Oxygen consumption, CO2 excretion, and nitrogenous waste excretion (75% ammonia-N and 25% urea-N) were measured daily in 4-g rainbow trout over a 15-day starvation period. Oxygen consumption and CO2 excretion declined while N excretion increased transiently in the mid-part of the starvation period but was unchanged from control levels at the end. Component losses (as percentage of total fuel used) of protein, lipid, and carbohydrate were 66.5, 31.1, and 2.4% respectively, as measured from changes in body weight and body composition, the latter relative to a control group at day 0. Instantaneous fuel use, as calculated from the respiratory quotients and nitrogen quotients, indicated that relative protein use rose during starvation, but contributed at most 24% of the aerobic fuel (as carbon). Lipid metabolism fell from about 68 to 37%, and was largely replaced by carbohydrate metabolism which rose from 20 to 37%. We conclude that the two approaches measure different processes, and that the instantaneous method is preferred for physiological studies. The compositional method is influenced by greater error, and measures the fuels depleted, not necessarily burned, because of possible interconversion and excretion of fuels.

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The collagenous dermis of the white rhinoceros forms a thick, protective armour that is highly specialized in its structure and material properties compared with other mammalian skin. Rhinoceros skin is three times thicker than predicted allometrically, and it contains a dense and highly ordered three-dimensional array of relatively straight and highly crosslinked collagen fibres. The skin of the back and flanks exhibits a steep stress-strain curve with very little 'toe' region, a high elastic modulus (240 MPa), a high tensile strength (30 MPa), a low breaking strain (0.24) and high breaking energy (3 MJm-3) and work of fracture (78 kJm-2). By comparison, the belly skin is somewhat less stiff, weaker, and more extensible. In compression, rhinoceros skin withstands average stresses and strains of 170 MPa and 0.7, respectively, before yielding. As a biological material, rhinoceros dorsolateral skin has properties that are intermediate between those of 'normal' mammalian skin and tendons. This study shows that the dermal armour of the rhinoceros is very well adapted to resist blows from the horns of conspecifics, as might occur during aggressive behaviour, due to specialized material properties as well as its great thickness.

Th e coastline inhabiting rove beetles (Coleoptera: Staphylinidae) of Atlantic Canada are surveyed. Th irty-three species have now been recorded in Atlantic Canada including 26 in New Brunswick, 15 in Newfoundland, 31 in Nova Scotia, and 13 on Prince Edward Island. Oligota parva Kraatz, Acrotona avia (Casey), Strigota ambigua (Erichson), and Myrmecopora vaga (LeConte) are all newly recorded in Canada, and Bledius mandibularis Erichson is newly recorded in Atlantic Canada. We retain A. avia as a species distinct from A. subpygmaea Bernhauer and designate a lectotype for A. avia. Ten new provincial records are reported, one from New Brunswick, six from Nova Scotia, and three from Prince Edward Island. Four functional groups, halobiont (obligate), halophile (facultative), haloxene (tolerant), and incidental coastal species, are distinguished and the fauna is examined from the perspective of the particular coastline habitats and microhabitats they have been found to inhabit.Fourteen of the 33 staphylinids are introduced, Palearctic species, and eight of these have been associated with historical dry ballast shipping to the region from Great Britain. A trophic analysis indicates that some species are phytophagous algae feeders, while others are either generalist predators, or predators specializing on particular taxonomic or functional groups of invertebrates. Finally, some attention is devoted to discussing the diminished areas of coastline environments such as coastal marshes, and the various kinds of environmental disturbances and degradations they have experienced. Th ese indicate the potential vulnerability of such coastal habitats and consequently of the communities of beetles that inhabit them.

The types of fuel burned by juvenile rainbow trout (17 g) during a 58-h period of aerobic sustained exercise were studied by respirometry. Attempts to measure fuel usage by depletion (the compositional approach) in these same fish were unsuccessful due to tack of detectable changes in proximate body composition. 02 consumption, CO2 excretion, and nitrogenous waste excretion (ammonia-N plus urea-N) were measured in individual fish swum continuously at 55% and 80% of maximum sustainable swimming speed and in non-swimming controls. 02 consumption and CO2 excretion increased with swimming speed, and decreased over time. Absolute rates of N excretion were independent of swimming speed and time. Instantaneous aerobic fuel use, as calculated from the respiratory quotients and nitrogen quotients, was approximately 47% lipid, 30% protein, and 23 % carbohydrate in non-swimmers at the start of the experiment. With increased swimming speed there was no change in absolute rates of protein oxidation, while lipid and carbohydrate oxidation both increased. Therefore, the relative protein contribution decreased with increasing speed but increased with swimming duration as the oxidation of other fuels declined over time. However, lipid oxidation predominated at all speeds and at all times. The relative contribution of carbohydrate increased with swimming speed and decreased over time. These results suggest that swimming becomes more efficient over time and help resolve uncertainties in the literature. We conclude that lipid is the main fuel of aerobic exercise, that protein catabolism is kept at minimum levels necessary for maintenance, and that