scholarly journals Comparing mesophotic and shallow reef fish assemblages in the 'Au'au Channel, Hawaii: fish size, feeding guild composition, species richness, and endemism

2020 ◽  
Vol 96 (4) ◽  
pp. 577-592
Author(s):  
Raymond C Boland ◽  
K David Hyrenbach ◽  
Edward E DeMartini ◽  
Frank A Parrish ◽  
John J Rooney
Keyword(s):  
Species Richness ◽  
Reef Fish ◽  
Fish Assemblages ◽  
Reef Fishes ◽  
Feeding Guild ◽  
Shallow Reef ◽  
Guild Composition ◽  
High Conservation ◽  
Herbivore Species ◽  
Foraging Guilds

Mesophotic (30–150 m) reef fish assemblages in the 'Au'au Channel, between the Hawaiian Islands of Maui and Lanai, were compared visually with neighboring shallow (<30 m depth) reef fish assemblages for differences in structure. Between 2007 and 2011, approximately 7000 mesophotic and 4000 shallow reef fishes were identified, sized (standard length), and assigned to seven foraging guilds. The shallow water zone had more species than the mesophotic zone (99 vs 80, respectively). Mesophotic planktivores and two herbivore species were significantly larger than their shallow reef counterparts. Shallow reef fish assemblages had a higher Chao1 estimated species richness for herbivores and corallivores but not the other five foraging guilds. The differences between mesophotic and shallow fish assemblages indicate that both have unique communities of high conservation importance.

scholarly journals Reef fish communities are spooked by scuba surveys and may take hours to recover

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4886 ◽  
Author(s):  
Michael J. Emslie ◽  
Alistair J. Cheal ◽  
M. Aaron MacNeil ◽  
Ian R. Miller ◽  
Hugh P.A. Sweatman
Keyword(s):  
Species Richness ◽  
Reef Fish ◽  
Fish Assemblages ◽  
Ecological Monitoring ◽  
Reef Fishes ◽  
Fish Length ◽  
Initial Contact ◽  
Monitoring Programs ◽  
Species Of Conservation Concern ◽  
Initial Attraction

Ecological monitoring programs typically aim to detect changes in the abundance of species of conservation concern or which reflect system status. Coral reef fish assemblages are functionally important for reef health and these are most commonly monitored using underwater visual surveys (UVS) by divers. In addition to estimating numbers, most programs also collect estimates of fish lengths to allow calculation of biomass, an important determinant of a fish’s functional impact. However, diver surveys may be biased because fishes may either avoid or are attracted to divers and the process of estimating fish length could result in fish counts that differ from those made without length estimations. Here we investigated whether (1) general diver disturbance and (2) the additional task of estimating fish lengths affected estimates of reef fish abundance and species richness during UVS, and for how long. Initial estimates of abundance and species richness were significantly higher than those made on the same section of reef after diver disturbance. However, there was no evidence that estimating fish lengths at the same time as abundance resulted in counts different from those made when estimating abundance alone. Similarly, there was little consistent bias among observers. Estimates of the time for fish taxa that avoided divers after initial contact to return to initial levels of abundance varied from three to 17 h, with one group of exploited fishes showing initial attraction to divers that declined over the study period. Our finding that many reef fishes may disperse for such long periods after initial contact with divers suggests that monitoring programs should take great care to minimise diver disturbance prior to surveys.

Spatial assemblage structure of shallow-water reef fish in Southwest Australia

2020 ◽  
Vol 649 ◽  
pp. 125-140
Author(s):  
DS Goldsworthy ◽  
BJ Saunders ◽  
JRC Parker ◽  
ES Harvey
Keyword(s):  
Shallow Water ◽  
Reef Fish ◽  
Marine Environment ◽  
Fish Assemblages ◽  
Canopy Cover ◽  
Reef Fishes ◽  
Reef Fish Assemblage ◽  
Reef Type ◽  
Present Distribution ◽  
Southwest Australia

Bioregional categorisation of the Australian marine environment is essential to conserve and manage entire ecosystems, including the biota and associated habitats. It is important that these regions are optimally positioned to effectively plan for the protection of distinct assemblages. Recent climatic variation and changes to the marine environment in Southwest Australia (SWA) have resulted in shifts in species ranges and changes to the composition of marine assemblages. The goal of this study was to determine if the current bioregionalisation of SWA accurately represents the present distribution of shallow-water reef fishes across 2000 km of its subtropical and temperate coastline. Data was collected in 2015 using diver-operated underwater stereo-video surveys from 7 regions between Port Gregory (north of Geraldton) to the east of Esperance. This study indicated that (1) the shallow-water reef fish of SWA formed 4 distinct assemblages along the coast: one Midwestern, one Central and 2 Southern Assemblages; (2) differences between these fish assemblages were primarily driven by sea surface temperature, Ecklonia radiata cover, non-E. radiata (canopy) cover, understorey algae cover, reef type and reef height; and (3) each of the 4 assemblages were characterised by a high number of short-range Australian and Western Australian endemic species. The findings from this study suggest that 4, rather than the existing 3 bioregions would more effectively capture the shallow-water reef fish assemblage patterns, with boundaries having shifted southwards likely associated with ocean warming.

scholarly journals Coral settlement and recruitment responses to reef fish foraging and trait diversity

2021 ◽  
Author(s):  
Cher F Y Chow ◽  
Caitlin Bolton ◽  
Nader Boutros ◽  
Viviana Brambilla ◽  
Luisa Fontoura ◽  
...  
Keyword(s):  
Reef Fish ◽  
Fish Assemblages ◽  
Reef Fishes ◽  
Foraging Strategies ◽  
Coral Recruitment ◽  
Coral Settlement ◽  
Trait Divergence ◽  
Positive Effects ◽  
Recruitment Success ◽  
Trait Diversity

The process of coral recruitment is crucial to the healthy functioning of coral reef ecosystems, as well as recovery following disturbances. Fishes are key modulators of this process by feeding on algae and other benthic taxa that compete with corals for benthic space. However, foraging strategies within reef fish assemblages are highly diverse and the effect of foraging diversity on coral recruitment success remains poorly understood. Here, we test how the foraging traits of reef fishes affect coral settlement and juvenile success at Lizard Island, Great Barrier Reef. Using a multi-model inference approach incorporating six metrics of fish assemblage foraging diversity (foraging rates, trait richness, trait evenness, trait divergence, herbivore abundance, and benthic invertivore abundance), we found that herbivore abundance had positive effects on both coral settlement and recruitment success. However, foraging trait diversity had a negative effect on coral settlement but not on recruitment. Coral settlement was higher at sites with less trait diverse fish assemblages, specifically in trait divergence and richness. Moreover, these two trait diversity metrics were stronger predictors of coral settlement success compared to herbivore abundance. Our findings provide evidence that impacts mediated by fish foraging on coral juveniles can potentially be harmful during settlement, but the space-clearing effect overall remains advantageous. We show here that the variation of fish biodiversity across reefs can be a partial driver to spatially uneven patterns of coral recruitment and reef recovery.

scholarly journals Olfactory responses of coral-reef fishes to coral degradation and crown-of-thorns (Acanthaster planci)

2016 ◽  
Vol 67 (5) ◽  
pp. 605 ◽  
Author(s):  
Amy G. Coppock ◽  
Naomi M. Gardiner ◽  
Geoffrey P. Jones
Keyword(s):  
Coral Reef ◽  
Reef Fish ◽  
Chemical Cues ◽  
Fish Assemblages ◽  
Reef Fishes ◽  
Live Coral ◽  
Acanthaster Planci ◽  
Olfactory Responses ◽  
Olfactory Stimuli ◽  
Coral Reef Ecosystems

Coral degradation is a major threat towards the biodiversity of coral-reef ecosystems, either through the physical effects of environmental change, or biological agents such as crown-of-thorns (Acanthaster planci). Coral loss is leading to significant declines in reef-fish assemblages, particularly those dependent on live coral as settlement sites. Most reef fishes use olfactory stimuli at settlement; however, their ability to detect chemical stimuli from degraded corals or A. planci is unknown. Here, olfactory responses of juvenile reef fishes to the presence of stressed corals and A. planci were tested. Juveniles of eight common coral-associated species were subjected to a series of pair-wise choice tests, where the period of time spent in two differing water sources was noted. All species demonstrated a significant attraction towards healthy coral (≥76%), avoiding cues emitted by stressed coral colonies. When given the choice between a control water (untreated reef water) and water containing chemical cues from A. planci, most species elicited no response. Finally, when given the choice between chemical cues derived from feeding A. planci or the control, all species avoided A. planci (≥70%). Our results indicated that juvenile reef fish are capable of distinguishing the state of coral health, but not directly from disturbance agents.

Community structure of temperate reef fishes in kelp-dominated subtidal habitats of northern Chile

2007 ◽  
Vol 58 (12) ◽  
pp. 1069 ◽  
Author(s):  
Alejandro Pérez-Matus ◽  
Lara A. Ferry-Graham ◽  
Alfredo Cea ◽  
Julio A. Vásquez
Keyword(s):  
Species Richness ◽  
Fish Species ◽  
Fish Assemblages ◽  
Sea Water ◽  
Reef Fishes ◽  
Northern Coast ◽  
Northern Chile ◽  
Temperate Reef ◽  
Composition And Structure ◽  
Study Sites

An important aim of fish ecology is to understand and predict patterns of distribution and abundance in marine communities. Such patterns were examined at four kelp-dominated sites along the northern coast of Chile (19° through 30° S) over 1 year. Fish species richness, diversity and abundance estimates obtained via observational and destructive sampling methods were compared among sites as were habitat and environmental variables that characterised the sites; including sea water temperature below the surface, nutrients, productivity, visibility, density of macroalgae stands, and percentage cover of observed microhabitats (including understorey algae and faunal assemblages). In total, 19 fish species belonging to 14 families were observed from all sites. Species richness and diversity were highest in sites where kelp canopy was composed of two species and where kelp was densest, although only species diversity was significantly different among sites. The sites with high kelp density, in turn, sustained abundant habitat-forming species in the kelp understorey. Principal coordinate analysis indicated that the composition and structure of the fish assemblages varied significantly with depth at all study sites. The depth distribution of fishes was correlated with the arrangement of site-specific biological microhabitats, defined by the algae or invertebrate species that form the microhabitat. Temperature, productivity, and nutrients did not vary consistently across study sites, but did vary within individual sites. We suggest that kelp cover and composition strongly affects the diversity and distribution of fishes at shallow coastal habitats in northern Chile through the availability of microhabitats.

scholarly journals Tropical rhodolith beds are a major and belittled reef fish habitat

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rodrigo L. Moura ◽  
Maria L. Abieri ◽  
Guilherme M. Castro ◽  
Lélis A. Carlos-Júnior ◽  
Pamela M. Chiroque-Solano ◽  
...  
Keyword(s):  
Reef Fish ◽  
Trophic Structure ◽  
Fish Assemblages ◽  
Fish Habitat ◽  
Reef Fishes ◽  
Marine Biodiversity ◽  
Resources Management ◽  
Abundance And Distribution ◽  
Fish Habitats ◽  
Energy Pathways

AbstractUnderstanding habitat-level variation in community structure provides an informed basis for natural resources’ management. Reef fishes are a major component of tropical marine biodiversity, but their abundance and distribution are poorly assessed beyond conventional SCUBA diving depths. Based on a baited-video survey of fish assemblages in Southwestern Atlantic’s most biodiverse region we show that species composition responded mainly to the two major hard-bottom megahabitats (reefs and rhodolith beds) and to the amount of light reaching the bottom. Both megahabitats encompassed typical reef fish assemblages but, unexpectedly, richness in rhodolith beds and reefs was equivalent. The dissimilar fish biomass and trophic structure in reefs and rhodolith beds indicates that these systems function based on contrasting energy pathways, such as the much lower herbivory recorded in the latter. Rhodolith beds, the dominant benthic megahabitat in the tropical Southwestern Atlantic shelf, play an underrated role as fish habitats, and it is critical that they are considered in conservation planning.

scholarly journals Benthic structure drives butterflyfish species composition and trophic group abundance

2019 ◽  
Author(s):  
Miguel Barbosa ◽  
Neil Coupland ◽  
Clara Douglas ◽  
Ellen Harrison ◽  
Kelly M James ◽  
...  
Keyword(s):  
Species Richness ◽  
Coral Reef ◽  
Reef Fish ◽  
Coral Reef Fish ◽  
Fish Assemblages ◽  
Coral Cover ◽  
Food Sources ◽  
Fish Diversity ◽  
Live Coral ◽  
Benthic Composition

Corals provide structure and food sources vital for the maintenance of coral reef fish diversity. However, coral reefs are currently under threat from climate change, which has led to the largest recorded loss of live coral. The loss of live coral, and corresponding shift in reef benthic composition, are predicted to impact the abundance and composition of coral reef fish species and communities. In this study, we investigate the effect of changes in reef benthic composition (eg. live coral, dead coral, algae), on the diversity and composition in an assemblage of butterflyfish species, in Faafu Atoll in the Maldives after the 2016 bleaching event. We show that differences in community composition of butterflyfish are associated to benthic structure, reflecting species feeding preferences. Interestingly, however, we also show that lower coral cover is not associated to lower abundance and species richness of butterflyfish. Our results suggest that maintenance of coral reef structure after a disturbance provides key microhabitats to accommodate non-corallivorous butterflyfish, thus maintaining abundance and species richness. Overall our study provides support for regulation of richness and abundance of coral reef fish assemblages to short term changes in coral reef benthic composition after disturbance via turnover in composition.

scholarly journals Coral reef fish assemblages at Clipperton Atoll (Eastern Tropical Pacific) and their relationship with coral cover

2016 ◽  
Vol 80 (4) ◽  
pp. 479 ◽  
Author(s):  
Aurora M. Ricart ◽  
Fabián A. Rodríguez-Zaragoza ◽  
Carlos González-Salas ◽  
Marco Ortiz ◽  
Amílcar L. Cupul-Magaña ◽  
...  
Keyword(s):  
Species Richness ◽  
Coral Reef ◽  
Reef Fish ◽  
Coral Reef Fish ◽  
Fish Assemblage ◽  
Fish Assemblages ◽  
Coral Cover ◽  
Live Coral ◽  
Assemblage Composition ◽  
Live Coral Cover

Clipperton Atoll, one of the most isolated coral reefs worldwide, is of great scientific interest due to its geomorphology and high levels of endemism. This study explored the reef fish assemblage structure of Clipperton Atoll and its relationship with live coral cover. Nine stations were sampled at three sites and three depths (6, 12 and 20 m) around the reef, measuring fish species richness and biomass and hermatypic coral cover (at genus level). We evaluated variation in species richness, biomass and diversity of fish assemblages among sites and depths, as well as the relationship between the entire fish assemblage composition and live coral cover. The results showed that species richness and biomass were similar among sites, but differed across depths, increasing with depth. In contrast, diversity differed among sites but not among depths. Multivariate analyses indicated that fish assemblage composition differed among sites and depths in relation to changes in cover of coral of the genera Pocillopora, Porites, Pavona and Leptoseris, which dominate at different depths. The results showed that fish species richness and diversity were low at Clipperton Atoll and that, in isolated coral reefs with a low habitat heterogeneity and low human disturbance, live coral cover has a significant influence on the spatial variation of the reef fish assemblages. This study highlights the importance of coral habitat structure in shaping coral reef fish assemblages.

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