Persistent Unequal Sex Ratio in a Population of Grayling (Salmonidae) and Possible Role of Temperature Increase

摘要: In some fishes, water chemistry or temperature affects sex determination creates sex-specific selection pressures. The resulting population ratios are hard to predict from laboratory studies if the environmental triggers interact with other factors, whereas in field studies, singular observations of unusual may be particularly prone selective reporting. Long-term monitoring largely avoids these problems. We studied a grayling (Thymallus thymallus) Lake Thun, Switzerland, that has been monitored since 1948. Samples spawning fish have caught about 3 times/week around season, and at site continuously recorded 1970. used scale samples collected different years determine average age spawners (for life-stage specific analyses) identify cohort born 2003 (an extraordinarily warm year). Recent tissue were genotyped on microsatellite markers test for genetic bottlenecks past estimate genetically effective size (N(e) ). Operational changed approximately 65% males before 1993 85% 2011. Sex correlated temperatures experienced their first year life. best explained by juvenile during summer. Grayling abundance is declining, but we found no evidence strong bottleneck would explain apparent lack evolutionary response unequal ratio. Results show endocrine disruptors study area. Our findings suggest ratio thereby contributes decline. Persistencia de Proporcion Sexos Desigual en una Poblacion Timalos (Salmonidae) y el Posible Papel del Incremento la Temperatura.