Population traits of the invasive Trachemys scripta elegans (Reptilia: Testudines: Emydidae) (WiedNeuwied 1838) at Mallorca, Balearic Islands, Spain

EnglishThe importation of the red-eared slider (Trachemys scripta elegans) to Europe for the pet trade has caused frequent release of this alien turtle to the natural environment. Because of these actions, this alien turtle is currently present in wetlands of many countries worldwide. The reproduction of T. s. elegans has been cited in several localities of Mediterranean countries including our study area, s'Albufera de Mallorca (Muro, Spain). During the study 116 individuals were captured; 27 males, 46 females and 43 juveniles. This population was mostly composed of adults, with a statistically significant sexual dimorphism in body size and a female biased sex-ratio. The smallest reproductive female was 172,0 mm of straight carapace length (SCL), and no correlation was found between clutch size and female body length. The 88.9% of sexually mature females were reproductive females and 7.5% of these reproductive females had calcified eggs in their oviducts. The demographic and reproductive parameters analyzed showed a great capacity of colonization and reproduction of the red-eared slider in s’Albufera de Mallorca. The results obtained show the need to propose policies to eradicate the introduced populations of T. s. elegans, as well as to promote the sensitivity of the owners to avoid pet releases to the natural environment. catalaLa importacio de la tortuga de Florida (Trachemys scripta elegans) a Europa com a animal de companyia ha causat una alliberacio frequent d’aquesta especie al·loctona de tortuga al medi natural. Com a consequencia, aquesta especie de tortuga es troba present a zones humides de la majoria dels paisos d’arreu del mon. La reproduccion de T. s. elegans ha estat reportada a diferents localitats dels paisos mediterranis, incloent la zona d’estudi, s’Albufera de Mallorca (Muro, Espanya). Al llarg de l’estudi 116 individus foren capturats; 27 mascles, 46 femelles i 43 juvenils. Aquesta poblacio estava composta majoritariament per adults, amb un dimorfisme sexual estadisticament significatiu en la mida corporal, i una proporcio de sexes enviaxada cap a les femelles. La femella reproductora mes petita tenia 172,0 mm de longitud recta de la closca (SCL) i no es va trobar un correlacio entre la mida de la posta i la longitud corporal. El 88.9% de les femelles eren sexualment madures i el 7.5 % d’aquestes tenia ous calcificats als seus oviductes. Els parametres demografics i reproductius analitzats mostren una gran capacitat de colonitzacio i reproduccio de la tortuga de Florida a s’Albufera de Mallorca. Els resultats obtinguts mostren la necessitat de proposar politiques per a eradicar les poblacions introduides de T. s. elegans elegans, aixi com promoure la conciencia dels propietaris d’evitar l’alliberacio d’animals de companyia al medi natural.