen runoff carries phosphorus into the lakein the summertime.

The reed zone is an especially importanthabitat for many other organisms and providesmany benefits for people. The reeds’ roots holdthe mud together and the stems slow the waves,reducing the erosion of the shoreline. The plantsalso remove some of the phosphorus and other

An abandoned mine along the south shore of Lake Ohrid in Albaniamay still be polluting lake waters.

Cladophora, a green algae, explodes after rainfall in Ohrid.


pollutants running into the water. They provideliving and hiding spaces for many species offish and water birds, and they are the spawninggrounds for fishes such as the bleak and carp.Fish and ducks like the reed zone because theplants help hide them from their predators.When the reeds die back in the wintertime, theyadd organic matter to the lake that feeds otherorganisms like snails and worms. These smallanimals are the food that the fish and waterfowleat. As development has occurred along theshoreline, people have cut or burned away thereeds. This practice threatens the fish andwildlife of the lake and must be controlled.

The bottom-dwelling animals in LakeOhrid are very unique. Many of these smallinvertebrates (animals without bones) arefound nowhere else but Lake Ohrid. For

example, Lake Ohrid is the only place wherethe rounded sponge Ochridospongia rotunda isfound. Its closest relatives are in Lake Baikal,another ancient lake in Russia that was formedby earthquakes. More than 85% of the snailsin Lake Ohrid are also unique to Lake Ohrid.

On rocky bottoms, small mussels are verycommon. They attach themselves to the rockswith sticky threads that they secrete. On sandybottoms, a diversity of worms, snails,crustaceans and other organisms live on andburrowed in the substrate. Scientists inMacedonia have discovered that thiscommunity of small organisms has changedsignificantly in areas where human pollutionhas entered the lake. The implications of thesechanges for the fish and wildlife that feed onthese organisms are not yet known.

Fishes in the shallow water include a varietyof minnows, as well as fishes sought by anglerslike bleak and carp. During spawning, many

other fishes come into the littoral zone,including the Lake Ohrid trout. These fishare a link between the shallow water habitatsand the deeper water.

In the deeper water, or pelagiccommunity, the tiny phytoplankton formthe base of the food web. Tiny floatinganimals called zooplankton eat these tinyplants. In turn, these small animals are eatenby the small fishes in the lake, whicheventually end up in the larger fishes like theLake Ohrid trout.

Scientists monitoring the lake inMacedonia have found that both thephytoplankton and zooplanktoncommunities in Lake Ohrid are changing.New species more characteristic of nutrientenriched conditions have been discovered,and the species composition in locationsclose to river inputs and near the towns andvillages is changing to one that is dominatedby more eutrophic species. These changesreflect the changes in water quality in thelake, and underscore the need to controlthe pollution coming into the lake.

The fish in Lake Ohrid are an importantpart of the economy of both Albania andMacedonia. There are six species that areregularly harvested by fishermen, includingthe famous Lake Ohrid trout, the smallerbelvica, the bleak, carp, eel, and roach. Over

Millions of bleak once schooled along the shoreline from Peshtani toOhrid in winter.


the last decade, between 200,000 and 300,000kg of fish have been taken from the lake eachyear. Data gathered by scientists in Macedoniasuggest that this level of harvest may be morethan the lake can sustain. The numbers of fisheson the wintering grounds and returning to thespawning grounds each year are decliningnoticeably. In decades past, large schools ofbleak wintered in Ohrid Bay, as well as in frontof Peshtani and Trpejca in the east andRadozda in the north. Today, bleak only winterin front of Trpejca and Radozda. The numberof nests of Lake Ohrid trout on the spawninggrounds on the Macedonian side of the lakehas also changed dramatically. The average sizeand number of the fish has decreased andthe gender balance is changing.

In addition to harvest pressures, the nativefish of Lake Ohrid are also threatened by theintroduction of non-native species into thelake. Rainbow trout represents a particularconcern because it may displace the nativetrout. Although this fish was first introducedin the 1970s, fish farms represent a currentthreat for new introductions.

There is also some preliminary evidencethat the pesticides used by farmers in thewatershed may threaten fish in the lake. Thesepesticides have been found in the tissues offish collected from the lake. Not only are thesepesticides harmful to the fish themselves, butthey also pose hazards to the people who eatthe fish, especially women of childbearing ageand small children.

The shoreline and watersheds of LakeOhrid and Lake Prespa also provide criticalhabitat for a great variety of wildlife. Theseinclude frogs, turtles, and birds that are directlydependent on the lake, and many inland speciesthat rely on the forests and plains. The coastalwetlands provide critical habitat for hundredsof thousands of wintering water birds,including rare and threatened species such asthe Dalmatian pelican, ferruginous duck, spottedeagle, and imperial eagle.

Habitat loss and fragmentation, and humandisturbance pose the biggest threats to thecontinued existence of these animals. Habitatrestoration efforts could help bring these speciesback to healthy population levels.

Shoreline habitat loss and degradation threaten the Dalmatianpelican and other water birds in the Lake Ohrid watershed.

Moonflowersgrace thismeadowlandnear LakePrespa.


much higher than elsewhere along the coastlineand both these tiny plants and the rooted aquaticplants in this region are dominated by pollution-tolerant species. Elsewhere, near Ohrid, Strugaand the tourist establishments on theMacedonian shore, eutrophic species are alsobeginning to dominate.

The solution of the problems in the littoralzone will take acoordinated andaggressive managementapproach that reducesthe pollutants cominginto the lake from bothsewerage and industrialdischarges and fromriver inputs and runofffrom the land. Thisapproach must alsoreverse the habitatdestruction where theland meets the water,especially in the reedzone. Areas that havenot been degradedshould receive specialprotection because these

areas are sustaining the remaining fish andwildlife populations in the lake.

The water in the area of Pogradecrepresents the single largest water qualitychallenge on the lake. Pollution from theuntreated human sewage flowing into the lakeis adding greatly to the eutrophicationproblem, and seriously threatening humanhealth through contamination by harmfulbacteria and viruses in the fecal material.

In 2001, the German government,through the Kreditanstalt fur Wiederaufbau(KfW) and the Swiss government throughStaatssekretariat fur Wirtschaft (SECO)provided funding to design and construct asewerage collection and treatment system forPogradec and the surrounding villages. The newsystem will collect wastes from households andbusinesses in Pogradec, Verdove, and Bucimas.Wastewater will be delivered to a new treatmentplant that will be constructed southwest ofTushemisht, near Bucimas. The treated waterwill then be discharged into the lake nearTushemisht.

MANAGEMENT CHALLENGES AND HOT SPOTSBecause the littoral zone receives the direct

impacts of the people living along the shoreline,it tends to be the most impacted environmentin most lakes. Lake Ohrid is no exception tothis pattern. The habitat destruction and waterquality impairment is most severe in the littoralzone, especially in those areas adjacent to thepopulation centers in both Macedonia andAlbania.

On both Lake Ohrid and Lake Prespa,the destruction of the reed zone has removedvaluable spawning, nesting, feeding and restinghabitat for fish and wildlife and is negativelyimpacting water quality. Practices, such asgrazing, cutting, and burning the reeds used tobe common around Little Prespa Lake and inmany areas on Lake Ohrid. In locations wherethe natural vegetation has been removed, soilcommonly washes into the lakes and isdeposited on the lake bottom. Although somelaws have been passed to protect the reedzones on the Macedonian side of the lake,population growth and socioeconomicpressures are leading to continued destructionof the reeds and other lake habitats. Theimportance of these environments for bothwildlife and human welfare is still not reflectedin economic planning and decision-making.

Evidence of the ecological impacts ofhuman activities is apparent in the aquatic plantcommunity and in the phytoplankton,zooplankton, and bottom invertebratecommunities in the near shore waters. NearPogradec, the phytoplankton densities are

Development hasdramaticallyreduced the reedzone along LakeOhrid.


The new sewagetreatment system will treat thewastewater of about 60% ofthis region. Construction willbegin in 2003 and becompleted by 2005. A possibleextension after 2010 wouldallow the treatment of all thewastewater produced in thePogradec area. If the newtreatment plant reduces thephosphorus content of theload it receives by 80% asdesigned, then when thetreatment plant comes on line,about 24% of the total annualphosphorus load to the lakewill be removed, a verysignificant amount.

In 1999, representatives ofthe Macedonian and Albanian governmentssigned a joint statement endorsing the plansfor the Pogradec wastewater treatmentproject. Although the Macedonian delegation(and the Hydrobiological Institute) would havepreferred that the wastewater be pumpedoutside of the Ohrid Basin, this option wasnot judged feasible in the first phase. Theparties agreed that if the necessaryimprovements in the water quality of LakeOhrid do not occur after the new system hascome on line, then both parties will join theirefforts to find additional funding for theconstruction of additional measures to takethe waste outside the catchment area.

In the future, scientists in both Albania andMacedonia will work together to collect the datato evaluate water quality and to determine howmuch phosphorus load the lake can handle andstill remain in an oligotrophic, or clear watercondition.

The six mines and one mineral enrichmentplant located near the shores of Lake Ohrid tothe east of Pogradec also present a managementchallenge. It is possible that the high levels ofmetal contamination at these sites are havingtoxic effects on the fish, birds and other aquatic

life in the areaand might posea risk to peoplewho live in thisarea bycontaminatingthe drinkingwater. A fullerevaluation ofthese risks andplans to containor remove thewaste must bepursued.

Mine waste along the shoreline exports metals to LakeOhrid each time it rains.

Soon, a new sewage treatment system will improvethe water quality near Pogradec.


The Sateska River presents a particularmanagement challenge for the littoral zone onthe Macedonian side of the lake. In 1962, theriver was diverted from its natural dischargeinto the Black Drim River into Lake Ohrid inorder to drain the Struga marshland andsupport hydroelectric power generation on theBlack Drim River. The diversion of the Sateskaalmost doubled the size of the Lake Ohridwatershed and greatly increased the phosphorus

and sediment loading to the lake.The impacts in the littoral zoneinclude substantial filling of the lakebottom and persistent problemswith nutrient enrichment and lowoxygen concentrations in the lakewater.

The Republic of Macedoniahas investigated rediversion of theSateska back into the Black DrimRiver and various measures to slowthe erosion of the riverbanks anddelivery of sediment to Lake Ohrid.Although it is currently unclear asto when or if a full rediversionproject might be implemented,some erosion control measuresusing reforestation are beingimplemented as part of the Lake

Ohrid Conservation Project. The restorationof the Sateska River and the adjacent littoralzone of Lake Ohrid remains an urgentmanagement priority.

The declining fish populations in LakeOhrid represent a final urgent managementpriority. Trout, carp and bleak have all sufferedfrom human impacts to their spawning andwintering grounds, but the human pressureson the trout population in Lake Ohrid seemto be most extreme probably because of thegreater demand and higher economic value of

this fish. Although the overall catchof trout has only declined slightlyin the last several years, there hasbeen a dramatic shift in the harvest.Beginning in 1992, the landings inAlbania increased dramatically,while those in Macedonia began tofall. The differences in fishingpressures in the two countries arethe results of differences in the socialand political situation and the fishingregulations in each country. Whilethere are limits on the catch inMacedonia through concessionsand licenses granted by thegovernment, there are norestrictions on the number of boatsallowed on the lake or the numberof nets a fisherman can employ inAlbania. The allowable net size inAlbania is also smaller than inMacedonia.

The Sateska River is choked with sediment that threatens the littoralzone in Lake Ohrid.

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1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 years MK AL

Although the harvest of fish from Lake Ohrid has remained high overthe last 30 years, recently the landings in Macedonia (blue line)have declined, while the landings in Albania have increased (greenline).


In Macedonia, the fishing industry ismanaged through five-year concessionsgranted by the government to fishingcompanies. A company that is granted aconcession must restock the lake through anapproved plan and must pay 10% of thewholesale value of the catch to thegovernment for the purposes of improvingthe fishing conditions on the lake.

In Albania, the fishing industry is in theprocess of being organized into fishingassociations by village. Associations will beformed in Pogradec, Lin, Hudenischt andTushemisht. The regulations that will governthese associations are still being developed.

Because overfishing seems to be themajor cause of the decline of the troutpopulation, controls on the number and sizeof fish must be implemented andcoordinated on both sides of the lake. Eachspecies of fish in the lake is one single, linkedpopulation and these populations must bemanaged holistically, with similar regulationsin both Macedonia and Albania.

Scientists are working to predict thenumber of fish that can be harvestedsustainably, without depleting the populationover time. Sustainable levels of harvest of allthe commercially valuable fish populations inLake Ohrid, including the trout, bleak and

carp, must be developed. Once these levels havebeen determined, then the harvest regulationsin both Albania and Macedonia must beharmonized to ensure that these levels areachieved. Vigorous enforcement of theappropriate regulations will also be necessary.Efforts that improve water quality and restorethe littoral zone and shoreline habitats will alsohave positive benefits for all the fish of LakeOhrid.

Fishermen gatheron the shorelinein Ohrid.

The catch of Lake Ohrid trout is threatened by overfishing and thedegradation of traditional spawning habitats.


into the lake through rainfall and runoff. Thesepollutants add to the pollution coming fromsewerage. Once the sewage collection andtreatment system in Pogradec is completed,sewerage may no longer be the largestcontributor of phosphorus to Lake Ohrid;runoff from the watershed may be.

Agriculture is a major contributor ofphosphorus, pesticides and sediments to bothLake Ohrid and Lake Prespa. Its impacts couldbe reduced by implementing “bestmanagement practices” on the farms in thewatershed in both Albania and Macedonia.These practices include actions for managingmanure and reducing soil erosion, especiallyaround streams. Better management practiceson pasturelands with high densities of livestockand irrigated croplands could be implementedto reduce the phosphorus coming from theseareas. Reduced pesticide use in orchards andirrigated fields would slow the inputs of theseharmful chemicals.

In developed areas, urban planning andzoning in critical areas of thecities and towns could helpselect appropriate locations forenvironmentally sound newdevelopments, and help reducethe pollution coming fromexisting communities. Newtourist establishments must fitinto these plans to protect theecological health of the lake.

Although theconcentrations of phosphorusmeasured by scientists in LakeOhrid still suggest anoligotrophic condition in thislake, the living organisms showa different story. A verydifferent make-up of plants

and animals has become established along theshoreline in developed areas, especially fromthe River Sateska to Radozda near Struga, inthe vicinity of Ohrid and near St. Naum inMacedonia, and near Tushemisht and Pogradecin Albania. The “bioindicator” species thatmake up this community are sending amessage that the unique biodiversity of the lake

OVERALL ASSESSMENT OF THESTATE OF THE LAKE OHRID ECOSYSTEM

When all the evidence scientists havegathered is combined, it provides a very clearpicture of a unique and fragile ecosystem thatis changing significantly and is at risk of seriousdecline. A key ecological characteristic of LakeOhrid throughout its history has been its clearwater. But in the last few decades, humanactivities in the watershed have changed thiscondition. They may have “aged” Lake Ohridmore in the past several decades than in theprevious thousands of years.

Although the shores of Lake Ohrid havebeen inhabited since prehistoric times, there hasbeen a dramatic increase in the humanpopulation in the basin in the last few decades.The beautiful vistas, temperate climate, and richcultural and natural heritage will continue toattract both residents and visitors to the basin.Therefore, a comprehensive management planthat accommodates this growth whileprotecting the environment is urgently needed,or the very qualities that attracted the people inthe first place will be lost.

Population growth and agricultural activities are changingLake Prespa and Lake Ohrid and compromising their health.

The condition of Lake Ohrid is intimatelytied to its watershed. Agricultural activities,forestry practices, mining, municipaldevelopment, and the tourism establishments,especially those along the shoreline, are allproducing pollutants that can make their way


may be permanently altered unless moreaggressive management actions are taken inthe future to reduce the amount of pollutionentering the lake.

The water quality of Lake Prespa has alsobeen affected by human activities. Althoughthis lake is naturally more nutrient-enrichedthan Lake Ohrid, agricultural activities andhuman wastes have greatly accelerated thiseutrophication. Irrigation may also becontributing to the lower water levels in thelake. Lake Prespa is choked with algae andaquatic plants and low oxygen levels occurevery summer. Because Lake Prespa drainsinto Lake Ohrid through the porousmountains between the lakes, a water qualityrestoration plan must address the pollutionproblems in the watersheds surrounding bothlakes.

The changes in the condition of LakeOhrid have appeared slowly because thevolume of water in the lake is so large.Likewise, improvements will also occurslowly, as new water flows into the lake. Ittakes about 70 years to replace all of the waterin Lake Ohrid. Therefore, aggressive actionto keep the lake in an oligotrophic conditionis the best management strategy.

In the 1980s, the construction of a sewagecollection system for the Macedonian townsalong Ohrid Bay dramatically reduced thelevels of harmful bacteria and viruses in thewater in this section of the lake. This was avery important and positive step for the healthof the people using the lake for drinking waterand recreation. Unfortunately, there are stillsections of the coast in both countries whereharmful bacteria from human waste poses asignificant risk to those who rely on LakeOhrid for drinking water or for recreationalactivities. The problem is most acute in theregion around Pogradec, Albania, but thesewerage system that has been designed forthe town should solve this problem. It willalso reduce the phosphorus loading to thelake.

The commercially important fish speciesin Lake Ohrid, especially Lake Ohrid trout,have been harvested at unsustainable levels inrecent years and the populations of trout arein immediate danger of collapse. Humanactivities along the shoreline also threaten thespawning and wintering grounds of both the

Ohrid trout and other fishes, including the bleakand the carp.

To preserve and restore the fishery, Albaniaand Macedonia must manage the fishpopulations jointly, with similar requirements inboth countries. A sustainable level of harvestfor each commercial species in the lake mustbe established, and vigorous enforcement mustfollow. Critical aquatic habitats, including thespawning habitats along the shoreline, must alsobe protected with strict regulations. Withoutimmediate action, the livelihood of thefishermen on both sides of the lake maydisappear.

There is cause for optimism. The LakeOhrid Conservation Project has brought localauthorities from both countries together inpositive ways and both individuals and groupson both sides of the lake are increasingly awareof their role in the ecosystem. The newtransboundary communication has served bothcountries well during the ethnic and politicaltensions in the border regions during the pastyear few years. In the future, a legal basis forthe Lake Ohrid Conservation Project in the lawsof both Macedonia and Albania could furtherstrengthen the program and move it into thenext phase.

Lake Ohrid and Lake Prespa are your lakes.What you do matters. The lakes need yourstewardship. Get involved. The Green Centersin Pogradec, Ohrid, and Struga are there to helpyou. They can connect you with organizationsactively working to restore the watershed andprotect the lakes. By working together, we canall help ensure healthy lakes for ourselves andfor future generations.

The Green Center on the waterfront in Ohrid. Green Centershave also been established in Struga and Pogradec.


You can help too!

• Buy and use low phosphate laundry detergents.

• Keep livestock out of streams and rivers.

• Plant grass, shrubs or trees along eroded stream banks.

• Wash your car away from the lake and other waterways.

• Work with local officials to manage the fishery harvest sustainably.

• Put all your trash in the solid waste bins in your town or community.

• Protect stream and lakeside vegetation – to prevent erosion and provide wildlife habitat.

• Never pour hazardous materials or oil down your sink or toilet or on the ground.

• Minimize your use of chemical fertilizers and avoid use of pesticides and herbicides altogether.

• Get involved! Learn about our lakes and support local efforts to protect them.

For further information, contact:

In Macedonia:Mr. Dejan Panovski, DirectorProject Implementation Unit of the Lake

Ohrid Conservation ProjectP.O. Box 286000, OhridRepublic of MacedoniaPhone: +389 46 263 743

In Albania:Mr. Arian Merolli, DirectorProject Implementation Unit of the Lake

Ohrid Conservation ProjectLaboratori i Monitorimit te Liqenit te OhritPogradecRepublic of AlbaniaPhone: +355 832 2237

A State of the Environment Report - LakeNet - World … of Env. Report Mar03.pdfThe common problems...

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