Aquatic Invasive Species: Traditional Control Options to Emerging Genetic Bio-control Strategies

Abstract

Worldwide, alien species invasion already constitutes to be a major threat to the biodiversity of various ecosystems, particularly in freshwater ecosystems, and with a warming of the climate, the range of habitats suitable for its establishment may increase further. Though it is possible to manage invasive aquatic species in small invaded areas by physical removal, use of barriers or biocides, and environmental modifications, once established and widely distributed, the eradication of invasive species often becomes impractical. To date, biological control is considered the prime realistic option for controlling well established and widely distributed invasive species. But the application of classical biological control methods using unmodified living organisms (predator, parasite or pathogen) to control target populations of alien fishes is very limited to date, mainly because of the difficulties in finding suitable agents. Recent advances in genetic technologies, like chromosome set manipulations or recombinant DNA techniques, or a combination of both techniques provide opportunities that could be used for the control and eradication of individual invasive species. Approaches like sterile-male, super male, female lethal, bisex-lethal, trojan female, sex-reversed trojan female, neo female, daughterless technology, and CRISPR/CAS9 – gene editing are considered far more species-specific than mechanical or chemical methods, and also efficient and cost-effective. However, just a few trials of some of these methods have been undertaken in the field to date, and hence there is still a long way to go before tuning genetic biocontrol approaches into an on-field reality.