Wed | Dec 12, 2018

Predatory fish wiping out mangroves

Published:Saturday | January 16, 2016 | 12:00 AM


I think that the Government of Jamaica, through the Ministry of Agriculture's Fisheries Division, was unwittingly complicit in introducing one of the world's most invasive species of fish in Jamaican waters.

During the time that I farmed tilapia in Jamaica, we used the grass carp (Ctenopharyngodon idella), a herbivorous fish that fed ferociously on the roots of plants, to keep the fish ponds clear of water grass. It was through technology transfer from our counterparts in Israel that we learned how to inexpensively and effectively control this nuisance of grass overgrowing our ponds. The grass carp was bred by the Fisheries Division and sold to us farmers.

This freshwater fish is a native of Asia and I am now learning that they are very territorial. They have been discovered in the Great Lakes and there is currently an effort in North America to contain and curtail their existence in the lakes.

Why should we be concerned? It has now been discovered that this fish will easily switch from plant to plant to feed, and because of its ferocious appetite, it will even feed on the roots of mangroves if soft grass is not available.

I wonder how many of these fish we might have released into our rivers when we flooded our ponds and what might they be doing to our natural fish habitat and mangroves. Probably a study should be commissioned to measure the effect of the existence of these fish in out waters.


Ontario, Canada