Purple Sea Urchins

[StefinSB]

Bill, did you guys get the sea star wasting disease down there? I know that when it hit up here the whole area started filling up with urchins. I never realized how much they were kept in check until that disease pretty much wiped out the sea star population ... which is fortunately beginning to make a comeback ...

... Bob (Grateful Diver)

We had the sea stars desease her in Central Cali and those urchins are everywhere.

 

[MaxBottomtime]

We had sea star wasting in SoCal and it is only now beginning to show signs of a comeback of sea stars. Sunflower stars are still non-existent. The only other predators here are sheephead and lobsters, both of which are heavily hunted. A great read is Bluewater Gold Rush/The Odyssey of a California Sea Urchin Diver.

 

[drbill]

Bill, did you guys get the sea star wasting disease down there? I know that when it hit up here the whole area started filling up with urchins. I never realized how much they were kept in check until that disease pretty much wiped out the sea star population ... which is fortunately beginning to make a comeback ...

... Bob (Grateful Diver)

Yes, we did, Bob. However in my waters sea stars aren't generally big predators on urchins. About 90 miles north ini the path of the colder California Current there are some though.

We also had mass die-,offs of urchins during El Nino and other warm water events. Only the southern black urchins (Centrostephanus) appeared unfazed by those events.

 

[drbill]

The only other predators here are sheephead and lobsters, both of which are heavily hunted. A great read is Bluewater Gold Rush/The Odyssey of a California Sea Urchin Diver.

Thanks, Phil, for adding lobbies to the predator mix. I've filmed feveral of them chowing down on urchins

 

[drbill]

We don’t have sheephead in Norcal north of the GG, so that was never the predator here. A long time ago it was the large northern otter that used to feed on urchins and abalone....

The main reason for the current problem is pollution, very simple...

The urchin problem is normally controlled by voracious giant stars up here. .

No question the ecological conditions there are much different from those in our warmer waters. Even down here pollution, was a major factor in the urchin problem, especially untreated sewage before the clean water legislation in the early 1970's, Otters were a major factor all along our coast and their decline removed removed one highly significant predator. Fortunately we had others here that stepped in to take their place as urchin munchers. Then humans intensified take of sheephead, lobster and others. Out here on Catalina we rarely see predation by sea stars. The species that do so are largely confined to the mainland and to cooler regions slightly north of here.

 

[Akimbo]

A great read is Bluewater Gold Rush/The Odyssey of a California Sea Urchin Diver.

FYI for all, @covediver did a nice review: Blue Water Gold Rush and The Last Pearling Lugger