Early life development of brown trout (Salmo trutta) eggs under temporary or continuous hypoxial stress : Effects on the gills, yolk sac resorption and morphometric parameters.
F. Massa et al., Early life development of brown trout (Salmo trutta) eggs under temporary or continuous hypoxial stress : Effects on the gills, yolk sac resorption and morphometric parameters., B FR PECHE, (355), 1999, pp. 421-440
Citations number
28
Categorie Soggetti
Aquatic Sciences
Journal title
BULLETIN FRANCAIS DE LA PECHE ET DE LA PISCICULTURE
Ecological studies on oxygenation in redds in salmonid streams suggest that
the egg-to-fry survival strongly depends on oxygen supply at key stages of
development. This probably results in an increased eggs mortality. Thus tw
o experiments have been carried out to test the effects of temporary or con
tinuous hypoxial stress on early life development of brown trout (Salmo tru
tta) eggs. Survival, growth, hatching and yolk-sac resorption dynamics were
analysed as well as branchial development after hatching in oxygenated and
deoxygenated (3 mg/l at a 300 ml/min water flow) conditions.
The results show that this oxygen concentration is not lethal for the embry
os at hatching. However sublethal effects are observed when hypoxial stress
is applied three weeks after fertilisation : hatching time is delayed, ale
vins are shorter, water content and yolk-sac conversion rate are lower than
the ones from the control. More pronounced effects are observed under cont
inuous hypoxic condition and higher mortalities are counted after hatching
and until yolk sac resorption. This is probably due to limited respiratory
exchanges linked to a reduced development of the gills.