Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: spawning site

Sortuj według:

Ogranicz wyniki do:

Preliminary field observations of lake trout (Salmo trutta m. lacustris L.) redd structure, and fry emergence in the upper Wda river system (northern Poland)

100%

Radtke G.

Archives of Polish Fisheries

2005

tom 13

nr 1

Some parameters of spawning redds and the emergence of lake trout fry were investigated at spawning areas in the upper Wda River system. Redds were located and selected in late fall 2003 and a few of their parameters were identified, i.e., dimensions, water velocity, and grain fraction content. The sand content varied in particular redds from 5.1 to 24.8%. Fry was captured with traps at five of the six observed redds. Trout emerged from late April until mid May when temperatures increased within the range of 11.0-16.0°C. The most numerous trout fry was observed in the two biggest redds, which had less sand and high water velocities.

Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik

Vimba Vimba vimba (L.) from the Rega River - support of natural spawning in 2004-2008 and the natural population

100%

Tanski A., Czerniejewski P., Keszka S., Pender R., Pilch E.

Baltic Coastal Zone. Journal of Ecology and Protection of the Coastline

2011

tom 15

The paper reports results of a study on the population of vimba in the Rega River aimed at localisation of the spawning sites and support of the natural reproduction by stocking. The spawning sites were localised with the help of electric catching and the coordinates were determined by GPS units. The fish caught to be used for artificial spawning (145 individuals) were measured (l.t. and l.c.) using an electronic calliper coupled with a PC unit. The sex of the fish was identified and on the basis of scale analysis the age and rate of length and mass increase were estimated. The backcalculation readings were made using the Rosa Lee method. The model of growth was established on the basis of the von Bertalanffy formula. Comparisons of groups of fish were drawn with the help of the nonparametric Mann Whitney U test. Correlations between variables were evaluated by analysis of regression, while the significance of the correlation coefficient was checked by t test. The rate of vimba mass increase was calculated using the modified von Bertalanffy formula was found to be described by Wt = 1215.103[1-e-0.133609(t+0.57322)]2.7559. The spawning sites of vimba localised in the Rega River section between Gryfice and Trzebiatow were concluded to be good sources of spawners for artificial spawning and the number of spawners caught in this section of the river ensures continuation of vimba restitution in the Rega River. The hitherto stocking measures aimed at restoration of vimba population have brought satisfactory results as evidenced by the age structure of the fish caught in the electric fishing in 2008.

Ograniczanie wyników

1 Archives of Polish Fisheries

1 Baltic Coastal Zone. Journal of Ecology and Protection of the Coastline

1 Czerniejewski P.

1 Keszka S.

1 Pender R.

1 Pilch E.

1 Radtke G.

1 Tanski A.

1 2011

1 2005

Wyniki wyszukiwania

Preliminary field observations of lake trout (Salmo trutta m. lacustris L.) redd structure, and fry emergence in the upper Wda river system (northern Poland)

Vimba Vimba vimba (L.) from the Rega River - support of natural spawning in 2004-2008 and the natural population