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Spiny-cheek crayfish Orconectes limosus (Rafinesque, 1817) on its way to the open coastal waters of the Baltic Sea

Szaniawska A., Dobrzycka-Krahel A., Jaszczołt J.

Oceanological and Hydrobiological Studies

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2017

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Vol. 46, No. 4

451--463

EN

The aim of this work was to assess the adaptive capabilities of the spiny-cheek crayfish Orconectes limosus (Rafinesque, 1817) in the open coastal waters of the Baltic Sea. The results could help to predict the likely further expansion of this species and its colonization of brackish waters. The following aspects were discussed in the paper: the occurrence of the species in the Polish coastal zone of the Baltic Sea, the plasticity demonstrated in the body size of individual crayfishes, food preferences, hemolymph osmolality and reproduction in waters of different salinities, which enable the species to colonize brackish waters. In the Vistula Lagoon (salinity 2-3 PSU), where the population of O. limosus is stable, the length of individuals ranged from 77 to 118 mm. These crayfish mostly fed on fodder; the second and the third food preferences were crayfish abdominal muscle and green algae. O. limosus is a hyper-regulator in freshwaters and at low salinities (up to 13 PSU), and a hyporegulator at higher salinities (14, 21, 28, 35 PSU). Laboratory studies showed that the embryonic development of O. limosus at salinities of 3 and 7 PSU was normal and a high level of reproductive success was achieved. Salinity of 3 PSU is more favorable for the development of juveniles than 7 PSU. It seems to be just a matter of time before this crayfish starts to form populations in the brackish, coastal waters of the Baltic Sea.

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Range extension of Dikerogammarus villosus (Sowinsky, 1894) in Poland (the Baltic Sea basin) and its ability to osmoregulate in different environmental salinities

Dobrzycka-Krahel A., Melzer M., Majkowski W.

Oceanological and Hydrobiological Studies

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2015

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Vol. 44, No. 3

294--304

EN

The paper reports the range extension of the Ponto- Caspian gammarid Dikerogammarus villosus (Sowinsky, 1894) and the first occurrence of this species in new areas of the Polish part of the Baltic Sea basin: the Śmiała Vistula and the Vistula Lagoon. The studies additionally determine the osmoregulatory ability of the species under laboratory conditions within the salinity range of 2-22 PSU. Determination of the osmoregulation of the species shows that D. villosus is a hyperregulator at given experimental salinities and can function in a wide range of external salinities so it is potentially able to colonize various water bodies. Osmoregulatory capacity, which is an indicator of organism’s efforts to regulate the concentration of its body fluids, shows that for individuals from the Gulf of Gdańsk, 6 PSU is the best tolerated salinity. Osmoregulatory capacity is the lowest at this salinity value. The range extension and potential osmoregulatory abilities of the species to spread to other waters are discussed in the context of pollution levels given in the literature with reference to the habitat and sensitivity of the species to e.g. fluoride and cadmium toxicity.

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The effect of hypoxia and anoxia on osmotic concentrations of Corophium volutator (Pallas) from the Gulf of Gdańsk

Dobrzycka-Krahel A., Szaniawska A.

Oceanological and Hydrobiological Studies

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2005

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Vol. 34, No.1

99--109

EN

The aim of the investigations was to determine the effect of hypoxia and anoxia on the osmoregulation of Corophium volutator. The experiments were performed at salinities of 3.0, 6.6,15.0, and 25.0 PSU in conditions of hypoxia (saturation = 30% O2) and anoxia at a constant temperature of 10°C. Control experiments in aerated water were conducted simultaneously. Hypoxia (saturation = 30% O2) had no statistically significant effect on the osmoregulation of C. volutator after either 6 h or 48 h. However, after 6 h it did lower the osmotic concentration slightly. After 6 h anoxia had no effect on osmoregulation, but no subsequent effects of this factor (after 24 and 48 h) were detectable due to high animal mortality. Anoxia also had no effect on osmoregulation after 24 h at salinities of 15.0 and 25.0 PSU or 48 h at 15.0 PSU.

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Noding in Cyprideis torosa and its causes

Keyser D., Aladin N.

Studia Quaternaria

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2004

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Vol. 21

19-24

EN

The Ostracod Cyprideis torosa develops nodes on its calcified carapace in brackish waters and is therefore widely used in paleontology as a marker for lower saline waters. The formation of nodes in lower saline waters was investigated with SEM and TEM analyses and micro-cryoscopic measurements of the inner osmoregulation. Noding is considered a failure in osmoregulation, which causes the pillars connecting the inner and outer epidermal cell layer to rupture during the molting process. As a result, the still flexible shell develops protrusions, which then persist as nodes after subsequent calcification.