Summary
Observations of intermoult period, growth and maturation were made on krill which were transported from Antarctic waters and maintained in the laboratory in Australia over a three year period. The mean intermoult period (IP) for each of 10 specimens, with initial body lengths of 24.7=46.8 mm, kept at -0.5° C varied from 22.0 to 29.8 days (overall mean = 26.6 days). These measurements of IP are significantly longer than those obtained in some previous studies. Differences in experimental temperatures, light, body sizes and growth patterns of the specimens between studies are unlikely to be causes of these dissimilar results. The pattern of changes in body length (BL) varies from one individual to the next. The greatest increase in BL over a series of 4–5 moults ranged from 0.024 to 0.070 mm/day, which is equivalent to 0.0020 to 0.0086/day in body weight, assuming exponential growth. This maximum growth rate is about half the rate predicted from the growth scheme of Mauchline (1980) for wild krill. Comparison of growth data for other euphausiids suggests that Mauchline's scheme produces anomalous growth rate. The slower growth rate observed in the present study would extend the estimated life span of krill from 3–4 years, as calculated by Mauchline (1980), to 4–7 years. If krill undergo body shrinkage during the Antarctic winter the estimated life span might be even longer. Examination of the external sexual characters of moults showed both progression and regression of maturity stage in association with changes in BL.
Similar content being viewed by others
References
Bargmann HE (1945) The development and life history of adolescent and adult krill, Euphausia superba. Discovery Rep 23:103–176
Benayoun G, Fowler SW (1980) Long-term observations on the moulting frequency of the shrimp Lysmata seticaudata. Mar Biol 59:219–223
Clarke A (1976) Some observations on krill (Euphausia superba Dana) maintained alive in the laboratory. Br Antarct Surv Bull 43:111–118
Clarke A, Morris DJ (1983) Towards an energy budget for krill: the physiology and biochemistry of Euphausia superba Dana. Polar Biol 2:69–86
Denys CJ, McWhinnie MA (1982) Fecundity and ovarian cycles of the Antarctic krill Euphausia superba (Crustacea, Euphausiacea). Can J Zool 60:2414–2423
Ettershank G (1983) Age structure and cyclical annual size change in the Antarctic krill, Euphausia superba Dana. Polar Biol 2:189–193
Fowler SW, Small LF, Keckes S (1971a) Effects of temperature and size on moulting of euphausiid crustaceans. Mar Biol 11:45–51
Fowler SW, Benayoun G, Small LF (1971b) Experimental studies on feeding, growth, and assimilation in a Mediterranean euphausiid. Thalassia Jugosl 7:35–47
Hartnoll RG (1982) Growth. In: Abele LG (ed) The biology of Crustacea, vol 2. Academic Press, New York London, pp 111–196
Ikeda T (1984) Development of the larvae of the Antarctic krill (Euphausia superba Dana) observed in the laboratory. J Exp Mar Biol Ecol 75:107–117
Ikeda T (in press) Sequences in metabolic rates and elemental composition (C, N, P) during the development of Euphausia superba Dana and estimated food requirement during its life span. J Crustacean Biol
Ikeda T, Dixon P (1982a) Observations on moulting in Antarctic krill (Euphausia superba Dana). Aust J Mar Freshw Res 33:71–76
Ikeda T, Dixon P (1982b) Body shrinkage as a possible overwintering mechanism of the Antarctic krill, Euphausia superba Dana. J Exp Mar Biol Ecol 62:143–151
Ikeda T, Mitchell AW, Carleton JH, Dixon P (1980) Transport of living Antarctic zooplankton to a tropical laboratory: a feasibility study. Aust J Mar Freshw Res 31:271–274
Ivanov BG (1970) On the biology of the Antarctic krill Euphausia superba Dana. Mar Biol 7:340–351
Kikuno T, Kawamura A (1983) Observations of the ovarian eggs and spawning habits in Euphausia superba Dana. In: Nemoto T, Matsuda T (eds) Proc BIOMASS Colloquium 1982. Tokyo Press, Tokyo, pp 104–121
Lasker R (1966) Feeding, growth, respiration and carbon utilization of a euphausiid crustacean. J Fish Res Board Can 23:1291–1317
Mackintosh NA (1967) Maintenance of living Euphausia superba and frequency of moults. Norsk Hvalfangst-Tid 56:97–102
Mackintosh NA (1972) Life cycle of Antarctic krill in relation to ice and water conditions. Discovery Rep 36:1–94
Makarov RR, Denys CJ (1980) Stages of sexual maturity of Euphausia superba Dana. BIOMASS Handbook Ser 11:1–11
Marr JWS (1962) The natural history and geography of the Antarctic krill (Euphausia superba Dana). Discovery Rep 32:33–464
Mauchline J (1977) Growth and moulting of Crustacea, especially euphausiids. In: Anderson NR, Zahuranec BJ (eds) Oceanic sound scattering prediction. Plenum Press, New York London, pp 401–422
Mauchline J (1980) The biology of mysids and euphausiids. Adv Mar Biol 18:373–595
Mauchline J, Fisher LR (1969) The biology of euphausiids. Adv Mar Biol 7:1–454
McWhinnie MA, Denys CJ, Parkin R, Parkin K (1979) Biological investigation of Euphausia superba (krill). Antarct J US 14:163–164
Morris DJ, Keck A (1984) The time course of the moult cycle and growth of Euphausia superba in the laboratory. A preliminary study. Meeresforsch 30:94–100
Murano M, Segawa S, Kato M (1979) Moult and growth of the Antarctic krill in laboratory. Trans Tokyo Univ Fish 3:99–106
Passano LM (1960) Molting and its control. In: Waterman TH (ed) The physiology of Crustacea, vol 1. Academic Press, New York, pp 473–536
Poleck TP, Denys CJ (1982) Effect of temperature on the molting, growth and maturation of the Antarctic krill Euphausia superba (Crustacea: Euphausiacea) under laboratory conditions. Mar Biol 70:255–265
Ricker WE (1973) Linear regressions in fishery research. J Fish Res Board Can 30:409–434
Ross RM (1982) Energetics of Euphausia pacifica. 2. Complete carbon and nitrogen budgets at 8° and 12° C throughout the life span. Mar Biol 68:15–23
Sameoto DD (1976) Respiration rates, energy budgets, and molting frequencies of three species of euphausiids found in the Gulf of St. Lawrence. J Fish Res Board Can 33:2568–2576
Zaika VE (1973) Specific production of aquatic invertebrates. Wiley and Sons, New York, 154 pp
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Ikeda, T., Dixon, P. & Kirkwood, J. Laboratory observations of moulting, growth and maturation in Antarctic krill (Euphausia superba Dana). Polar Biol 4, 1–8 (1985). https://doi.org/10.1007/BF00286811
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00286811