Susceptibility of Transgenic and Wildtype Zebra Danios, Danio rerio, to Predation

The effects to ecosystems by genetically modified organisms are still unknown, yet a transgenic version (the red glofish or red fluorescent protein (RFP) transgenic zebra danio) of the zebra danio, Danio rerio, a common aquarium fish, has become the first transgenic pet sold in the USA. It has been hypothesized that RFP zebra danios will not persist in nature because they will be preferentially preyed upon due to their red coloration; however, the bright coloration of wildtype zebra danios may indicate they are aposematic since they are not preyed upon immediately by predators in their native range. These hypotheses were addressed via nine predation experiments with largemouth bass, Micropterus salmoides, as predator and combinations of mosquitofish, Gambusia affinis, wildtype zebra danios, and RFP zebra danios as prey. Neither wildtype nor RFP transgenic zebra danios are aposematic since both varieties were readily consumed by largemouth bass in laboratory trials. Both varieties were preyed upon in approximately equal proportion (1.4 to 1.0) so the bright, apparently conspicuous coloration of the transgenic zebra danios did not increase their susceptibility to predation. In these laboratory trials, largemouth bass did not preferentially prey upon a native fish, the mosquitofish, relative to wildtype zebra danios (1.2 to 1.0). Based on the results of these experiments, wildtype zebra danios and RFP transgenic zebra danios are likely to be preyed upon in a similar fashion as native forage fish.