Feeding by the chaetognath, Sagitta elegans, at low temperatures in Vineyard Sound, Massachusetts1

Abstract

Feeding rates were determined for S. elegans feeding in Vineyard Sound, Massachusetts, at a temperature of 0°C by applying a digestion time (10.2 h), obtained from laboratory observations, to an analysis of gut contents. The specific daily ration of large individuals was about l-2% of body dry wt*d-', that of small chaetognaths (3.5 mm) was about 46%. Feeding rates for all but the smallest animals are similar to those predicted from respiration data; the small& individuals consumed more than their estimated no-growth requirements.

Feeding of the chaetognaths Sagitta elegans and S. setosa at different seasons in Gullmarsfjorden, Sweden

“…Decreased feeding activity during the day in Sagitta elegans has been reported by Wimpenny (1937Wimpenny ( , 1938, Rakusa-Suszczewski (1969), Pearre (1973), Sullivan (1980), Feigenbaum (1982 and Ohman (1986). In this study, the die1 feeding behaviour of S. elegans varied with season, showing a significant decline in feeding during the day in July, but not in December.…”

“…of 10 S. elegans eating Calanus at 6OC). Pearre (1973) and Feigenbaum (1982) (after omitting prey in the forward part of the gut) also neglected cod-end feeding in S. elegans. Voiding and defaecation of gut content may perhaps occur but information concerning this is scarce.…”

“…The difference in cannibalism is notable, and it does not support the hypothesis proposed by Stone (1965) (statistical support for this was provided by Pearre 1982) that cannibalism increases with species size (see also Feigenbaum & Mans 1984). Feigenbaum (1982) found little cannibalism in S. elegans in early spring in Vineyard Sound, while Pearre (1981) found that cannibalism played an important part in the energy intake of the larger stages in December in Bedford Basin.…”

“…needs many trials to catch a prey, searching for local concentrations of prey might b e favourable. Feigenbaum (1982) gave a DT of 10.2 h (mean of 17 measurements, range of 4.6 to 16.7 h) at O°C, based on copepods of different sizes a n d numbers and Sagitta elegans starved for 2 to 4 d before the experiments started. Kuhlmann (1977) reported a DT of 2.5 h at 15°C for S. elegans eating copepods (based on 12 measurements according to Kuhlmann 1976).…”

Relationship between spatial distribution of chaetognaths and hydrographic conditions around seamounts and islands of the tropical southwestern Atlantic

“…warm water, cold water, mixed water). The oceanographic features of the waters can also influence aspects of chaetognath ecology, such as growth, sexual development and feeding rate (McLaren 1963, Feigenbaum 1982.…”