Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 2

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
The aim of this study was to define an influence of water temperature on successful reproduction of burbot under the hatchery conditions. Research was conducted during four successive spawning seasons where wild spawners were used. In the first three years of study fish were kept in three different (natural) thermal conditions. In the fourth year it was confirmed that the highest efficacy of synchronization of the spawning could be reached only under controlled thermal regimes. That year one group of spawners was kept at 6℃ before spawning and then a sudden decrease of the temperature to 1℃ was applied. Restrictively controlled thermal regime during reproduction of burbot in captivity caused the most synchronous spawning of females (2 days-period) in contrast to control group (17 days-period) and even hormonally stimulated (4 days-period). Eggs survival in thermally manipulated group was very high (over 85% in the eyed-egg-stage). This research proved that manipulation of water temperature is the most important technique which should be applied in controlled reproduction of burbot and it is suggested that the temperature is the major factor during final maturation of burbot females. Also, confirmed the fact that incubation of burbot eggs in temperature over 5℃ causes its high mortality (100% in the eyed-egg-stage).
In this study the suitability of various feeds in mass rearing of burbot Lota lota (L.) larvae under controlled conditions was determined. During the rearing the fish were fed with: artificial fodder, live Artemia nauplii and decapsulated cysts of artemia. The experiment continued for 20 days and it was conducted from hatching of the larvae. The initial density of fish during rearing was 1000 individuals dm⁻³. Rearing water temperature was set at 12℃. The parameters such as: average body length and height of the larvae and survival after completion of rearing period, were recorded. The Artemia nauplii proved the most suitable for feeding burbot larvae during the initial rearing. Additionally, high mortality of larvae was recorded during the period of filling the swim bladder.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.