What are the worst invasive fish species? In this video I will be trying to that question and many others you may have about invasive fish species. An invasive species is any plant or animal that has be introduced into an ecosystem where it doesn't belong, normally having negative impacts on native animal and plant species. Invasive fish don't only endanger native fish species but they can also cause millions of dollars worth of damage. Todays video is a little different as I will be going through 4 problem invasive fish species and 1 invasive crustacean.

Attributions

Signal crayfish images:
Andrew Reding
https://www.flickr.com/photos/seaotter/
J. Maughn
https://www.flickr.com/photos/jmaughn/
Astacoides
https://commons.wikimedia.org/w/index...
Creative Commons AttributionShare Alike 3.0 Unported
Don Loarie
https://www.flickr.com/photos/loarie/
David Perez
https://commons.wikimedia.org/wiki/Us...
Creative Commons Attribution 3.0 Unported

Signal Crayfish Footage:
Jarek Andrzejewski
   / @wodnikjarek  
razorista
   / @razorista  

White clawed crayfish footage:
jmkennedyie
   / @jmkennedyie  

Ruffe images:
Christa Rohrbach
https://www.flickr.com/photos/megaptera/
Tiit Hunt
https://commons.wikimedia.org/wiki/Us...
Creative Commons AttributionShare Alike 3.0 Unported
Gilles San Martin
https://www.flickr.com/photos/sanmartin/
Rawpixel Ltd
https://www.flickr.com/photos/vintage...

Black bullhead images:
NYS DEC
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Biodiversity Heritage Library
https://www.flickr.com/photos/biodivl...
Viv Lynch
https://www.flickr.com/photos/eskimo_jo/
Jeffdelonge
https://commons.wikimedia.org/wiki/Us...
Creative Commons AttributionShare Alike 3.0 Unported
Fishes of Georgia Photo Gallery
https://www.flickr.com/photos/georgia...

Black Bullhead Footage:
Benjamin Townsend
   / @mrbenjamintownsend  

Goldfish images:
Ryutaro Koma
https://www.flickr.com/photos/clryu/
nymawayca
https://www.flickr.com/photos/1546073...
veesees
https://www.flickr.com/photos/veesees/
Dennis Wong
https://www.flickr.com/photos/dennisw...
geraf
https://www.flickr.com/photos/geraf/
NYS DEC
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Cobia images:
NOAA Photo Library
https://www.flickr.com/photos/noaapho...
WIDTTF
https://www.flickr.com/photos/widttf/
Smithsonian Environmental Research Center
https://www.flickr.com/photos/serc_bi...

Cobia footage:
yuckysalad
   / @yuckysalad  
MarkPrimo
   / @markprimo  

Trout eggs image:
USFWS MountainPrairie
https://www.flickr.com/photos/usfwsmt...

Yellow perch footage:
Lurenet
   / @lurenetfishing  

Pike and walleye Images:
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lake trout image:
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Brown trout image:
NOAA Great Lakes Environmental Research Laboratory
https://www.flickr.com/photos/noaa_gl...

Red breast sunfish image:
NYS DEC
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Remora image:
Albert kok
https://commons.wikimedia.org/wiki/Us...
Creative Commons AttributionShare Alike 4.0 International

Shortfin Mako Shark footage:
Gonzalo Mucientes
   / @gonzalomucientes  

I have adapted and edited some of these original images.
Creative commons licences: https://creativecommons.org/licenses/

Our first problem invasive fish species is the goldfish. People have been keeping goldfish for thousands of years and since then we have moulded goldfish into many different colours and shapes. The goldfish is a relative of the carps and when released into a river or lake, it can soon take over the ecosystem.

Our next invasive fish species is the Eurasian Ruffe. This small member of the perch family is a small macropredator. The ruffe may not seem like a problem invasive species but it has proven to be so in the great lakes of America. As the ruffe competes with native species and also eats the eggs of other fish.

Our next Invasive species is the signal crayfish. The signal crayfish is a north American crustacean but can now be found over large parts of Europe and japan. If you have seen any videos on my channel before then you would have seen this species as it is in my intro.

Our Forth invasive fish species is the cobia. The cobia is a large ocean fish and is very popular with fishermen as they both taste very nice and put up a good fight. A small number of these fish escaped from a fish farm and are now spreading into the pacific.

Our last invasive fish species is the black bullhead. This medium sized catfish belongs in the waters of north America but is now a problem invasive species across Europe.