Roombaguy
Contributor
In todays Cayman Compass
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Groupers help cull lionfish
Since venomous lionfish began invading Caymans reefs back in early 2008, divers have seemed to be the only line of defence against them, but groupers are now joining the fight.
On Little Cayman, dive masters have begun feeding lionfish to groupers and hope the large fish will teach other groupers to do the same.
It started with the divers feeding dead lionfish to the tame Nassau groupers that interact with divers at Bloody Bay Wall, explained dive master Ron Thompson at Little Cayman Beach Resorts Reef Divers.
In the beginning, we fed our friendly groupers, mainly Benji and Mini-Me, the dead lionfish that we had previously caught and killed. The instructors would... take the nets down with the dead lionfish and open the bags up when the groupers came to see us.
Once they got used to the idea of dead lionfish, we then progressed to live lionfish from the nets, Mr. Thompson said.
Even more recently, they have started to take live lionfish from the reefs if the dive masters point them out, he said.
He explained that prior to trying to teach groupers that lionfish were a tasty snack, the dive masters had never fed the groupers anything.
Groupers have a nuclear hunting behaviour with other creatures, such as moray eels. They hunt together. The groupers use us as hunting partners as we used to point squirrelfish out to them to hunt, he said.
However, despite the fact that the groupers are eating lionfish pointed out by divers, it is not known if they are taking the spiny, poisonous lionfish of their own accord, without divers pointing to them, but Mr. Thompson said he believed it was quite likely.
Groupers are quick to learn and often mimic the behaviours of other groupers, he said.
The Marine Conservation Law was amended following the arrival of the invasive lionfish in Cayman to allow divers to hunt and remove them from the reefs. Lionfish have voracious appetites and can wipe out juvenile and small fish species on a reef in just weeks.
Department of Environment staff say it is vital to control the lionfish population because the fish can lay 30,000 eggs in one spawn and they can spawn every month. The department has been running a series of seminars to educate people about lionfish and certify divers to catch them.
The courses teach divers how to locate and capture lionfish in clear, plastic nets without getting stung, and what to do if they are stung.
And even though lionfish stings are extremely toxic to humans, the groupers do not seem to suffer any ill effects from ingesting the fish. If fact, the Nassau groupers now get very excited if they see the dive masters coming with a net with their new tasty treat, said Mr. Thompson.
Dive masters on Little Cayman have also been feeding dead lionfish to other marine species, including green, spotted and viper morays, octopi, lobsters and reef sharks.
While we do try and catch as many lionfish as we can, we are trying to promote the groupers and other marine life to hunt them as well. It may take time but we are trying to find a natural solution to this problem, Mr. Thompson said.
Mark Hixon, a marine biologist at Oregon State University, who has visited Little Cayman twice this year to study the impact of the lionfish, said he hoped the groupers would teach each others by example to consume the invaders.
But he said that, for now, divers culling lionfish is the best means of keeping their numbers down.
Culling is very effective over small areas, but complete eradication is unlikely unless natural controls - predators, competitors, parasites, diseases - kick in, he said.
cayCompass.com :: Groupers help cull lionfish
=======================
Groupers help cull lionfish
Since venomous lionfish began invading Caymans reefs back in early 2008, divers have seemed to be the only line of defence against them, but groupers are now joining the fight.
On Little Cayman, dive masters have begun feeding lionfish to groupers and hope the large fish will teach other groupers to do the same.
It started with the divers feeding dead lionfish to the tame Nassau groupers that interact with divers at Bloody Bay Wall, explained dive master Ron Thompson at Little Cayman Beach Resorts Reef Divers.
In the beginning, we fed our friendly groupers, mainly Benji and Mini-Me, the dead lionfish that we had previously caught and killed. The instructors would... take the nets down with the dead lionfish and open the bags up when the groupers came to see us.
Once they got used to the idea of dead lionfish, we then progressed to live lionfish from the nets, Mr. Thompson said.
Even more recently, they have started to take live lionfish from the reefs if the dive masters point them out, he said.
He explained that prior to trying to teach groupers that lionfish were a tasty snack, the dive masters had never fed the groupers anything.
Groupers have a nuclear hunting behaviour with other creatures, such as moray eels. They hunt together. The groupers use us as hunting partners as we used to point squirrelfish out to them to hunt, he said.
However, despite the fact that the groupers are eating lionfish pointed out by divers, it is not known if they are taking the spiny, poisonous lionfish of their own accord, without divers pointing to them, but Mr. Thompson said he believed it was quite likely.
Groupers are quick to learn and often mimic the behaviours of other groupers, he said.
The Marine Conservation Law was amended following the arrival of the invasive lionfish in Cayman to allow divers to hunt and remove them from the reefs. Lionfish have voracious appetites and can wipe out juvenile and small fish species on a reef in just weeks.
Department of Environment staff say it is vital to control the lionfish population because the fish can lay 30,000 eggs in one spawn and they can spawn every month. The department has been running a series of seminars to educate people about lionfish and certify divers to catch them.
The courses teach divers how to locate and capture lionfish in clear, plastic nets without getting stung, and what to do if they are stung.
And even though lionfish stings are extremely toxic to humans, the groupers do not seem to suffer any ill effects from ingesting the fish. If fact, the Nassau groupers now get very excited if they see the dive masters coming with a net with their new tasty treat, said Mr. Thompson.
Dive masters on Little Cayman have also been feeding dead lionfish to other marine species, including green, spotted and viper morays, octopi, lobsters and reef sharks.
While we do try and catch as many lionfish as we can, we are trying to promote the groupers and other marine life to hunt them as well. It may take time but we are trying to find a natural solution to this problem, Mr. Thompson said.
Mark Hixon, a marine biologist at Oregon State University, who has visited Little Cayman twice this year to study the impact of the lionfish, said he hoped the groupers would teach each others by example to consume the invaders.
But he said that, for now, divers culling lionfish is the best means of keeping their numbers down.
Culling is very effective over small areas, but complete eradication is unlikely unless natural controls - predators, competitors, parasites, diseases - kick in, he said.
cayCompass.com :: Groupers help cull lionfish
