NANFA-- Re: nanfa V1 #1351

Dave McNeely (
Wed, 31 Jul 2002 09:44:09 -0500

Rough silverside = _Membras martinica_. It is essentially marine, but
occurs in estuaries, and there is a population in the Rio Grande as far
upstream as Anzulduas Dam at Mission, Texas (some 100 river miles miles from
the Gulf). The common name arises from the scalloped edges of the scales,
which give it a sandpapery feel. Though the fish is marine, I am not sure
that the Rio Grande population is introduced, but rather may be a part of
the general phenomenon of the lower Rio Grande fauna becoming made up more
and more of euryhaline species from the Gulf as estuarine conditions have
migrated upstream with reduced water flow. Of course, this population has
now been cut off from the Gulf, since the flow level of the Rio Grande is so
low that it fails to reach the Gulf of Mexico, similarly to the Colorado of
Grand Canyon fame. Where has the water gone? Irrigation and evaporation,
mostly, due to large reservoirs upstream in the U.S. and Mexico and
largescale farming. And the irrigation return is much saltier than the
water that is taken out.

Bob Edwards, of Pan American University, and Doyle Mosier of the Texas Water
Resources Commission, know more about the _Membras_ population than anyone
else. I think the fish is included in Hubbs, Edwards, and Garrett's Texas
checklist (which includes keys), published by the Texas Academy of Science.
However, in my marvelous organization sometimes called an office, I can't
lay hands on my copies right now.

Dave McNeely

> Date: Tue, 30 Jul 2002 14:57:43 -0500
> From: "Denkhaus, Robert" <>
> Subject: NANFA-- Anyone ever heard of...
> Going through a list of Texas freshwater fish species the other day, I
found a
> reference to "Rough Silverside". None of the species listed included
> Latin names so I had been checking those that I was not familiar with. I
> can't find anything that mentions any silverside other than inland, brook,
> waccamaw. Has anyone heard of this common name before? And if so, can
> put a Latin name to it?
> Thanks!!
> Rob Denkhaus
> Fort Worth Nature Center & Refuge

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