Changes in diet, growth and survivorship of the native Tequila Splitfin Zoogoneticus tequila in co-occurrence with the non-native Shortfin Molly Poecilia mexicana
Escalera-Vázquez, Luis H.; Domínguez-Domínguez, Omar; Hinojosa-Garro, Demián; Zambrano, Luis
published: Oct 1, 2016
published online: Sep 1, 2016
manuscript accepted: Aug 5, 2016
manuscript received: Apr 27, 2016
ArtNo. ESP141018804006, Price: 29.00 €
Abstract In this study, captive-bred fishes were used in a mesocosm experiment in which the native Tequila Splitfin Zoogoneticus tequila and non-native Shortfin Molly Poecilia mexicana were held singly and jointly in different experimental tanks to assess changes in growth and diet composition between the two species. We also examined changes in growth and survivorship at various food abundances during co-occurrence. Experiments were performed at ≈ 25 °C in aquarium and ≈ 20 °C in ponds. In the single-species treatment, Z. tequila exhibited a more diverse diet composition, and P. mexicana exhibited higher survivorship at the lowest prey density. The non-native Poecilia had no effect on growth of the native species; this could be related to the possible elimination of smaller individuals of the native species in treatments with low chironomid densities. The Shortfin Molly also exhibited higher survivorship at low food availability in co-occurrence and single species treatment. These findings contribute to a better understanding of native species responses to non-native species. The experiments illustrate possible mechanisms by which non-native fish affect native species in freshwater environments where the effects of small non-native fish species have not been considered fully.