OK to cut up black sea urchins?

[wetrat]

Uuuuuh, no thanks! No need to see a great white here!

 

[wetrat]

Just take some chum down with you, if you lucky you may even attrack a great white.........oooh, party time!!!!!!!!!

On the other hand..... I was thinking maybe diving at Guadalupe Island wearing a "steak suit."

 

[Rick Inman]

As far as killing them, well it really depends on where you are. Don't do it in a Marine Reserve, but kill as many of them as you can anywhere else These things destroy kelp beds.

Anybody remember back in the 70's when we were encouraged to bring hammers to PV and wipe out as many sea urchins as we could?

Times have changed...

 

[drbill]

Hmmmm... we were at the Coronados (Lobster Shack) in about 40 fsw. These were very spikey, 3-4 inch diameter with about one inch spikes. Color may not be black because I didn't shine a light on them. They were in every crack of the rocky reef.

wetrat

Urchins with a high test diameter to spine length ratio are most likely not black (or Coronado) urchins. These urchins are subtropical and characteristized by relatively small tests and long spines that are rough if you run your finger down them. Urchins with larger tests and smaller spines as described here may be the red urchin (which looks black at depth without a light).

 

[drbill]

Anybody remember back in the 70's when we were encouraged to bring hammers to PV and wipe out as many sea urchins as we could?

Times have changed...

While true on the mainland in the days when sewage wastes offered the urchins a secondary food source after they'd devastated the kelp beds, this has not been true on the islands (at least the southern ones) unless they've been fished out of urchin predators like sheephead. It really irritates me when I see divers in our dive park killing any urchin to feed the fish. The high density of sheephead (and kelp bass and garibaldi) keeps a good control on the urchin populations here (except at night when the sheephead sleep and the black urchins are out and about).

In areas of the mainland and northern islands where sheephead have been fished out, urchin control might be a more reasonable thing.

 

[wetrat]

The high density of sheephead (and kelp bass and garibaldi) keeps a good control on the urchin populations here (except at night when the sheephead sleep and the black urchins are out and about).

Thanks Bill,

This is really good information. I will definitely pass it on because as divers I believe education is really our greatest tool to keep ocean ecosystems healthy. Also, I did a google image search and it looks like we cut up purple urchins. The proportions of the urchins in the pictures were identical to the ones I thought were black at the Coronado islands.

wetrat

 

[CaptAdam]

There stupid sea urchins.......

 

[saf_25]

I had also heard, and correct me if I'm wrong (Dr Bill, I'm sure you'd know this), that the urchins emit some sort of signal when they get harmed (ie - cut up) that tells the other urchins that danger is present. This signal causes them to release their gametes (reproductive "pieces") into the water, so injuring them actually results in greater populations. Is that just hogwash, or is there some truth to that?

 

[Kayak Diver]

There are so many urchins down there...don't know how a few Socal divers are going to make a huge dent in the population by having a little fish feeding fun. You guys must eat tofu and wear Burkenstocks. All the nice shiny plastic, nylon, and metal you take scuba diving does more harm to the environment than killing a couple of urchins. Not to mention all the fossil fuels you burned getting there...

 

[drbill]

I had also heard, and correct me if I'm wrong (Dr Bill, I'm sure you'd know this), that the urchins emit some sort of signal when they get harmed (ie - cut up) that tells the other urchins that danger is present. This signal causes them to release their gametes (reproductive "pieces") into the water, so injuring them actually results in greater populations. Is that just hogwash, or is there some truth to that?

Possible in some species, but I've personally never seen a gamete release in response to injuries to blue, red or black urchins.

Dr. Bill