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Juvenile lake trout, Salvelinus namaycush, of similar size were fed one of three isocaloric diets, each differing in protein and lipid content. Oxygen consumption and swimming performance were measured in a recirculating water flume at intervals throughout the 70-d feeding trials (10 °C). Swimming speed was increased by stepwise velocity increments (5 cm∙s−1) and oxygen consumption was measured at each velocity between 20 and 45 cm∙s−1. Oxygen consumption for a given speed did not differ significantly throughout the feeding trial nor among the diets implying a similarity in the quality and quantity of substrate catabolized for energy. Basal metabolism (0 cm∙s−1) was also independent of diet and feeding interval. Critical swimming speed increased with dietary and carcass protein content to suggest a direct association with muscle mass and number of myofilaments.

and F. &a/. H. Beamish. 1987. Age validation for the mountain brook lamprey, Ichthysmyzon greeleyi. Can. j. Fish. Aquae. Sci. 44: 901-904.Larval mountain brook lamprey, Ichthysmymon greeleyi, were collected from Bent Creek in western North Carolina to provide information on the age structure of the population and to validate statslith banding patterns as an aging technique. Larvae were injected with oxytetraeycline in winter and held in the laboratory at seasonally adjusted temperatures for 1 yr. Seatoliths from these larvae were examined over the course sf the study for the presence and persistence of oxytetracycline, and banding patterns which appeared after marking. Oxytetracycline persisted in all statoliths over the course of the study, and one complete annulus was formed ow each statoiith during the winter period when growth was slow. The larval period of I. greeleyi commences after hatching in late June and persists for 4.2-5.2 yr, with the oldest individuals being predominantly female.Les auteurs ont recueilli des larves de Jarnproie de rnontagnes (Ichtysmyzon greejeyi) dans le ruisseau Bent dans l'ouest de la Caroline du Nord afin de fournir des donnkes sur la structure demcsgraphique des Ages et de valider Bes anneaux dkposes dans les statolites comrne methsde de determination de \'Age. Bls ont inject6 aux larves de I'oxytetracycline en hiver et les ont gardees en labsratoire pendant 1 an 21 des temperatures ajustees selon la saissn. Pout au csurs de I'etude, ils ont examine les statolites afin de determiner la presence et la persistance de I'oxyt6tracyeline et des anneaux apparus apks B'injectisn. L'oxytetracycline est restee dans tous les statolites pendant i'ktude et ken anneau complet a et6 forme sur ckaacun d'eux pendant I'hiver quand la croissance etait lente. Chez I. greeleyi, la periode larvaire commence aprPs I'eclosion A la fin juin et dure de 4,2 5,2 a; les plus vieux individus ssnt surtout des fernelles.