Supplemental stocking of crappie is a primary management strategy in many small southern reservoirs, but survival and contribution to the year-class in these systems is not known. We assessed the contribution of hatchery fish to the age-1 year-class within established crappie populations in four reservoirs ranging 29–74 ha in surface area. Chemically marked White Crappie Pomoxis annularis and magnolia crappie (Black Crappie Pomoxis nigromaculatus × ♀White Crappie) were stocked at 125 fish/ha in 2015 and 2016, respectively. We also stocked a renovated reservoir (40 ha) with White Crappie in 2015 to serve as a reference without intraspecific competition and to provide an estimate of marking efficacy and mark retention. The total length of wild age-0 fish at the time of stocking averaged 52–60 mm larger than that of their hatchery conspecifics. We only recaptured 11 marked crappie, 10 of which were from the reference reservoir. The recovery of only one hatchery fish from the supplemental stockings yielded a combined stocking contribution of 0.59%, or 0.71% when adjusted for marking efficacy (at least 83%). We concluded that supplemental stocking of crappie in smaller reservoirs is not effective under current the stocking protocols, as contributions <1% cannot justify hatchery and personnel costs. It may be possible to modify the stocking procedures, and potential modifications are discussed.

中文翻译：

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南方小水库补充鲫鱼放养评价

在南部的许多小型水库中，补充放养鲫鱼是主要管理策略，但尚不清楚这些系统中一年级的存活率和贡献。我们评估了孵化场鱼类对 1 岁龄级鱼类的贡献，这些鱼类在表面积为 29-74 公顷的四个水库中已建立的鲫鱼种群中。化学标记的 White Crappie Pomoxis ringis和 magnolia crappie (Black Crappie Pomoxis nigromaculatus× ♀White Crappie) 在 2015 年和 2016 年的放养量分别为 125 条鱼/公顷。我们还在 2015 年储存了一个带有 White Crappie 的翻新水库（40 公顷），作为没有种内竞争的参考，并提供标记功效和标记保留的估计。放养时野生 0 龄鱼的总长度平均比孵化场同种鱼大 52-60 毫米。我们只重新捕获了 11 个标记的克拉皮，其中 10 个来自参考水库。仅从补充放养中回收一条孵化鱼产生了 0.59% 的综合放养贡献，或在调整标记效果后的 0.71%（至少 83%）。我们得出的结论是，在当前的放养协议下，在较小的水库中补充放养克拉皮是无效的，因为贡献 < 1% 不能证明孵化场和人员成本是合理的。可以修改放养程序，并讨论了可能的修改。