Alien species invade SA

[robfisher]

Alien species invade SA waters

<!-- m --><a class="postlink" href="http://www.iol.co.za/index.php?set_id=1&click_id=31&art_id=vn20080713120946160C613767">http://www.iol.co.za/index.php?set_id=1 ... 160C613767</a><!-- m -->

Alien invertebrates are invading South African rivers, competing with endemic species, and if their spread is not controlled, it could damage the habitat.

Prof. Chris Appleton, of the School of Biological & Conservation Sciences at the University of KwaZulu-Natal's Westville campus, said the first record of freshwater jellyfish (Craspedacusta sowerbyi) in the Midlands had been in Midmar dam in 1978. In 1989 it was discovered in Albert Falls dam and has spread to several Midlands rivers.

Explaining how these jellyfish were transported, Appleton said in their polyp stage they often got stuck in nets, or boat trailers.

"However, the real villains of the piece are the aquariums," said Appleton.

Scientists have found the polyp is able to survive the most unfavourable environments to flourish in a good year and believe they were part of a wave of post-war introductions of freshwater organisms to South Africa. "They were possibly introduced along with sport fish and aquatic plants destined for ornamental ponds or aquaria," he explained.

Other places where these jellyfish have made inroads, he said, were the Berg River in the Cape (where it was first found in 1958) and some rivers in the Johannesburg area.

According to Appleton, the major aliens are freshwater snails, which have thrived around the major ports from Cape Town to Durban and have also invaded some of the inland cities.

Two of the longest-established such species have expanded their range to include much of South Africa. Their ecological impact is that as microphagous feeders (grazers) they share their food resources with indigenous snails and some insects - which are being deprived of resources as the aliens proliferate.

Appleton will be speaking on this topic tomorrow at the J.S. Steel Auditorium Natural Science Museum at the City Hall, Smith Street entrance at 11am.

[Bergie]

Interesting article rob....geez you must have been k@k bored in kimberly!!!... :blue-badgrin: :blue-badgrin: :blue-badgrin:
--------------------------------------------------------------
fiss,fiss and fiss often!!
Cheers.

[Riem]

Geez uncle, I thought this was a fishing site? :blue-biggrin:

I see we are now talking about an Alien Invation....what's next.... a trip to Mars and a forum on UFO's? :blue-badgrin:

On a more serious note, I have seen fresh water jellyfish in the Upper Zambezi (and have pictures to prove it)! Thought they were indigenous? :blue-doubt:

[robfisher]

Well hello Ruffy... you have been quiet of late? You been away or just working hard?

I can’t say I have ever seen Jelly Fish in our local waters... amazing that they can hitch a ride on a sea boat and then propagate in fresh water...

[Riem]

Uncle,

Been on holiday for 2 weeks. Got back to work and it was really hectic :blue-evil: need another 2 weeks to recover! :blue-badgrin:

The dust seems to have settled and I now have time for my favorite past time... :blue-biggrin:

[robfisher]

The dust seems to have settled and I now have time for my favorite past time... :blue-biggrin:

Well in that case a very warm welcome back... I know what a holiday can do to your BFSA’ing because I just did 5 days of holiday! My dust still hasn't quite settled yet! :blue-shock:

[Ninja]

Geez Rob you of all people posting a topic with a heading longer than one line .... :blue-evil:

[Smeegle]

Does anyone know where I can find spinnerbaits in Craspedacusta sowerbyi, size 4/0 hook with carolina blades? Apparently the bass love 'em!

[robfisher]

Geez Rob you of all people posting a topic with a heading longer than one line .... :blue-evil:

It’s fits on one line on my screen so my OCD is in order! If it didn’t fit I would have had to edit it! :blue-shock:

[robfisher]

Does anyone know where I can find spinnerbaits in Craspedacusta sowerbyi, size 4/0 hook with carolina blades? Apparently the bass love 'em!

Ok good one Mr Mushroom… you had me going there… I even got all helpful and started googling for the colour! That’s a fine! :blue-razz: :blue-lol: :blue-biggrin: