E. Gisbert et al., Behavioural modifications in the early life stages of Siberian sturgeon (Acipenser baerii, Brandt), J APP ICHTH, 15(4-5), 1999, pp. 237-242
Citations number
26
Categorie Soggetti
Aquatic Sciences
Journal title
JOURNAL OF APPLIED ICHTHYOLOGY-ZEITSCHRIFT FUR ANGEWANDTE ICHTHYOLOGIE
Behavioural modifications of Acipenser baeri were studied during early onto
geny at 18 degrees C by means of specific tests and general observations. D
uring A. baeri ontogeny, several different periods could be clearly disting
uished by behavioural patterns. From hatching to 3 days post hatch (p.h.),
specimens exhibited swimming-up and drift behaviour. A transition from a pe
lagic to benthic behaviour occurred between 4-5 days p.h. and specimens wer
e positively rheotactic. At 7-8 days p.h., prelarvae aggregated into school
s of different shapes. During prelarval development, specimens were positiv
ely phototactic, preferred white bottoms and did not show any preference fo
r bottom concealment. Between 9-10 days p.h. coinciding with the onset of t
he exogenous feeding, larvae were active bottom swimmers, schooling behavio
ur disappeared and larvae dispersed. During early ontogeny, changes in body
coloration were observed among those specimens who swam over bottoms of di
fferent brightness and during the day/night cycle. From 9 to 12 days p.h.,
larvae were positively phototactic, denied bottom cover and showed preferen
ce for white substrates. At 13 days p.h., the percentage of fish exhibiting
positive phototactism, preferring open to concealed bottom habitats and wh
ite bottoms started to decrease, while at 20 days p.h. specimens showed a c
lear preference for bottom concealment and black and greyish bottoms. The s
ignificance, use and evolution of the former behavioural patterns is deeply
discussed.