Coral reef fish predator maintains olfactory acuity in degraded coral habitats

Micro-CT reconstruction reveals the colony pattern regulations of four dominant reef-building corals

Colonies are the basic geometric building blocks of coral reefs. However, the forming regulations of both colonies and reefs are still not understood adequately. Therefore, in this study, we reconstructed 25 samples using high-resolution micro-computed tomography to investigate coral growth patterns and parameters. Our skeleton and canal reconstructions revealed the characteristics of different coral species, and we further visualized the growth axes and growth rings to understand the coral growth directions. We drew a skeleton grayscale map and calculated the coral skeleton void ratios to ascertain the skeletal diversity, devising a method to quantify coral growth. On the basis of the three-dimensional (3D) reconstructions and growth parameters, we investigated the growth strategies of different coral species. This research increases the breadth of knowledge on how reef-building corals grow their colonies, providing information on reef-forming regulations. The data in this paper contain a large amount of coral growth information, which can be used in further research on reef-forming patterns under different conditions. The method used in this study can also be applied to animals with porous skeletons.

The 3D Reconstruction of Pocillopora Colony Sheds Light on the Growth Pattern of This Reef-Building Coral

Coral reefs are formed by living polyps, and understanding the dynamic processes behind the reefs is crucial for marine ecosystem restoration. However, these processes are still unclear because the growth and budding patterns of living polyps are poorly known. Here, we investigate the growth pattern of a widely distributed reef-building coral Pocillopora damicornis from Xisha Islands using high-resolution computed tomography. We examine the corallites in a single corallum of the species in detail, to interpret the budding, growth, and distribution pattern of the polyps, to reconstruct the growth pattern of this important reef-building species. Our results reveal a three-stage growth pattern of P. damicornis, based on different growth bundles that are secreted by polyps along the dichotomous growth axes of the corallites. Our work on the three-dimensional reconstruction of calice and inter-septal space structure of P. damicornis sheds lights on its reef-building processes by reconstructing the budding patterns.

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We use high-resolution computed tomography to investigate coral forming and polyp budding processes

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The calice reconstruction shows coral growth patterns and budding information

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Our work visualizes the growth pattern of Pocillopora damicornis

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High-resolution computed tomography is a method for future reef-building coral studies

Habitat degradation and predators have independent trait-mediated effects on prey

Coral reefs are degrading globally leading to a catastrophic loss of biodiversity. While shifts in the species composition of communities have been well documented associated with habitat change, the mechanisms that underlie change are often poorly understood. Our study experimentally examines the effects of coral degradation on the trait-mediated effects of predators on the morphology, behaviour and performance of a juvenile coral reef fish. Juvenile damselfish were exposed to predators or controls (omnivore or nothing) in seawater that had flowed over either live or dead-degraded coral over a 45d period. No interaction between water source and predator exposure was found. However, fish exposed to degraded water had larger false eyespots relative to the size of their true eyes, and were more active, both of which may lead to a survival advantage. Non-consumptive effects of predators on prey occurred regardless of water source and included longer and deeper bodies, large false eyespots that may distract predator strikes away from the vulnerable head region, and shorter latencies in their response to a simulated predator strike. Research underscores that phenotypic plasticity may assist fishes in coping with habitat degradation and promote greater resilience to habitat change than may otherwise be predicted.