The myth of invasive lionfish

[Genady]

This picture could be an illustration in my other thread, about the right handed helices of wire black corals. But the lionfish sitting on the helix' axis at 140', 43 m has requested to be here:

 

[Genady]

Here is a study of the lionfish invasion discourse evolution. Turns out that even back in 2015 I was not alone in my doubts, although in a minority. I also represent the "local knowledge" that started to correct the often baseless initial claims.

Quote

ABSTRACT. This study investigates how the lionfish (Pterois sp.) invasion of the Western Atlantic Ocean has been socially constructed by natural scientists, the media, and stakeholders associated with various marine protected areas in the Caribbean. By examining the use of data and metaphors by these actors, I identify where invasion discourses converge and diverge. Although consensus exists regarding the non-nativeness, introduction vector, and successful establishment of lionfish throughout the region, I also identify uncertainty surrounding lionfish impact and controversies regarding lionfish management and control. The dominant discourse frames lionfish as a threat and control efforts as a war to keep the enemy at bay, and promotes lionfish hunting and consumption by humans: the “ultimate predators.” However, this view is challenged by a coalition that questions the safety, effectiveness, and morality of the practices promoted by the kill-and-eat lionfish coalition. A nascent discourse that frames lionfish as fulfilling the role of overexploited native species, primarily expressed in socioeconomic terms, is shifting lionfish impact perception from negative to positive among some stakeholder groups. Whereas the dominant discourse views humans as helping nature to regain balance through lionfish hunting, a minority coalition views lionfish as part of the ecosystem, where a new equilibrium will be reached. This study shows that scientific data and metaphors, amplified by the media, facilitated initial understanding of the lionfish phenomenon and are used to legitimize claims. In time, however, local knowledge and societal values have intermingled with scientific data, sometimes challenging scientific discourses, and contributing to a richer understanding of the invasion as a social-ecological phenomenon.

Carballo-Cárdenas-E..pdf (ncsu.edu)

[Moontanman]

I've been following this "invasion" for many years, home aquarium release is being blamed but at the very beginning it was assumed that a large number of individuals escaped from a public aquarium/lab during a hurricane and the spread began from there. I have no doubt many have been released by thoughtless home aquarists as well. The actual volume of biomass represented by the hordes of large lionfish currently occupying the ocean where there was once nothing but small native fish is very concerning if nothing else. They have even invaded the water of my coastal Carolina area, mostly deep water, but the sheer numbers being caught have only one enduring quality, they are very good to eat. 

Anytime a nonnative species begins to reproduce in huge numbers it is a threat and considered invasive. Sometimes, over long periods of time the ecosystem will find a new balance with the invasive species, European carp are an example of a long established species that still has negative consequences long after it's introduction but it's effect on native populations cannot be ignored even now some 250 years after it's introduction. Asian carp are an example of an evasive that has not, as of this time, settled into the ecosystem and is still very disruptive. Introducing large native predatory fish to the Asian carp's new range that had been hunted to extinction are one of the efforts currently being used to try and control them... alligator gar being one of carnivores of choice.   

Again the unnatural hordes of lion fish are a quite good indicator they are not harmless and native predators are not, for the most part, interested in eating them. That may change as time goes on but for now we are pretty much stuck with them.

BTW, I predicted the Asian Carp invasion, not because I am smart but because I can see the writing on the wall, I was told it could never happen because of hormonal problems caused by some species of native fish that wouldn't allow Asian carp to reproduce in water where the natives lived... never say never. 

Edited February 24, 2022 by Moontanman

[Genady]

5 hours ago, Moontanman said:

I've been following this "invasion" for many years, home aquarium release is being blamed but at the very beginning it was assumed that a large number of individuals escaped from a public aquarium/lab during a hurricane and the spread began from there. I have no doubt many have been released by thoughtless home aquarists as well. The actual volume of biomass represented by the hordes of large lionfish currently occupying the ocean where there was once nothing but small native fish is very concerning if nothing else. They have even invaded the water of my coastal Carolina area, mostly deep water, but the sheer numbers being caught have only one enduring quality, they are very good to eat. 

Anytime a nonnative species begins to reproduce in huge numbers it is a threat and considered invasive. Sometimes, over long periods of time the ecosystem will find a new balance with the invasive species, European carp are an example of a long established species that still has negative consequences long after it's introduction but it's effect on native populations cannot be ignored even now some 250 years after it's introduction. Asian carp are an example of an evasive that has not, as of this time, settled into the ecosystem and is still very disruptive. Introducing large native predatory fish to the Asian carp's new range that had been hunted to extinction are one of the efforts currently being used to try and control them... alligator gar being one of carnivores of choice.   

Again the unnatural hordes of lion fish are a quite good indicator they are not harmless and native predators are not, for the most part, interested in eating them. That may change as time goes on but for now we are pretty much stuck with them.

BTW, I predicted the Asian Carp invasion, not because I am smart but because I can see the writing on the wall, I was told it could never happen because of hormonal problems caused by some species of native fish that wouldn't allow Asian carp to reproduce in water where the natives lived... never say never. 

I have been following this "invasion" for many years as well, starting with the very first appearance of the very first lionfish in our waters in 2009. Our Marine Park management got seriously involved in the research and in the population control attempts of lionfish. They organized many presentations by scientists as well as by other parties interested in this development. And I have witnessed the process directly under water over the years.

"Long term" is the the only issue because there is no stability or balance state of the ecosystem in short term. Every year is different, with or without lionfish. One year, there are unusually many barracudas, other year - "flamingo tongue" snails cover soft corals everywhere, yet others - lobsters, ctenophores, floating sea weed, mass moray die off, etc. etc. There is no base line to compare against in a short term. The ecosystem is highly dynamic and "disruptions" is a norm.

That lionfish got from Florida to Carolinas is understandable. The Gulfstream pushes them that way. But how did they get to the Southern Caribbean? It's a long swim against current...

[Moontanman]

On 2/24/2022 at 10:43 PM, Genady said:

I have been following this "invasion" for many years as well, starting with the very first appearance of the very first lionfish in our waters in 2009. Our Marine Park management got seriously involved in the research and in the population control attempts of lionfish. They organized many presentations by scientists as well as by other parties interested in this development. And I have witnessed the process directly under water over the years.

"Long term" is the the only issue because there is no stability or balance state of the ecosystem in short term. Every year is different, with or without lionfish. One year, there are unusually many barracudas, other year - "flamingo tongue" snails cover soft corals everywhere, yet others - lobsters, ctenophores, floating sea weed, mass moray die off, etc. etc. There is no base line to compare against in a short term. The ecosystem is highly dynamic and "disruptions" is a norm.

That lionfish got from Florida to Carolinas is understandable. The Gulfstream pushes them that way. But how did they get to the Southern Caribbean? It's a long swim against current...

I am not sure you are seeing the tree due to the forest, seasonal variations in fish populations do not match the density of the lionfish populations. In general native fish do not prey on lionfish. This seems to be changing but is takes a quite large predator to eat an adult lionfish, they spread their pectoral fins to make themselves appear much larger than really are. This makes predators view them as too big to eat even if the predator is in fact plenty big enough to eat them. I've seen films that show dozens just swarming a isolated rock in the ocean. Divers can go down and spear hundreds of them in one day and not make a dent in the populations.

I am a certified open water diver, it's been a long time since I dived, but I have seen how fish swarm around isolated rocks and I have never seen fish thickly cover areas like lionfish, not even close btw. The almost absolute lack of the small native fish that normally school around such rocks is probably the most disturbing thing, this indicates the bottom of the food chain has been disrupted. 

I am sure that eventually the ecosystem will absorb these lionfish but is has not happened yet. Native predators will learn to recognise them as food but scientists have told me it is a slow go so far. I've had native octopus climb from one aquarium to another and eat captive lionfish so I know they are not invulnerable but as i said lionfish are good to eat and a fishery has sprung up in some areas and restaurants are listing them on menus so maybe they will prove to be a boon to commercial fishermen in the long run. 

As for invasive species, Florida is famous for it's fresh waters being full of nonnative fishes released by the aquarium industry as well as by home hobbyists. The Florida DNR is also famous for releasing non native fish for their sportfishing industry and tourism... the peacock bass comes immediately to mind.  I tried to lobby for Pseudoscaphirhynchus hermanni to be released into a smallish river in WV that was recovering from years of pollution and fish populations were beginning to recover. In it's own range is is rare and dying out due to habitat destruction. Being so small i thought it would be a great addition to the biodiversity of this river but I was shot down do to the possibility, no mater how remote, that it would become invasive. I guess i should have lobbied for it be released in Florida. 

 

Edited March 1, 2022 by Moontanman

[Genady]

14 minutes ago, Moontanman said:

I am not sure you are seeing the tree due to the forest, seasonal variations in fish populations do not match the density of the lionfish populations. In general native fish do not prey on lionfish. This seems to be changing but is takes a quite large predator to eat an adult lionfish, they spread their pectoral fins to make themselves appear much larger than really are. This makes predators view them as too big to eat even if the predator is in fact plenty big enough to eat them. I've seen films that show dozens just swarming a isolated rock in the ocean. Divers can go down and spear hundreds of them in one day and not make a dent in the populations.

I am a certified open water diver, it's been a long time since I dived, but I have seen how fish swarm around isolated rocks and I have never seen fish thickly cover areas like lionfish, not even close btw. The almost absolute lack of the small native fish that normally school around such rocks is probably the most disturbing thing, this indicates the bottom of the food chain has been disrupted. 

I am sure that eventually the ecosystem will absorb these lionfish but is has not happened yet. Native predators will learn to recognise them as food but scientists have told me it is a slow go so far. I've had native octopus climb from one aquarium to another and eat captive lionfish so I know they are not invulnerable but as i said lionfish are good to eat and a fishery has sprung up in some areas and restaurants are listing them on menus so maybe they will prove to be a boon to commercial fishermen in the long run. 

As for invasive species, Florida is famous for it's fresh waters being full of nonnative fishes released by the aquarium industry as well as by home hobbyists. The Florida DNR is also famous for releasing non native fish for their sportfishing industry and tourism... the peacock bass comes immediately to mind.  I tried to lobby for Pseudoscaphirhynchus hermanni to be released into a smallish river in WV that was recovering from years of pollution and fish populations were beginning to recover. In it's own range is is rare and dying out due to habitat destruction. Being so small i thought it would be a great addition to the biodiversity of this river but I was shot down do to the possibility, no mater how remote, that it would become invasive. I guess i should have lobbied for it be released in Florida. 

 

Well, I was not talking about seasonal variations, but rather about changes in populations from  year to year. And, being a (former) SCUBA instructor with about 3000 logged dives, I see the "invasion" first hand. The bottom line, what I see here is very different from what you describe. Maybe the process is just different in different parts of the ocean, but here we don't see these disturbing things. The lionfish seems to be just another fish in our "aquarium".

BTW, there are many native fishes that are not preyed on by other native predators. For example, nothing eats adult green morays, barracudas, jacks, scorpionfish, rays. This is not something that is special about lionfish, not a factor that makes them different.

Yes, sometimes we find them swarming around a rock. But then there are thousands rocks without them and with plenty of native fish doing there usual things.

[Moontanman]

16 hours ago, Genady said:

Well, I was not talking about seasonal variations, but rather about changes in populations from  year to year. And, being a (former) SCUBA instructor with about 3000 logged dives, I see the "invasion" first hand. The bottom line, what I see here is very different from what you describe. Maybe the process is just different in different parts of the ocean, but here we don't see these disturbing things. The lionfish seems to be just another fish in our "aquarium".

BTW, there are many native fishes that are not preyed on by other native predators. For example, nothing eats adult green morays, barracudas, jacks, scorpionfish, rays. This is not something that is special about lionfish, not a factor that makes them different.

Yes, sometimes we find them swarming around a rock. But then there are thousands rocks without them and with plenty of native fish doing there usual things.

Ok, I acknowledge your experience on this but scientists at NOOA seem to take a different view, possibly the areas with only lionfish and lacking in small fish is a transient phenomena.   

[Genady]

Not a lionfish, but a different invasive fish from the Pacific appeared recently in the Tropical Western Atlantic (TWA) region. Just got this notification:

 

Regal Demoiselle, /Neopomacentrus cyanomos/, a damselfish native to the Indo-Pacific and Red Sea. Experts think that this species was introduced into the TWA by  hitchhiking on relocated oil and gas platforms. It was first reported in the Gulf of Mexico in 2016, and recent reports show that it has expanded its non-native range to southeast Florida.

The species was reported in the Florida Keys in 2020 and has since moved up Florida's east coast to Blue Heron Bridge near West Palm Beach...

Some experts believe that the Regal Demoiselle has the potential to place mild competitive pressure on native fishes, and it is important to track the spread of the Regal Demoiselle to understand the impacts it may have on native species and habitats.

Regal Demoiselle Identification

Similar in appearance to the native Brown Chromis, the Regal Demoiselle is distinguished by a yellow or white spot at the rear base of the dorsal fin, a dark spot behind the gill cover, and yellow or pale rear margins on the fins and tail. In contrast, the Brown Chromis is identified by dark margins on the tail and a dark spot at the base of the pectoral fin. For more information about the Regal Demoiselle, check out this page The Nonnative Regal Demoiselle | Reef Environmental Education Foundation , which also includes a helpful table showing how to tell the difference between it and the native Brown Chromis.

[Genady]

Almost three years after the OP, here is the status. One of the main lionfish hunters got bends while hunting lionfish and left the island long ago together with her partner, the other lionfish hunting champion. Since COVID, lionfish hunting practically has stopped. It is not promoted anymore. The result: no effect whatsoever. The lionfish is there, there is no more and no less of it, as well as the rest of the reef. Evidently, the devastating effect that has been predicted, was in fact a myth.

[Moontanman]

On 3/31/2022 at 3:38 PM, Genady said:

Not a lionfish, but a different invasive fish from the Pacific appeared recently in the Tropical Western Atlantic (TWA) region. Just got this notification:

 

Regal Demoiselle, /Neopomacentrus cyanomos/, a damselfish native to the Indo-Pacific and Red Sea. Experts think that this species was introduced into the TWA by  hitchhiking on relocated oil and gas platforms. It was first reported in the Gulf of Mexico in 2016, and recent reports show that it has expanded its non-native range to southeast Florida.

The species was reported in the Florida Keys in 2020 and has since moved up Florida's east coast to Blue Heron Bridge near West Palm Beach...

Some experts believe that the Regal Demoiselle has the potential to place mild competitive pressure on native fishes, and it is important to track the spread of the Regal Demoiselle to understand the impacts it may have on native species and habitats.

Regal Demoiselle Identification

Similar in appearance to the native Brown Chromis, the Regal Demoiselle is distinguished by a yellow or white spot at the rear base of the dorsal fin, a dark spot behind the gill cover, and yellow or pale rear margins on the fins and tail. In contrast, the Brown Chromis is identified by dark margins on the tail and a dark spot at the base of the pectoral fin. For more information about the Regal Demoiselle, check out this page The Nonnative Regal Demoiselle | Reef Environmental Education Foundation , which also includes a helpful table showing how to tell the difference between it and the native Brown Chromis.

I'm surprised clown fish haven't showed up or invasive corals, spreading animals beyond their native range is one thing humans have been doing since well before records were being kept. Once we domesticated animals and started bringing them with us while we conquered the globe... it's what we do! 

[Genady]

17 hours ago, Moontanman said:

haven't showed up ... invasive corals

They have, e.g., Invasive Cup Coral | Flower Garden Banks National Marine Sanctuary

[Moontanman]

5 hours ago, Genady said:

They have, e.g., Invasive Cup Coral | Flower Garden Banks National Marine Sanctuary

I am behind the times, thanks for posting this!

[CharonY]

On 12/21/2024 at 7:49 AM, Genady said:

Almost three years after the OP, here is the status. One of the main lionfish hunters got bends while hunting lionfish and left the island long ago together with her partner, the other lionfish hunting champion. Since COVID, lionfish hunting practically has stopped. It is not promoted anymore. The result: no effect whatsoever. The lionfish is there, there is no more and no less of it, as well as the rest of the reef. Evidently, the devastating effect that has been predicted, was in fact a myth.

There are a couple of reports out there:

Vallès, H., J. Walcott and H.A. Oxenford. 2023. Assessment and Management of Lionfish and
Status of Other Marine Invasive Species of Threat to High Biodiversity-value Reef Ecosystems.
Draft Final Report. Preventing Costs of Invasive Alien Species (IAS) in Barbados and Countries
of the OECS Project. CERMES, UWI, Cave Hill, Barbados, 53pp

This doesn't seem to include significant post-COVID data from skimming, but from the executive summary:

Quote

Lessons learned include:
vii
(1) The ‘doom-and-gloom’ that was predicted to accompany the arrival of lionfish in Barbados
waters has not materialized, primarily due to the current initiatives in place. Both trap and
spear fishers have not experienced any significant declines in earnings, but have been able to
supplement incomes through the sale of lionfish.
(2) The existing design of traps need not be modified, as numbers of lionfish caught seem to be
more influenced by numbers at a site than the design of the trap.
(3) Non-native sun corals are widely distributed in Barbados on a range of artificial structures,
but do not appear to have spread to natural reef habitat.
(4) Removal of sun coral colonies by scraping appears to be an effective way of controlling their
abundance at least over the short term.
(5) The seagrass, Halophila stipulacea is not present on the island

 

From: Finch, M.W., Ballenger, J.C., Bacheler, N.M. et al. Tracking an invasion: how the distribution and abundance of Lionfish (Pterois spp.) has changed along the U.S. Atlantic coast. Biol Invasions 26, 1669–1683 (2024). https://doi.org/10.1007/s10530-024-03248-y

Quote

Central to invasive species management plans or strategies is monitoring of the population on an appropriate scale, including a characterization of some basic components of the invasion, such as changes in distribution and abundance over time. This is true of the invasive Lionfish (Pterois volitans and P. miles) in the Atlantic waters off the southeast coast of the United States, where they have become established, but minimal information regarding region-wide metrics of long-term abundance and distribution exists. By utilizing videos from 2011 to 2021 from a fishery-independent survey, regionwide distribution and abundance trends were characterized with generalized additive models, using spatial, temporal, environmental, microhabitat features, and water property variables to explore their effects on these patterns. The probability of occurrence and relative abundance of Lionfish in the study area increased initially until reaching a peak in 2015–2017 and then declined to the end of the study period (2021). Lionfish distribution and relative abundance followed similar patterns throughout the time series, but there was no extension north or south in the region, indicating abundance levels were driven by the density of Lionfish and not changes in distribution. The same variables were identified in both models, indicating preferred habitat use and/or detectability of Lionfish can be accounted for in continued monitoring efforts and provide information for future mitigation efforts.