Respiration rates of various geographical strains of Crassostrea gigas were compared to assess the respiratory expenditure as a physiological indicator of catabolism (cost of maintenance). Parental oysters, sampled in France (Marennes-Oléron), Japan (Hiroshima), Taiwan (Tunkang) and Spain (Cadix), were differentiated by both their geographic origin and by mitochondrial DNA markers, allowing the distinction between the two cIosely related taxa Crassostrea gigas and Crassostrea angulata. After reproduction of these parental oysters, respiration rates of spat of each strain, reared under common controlled conditions, were individually estimated at 20 oC by using a volumetric microrespirometer. Our results demonstrated that physiological variability existed among the Crassostrea gigas strains and is likely to be related to physiological differences between geographical regions and/or genetic adaptations. The French strain showed the highest rates (0.71 IlL•h-I), while the Japanese, Taiwanese and the hybrid between Spanish and French strains consumed less, 0.53, 0.43 and 0.40 IlL•h-l, respectively. Our results confirmed the discrepancies previously suggested between Crassostrea gigas and Crassostrea angulata. Comprehensive physiological assessments should be carried out over a wide temperature range to confirm our results and to further evaluate growth potential. Appropriate decision making based on these studies will help future shellfish management in shellfish rearing areas such as the overstocked Marennes-Oléron Bay.

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The species composition and biomass of material collected in the summers 1981 and 1983 from 69 stations in the Hornsund fiord were analysed. 48 macroalgal taxa were found: 13 green algae, 18 brown algae and 17 red algae. 19 of these taxa were not reported from the nearby Isfjorden. The overall biomass for the littoral zone varied from 0 to 216gnT2 formalin d.w., although in J of samples the biomass was between 20 and 80 gm_z. The dominant species were Fucus distichus, Acrosiphonia duriusada and Pilayella littoralis. Using cluster analysis, an attempt was made to delimit regions with a characteristic species composition. The results obtained, however, do not permit this in the littoral zone of the Hornsund fiord.

Latata, A. 1990: Photosynthesis and respiration of some marine benthic algae from Spitsbergen. Polar Research 8, 303-307. Light-photosynthesis curves for 9 species of benthic algac from the Hornsund fiord were detcrmined. As a result of adaptation to the conditions in the Arctic, benthic algae from Spitsbergen have a low rcquirement of light. Saturation and compensation points are low and within a range typical for shadow-tolcrant plants.The values for gas cxchangc rates indicate that Arctic algac have lower Photosynthetic capacity than temperatc spccics.

The phytobenthos of the Hornsund fiord, SW Spitsbergen IRENEUSZ FLORCZYK AND ADAM LATALA Horczyk, I. & Latala, A. 1989: The phytobenthos of the Hornsund fiord, SW Spitsbergen. Polar Research 7, 29-41. The species composition and biomass of material collected in the summers 1981 and 1983 from 69 stations in the Hornsund fiord were analysed. 48 macroalgal taxa were found: 13 green algae, 18 brown algae and 17 red algae. 19 of these taxa were not reported from the nearby Isfjorden. The overall biomass for the littoral zone varied from 0 to 216g1n-~ formalin d.w., although in f of samples the biomass was between 20 and 80 gm-'. The dominant species were Fucus distichw, Acrosiphorzia duriuscula and Pilayella littoralis.Using cluster analysis, an attempt was made to delimit regions with a characteristic species composition.The results obtained, however, do not permit this in the littoral zone of the Hornsund fiord.lreneusr Florczyk and Adam Lataia,