Invasivores Down Under

This last week I’ve been in Cairns, Australia, in tropical Northern Queensland.  I’ve been searching for a prime invasivore target: Tilapia.  Tilapia mariae and Oreochromis mossambicus where introduced into Australia several decades ago, and started becoming a problem about 20 years ago.  In many areas, these tilapias have come to dominate native fish communities.  Alas, it remains a crime in pest-aware Australia to possess tilapia, dead or alive.

Stop the Spread of tilapia
In the Cattana Wetlands, both T. mariae and O. mossambicus are well established. Catching tilapia is, unfortunately, not allowed.

I’m not here to harvest tilapia, but instead test a new method for detecting them, environmental DNA, also known as “eDNA.”  Using eDNA, it’s possible to detect the presence of invasive species much faster and at much lower densities than is possible using standard methods like nets or electroshocking.  This method has recently been used with much success to detect the spread of Asian Carp up the Mississippi river and approaching the Great Lakes via the Chicago shipping and sanitary canals.

We’re testing this new method to try and better understand the distribution of tilapia in Queensland, and hopefully help target control efforts to prevent this species from establishing in Australia’s grand Murray-Darling Basin and the Gulf of Carpentaria, and evaluate how well previous eradication attempts have succeeded.

I’ve just finished up in Cairns, and now I’m off to Brisbane, another epicenter of the tilapia invasion.

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