Invasive species represent a threat to biodiversity and cost millions of dollars to the global economy every year. The Mexican live-bearing fish known as Picote de Tequila (Zoogoneticus tequila) is now extinct in the wild as a consequence of habitat reduction and interactions with invasive species. Picote de Tequila is native to Central México. Its former habitat is currently invaded by the Twospot livebearer (Heterandria bimaculata) a species from Central America. Little is known about the social behaviour of this species, although it is believed to be bold and aggressive. Picote de Tequila will be reintroduced in the wild, particularly in the Teuchitlán River. Approximately 80% of the fish found in this river are exotic; over 50% of them are Twospot livebearers. Our aim is to explore how Picote de Tequila will interact with other natives and the invasive Twospot livebearer before actually reintroducing them in the Teuchitlán River. An experiment at the mesocosm level allowed us to assess reintroduced populations maintenance, and demographic changes when sharing habitat with heterospecifics. We also followed focal individuals in each mescocosm and recorded boldness, aggressive interactions and time associating with individuals of different species.
Results/Conclusions
Picote de tequila showed a higher mortality when introduced to mesocosms that held Twospot livebearers. Populations of Picote de Tequila declined faster when sharing habitat with Twospot livebearers. Interestingly, Picote de Tequila did better when sharing habitat with other native fish than when being alone, suggesting they are a social species that benefits from interacting with other species. Our results provide new information to better design the reintroduction of Picote de Tequila and maximise the chances of survival of reintroduced individuals and ultimately re-establish the species. Detailed knowledge of behavioural interactions is essential for sound conservation and management decisions.