Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 4

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  Rhithropanopeus harrisii
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
EN
The American panopeid crab species Rhithropanopeus harrisii (Gould, 1841) is listed as an non-native species in European waters. In Poland, it occurred in the 1950s at two sites at the Baltic Sea coast, the Dead Vistula River (DVR) and the Vistula Lagoon (VL). Almost 50 years later, two additional populations were identified in the Gulf of Gdańsk (GG) and its inner part, Puck Bay (PB). In the present study, we sequenced and analyzed part of the mitochondrial cytochrome oxidase subunit I gene of the four Polish populations of R. harrisii in order to assess their genetic diversity and connectivity. The analyzed sequences of a length of 989 base pairs revealed eight different haplotypes. The highest number of haplotypes (n=6) was observed in the population from GG, whereas the lowest (n=3) in VL. The most common haplotype was recorded in 37% of the analyzed individuals. Pairwise ΦST values were mostly non-significant, with the exception of the comparison between DVR and VL (ΦST = 0.267; P < 0.05) and between PB and VL (ΦST = 0.194; P < 0.05), indicating a restricted gene flow or different sources of colonization.
EN
Rates of physiological processes and bioenergetics of the Harris mud crab Rhithropanopeus harrisii were determined during a 7-day experiment on adult males (mean wet weight 0.83 ± 0.16 g) exposed to temperatures of 15°C and 20°C (S = 7). The results show that the change in temperature by 5°C caused detectable changes in locomotor activity, food consumption and faeces production and significant (p < 0.05) changes in metabolic rates. Food assimilation efficiency and the ammonia excretion rate did not change significantly (p > 0.05). The energy expended on metabolic processes was similar at both temperatures (15°C and 20°C) and amounted to 17.7 ± 6.4% and 16.7 ± 4.3% of the assimilated energy, respectively. Similar values were obtained for net production efficiency K2 (P/A) at 15°C and 20°C, i.e. 80.4 ± 22.4% and 82.9 ± 9.7%, respectively. The amount of energy available for production was 2-fold higher at a temperature of 20°C than at 15°C and amounted to 103.69 ± 25.61 and 206.40 ± 20.76 J d−1g−1 wet wt, respectively. The results show that from the bioenergetic point of view, higher experimental temperature is more “profitable” for adult R. harrisii specimens because it provides better conditions for the growth and reproduction.
EN
The aim of this study was to determine the occurrence, spatial distribution and abundance pattern of the Harris mud crab Rhithropanopeus harrisii in the Gulf of Gdańsk (southern Baltic Sea). Between 2006 and 2010, this species was found at 69 out of 129 sampling stations, at depths from 0 to 20 m. Two main aggregations of the Harris mud crab were established: (1) in Puck Bay (max. density 19 indiv. 100 m-2) and (2) in the Gdynia and Sopot area (max. density 5 indiv. 100 m-2). 920 specimens were collected during the whole sampling period: 150 juveniles, 370 females and 400 males. The minimum measured carapace width was 1.96 mm, the maximum 21.40 mm (mean 9.03 ±4.11 mm).
EN
The mud crab is the only non-indigenous xanthid encountered in the River Odra estuary. In 2007-2008, the crabs were collected, using fish traps, to determine sex and to follow variations in individual weight and carapace length and width over a year. Sex-dependent differences in the crab morphometry were studied as well. The largest catch was that obtained in September (23.48% of the total number of 264 individuals) and October (31.82%). Male crabs accounted for 56.44% of the total number; males dominated in autumn (September-December) and spring (March, May, June) catches. Males showed significantly wider carapaces (16.81 š3.98 mm; range: 5.60-22.90 mm) and mean individual weight (2.15 š0.94 g; range: 0.15-3.93 g) than females (mean carapace width of 15.05 š3.33 mm; range: 5.30-19.80 mm, and mean individual weight of 1.47 š0.60 g; range: 0.13-2.56 g). Of the 11 morphometric characters analyzed, expressed in relative values (%), related to the carapace width, males showed significantly larger claw dimensions (CHL1, CHW1, CHH1, CHL2, CHW2, CHH2) and smaller abdomen widths (AW).
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.