An unresolved problem in aquaculture ponds is the susceptibility of freshwater fish to parasitic diseases, caused by trematodes, which are transmitted by freshwater snails. Unfortunately, these snails are very common in aquaculture ponds evident by more than 150 scientific articles since 2020 that were published on fish infections by Centrocestus alone, around the globe. At least four species of such snails are common in freshwater aquaculture ponds in Israel: the local and over-abundant Melanoides tuberculata, and the invasive Thiara scabra, Tarebia granifera and Pseudosuccinea columella, All being hosts of various disease-causing parasitic trematodes. Since 2017 an ongoing field study in fish ponds, accompanied by laboratory experiments, present a promising future for this biocontrol technology
The giant freshwater prawn, Macrobrachium rosenbergii, a proven voracious predator of freshwater snails - when stocked in polyculture with fish, reduced snail abundances (Fig. 1) and the accompanied parasitic load among fish. Consequently, the demand for M. rosenbergii PLs among fish farmers in the region has been rising (Fig. 2).
Prawns in contrast to fish, occupy a benthic niche in the aquaculture pond and may thus be expected to prey on disease-carrying snails, which burrow into the pond bottoms. Prawns also bring the added advantage of constituting a high-value side-product to the pond-produced biomass without the need for additional feed. Following recent biotechnological advances in monosex prawn production, non-reproducing monosex prawn populations are now commercially available as non-invasive, ecologically safe biocontrol agents in aquaculture.
The effectiveness of this biocontrol agents for Tilapia aquaculture in terms of reduction in both snail abundance and rates of fish infection with the snail-borne parasites.
We suggest a novel sustainable biocontrol concept that presents a win-win-win situation rewarding both Farmers-Fish & the Environment.