Re: NANFA-- [Fwd: BOUNCE Message too long (>24000

tony (
Sun, 18 Jun 2000 19:39:18 +0700

A few questions about this:
1] How does the trematode get to the catfish? Via eating the snail, eating snail
droppings, or the parasite leave the snail and actively get into the catfish? If
the black carp eat snail with parasite won't it be infected or become the host and
become inedible?
2] Aren't there other NA fishes [bullheads, buffalos, suckers, perches, etc.] or
turtles or birds that can eat snail? Isn't reducing the number of small snail
enough to reduce the parasite problem? Aren't there other snail eating nonnative
fishes that find it hard to overwinter or breed in the Mississippi? eg. carp of
the genus Probarbus [tropical, required clear running water and gravel bed with
free silt to spawn], etc.


> Those in favor of having the option to use black carp gave the following
> arguments: First, there is no known therapeutant for the trematode and
> chemicals that control the snail populations are not FDA approved for use in
> foodfish. So currently, the black carp is the only known method of complete
> snail control for the trematode in question. While many argue that there are
> native species such as the redear or shellcracker sunfish which are capable
> of controlling snail populations, research has demonstrated that redear
> sunfish do not adequately control snail populations in ponds. Redear avoid
> snails with hard shells and their mouth gape size limits the size of snail
> they can consume.
> The black carp is the only fish species that is morphologically designed to
> crush snails with hard shells and has an adequate gape size.

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