Tag Archives: Purple Sea Urchins

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Abalones are struggling. The voracious Purple Sea Urchins are eating the Abalones' food source, which is kelp. To survive, Abalones have moved closer to shore, which brings problems for them too. But the Urchins can't survive in the wave action, so the Abalones have a measure of safety there - unless big surf knocks them up on the beach. Marilyn Green recently photographed a group of them during a recent low tide.

 

We see signs of imbalance in the ocean. And we also see signs of balance returning, like seeing more Sea Stars. We will continue to watch and learn.

Thanks to Marilyn for allowing me to share her photo with you here.

Today is a rainbow day, and tomorrow brings a big storm for late in the day. As I type this, I can see a storm cloud on the ocean, dark with rain, and headed my way! Not a good time to take a walk.

 

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Here are two videos Jack Likins recently took while diving near Arch Rock Road in The Sea Ranch. He entitled one “the good” and the other “the bad.” Jack wrote, “The one clip shows some of the good, almost environmental normal, areas with healthy vegetation and sea life; and the other clip shows the same general area where the Sea Urchins are taking over.” Jack tells me that Sea Urchins have taken over the deeper waters, twenty feet and deeper. Here's a photo taken by Roger Rude of several healthy Abalones.

The Good, a healthy intertidal zone by Jack Likins

 

And here is the "bad," the ocean floor taken over by purple Sea Urchins.

Jack wrote further, “The remaining Abalone have moved into depths less than 20 feet where there is kelp [food] that the urchins haven't eaten.  I don't think the urchins like the shallower water because they can't hang onto the bottom in the rougher shallow and intertidal areas.  I'm not seeing much bull kelp but am seeing boa, giant and palm kelps, mostly in the shallower water.  I do see some short stalks of bull kelp underwater but it seems to me that the bull kelp is showing itself on the surface later and later each year, so we'll have to wait to see if it gets to the surface before the urchins eat it this year.”

There is some bull kelp to be seen off the north end of Gualala, but it is sparse. We hope the ocean can get back in balance. We know Sea Stars are recovering, so there's good news there.

Thanks to Jack for allowing me to share his videos with you here, and thanks to Roger for allowing me to share his photo with you here.

Sunny and warm at our place in Anchor Bay, though fog covers most of the ocean.

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After a hiatus of several years, Red Sea Urchins have once again been harvested and brought to the Point Arena Pier. Michael Alexander photographed the first ones destined for sushi chefs here and in Japan that feature uni, the gonads of Red Sea Urchins.

It's not easy to harvest them. A diver will work with a partner on a boat, and stay underwater for several hours at a time collecting them. It's hard work!

These are not to be confused with the Purple Sea Urchins that have proliferated in recent years due to the Sea Stars contracting a wasting disease - Sea Stars prey on Sea Urchins. The purples, unchecked, have eaten much of the kelp, causing some Abalones to starve. Here's what they look like, photographed by Jon Loveless.

Sea Stars have recovered this year and we hope balance will return to the inter-tidal zone.

Thanks to Michael and Jon for allowing me to share their photos with  you here. We are having another lovely, warm day on the Mendonoma coast.

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The Stornetta Public Lands bring us many wonders and here's another one - a Purple Sea Urchin "meadow." Peter Baye was exploring the tide pools of the Stornetta Lands at low tide recently when he photographed these underwater beauties.

These Sea Urchins have excavated pits in sedimentary rocks and live in a big community. They grow to about four inches across and can live up to 70 years. Their Latin name is a tongue twister - Strongylocentrotus purpuratus. They are found off the eastern edge of the Pacific Ocean, from Ensenada, Mexico to British Columbia, Canada.

Thanks to Peter for allowing me to share his photo with you here.