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Knysna: INFO

Knysna, Tsitsikamma, Wilderness
Seahorse
Posts: 28
Joined: Thu Dec 29, 2005 11:54 am

Knysna: INFO

Unread postby Seahorse » Fri Dec 22, 2006 9:17 pm

We recently did a few dives in Knysna lagoon to have a look at the changes in bentic life after the august floods in the lagoon.
It was quite depressing to note that most of the marine species on the bottom had disappeared.
However , we have seen this phenomenon before, and the recovery was usually fairly rapid. This year things are taking a little longer to come back.
One very interesting appearance was a little scorpionfish, probably Pterois miles, that was found under the jetty at Thesen Island.The last time I saw a Scorpionfish on the South coast wasmore than twenty years ago in tsitsikamma.
The sea around here is also full of a very beautiful little purplish brown jellyfish this year. They also wash into the lagoon.
We will watch the bottom dwellers carefully and will report on any new arrivals.
Peet Joubert
Park Manager (Knysna)

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DuQues
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Location: Red sand, why do I keep thinking of red sand?

Unread postby DuQues » Wed Dec 27, 2006 12:10 pm

Was this due to the mud deposited, or the force of the water?
Arriving currently: The photos from our trip! Overhere! :yaya:

Feel free to use any of these additional letters to correct the spelling of words found in the above post: a-e-t-n-d-i-o-s-m-l-u-y-h-c

Seahorse
Posts: 28
Joined: Thu Dec 29, 2005 11:54 am

Flood damage Knysna Lagoon.

Unread postby Seahorse » Mon Jan 15, 2007 9:23 pm

There are several causes for the deaths after the floods.
One reason would be the suspended solids from the erosion during the storm.
Another possible cause could be changes in chemical composition of the water , but in all probability the most deaths were caused by prolonged immersion in fresh water.
Vast amounts of fresh water was trapped in the lagoon for days.
Marine animals can not tolerate fresh water for long. Most of the sessile animals were just subjected to fresh water for too long.

An interesting development at the moment, is the development of a layer of marine filamentous algae all over the bottom. It covers the layer of silt on the bottom as well as most of the remains of animals left behind.
We can already see some new colonizers developing in Featherbed bay. There are also lots of sponges starting to grow on any hard surface.
Peet Joubert

Park Manager (Knysna)


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