Invasive cichlids in Tuscany, Italy

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Bojan Dolenc
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Invasive cichlids in Tuscany, Italy

Post by Bojan Dolenc » Sun Oct 10, 2010 11:04 am

Piazzini, S., Lori, E., Favilli, L., Cianfanelli, S., Vanni, S. & Manganelli, G. (2010). Invasion Note: A tropical fish community in thermal waters of southern Tuscany. Biological Invasions. 12 (9): 2959-2965. DOI: 10.1007/s10530-010-9695-x

Abstract:
In a small stream of southern Tuscany (Fossa Calda), fed by hot springs, we discovered a fish community dominated by tropical species, some of which have never previously been reported in Euro-Mediterranean natural freshwater environments.
The aim of our research was to ascertain whether the three most abundant and widespread species (Amatitlania nigrofasciata, Hemichromis sp. and Oreochromis niloticus) have become established.
Analysis of size class distribution and growth curves showed that the populations of these species are quite large and made up of juveniles, subadults and adults, as is the case in self-sustaining populations.
These fishes were probably released intentionally, since they are widely used in aquariums and aquaculture and their survival in Fossa Calda was possible because of the constant high temperature of thermal waters.
Spread to other streams seems unlikely. In fact, at some distance from the hot springs, where water temperatures are lower, populations of the tropical species were small.

http://www.springerlink.com/content/d3k5651720758784/
Change in habit, producing change of function, is the main cause of the production of change in living structure. F. Wood Jones (1953) Trends of life

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Re: Invasive cichlids in Tuscany, Italy

Post by nick a » Mon Oct 11, 2010 7:58 am

Intersting. As we all work to conserve endangered species.....Hemichromis species are quietly taking over the world.....which they'll rule over with the cockroach after we destroy ourselves :lol:

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Re: Invasive cichlids in Tuscany, Italy

Post by illustrator » Sat Oct 16, 2010 12:16 pm

even more interesting that it concerns 2 of the same species as in the austrian stream and the third is "shared" with a Slovenian thermal stream, despite the fact that an enormous diversity of species is available in trade. This probably means that the species most likely to be invasive in these streams are:

- species which breed easily in "beginners-aquariums"
- species which you can't sell offspring off
- and of those the meanest competitors ...

But these species are then also the most risky if they are released in tropical countries, so perhaps keeping these species should be discouraged worldwide ...

(I would add some livebearers and pleco's to these cichlids as "very risky")

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Re: Invasive cichlids in Tuscany, Italy

Post by SergeS » Wed Oct 20, 2010 9:22 am

So true. In Holland, there is apparently a population of Poecilia reticulata living in the stream where the cooling water exhaust of a large steelfactory is. They grow over 12 cm (4,5"!) in size and manage to survive through the - sometimes pretty cold - Dutch winters as the water is never too cold. I suppose they could even survive a season if they venture out too further, but during winter, any population that is too far away from their warm 'nest' will probably die so they are contained. I always wanted to see them myself, just out of curiosity, but there is no way I am getting in that water :)

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Re: Invasive cichlids in Tuscany, Italy

Post by Dan Woodland » Wed Oct 20, 2010 9:43 am

SergeS wrote:So true. In Holland, there is apparently a population of Poecilia reticulata living in the stream where the cooling water exhaust of a large steelfactory is. They grow over 12 cm (4,5"!) in size and manage to survive through the - sometimes pretty cold - Dutch winters as the water is never too cold. I suppose they could even survive a season if they venture out too further, but during winter, any population that is too far away from their warm 'nest' will probably die so they are contained. I always wanted to see them myself, just out of curiosity, but there is no way I am getting in that water :)
This same situation occurred in Texas some years ago where bait shops sold Mbuna as bait fish and as fisherman do, they tossed the "leftover" bait into the river below a power plant. Last I knew there is still a thriving population of African Cichlids.

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Re: Invasive cichlids in Tuscany, Italy

Post by SergeS » Wed Oct 20, 2010 4:29 pm

Nice. Wildcaught Malawi cichlids from Texas :lol:

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Re: Invasive cichlids in Tuscany, Italy

Post by sidguppy » Thu Oct 21, 2010 6:42 am

probably after all this time it's a batch of truly unholy hybrids; if you just dump a lotof different Mbuna's together you'll end up with something entirely new, unless you remove the fry.

they're lucky they didn't release Boulengerochromis fry :lol:

although it could have been worse if the baitfish were Asian cyprinids

as far as I know, many North american streams are completely overrun with Silvercarp, bighead carp and a long list of other Asian pests.
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Re: Invasive cichlids in Tuscany, Italy

Post by Bas Pels » Thu Oct 21, 2010 7:20 am

At least cichlids have the decency of dying when it gets too cold

Therefore most places where cichlids are liberated - both in Europe and in America - will be purified in winter. The exceptions? Florida, perhaps Texas and everywhere where heat is put into rivers - as long as this thermal pollution continues

I heard the above mentioned population of guppies has been destroyed this way - the steel factory put an heat exchanger on the waste water before releasing it 8)

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Re: Invasive cichlids in Tuscany, Italy

Post by illustrator » Thu Oct 28, 2010 11:47 am

SergeS wrote:So true. In Holland, there is apparently a population of Poecilia reticulata living in the stream where the cooling water exhaust of a large steelfactory is. They grow over 12 cm (4,5"!) in size and manage to survive through the - sometimes pretty cold - Dutch winters as the water is never too cold. I suppose they could even survive a season if they venture out too further, but during winter, any population that is too far away from their warm 'nest' will probably die so they are contained. I always wanted to see them myself, just out of curiosity, but there is no way I am getting in that water :)

They died out many years ago when the factory shut down for a few days in winter. But the legend lives on. The 12 cm ones are in fact young grey mullet ("harders" in Dutch language), which local fishermen confused with guppy's, even many years after there were no guppy's present at all! Already some 15 years ago I could't find any guppy's in this location despite several visits and some serious fishing. But access is not very easy and fishing with a dipnet is hard on the steep stone shores ("basaltblokken"). On the other hand, guppies are not the most difficult fish to net (as it turns out: young grey mullet can be very difficult!)

I am interested to hear ofany recent observations of tropical fish in such places, anywhere in Europe! (guppy's - normal sized and rather skinny, are reported from Germany and Hungary).

Another question, does anyone have a .pdf of the Italian article? I wrote to the authors to ask them directly, but never got a reply.

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Re: Invasive cichlids in Tuscany, Italy

Post by a.d.wood » Thu Oct 28, 2010 12:49 pm

illustrator wrote:..............

Another question, does anyone have a .pdf of the Italian article? I wrote to the authors to ask them directly, but never got a reply.
Follow the link given in the first post, click on 'download pdf' underneath the article title and off you go.

Andrew

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Bojan Dolenc
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Re: Invasive cichlids in Tuscany, Italy

Post by Bojan Dolenc » Thu Oct 28, 2010 2:46 pm

Thank You, a.d.wood. So simple as that :lol:

http://www.springerlink.com/content/d3k ... lltext.pdf
Change in habit, producing change of function, is the main cause of the production of change in living structure. F. Wood Jones (1953) Trends of life

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Re: Invasive cichlids in Tuscany, Italy

Post by newworldsss » Sat Apr 26, 2014 3:35 pm

Dan Woodland wrote:
SergeS wrote:So true. In Holland, there is apparently a population of Poecilia reticulata living in the stream where the cooling water exhaust of a large steelfactory is. They grow over 12 cm (4,5"!) in size and manage to survive through the - sometimes pretty cold - Dutch winters as the water is never too cold. I suppose they could even survive a season if they venture out too further, but during winter, any population that is too far away from their warm 'nest' will probably die so they are contained. I always wanted to see them myself, just out of curiosity, but there is no way I am getting in that water :)
This same situation occurred in Texas some years ago where bait shops sold Mbuna as bait fish and as fisherman do, they tossed the "leftover" bait into the river below a power plant. Last I knew there is still a thriving population of African Cichlids.


Mbuna as bait? Why?

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