Ecological Drivers of Invasive Lionfish (Pterois volitans and Pterois miles) Distribution Across Mesophotic Reefs in Bermuda

Invasive lionfish (Pterois volitans and P. miles) are now ubiquitous throughout the Caribbean and Western Atlantic on shallow and deep reefs. Recent surveys in Bermuda have revealed dense aggregations of lionfish on mesophotic reefs (60 m depth), yet these densities are not pervasive across reefs at this depth. Using diver-led visual surveys of mesophotic reef sites, this study examines how variations in potential ecological drivers may affect lionfish distribution. Significant correlations of lionfish densities were found with prey fish density and prey fish biomass, where sites with higher abundances of prey fishes have greater densities of lionfish. Furthermore, higher densities of lionfish also correlated significantly with higher juvenile Paranthias furcifer biomass, a preferred prey type for lionfish. Prey fish diversity, on the other hand, was not related to lionfish density, nor did prey fish community composition differ in a way that reflected lionfish distributions. The influence of seawater temperature was found to have the strongest effect on lionfish distribution, where higher lionfish densities were found at sites with lower bottom temperature. However, temperature co-varied with prey fish density, prey fish biomass, and P. furcifer biomass, implying that physical parameters of the environment (i.e., temperature) likely influence ecological parameters (i.e., prey fish abundance), contributing to the structuring of lionfish distributions. We suggest, therefore, that cold-water upwelling currents may be fueling the food chain in certain locations, resulting in high abundances of prey fishes and thus lionfish. Understanding the factors that influence lionfish distributions will ultimately increase the efficacy of management strategies, which, as the data presented here suggest, must incorporate mesophotic lionfish populations

Deep Reef Benthos of Bermuda: Field Identification Guide

Deep Reef Benthos of Bermuda builds on the video and imagery data collected during Nekton’s Mission – the XL Catlin Deep Ocean Survey - and provides a photographic guide for the visual identification of many of the corals, marine plants and other common invertebrates that inhabit Bermuda’s outer deep reefs.This guide is designed to aid marine biologists, divers and naturalists with the identification of organisms as seen in underwater footage or live in the field.</div

From polyps to pixels: understanding coral reef resilience to local and global change across scales

Abstract Context Coral reef resilience is the product of multiple interacting processes that occur across various interacting scales. This complexity presents challenges for identifying solutions to the ongoing worldwide decline of coral reef ecosystems that are threatened by both local and global human stressors. Objectives We highlight how coral reef resilience is studied at spatial, temporal, and functional scales, and explore emerging technologies that are bringing new insights to our understanding of reef resilience. We then provide a framework for integrating insights across scales by using new and existing technological and analytical tools. We also discuss the implications of scale on both the ecological processes that lead to declines of reefs, and how we study those mechanisms. Methods To illustrate, we present a case study from Kāneʻohe Bay, Hawaiʻi, USA, linking remotely sensed hyperspectral imagery to within-colony symbiont communities that show differential responses to stress. Results In doing so, we transform the scale at which we can study coral resilience from a few individuals to entire ecosystems. Conclusions Together, these perspectives guide best practices for designing management solutions that scale from individuals to ecosystems by integrating multiple levels of biological organization from cellular processes to global patterns of coral degradation and resilience

Population structure and connectivity in the Atlantic scleractinian coral Montastraea cavernosa (Linnaeus, 1767)

Coral reefs are increasingly threatened worldwide by a variety of biological and physical factors, including disease, bleaching and ocean acidification. Understanding levels of connectivity among widespread populations can assist in conservation efforts and the design of marine protected areas, as larval dispersal scales affect population demography. This study examined genetic connectivity and morphological variation of the broadcast spawning coral Montastraea cavernosa (L., 1767) among five locations in the Caribbean and Western Atlantic. Analysis of mtDNA and nuclear rRNA internal transcribed spacers, at both the local and regional scale, revealed that the majority of variation existed within locations rather than among them. Likewise, the majority of pairwise comparisons were non-significant between sites and locations. These results suggest that moderate to high gene flow occurs within and among populations of M. cavernosa in the Western Atlantic. The phylogeographic signature and significant pairwise comparisons among several locations, however, indicate that populations are also partially maintained through self-seeding and that gene flow may be restricted over large geographic distances. Additionally, while some anatomical variation is likely attributable to phenotypic plasticity, variations in skeletal morphology between Jamaica and other locations correspond with significant pairwise genetic distances and the presence of private sequence types (limited to a single location), suggesting selection to local environmental conditions.Organismic and Evolutionary Biolog

Population Structure of Montastraea cavernosa on Shallow versus Mesophotic Reefs in Bermuda.

Mesophotic coral reef ecosystems remain largely unexplored with only limited information available on taxonomic composition, abundance and distribution. Yet, mesophotic reefs may serve as potential refugia for shallow-water species and thus understanding biodiversity, ecology and connectivity of deep reef communities is integral for resource management and conservation. The Caribbean coral, Montastraea cavernosa, is considered a depth generalist and is commonly found at mesophotic depths. We surveyed abundance and size-frequency of M. cavernosa populations at six shallow (10m) and six upper mesophotic (45m) sites in Bermuda and found population structure was depth dependent. The mean surface area of colonies at mesophotic sites was significantly smaller than at shallow sites, suggesting that growth rates and maximum colony surface area are limited on mesophotic reefs. Colony density was significantly higher at mesophotic sites, however, resulting in equal contributions to overall percent cover. Size-frequency distributions between shallow and mesophotic sites were also significantly different with populations at mesophotic reefs skewed towards smaller individuals. Overall, the results of this study provide valuable baseline data on population structure, which indicate that the mesophotic reefs of Bermuda support an established population of M. cavernosa

Limited Gene Flow in the Brooding Coral Favia fragum (Esper, 1797)

Understanding population connectivity in corals is particularly important as these organisms are increasingly threatened by abiotic and biotic factors. This study examined the population genetic structure of the brooding coral Favia fragum across four locations in the Caribbean and Western Atlantic using mitochondrial and nuclear markers. Morphological features were also compared to test whether genetic diversity corresponds with skeletal morphology. When comparing across distantly related Caribbean and Bermudian locations, $F_{ST}$ values were high and significant, indicating strong genetic structure. At a local scale, significant genetic structure was found among reefs in Panama, while no genetic structure was found among reefs within Barbados, Bermuda or Jamaica. Surprisingly, a single haplotype for each of the three markers examined was found in Bermuda, where samples varied significantly from all other locations in three out of four morphological features analyzed. These data indicate that gene flow of F. fragum may occur locally among reefs but is highly restricted at distant locations. Furthermore, isolated populations, such as that of Bermuda, must be self-seeding to maintain the observed genetic uniformity.Organismic and Evolutionary Biolog

Do the shuffle: Changes in <i>Symbiodinium</i> consortia throughout juvenile coral development - Fig 4

<p><b><i>Symbiodinium</i> phylotype composition in various <i>Porites astreoides</i> life stages reared <i>in situ</i> (A) and <i>ex situ</i> (B).</b> (A) <i>Symbiodinium</i> phylotype composition of shallow <i>P</i>. <i>astreoides</i> adults, their brooded planulae, and newly settled juveniles reared <i>in situ</i> on shallow (10 m) and upper mesophotic (30 m) reefs. <i>Symbiodinium</i> phylotype frequencies differed significantly between (1) adults and planulae, (2) planulae and juveniles transplanted to the shallow reef, (3) planulae and juveniles transplanted to the upper mesophotic reef, and (4) between juveniles transplanted to the different depths. There was no difference in <i>Symbiodinium</i> phylotype frequencies between adults and juveniles transplanted to different depths. (B) <i>Symbiodinium</i> phylotype composition of planulae and <i>ex situ</i>, reared juvenile <i>P</i>. <i>astreoides</i>. No difference was found in <i>Symbiodinium</i> phylotype frequency of (1) planulae or juveniles from different parental depths or (2) between planulae and juvenile.</p

Comparative thermal performance of the reef-building coral Orbicella franksi at its latitudinal range limits

Temperature drives biological responses that scale from the cellular to ecosystem levels and thermal sensitivity will shape organismal functions and population dynamics as the world warms. Reef-building corals are sensitive to temperature due to their endosymbiotic relationship with single-celled dinoflagellates, with mass mortality events increasing in frequency and magnitude. The purpose of this study was to quantify the thermal sensitivity of important physiological functions of a Caribbean reef-building coral, Orbicella franksi, through the measurement of thermal performance curves (TPCs). We compared TPC metrics (thermal optimum, critical maximum, activation energy, deactivation energy, and rate at a standardized temperature) between two populations at the northern and southern extents of the geographic range of O. franksi. We further compared essential coral organismal processes (gross photosynthesis, respiration, and calcification) within a site to determine which function is most sensitive to thermal stress using a hierarchical Bayesian-modeling approach. We found evidence for differences in thermal performance, which could be due to thermal adaptation or acclimatization, with higher TPC metrics (thermal optimum and critical maximum) in warmer Panama, compared to cooler Bermuda. We also documented the hierarchy in thermal sensitivity of essential organismal functions within a population: respiration was less sensitive than photosynthesis, which was less sensitive than calcification. Understanding thermal performance of corals is essential for projecting coral reef futures, given that key biological functions necessary to sustain coral reef ecosystems are thermally mediated

Map of shallow (10 m) and upper mesophotic (30 m) sampling sites in Bermuda.

<p>Sites were used for adult <i>Porites astreoides</i> colony collection and juvenile transplantation.</p