Annual Report For The Year 1949 : And Short Papers

In the Director's Report for the year 1948 a general survey was given of the work program of the Institute and during last year the research has continued on the whole along the same lines. This Report confines itself therefore to an account of the progress made during the year 1949 within the limits of the program set up.

Chironomids and Other Bottom Animals of the Oligotrophic Lakes in South Sweden : A Contribution to the Knowledge of the Bottomfaunistical Characteristics of the Swedish Oligotrophic Lakes

Problems. Methods. Material. There are more than 85000 lakes in Sweden, the majority of which belong to the oligotrophic type sensu Naumann, and which present an inexhaustible field for investigation. In view of the varied and complicated nature of the problems and the young age of limnological science it is natural that the knowledge of these lakes in spite of the efforts of many investigators should still be fragmentary. This holds good also of the bottom fauna which in many respects is so important. When, in 1941—1942, I was working on a quantitative material of bottom animals from oligotrophic lakes in Jämtland, North Sweden, this lack of data was strongly felt. There was no solid holding-ground for a comparison with other lakes in Sweden, and many factors indicated that the production of the bottom animals in oligotrophic lakes in Sweden was considerably underestimated, probably because of the methods not being quite satisfactory. Particularly conflicting results had been reached by previous investigators as regards the influence of the humic standard on the bottom fauna, which is a vital problem concerning the Swedish lakes. As regards the chironomids constituting, as is well known, the most important group among the bottom animals in the Swedish lakes, our almost complete lack of knowledge was most deeply felt. It was clear that a real understanding of the relationship between the different laketypes and the profundal fauna could only be obtained by determining the species represented by the chironomid larvae. The very fact that certain lakes in Jämtland that Naumann would undoubtedly have characterized as oligotrophic had a chironomid fauna, which according to the valid typology of the lakes based on the bottom faunistical conditions must be regarded as belonging to the mesotrophic type, was in itself an inducement enough for a closer study of chironomids and their dependence on environmental factors. Thus important problems were waiting for a solution. To contribute to this I started studies of the bottom fauna in 1942 with a particular regard to the chironomids in the Aneboda-Växjö district in the central part of the South-Swedish highland. These studies were concluded in the autumn of 1948

Annual Report For The Year 1948 : And Short Papers

The Institute of Fresh-Water Research, Drottningholm, (formerly: The Swedish State Institute of Fresh-Water Fishery Research) was founded in 1932. The Institute was directly under the Fishery Bureau of the Board of Agriculture with the chief of that Bureau as its director. On July 1st 1948, the Swedish Fishery Board was established, and the Institute’s formerdirector — fil. dr. Gunnar Alm — consequently appointed to the administration of freshwater fisheries within the Board. The Institute now represents fresh-water fishery research within the Board under the supervision of its own director. During the past years the results of the research have been published as reports appearing at various intervals. A list of all the reports published hitherto is found on the cover of this booklet. Considering the vast amount of research being carried on at present at similar institutes in other countries, it should, however, be of interest to publish an Annual Report, a survey of the year’s work at our Institute and short reports from the staff. More comprehensive work will, however, even in the future appear as separate papers.