It was another pedestrian fishing excursion for this five man fishing contingent on a Saturday morning in December. The day brought azure skies, gentle zephyrs and a placid Caribbean Sea, all typical of the picturesque composition that is Soufriere. The fathomless waters below Petit Piton usually made for good fishing and on this day, these boatmen expected the usual ballyhoo yield.
About 9am, maybe two hours after setting out, the fishers spotted something extraordinary. It was a 2 metre long fish unlike any they’d seen before. It seemed almost . . . reptilian. Urged on by sheer curiosity, the fishermen eagerly pursued this most unusual of sea creatures. The men were almost upon this thing when it suddenly retreated to the depths, but not before nets had been cast in the desperate hope of a capture. Ten meters below, the sea beast was intercepted, ensnared and entangled in nylon mesh. The seamen hauled in their catch and in eye-popping disbelief, the mystical beast was identified. They’d fished an iguana!
Proud and with the hope of a reward of some sort, the captors contacted the Soufriere Marine Management Association (SMMA) about their intriguing quarry. Furthermore, they’d noticed a rather peculiar belt near the base of the lizard’s tail. It had apparently been tagged or marked for research. Fortunately, SMMA staff knew just who to call, and soon personnel of the St. Lucia Forestry Department (SLFD) had collected the seemingly amphibious reptile.
National Geographic channel enthusiasts may wishfully assume that Soufriere must now be home to the world’s second population of marine iguanas, lizards known to remain submerged for a full half hour while feeding. However, these aquatic reptiles remain endemic to the distant isles of the Galapagos and the prized catch of these Soufriere boatmen was an exotic of another variety. Far from being an isolated individual, the large captured lizard was part of an established population of common green iguanas introduced to the island’s south-west.
While animal lovers may welcome the introduction of new wildlife species to our shores in the belief that our biodiversity is being enriched, the converse actually holds true. The introduced green iguana poses a direct threat to our native St. Lucia iguana as hybridization would undoubtedly compromise the gene pool of the latter. The SLFD is the nation’s leading authority on the conservation of terrestrial flora and fauna and as such, the preservation of the indigenous St. Lucia Iguana falls under the department’s mandate. In partnership with Durrell Wildlife Conservation Trust, the SLFD is currently running a campaign to control the spread of these alien iguanas so as to keep the alien population geographically separate from its indigenous counterpart in the island’s north east. This initiative has been funded by Global Environment Facility (GEF) and operates under the auspices of Centre for Agricultural Biosciences International (CABI) and the United Nations Environment Programme (UNEP).
The control or eradication of any invasive alien species population requires an intimate knowledge of its ecology. Baseline population estimates as well as distribution, dispersal and habitat use data can inform eradication efforts and allow often limited resources to be used in the most effective manner. Radio-tracking or radio-telemetry is one method which the SLFD has employed to become familiar with the daily movements and habitat use of alien iguanas in Soufriere.
In Soufriere, some of the captured alien lizards have been fitted with collars and released. Each radio-collar or radio-tag emits a continuous radio signal which can be picked up by a receiver. This allows SLFD researchers to zero in on the locations of tagged lizards.
Such is the battle that the Forestry Department is engaged in against an all but insuperable foe. It must be noted that of the other territories in which introduced green iguanas have become established, including Puerto Rico, Fiji, Florida and Martinique, not one has been successful in thwarting this “green invasion”. The invaders are fecund, adaptable and resilient and amazingly cryptic amongst Soufriere’s verdant vegetation. They are capable terrestrial runners, spend most of their lives at the loftiest of perches and even take to air when frightened, able to fall twenty meters unharmed.
Surprisingly, iguanas can hold their breath underwater for over four hours and frequently use water as an escape route, although sightings at sea are rare.
The deep salt waters of our seas pose little restriction to these reptiles’ movements and as seen above, are adept swimmers and divers. Yet with the knowledge that the future of our St Lucia Iguana hangs in the balance, the SLFD continues on with hopeful determination, fully intending to explore all options and level available resources against this green hoard of invaders.
Through intense and innovative efforts it is the department’s hope that our beloved native iguana, after which the ancient Amerindians so named our land, lives on for future generations.