Invasive alien species (IAS), also called invasive exotics, generally refer to introduced species (non-native species) that adversely affect the habitats and bio-regions they invade. These effects may be economic, environmental, and/or ecological. Such IAS may be either plants or animals, and may disrupt by dominating a region or habitat from loss of natural controls, such as predators or herbivores.
The EPPD was fortunate to host Ms Fadilah Ali, one of the Caribbean’s leading researchers on lionfish, on December 12th, 2012 for an awareness session on the lionfish, an IAS which may soon threaten our local reef ecosystems. The lionfish (Pterois volitans) is a voracious predator, originating from the Indo-Pacific region, and are believed to have been introduced via intentional and/or unintentional releases from aquaria.
Ms Ali, a T&T native, is currently a PhD candidate at the University of Southampton, UK and has done much of her fieldwork on the island of Bonaire. She gave an enlightening exposure on the ecology of the lionfish and its potential impacts on coral reefs around Tobago, where the presence of lionfish was confirmed earlier this year.
|Ms Fadilah Ali educating youngsters on the features of the lionfish|
Lionfish are deemed as one of the most invasive species of all time due to:
- High reproductive rate and ease of dispersal: Lionfish can lay up to 10,000 eggs, three times a month. To make matters worse, their eggs form a mucous-bound gelatinous mass which are easily dispersed by ocean currents.
- High growth rate and density: When they invade an area or range, lionfish tend to have higher growth rates and densities as compared to their native range. They also have higher growth rates than the native fish.
- High feeding rate and generalist diet: Lionfish feed primarily on small teleost fishes and invertebrates, such as shrimps and crabs, through a wide variety of feeding strategies. They can also stretch their stomachs to 30 times the original size, allowing them to feed on prey up to two-thirds their size. Lionfish can go without food for up to 12 weeks, but in their invaded range, due to the abundance of prey items, they feed at least twice daily. Unlucky for us, lionfish feed on our commercially important species such as snappers and groupers, and on herbivorous fish which keep algal growth in check on our coral reefs.
- No natural predators: Many of the native predators in the Caribbean do not recognise lionfish as potential prey due to their unique red-brown colouration, and also because of their powerful venomous spines.
- Venomous spines: Lionfish possess venomous dorsal, ventral and anal spines. This venom is a neurotoxin which is protein based which means that once heat is applied, the venom is destroyed. Thus, if stung by a lionfish, apply heat to the affected area, and seek medical attention.