fredag 21. juni 2013

Not a WoGE, nor "Overburden"

This one won't be used for a WoGE, nor anything else. I haven't a clue how these structures formed, nor whether they are natural or man-made.

But in case anyone wants to search for it, I am not showing the coordinates. :D

It's in an artificial lake, somewhere warm and wet.

4 kommentarer:

  1. -10.95°, 27.04° Lake Tshangalele, what a wonderful picture with such interesting structures!
    But what ist it. I would say we do see a path of a fishing or hunting boat in the plants growing or swiming in/on the lake. I think we can see something like a "main street" with many little branches. The spirals could be the traces of some sort of hunting strategy.

  2. You found it Felix. :)

    I stumbled across it when I was looking for your floating islands ( ), and decided it was too weird not to post it.

    I have no idea what it is, nor why it seems to be limited to Lake Tshangalele. Whether it is caused by human activity, animal feeding strategy, or other kind of biology, I find it strange that it is so abundant in one specific place and then nowhere else.

    In some places there seem to be buildings along a "main road". Maybe we should ask the locals. :)

  3. I haven't found a local to ask, but maybe I have reasoned out what it is?

    Lake Tshangalele is very shallow, with a mean depth of 2.6m only. Yet it is one of the main sources for fresh fish at the markets in Lumumbashi, about 90km distant. The fish is called "Kapolowe", after the town nearest to where the spirals are most common. Hmmm...

    If the average depth is 2.6m I think we can safely assume thet the most reed-covered parts are even shallower. So how do you catch commercial quantities of smallish fish (greenhead tilapia, about 25cm) in water that barely comes up to the knees, and is covered with reeds too?

    Small boats ( are always useful, but nets are as good as useless among the reeds. Traps work better, but in conditions like this the fish have no incentive to move.

    So you make them move towards the trap by paddling in an ever tighter spiral, splashing as much as possible. Keep doing this, and you will "wear a groove" in teh reeds. Then when the water silts up or the reeds get too thick, you move the whole operation to the new edge of the reeds.

  4. Looks like a resonable explanation.