Blue iguanas near milestone number in wild

Cayman’s blue iguana population is healthy and poised to reach a round number milestone in its renaissance from the threat of near-extinction. The Blue Iguana Recovery Programme will release its 1,000th specimen into the wild at some point this summer, accomplishing a rare victory in the field of species conservation.

At the population’s nadir in 2002, the Blue Iguana Recovery Programme estimated that there were only 10-25 blue iguanas left in the wild. The wild population was considered functionally extinct in 2005, but the captive breeding program has yielded success in rejuvenating the species found only on Grand Cayman.

There are currently 170 caged blue iguanas at the Queen Elizabeth II Botanic Park, and they have been undergoing a detailed health analysis over the last few days by a visiting team of international veterinarians. If all goes well, they will start being released into the wild at some point next month.

Fred Burton, the Terrestrial Resources Unit manager for the Department of Environment, said Monday morning that the blue iguana has weathered a two-pronged assault on its recovery. The species has apparently survived a strain of helicobacter bacterial infection that recently caused the death of 14 blue iguanas, and also predation by dogs that have intruded into the Botanic Park.

The latter threat forced the Botanic Park to erect a series of fences that have partially closed the park to the outside world. There are still sections of the fence that need to be completed, but Mr. Burton said Monday morning that authorities are “reasonably confident” the park is now dog-free.

The helicobacter situation is a little more fluid. The source of the bacterial infection has never been pinpointed, and Mr. Burton said the DoE wants to be certain the iguanas are healthy before they are released into the relative safety of the 646-acre expanse of the Salina Reserve.

“We haven’t had any cases now in a couple of years,” he said. “Nonetheless, right before we’re ready to release them, we’re putting 10 into quarantine cages off site and then monitoring them for 10 days. If they’ve got the helicobacter, they’re going to fall sick in that period of time. If they don’t fall sick in that period of time, then they don’t have the helicobacter and we know we’re safe to let them go. The only other way we can tell is by doing a fancy genetic testing that we don’t have the setup to do here.”

The invasive green iguana was long thought to be a source of the helicobacter, but Mr. Burton said that initial testing by Dr. Ioana Popescu of Island Veterinary Services has not confirmed that hypothesis.

The green iguana has been found to carry the helicobacter, but scientific testing of 100 green iguana specimens in and around the Botanic Park has come back negative.

“We’re still trying to figure out where the reservoir was that these animals got infected from,” Mr. Burton said. “It obviously wasn’t originally here, and it’s obvious the blue iguanas are not co-evolved for this pathogen because it’s so toxic to them. It’s obviously a new experience for them altogether. They must’ve got it from something else, and we’re still trying to figure out what. One of our invasive species, almost certainly, but we haven’t been able to find the smoking gun, so to speak.”

The Blue Iguana Recovery Programme now estimates that there are more than 1,000 blue iguanas in the wild, and most of them are in the Salina Reserve. The ones that have been released are microchipped and adorned with colorful beads for identification purposes.

And while the species is thriving in the reserve, it has become a little more rare to see one in the Botanic Park. There are currently only six or seven free-roaming blue iguanas in the park, and the recovery program seeks to release an equal number back into the park in the coming weeks and months.

“We used to have between 35-40 free-roamers here in the park,” said Alberto Estevanovich, warden of the Blue Iguana Recovery Programme and tour group leader at the Botanic Park. “We lost a lot of them killed by wild dogs. And they were big animals, very beautiful animals. We collected the rest of them and put them in captivity until we finish this fence. We’re going to put them back.”

The caged blue iguanas at the reserve must be at least two or three years old before they are released into the wild. They must be not only able to reproduce but also be big and strong enough to defend themselves in territorial squabbles against other blue iguanas or green iguanas that have infiltrated the reserve.

Once they are deemed safe for release, they will be taken in groups of 10 and given a chance to thrive on their own in the wild. For the Blue Iguana Recovery Programme, it’s a matter of delicate timing, because the effects of captivity on the species can have an adverse effect on their chances to survive in the wild.

“Keeping iguanas in captivity is not good for their health,” said Stuart Mailer, environmental programs manager for the National Trust. “It’s a trade-off. We can’t guarantee 100-percent safety to [the] animals, but they’re not 100-percent safe in the pens because it deteriorates their health.”

Support local journalism. Subscribe to the all-access pass for the Cayman Compass.

Subscribe now