Dive pros join lionfish battle

Selected trained scuba divers are being allowed capture and kill invasive lionfish.

The Department of Environment and the Marine Conservation Board are issuing to those deemed necessary to stem the spread of the red lionfish on Cayman’s reefs, with divers selected on the basis of how much time they spend out on the water. This means that most of the divers licensed to capture red lionfish are dive industry professionals.

lionfish

Lad Akins, Bradley Johnson and Stephanie Green all spoke on a presentation on the red lionfish recently.
Photo: Eugene Bonthuys

The permits grant exclusions to certain sections of the Marine Conservation Law. It allows the permit holder to take lionfish from the reef while using scuba gear and wearing gloves while doing so, both of which are outlawed under the law.

According to Bradley Johnson, research officer with the DoE, this was deemed necessary because of the difficulty of following up on reported sightings of lionfish.

‘Once a report comes in, we have to go out and find a specific rock, next to a specific sea fan, which is very difficult,’ said Mr. Johnson.

He, along with Lad Akins, director of special projects for the Reef Environmental Education Foundation and Stephanie Green of Simon Fraser University recently gave a special presentation on the red lionfish.

‘We really don’t have anything against lionfish, Mr. Akins said. ‘They are beautiful, wonderful fish, but they don’t belong here.’

According to Mr. Akins, divers often raise the question of why the lionfish cannot be allowed to settle on the reef, as it would save divers in the Caribbean the effort of travelling to the fish’s native range to see it.

‘Why don’t we just let it become part of the system?’ Mr. Akins asked. ‘Lionfish are voracious, gluttonous predators and they have the capacity to do severe damage to our native ecosystem through what they are eating.’

The red lionfish also has 13 venomous spikes along its dorsal fin, as well as one in each pelvic fin and three in the anal fin. The sting is agonisingly painful, even though it is not usually fatal.

‘They may look beautiful and fragile, but this is not something you want to touch,’ said Mr. Akins. ‘These lionfish are extremely bold and there have been cases of people being stung in unprovoked encounters with lionfish. They either didn’t know the fish was there or they were minding their own business and the lionfish came out and actively stung the individual. Lionfish are not shy; they are not necessarily going to retreat when you approach.’

Because of the fish’s ambush predator nature, it likes overhang environments where it will often tuck up on the vertical face or even upside down.

‘In all of our talks with dive masters, we really focus on this, because typically divers who really enjoy going into wrecks and swimming through caverns are not looking up. In areas where lionfish are starting to appear, we really need to start focussing on what is above us, because you certainly would not want a lionfish above you with the spines pointing down as you swam through one of those environments,’ said Akins.

Divers hoping to spot one of these fish are more likely to see them during their feeding periods.

‘What we’re seeing is that lionfish are primarily feeding early in the morning, and then around late morning mid-afternoon they tend to shelter, and then they are out on the reef again around sundown for a second round of feeding,’ said Ms Green.

Eliminating the red lionfish from the reef is also a very complex task. Initial attempts both locally and in the Bahamas relied in using spear guns to capture the fish. According to Mr. Akins, the success rate with this method was around 50 per cent.

‘Once we shot at a fish and missed, it knew what was going on – it is not a stupid fish. It would retreat into the coral crevices and holes and we would not get a second chance. And the next time we came back, when that fish saw as coming it knew and it would disappear before we had a chance to get close,’ said Mr. Akins.

The lightning fast reaction of the lionfish also makes it a very difficult prey.

‘We have shot at one from six inches away and missed – they are that quick,’ said Mr. Johnson.

Conversely, the best method to capture the fish is by slowly herding it into a net. Once the team in the Bahamas started following that method, the success rate in capturing lionfish went up to around 95 per cent.

This left the problem of how to dispose of these fish humanely. The solution was to use Eugenol, or clove oil, dissolved in alcohol. Added to the water in which the lionfish is held, this acts as a narcotic on the fish.

‘I have been told that if you’re a lionfish, this is a pretty good way to go,’ joked Mr. Akins.

As the eggs of these fish can spread in the currents, it is unlikely that Cayman will ever be able to eliminate the red lionfish completely, as it is likely that its presence in the surrounding waters will always allow it to reappear on Cayman’s reefs.

However, Mr. Johnson hopes that with proper management the fish can be prevented from settling on Cayman’s reefs and doing irreparable damage to the biodiversity of Cayman’s reefs, and thereby to the Islands’ tourism offering.

0
0

NO COMMENTS