Nototheniid and myctophid Wsh are primary prey for marine piscivores, yet little is known about their nutritional value. In this study, we characterized the proximate composition [PC: water, fat (neutral lipids), crude protein (CP) and ash] and energy density (ED; kJ g ¡1 ) of Wfteen Wsh species from McMurdo Sound and the Ross Sea, Antarctica. We assayed the entire Wsh for all species except for the large Antarctic toothWsh, Dissostichus mawsoni (muscle tissue only). On a wet mass basis (WM), Wsh were variable in composition: moisture content ranged from 64.9 to 87.3% WM, fat from 0.5 to 17.4% WM, CP from 7.7 to 16.7% WM, ash from 11.2 to 21.0% FFDM (fat-free dry mass), and ED from 2.9 to 10.3 kJ g ¡1 . Myctophids and pelagic nototheniids such as Pleuragramma antarcticum and D. mawsoni were high in fat content (7-17% WM), while a bathylagid and benthic nototheniids including most Trematomus spp. and Lepidonotothen squamifrons were low in fat (0.5-4% WM). The epibenthic Trematomus species (T. eulepidotus and T. lepidorhinus) were intermediate. Energy density tracked fat content, with highest values in myctophids and pelagic nototheniids. The variation in nutrient and energy density conWrms that prey composition must be taken into account when modelling energy and nutrient Xuxes within the Antarctic ecosystem. Further analyses of prey collected over a number of diVerent locations and seasons are needed in order to determine how the nutritional value of certain species might aVect annual or decadal variation in reproductive success or population size of top predators.

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Abstract:The reasons for the decline in some Atlantic salmon (Salmo salar) stocks in Newfoundland and southern Labrador are not fully understood, but many resource users consider predation by seals in rivers and nearshore waters to be a contributing factor. To address these concerns, local ecological knowledge (LEK) interviews with resource users (n = 57) were conducted at 29 rivers throughout the Province to evaluate the potential for seal predation over a 25-year period when major changes were occurring in the structure of the Northwest Atlantic ecosystem. Based on LEK, eight rivers frequented by harp seals (Pagophilus groenlandicus), nine by harbor seals (Phoca vitulina) and three by gray seals (Halichoerus grypus) were evaluated as having a high potential for predation. According to respondents, the relative abundance of seals at these rivers started increasing in the mid 1990s or 2000, depending on the seal species involved. Variation in potential predation from river to river was attributed to a number of factors including the distribution of forage fish, variability in local ice conditions, the geography of the river and ecology of seal species frequenting the area. Resource users provided a useful and, in many cases, new perspective on the spatial and temporal overlap of seals, particularly harp seals, capelin (Mallotus villosus) and salmon in some areas. However, quantitative seal diet information and knowledge of seal-salmon relative abundances are required to assess the biological significance of these results from a salmon conservation perspective.

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