Three-spined stickleback fry (mean length 20 mm, mean weight 14 mg) were reared for 14 days alone and in groups of six in a constant per cajJita water volume. The fish originated from two habitats (rock-pools, sea) of different predation pressure. The fry were fed naupljj of Arremio and commercial aquarium fish food cid lihifurn. Specific growth rates of solitary and schooling fry differed and were also affected by their origin. The specific growth rates of solitary fry from the sea averaged 1 -O'%I day ~ ' (length) and 6.0% day ~ ' (weight) and those of solitary rock-pool fry 1.1 and 6.7'%,, respectively. For group-reared fish the corresponding values were 1.2% (length) and 6.6' Yo (weight), and 1.3% (length) and 7.6% (weight). The finding that schooling sticklebacks grow faster than solitary ones implies that grouping enhances fitness in stickleback fry under the conditions of our experiments.

Using brook (Culaea inconstans) and 10-spined (Pungiiius pungitius) sticklebacks we examined body-size related schooling behaviour. Small and large sticklebacks were allowed to choose between two test schools, of small and of large individuals, with and without a piscivorous fish (Oncorhynchus mykiss) visible. Sticklebacks of both species preferred the company of fish of matching body size: small fish associating with a school of small fish, large fish with a school of large fish. While no interspecific differences were found in responses to school selection, body size and predator presence did affect selection of school-type. In both species, small fish tended to show a stronger preference for matching schools. The preference was enhanced in small fish with presence of a predator, but not in large fish. These observations are further evidence for assortative schooling in sticklebacks.

Nach drei verschiedenen offizinellen Verfahren wurden die aromatischen Wiisser Aqua Floris Aurantii, Aqua Menthae piperitae, Aqua Foeniculi, Aqua Aniisi und Aqua Rosae hergestellt. Die Verteilung des Oles zwischen Wasser und Rezeptur-Hilfsmitteln, wie Filter und Talk, konnte gravimetrisch fiir die gesamten ole und gaschromatographisch fiir die einzelnen Substanzen der ole quantitativ ermittelt werden. Die Veranderungen in der Zusammensetzung des Oles im aromatischen Wasser wurden wiihrend einjtihriger Lagerungszeit verfolgt.

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