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opencc-zeroMay 2022View details →

Linking variation in planktonic primary production to coral reef fish growth and condition

Within low nutrient tropical oceans, islands and atolls with higher primary production support higher reef fish biomass and reef organism abundance. External energy subsidies can be delivered onto reefs via a range of physical mechanisms. However, the influence of spatial variation in primary production on reef fish growth and condition is largely unknown. It is not yet clear how variability in food delivery onto a reef interacts with reef depth and slope, and affects reef fish productivity. Here we test the hypothesis that with increased proximity to deep-water oceanic allochthonous nutrient sources, or at sites where transportation of these water bodies onto reefs is facilitated by shallower reef slopes, parameters of fish growth and condition will be higher, and this pattern will be further emphasised in areas naturally higher in primary production. Contrary to expectations, we found no association between fish growth rate and sites with higher mean chlorophyll values. There were no differences in δ15N or δ13C values in fish collected at greater depths across reefs, suggesting a homogeneous primary production resource. However, the relationship between fish condition and primary production was influenced by depth of collection, driven by higher fish condition at shallow depths within a study site which is a 'hotspot' of primary production. Carbon δ13C values were depleted at sites with increasing primary production, and this trend was reversed by an interactive effect with shallower reef slopes. Our results indicate that deep-water ocean nutrient influences did not translate into observable increases in overall population growth in planktivorous Chromis fieldi within the 10–17.5 m depth range, but show the importance of site specific variation in hydrodynamics and reef physical characteristics influencing fish carbon isotopic composition and condition.

opencc-zeroJun 2022View details →

Data from: Millepora in Pleistocene coral reefs of Egypt

Millepora, a hydrozoan coral, is a common component in modern tropical reefs throughout the world. In ecological and palaeoecological surveys it is often grouped with scleractinian corals, which are the prevailing builders of coral reefs. On modern, current-exposed reefs in the Red Sea, Millepora can become the dominant coral. However, it is rarely found in fossil reefs and if present, its abundance is usually considerably lower than in modern reefs. The mismatch is often explained by a low preservation potential of the milleporid skeleton in the fossil record. We explore Millepora abundances in Pleistocene reefs of Egypt using 29 line transects (typically of 20 m length), and find its abundances to be comparable to that of adjacent modern reefs (between 0 and 18.8 ± 8.5 % per site). Comparisons between sites with and without Millepora suggest that site specific environmental characteristics determine the presence of Millepora in the fossil reef. We conclude that a lack of preservation of habitats preferred by Millepora instead of the preservation potential of the hydrozoan itself is the most plausible reason for the mismatch between modern and fossil abundances.

opencc-by-4.0Jun 2022View details →

Small predators dominate fish predation in coral reef communities

README File The dataset consists of 4 Excel files of which: -LizardData: is the fish community data collected on Lizard Island. -Metanalysis_dataset: is the gut content metanalysis, used to create the metanalsamps dataset, which is the dataset consisting the resampling and binning into body sizes.  This was then compared to the simnetsamps dataset, which is the resampling and binning from the LizardData file.

opencc-zeroJul 2022View details →

Shield wall: Kelps are the last stand against corals in tropicalised reefs

Communities inhabiting biogeographic transition zones are shifting in composition as a result of progressive warming and heatwaves. In the marine environment, corals are expanding onto higher latitude reefs historically dominated by temperate kelp forests, initiating a shift towards warm-affinity coral dominated states. Although these coral expansions are a global phenomenon, the mechanisms that are underpinning the expansion process remain poorly understood, which limits the projections of the rate and extent of ecosystem reconfiguration. Here, we investigated the interaction between the kelp Ecklonia radiata and the high latitude scleractinian coral Plesiastrea versipora in several of Western Australia's temperate reefs, where coral colony abundance has increased by 50% in recent years. Combining field surveys with field and laboratory experiments, we test the importance of physical (abrasion and light reduction) and chemical (allelopathic effects) effects of kelp canopies on coral tissue cover, photosynthetic parameters, and calcification rates. In the field, kelp cover had a negative effect on coral density that was overwhelming in comparison to other dominant macroalgal taxa. Abrasion by kelp whiplash was the predominant mechanism by which kelp exerted a negative effect on P. versipora fitness, scraping up to 80% of live coenosarc from experimental colonies. In contrast, canopies had no effects on P. versipora photochemical efficiency and laboratory incubations showed that there were no allelochemical effects from kelp on P. versipora. We conclude that E. radiata inhibits P. versipora establishment and development through abrasion, and the survey data confirmed that recent climate-driven kelp loss released corals from this effect, facilitating their expansion on high-latitude reefs in Western Australia. This shows how competitive interactions actively shield against species expansion in biogeographic transition zones and suggests a continued decline of kelp canopies will increase the permeability of temperate reefs to warm affinity species such as scleractinian corals.

opencc-zeroSep 2022View details →

Data from: Paternal hatching care regulates the timing, synchrony, and success of hatching in a coral reef fish

In oviparous species, the timing of hatching is a crucial decision, but for developing embryos, assessing cues that indicate the optimal time to hatch is challenging. In species with parental care, parents can assess environmental conditions and induce their offspring to hatch. We provide the first documentation of parental hatching regulation in a coral reef fish, demonstrating that male neon gobies (Elacatinus colini) directly regulate hatching by removing embryos from the clutch and spitting hatchlings into the water column. All male gobies synchronized hatching within 2h of sunrise, regardless of when eggs were laid. Paternally-incubated embryos hatched later in development, more synchronously, and had higher hatching success than artificially-incubated embryos that were shaken to simulate paternal hatching cues or not stimulated. Artificially-incubated embryos displayed substantial plasticity in hatching times (range: 88 – 244 hours post-fertilization), suggesting that males could respond to environmental heterogeneity by modifying the hatching time of their offspring. Finally, paternally-incubated embryos hatched with smaller yolk sacs and larger propulsive areas than artificially-incubated embryos, suggesting that paternal effects on hatchling phenotypes may influence larval dispersal and fitness. These findings highlight the complexity of fish parental care and may have important, and currently unstudied, consequences for fish population dynamics.

opencc-zeroSep 2022View details →

DNA metabarcoding confirms primary targets and breadth of diet for coral reef butterflyfishes

Understanding species-specific resource requirements is paramount in managing and protecting biodiversity in a world where environmental quality is in decline. Dietary data can inform predator–prey relationships and how changes in prey availability impact different species. However, for many coral reef fishes, prey and predatory events can be difficult to observe and identify, both in situ and within examined stomach samples. Here we applied DNA metabarcoding of stomach content samples for eleven Red Sea butterflyfish species to identify the diversity of dietary components that these primarily benthic feeding fish consume across coral reefs. Detections based on 18S and COI sequences from partially digested stomach contents significantly increased the resolution and diversity of the known diet for this group of fish, which included cryptic prey that are difficult to visually document due to soft parts or morphological ambiguity. In addition to scleractinian corals and other Cnidaria, the obligate corallivore species fed on a wide range of benthic organisms, whereas facultative species displayed a broader diet with crustaceans, tunicates, and worms contributing to samples. While a number of individuals contained DNA that could not be confidently identified using this method, the proportion of unidentifiable sequences was relatively low across butterflyfish species. The COI marker identified the importance of soft corals in the diet for two hard coral specialists; Chaetodon melannotus and Chaetodon semilarvatus, with soft coral detected in over half of the individuals and contributing significantly to the number of DNA sequence reads within their gut. Notably, five prey items identified to the species level were detected that are currently not documented in the Red Sea. Our analysis revealed that the diet of different species of butterflyfish significantly overlaps, with all species deriving most of their diet from the phylum Cnidaria (hard and soft coral, anemones) and symbiotic Symbiodiniaceae algae. Furthermore, accumulation curves suggest that all study species may feed on an even greater fraction of the benthos, likely driven by the availability and diversity of each individual/pair's associated territory. This approach increases the known dietary resolution and diversity of these key reef fishes and further enhances our understanding between butterflyfish and benthic organisms.

opencc-zeroSep 2022View details →

Data for: Long-wavelength-sensitive (lws) opsin gene expression, foraging and visual communication in coral reef fishes

Coral reef fishes are diverse in ecology and behaviour and show remarkable colour variability. Investigating the visual pigment gene (opsin) expression in these fishes makes it possible to associate their visual genotype and phenotype (spectral sensitivities) to visual tasks, such as feeding strategy or conspecific detection. By studying all major damselfish clades (Pomacentridae) and representatives from five other coral reef fish families, we show that the long-wavelength-sensitive (lws) opsin is highly expressed in algivorous and less or not expressed in zooplanktivorous species. Lws is also upregulated in species with orange/red colours (reflectance >520 nm) and expression is highest in orange/red-coloured algivores. Visual models from the perspective of a typical damselfish indicate that sensitivity to longer wavelengths does enhance the ability to detect the red to far-red component of algae and orange/red-coloured conspecifics, possibly enabling social signalling. Character state reconstructions indicate that in the early evolutionary history of damselfishes, there was no lws expression and no orange/red coloration. Omnivory was most often the dominant state. Although herbivory was sometimes dominant, zooplanktivory was never dominant. Sensitivity to long wavelength (increased lws expression) only emerged in association with algivory but never with zooplanktivory. Higher lws expression is also exploited by social signalling in orange/red, which emerged after the transition to algivory. Although the relative timing of traits may deviate by different reconstructions and alternative explanations are possible, our results are consistent with sensory bias whereby social signals evolve as a correlated response to natural selection on sensory system properties in other contexts.

opencc-by-4.0May 2021View details →

Fig. 1 in Histopatological effects of bleaching and disease on the coral Siderastrea stellata from coastal reefs of Brazil

Fig. 1. Areas where corals were sampled, Ponta do SeiXas, state of ParaÍba, Brazil.

opencc-zeroMay 2024View details →

Out of shape: Ocean acidification simplifies coral reef architecture and reshuffles fish assemblages

Climate change stressors are progressively simplifying biogenic habitats in the terrestrial and marine realms, and consequently altering the structure of associated species communities. Here, we used a volcanic CO2 seep in Papua New Guinea to test in situ if altered reef architecture due to ocean acidification reshuffles associated fish assemblages. We observed replacement of branching corals by massive corals at the seep, with simplified coral architectural complexity driving abundance declines between 60-86% for an assemblage of damselfishes associated with branching corals. An experimental test of habitat preference for a focal species indicated that acidification does not directly affect habitat selection behaviour, with changes in habitat structural complexity consequently appearing to be the stronger driver of assemblage reshuffling. Habitat health affected anti-predator behaviour, with P. moluccensis becoming less bold on dead branching corals relative to live branching corals, irrespective of ocean acidification. We conclude that coral reef fish assemblages are likely to be more sensitive to changes in habitat structure induced by increasing pCO2 than any direct effects on behaviour, indicating that changes in coral architecture and live cover may act as important mediators of reef fish community structures in a future ocean.

Fig. 3 in Decadal status of Acanthaster planci (Linnaeus, 1758) along the coral reef habitat of Andaman and Nicobar Islands

Fig. 3 — Depth-wise occurrence of A. planci (CoTS) in Andaman and Nicobar Islands

Fig. 2 in Decadal status of Acanthaster planci (Linnaeus, 1758) along the coral reef habitat of Andaman and Nicobar Islands

Fig. 2 — Zone-wise occurrence map of A. planci (CoTS) in Andaman and Nicobar Islands

Fig. 1 in Decadal status of Acanthaster planci (Linnaeus, 1758) along the coral reef habitat of Andaman and Nicobar Islands

Fig. 1 — Occurrence of A. planci (CoTS) in Andaman and Nicobar Islands

Fig. 5 in Decadal status of Acanthaster planci (Linnaeus, 1758) along the coral reef habitat of Andaman and Nicobar Islands

Fig. 5 — Substrate specificity of A. planci (CoTS) in reef habitat of Andaman and Nicobar Islands

opencc-zeroJun 2024View details →

Data from: Challenging trophic position assessments in complex ecosystems: calculation method, choice of baseline, trophic enrichment factors, season and feeding guild do matter. A case study from Marquesas Islands coral reefs

Assessments of ecosystem functioning are a fundamental ecological challenge and an essential foundation for ecosystem-based management. An understanding of species trophic positions (TP) is essential to characterize food web architecture. However, despite the intuitive nature of the concept, empirically estimating TP is a challenging task due to the complexity of trophic interaction networks. Various alternative methods are proposed to assess TPs, including different approaches to account for the different sources of organic matter at the base of the food web (the "baseline"). However, it is often not clear which methodological approach and which baseline choices are the most reliable. Using an ecosystem-wide assessment of a tropical reef (Marquesas Islands, French Polynesia, with available data for 70 coral reef invertebrate and fish species), we tested whether different commonly used TP estimation methods yield similar results and, if not, whether it is possible to identify the most reliable method. We found significant differences in TP estimates of up to 1.7 TP for the same species, depending on the method and the baseline used. When using bulk stable isotope data, the choice of the baseline significantly impacted TP values. Indeed, while δ15N values of macroalgae led to consistent TP estimates, those using phytoplankton generated unrealistically low TP estimates. The use of a conventional enrichment factor (i.e. 3.4 ‰) or a "variable" enrichment factor (i.e. according to feeding guilds) also produced clear discrepancies between TP estimates. Regarding the use of different calculation methods, TPs obtained with δ15N values of source amino acids (compound specifics isotope analysis) were close to those assessed with macroalgae, but evidenced the opposite seasonal pattern, with significantly lower TPs in winter than in summer for the majority of assessed species, with particularly pronounced differences for lower TP species. We use the observed differences to discuss possible drivers of the diverging TP estimates and the potential ecological implications.

opencc-by-4.0Nov 2014View details →

Figure 1 in Diversity of trypanorhynch metacestodes in teleost fishes from coral reefs off eastern Australia and New Caledonia

Figure 1. Collection localities off the east coast of Australia and New Caledonia.

Fig 6 in The status of coral reefs and reef fishes of Biloro Village, Southern Buru Regency, Indonesia

Fig 6: The percentage of coral reef fish at Biloro Village waters.

Fig 3 in The status of coral reefs and reef fishes of Biloro Village, Southern Buru Regency, Indonesia

Fig 3: Some of dominated hard coral found in study site.

Fig 2 in The status of coral reefs and reef fishes of Biloro Village, Southern Buru Regency, Indonesia

Fig 2: Distribution of life coral richness at Biloro waters reprsented by four sampling station.

Fig 5 in The status of coral reefs and reef fishes of Biloro Village, Southern Buru Regency, Indonesia

Fig 5: Other dominant fauna component found at study site

Fig 1 in The status of coral reefs and reef fishes of Biloro Village, Southern Buru Regency, Indonesia

Fig 1: Map of study site