No, it's not the only stress but it is a stress that works with other
stresses.
The vermillion darter exists in one stream in suburban Birmingham, Alabama.
So far so good, but it's beautiful and people could easily take some and
stress the population. It's federally Endangered but vulnerable to habitat
alteration, random swings in population, and even collecting a few would
measurably increase the risk of extinction.
The watercress darter, also in the suburban Birmingham, AL, area, exists in
a few streams but faces that same threats as the vermillion from an
expanding metro area. Also federally Endangered.
The rush darter, one population in suburban Birmingham, AL, right on a strip
mall road in its own spring. Another population or two live 50 km away in a
National Forest. It's extremely localized in spring runs and any collecting
of this listed species would have a measurable harmful effect.
By some miracle all of the above species still exist in the wild. Collecting
didn't drive them to extinction, although F. julisia faced some serious
threats from that. But with only one or a handful of populations, even
taking 5 or 6 individuals could be catastrophic. Nobody here would disagree
with that statement, maybe, but to destroy a local population you don't have
to collect every single individual. Even a few taken can destabilize a
population over several generations in tandem with other stresses.
--Bruce "where are my darters?!?" Stallsmith
Huntsville, AL, US of A
>From: Steffen Hellner <steffen_at_hellner.biz>
>Reply-To: nanfa_at_aquaria.net
>To: <nanfa_at_aquaria.net>
>Subject: Re: NANFA-- Bluenose shiner news
>Date: Wed, 17 Sep 2003 23:33:14 +0200
>
>Very optimistic, though. What species have been protected from extinction
>(by prohibiting collecting)? The Desert Pupfish never were threated by
>collecting, they are threatened by destruction of their habitats,
>introduction of alien species and lowering water levels. Only C. diabolis
>could be collected off completely because of its single habitat. But even
>then the deposited eggs would stay and within a shorter time many fish will
>be present again - it has no food concurrents and no predators in its
>habitat. In Mexico many species are extinct already because water levels
>were dropped until their biotopes dried up completely, the rest by
>invaders.
>NONE because of collections, not a single one! Same with Crenichthys spp.,
>Cualac tesselatus, Megupsilon aporus. It4s industry, agriculture of
>overpopulation. And Megupsilon would already be gone if not aquarists would
>breed this difficult, small, not very attractive species.
>
>Got another example?;-) E.g. the pilgrim dove, the cypress parrot. Species
>which lived by the millions and have been eradicated without sense. The
>Bison escaped at last chance. What about lynx, silver lion a.s.o, a.s.o.
>Even the Blue Parrot from Brazil (Cynopsittaca spixi) was not brought close
>to extinction by hobbyists, though the last pair was stolen out of a
>natural
>reserve, but by habitat deminishing. There are many times more C. spixi in
>captivity than in the wild (in Brazil estimated 11 males and one single
>female - which came from a private breeder or zoo, I am not sure about
>that).
>
>I could go on mention examples for hours. And won4t find one against it.
>
>Steffen
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