to literature data (Kasumyan
& Døving, 2003;
Isaeva 2007), sucrosa as gustatory stimulus is indifferent for most of cyprinid
(Cyprinidae) fish such as carp, Cyprinus
carpio, tench Tinca tinca, bitterling Rhodeus sericeus amarus, lake bleak Leucaspius delineatus, crucian Carassius carassius, goldfish Carassius auratus, chub Leuciscus
cephalus, European minnow Phoxinus
phoxinus and bream Abramis brama,
in the experiments with the agar-agar pellets.
gustatory stimulus is only positive for roach Rurilus rutilus, grass carp Ctenopharyngodon
idella as well as for guppy Poecilia
reticulata (Poeciliidae) (Kasumyan & Døving,
2003) which eat the most large amount of vegetable food.
field experiments described below, we have tested the attractiveness of sucrosa
for cyprinid fish.
unfermented wheat bran with sucrosa (10 %) and without sucrosa were mixed with
the pure dry grey clay in proportion 1:1 or 1:2, depending on the clay
pastiness. Both mixes were rolled into the balls (3 cm diameter) and dried in
air within 12 hours. Then dry balls (that had the same color) were strung on
the lines (0,25 mm) ended by the small button like stoppers (15 mm diameter),
with marks to distinguish them.
with the two compared balls were tied (25 cm between centers of the balls) to
bar placed above the water
with the help of two racks. Narrow channels (40-50 cm width) in the shallows between
macrophytes (usually water lily, Nuphar
lutea, and pondweeds Potamogeton
spp.) were selected. Balls went
down to the depth of about 5 cm, to attract roach and other top
dwelling fish, or about 30 cm, to attract crucian and other bottom dwelling
the surface tests, mainly juvenile roach, R.
rutilus, rudd, Scardinius
erythropthalmus, as well as juvenile and adult river bleak, Alburnus alburnus, were attracted. In
lentic waters, lake bleak, L. delineatus, occured instead of
river bleak. In the bottom tests, mainly juvenile crucian, C. carassius, tench, T.
tinca, as well as juvenile and adult bitterling, R. sericeus amarus, (in areas with the sandy bottom) were
Roach, rudd and bitterling actively ate (in June) green algae.
After immersion into the water, clay balls with sweet and savorless wheat brans were beginning to crumble with bran particles
and attract fish. The fish were biting and destroying
the balls. So, the first touch of fish to one of the
balls and the destruction of the most attractive ball first were used as
criteria for statistical estimations.
tests of compared balls were carried out within one session. No preferences to
sweet or savorless brans were obsereved (sign test), including roach. Both balls
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