Is this normal or is there something out of whack?

[drsteve 6]

Three weeks ago, I was on a 2 day trip to the Channel Islands. One the backside of Santa Cruz, we ran into what I call a brittle star desert. The sea floor was carpeted with a thick layer of brittle stars as far as I could swim. They were choking everything in their path. I have seen similar infestations before, but never this big. I wonder how common this is or if it signifies that something is out of whack. What eats brittle stars anyways?

 

These images are not the greatest, but they show what I am talking about.

 

Edited June 26, 2007 by drsteve

[Cerianthus 55]

I would say it is more common on soft bottoms. There are parts of the North sea that look just like this.

 

In our diving water the Oosterschelde, you can see these carpets as well (also in between rocks). They are now back after being not there for some years (climate, winters, I dont know).

 

Gerard

Edited June 26, 2007 by Cerianthus

[uw_nikon 0]

I would guess it's fairly common. Some of the sandy areas around Santa Barbara Island look exactly the same as your picture (if food's available, brittlestars will be there). But, most dive boats don't dive those areas.

 

Take Care,

ChrisS

[IMSushi 0]

You know Steve, there are spots on the back side of Anacapa Isl. that look just like that too. It seems, to me, that this is the result after an infeststion of urchins devours the kelp. The urchins finally leave and the onslaught of brittle stars soon follows. I kind of assume this because the stars are often found with thick purple urchins then on the extreme only stars?

[drsteve 6]

I don't think I was clear in my original question. It is certainly common. I have seen it many times, but is it normal? A similar question could be asked about red tides or Domoic acid outbreaks. They are common, and becoming increasingly more so, but they have been linked to various forms of environmental degradation. Perhaps a better question would be if there were as common a hundred years ago, when the fisheries were in better shape, as they are today.