Unbalanced population structure and reliance on intraspecific predation by largemouth bass in an agricultural pond with no available prey fish
Unbalanced population structure and reliance on intraspecific predation by largemouth bass in an agricultural pond with no available prey fish
复制标题
在没有可用猎物鱼的农业池塘中，种群结构不平衡以及大口黑鲈对种内捕食的依赖
DOI：
10.1080/02705060.2020.1853621
复制
发表时间：
2020
影响因子：
1.3
通讯作者：
Kikuchi Eisuke
中科院分区：
文献类型：
--
作者：
Yasuno Natsuru;Fujimoto Yasufumi;Shimada Tetsuo;Shikano Shuichi;Kikuchi Eisuke
肉食性大口黑鲈被引入许多地区，因捕食而对当地水生生物构成威胁，导致生物多样性大幅下降。在猎物稀缺的情况下，大口黑鲈被认为会吃掉较小的同种动物。然而，人们对这个物种对种内捕食的饮食依赖及其对种群结构的影响知之甚少。我们研究了大口黑鲈的长度频率分布，并在没有可用猎物鱼的农业池塘中使用稳定碳和氮同位素估计了它们对种内捕食的依赖。几乎所有个体大口黑鲈都是通过池塘排水系统收集的。在大口黑鲈种群中，主要长度类别由标准长度 (SL) 为 100-160 毫米的鱼类组成，而很少有测量标准长度 (SL) < 100 毫米的个体（一岁幼鱼）被收集。 R 混合模型中的稳定同位素分析结果表明，所有四个长度等级（105-146、165-180、216-246 和 300-337mm SL）的大口黑鲈主要以幼年同种鱼和红色沼泽小龙虾（克氏原螯虾）为食。一岁幼体可能会被其他不同体型的个体捕食。占主导地位的 100-160 毫米 SL 长度类可能在一年级幼鱼类中经历了微弱的捕食压力。因此，大口黑鲈种群数量不平衡，一年级幼鱼（< 100mm SL）很少，而 100-160mm SL 长度类占主导地位。
The carnivorous largemouth bassMicropterus salmoideshas been introduced to many regions and poses a threat to native aquatic organisms due to predation, resulting in a significant decrease in biodiversity. Under conditions of prey scarcity, the largemouth bass is thought to consume smaller conspecifics. However, little is known about this species’ dietary reliance on intraspecific predation and its impact on the population structure. We investigated the length–frequency distribution of largemouth bass and estimated their reliance on intraspecific predation using stable carbon and nitrogen isotopes in an agricultural pond with no available prey fish. Almost all individual largemouth bass were collected via the pond drainage system. Within the largemouth bass population, the dominant length class was composed of fish measuring 100–160mm standard length (SL), whereas few individuals measuring < 100mm SL (first-year juveniles) were collected. The results from a Stable Isotope Analysis in R mixing model indicated that all four length classes (105–146, 165–180, 216–246, and 300–337mm SL) of largemouth bass fed mainly on juvenile conspecifics and on red swamp crayfish (Procambarus clarkii). First-year juveniles could have been predated by other individuals of various sizes. The dominant 100–160mm SL length class may have experienced a weak predation pressure when they were in the first-year juvenile class. Consequently, the largemouth bass population was unbalanced, with few first-year juveniles (< 100mm SL) and dominance of a 100–160mm SL length class.