Lionfish Awareness and Elimination

[annieols]

Wow I cant believe all this conversation since i was last online! i really enjoyed reading everyones opinions (mostly)

But seriously i respect and appreciate all of the different points of view you have put forth, even the ones i disagree with...

Scientists believe that the lionfish invasion could become the most disastrous marine invasion in history due to the high reproductive rates of lionfish, their widespread distribution, and adaptability to a variety of shallow and deep-water. Lionfish have the potential to disrupt delicate coral reef communities because they are voracious predators that out-compete many native species for food resources, resulting in decreases in fish abundance and diversity on reefs where they become established.

Sadly, scientists have concluded that the lionfish populations will continue to grow and cannot be completely eradicated using conventional methods. Because of their extensive geographical range, diversity of habitats and the depths they occupy, any major attempts to eradicate existing lionfish populations would be impractical and doomed to failure. Control seems to be the only option left at this time. As divers who want to continue to enjoy the underwater environments in the Caribbean and Atlantic, we have a responsibility to help in elimination efforts and to stay active and informed about lionfish.

One thing that i dont really like so much is missinformation I strongly suggest that those of you really interested in learning about lionfish, their invasion into the caribbean and the chances we have to help eliminate them read
Dr. Morris’ doctoral dissertation (Morris Jr., J.A. The Biology and Ecology of the Invasive Indo-Pacific Lionfish [doctoral dissertation]. [Raleigh (NC)]: North Carolina State University, 2009. 168pp.). It is an amazingly comrehensive scientific text (even if a little dry at times)

Sorry to call you out specifically, but in the texts and journals i read this

Juvenile lionfish do not inhabit reef structure, they drift in the open ocean for the first 10 months of their life. I strongly suspect they are drifting in the Sargasso weed as this would explain their juvenile coloring, provide an ample supply of shrimp and explain their ability to colonize new reef 'upstream' of the drift. (Wind will move the weed mats more strongly than the currents).

just wasnt true.

Lionfish can reach sexual maturity within one to two years, after which they can reproduce several times per month. Each spawning event can produce up to 30,000 eggs, which leads to an estimated two million eggs per year.

Lionfish courtship, which begins shortly before dark and extends well into the night, is an intricate display of circling, side winding, following, and leading. After courtship, the external fertilization begins; the female ascends towards the surface and releases two buoyant egg masses, which are fertilized by the male as they float to the surface.

Eggs are bound in adhesive mucus, which disintegrates into free-floating larvae within a few days. Larvae can float for as long as 26 days before hatching and settling, leaving a significant amount of time for the larvae to be dispersed over wide areas via oceanic currents (Gulf Stream, Gulf of Mexico Loop current, and Caribbean current).

 

[annieols]

Fred R. if you have a sited reference for your 10 month statement i would really love to read it, as it contradicts the research i read

 

[redacted]

Sorry to call you out specifically, but in the texts and journals i read this
Quote:
Originally Posted by Fred R. View Post
"Juvenile lionfish do not inhabit reef structure, they drift in the open ocean for the first 10 months of their life. I strongly suspect they are drifting in the Sargasso weed as this would explain their juvenile coloring, provide an ample supply of shrimp and explain their ability to colonize new reef 'upstream' of the drift. (Wind will move the weed mats more strongly than the currents)."
just wasnt true.

Lionfish can reach sexual maturity within one to two years, after which they can reproduce several times per month. Each spawning event can produce up to 30,000 eggs, which leads to an estimated two million eggs per year.

Lionfish courtship, which begins shortly before dark and extends well into the night, is an intricate display of circling, side winding, following, and leading. After courtship, the external fertilization begins; the female ascends towards the surface and releases two buoyant egg masses, which are fertilized by the male as they float to the surface.

Eggs are bound in adhesive mucus, which disintegrates into free-floating larvae within a few days. Larvae can float for as long as 26 days before hatching and settling, leaving a significant amount of time for the larvae to be dispersed over wide areas via oceanic currents (Gulf Stream, Gulf of Mexico Loop current, and Caribbean current).

I don't see any conflict in the two quoted statements. They are not saying the exact same thing but they seem entirely compatible - no disagreement, no conflict.

 

[highlandfarmwv]

The ocean sunfish (theat big on that looks like a big head with no body) is its natural predator in the Indian and Pacific oceans; none in the Atlantic.

 

[annieols]

I don't see any conflict in the two quoted statements. They are not saying the exact same thing but they seem entirely compatible - no disagreement, no conflict.

The other poster said (and i paraphrase) that juvinile lionfish are not found on the reef because they float for 10 months, in my research I found that lionfish larvae hatch and settle within a month (or slightly less)- this is a huge time difference, especially since new research is starting to show that the time that it takes for a lionfish to reach sexual maturity is actually less than first thought (from 2 years to one year).

It is the extreme reproductive abilities of lionfish (coupled with other factors such as diverse habitats and voracious appetites) that make them so overwhelming from an elimination standpoint. I just was trying to express that the other poster might have his times a little off.

The other problem with misquoting the time it takes for Lionfish larvae to settle is the area over which these larvae are dispersed. Having one month to ride the currents is a whole lot less than 10 months previously quoted. There are quite detailed scuentific models showing the possible future distribution of lionfish based on one month as the settling time.

further, if lionfish larvae are settling every month (or so) it allows for more rapid establishment of new populations; which could lead to desner populations over larger areas.

Im a about lionfish at the moment, sorry

 

[redacted]

The other poster said (and i paraphrase) that juvinile lionfish are not found on the reef because they float for 10 months, in my research I found that lionfish larvae hatch and settle within a month (or slightly less)- this is a huge time difference, especially since new research is starting to show that the time that it takes for a lionfish to reach sexual maturity is actually less than first thought (from 2 years to one year).

It is the extreme reproductive abilities of lionfish (coupled with other factors such as diverse habitats and voracious appetites) that make them so overwhelming from an elimination standpoint. I just was trying to express that the other poster might have his times a little off.

The other problem with misquoting the time it takes for Lionfish larvae to settle is the area over which these larvae are dispersed. Having one month to ride the currents is a whole lot less than 10 months previously quoted. There are quite detailed scuentific models showing the possible future distribution of lionfish based on one month as the settling time.

further, if lionfish larvae are settling every month (or so) it allows for more rapid establishment of new populations; which could lead to desner populations over larger areas.

Im a about lionfish at the moment, sorry

I guess I am still unclear. Fred says "Juvenile lionfish do not inhabit reef structure, they drift in the open ocean for the first 10 months of their life." You are citing a reference that says, "Eggs are bound in adhesive mucus, which disintegrates into free-floating larvae within a few days. Larvae can float for as long as 26 days before hatching and settling". I read this to mean that they float for about a month before they hatch and become juvenile LF and then they settle in structures in surface waters for 10 more months. It probably does not matter that much whether they essentially travel with the surface winds and currents for a month or 30 months in terms of distribution. Both time periods should carry new LF to fairly distant waters before they make the move to their adult habitats. The very rapid spread of LF through the Caribbean attests to a high degree of mobility at some point in their life. So the underlying effect is not the issue. LF eggs produced in Bonaire, for example, are unlikely to end up as part of the adult LF population in Bonaire.

But the idea that his description "just wasn't true" does not seem to be justified. Your claim leaves me wondering if this is an attempt to discredit his hypothesis that LF may, in fact, be beneficial to corals and some other reef creatures. It is an interesting and different concept.

 

[annieols]

I made no comment about freds hypothesis that LF may actually be beneficial to corals. Though i have a hard time believing he could support such a claim, I think persuing all possible hypotheses can only lead to beneficial outcomes. I applaude his personal interest in lionfish and was only asking for the sources he has which says lionfish juviniles stay on the surface for 10 months.

I admit that i am no expert, but i have read several expert texts over my personal research in the last few months and have seen nothing to support this claim. Everything i read says that after eggs hatch into larvae (this is a short process, a couple days only) the larvae become free floating. They float for approximately one month before settling on the reef.

If fred has documentation which says something different, i would like to know- I want to adjust my thoughts and teachings... I am not trying to dicredit his hypothesis. He will either prove it or discredit it on his own should he choose to do research on it.

 

[DeepSeaOne]

Another interesting thing happened in the early 90's that coincides almost precisely with the apparent reduction in reef fish population and LF explosion...

An electronics explosion...The introduction of cheap, affordable, and highly accurate GPS units, fish finders, and radar units that the average sport fisherman could afford. Now everyone with a boat and a credit card could put themselves right on the reef (and the fish). A feat that once required a professional fisherman with local knowledge. GPS was a MAJOR leap in technology for the novice fisherman.

 

[Fred R.]

I first started seeing lionfish on the local reefs in 2005. I reported it to the Bahamian Government and the other local dive ops, along with pictures. Scientists report the first sightings in our area to 2006, which means to me that they weren't paying attention.

I went to DEMA, where the lionfish invasion was all the buzz and tried to learn all I could. It was apparent that not a lot was known about these fish so I set out to learn more on my own. At that DEMA my one important question, asked of all the people presenting information was "Where are the little ones?". The director of the Bermuda Aquarium answered me, "They are really small" DUH!!!

It was there that I got the impression that they drifted for a long time and 10 months is what stuck in my mind. I checked your reference and it comes down to a single study of 5 larval lionfish in NW Australia that estimated settlement by fin development.

So I would ask you, Annieols, the same question; where are all the little ones? For five years now, I have been wondering and searching for that answer.

The first lionfish I found in our area was a 60-70 mm specimen. It was hiding under a bit of wreckage. I spotted it from over 50 feet away by the tips of its pectoral fins sticking out. I tried to point it out to my wife who didn't see it even when my finger was only inches away from it, so I coaxed it out of hiding with the tip of my knife.

I've never seen a young lionfish smaller than 50-60 mm. I track all sorts of things down to my limits of perception. According to the article you referenced, the lionfish settle at 14 mm, or about half an inch. That is quite large compared to some other things I track (try finding juvenile Xanthid crabs at 1mm and you'll see what I mean)

Scuba divers have reported young lionfish in the Sargasso weed. Since I can't find them on the substrate, I have to assume they are probably living in the weed. This makes sense for several reasons, their young coloring would hide them, the weed supports a large population of small crustaceans which is reported to be the choice of juvenile diet, and large lionfish cannibalize small ones. The reef would be the worst place to be for a 14-70 mm lionfish.

BTW-when I say I have never seen one smaller than about 60 mm, I've really looked. I've looked in shallow off shore sites, reef at every depth from 1 meter to 70 meters. I've looked inland, in harbors and mangroves. I can find big ones everywhere, but even turning over rocks and roots, I can't find the really small ones.

I've found breeding aggregations of up to eleven lionfish at 70 meters, I seriously doubt you or anyone else will be down that deep effectively reducing their numbers.

Many people's comments keep coming back to the reproductive capability of lionfish. First of all, ALL reef fish have similar reproductive numbers, that does not make the lionfish evil. If the numbers are correct, big 'if', and the juveniles settle in 26-40 days, we would be up to our hip in small lionfish. They should be as easy to find as small damsels, silversides, or rough head blennies.

Secondly, ALL the reef fish eat all they can, whenever they can. If you want to observe a relentless hunter slaughtering small fish, follow a trumpet fish around.

So, please question my numbers, questioning is what every good scientist does. Also question all these scientist that reference a study with only five lionfish juveniles, who may not have settled, but may have been lost, or trapped by the current they were following.

And Please, please, question anyone who says that any living thing is bad and must be killed on sight. I am not saying (oh I can hear the flames now, smallpox, Dracunculiasis, anopheles, etc.) that there aren't things that should be eradicated for the greater good, just question before you attempt it.

If you would like a reference, I don't know if you've seen;

http://www.e2ccb.org/webpages/gdole/files/LionFish.pdf
It briefly mentions that the success of the lionfish could have been enabled by overfishing of possible competing species.

Also, on topics of coral reefs, the NOAA hosted forum;
The Coral-List Archives

One of the scientists who does research from one of the Bahama islands just noticed that the algae had disappeared from his area. Of course, during the time he was away, writing, teaching or whatever, I did about 700 dives watching the changes that led to the algae disappearing.

And to awap; The mid '40's was the start of the baby boom. Mashed bananas were recommended by doctors as the best first food for babies during that period. (I'm a boomer, and my mother kept records of all things 'me' including formulas and the doctor's advice) In the days before Gerber's, bananas were easy to prepare and becoming readily available as shipping improved. Correlation? Cause and Effect? Just sayin...

 

[bubba105]

Another interesting thing happened in the early 90's that coincides almost precisely with the apparent reduction in reef fish population and LF explosion...

An electronics explosion...The introduction of cheap, affordable, and highly accurate GPS units, fish finders, and radar units that the average sport fisherman could afford. Now everyone with a boat and a credit card could put themselves right on the reef (and the fish). A feat that once required a professional fisherman with local knowledge. GPS was a MAJOR leap in technology for the novice fisherman.

GPS didn't become effective until May 1, 2000, when President Clinton turned off GPS Selective Availability, making a GPS accurate to a few feet, from the pre shut off 300 feet. You're right though, GPS did aid in putting fishermen over the same reef with great accuracy, causing a decline in reproductive size reef fish. The problem I see is the lionfish filling this niche. If juveniles of these fish species are consumed at greater rates by an ever growing population of lionfish, while fishermen consume an ever growing number of the reproductive size fish, common sense dictates that sooner, rather than later, these species become endangered, at best.