The myth of invasive lionfish

[Genady]

Since appearing in our area about 15 - 20 years ago, the invasive lionfish became a common resident on our reefs. Contrary to the wide-spread anti-lionfish propaganda about its many dangers to the local marine environment, such as "Nothing eats lionfish", "Local fish don't know that it's a predator", "It eats everything", "It multiplies uncontrollably", etc., it did not cause any damage to the coral reef or to its inhabitants. It rather found its eco-niche and lives peacefully with - i.e. eating and being eaten by - other fishes. It added an exotic element to our underwater experience, though.

Please meet - the lionfish:

Edited February 9, 2022 by Genady

[beecee]

Undeniably along with coral bleaching, the greatest danger to Australia's Great Barrier Reef, is the "crown of thorn starfish" 

https://www.barrierreef.org/the-reef/threats/Crown-of-thorns starfish

 

[Genady]

3 minutes ago, beecee said:

Undeniably along with coral bleaching, the greatest danger to Australia's Great Barrier Reef, is the "crown of thorn starfish" 

https://www.barrierreef.org/the-reef/threats/Crown-of-thorns starfish

 

It is not invasive, is it?

[beecee]

3 minutes ago, Genady said:

It is not invasive, is it?

Yes it is as far as I know. Will do some checking in the meantime.

4 minutes ago, beecee said:

Yes it is as far as I know. Will do some checking in the meantime.

Seems I maybe wrong.........................

https://phys.org/news/2019-02-dreadful-discovery-crown-of-thorns-starfish-silver.html

extract:

"The crown-of-thorns is an infamous pest, responsible for the loss of immense stretches of coral throughout the Indo-Pacific region, especially on Australia's Great Barrier Reef. It's been the object of concern and media exposure for a couple of decades. Many people assume that because it does so much harm, the crown-of-thorns must be an invasive species, but it's not.

"It's native to the Pacific," Allen said. "They're widespread and we now know that there are four species."

[Genady]

1 hour ago, beecee said:

Yes it is as far as I know. Will do some checking in the meantime.

Seems I maybe wrong.........................

https://phys.org/news/2019-02-dreadful-discovery-crown-of-thorns-starfish-silver.html

extract:

"The crown-of-thorns is an infamous pest, responsible for the loss of immense stretches of coral throughout the Indo-Pacific region, especially on Australia's Great Barrier Reef. It's been the object of concern and media exposure for a couple of decades. Many people assume that because it does so much harm, the crown-of-thorns must be an invasive species, but it's not.

"It's native to the Pacific," Allen said. "They're widespread and we now know that there are four species."

If they are right and the eutrophication is the main cause of the COTS' population explosion, then I don't know what you guys can do about it. Corals vs agriculture, hmm...

At least we don't have that problem here. All the rest, yes - warming, acidification, overfishing, mechanical damage to the reef by boats and divers, - but not eutrophication.

[beecee]

18 minutes ago, Genady said:

If they are right and the eutrophication is the main cause of the COTS' population explosion, then I don't know what you guys can do about it. Corals vs agriculture, hmm...

At least we don't have that problem here. All the rest, yes - warming, acidification, overfishing, mechanical damage to the reef by boats and divers, - but not eutrophication.

While significant damage has already been done, it as been found that injecting vinegar into the COTS will kill them. It is though time consuming as each COTS is injected individually with this vinegar mixture by trained divers, to avoid harming the surrounding system.

https://www.barrierreef.org/the-reef/threats/Crown-of-thorns starfish#:~:text=Crown-of-thorns starfish control,t harm the surrounding ecosystem. 

Edited February 9, 2022 by beecee

[Genady]

1 hour ago, beecee said:

While significant damage has already been done, it as been found that injecting vinegar into the COTS will kill them. It is though time consuming as each COTS is injected individually with this vinegar mixture by trained divers, to avoid harming the surrounding system.

https://www.barrierreef.org/the-reef/threats/Crown-of-thorns starfish#:~:text=Crown-of-thorns starfish control,t harm the surrounding ecosystem. 

Do the numbers work out? Population and population growth of the COTS on one hand, number of trained divers and their rate of injecting the COTS on the other? Will it make even a dent in the COTS population?

Divers kill lionfish in this part of the world, but it doesn't make any difference in the lionfish numbers. It tastes good, though.

[beecee]

11 minutes ago, Genady said:

Do the numbers work out? Population and population growth of the COTS on one hand, number of trained divers and their rate of injecting the COTS on the other? Will it make even a dent in the COTS population?

Divers kill lionfish in this part of the world, but it doesn't make any difference in the lionfish numbers. It tastes good, though.

Good question. All I can say, is I hope so. Otherwise we may lose one of the seven natural wonders of the world.

[Genady]

A slow dance with a quick ending. So much to the "Nothing eats lionfish" slogan. This video: 

 

[dimreepr]

 

[Genady]

23 minutes ago, dimreepr said:

 

Wrong thread?

[dimreepr]

3 minutes ago, Genady said:

Wrong thread?

Is it?

[Genady]

Just now, dimreepr said:

Is it?

I don't know. Can you explain?

[dimreepr]

1 minute ago, Genady said:

I don't know. Can you explain?

Change is inevitable, the lionfish isn't...

[Genady]

Just now, dimreepr said:

Change is inevitable, the lionfish isn't...

Would be helpful if the post comes with some explanation about what it is doing in  the thread, so others don't need to check the link if they're not interested. I think, it is also a rule here.

Anyway, is there anything about lionfish or invasive species in the video? What?

[dimreepr]

2 minutes ago, Genady said:

Would be helpful if the post comes with some explanation about what it is doing in  the thread, so others don't need to check the link if they're not interested. I think, it is also a rule here.

Anyway, is there anything about lionfish or invasive species in the video? What?

The rule here is, attack the argument, not the lionfish...

[Genady]

1 minute ago, dimreepr said:

The rule here is, attack the argument, not the lionfish...

Which argument are you attacking?

[dimreepr]

1 minute ago, Genady said:

Which argument are you attacking?

The myth of invasion... 

[Genady]

4 minutes ago, dimreepr said:

The myth of invasion... 

OK. I only wish you would make it clear in that post. I cannot watch the video you've linked, but wanted to know what was your message. Have a good day.

[dimreepr]

8 minutes ago, Genady said:

OK. I only wish you would make it clear in that post.

If I could, I would... 

 

[CharonY]

I wonder whether that is really a myth. Or conversely, are there studies that indicate that lionfish are non-disruptive for the ecosystems they got in? A quick google seems to indicate a fair number of studies where they seem to indicate significant damages. That being said, these were mostly a few years old already and it would be interesting to see what the current state of science is on that matter.

One of the newer ones for example: https://doi.org/10.1080/03632415.2017.1340273

Quote

Species invasions in marine ecosystems pose a threat to native fish communities and can disrupt the food webs that support valuable commercial and recreational fisheries. In the Gulf of Mexico, densities of invasive Indo-Pacific Lionfish, Pterois volitans and P. miles, are among the highest in their invaded range. In a workshop setting held over a 2-week period, we adapted an existing trophic dynamic model of the West Florida Shelf, located in the eastern Gulf of Mexico, to simulate the lionfish (both species) invasion and community effects over a range of harvest scenarios for both lionfish and native predators. Our results suggest small increases in lionfish harvest can reduce peak biomass by up to 25% and also that reduced harvest of native reef fish predators can lead to lower lionfish densities. This model can help managers identify target harvest and benefits of a lionfish fishery and inform the assessment and management of valuable reef fish fisheries.

 

[Genady]

The old studies were small, short, and not convincing. This newer study is 5 years old, and it still only claims that the lionfish "pose a threat" and "can disrupt." It doesn't show that it actually does. It is an assumption of the study and a justification for it. Plus, it is a simulation, in one locality, and only regarding effects of harvest on the lionfish population (on the assumption that we want to reduce it). What does it show? It shows that if we harvest lionfish more, then their numbers will decrease (hardly unexpected). And, if we harvest native predators less, then the lionfish numbers will decrease. The latter in fact shows that there are native predators of lionfish!

What I see on the grounds here, in Southern Caribbean is, no long term effect, no observable damage to the reef ecology. That's why I suggest it is a myth.

  

[CharonY]

24 minutes ago, Genady said:

What I see on the grounds here, in Southern Caribbean is, no long term effect, no observable damage to the reef ecology. That's why I suggest it is a myth.

So is there data out there that would suggest either? Because most reports I can find on Lionfish does indicate that there are efforts underway to control them and I am unable to find reports indicating that they are mostly non-disruptive. Sure, it is possible that the worries were overblown, but before declaring it a myth, I would like to see some evidence. And if I scan lit on the Southern Caribbean I see a number of efforts to cull them (https://www.forbes.com/sites/daphneewingchow/2022/01/31/the-caribbean-is-taking-a-bite-out-of-its-invasive-lionfish-problem/?sh=648af9cb5e8f) There several papers that try to investigate the impact and cost of lionfish management, e.g. DOI:10.1007/s00227-015-2745-2 and a number of agencies, including NOAA seems to spend quite a bit of efforts on controlling this species, too: https://www.fisheries.noaa.gov/southeast/ecosystems/impacts-invasive-lionfish

So at least that makes it strange that apparently either no one picked up on the fact that they are harmless (and spending a lot of money on it) or at least I cannot find reports on that.

[Genady]

I read these stories and I think they are just reprints from 10 and 20 years ago. All the same claims, perhaps in the same words. No new evidence, one way or another.

Why people and organizations do what they do? I can come up with numerous reasons. I am sure, you can too. The most innocent being, better safe than sorry.

I think it is difficult to show that something has no effect. It is usually a null hypothesis. Anyway, after some 30 years and the wide range of invasion, where is the damage? It supposed to be big. I cannot find reports on that.

 

[Genady]

In this picture, a lionfish and a sea urchin share a rock for food and shelter: