| Abstract: | The horizontal distribution of epi- and metalimnic zooplankton species in the northern region of the Bothnian Sea was studied in July and August 1975. The distribution was determined by vertical sampling with plankton nets at randomly selected stations in two areas (4 and 8 km2). Most species were clearly nonrandomly distributed in these two sampling areas. Horizontal patchiness within areas of a few km2 could be shown by grouping closely adjacent stations according to similarity or difference in average values. At the individual stations, there were only a few cases where any marked deviations from randomness were found. The age distributions of copepods differed in different parts of the areas. This is thought to be an important factor for the creation of patchiness. |
