Tilapia has quickly risen through the ranks as an important aquaculture fish. It's third in production behind carp and salmon, with over 1.5 million metric tons produced every year. Tilapia are the ideal fish farm species because they're omnivorous, fairly big, quick-growing, tolerate high densities quite well and are mighty tasty. They are also considered far more environmentally friendly than other species because they can be fed a vegetarian diet. A recent study of tilapia in Fiji drew some attention, however.
Tilapia species have been in Fiji since at least 1949, and fish farms there produce tons of it. But there's a downside to being the perfect fish to farm: tilapia are also a highly damaging invasive species. Because they grow fast and eat whatever is available, they're very adaptable to living in just about any freshwater environment that's warm enough. They've invaded the waterways of many of the countries that farm them commercially.
The study revealed that these escapees are damaging the natural biodiversity of Fiji's waterways. Researchers from Wetlands International, the Wildlife Conservation Society, and Conservation International found that two things correlated strongly to the diversity of native fish in an area. First, they found that the more an area had been cleared for housing or other reasons, the fewer species of native fish. That was not shocking. It was the second variable that decimated native fish diversity that made headlines: the presence of tilapia. Of the 89 different sample locations surveyed, 85.4 percent had been invaded by tilapia.
