Diseased urchins in so Cal?

[drbill]

I've been noticing an unusual number of urchin tests in Catalina's Dive Park lately. At first I assumed it was increased predation, but on inspection few of the urchins have any indication of direct predation. Then I noticed a number of tests with discolored areas. At first I thought it was due to lobsters gnawing on the tests. Finally I noticed areas of spine loss in patches on live urchins. Other local divers have commented on seeing the same in other locations on the leeward side between Long Point and the East End. This is the warmest stretch of coast on the island.

I know urchins and other echinoderms are affected by infections periodically, especially during warm water episodes. Has anyone else noticed this along the mainland SoCal coast?

Dr. Bill

 

[scottfiji]

Hey Bill,

It's good to know there are people keeping an eye on the local marine life.

It might help if you said "dead sea urchin shells" or "urchin skeleton" instead of "urchin test", since urchin test isn't exactly an everyday term on the mainland here.

I haven't noticed anything out of the ordinary here, the urchins seem pretty healthy, except for the ones that I split in half with my knife.

But now I'll keep my eyes peeled. It will give me something new to be on the lookout for in the water.

Scott

 

[archman]

Bill, is it species-specific, or a generalized trend? You guys have what, a type of Strongylocentrotus and something else mostly?

 

[sb_diver]

I see 3 types of urchins here in CA: Purples (Strongylocentrotus purpuratus), Reds (Strogylocentrotus franciscanus) and whites (Lytechinus anamesu)

http://biology.fullerton.edu/courses/biol_317/web/Murray/Fall97/sea_urchin.html

 

[JDog]

The LA area still has way too many, some places look like purple shag carpet. We were off of Topaz St. (We ran into Scottfiji and his fiancee here earlier this year).

 

[scottfiji]

Hey JDog, how's it going? Hope to see you at the next wrinkles.

Bill, I've seen more urchin endoskeletons (tests) lately..now that I'm looking... but the living still outnumber the dead...

sb_diver - don't forget about Dendraster excentricus... the Sand Dollar, a type of irregular urchin.

 

[OCdiving Deb]

I know urchins and other echinoderms are affected by infections periodically, especially during warm water episodes. Has anyone else noticed this along the mainland SoCal coast?

Dr. Bill

Dr. Bill, do you have any still photos you can post that will give us an idea of what you have observed?

I looked for the diseased reds while at Avalon over the weekend and did not see any. I'll keep my eyes open!

Deb

 

[Nay]

I've noticed what seemed like a lot to me, but I've only been diving since March so it's hard for me to say. I did see a boatload when I was in La Bufadora in March, but even then, there were more alive than dead.

Archman, we also have the Crowned Sea Urchin (Centrostephanus coronatus) which from what I can tell is kind of hard to distinguish underwater from the Red urchin without really trying to. I know you're not as up on your CA species as east coast, thought you might like this web site, which I use quite a bit for species ID. http://www.divebums.com/FishID/index.html

I'd be interested to see if anything if in fact we're facing some sort of infection and how that will affect the kelp forrests. Especially with the predicted El Nino this winter.

 

[drbill]

Nay- actually Centrostephanus (crowned or black urchin) is easy to distinguish from the red urchin (S. franciscanus). First, the spines are much longer relative to the size of the body (test) in Centrostephanus. Second, if you run your finger DOWN the spines, the reds are smooth while the blacks have rings or ridges n the spines.

I will try to remember to add an image when I get a chance... I'm just "home" for 36 hours between talks on the mainland.

Dr. Bill

 

[SoCalAngel]

It might help if you said "dead sea urchin shells" or "urchin skeleton" instead of "urchin test", since urchin test isn't exactly an everyday term on the mainland here.

Are you implying that divers are stupid and don't know scientific terms.... :11ztongue
I am joking, a bit. I know what a test is. If Dr. Bill doesn't use correct terminolgy, how will the rest of us ever learn?

Dr. Bill, I have noticed this over the last several months, actually. I remember noticing it at Montage a few months back, at Shaws about 2 months ago, at San Clemente last month, too. I noticed the phenomena, but hadn't really thought much of it.