This paper describes the macroflora and macrofauna associated with two bull kelp species, Laminaria hyperborea and L. digitata, at the island of Helgoland, North Sea. During a study period of seven months (March-September 1987), 29 macroflora species and 125 macrofauna species were found. The dominant taxonomic groups were Polychaeta (25 species), Bryozoa (17), Amphipoda (14), Hydrozoa (10) and Ascidiae (8). The species maximum was in July. In general, L.hyperborea was preferred as a substrate for settlement to L. digitata. Compositio n of the communities associated with kelp changed.during the season accordim:j to exposure to wave action, and according to location on the kelp thallus. The rhizoid community of both kelps bore more species at exposed locations. Wave-exposed L. digitata lacked obvious faunal settlement on both phylloid and cauloid. Phylloid and cauloid of L. hyperborea were chosen as an attractive substrate at both sheltered and wave-exposed locations, showing an association of encrusting bryozoan and hydrozoan colonies.

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Larvae of the Aesop shrimp Pandalus montagui Leach (Decapoda: Caridea: Pandalidae), were reared in the laboratory at 5 different temperatures (6, 9, 12, 15, and 18°C), and their growth patterns were analyzed in terms of molting frequency, size increments (total length, TL, carapace length, CL), and increase in larval dry weight (W). Pandalus montagui passed through 6 zoeal and 2-5 decapodid stages. While 2 of the latter occurred consistently (obligatory stages), up to 3 additional (facultative) decapodid stages were passed before metamorphosis to the first juvenile. Molting occurred at regular intervals, with little interstage variation, so that the instar number could be described as a linear function of the time of development, with an increasing molting frequency at increasing temperatures. A nonlinear relationship (power function) was found between average intermolt duration and temperature; this regression was linked with data for water temperatures measured during the spring near Helgoland (southern North Sea), in order to predict the approximate duration of larval development and peak settlement in the field. From instar I-VIII, larval size increased as a linear function of the number of molting cycles, but no significant growth and no further morphological changes were observed in later (facultative) larval stages. The morphometric relationship between TL and CL remained linear throughout larval development, with an increasing trend in the TL:CL quotient. W increased exponentially with the number of instars, and as a power function of larval size. The overall patterns of larval development and growth in P. montagui are compared with those known from other pandalid species and in other caridean shrimps.