ABSTRACT

The relationship between water temperature and gonadal maturation of a landlocked ecophenotype of marine pejerrey (Odontesthes argentinensis) in La Salada de Pedro Luro lake was analysed during three spawning seasons. Mainly vitellogenic females were found in August (winter), some ovulating in October (mid-spring) and with atretic oocytes in December (end of spring). In accordance with this, gonadosomatic index (GSI) and estradiol plasma levels showed maximum values in October (7.6 ± 0.7%; 1631.7 ± 256.1 pg/mL) and minimum values in December (1.2 ± 0.3%; 230,33 ± 8,74 pg/mL). Spermiating males were found during the whole spawning season and only arrested in December. The highest GSI values were recorded in October (4.6 ± 0.2%) and for testosterone (T) in August (1113.2 ± 503.8 pg/mL). Meanwhile, in December the minimum GSI and T plasma values (1.3 ± 0.6%, 323.8 ± 5.3 pg/mL) were observed. According to the Fourier fitted models, temperature explains more than 70% of the observed variation in GSI in both sexes. Moreover, the total GSI variation range was positively related to the total temperature range variation experienced during the reproductive seasons demonstrating the influence of this environmental variable on maturation intensity and dynamics.

摘要

一种内陆生态表型的海洋佩杰雷（Odontesthes argentinensis ）的水温与性腺成熟的关系) 在三个产卵季节对 La Salada de Pedro Luro 湖进行了分析。主要在 8 月（冬季）发现卵母细胞，一些在 10 月（春季中期）排卵，在 12 月（春末）发现卵母细胞闭锁。据此，性腺体指数 (GSI) 和血浆雌二醇水平在 10 月份出现最大值（7.6 ± 0.7%；1631.7 ± 256.1 pg/mL），在 12 月份出现最小值（1.2 ± 0.3%；230.33 ± 8.74）皮克/毫升）。在整个产卵季节都发现了有精子的雄性，直到 12 月才被捕。最高 GSI 值记录在 10 月 (4.6 ± 0.2%) 和睾酮 (T) 在 8 月 (1113.2 ± 503.8 pg/mL)。同时，在 12 月观察到最低 GSI 和 T 血浆值 (1.3 ± 0.6%, 323.8 ± 5.3 pg/mL)。根据傅里叶拟合模型，温度解释了超过 70% 的观察到的 GSI 在两性中的变化。此外，总 GSI 变化范围与生殖季节经历的总温度范围变化呈正相关，表明该环境变量对成熟强度和动态的影响。