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Comment by nradov | Hacker News Reader

I have been diving in the Monterey, CA region since 1999 and have seen the change first hand. Sunflower sea stars are now extinct in the area; I haven't seen one in years. Some of the smaller sea star species have started to gradually recover but they aren't effective at preying on purple urchins. There is a local group culling urchins but they'll only be able to cover a small area.

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Same thing in British Columbia: over 90%, 5.7 billion have died since 2013 [1].

When I was a kid in the 90s, and starting to dive in the 2000s, sea stars were everywhere on the ocean floor, even really close to the city center of Vancouver. They were so ubiquitous that they were completely uninteresting to us locals. We would hear that BC was considered world-renowned for scuba diving quality, and think "How dull, it's just a shit ton of sea stars"

(Of course, we were young, stupid, and also called them starfish not sea stars then)

Me and some friends would go camping at an oceanfront spot on Vancouver Island every year, and go crabbing with mixed results. Half of the irritation was sometimes you'd be pulling up what felt like a really heavy crab trap full of goodness (We were always responsible and only kept the males over the legal size), only to find it full of sea stars who chased away the crabs and ate our bait.

Then, about six or seven years ago, the sea stars just...disappeared. And they didn't come back.

[1] https://www.cbc.ca/news/canada/british-columbia/sunflower-se...

I remember my partners parents saying the same about star fish population around Hornby island. The time frame matches up as well.

Please consider taking the time to add your historic observations to https://inaturalist.org/

I appreciate the suggestion but I would rather focus on gathering data for Project Baseline Point Lobos which is tracking changes at one specific area near Monterey.

http://db.projectbaseline.org/?c=USA&p=11&s=1M

Thank you for sharing this. I literally got open water certified in Monterey this afternoon, and I will be signing up to volunteer!

I've clearly been doing this quarantine / pandemic wrong.

You still have time. sigh

I am very excited for the results of the urchin culling experiment Fish and Wildlife has allowed in Monterey. There is debate in the scientific community if allowing the public to kill urchins will hurt or help the cause.

Many divers in the area (mostly from out of town) think they can help the kelp forests by smashing them with whatever tools they can. I have even found a lost hammer while diving a popular site in Monterey.

While smashing effectively ends the life of the urchins, it also releases their spawn and can cause a even worse environmental disaster. It is also not an effective solution for the whole coast and will only work to clear areas frequented by divers.

> it also releases their spawn and can cause a even worse environmental disaster

Wouldn't the spawn be released anyway? I can see how this strategy would be ineffective, but how is it worse?

They are probably pointing out that there could be a better way to kill/remove/move the urchin without releasing the spawn.

Although it's very hard to get them off their spot and handling them.

Why not combine reducing their number with supplying a "new" market for those who enjoy eating them? https://triedandsupplied.com/saucydressings/how-to-eat-sea-u...

NZ has a similar problem with urchin ("Kina", in NZ) barrens. The urchins in NZ urchin barrens, as in CA, are malnourished and are subsequently difficult and unproductive to eat as they contain very little actual meat.

I surf in the Monterey bay almost every day and the bull kelp is as thick as it's ever been.

Are you saying the data gathered over the last 20 years is wrong?

The article doesn't discuss Santa Cruz county/Monterey Bay. Shoo!

The article discuses the entire Northern California coast.

Are the local purple urchins edible?

https://www.splendidtable.org/story/2018/07/26/why-we-should... Perhaps yes, but I doubt that can undo the damage done without an overcorrection and more issues.

This is the sad state of humans trying to help or fix mother nature. In almost every instance, the fix results in one of those "oh, didn't think of that" kind of things. I don't know the lady swallowed the dog to chase the cat to catch the bird to eat the spider to catch the fly. It's a literal nursery rhyme we teach kids.

While that is true of trying to introduce new species to predate over-populated species (or really any novel species introduction), there is a long history of humans successfully managing their own predation to help balance over/under populated species. Obviously we have had failure in this area too but it we do know it is possible for us to do it and improve things.

Survivorship bias, humans make corrective actions to local environments all of the time and there are no noticeable issues. When something goes wrong it’s news though.

We have minimal if any data about how many of the course corrections go well, precisely for that reason. However because we don’t know how many there are, it’s not accurate to claim to know it’s survivorship bias. It could be that, but it could not be. There’s not enough data to make a conclusion.

Disagree - ecologists are specifically categorized as wicked problems (as opposed to ‘tame’ problems like say chess) because they are complex and you never know where the fallout is going to be.

We know if the disasters because we see them go wrong more often than not.

Survivorship bias applies more to things like CEO success stories, startup success stories and sports personalities.

A tiny fraction make it big, and these get studied/reported on.

https://en.wikipedia.org/wiki/Wicked_problem

Technically yes some divers do eat them, but these aren't the same species of urchin that people typically eat as uni sushi. The gonads in purple urchins are so small that's it's hardly worth the effort of cleaning them.

Yes I've taken some home from the beach and they're just fine. The eggs turn into ooze pretty quick so I don't know how viable they'd be commercially.

Wouldn't solve the problem necessarily.

We need more experts and more resources in ecology to detect the main problems, otherwise we could be like a dog chasing its own tail. The problem can be predation, but also could be contamination, or just two degrees more in water temperature blocking the settlement of the tiny "kelpings".

Do you know if they've looked at trapping the urchins? I believe traps are used to harvest urchins elsewhere and it works ok.

Have they been migrating north like the lobsters on the East Coast?

Purple urchins have long been common in the northeast Pacific Ocean as far as British Columbia. They're not migrating any further north but the population has increased because the ecosystem is out of balance.

I feel like we’d have to check around hard to reach places to see if them being gone means dead or if they just adapted and migrated to other areas or deeper seas etc.

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