Whilst this story is about a green moray eel named Curious George, to begin I need to first discuss lionfish; specifically, what they are and how they have become an invasive species in certain parts of the world.
Lionfish are a carnivorous fish which are native to the Indo-Pacific, however in the Caribbean they have been an invasive species since the early 1990's, reaching The Bay Islands in 2008 where they have posed a threat to reef ecology. Due to their speedy growth rate and population numbers, they have spread across oceans incredibly fast. How their species became a problem is not exactly known, but it is thought that an aquarium owner released their pet lionfish into the wild which is how it all began.
[Lionfish dissections at the 2017 Derby]
Before I get into storytelling mode, here's just some of the crazy facts you may like to know about Lionfish:
- A sexually mature female (1 year of age) can reproduce every 3-4 days!
- They can lay up to 30,000 eggs each time.
- In their native oceans, it is thought that lionfish live up to 10 years, but have survived for up to 35 years in captivity. In oceans where they are invasive, lionfish could live much longer than 10 years due to having no natural predators.
- Lionfish have venomous spines, 13 on their dorsal fin, 3 on their anal fin and 1 on each of their pectoral fins.
- There have been no known documented human fatalities from a lionfish sting, though people who are also allergic to bee stings could have a much more severe reaction.
- Lionfish are safe to eat (and encouraged in the Caribbean!). They are a white, flakey meat with a higher concentration of Omega 3 and less Omega 6 fatty acids, meaning it is also a very healthy fish to eat.
- Lionfish can survive a variety of conditions and have even been found in New York's cold waters as deep as 1,000ft. They can also survive in freshwater.
- They eat anything that they can fit in their mouth!
- Their stomach can expand up to 30 times its size.
- They have been known to even eat their own species.
- They use a variety of hunting methods, such as blowing jets of water to confuse their prey before swallowing them.
- They eat a lot of economically important fish, and therefore pose a threat to the livelihood of fishermen.
- They live on coral reefs and mangroves where they eat a lot of juvenile fish.
- Lionfish are contributing to the phase shift from a coral dominated reef to an algae dominated reef by eating important grazers: parrotfish who remove algae off the reef.
- They also eat cleaner fish which are important to the health of other species.
I could go on and on, but basically, they are a huge problem in their non-native waters and are a severe threat to the livelihood of our reefs as well as those who depend on it being healthy in order to survive.
[Guess which hand was subject to a lionfish sitng?]
Utila is one of the many affected locations in the Caribbean where lionfish removal projects have been implemented by dive shops and conservation centres across the island. Every month, the Whale Shark & Oceanic Research Centre (@wsorc_life) joined with the Bay Islands College of Diving (@diveutila) to train their marine conservation and Divemaster interns how to safely and responsibly use Hawaiian sling spears, practicing on onions and potatoes before heading out on removal dives. Divers are trained to hold a container called a 'zookeeper' which has a one-way funnel system to keep the fish inside once they've been speared. WSORC then keep the fish for their dissection workshops, in which staff and interns collect data pertaining to each individual's size, sex, stage of development, stomach content and the fillets are kept for consumption - nothing goes to waste!
[Lionfish dissections with WSORC]
Divers on Utila regularly patrol the islands' fringing reef where boats moor up to daily. You can still see lionfish at these dive sites, but due to recreational divers taking spears on their fun dives, their numbers are somewhat controlled. However, further out from the coast is a different story. There are countless sea mounds surrounding the island which don't receive as much traffic from dive shops, therefore lionfish numbers are far greater in these areas.
So what has all of this background info got to do with a moray eel named Curious George?
Well, one of the controversial issues when dealing with an invasive species is the various different methods used to control their ever-growing numbers. I'm talking about introducing an invasive species to local predators in hope of them recognising that new species as prey, and in time will also learn to hunt. Problem solved! Oh no....
[A successful removal snorkel in Belize]
In their native habitat, lionfish have many natural predators such as moray eels, sharks, groupers, scorpionfish and frogfish. These species have eaten lionfish for thousands of years and recognise them as prey, which cannot be said for the same predatory species in the Caribbean. Differing from other animals, fish do not teach their young to hunt and habits are not passed down through generations. Therefore it is unlikely for us to train species such as nurse sharks and moray eels to hunt lionfish, and we would have to continue training every new generation.
This hasn't stopped divers giving it a try though! Whether it be as a genuine effort to control invasive numbers, or just a cool party trick to impress their customers, dive guides across the Caribbean have been known to feed lionfish to nurse sharks and moray eels off the end of their spear. As you can imagine, this has negative implications for both humans and the wildlife, and here is where Curious George comes into our story.
[Placing lionfish into the zookeeper during removal dives]
Raggedy Cay is a dive site located off the West coast of Utila, an area with diverse marine life and topography. Ideal for almost any PADI course including Tec diving, and personally memorable for me as this is where my partner saw his first hammerhead shark... and I missed it. For years this dive site was also unique as it was home to a rather large green moray eel, known for approaching divers, hence the name Curious George. As you may know, it is quite extraordinary for a moray eel to approach divers directly, unprovoked. This behaviour was a result of divers feeding lionfish to Curious George over time, resulting in the eel associating divers with food. Though never aggressive, I would be sure to warn my divers about this friendly eel, briefing them to stay calm and wait for Curious George to check us out before leaving us be once he had discovered that we didn't have any food for him.
In that sense, Curious George was harmless, and I looked forward to saying hello to him whenever we dove at Raggedy Cay. Though he was well known across the island, people visiting Utila who may not have been diving with a local guide or shop, would not know about our friend George, and I can understand that seeing a large free-swimming moray eel excitedly approach you would seem threatening. Sadly, one day this exact situation played out and Curious George was killed; I assume with a spear in what the diver intended to be self defence. This is the unfortunate outcome of trying to introduce an invasive species to native predators.
I have also witnessed similar behaviour from Utila's resident nurse sharks a result from being fed by divers. Another popular dive site that we patrol for lionfish, just north of Raggedy Cay, is Spotted Bay. It is clear that the nurse shark who lives here also associates divers with food, and isn't shy to check us out before swimming off. However, if we are removing lionfish during a dive, some nurse sharks can be a bit too friendly and won't leave us alone. If the lionfish is on a spear, you can say goodbye to that fish immediately and the shark will swim off with your meal for himself. If you have dead lionfish in a zookeeper container, it can be trickier to divert the shark's efforts. The last thing we as divers want to do is open up the zookeeper and allow the shark to our lionfish, as we are adding to the problem. In this case, if gently nudging the shark away with your fin or blunt end of the spear doesn't work, then it's best to end the dive. The worst outcome I've heard of in this situation was when one of our long-term divers received what he called a 'love bite' from a nurse shark, in which he was essentially bitten. Nurse sharks have thousands of tiny serrated teeth, so whilst they wouldn't take a fatal 'chunk' out of you, a bite from them will puncture your skin and leave an impressive mark behind!
Based on the sad outcome of Curious George, I hope that Utila's residents nurse sharks don't meet the same fate. When I used to teach the Lionfish Removal workshop at WSORC, I always used this story as an example to highlight the negative impacts from trying to teach a local predators to hunt an invasive species. It does more damage than good, and it's an unrealistic solution to the problem. It's unlikely that we can ever eradicate invasive lionfish as their numbers have spread too far, wide, and deep to completely remove them. However, continuous removal projects are proving to be affective in certain areas which will hopefully continue to take the pressure off of reef health and allow important species to recover.
[One of my first removal dives back in 2016 with WSORC]
As always, thanks for reading and I'd love to hear your thoughts!
Safe diving & happy dreaming,
A.
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