15th
 anniversary
 of WNP

WIGRY NATIONAL PARK

Special issue

of "WIGRY"
quarterly
magazine


Webdesign: 
KAJA
 
2004

Maciej Kamiński

Waters

Unique aquatic ecosystems single out the Wigry National Park both in the country and in the world. Lake Wigry and 40 smaller lakes, the Czarna Hancza River, other small rivers and streams, and also water and swamp habitats are a place of occurrence of plant assemblages and animal communities, both rich in species, and the most characteristic landscape features of the Park. Within the Park, there are nearly all kinds of aquatic lowland ecosystems of varied fertility, thermal and oxygen conditions, and concentration of humus compounds.

 Since the moment of its establishment, the conservation of resources and of all the natural richness of lakes and rivers has been the Park’s goal. The tasks in the Park include, among others, the keeping of water conditions, protection of waters against pollution, preservation of diversity of animal and plant species occurring in the Park, preservation of their assemblages and communities and their habitats, and also restitution of aquatic species of organisms which became extinct as a result of man’s activities.

On the other hand, the national park also protects, in areas under strict protection, the course of spontaneous natural processes. Eight water reservoirs of total area of 255.45 hectares have been covered by strict protection which ensures maximum restrictions on direct human pressure. They are an oasis for species avoiding man’s closeness and an unusually valuable object for scientific studies.

The biggest threat to the quality of the Park’s waters is their nutrient-enrichment (eutrophication). Over decades Lake Wigry has been heavily polluted by sewage discharged into the Czarna Hancza from Suwalki. Thanks to thorough modernization of the Suwalki sewage treatment plant in the years 1993–1995, the efficiency of removing nitrogen and phosphorus from sewage has greatly increased. At present, the lake is in the state of relative balance between the inflow of biogenous substances, their use within the tank and carrying them outside the lake – without a further, distinctive increase in its nutrient-enrichment.

Wigry – the biggest, the deepest and the most attractive lake of the Wigry National Park. Phot. M. Kamiński

Since the establishment of the national park, also other sources of water pollution have gradually been eliminated. Activities undertaken by the WNP and local governments included, among others, a construction of a sewage treatment plant in the village of Bryzgiel (1996) and installation of domestic sewage treatment plants at buildings belonging to the Park. The construction of washing facilities and toilets at the Jastrzeby camp-site and on the beach in Krzywe favoured the reduction in water pollution.

The protection of water quality in the Park has been achieved not only through reduction in sewage inflow, but also through limiting the effects of nutrient-enrichment. Since taking over the fish farming in Wigry (in 1992), the Park has actively been shaping composition and number of fish species through fish stocking and selective fish catches.

The main trends of ichthyofauna protection in the Park consist in:

• keeping the occurrence of numerous population of Coregonidae family – the European whitefish and the powan, whose range in Poland is shrinking because of eutrophication;

• increase in the number of big predatory fish, particularly the pike. In protection practice a method of biomanipulation was applied, which consist in reducing the number of smaller fish which feed mostly on tiny, suspended in water plankton animals, in this, crustaceans filtering water. This can be done through changes in the number of predatory fish. Plankton crustaceans, if there are a lot of them, are able to reduce significantly the number of small algae, which are filtered from water by them and eaten. Therefore, although not directly, a high number of pikes and other big predatory fish can contribute to the increase in clarity of water and, for example, improvement in living conditions for submersed plants;

• restitution of species which lived in the past and became extinct for different reasons or are rare: the lake trout, the European catfish and the brown trout. There are also attempts to restitute the native species of crayfish;

• selective fish catches, aiming at reduction in the number of fish from the carp family and the oldest European whitefish feeding on plankton.

The regulations concerning angling and water tourism are subordinated to the aims of protection of the Park’s waters.

Suchar Zachodni - one of the polyhumic reservoirs. Phot. M.Kamiński

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