Mesophotic Depth Gradients Impact Reef Fish Assemblage Composition and Functional Group Partitioning in the Main Hawaiian Islands

Asher, Jacob; Williams, Ivor D.; Harvey, Euan S.

doi:10.3389/fmars.2017.00098

Cited by 45 publications

(49 citation statements)

References 77 publications

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“…Fish abundance changed with depth but without a clear directional pattern, with surveys from deeper depths exhibiting a greater amount of variability. Previous findings from Caribbean (Bejarano et al, 2014;Pinheiro et al, 2016), and Pacific reefs (Thresher and Colin, 1986;Fukunaga et al, 2016;Asher et al, 2017;Sih et al, 2017), largely support a decline in fish abundance with depth, although a recent survey, also from Bermuda, recorded a depth-related increase in fish abundance within 45 m and 80 m (Pinheiro et al, 2016). Interestingly, the depths examined for that study overlap with the 60 m depth band in our study, which exhibited the greatest variability in fish abundance between surveys.…”

Section: Trends In Fish Abundance Biomass and Richness With Depthsupporting

confidence: 60%

“…It is clear that adoption of protocols for standardizing the collection of data is key for the inter-comparability of future reef studies (Woodall et al, 2018). In addition, sitespecific characteristics such as structural habitat complexity (i.e., continuity of reef habitat, topography, availability of hard substratum) have been shown to affect fish community patterns (Brokovich et al, 2008;Garcia-Sais, 2010;Asher et al, 2017) (see also Table 3). Notably, we found benthic community and substratum composition to be most variable between depths of 60-200 m (Figures 6I,J), which overlaps with the studied depths (45-80 m) of the previous survey in Bermuda (Pinheiro et al, 2016).…”

Section: Trends In Fish Abundance Biomass and Richness With Depthmentioning

confidence: 99%

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Depth-Dependent Structuring of Reef Fish Assemblages From the Shallows to the Rariphotic Zone

et al. 2019

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Shallow coral reef ecosystems worldwide are affected by local and global anthropogenic stressors. Exploring fish assemblages on deeper reefs is therefore important to examine their connectivity, and to help understand the biodiversity, ecology, distinctiveness, evolutionary history and threats in this sparsely studied environment. Conducting visual surveys on the Bermuda slope and a nearby seamount at depths from 15 to 300 m, we document decreasing fish biomass and diversity with increasing depth. Fish assemblages were primarily depth-stratified, with distinct suites of species inhabiting shallow (<30 m depth) and upper (60 m) and lower (90 m) mesophotic coral ecosystems, and confirming the presence of a distinct rariphotic (∼150-300 m) assemblage. We also report evidence of anthropogenic pressures throughout our surveyed depths. Our results highlight the novelty of deeper reef fish faunas, therefore suggesting limited applicability of the deep reef refuge hypothesis, and showcase the vulnerability of deep reefs to targeted fishing pressure and invasive species.

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Section: Trends In Fish Abundance Biomass and Richness With Depthsupporting

confidence: 60%

Section: Trends In Fish Abundance Biomass and Richness With Depthmentioning

confidence: 99%

Depth-Dependent Structuring of Reef Fish Assemblages From the Shallows to the Rariphotic Zone

et al. 2019

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“…The changes observed here, using presence/absence data of many diverse taxa, are likely to be indicative of changes in community structure and of changes in community composition, if combined with the observations of changes in abundance with depth (e.g., . Although the generality of the community break at ~ 60 m has been questioned (e.g., Pyle et al, 2016, based on fish assemblages in Hawaii), this evidence is equivocal; many other studies indicate that fish assemblages from Hawaii and elsewhere differ significantly with increasing depth into the mesophotic zone (Asher, Williams, & Harvey, 2017;Baldwin, Tornabene, & Robertson, 2018;Bejarano, Appeldoorn, & Nemeth, 2014;Pinheiro et al, 2016;Rocha et al, 2018). influence the community structure of MCEs (Bridge et al, 2012;Wolanski, Colin, Naithani, Deleersnijder, & Golbuu, 2004).…”

Section: Discussionmentioning

confidence: 99%

Global community breaks at 60 m on mesophotic coral reefs

Lesser

Slattery

Laverick

et al. 2019

Global Ecol Biogeogr

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Aim Mesophotic coral ecosystems (MCEs) are unique communities that support a high proportion of depth‐endemic species distinct from shallow‐water coral reefs. However, there is currently little consensus on the boundaries between shallow and mesophotic coral reefs and between upper versus lower MCEs because studies of these communities are often site specific. Here, we examine the ecological evidence for community breaks, defined here as species loss, in fish and benthic taxa between shallow reefs and MCEs globally. Location Global MCEs. Time period 1973–2017. Major taxa studied Macrophytes, Porifera, Scleractinia, Hydrozoa, Octocorallia, Antipatharia and teleost fishes. Methods We used random‐effects models and breakpoint analyses on presence/absence data to identify regions of higher than expected species loss along a depth gradient of 1–69 m, based on a meta‐analysis of 26 studies spanning diverse photoautotrophic and heterotrophic taxa. We then investigated the extent to which points of high faunal turnover can be explained by environmental factors, including light, temperature and nutrient availability. Results We found evidence for a community break, indicated by a significant loss of shallow‐water taxa, at ~ 60 m across several taxonomically and functionally diverse benthic groups and geographical regions. The breakpoint in benthic composition is best explained by decreasing light, which is correlated with the optical depths between 10 and 1% of surface irradiance. A concurrent shift in the availability of nutrients, both dissolved and particulate organic matter, and a shift from photoautotroph to heterotroph‐dominated assemblages also occurs at ~ 60 m depth. Main conclusions We found evidence for global community breaks across multiple benthic taxa at ~ 60 m depth, indicative of distinct community transitions between shallow and mesophotic coral ecosystems. Changes in the underwater light environment and the availability of trophic resources along the depth gradient are the most parsimonious explanations for the observed patterns.

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“…show declines (Asher et al 2017). Given that we detected a significant interaction between 538 depth and habitat complexity when predicting fish biomass (Table 5), it is likely that changes 539 in abundance are also affected by differences in benthic habitats.…”

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confidence: 87%

Highly diverse mesophotic reef fish communities in Raja Ampat, West Papua

Andradi-Brown

Beer

Colin

et al. 2019

Preprint

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21Mesophotic coral ecosystems (MCEs; reefs 30-150 m depth) are poorly studied, with 22 existing research heavily geographically biased away from the most species-rich reef 23regions. Yet, MCEs are of high interest because of their unique species and potential to act 24 as refuges from the impacts of fishing. Using baited remote underwater video systems, we 25 surveyed reef fish communities from depths of 2 to 85 m throughout the Raja Ampat 26 archipelago in West Papua, Indonesia -an area considered the heart of the Coral Triangle 27where coral reef biodiversity is greatest. Here we show-similar to shallow reefs-Raja 28Ampat MCEs are exceptionally diverse, with 152 fish species recorded at depths greater 29 than 40 m. We found that fish communities were highly depth driven, with declines in fish 30 abundance at increased depth. In contrast to previous studies elsewhere in the world, we 31 found that the proportion of planktivores declined across the shallow reef to MCE depth 32 gradient. While greater human population density correlated with lower reef fish biomass, 33we did not observe differential impacts based on depth, and so found no evidence that 34MCEs provide a depth refuge from fishing. Our results expand and contrast some previously 35 established MCE-depth patterns in fish communities, highlighting the need for future MCE 36

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Mesophotic Depth Gradients Impact Reef Fish Assemblage Composition and Functional Group Partitioning in the Main Hawaiian Islands

Cited by 45 publications

References 77 publications

Depth-Dependent Structuring of Reef Fish Assemblages From the Shallows to the Rariphotic Zone

Depth-Dependent Structuring of Reef Fish Assemblages From the Shallows to the Rariphotic Zone

Global community breaks at 60 m on mesophotic coral reefs

Highly diverse mesophotic reef fish communities in Raja Ampat, West Papua

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