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1

Morphometrics, fecundity, density, and feeding intensity of the spinycheek crayfish, Orconectes limosus (Raf.) in natural conditions

100%
Chybowski L.
Archives of Polish Fisheries
|
2007
|
tom 15
|
nr 3
The subject of the study was three populations of spinycheek crayfish, Orconectes limosus (Raf.) from lakes Staw Płociczno, Dgał Wielki, and Hańcza. The aspects of the spinycheek crayfish studied were the morphometric characters of females and males, individual absolute fecundity, sex ratio, size structure, density, biomass, and feeding intensity in an annual cycle. It was determined that the body proportions of males in forms I and II differed significantly, while the body proportions of female spinycheek crayfish were similar to those of form II males but different from the body proportions of form I males. The crayfish investigated in the current study had a lower individual absolute fecundity than did spinycheek crayfish of the same body weights from other Polish basins. The crayfish daily food ration exhibited a very strong relationship with the stomach fullness index and water temperature. The empirical formula of this relationship (ln Rd P = 0.397 + 0.094 t + 0.614 ln If) permitted estimating the daily food ration. The crayfish fed most intensely from the May to October period, during which they consumed in excess of 80% of their annual ration. The primary dietary component of the spinycheek crayfish was plant matter. Annually, the crayfish population consumed barely 0.27% of the wet weight of the aquatic vegetation in its range of occurrence.
2

Drapieżnictwo ryb na jajach płoci

100%
Chybowski L.
Komunikaty Rybackie
|
1991
|
nr 3
3

Absolute fecundity of two populations of signal crayfish, Pacifastacus leniusculus (Dana)

100%
Chybowski L.
Archives of Polish Fisheries
|
2013
|
tom 21
|
nr 4
4

Ichtiofauna górnego odcinka Czarnej Hańczy (zlewnia Niemna, północno-wschodnia Polska)

63%
Chybowski L., Bialokoz W.
Komunikaty Rybackie
|
2013
|
nr 6
The composition and structure of the ichthyofauna of the upper course of the Czarna Hańcza River (Nemen River basin northeast Poland) and changes in it since 1993 were studied. Fifteen fish species belonging to five reproduction ecology guilds were confirmed to occur currently in the river. The number of fish species occurring at given sites increased as the width of the river increased, while the share of rheophilous species increased with increasing river slope.
5

Intensywnosc i efektywnosc odzywiania sie wylegu pstraga teczowego karmionego pasza sztuczna

63%
Bialokoz W., Chybowski L.
Komunikaty Rybackie
|
1992
|
nr 2
4-7
6

Histological analysis of the annual cycle of gonad development in the male spin-cheek crayfish Orconectes limosus Raf.

63%
Chybowski L., Juchno D.
Archives of Polish Fisheries
|
2002
|
tom 10
|
nr 2
Histological analyses were conducted of the annual cycle of male gonads of spiny-cheek crayfish Orconectes limosus Raf. Although changes in the male gonads throughout the year are clearly evident, they are not uniform in all males. Spiny-cheek crayfish mate mainly in the autumn from September to November. After mating, the gonads of male crayfish can be divided into two groups according to their histological structure. In the first group there is an abundance of sperm in the gonads, while the testicular tubules in the second group are either empty or contain a small amount of sperm. This division remains until May. In May, the histological picture of the gonads is uniform, and there are either very few or no tubules containing sperm. In June O. limosus males occur in two forms. The histological pictures of first- and second-form male gonads do not differ. However, beginning in July and also in August and September, the gonads of first- and second-form males do differ. First-form male crayfish gonads contain more sperm than those of second-form males. From October onwards, all of the males are first-form, and primarily spermatids and sperm are visible in the gonads. The possibility that the spiny-cheek crayfish mates twice annually, once in autumn and again in spring, is discussed based on changes observed in the histological picture of the gonads.
7

Histological analyses of gonad development in female spin-cheek crayfish Orconectes limosus Raf.

63%
Juchno D., Chybowski L.
Archives of Polish Fisheries
|
2003
|
tom 11
|
nr 1
Histological analyses were preformed to investigate the annual cycle of the ovaries of female spiny-cheek crayfish Orconectes limosus Raf. (Crustacea). In May, the crayfish ovaries were filled mainly with oocytes in the initial stage of development (previtellogenic oocytes). The histological picture of the ovaries indicated the presence of empty follicles and mature oocytes undergoing resorption. In the summer months, the volume of the oocytes gradually increased and surplus substances material began to be synthesized (phase I or endogenous vitellogenesis). The histological picture of the ovaries in August was varied; some of them contained previtellogenic and vitellogenic oocytes in phase I, while others contained mainly oocytes in phase II of vitellogenesis when the cytoplasm fills with yolk and lipid globules. In fall, winter and spring the ovaries of crayfish O. limosus were filled mainly with oocytes in phase II of vitellogenesis; these were gradually increasing in volume. The annual gonadosomatic index (GSI) was calculated in the range of 0.41 to 5.83. The percentage of previtellogenic to vitellogenic oocytes prior to spawning was 23:77, and following spawning it was 70:30.
8

Ginace gatunki rakow w wojewodztwie suwalskim

51%
Bialokoz W., Chybowski L., Krzywosz T.
Zoologica Poloniae
|
1996
|
tom 41
|
nr Supl.
87-91
9

Ichthyofauna of the rivers in the Romincka Forest (Pregola River basin, northeastern Poland)

51%
Bialokoz W., Chybowski L., Krzywosz T., Traczuk P.
Archives of Polish Fisheries
|
2009
|
tom 17
|
nr 2
10

Rak pregowaty w wodach wojewodztwa suwalskiego

51%
Krzywosz T., Bialokoz W., Chybowski L.
Komunikaty Rybackie
|
1995
|
nr 2
8-11
11

Use of frozen zooplankton in the intense rearing of eurpean catfish [Silurus glanis l.] larvae

51%
Ulikowski D., Borkowska I., Chybowski L.
Archiwum Rybactwa Polskiego
|
1998
|
tom 06
|
nr 1
97-106
12

Rak sygnalowy w Polsce - historia, stan obecny, perspektywy

51%
Krzywosz T., Chybowski L., Ulikowski D.
Komunikaty Rybackie
|
1995
|
nr 1
5-8
13

Wybiorczosc pokarmowa szczupaka wzgledem troci jeziorowej, ploci i okonia w warunkach stawowych

51%
Szczepkowski M., Szczepkowska B., Chybowski L.
Komunikaty Rybackie
|
1998
|
nr 1
6-7
14

Podchow wylegu troci jeziorowej na paszy Ecostart 17

51%
Szczepkowska B., Szczepkowski M., Chybowski L.
Komunikaty Rybackie
|
1998
|
nr 1
4-6
15

Podchow larw sielawy [Coregonus albula L.] na paszy sztucznej z dodatkiem 3,5,3'-trojjodotyroniny

51%
Mamcarz A., Poczyczynski P., Kozlowski J., Chybowski L.
Komunikaty Rybackie
|
1996
|
nr 2
19-21
16

Development of vitellogenic oocytes in ovaries of female reciprocal hybrids of rudd, Scardinius erythrophthalmus (L.) ans carp bream, Abramis brama (L.) under experimental conditions

51%
Kopiejewska W., TerleckiJ J., Chybowski L.
Acta Scientiarum Polonorum. Piscaria
|
2007
|
tom 06
|
nr 3-4
17

Harmful impact of filamentous algae (Spirogyra sp.) on juvenile crayfish

51%
Ulikowski D., Chybowski L., Traczuk P.
Archives of Polish Fisheries
|
2015
|
tom 23
|
nr 4
18

Cyclic development of sex cells in artificially bred rudd Scardinius erythrophthalmus [L.]

51%
Kopiejewska W., Terlecki J., Chybowski L.
Acta Scientiarum Polonorum. Piscaria
|
2004
|
tom 03
|
nr 1-2
19

Varied somatic growth and sex cell development in reciprocal hybrids of roach Rutilus rutilus [L.] and ide Leuciscus idus [L.]

51%
Kopiejewska W., Terlecki J., Chybowski L.
Archives of Polish Fisheries
|
2003
|
tom 11
|
nr 1
Body length and weight and the developmental stage of sex cells were determined in 1.5- and 3-year-old specimens of the F₁ generation of reciprocal hybrids of roach Rutilus rutilus and ide Leuciscus idus. Body length and weight and the developmental stage of sex cell varied in reciprocal hybrids of roach and ide. The hybrids obtained from crossing R. rutilus females with L. idus males (R. rutilus x L. idus) were larger than those obtained from crossing L. idus females with R. rutilus males (L. idus x R. rutilus) (P < 0.001). At the ages of 1.5 and 3 years the hybrids had a similar body length and weight to L. idus (P>0.05) and a greater body length and weight than R. rutilus (P<0.001). The hybrids of L. idus x R. rutilus were smaller than L. idus and larger than R. rutilus (P < 0.001). Two-thirds of the studied L. idus x R. rutilus hybrid females were sexually mature at age 3, and only one R. rutilus x L. idus hybrid female exhibited signs of cytological maturation. In the control samples, roach females reached sexual maturity, while ide females were immature. The testes of 3-year-old R. rutilus x L. idus hybrid males contained spermatogonia and spermatocytes, while those of L. idus X R. rutilus hybrid males most often contained spermatocytes. The ovaries of female reciprocal hybrids of R. rutilus and L. idus contained not only developing oocytes, but also sex cells which stopped developing at an early stage of gametogenesis. These constituted approximately 50-60% of the area of ovary sections in 13% of the studied females, while in other females they were observed singly. The results obtained indicate that rapid somatic growth exhibited by L. idus is inherited by hybrids to a greater extent through L. idus males than through females. The differences in achieving sexual maturity exhibited by the females of reciprocal hybrids of R. rutilus and L. idus suggest that male genomes may have an important impact on this process.
20

Attainment of sexual maturity by hybrids of rudd, Scardinius erythrophthalmus [L.] and carp bream, Abramis brama [L.] under experimental conditions

51%
Kopiejewska W., Terlecki J., Chybowski L.
Acta Ichthyologica et Piscatoria
|
2004
|
tom 34
|
nr 1
Background. In case of natural hybridisation of fish it is important to determine whether the hybrids attain sexual maturity and whether they can produce generation F2. The hybrids of rudd and carp bream, relatively frequent under natural conditions, have not been studied in the aspect of sexual maturity attainment. Materials and Methods. Histological examinations of gonads of 4-5 year old rudd and carp bream hybrids were carried out in experimental environments during the pre-spawning and spawning seasons of the parental species. Results. In development of oocytes the female hybrids of rudd and carp bream reached the stage of migrating nucleus and deterioration of the morphological structure of the nucleus. In case of male hybrids the presence of spermatids was confirmed. The stage of spermatozoa was not observed in case of hybrids of rudd and bream. In case of the control species (rudd) that stage was also not observed. It is possible that the lack of that stage was affected by the parameters of the culture environment. Nevertheless, the sexual products of male hybrids of rudd and bream as well as rudd were deposited. Conclusion. The studies show that the hybrids of rudd and carp bream may reach sexual maturity in the natural environments.
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