dinsdag 7 augustus 2012

2012-08-07 14:38 hbos Algeabloom starting?

Weather : Clouds / W wind 3 bft / Rain  ?.? mm / 1018.0 hpa
Divers : Erna, Axel
Goal : Visibility, Watersamples.
Max depth : 9.7 mtrs
Duration : 56 minutes
Air temp :  17.0 celsius
Water temp : 20.8 celsius minimum
Fish: > young fish (perch and next to Paviljoen at 4,5 mtr young Ruffe, 1 eal, 1 Carp, 1 dark striped pike.
Plants : It looks as if Potamogetons are less abundant near entry, but Elodea (Waterpest) is growing. The sediment colours the Elodea in a light brownish green. As you go deeper the Elodea is dark and fresh green
Visibility  : 3,5 mtr at 3 mtr depth, 4 mtr at 6 mtr depth
Yellow viz: 3,5 mtr at 3 mtr depth, 3,5  mtr at 6 mtr depth
Remarks:  2 divers. The top layer of the water seems to become greenish of colour and starts to thicken. Little mucouslike threads are sinking. 
Little Perch approx 5 cm are abundant and are swimming in schools. 
A school of young Ruffe are in en very clear patch next to the Paviljoen at 4-5 mtr depth. A dark striped pike was probably hunting the young Ruffe as we blew it's cover. 
We cleaned up a plastic bag filled with rubble and removed various cans and plastic waste.
It strikes me how fast (large) Mussels are settling on plastic and tin cans.
There is probably a need for more hard substrate for the mussels to grow on in a depthrange from 2-6 mtrs.
I'm thinking about placing plates at various depths and see how fast mussels settle on it.
These mussels filter the water.

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