Re: NANFA-- Mystery Fish Communication

Bruce Stallsmith (
Thu, 01 Mar 2001 10:19:37 -0500

The "lucky stones", or otoliths, are bones in fishes' heads encased in a
membrane system and fluids that allow the fish to orient itself in 3D space;
this is equivalent to the semicircular canals in our ears. Otoliths (ear
stones) also function as pressure and sound receptors. They're an
increasingly studied structure in fish because they also are sensitive
biochemical recorders, accumulating various isotopes that reflect where a
fish has been and what it has eaten as well as growing in a pattern that
allows a fish to be aged. Whether this fish is a drum or a tilapia it should
have had large, unmistakable otoliths whose shape would allow you to make an
ID. Geoff's observation that it must be an aquarium release is certainly
true if the fish is a tilapia; if it is a drum, there are murkier
possibilities. If a tilapia, we can only hope that it was alone because
they're such successful colonizers of new habitats.

--Bruce Stallsmith
Huntsville, AL

>From: Roselawn Museum <>
>Subject: Re: NANFA-- Mystery Fish Communication
>Date: Thu, 01 Mar 2001 08:41:19 -0500
>Hey Bruce
>What are the "lucky stones" Shawn is referring to in the message below?
>Steven A. Ellis
>Kennesaw, GA
>At 12:00 PM 2/28/01 -0500, you wrote:
> >Below is a message I received from Shawn who posted the pictures and
> >questions about the mystery fish. I had written to him saying that it was
> >our collective opinion that it's some kind of red drum and/or hybrid.
> >
> >--Bruce Stallsmith
> >---------------------------------------------------------------
> >
> >Hi Bruce :
> >
> >A red drum is something we haven't considered, although one of our
> >guesses is closely related - freshwater drum. A couple of things steered
> >us away from that answer though. First, the caudal fin of a freshwater
> >drum (sheepshead) is rounded, whereas the fish in question has an
> >indented caudal fin. Second, the mystery fish does not have that
> >steep sloped forehead typical of a freshwater drum, though it is
> >difficult to tell for sure because of the way the angler is holding it's
> >head. Third, this angler has caught freshwater drum before in Lake
> >Champlain, Vermont, and has always removed their "lucky stones"
> >as he called them - the otoliths. He told me that he tried to get the
> >lucky stones out of this fish (he also thought it was a sheepshead)
> >but couldn't find them. This would say to me that if a guy who
> >normally takes them out couldn't find them in a "drum" of this size,
> >it probably wasn't a drum.
> >
> >But, we could be wrong. At this point, it's the most plausible
> >identification so far. Freshwater drum are native to Lake Champlain,
> >a hop, skip and a jump away from Lake Bomoseen - and angler here in
> >Vermont are well known - for taking fish from one lake and putting them
> >in another - for kicks I guess !
> >
> >Thanks ! -- Shawn.

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