Regional Peculiarities of Bilogical State of Antarctic Krill Euphausia superba Dana in Shelf Waters of the South Georgia in June-August 2004
- Antarctic krill,
- modal group,
- maturity,
- sex,
- nutrition
- infection ...More
Abstract
The data collected in the shelf waters of the northern South Georgia allowed determining the morpho-physiological state of Antarctic krill (Euphausia superba) in the winter months of the Southern Hemisphere (June-August, 2004). The analysis of variation curves permit distinguishing three krill size groups: the first group is small krill (of modal size 32-40 mm), the second group consists of comparatively large crustaceans (of modal size 34-44 mm), and the third – large krill (of modal size 44-50 mm). Changeability of their distribution was found: on the north-western shelf small crustaceans prevailed (Group I). As the fishery was moving to the east the rate of juveniles decreased considerably, and the abundance of the second group krill increased. During winter krill groups of the same size had similar morpho-physiological state both on the north-western and north-eastern ground. The differences were recorded in the second half of the winter. They dealt with maturity stages of females and males: in June males and females were at I and II stages, and in July-August – at stages II and II-III, correspondingly. As it was before (2001-2003), among large krill individuals the affection of carapace soft tissues and its chitinous cover was found. The percentage of the affected krill on the north-western ground reached 7.5, and on the north-eastern one – 5.5.
References
- Latogurskiy, V.I. (1973). Osobennosti biologii krilia Euphasia superba Dana is raiona ostrova Yuzhnaia Georgia v lentiy i zimniy sezony 1969-70 gg. [Specifics of krill Euphasia superba biology from the region of the South Georgia Island in the summer and winter seasons of 1969-1970]. Trudy AtlantNIRO, 53, 135-150. (In Russian)
- Makarov, R.R. (1971). Nekotorye dannye o sostave populiacii i razmnozhenii Euphasia superba Dana [Some data on the population composition and multiplication of Euphasia superba Dana]. Okeanologia, 77, 85-92. (In Russian)
- Maslennikov, V.V., Soliankin, Ie.V., Spiridonov, V.A., & Sysoieva, M.V. (1983). K issledovaniu proishozhdenia osobey Euphasia superba Dana, vstrechaiuschihsia v vodah o.-va Yuzhnaia Georgia [To the study of the origin of the Euphasia superba Dana specimens occurring in the waters of the South Georgia Island]. Antarkticheskiy krill: Osobennosti raspredelenia i sreda. Moscow, Leg. i pisch. prom-t'. P. 74-85. (In Russian)
- Spravochnik nauchnogo nabliudatelia. Razdel 3 [A research observer's guide. Chapter 3]. (1997). ANTCOM, Hobart, Australia. (In Russian)
- Savich, M.S., & Zhuk, N.N. (2004). Rezul'taty issledovaniy biologicheskoi struktury populiacii krilia (Euphasia superba Dana, 1852) v vodah ostrova Yuzhnaia Georgia v iule-oktiabre 2001 goda [Results of the survey of the biological structure of krill (Euphasia superba Dana, 1852) population in the waters of the South Georgia Island in July-October 2001]. Ukrainian Antarctic Journal, 2, 138-144. (In Russian)
- Sysoieva, M.V., & Shevcov, V.V. (1980). Razmernyi sostav, biologicheskoie sostoianie i osobennosti raspredelenia Euphasia superba Dana u o-va Yuzhnaia Georgia oseniu 1977 g. [Size composition, biological state and specifics of distribution of Euphasia superba Dana near the South Georgia Island in the fall of 1977]. Biologicheskie resursy antarkticheskogo krilia. Trudy VNIRO. Kaliningrad. P. 146-167. (In Russian)
- Shevtsov, V.V., & Makarov, R.R. (1969). K biologii antarkticheskogo krilia [To the biology of the Antarctic krill]. Trudy VNIRO. Moscow. V. 66, 177-206. (In Russian)
- Ivanov, B.G. (1970). On the Biology of Antarctic krill (Euphasia superba Dana). Mar. Biol., 7(4), 340-351.
- Heywood, R.B., Eveson, I., & Priddle, J. (1985). The absence of krill from South Georgia zone, winter, 1983. Deep-Sea Res. A., 33(3), 369-378.
- Jazdzewski, K., Dzik, J., Porebski, J., Rakusa-Suszczewski, S., Witek, Z., & Wolnomiejski, N. (1978). Biological and population studies on krill near South Shetland Islands, Scotia Sea and Georgia in the summer 1976. Pol. Arch. Hydrobiol., 25(3), 607-631.
- Reid, K., Barlow, K.E., Croxall, J.P., & Taylor, R.I. (1999). Predicting changes in the Antarctic krill, Euphasia superba, population at South Georgia. Marine Biology, 135(4), 647-652.
- Watkins, J.L., Murray, A.W.A., & Daly, H.I. (1999). Variation in the distribution of Antarctic krill Euphasia superba around South Georgia. Marine Ecology Progress Series, 188, 149-160.