Folia Zoologica 49 Suppl. 1: 179-186 (2000)
Similarities and differences in the reproductive biology
of spined loach (Cobitis and Sabanejewia)
under laboratory conditions
BOHLEN J.
Abstract
Spined
loach from 12 populations (two Sabanejewia , one Iberocobitis,
two Bicanestrinia and seven Cobitis
s.str.) were bred under comparable conditions in aquaria. Both Sabanejewia
spread very small (diameter 1.0-1.2 mm), sticky eggs all over the aquarium,
while all Cobitis spawned into the
most dense vegetation. Eggs of Cobitis
s.str. and Bicanestrinia were large
(2.0-3.4 and 2.0-2.5 mm, respectively) and unsticky. The eggs of Iberocobitis
were intermediate sized (1.7 mm) and slightly sticky. Significant differences in
egg size were found between most species. Eggs diameter was correlated to size
of hatchlings (Spearman rank coefficient 0.85, p<0.001). The mean number of
eggs per spawning act ranged between species from 246 to 2058 and the number of
spawning acts per female from 1 to 18. In at least three species a change of
adult coloration during spawning occurred. Spawning behaviour was identical in
at least four species of Cobitis. The
largest differences in reproductive biology were found between genera and the
second largest between subgenera. Some characters were species-specific.
Consequently, features of reproductive ecology may characterise taxonomic units
of spined loach.
Key words: mating behaviour, spawning substratum, egg size, early life stages