Cresswell B J, Galbraith G F, Barnett A, Harrison H B, Jones G P, McClure E C, Quimpo T J R, Hoey A S
College of Science and Engineering James Cook University Townsville Queensland Australia.
AIMS@JCU Australian Institute of Marine Science Townsville Queensland Australia.
Ecol Evol. 2025 Aug 28;15(9):e72044. doi: 10.1002/ece3.72044. eCollection 2025 Sep.
Gradients in light, temperature and hydrodynamics associated with water depth are important determinants of ecological communities in marine environments. While depth specialism in coral reef fishes has been extensively studied in shallow (< 30 m) coastal reef systems, less is known about how depth-associated drivers operate over the larger depth ranges on isolated pinnacle and seamount reef systems, which are known to support abundant assemblages of predatory fishes. Using remotely operated vehicles, we surveyed predatory fish assemblages across a 100 m depth gradient on three seamount reefs in the Coral Sea. We tested for declines in abundance and diversity, as well as differences in assemblage structure of predatory fishes among depth strata. Species richness and abundance decreased significantly with depth, with predator abundance declining fourfold between the shallowest (5 m) and deepest (95 m) depths surveyed, while species richness was halved. Despite this, compositional differences among depth zones were minimal, with most taxa spanning the full depth range, suggesting adaptations to the limited horizontal habitat available on seamounts. Depth-associated shifts in taxonomic composition were primarily attributed to a single predator family, reef sharks (Carcharhinidae), which increased in abundance at mesophotic depths. The capacity of a large number of predatory fish taxa to utilize a wide range of depths allows these organisms to access favoured thermal environments and may be a potential resilience mechanism under future environmental change. Further studies are needed to assess the implications of depth use for predator behaviour, trophodynamics and conservation strategies.
与水深相关的光照、温度和流体动力学梯度是海洋环境中生态群落的重要决定因素。虽然珊瑚礁鱼类的深度特化在浅海（<30米）沿海珊瑚礁系统中已得到广泛研究，但对于与深度相关的驱动因素如何在孤立的海山和海峰珊瑚礁系统的更大深度范围内发挥作用，我们了解较少，而这些系统已知支持大量掠食性鱼类的聚集。我们使用遥控潜水器，对珊瑚海三个海山珊瑚礁上100米深度梯度范围内的掠食性鱼类群落进行了调查。我们测试了掠食性鱼类在不同深度层的丰度和多样性下降情况，以及群落结构差异。物种丰富度和丰度随深度显著下降，在所调查的最浅（5米）和最深（95米）深度之间，掠食者丰度下降了四倍，而物种丰富度减半。尽管如此，不同深度带之间的组成差异很小，大多数分类群跨越了整个深度范围，这表明它们适应了海山上有限的水平栖息地。分类组成中与深度相关的变化主要归因于一个掠食者科，即礁鲨（真鲨科），其在中光深度的丰度增加。大量掠食性鱼类分类群利用广泛深度的能力使这些生物能够进入适宜的热环境，这可能是未来环境变化下的一种潜在恢复力机制。需要进一步研究来评估深度利用对掠食者行为、营养动力学和保护策略的影响。
