Captive breeding programs of endangered fish species, such as the European
mudminnow Umbra krameri, are essential for population restoration. To improve
captive spawning and larvae rearing under controlled conditions, two
experiments were carried out. In the first, the spawning substrate preference
was tested in triplicate, where five different types of artificial surface
were provided for mudminnow pairs:(i)sand, (ii)artificial plants,
(iii)gravel, (iv)sand + artificial plants and(v)gravel + artificial plants.
All fish preferred the gravel + artificial plant combination, which indicates
that this type of surface could be the most appropriate for spawning in
captivity. In the second trial, three feeding protocols were tested in
triplicate under controlled conditions. In the first treatment fish were fed
exclusively with Artemia nauplii; in the second treatment fish were fed with
Artemiafor the first ten days then Artemia was gradually replaced with dry
feed; for the third group the transition period started after 5 days of
Artemia feeding. Although the survival rate of larvae could be maintained at
a high level in some of the feeding protocols, a strong decrease in the
growth rate was obvious in all diets containing dry food, which means that
live food is essential for the first three weeks of mudminnow larvae
rearing.
Ex situ protection of the European mudminnow (Umbra krameri Walbaum, 1792): Spawning substrate preference for larvae rearing under controlled conditions