Re: NANFA-L-- Skewed Sex Ratio in Shiners?

Bruce Stallsmith (
Thu, 18 May 2006 13:19:10 -0400

The single easiest way to prejudice the collection for a species with adults
ranging from 28-55 mm long is the use of a coarse seine. We were using a a
fine seine with 1/4" mesh, which lets many YOY through but, as far as we
observed, no sexable adults. A study of the Ozark minnow, Dionda nubila, by
Glazier & Taber in 1980 found a significant female skew, but they attributed
that to the use of coarse seines during part of their field collection, so
that the smaller males could slip through the net; they didn't report the
exact mesh of their seine(s).

Other studies reporting sex skew are Burr & Mayden (1981) with Notropis
chihuahua, with males being more common, and Dahle (2001) with N. topeka,
finding that females made up about 60% of Age-1 and Age-2. Many more studies
on different Notropis and Cyprinella report little or no skew. So I
dunno..... it could be just a statistical fluke, or maybe there's something
interesting with burrheads. All I have to do is go back out to various
creeks, catch a bunch of burrheads, and determine the sex; right? And then
try to figure out what it means.

--Bruce Stallsmith
no burrheads right along the Tennessee
Huntsville, AL, US of A

>From: Bob Bock <>
>To: Bruce Stallsmith <>,
>Subject: Re: NANFA-L-- Skewed Sex Ratio in Shiners?
>Date: Thu, 18 May 2006 12:05:01 -0500 (CDT)
>No explanations here, Bruce, just a question:
>Are you sure that your collecting method isn't preselecting for one gender
>over the other?
>Years ago, when I was angling for longear sunfish and bringing them home, I
>noticed that I had more males and females. My thinking-in-the time was
>that since males were a little more agressive than females they tended to
>get to the bait first.
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