Estudi i comparació del creixement, la mortalitat i la condició de l’espècia Salvelinus Fontinalis en tres estanys d’alta muntanya del Pirineu

Abstract

SORELLÓ, Estudis al Medi Aquàtic S.L. is a company which is involved in the Life + Limno Pirineus project, that aims to improve the conservation status of aquatic species and habitats of European interest in the high mountain areas of the Pyrenees (CEAB-CSIC, s.d.). One of the objectives of this project is the demographic study of invasive species populations, amongst them the brook trout (Salvelinus fontinalis). Although some demographic work has already been realized, the obtained results seem to be not very reliable, possibly related to the procedure used to determine the age of the trout’s. Therefore, the here presented project is going to focus on the improvement of the methodology used to determine the age of the S. fontinalis by reading the rings of the bony structures called “otoliths” which provide information of the age. Combining the so obtained age with length and weight of the fish will result in adequate data to realize the demographic study. To carry out the study the same samples of the introduced species, already used in previous studies (Dalmau Quera, 2017; Berché Barceló, 2017) will be used. Such samples were captured in the context of the above-mentioned project (Life + Limno Pirineus) during 2016 and 2017 in three high mountain ponds of Pallars Sobirà. Finally the obtained data from the new demographic study will be compared with the corresponding results of previous studies. It is expected that the new technique for determining the age by reading the otolith rings will result in more reliable date regarding the ages of fish. In consequence it will be possible to compare the different demographic studies. It is expected that clear differences will be observed related to growth, mortality and physical condition due to the underestimation of age in the former studies