Food and growth of arctic char, Salvelinus alpinus (L.), in the Cumberland Sound area of Baffin Island

Abstract

Arcticchar, Sahelinusalpinus (L.), captured during the summer, 1972, in Cumberland Sound, Baffin Island, fed mainly on planktonic amphipods (Pavathenii~fo libellula, Pseudalibr-otirs glacialis), copepods (Calarius hyperboreits), and fish (Boreogadus suida, Myoxocephakus sp.), but failed to utilize coelenterates, planktonic gastropods, and epi-and infauna. The considerable variation in the species composition of the diet of char of different lengths was due primarily to size selection. The average length of all individuals in stomach contents and of representatives of most food species increased with the length of fish. The minimum and maximum length of frequently ingested organisms increased four and 90 times, respectively, as char increased from 4 to 85 cm. Char less than 10 cm in length captured in rivers tributary to the Sound fed mainly on larval Chiroiiomidae (Eickieffeviella bavaria) during the summer, whereas those longer than 10 cm fed predominantly on other char. During the winter the stomachs of the smaller individuals were always empty while the diet of the large char was restricted to other fish. Most species available to the char were consumed in proportion to their relative abundance in the rivers. The dry weight of stomach contents, when expressed on a unit weight basis, decreased with the wet weight of char in both fresh and saIt water. Thus, fish 10 g in weight contained approximately 1.5 times more food in their stomachs than those weighing 1000 g. The stomach contents of char captured in salt water weighed approximately I1 times more than those of char of comparable size captured simultaneously in fresh water. The fish fed at random intervals during the day and ceased feeding at night. Arctic char, at all sampling areas, had reached a length of approximately 9.6 crn after four years. Upon migrating to salt water, their growth rate increased sharply with the result that after eight years they were 26.5 cm in length, reflecting food availability. The growth rate gradually decreased in fish older than nine years so that 20 year olds were approximately 70.0 cm in length.

Marine feeding patterns of anadromous brook trout (Salvelinus fontinalis) inhabiting an estuarine river fjord

“…Amphipods in addition to sand lance were also the dominant prey items in trout sampled between late August and early October in the Matamek River estuary (Whoriskey et al 1981). These observations were also consistent with earlier studies involving the anadromous form of brown trout (Salmo trutta) and Arctic char (Salvelinus alpinus) (Moore and Moore 1974;Pemberton 1976;Knutsen et al 2001). Other than a few occurrences of sticklebacks and sand lance in the spring and fall, fish were infrequently encountered in stomachs of first-year migrants captured in the SMB.…”

Food resource partitioning between stream-dwelling Arctic charr Salvelinus alpinus (L.), Atlantic salmon Salmo salar L. and alpine bullhead Cottus poecilopus Heckel, 1836: an example of water column segregation

“…The present study exemplifies how the differences in the use of surface prey (terrestrial prey and emerged aquatic insects) among sympatric species can constitute an important adaptive feature to reduce interspecific competition in riverine fish communities during the summer. Thus, our findings suggest that Studies describing the trophic ecology of Arctic charr in running waters are scarce (but see Moore & Moore, 1974;Stenzel, 1987;Sinnatamby et al, 2012;Sánchez-Hernández et al, 2016). Moore & Moore (1974) observed that small Arctic charr (\100 mm) fed mostly on Chironomidae larvae.…”

“…Thus, our findings suggest that Studies describing the trophic ecology of Arctic charr in running waters are scarce (but see Moore & Moore, 1974;Stenzel, 1987;Sinnatamby et al, 2012;Sánchez-Hernández et al, 2016). Moore & Moore (1974) observed that small Arctic charr (\100 mm) fed mostly on Chironomidae larvae. Likewise, Stenzel (1987) found that the diet of juvenile Arctic charr is mainly composed of chironomids and other dipteran larvae.…”

“…There are numerous reports on trophic aspects of lacustrine Arctic charr populations (e.g. Langeland et al, 1991;Cavalli et al, 1998;Eloranta et al, 2015), but we know little about their feeding in running waters, although the few available studies suggest that the diet of riverine Arctic charr mainly is composed of Chironomidae larvae (Moore & Moore, 1974;Stenzel, 1987;Sinnatamby et al, 2012). Laboratory studies show that Arctic charr can feed in the water column, even though they may take a substantial proportion of their food from the bottom (Jørgensen & Jobling, 1990;Brännäs & Alanärä, 1992).…”

Schooling behaviour of arctic cod, Boreogadus saida, in relation to drifting pack ice

“…Its distribution is circumpolar at high northern latitudes and in the limited diversity of the arctic marine food web, this fish represents the major link between the secondary producers (zooplankton) and the top carnivores (marine mammals and seabirds) (Andriashev 1964, Bradstreet', Hobson & Welch 1992b, Mansfield et al 1975, Moore & Moore 1974, Sergeant 1973. The diet of arctic cod consists mainly of copepods and amphipods (Bradstreet et al 1986).…”