vrijdag 29 maart 2013

2013-03-29 09:51 Goldfish / Visibility gets worse

  • Weather : Clouded / NNW wind 2 bft / Rain = 0 mm / 1010.0 hpa
  • Divers : Paul, Axel,
  • Goal :Visbility and check out SW pontoon
  • Max depth : 16.4 mtr
  • Duration : 60 minutes
  • Air temp : -1 celsius
  • Water temp : 3,8 celsius minimum
  • Fish:  1 Perch, 1 dead goldfish, Copepods in area C
  • Plants: Elodea more and bigger in Area C.
  • Dutchi visibility at 3 mtr depth 5,5 mtr.
  • Dutchi visibility at 6 mtr depth 5,5 mtr. 
  • Secchi visibility at 3 mtr depth 7,5 mtr.
  • Secchi visibility at 6 mtr depth 7,5 mtr.

Comment: Paul and I head out the the measurepile at 3 mtr. We noticed a brownish layer at the bottom and clayblocks. Visibility has decreased dramatically from 12 to 7,5 mtr in 10 days.
There is word that there was a trial run of the airpumps last week.
Also pieces of Cod lie at the bottom next to the restaurant.

After I did my usual visibility check and photo we went south.
Just above the bottom the visibility is better due to the mussels who filter the water. Above that layer of about a meter thick the visibility varies from estimated 7-10 mtr

After a while we altered the course more west until we reached the SW pontoon. The airhose is detached from the airplate and lies on the bottom. We followed the hose over the bottom going south. Beautiful clay blocks and a sloping bottom. This is my favorite spot. As we passed a dune I saw a tree trunk of about 30 cm thick and about a meter long stuck in the bottom. We headed North as the visibility was good in the SW area. Also much more copepods in the SW area then in the dive area.The further we approached the restaurant the worse the visibility got.  At 5 mtr an orange object caught my eye and it was a goldfish. It was damaged at the tail. Maybe by a Herron. 
Tree trunk

Under the restaurant there was floating sediment as they were cleaning the deck of the restaurant. I took a sample of the brownish gelatin to check later under de microscope. Clearly the persisting low temperatures is taking it's toll on fish. The temperature is 4 degrees lower than last year.
Dead goldfish
Brownish layer

Very good visibility

If you wonder what is in this brownish gelatin then take a look here. It would be nice if someon
could help me identify it all. Here is a movie of the very active organisms

Long string:
Fragilaria sp. Pennate Diatoms

Cone shaped diatom on the left:
Could be -> Surirella.

The diatom attached to the long string in middle:
Could be -> Cymbella.


Brown gelatine
Diatoms and

woensdag 27 maart 2013

2013-03-19 19:51 Little frog at 10 mtr, Brown-yellow growth.

Weather : Overcast / E wind 3 bft / Rain = 0 mm / 998.4 hpa
Divers : Remko, Robin, Axel,
Goal :Look around at NE bank
Max depth : 11.9 mtr
Duration : 45 minutes
Air temp : 3.0 celsius
Water temp : 3,8 celsius minimum
Fish:  1 Zander, many Ruffe, Copepods near drum at 4-6 mtr near two dead Coots.
Dutchi visibility 3 mtr depth x mtr
Dutchi visibility 6 mtr depth x mtr 
Secchi visibility 6 mtr depth x mtr
Plants: Elodea , individual small plants grow at banks and individual Potamogeton.
Area A/B

Comment: We headed out the North East bank. As I was checking out the bottom, a little frog caught my eye.
I was amazed to see this little creature at a depth of 10 mtr on a bed of zebramussels. It could be a brown or green frog, but that needs to be determined. As we continued and passed the anchorline of the NE pontoon. At about 4 mtr depth yellow algea can be found attached to twigs and small Elodea. Near the drum the amount of shrimp and copepods increased and not to far away Remko discovered two dead coots. One of them had swallowed a fishinghook and the other was entangled. They were victimized by lost bottomfishgear as I found the weight with the line attached to the Coots beak. Remko also found a lure in the form of a plastic little Pike with a protective sleeve over the hook. So apparently the fisherman did not want to catch anything
We find quite a lot lost fishinggear.

Small frog < 2 cm at 10 mtr depth.

Potamogeton ??

woensdag 20 maart 2013

2013-03-17 SETL sunday

Weather : Clouds with sun / SE wind 4 bft / Rain  2.8 mm / 995.5 hpa
Divers : Cees, Axel
Goal : Place SETL H124 and retreive H136 and H106 for photograph. Place all plates back
Max depth : 18.9
Duration : 50 minutes
Air temp : 5.5 celsius
Water temp : 3.8 celsius minimum
Fish: > 1 embedded eal, Perch, and shrimps on the bottom, some copepods in watercolumn.
Dutchi visibility 3 mtr depth 8,0 mtr
Dutchi visibility 6 mtr depth 8,0 mtr 
Secchi visibility 3 mtr depth 12,0 mtr
Secchi visibility 6 mtr depth 12,0 mtr
Plants: Elodea , individual small plants grow at banks. Elodea in unrooted (tumbleweed like) bushes remain constant being covered with a thin layer of sediment. 
Area A/D

Comment: First hangup new plate H124. Picking up H136 and H106 for photography.

H136 - start 27-09-12 -> Young mussels have grown bigger to 2,5 mm
H106 - start 15-12-12 -> Brown yellow gelatine like layer on the brick and thread. Very small mussle specks on the plate.
Full report will follow
My buddy Cees was testing his gear for a holliday in which he wanted to go deep. Along the dive we saw an embedded eal. at about 17 mtr depth. 

H136 with tiny mussels.

donderdag 14 maart 2013

Evenementen hbos Carpmaster viswedstrijd 5-6-7 april

5-6-7 APRIL Carpmaster viswedstrijd.

Vrijdag 5 april 15.00 uur tot zondag 7 april 12.00 uur
Op deze datums wordt er een Carpmaster viswedstrijd gehouden in de Haarlemmermeerse bosplas. Het wordt afgeraden om te duiken. Mocht je perse toch willen duiken wijk dan eventueel uit naar Toolenburgplas Er zijn totaal 17 viskoppels die de oevers compleet zullen bezetten.

zondag 10 maart 2013

Meerval houdt niet van felle lampen! advies ->

Hallo allemaal,

De meerval houdt niet van felle lampen. Advies voor duiken overdag,
Zodra je een meerval ziet en wil benaderen, scherm dan je lamp af met je hand.
Er is genoeg omgevingslicht om de meerval goed te zien.
Hierdoor verstoor je de meerval het minst en kun je hem/haar dichter benaderen.

In slecht licht omstandigheden moet je je lamp wel aan hebben, maar indien mogelijk kun je overwegen je lamp te wat te dimmen en of niet op de kop te schijnen.
Doe je dat wel dan zal ie mogelijk snel weg zwemmen.

2013-03-10 09:59 Very clear water

Weather : Overcast / NNE wind 5 bft / Rain > 0 mm / 1002.0 hpa
Divers : Paul, Axel,
Goal : Check out deep section again / Visibility reading / SETL check
Max depth : 18.8 mtr
Duration : 57 minutes
Air temp : 0.6 celsius
Water temp : 3,4 celsius minimum
Fish: >2 eal, 2 perch, 1 Catfish
Dutchi visibility 3 mtr depth 8,0 mtr
Dutchi visibility 6 mtr depth 8,0 mtr 
Secchi visibility 6 mtr depth 12,0 mtr
Plants: Elodea , individual small plants grow at banks. Elodea in unrooted (tumbleweed like) bushes remain constant being covered with a thin layer of sediment. 
Area A/D

Comment: Going straight ahead where we could oversee the banks and clay reefs with ease. In that respect the Secchi visibility comes closer to my feeling of distance than Dutchi in this case. First we spotted a big eal at about 13 mtr dept after 2 minutes in the dive. At about 8 minutes we passed the reef at 15 mtr depth. There I saw an eal tail. Normally the head sticks out on the other end, but in this case the head was no where to be found.

As we came in the deep section there were some prints in the bottom where big fish had rested. It is awesome to see how many big blocks are scattered on the bottom. Besides a few dust clouds it was nice and clear. We turned right where actually the bottom ascended pretty steep going up to 15 mtr and less coming from 18 mtrs. An anchorchain with an airtube attached and some flexible pipes stuck in the bottom. Along a ridge we swam back into the deeper bit. There I spotted a smaller catfish of about 1 mtr long. We covered our lamps to avoid scaring the catfish. Dark olivegreen with white edges on it's tailfin and pectoral fins. At that point Remko joined us after he had problems with his divegear, but had managed to fix it afterall. We ascended left from the Paviljoen which I had in mind. We swam to the outer measurepile and did a visibility reading on Dutchi and Secchi.
After that I checked out the SETL plates which will be taken to the surface next week. 3 months pass very quickly.
At the measure pile a dark brown layer of (I believe) diatoms are settling over the bigger mussels. There are a few big sized musselcolonies on the pile where the smaller ones had dislodged. At this tempature though younger mussels of about 2-3 mm are starting to grow near and on the rope.

H136 is home to many young shrimp and young (white quaga?) mussels are growing steadily.
H106 the common fishleach is gone again. At edges the same brown layer of diatoms are present.
At the line and knot of the brick a snotty or bryozoanlike growth is attached. funny is that H136 doesn't have it.
So it is apparant that within a meter distance of each other  growth is so very different.
Unfortunately I do not have photos.


woensdag 6 maart 2013

2013-03-05 20:31 hbos copepod soup

Weather : Clear / SSE wind 3 bft / Rain > 0 mm / 1007.9 hpa
Divers : John, Kacper, Axel,
Goal : Visibility reading check difference between plate and printed/laminated version, looking around at depth
Max depth : 19.4 mtr
Duration : 55 minutes
Air temp : 12.0 celsius
Water temp : 3,0 celsius minimum
Fish: > 1 Zander at 7 mtr, Copepods soup in dive area and under Paviljoen, extremely active (hunting) shrimp.< 10 bigger Ruffe spread between 12 and 17 mtr depth. < 10 smaller Perch. 
Baseline visibility:  7,5 mtr (trespa plate)
Baseline visibility:  6,5 mtr (printed version)
Secchi visibility:  10.5 mtr
Plants: Elodea , individual small plants grow at banks. Elodea in unrooted (tumbleweed like) bushes remain constant being covered with a thin layer of sediment.

Comment:In the dive area left from the Paviljoen a soup of copepods is very active, but funny enough only in the dusty area. As soon as you come into clearer areas the copepods are less concentrated. So divers that agitate sediment, attracts copepods and shrimp that feed on these copepods. With regardds to visibility reading, Kacper was curious what the difference between a printed version and the trespa plate was. Printed version gives about 1 meter less, because the lines are not as white as the trespa version.

After visibility we went for the deep. Again in the dusty areas more copepods are active. Loads of shrimp under and near blocks of clay. We went east from the middle and had to swim quite a bit. 
The slopes of the NW bank are sandy and very bare apart from a small Elodea here and there. 
Near the drum a cloud of very active copepods again.
Very nice dive, with warm hands after 7 years of coldwater diving thanks to GNT gloves. 
Area A,D,B

maandag 4 maart 2013

Steeds meer duikers loggen hun duik!!

Hallo allemaal,

Het is ontzettend leuk dat steeds meer mensen hun duik loggen op deze website.
Zo krijgen we steeds meer informatie binnen die wordt gebruikt om nog een beter beeld te vormen van de plas. 
Als je begint met loggen dan zul je in de loop der tijd je duik anders gaan beleven, omdat je anders en bewuster gaat kijken. Om het simpel te houden kun je de
focus leggen op het verloop van 1 diersoort of plantensoort. Niks moet alles mag natuurlijk.
Om een paar algemene voorbeelden te noemen;

-> Hoeveel grote vis heb ik gezien?
-> Welke vissen heb ik gezien (ook dode vissen bijvoorbeeld.)
-> Heb je de zoetwaterkwallen gespot? 
-> Waar ligt de grens van mossels?  Bij Paviljoen zitten ze nu 8 meter en dieper.
-> Was het mistig op sommige plekken en hoe diep?
-> Zijn er thermoclines zo ja hoe diep en misschien het temperatuurverschil?
-> Vissen kunnen bijvoorbeeld ineens (on)dieper gaan zitten dan normaal.
(05-2012 zaten in de algenplukken tot 5 meter diepte heel veel palingen die nadat de algen verdwenen ook weer naar diepere wateren vertrokken).
-> Zie je roeipootkreeftjes in de waterkolom (schijn met je lamp voor je en kijk naar schichtige bewegingen.
Leuke is dat in het voorjaar een explosie van roeipoot kreeftjes en/of aasgarnaaltjes te verwachten is, na het moment dat baarseitjes zijn uitgekomen. Baarsjes voeden zich daar weer mee.
-> Roeipoot kreeftjes zijn meestal ook weer te vinden in wolken met opgegooid stof.
-> Wanneer spot je de eerste baarseitjes en hoe diep liggen ze bij welke temperatuur?
-> Wanneer beginnen planten te groeien / af te sterven?
Legio voorbeelden die je duik leuker kunnen maken en ons weer kunnen helpen.
Alvast hartelijk dank voor het invullen van de gegevens