Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 8
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

The distribution and some aspects of the ecology of Euphausia crystallorophias, Euphausia frigida, Euphausia triacantha and Thysanoessa macrura are presented. The investigations in the Polish Sector "A" show that E. triacantha is the northernmost and E. crystallorophias the southernmost species. These two species occurred least frequently. T. macrura was the most numerous and most regularly distributed species in the region under investigations.

Go to article

Authors and Affiliations

Wojciech Kittel
Ryszard Stępnik
Download PDF Download RIS Download Bibtex

Abstract

In the plankton samples collected with a Bongo net besides Euphausia superba the following species of the Euphausiacea were found:. £. frigida, crystallorophias, E. triacantha and T. macrura. The most aboundant and most frequently caught species was T. macrura equally distributed throughout the research area. The species E. frigida also occurred regularly though in much smaller numbers. E. triacantha occurred sporadically, mainly in the western part of the research region, and E. crystallorophias only at two stations in the Bransfield Strait. Some aspects of the biology and ecology of the mentioned above species are presented in this study.

Go to article

Authors and Affiliations

Wojciech Kittel
Zbigniew Witek
Henryk Czykieta
Download PDF Download RIS Download Bibtex

Abstract

Euphausia superba and E. crystallorophias were the dominant species in the area studied, Thysanoessa macrura, E. jrigida and E. triacantha were also present. The abundance of krill was changing during the year; minimum occurred between March and August and maxima between December and February and from September till November. Age structure of three most frequently occurring species showed seasonal variations. The periods of development and Reproduction were different for T. macrura, E. erystallorophias and E. superba.

Go to article

Authors and Affiliations

Ryszard Stępnik
Download PDF Download RIS Download Bibtex

Abstract

In the investigated area, mass occurence of krill was observed in the vicinity of islands and the Antarctic Peninsula, in the waters above the shelf and shelfs slope. Small quantities of krill were found in the open oceanic waters. Immature individuals dominated close to the Antarctic Peninsula. Large, sexually mature kril dominated farther from the continent. Gravid females contributed little to the total populations. Krill of the largest size occured near the Palmer's Archipelago, and of the smallest size at the Antarctic Peninsula and the Elephant Island. It is likely that krill observed west and north of the Palmer Archipelago had been brought by currents from the Bellingshausen Sea. Krill in the Bransfield Strait originated probably from the mixing of populations carried by currents from the Weddell Sea and the Bellingshausen Sea.

Go to article

Authors and Affiliations

Norbert Wolnomiejski
Henryk Czykieta
Ryszard Stępnik
Hanna Jackowska
Download PDF Download RIS Download Bibtex

Abstract

In the investigated area krill occured in low abundance. It was recorded mainly above the shelf and above the continental slope close to the Palmer Archipelago and near the northern shores of Elephant Island. In the central part of the Bransfield Strait E. superba was caught in especially small quantities. In general krill of small size occurred, the size decreasing from the west to the east. Mature krill was dominan in the western part of the investigated area, whereas juveniles in the eastern part. Gravid females were caught very rarely.

Go to article

Authors and Affiliations

Henryk Czykieta
Wojciech Kittel
Zbigniew Witek
Norbert Wolnomiejski
Download PDF Download RIS Download Bibtex

Abstract

In the plankton samples, collected with a Nansen net in three water layers downwards to a depth of 500 m, larvae and eggs of Euphausia superba were found as well as the larvae of E. crystallorophias and E. frigida. Eggs of the species E. superba predominated and among the larvae most numerous were calyptopis I and metanauplius stages. Eggs and larvae of E. superba occurred in small quantities, mainly in Bransfield Strait. Larvae of E. crystallorophias were found in the southeastern part of Bransfield Strait. Metanauplius, calyptopis I and II stages were predominant. Larvae of E. frigida, mostly calyptopis I stage, were very scarce and occurred only at the stations located in Drake Passage.

Go to article

Authors and Affiliations

Zbigniew Witek
Wojciech Kittel
Download PDF Download RIS Download Bibtex

Abstract

In the planktonie material collected using a Nansen net (vertical hauls) larvae of two euphausiid species were found. The dominant and occurring in all stations were larvae of Thysanoessa macrura. Following larval stages were encountered: nauplius, metanauplius, calyptopis I and calyptopis II. The most numerous and occurring in the widest depth spectrum were calyptopes I. Only twice furcilia VI of Euphausia superba were found. The distribution of euphausiid larvae was influenced by the stratification and circulation of water masses in the investigated area.

Go to article

Authors and Affiliations

Wojciech Kittel
Download PDF Download RIS Download Bibtex

Abstract

Krill population structure was studied in Western Antarctic in austral spring and summer 1986/87. At the end of October and the beginning of November in the waters around Elephant Island the mean krill length was 44 mm and sexually mature specimens dominated. Juveniles were absent. In the Bransfield Strait the mean E. superba length was 43 mm. and males slightly overdominated females. The share of females with spermatophores and of immature females was higher than in the Elephant Island area. Juveniles were also not recorded. Krill was most diversified around Elephant Island in January; juveniles and females with ovaries filled with eggs were recorded. It was found that 84% of krill population was infested by ciliate protozoans (Apostomatida).

Go to article

Authors and Affiliations

Wojciech Kittel
Stanisław Rakusa-Suszczewski

This page uses 'cookies'. Learn more