CONTENTS &
ABSTRACTS
In
English. Summaries in Estonian
Proceedings of the Estonian Academy of Sciences.
Biology. Ecology
Volume 50 No. 3
September 2001
International marine
scientific activities in the Baltic Sea with special reference to Estonian
participation; 139–157
Bernt I. DYBERN and Stig FONSELIUS
Abstract. The
development of international marine research in the Baltic Sea during the 20th
century and Estonian participation are described. The organization of the
International Council for Exploration of the Sea and its different working
groups connected to the research in the Baltic Sea is explained. The founding
and activities of the Conference of Baltic Oceanographers and the Baltic Marine
Biologists are described. The international synoptic investigations of the
Baltic and especially the “Cooperative Synoptic Investigation of the Baltic”,
“The International Baltic Year”, “Baltic Open
Sea Experiment”, “Patchiness Experiment”, and “The Skagerrak Experiment” and
their results are briefly discussed. Some other recent international
cooperation is also touched upon. Estonian participation in these activities is
explained.
Key words: Baltic Sea, investigations, international
organizations, Estonian participation, history.
Investigations on the Baltic
Sea conducted by the Department of Marine Biology, Institute of Zoology and
Botany (Tartu, Estonia), 1975–90; 158–168
Kai PIIRSOO, Arvi JÄRVEKÜLG, Valli PORGASAAR,
Tiiu TREI, Malle VIIK, and Sirje VILBASTE
Abstract. A brief review is given of the investigations conducted by the former Department of Marine Biology of the Institute of Zoology and Botany of the Academy of Sciences of the Estonian SSR, Tartu, Estonia. Major research projects and their results are presented, and the papers published on the materials collected in 1975–90 are listed.
Key words: Baltic Sea, Estonian coastal waters, hydrobiological investigations.
History of investigations on
the ecosystem of Lake Peipsi; 169–179
Külli KANGUR, Juta
HABERMAN, Andu KANGUR, Peeter KANGUR, Anu MILIUS, Helle MÄEMETS, Reet LAUGASTE,
and Ervin PIHU
Abstract. The investigations of the biota in L. Peipsi, one of the largest lakes of Europe, started already one and a half centuries ago, complex studies were initiated in the 1930s. The paper gives a brief survey of research into the hydrochemistry, macrophytes, bacterio-, phyto- and zooplankton, zoobenthos, fishes, and fisheries management of the lake. Special attention is paid to the main findings. Intensive anthropogenic eutrophication of L. Peipsi started in the 1970s. The nutrient content reached its maximum in the 1980s and decreased thereafter. An expansion of reeds, increase in the similarity between different lake parts, and decline of rare macrophyte species have occurred. Regarding phytoplankton, L. Pihkva has become strongly eutrophic, whereas L. Peipsi s.s. has eutrophied to a smaller extent, its northern part has maintained a mesotrophic appearance. In 1965–99, the number but not the biomass of zooplankton increased. The number of small-sized zooplankters (especially rotifers) increased. No essential changes in the composition and distribution of macrozoobenthos in connection with eutrophication of the lake were observed. Dreissena polymorpha, introduced accidentally in the lake in the 1930s, has become the most significant animal population in L. Peipsi. Considering annual fish catches L. Peipsi surpasses all large lakes in North Europe. The main commercial fishes are smelt, perch, pikeperch, roach, bream, pike, and until the 1990s also vendace. At present it is changing into a smelt–bream–pikeperch lake.
Key words: hydrochemistry, macrophytes, bacterioplankton, algae, zooplankton, zoobenthos, fisheries management.
History
of hydrological and biological investigations of Lake Võrtsjärv; 180–193
Peeter NÕGES, Andu KANGUR, Ain JÄRVALT, and
Tiina NÕGES
Abstract. In the18th and 19th centuries the first data on fisheries, hydrology, and aquatic vegetation in Lake Võrtsjärv were published by Baltic German naturalists. The comprehensive investigation by the Lake Commission of the Estonian Naturalists’ Society in 1911–13 led by M. von zur Mühlen is a milestone in the scientific level. During more than 30 years after the publication of a profound monograph in 1920 by M. von zur Mühlen and G. Schneider only a few investigations were carried out on L. Võrtsjärv. The bulk of the present long-term data set on L. Võrtsjärv has been collected during the existence of the Limnological Station since the 1960s.
Key words: Lake Võrtsjärv, history of investigations, hydrology, water chemistry, hydrobiology.
Littoral zone research in
the Neva estuary (eastern Gulf of Finland): History and perspectives; 194–199
Vadim E. PANOV, Sergey
M. GOLUBKOV, and Marina I. ORLOVA
Abstract. The history of littoral zone research in the Neva estuary, the largest estuary in the Baltic Sea, is described. Environmental problems, including effects of eutrophication and introductions of alien species, are discussed. A brief outline of future research is provided.
Key words: Gulf of Finland, Neva estuary, littoral zone, eutrophication, alien species, history of research.
Zooplankton studies in the
Neva estuary (Baltic Sea): A brief excursion into history; 200–210
Irina V. TELESH
Abstract. Zooplankton studies in the Neva estuary started in the early 20th century. During those pioneer investigations and in the following several decades mostly qualitative data were collected. Until the end of the 1970s, plankton research in the area was irregular and numerical data were scarce. In the 1980s zooplankton studies became an important part of comprehensive hydrobiological investigations aimed at evaluation of the functioning of the estuarine ecosystem. Recent studies have demonstrated the necessity to pay more attention to the problem of biological invasions of aquatic alien species to and from the ecosystem of the Neva estuary. At present this problem, together with the assessment of the response of zooplankton communities to anthropogenic stress, is among the major items of zooplankton research in the Neva estuary.
Key words: zooplankton, Neva estuary, history of research.
History of aquaculture
research in Estonia; 211–221
Tiit PAAVER, Tiiu TOHVERT, and Mart KANGUR
Abstract. Fish farming was initiated in Estonia in the 1890s by German landowners, who reared brown trout and common carp in ponds. Development towards intensive fish farming began in the 1960s. The Department of Fish Farming of the Estonian Institute of Animal Breeding and Veterinary Science carried out applied research on problems related to freshwater pond farming. The main topics of the research included technology of carp culture under the climatic conditions of Estonia, improvement of the performance of carp strains by selective breeding, measures of treatment of fish against parasitary diseases, and problems of rainbow trout farming in fresh water. The Laboratory of Marine Fish Rearing of the Tallinn Department of the Baltic Fishery Research Institute dealt with a broad range of topics of fish farming in sea water, feed composition and quality, fish physiology and diseases, construction of recirculation systems, etc. in the 1970s–80s. The Department of Hydrobiology of the Institute of Zoology and Botany of the Estonian Academy of Sciences carried out studies on the genetics, physiology, morphology, and parasitology of carp and rainbow trout.
Key words: aquaculture, research history, common carp, rainbow trout.