Robotic Urchin Harvester Project - Otter Force One

[Bigbella]

“Most urchins in a barren are sterile, but you do find some that are reproductive,” she says. “We want to be sure nobody is smashing urchins during the reproductive cycle.” Purple urchins usually spawn naturally in winter months.

There is a bit of difference between, say, the height of a given reproductive cycle and / or some complete cessation; and the woman in that article. Rogers-Bennett, was specifically interested in getting a particular "crop" of purple urchins to some arbitrary market size aesthetic, whose buyers are notoriously particular -- not that they were necessarily incapable of reproduction beforehand. Sure, there is the "primary" season in the Winter; but in Northern California, ripe animals can even be found through July and September.

Below are some visibly spawning urchins from a mid-June collection.

I have also failed to see any appreciable change to areas where culling -- legal or otherwise -- has been performed, whether through physical removal or slag hammers; and have seen plenty of young urchins, particularly off the Sonoma Coast, near Sea Ranch, whose sexual maturity commences when they reach only 25 mm.

We collect urchins almost year-long, for laboratory use -- and have rarely failed to get them to spawn, even in so-called off-months, when we would occasionally switch to sand dollars (another echinoderm order -- basically a dorsal-ventrally flattened urchin with highly-reduced spines).

Aside from chemical methods to induce spawning (injections of 0.55 M KCl, seawater, even air emboli), protocols for bioassay usage, have also encouraged, when all else fails, direct "injury to conspecfics" to induce spawning; that is to say, the use of a hammer . . .

 

[FlaminglotusSJ]

That device looks pretty cool, a little complex and techy but cool none the less.
I still think removal by hand is probably quicker and easier.

We are allowed to harvest 40 gallons of purple urchins per day in the purple urchin problem counties. There is no possession limit.

There are only two sites that are designated as culling zones, one is Caspar Cove in Mendocino County and the other is Tankers Reef in Monterey County.

I can remove 40 gallons of purple urchins in less than a few hours and I can do it a lot of times on one tank of air (three shallow dives). I have the biggest green game bag that Trident makes and I stuff it full three times which works out to be 40 gallons of whole urchins.
I use a 50# lift bag to suspend the collection bag once it begins to fill to make it easier to float around. I put just enough air in the lift bag to make the urchin bag neutral. I estimate that 40 gallons if urchins is somewhere between 800 and 1200 individual animals.
I use an old ab iron to knock a few stubborn urchins loose that have locked down on rocks. Most of them are easy enough to just handle carefully with kevlar gloves and get them into the game bag. It is very quick work to fill a bag (15 to 20 minutes, and that is a very large bag, much larger than the one shown on the urchin vacuum machine.
Most of my work is in 8-10’ of water right off the beach. I have been concentrating on Stillwater Cove in Sonoma County as my pet project area. All my efforts are concentrated there. I’m seeing a lot of small abalone coming back along the interface between the kelp weed line close to the beach and the barrens a little farther out. I work from this urchin free interface zone outward in an effort to increase the area out from the beach where the abalone can feed and be urchin free. My fear is that with the pending winter storm season looming that the abalone will be dislodged from the shallow beach zone by large swells and flung onto the beach during large winter storms, since that’s where all of them seem to be thriving.
It is critical that we do everything in our power to try and get this problem under control. Like the article says, healthy kelp is critical to a lot more than just abalone and fish, it affects CO2 levels in the atmophere also.
We need to clear urchins!!

I have plans to attend several DFW public meetings to try and introduce at least three new motions regarding purple urchins. One would be to remove or suspend the 40 gallon limit and change it to no limit take. The second would be to suspend the general wanton waste clause specific to purple urchins and have that in writing, and the third would be to suggest enacting a cash bounty for purple urchins based on poundage. The price paid would have to be determined and a collection and weigh station would have to be created.
Perhaps a good place to spend some of that state budget surplus?

I have been trying to get people involved in purple urchin removal for months even years. So far I’ve very little success. People seem to be more interested in their own pleasures and don’t want to be bothered by doing work dives. It’s a little frustrating to say the least. Trying to get divers together as a team to do this is like herding cats
I’m going to continue to try and recruit divers for this project. I’m going to talk to Seal’s Water Sports in Santa Rosa and see if they would be willing to put up a special purple urchin removal information page on their website with info about where-when-how and have sales on urchin removal gear like large green game bags, lift bags, bars, clips, etc.
I’m also going to continue to post here in an attempt to get people interested and fired up.

I sincerely hope many of you take this problem a little more seriously, this is an important and noble cause.
Please get involved.

Eric, thank you for sharing your effort and experiences! Any update on the present weight limit in CA, or regulation updates?

 

[Eric Sedletzky]

Eric, thank you for sharing your effort and experiences! Any update on the present weight limit in CA, or regulation updates?

There is no weight limit, only a volume limit of 40 gallons of whole purple urchins. The 40 gallon limit is a DFW rule, but all they say is 40 gallons of whole urchins meaning they don't want you smashing them down in the container because five gallons will turn into one gallon if you puree them. But we can pack them down by dropping the can down a few times and settling them allowing to top up the can several times. We use 20 gallon Brute trash cans.
However, I do keep track of weights since I'm curious of the poundage, plus the kelp restoration office at NOAA likes to know what we're doing and they seem to work with weights. We weight the bags on the beach as they are landed and a person logs that data. The urchins are dumped out onto a sorting table where all the by catch is removed, then the urchins go into barrels and get transported to a local composing site that I have set up. Some people take the urchins for the uni. There is one lady who takes a few buckets to make fabric dye which she dyes beanie hats which are sold on Seatrees.org website. The proceeds go to global environmental projects around the world including ours.
So far since September of 2023 PURP has removed about 23,500 lbs. of purple urchins out of Stillwater Cove.