Fiji Times Logo

Fiji Time: 6:20 AM on Sunday 20 April

/ Front page / News

Tilapia's invasive nature

Monday, January 18, 2010

TILAPIA -- a fast-growing, highly palatable, fish native to Africa -- has become a favourite among sustainability-minded diners.

Indeed, when sourced from US farms, the Monte-rey Bay Aquarium gives it a "best choice" rating.

But tilapia's hardiness, versatility, ability to grow quickly with little protein -- the very things that make it so successful in aquaculture -- mean that it is a dangerous invasive species when allowed to move into new ecosystems.

The newest region to struggle with tilapia's insidious durability is Fiji.

There, researchers have found a marked decline in the presence of native fish species. Particularly affected are various species of goby -- a fish that matures in freshwater streams before moving into a saltwater habitat.

Researchers believe that the tilapia, now thriving in the rivers of some islands, eat the larvae and juvenile fish of the gobies before they have a chance to migrate from the streams.

A survey found that streams with tilapia contained 11 fewer native species on average than those without.

Dr Caleb McClennen, director of the Wildlife Conservation Society's Marine Program which led the study, explained that "protecting marine and aquatic biodiversity takes more than managing isolated rivers or coral reefs."

"A holistic conservation approach is needed, one that incorporates freshwater systems, the surrounding forest cover, coastal estuaries and seaward coral reefs," he said.

"As aquaculture continues to develop worldwide, best practices must include precautionary measures to keep farmed species out of the surrounding natural environment."