Kim Myung Joon, Kim Ji Seong, Lee Yoon Ji, Park Joo Myun, Kwak Seok Nam, Shin Donghoon, Lee Sang Heon
Fisheries Resources Research Center, National Institute of Fisheries Science, Tongyeong, South Korea.
Department of Oceanography and Marine Research Institute, Pusan National University, Busan, South Korea.
Sci Rep. 2025 Jul 8;15(1):24436. doi: 10.1038/s41598-025-08438-9.
Understanding the dietary ecology of endangered species is essential for effective conservation. This study explores the trophic ecology of Hippocampus haema, an endangered seahorse species in South Korea, using stable isotope analysis (SIA). We assessed the feasibility of using the distal tail tip, which is rich in muscle tissue, for SIA to minimize specimen loss. Although this method has not been proven to be less invasive than fin clipping, it offers a practical alternative for small-sized or juvenile seahorses for which fin clipping provides insufficient tissue for analysis. A preliminary analysis confirmed that isotope values were consistent across different tail sections, validating the use of tail tips in dietary studies. We conducted two phases of analysis: (1) seasonal and size-based variation in δC and δN values using 36 specimens collected across four seasons (2015-2016), and (2) estimation of dietary contributions using a Bayesian mixing model (MixSIAR) based on δC and δN values of H. haema and six potential prey taxa collected in 2020. Seasonal variation was observed in δN values, with higher values in July, potentially reflecting breeding season dietary shifts. A significant positive correlation between isotopic values and body size suggests size-related changes in prey selection, though trophic position remained stable. MixSIAR results indicated that slower, smaller taxa such as Caprella, Harpacticoida, and Limnoria were the primary prey items, regardless. These findings provide insights into the feeding ecology and habitat reliance of H. haema, guiding conservation strategies to protect the species and its Sargassum-dominated habitat.
了解濒危物种的饮食生态对于有效保护至关重要。本研究利用稳定同位素分析（SIA）探索了韩国濒危海马物种——巴氏海马（Hippocampus haema）的营养生态学。我们评估了使用富含肌肉组织的尾尖进行SIA以尽量减少样本损失的可行性。尽管这种方法尚未被证明比剪鳍侵入性小，但它为小型或幼年海马提供了一种实用的替代方法，因为剪鳍提供的组织不足以进行分析。初步分析证实，不同尾段的同位素值是一致的，验证了在饮食研究中使用尾尖的可行性。我们进行了两个阶段的分析：（1）使用2015 - 2016年四季收集的36个样本，分析δC和δN值的季节和大小变化；（2）基于2020年收集的巴氏海马和六个潜在猎物类群的δC和δN值，使用贝叶斯混合模型（MixSIAR）估计饮食贡献。观察到δN值存在季节变化，7月的值较高，这可能反映了繁殖季节的饮食变化。同位素值与体型之间存在显著正相关，表明猎物选择随体型变化，尽管营养级保持稳定。MixSIAR结果表明，无论如何，像麦秆虫、猛水蚤和团水虱等行动缓慢、体型较小的类群是主要猎物。这些发现为巴氏海马的觅食生态和对栖息地的依赖提供了见解，为保护该物种及其以马尾藻为主的栖息地的保护策略提供了指导。
