The scale of Cayman’s green iguana problem is now so large it will require a significant investment of time and money just to maintain the population at current levels, environment officials have warned.
The latest population survey shows that the number of iguanas has almost doubled in the past year.
The estimated population size is now 404,000 adult green iguanas.
When hatchlings are included in the count, the number increases to more than 800,000, according to results from the latest islandwide survey, carried out in August.
The Department of Environment now warns the problem is too big for it to manage. After test culls earlier this year, the department is working on a long-term strategy to curtail the exponentially growing population.
But it warns that the funding allocated is nowhere near enough to deal with the issue, and its next step must be to convince government to fund a multiyear population control program.
“The scale of the problem is now so large that it will require a considerable investment of time, resources, equipment and money, and the Department of Environment is not currently resourced to undertake this role,” said Jane Haakonsson of the department’s terrestrial resources unit.
The latest population surveys show not only an increase in numbers, but also a rise in the rate of population growth.
Between 2014 and 2015, the iguana population grew by 60 percent. Between 2015 and 2016, it grew by 98 percent.
Ms. Haakonsson said keeping the population at current levels would be a challenge.
“This will require an intense and very large effort. We know what was involved to remove 19,000 iguanas, and we need to aim to remove 350,000 or more each year just to keep the population stable,” she said.
She said it is unlikely that all iguanas will be eradicated, which means that culling would need to continue over several years.
No specific program has been proposed at this stage, but the Department of Environment expects to make recommendations in the new year through the National Conservation Council.
“It is clear this will likely require a dedicated team of trained individuals working to [a] multiyear plan,” said Ms. Haakonsson. “At the moment, we would aim to simply ‘maintain’ the green iguana population at its current level and only take out annual growth. Even this will be a difficult task and extremely costly and will require a much higher level of funding than previously requested.”
Until then, the department will focus its resources on Cayman Brac and Little Cayman, where the green iguana invasion is in its infancy.
“We are likely to concentrate on biosecurity on the Sister Islands to prevent the green iguanas from getting to the scale of problem they are here,” she said. “It is not too late for the Sister Islands, but it is critical to act now.”