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Bohlen, J.


Similarities and differences in the reproductive biology of loaches (Cobitis and Sabanejewia) under laboratory conditions


Folia Zoologica 49 Suppl. 1: 173-178


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

 

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