RE: NANFA-- snorkeling with satinfins

Hoover, Jan J ERDC-EL-MS (HOOVERJ_at_wes.army.mil)
Mon, 2 Jul 2001 09:45:44 -0500

>>>...Cyprinella exhibit another reproductive
behavior that may be unique to the genus -- mock solo spawning, or the solo
run. In mock solo spawning, dominant nuptial males go though the motions of
spawning -- cruising over crevices, vibrating, undulating, holding their
fins erect<before actual spawning occurs. Three possibilities may explain
this behavior. Males could be testing the suitability of the crevice....<<<

This might include testing the crevice for appropriate water velocity. If
velocity is too fast, eggs may not be fertilized or could be swept away.
Too slow, and they may become covered with silt or suffocate. This topic
was studied by John Baker and Jack Killgore in a Ferguson flume (Baker,
J.A., K.J. Killgore, and S.A. Foster. Population variation in spawning
current speed selection in the blacktail shiner, C. venusta. Env. Biol.
Fish. 39: 357-364.). As a species, C. venusta spawned most often in crevices
with water velocities of 30 cm/s. Different populations, though, were
fine-tuned to local hydraulic conditions. C. venusta from areas with lower
stream flow (discharge) were more likely to use slower water velocities
(although populations from streams with a wider range of streamflow used a
narrower range of velocities).

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