The effects of water temperature during the non-spawning season (yolkless to early yolk formation stage of the ovary) on the growth and reproductive characteristics of 4-year-old hatchery-reared walleye pollock Gadus chalcogrammus (repeat spawners) were examined. Fish were kept in tanks under two temperature regimes (non-controlled: 6.4–17.2 °C; cooled: 5.1–15.7 °C) from 42 to 46 months post-hatching (non-spawning period) and showed differences in growth (in terms of weight and condition factor) shortly before the spawning period (mostly at the early yolk formation stage of the ovary). The fish spawned spontaneously from 47 to 51 months post-hatching at 5 °C. Growth differences were related to egg diameter but not to the timing of spawning. Larger eggs were spawned from fish that had greater increases in weight and condition during the non-spawning season. In contrast, the main spawning period did not vary according to the non-spawning season treatment. These results were compared with the spawning records of 2- and 3-year-old walleye pollock from two previous years, showing that the timing of spawning advances as fish size increases with age. In addition, spawning experience and the amount of energy acquired before the spawning period likely influence egg size.

中文翻译：

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非产卵季节（无卵黄至卵黄早期形成阶段）温度对孵化场饲养、重复产卵的白斑狭鳕Gadus chalcogrammus生长和繁殖特性的影响

研究了非产卵季节（子房从无卵黄到卵黄形成早期）水温对 4 岁孵化场饲养的白斑鳕鱼（重复产卵者）生长和繁殖特性的影响。鱼在孵化后 42 至 46 个月（非产卵期）在两种温度条件下（非控制：6.4-17.2°C；冷却：5.1-15.7°C）保持在水箱中，并显示出生长差异体重和条件因素）在产卵期前不久（主要是在卵巢的早期卵黄形成阶段）。鱼在孵化后 47 至 51 个月在 5°C 下自发产卵。生长差异与卵直径有关，但与产卵时间无关。在非产卵季节，较大的卵是从体重和状况增加较大的鱼中产卵的。相比之下，主要产卵期没有根据非产卵期处理而变化。将这些结果与前两年的 2 岁和 3 岁大眼鳕的产卵记录进行比较，表明产卵时间随着鱼体大小的增加而增加。此外，产卵经验和产卵期之前获得的能量可能会影响鸡蛋的大小。