zondag 18 november 2012

2012-11-18 08:32 Catfish and mini mud geisser

Weather : Overcast / NW wind 3 bft / Rain 0.0 mm / 1014.9 hpa
Divers : Remko, Stans, Axel
Goal : Visibility, Catfish
Max depth : 20.0 mtrs
Duration : 64 minutes
Air temp : 6.0 celsius
Water temp : 9,6 celsius minimum
Fish: > 5-10 eals resting at bottom. 1 catfish, some shrimp at depth
Visibility : 6,5 meters at 3 meter depth 
               7 meter at 6 meter depth and approx 3 mtr at 19 mtr depth.

Remarks: > 10 divers in water. No thermocline. From 0-20 mtr. 
After about 27 minutes we finally found what we came to see. First I found a piece of eal of about 3-4 cm thick. I know that Catfish also eat eal, but I never expected the Catfish to actually bite off chunks. 
Within a radius of about 3 meters I spotted the tail and when I approached it, it turned around and swam underneath me. We followed it for about 40 seconds and left it alone again when it turned around.
When it swam clouds of mud washed off it's skin so by the looks of it it too embedds itself in the bottom sediment.
Futher at 15 meter depth there were more clouds of dust. We came across a tiny sediment geisser from the bottom. My guess an eal embedded itself in the sediment, but I'm not sure.

Photo and video footage of the catfish and sediment geisser can be seen on this page where you can see two movies.

Please treat this beautifull Catfish with respect !!!


woensdag 14 november 2012

2012-11-13 19:46 Going deep!

Weather : Overcast / S wind 3 bft / Rain 0. mm / 1028.4 hpa
Divers : Remko, Kacper, Axel
Goal : Search Catfish
Max depth : 20.1 mtrs
Duration : 55 minutes
Air temp : 9.0 celsius
Water temp : 10,4 celsius minimum
Fish: > 5 big perch at about 13-15 mtr depth. 5-10 eals resting at bottom. > 10 Ruffe big and small. Loads of free swimming and hunting shrimp.
Visibility : 7 meters at 3 meter depth and approx 2 mtr at 19 mtr depth
Remarks: 3 divers in water. We went via the NW pontoon searching depth and stayed about 10 min at 19 meters. from about 17 mtr depth and down there is some airborn sediment but is coagulating into mucous like threads. I've seen that before.
No significant thermocline. From 0-9 mtr 11,2 celsius and 9-20 mtr depth 10,8 celsius.

zondag 11 november 2012

2012-11-11 09:52 The great visibility test

Weather : Clouds with sunshine / SW wind 4 bft / Rain 0. mm / 1011.6 hpa
Divers : Remko, John, Stans, Thijs, Jurre, Koos, Jan, Kacper, Axel
Goal : The Great visibility check
Max depth : 13.4 mtrs
Duration : 63 minutes
Air temp : 11.2 celsius
Water temp : 10,8 celsius minimum
Fish: > only a few young perch between the reedside
Visibility : 7 meters at 3 meter depth 
Remarks: > 15 divers in water.
Today I had asked 7 divers to do a visibility check using the same spool and visibility plate.On this plate you can see both Baseline and Secchi (two white squares) as shown in picture below.
I've used black and white insulation tape because it isn't glossy as laminated ones.
Every diver had to measure 3 times doing:
1-> Baseline meter two outer lines disappear and middle one still visible using lamp (Prescribed method)
2-> Baseline meter three lines disappear using lamp (Alternative method)
3-> Secchi 2 white blocks disappear wihtout using lamp

Of the 7 people the results were pretty constant. I also had asked them to determine which distance was the most realistic in their view.
In general 
1-> at 6,5 -7 meters the divers were still visible (This was considered the most realistic value)
2-> at 8-9 meters the divers began to fade and were not that recognizable anymore
3 -> at 10-11 only the white cylinders were seen but divers were not visible anymore.
On the righthand side you can see the measurements of each diver with the average values.
The lamps did have any effect with the sun shining, although it might give that little extra when it is clouded.

I've done quite a few tests, but never with a group of people this large. I will rest my case and never use anything else again :). I've also corrected the results in my logs.
It is unanimous... Baseline meter gives the best results!

vrijdag 9 november 2012

2012-11-08 19:34 Big shrimp / Temp drops rapidly.

Weather : overcast / W wind 3 bft / Rain 0. mm / 1016.3 hpa
Divers : Remko, John, Axel
Goal : Check SETL plates. Viz check
Max depth : 12.9 mtrs
Duration : 55 minutes
Air temp : 10.4 celsius
Water temp : 11,2 celsius minimum
Fish: > 1 juvenile Zander at about 12 mtrs. 1 young pike (30-40 cm) Furthermore we've seen Perch and Ruffes. just one big 3 cm long blue shrimp called Atheaphyra desmarestii. I've never seen this one here before though.
Plants : Elodea still stable from 1-5 mtr depth. 
Visibility :  7 mtr at 3 meter depth 
8 mtr at 6 meter depth. Remarks: 3 divers, No thermocline. Milky like water. 
SETL H135 (white tiewrap) : stable. algea threads gone.
SETL H136 (black tiewrap) : Totally clean.