Urchin cull approved for Monterey reef

[MichaelMc]

@Bigbella Can you easily create spawning in those you crush, wound catastrophically and fatally, or in their neighbors? What fraction spawn? Injuring or injecting are not much of the dive plan.

What happens when otters or sea stars eat them? What fraction spawn?

What happens if they live til next year's breading season, and the ones after that. What fraction spawn each year? How many times each year?

Does, induced, spawning out of 'season' have a lower survival rate?

(Do we have video of single urchins spawning and of the area around culled urchins for comparison?)

 

[Eric Sedletzky]

Not to belabor the point; but I still think that this culling effort, by destroying urchins, will simply magnify the problem; become an absolute nightmare. Without their physical removal to a compost heap, this will prove to be a fool's errand.

To give some perspective, urchins are already sexually mature at about 25 mm -- tiny; can live upwards of thirty years, if left to their devices; and while there is a general breeding period, from Washington to Northern Baja waters (roughly September through May) -- large reproductive populations are often found through July; they remain capable of breeding, by broadcast spawn -- often as a stress response.

Hammering neighbors to oblivion certainly strikes me as a stressful event; and I've witnessed concurrent spawn as a result of hammer-culling efforts, in the past. Environmentally, they only seem chemically sensitive to chlorine, at 0.05 ppm, which serves to immobilize the sperm; and frequent die-offs occur near sewage outfalls, where it is commonly used as a disinfectant, in treated effluent.

Private culling efforts at Sea Ranch, Salt Point and environs, over the last two years, simply produced a massive young-turk population of 20-25 mm breeding urchins, on their previously denuded real estate, as I had witnessed last January.

Additionally, we were easily able to achieve urchin fertilization last Wednesday, at our office, from supposedly non-breeding samples collected the previous weekend; nothing sophisticated -- the equivalent of middle school science taught by a apathetic P.E. teacher,

Variously, we injected a few with 0.5M KCl; injured a couple; and others, injected with 7-10 ml of air. All were actively spawning within a minute -- looked like the last reel of Caligula. We later saw characteristic evidence of radial holoblastic cleavage, within hours, under light microscopy.

We supply urchins for bioassay purposes, through most of the year; and I' can give you a guess why: because they still capable of spawning; or they wouldn't be shipped; and this initial fertilization crap can even be left to an intern, the slow one, almost incapable of reading the hashmarks on a syringe; it's that simple . . .

Is this the official final word science straight from the horses mouth?
If it is then this is excellent.
Removing urchins would be fine, I just need to know which it is and for the official people to make up their minds, then stick to it!!!
I feel like I’m getting jerked around here.
Half say cull, half say remove, which one is it?!
Maybe I should just ditch this scene and find out for myself finally and positively, then continue on independently and do my own work in my area.
All we’re doing here is just going in circles.
This is becoming a waste of time.

 

[runsongas]

@Eric Sedletzky g2kr.com has more info, but it is being run by Keith who also is part of Reef Check. you do not have to take the class to help, if you want to just show up and smash some urchin with a valid fishing license, you can do so from the gray buoy outside of the survey area marked off with yellow buoys.

 

[Eric Sedletzky]

Full disclosure, I am really excited to take the class.

Some folks believe it is really important to make sure the intervention one is making in a natural system is effective in achieving its primary purpose, while minimizing side effects. I think that takes more than 30 minutes of training. It’s a different model than Mendocino, you can call it elitist if you want.

As for the cost, I’d say it’s the same market as folks who buy your acclaimed artisanal backplates. If they can afford $500 for a backplate that’s not being produced anymore and a wing that is out of stock for months at a time, they can afford a $300 class. It’s not like any of the dive ships or instructors are making money hand over first. They mostly seem to be going out of business. It’s worth it to me to scientifically do a cull and learn something about the effect of the intervention on a large scale.

If you want to take the class, knock yourself out and have a great time! I’m happy for you.

Leave my plate out of this, it has nothing to do with culling urchins just like any other gear has nothing to do with it. I’m not manufacturing some high dollar hammer to cull urchins so fagedaboutit.
The reason I’m not making plates right now is because it’s a pain in the ass, I don’t make that much on them, and stainless is through the roof right now, plus I don’t have time.
Besides, 99% of the plates leave the state mostly going to the Midwest, east coast, south, and the rest sprinkled around the globe. Very few in Cali and even fewer in the Bay Area, so no it’s not the same people taking the class. I’ll bet most of those folks are in H gear which BTW costs more than my stuff.

 

[Chavodel8en]

@Eric Sedletzky g2kr.com has more info, but it is being run by Keith who also is part of Reef Check. you do not have to take the class to help, if you want to just show up and smash some urchin with a valid fishing license, you can do so from the gray buoy outside of the survey area marked off with yellow buoys.

This here may be a good way to get folks involved. Its not just the cost of the class, folks may not have the time or patience to attend an in person class. They want to start smashing urchins!! It may picque their interest and they may step their participation up. I will probably start by getting a license and a hammer (thanks for the link) and doing the untrained culling. A video tutorial would be helpful. I understand we dont want to hurt other things.

 

[Bigbella]

For those who fail to believe that the urchins are in breeding condition, here is a nice marcro shot of a purple urchin from Lover's Cove, from this morning, at about 10 meters -- chowing down on some Iridea, from its appearance. It was clearly spawning; was not alone; and I did nothing whatsoever, to elicit that response. Perhaps, it's the warmer summer waters, producing stress; but it was like Caligula out there . . .

Here too, is the "coral" of urchin, in ice water -- shortly to be in a pasta dish -- pasta vicci . . .

 

[MichaelMc]

So your point is they are spawning anyway no matter what we do?

It seems these issues remain:

What fraction spawn if they are crushed, wounded catastrophically and fatally, or their neighbors?

What happens when otters or sea stars eat them? What fraction spawn?

What happens if they live til next year's breading season, and the ones after that. What fraction spawn each year? How many times each year?

Does spawning out of 'season' have a lower larval survival rate?

 

[runsongas]

if they are removed from the water before they can spawn, it possibly could help. but the north coast removals by the watermen's alliance don't seem to have made much of a dent to date.

anyone know if the captive breeding of sunflower stars is going any better?

 

[Bigbella]

So your point is they are spawning anyway?

It seems these issues remain:

Can you easily create spawning in those you crush, wound catastrophically and fatally, or in their neighbors? What fraction spawn?

What happens when otters or sea stars eat them? What fraction spawn?

What happens if they live til next year's breading season, and the ones after that. What fraction spawn each year? How many times each year?

Does, induced, spawning out of 'season' have a lower survival rate?

Yes, you can induce them to spawn by injuring them -- a common method and occurrence, under laboratory conditions.

When I worked the labs, we either injected them with 0.5M HCl; air; or, most commonly, destroyed one or two urchins; and within minutes, the neighbors in the tanks were induced to spawn -- obviously, water-borne chemical alarm signals, of one form or another, from injured conspecifics.

"What happens when otters or sea stars eat them? What fraction spawn?

Sea stars and otters entirely devour the soft parts of the urchin -- gonads included. That animal -- those animals, by definition, will no longer spawn. They've been "removed." The gametes son't survive the digestive tracts of either animal.

An overwhelming percentage of sexually mature -- 25 mm and above -- sea urchins will spawn; not a matter of mood, or playing Sinatra; but a chemical / hormonal cue in the water, since they broadcast spawn. The cues that stimulate gametogenesis are not well understood but a primary cue is thought to be changing photoperiod. Spawning triggers are largely unknown; but 1˚ cues are believed to be temperature and environmental factors; algal blooms (which we are experiencing) and storms (currently out of the picture).

Since there is no discreet season, depending upon the population, who is to know the success rate, one way or another; save to say, that they dependably develop rapidly in the lab, almost year-long, which is why they are so commonly used, for research . . .

 

[MichaelMc]

destroyed one or two urchins; and within minutes, the neighbors in the tanks were spawning -- obviously, chemical alarm signals, of one form or another, from injured conspecifics.

How big is the tank? Does that happen in the ocean?

Do they spawn if you crush them catastrophically, not just wound?

When eaten, are they spawning til the gonads are all eaten?

It still sounds like they spawn anyway eventually and repeatedly no matter what we do.