RE: NANFA-- phoxinus erythrogaster breeding

Mark (markb_at_columbus.rr.com)
Mon, 19 May 2003 22:03:24 -0400

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At 7:19 PM -0400 5/19/03, geoff wrote:
>While on the subject of phoxinus, I have a few northern red belly dace from
>Wisconsin. These fish are found in slower waters than the southern red
>belly dace. I have read that the northern dace breed in plant clumps, while
>I know the southern scatter eggs in gravel, especially in stoneroller nests.
>Are there morphologic differences between the northern and southern red
>belly dace?

Yes. While I don't know if it has any relevance to their breeding
behavior, the most obvious difference between the two is the position
of the mouth. P erythrogaster's mouth is slightly subterminal, with
the snout overhanging it _slightly_. P eos' mouth is terminal and
may slant slightly upward. There are surely variations on this from
population to population, but this is generally true in my
experience. The differences in breeding mode could be related to
differences in habitat. P erythrogaster usually lives in small
headwater streams with steady flow. These tend to be sparse on
vegetation and heavy on gravel areas. Versus P eos which tends to
live in clear lakes and quiet areas where submerged vegetation is
common and bare gravel is harder to find, or maybe would leave the
adults and fry more vulnerable to predation by larger fishes than in
shallow headwaters where large predators are limited. Yeah, I think
I've convinced myself of that :)

-- 
Mark
Ohio
USA
<))><
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