Kodela Tjaša, Jesenšek Dušan, Sušnik Bajec Simona
Fisheries Research Institute of Slovenia, Spodnje Gameljne 61 a, 1211 Ljubljana-Šmartno, Slovenia.
Zavod Sara Vuri, Prekomorskih brigad 10, 5220 Tolmin, Slovenia.
Anim Reprod Sci. 2023 Feb;249:107196. doi: 10.1016/j.anireprosci.2023.107196. Epub 2023 Jan 17.
European grayling (Thymallus thymallus) is an endangered salmonid fish species and its populations have decreased considerably in European waters in recent decades. One of the conservation measures applied to grayling is stocking with hatchery-reared fish. To advance the knowledge of grayling reproduction in the hatchery, husbandry data were systematically collected in the period from 2006 to 2015 during grayling spawning seasons and analyzed to quantify grayling female reproductive parameters such as fecundity, egg size, and embryo survival to the eyed egg stage. Data was collected for first time spawners (3 years old) and repeat spawners reared in the hatchery. Statistically significant differences were found for the number of eggs between first time spawners, producing on average 3600 eggs, and repeat spawners, producing on average 8000 eggs. Absolute fecundity was positively correlated to grayling female total length and weight for both first time and repeat spawners. However, relative fecundity did not correlate with these parameters. A positive correlation was observed between female total length and mean egg weight for repeat spawners, while the correlation was negative for first time spawners. Heavier eggs tended to have a higher rate of survival until the eyed egg stage, though the correlation was stronger for first time spawners than for repeat spawners. Due to the higher reproductive success of repeat spawners, it could be concluded that larger and older grayling females should be included in hatchery reproduction.
欧洲茴鱼（Thymallus thymallus）是一种濒危的鲑科鱼类，近几十年来其种群数量在欧洲水域大幅减少。对茴鱼采取的保护措施之一是投放人工养殖的鱼苗。为了增进对茴鱼在人工养殖环境中繁殖情况的了解，在2006年至2015年茴鱼繁殖季节系统收集了养殖数据，并进行分析以量化茴鱼雌鱼的繁殖参数，如繁殖力、卵大小以及到眼点期的胚胎存活率。收集了首次产卵的3岁鱼以及人工养殖的重复产卵鱼的数据。首次产卵鱼平均产卵3600枚，重复产卵鱼平均产卵8000枚，两者在产卵数量上存在统计学显著差异。首次产卵鱼和重复产卵鱼的绝对繁殖力均与雌鱼的全长和体重呈正相关。然而，相对繁殖力与这些参数无关。重复产卵鱼的雌鱼全长与平均卵重呈正相关，而首次产卵鱼则呈负相关。较重的卵在眼点期前往往有较高的存活率，不过首次产卵鱼的这种相关性比重复产卵鱼更强。由于重复产卵鱼的繁殖成功率更高，可以得出结论，人工养殖繁殖应纳入体型更大、年龄更大的雌鱼。
