NEWS112
8
Luckily themajorityof specieswereunable
to become established and disappeared
again,while others (e.g. the RainbowTrout,
Oncorhynchusmykiss,
whichoriginates from
North America), were able to breed only
very locally without human assistance. But
the Eastern Crayfish
(Orconectes limosus
) is
an example of extremely successful
colonization by an alien species with dire
consequences for the native fauna. As this
crayfish, whichwas supposed to provide a
supply of edible crays inwaters where the
ecologically more demanding native
Sometimes for noapparent reason invasive
species transform back into harmless
componentsof the floraand fauna.Agood
example of this is theCanadian Pondweed
(
Elodeacanadensis
),aNorthAmericanplant
that in themiddle of the 19th century had
choked inlandwaterways to suchanextent
that they were virtually unnavigable. But
nowadays this plant has become a normal,
naturalized aquatic plant that no longer
causesanyharm.Such life formsare termed
neobiota (=”new life-forms”),divided into in
neozoa (new animals), neophyta (new
plants), and neomycetes (new fungi).
Neobiota is the term that should be used
insteadof ”invasive species”as themajority
of neobiota have no perceptible harmful
influenceat all,andeven those species that
do suppress and extirpate others are not
morally toblame. It isneither justifiablenot
ethically acceptable to treat them with
abhorrence or xenophobia. Unfortunately
thecurrentpoliticaldiscussiondemandinga
general import ban on all potentially
invasive species, has its origins in themire.
There is supposedlygeneral concern about
anything foreignandunknown.Andpeople
- such as serious aquarists and terrarium
keepers -who represent theopposingview,
are defamed as traitors and nest-foulers -
nothingnew there.
Webear the responsibility!
The RainbowTrout (
Oncorhynchusmykiss
) is one of themost important fishes inGerman aquaculture
andmany people think it is a native species. In reality the Rainbow Trout is a neozoon that can even
threatennative speciesona local basis.
species couldnot survive, is the carrier of a
deadly disease, crayfish plague, lethal to all
native crayfishes. The Eastern Crayfish is
immunetothedisease,andmerelycarries it.
Another crustacean, the Chinese Mitten
Crab
(Eriocheir sinensis)
arrived accidentally
in Europe around 1910 in its larval form, in
water used as ballast by cargo ships.To the
presentday itcontinues toexpand its range
withgreatsuccess,robbing fishermen'snets
bareandmakingholes indykesanddams.
TheEuropeanBitterling (
Rhodeusamarus
) is a splendidexampleof how stupidemotional judgment of
neobionts can be. Until a few years ago it was regarded as an endangered species, in need of
conservation, inaccordancewith theFFHguidelines,and collecting it for aquariummaintenancewas a
serious criminal offence. Nowadays it is known that it is actually an invasive species that first spread
through largepartsofGermanyasa regional neozoonat theendof the18thcentury,andhence should
actuallybe combatedunder current law.
Naturally we hobbyists also bear a heavy
burden of responsibility. Never, under any
circumstanceswhatsoever,shouldanycold-
water fishes,crayfishes,crabs,mussels,snails,
shrimps, or aquatic plants that have grown
too large or troublesome be released into
the wild. The same applies to reptiles and
amphibians.There are already import bans
on theAmericanBullfrog (
Ranacatesbeiana
or
Lithobates catesbeianus
) and the Red-
Eared Turtle (
Trachemys scripta elegans
),
because these animals were released by
irresponsible idiots, resulting in local feral
populations.
If youhave animals that you canno longer
keep for valid reasons, andwhich you can't
re-home, feed to other livestock, or eat
yourself,and ifnoanimal refuge isprepared
