Conservation and restoration of gar (Lepisosteidae) populations in North America are increasingly of interest to fisheries managers. Alligator Gar Atractosteus spatula are being stocked as age‐0 fish in efforts to re‐establish extirpated populations. However, gars are known to be highly cannibalistic in hatcheries, suggesting that age‐0 Alligator Gar introduced into natural habitats may face predation pressures from other gar species, limiting the likelihood of released fish recruiting to the population. Furthermore, introduced age‐0 gar may not have the proper prey resources for rapid growth that would facilitate recruitment to adulthood. Texoma Reservoir, located on the Oklahoma–Texas border, hosts four native gar species, including the Alligator Gar, whose population is supported by supplemental stocking of age‐0 fingerlings. We investigated feeding by age‐0 gar to obtain a baseline level of trophic ecology for this group of fishes, including the potential for poststocking cannibalism. Food webs were reconstructed via analysis of carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopes using Bayesian mixing model approaches. Isotopic values for age‐0 fish of all four gar species were similar. Invertebrates represented a large fraction of the diet for all gars, followed by Common Carp Cyprinus carpio and Grass Carp Ctenopharyngodon idella. Competitive interactions among Bluegill Lepomis macrochirus, White Bass Morone chrysops, White Crappie Pomoxis annularis, and young gar may occur for invertebrates, shads Dorosoma spp., and Western Mosquitofish Gambusia affinis but are likely short‐lived due to the rapid growth of age‐0 gar after their transition to piscivory. Trophic position of age‐0 Alligator Gar, Longnose Gar Lepisosteus osseus, and Spotted Gar Lepisosteus oculatus was positively related to TL, but this relationship was not observed for Shortnose Gar Lepisosteus platostomus. In Texoma Reservoir, the four native gar species, including stocked Alligator Gar, appear to have adequate food resources for recruitment, with little indication of within‐family or interspecific predation. This suggests that stocked Alligator Gar quickly acclimated to their new environment.

中文翻译：

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根据稳定同位素分析推论得克萨斯州Texoma水库的0龄Gar鱼的摄食生态

在北美，保护和恢复restoration（Lepisosteidae）种群越来越受到渔业管理者的关注。短吻鳄Gar Atractosteus锅铲为了重新建立灭绝种群而将它们作为0龄鱼类放养。但是，众所周知，鱼在孵化场中具有很高的食人性，这表明引入自然栖息地的0岁短吻鳄可能会面临其他鱼的捕食压力，从而限制了鱼类向种群中募集的可能性。此外，引入的0岁以下幼崽可能没有足够的猎物资源来快速成长，这将不利于成年。位于俄克拉荷马州-得克萨斯州边界的德克索水库，藏有四种本地种，其中包括扬子鳄Gar，其种群得到了0岁以上鱼种的补充放养。我们调查了0 gar年龄的摄食，以获得该组鱼类的营养生态基线水平，包括后期放养食人动物的潜力。¹³ C）和氮（δ ¹⁵ N）同位素使用贝叶斯模型混合方法。所有四种类的0岁以下鱼类的同位素值均相似。无脊椎动物所代表的饮食对所有南极考察的大部分，其次是鲤鱼鲤鱼和草鱼草鱼。无脊椎动物，树荫下的Dorosoma spp。和西部蚊子Gambusia affinis之间可能会发生Bluegill Lepomis macrochirus，White Bass Morone chrysops，White Crappie Pomoxis ringis和幼小gar之间的竞争性相互作用。但由于0 gar过渡到食肉动物后迅速生长，因此寿命很短。0岁扬子鳄Gar，Longnose Gar Lepisosteus osseus和斑点Gar Lepisosteus oculatus的营养位置与TL正相关，但对于Shortnose Gar Lepisosteus platostomus则没有观察到这种关系。在Texoma水库中，四种本地种，包括库存的鳄鱼Gar，似乎有足够的食物资源可供招募，几乎没有迹象表明有家庭内部或种间捕食。这表明存货充足的短吻鳄Gar很快适应了他们的新环境。