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

Upper-mesophotic and shallow reef corals exhibit similar thermal tolerance, sensitivity and optima

The physiology of ectotherms living in marine environments is strongly influenced by their local thermal experience. Scleractinian corals living near their thermal optimums are increasingly vulnerable to bleaching and mortality as oceanic heat waves increase globally. Mesophotic coral ecosystems (MCEs) below 30 m depths are characteristically cooler than adjacent shallow water reefs, which according to theory should result in differential metabolic responses to temperature between depths. How local temperatures influence physiological responses in mesophotic corals is poorly understood. We compared thermal sensitivities of four coral species between a shallow (5–10 m) and upper-mesophotic (30−35 m) reef in Bermuda. Thermal performance curves (TPC) were measured in laboratory mesocosms for four common coral species (Diploria labyrinthiformis, Orbicella franksi, Montastraea cavernosa andPorites astreoides) across a wide range of temperatures (19−36). Our results indicate that the maximum rate of gross photosynthetic (GP) performance (GP-Pmax) and the mean overall photosynthetic rates (GP-lnc) varied significantly among species. In contrast, thermal sensitivity (Pmax, Topt, lnc, E, Eh, or Th) did not vary between depths for conspecifics except for deactivation energy (GP-Eh) in D. labyrinthiformis. Additionally, gross respiration (R) did not differ among species or between depths for any thermal metric. Similar metabolic responses between depths suggest that local adaptation and/or acclimatization to different thermal conditions is likely not occurring. Instead, upper-mesophotic corals in Bermuda do not have lower bleaching thresholds than shallow water conspecifics, but similar thermal sensitivities supporting the potential for MCEs to function as a thermal refuge

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

Environmental impacts of the deep-water oil and gas industry: a review to guide management strategies

The industrialization of the deep sea is expanding worldwide. Increasing oil and gas exploration activities in the absence of sufficient baseline data in deep-sea ecosystems has made environmental management challenging. Here, we review the types of activities that are associated with global offshore oil and gas development in water depths over 200 m, the typical impacts of these activities, some of the more extreme impacts of accidental oil and gas releases, and the current state of management in the major regions of offshore industrial activity including 18 exclusive economic zones. Direct impacts of infrastructure installation, including sediment resuspension and burial by seafloor anchors and pipelines, are typically restricted to a radius of ~100 m on from the installation on the seafloor. Discharges of water-based and low-toxicity oil-based drilling muds and produced water can extend over 2 km, while the ecological impacts at the population and community levels on the seafloor are most commonly on the order of 200–300 m from their source. These impacts may persist in the deep sea for many years and likely longer for its more fragile ecosystems, such as cold-water corals. This synthesis of information provides the basis for a series of recommendations for the management of offshore oil and gas development. An effective management strategy, aimed at minimizing risk of significant environmental harm, will typically encompass regulations of the activity itself (e.g., discharge practices, materials used), combined with spatial (e.g., avoidance rules and marine protected areas), and temporal measures (e.g., restricted activities during peak reproductive periods). Spatial management measures that encompass representatives of all of the regional deep-sea community types is important in this context. Implementation of these management strategies should consider minimum buffer zones to displace industrial activity beyond the range of typical impacts: at least 2 km from any discharge points and surface infrastructure and 200 m from seafloor infrastructure with no expected discharges. Although managing natural resources is, arguably, more challenging in deep-water environments, inclusion of these proven conservation tools contributes to robust environmental management strategies for oil and gas extraction in the deep sea.Copyright © 2016 Cordes, Jones, Schlacher, Amon, Bernardino, Brooke, Carney, DeLeo, Dunlop, Escobar-Briones, Gates, Génio, Gobin, Henry, Herrera, Hoyt, Joye, Kark, Mestre, Metaxas, Pfeifer, Sink, Sweetman and Witte. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms

Self-fertilization as a mechanism for population maintenance in a changing environment

The scientific aim of this study is to examine genetic diversity and parentage of B. europaea in the Mediterranean to determine the relative importance of self-fertilization for population maintenance and if the degree of self-fertilization varies with population demography, which can then be extrapolated to estimate the effects of changing seawater temperature. This goal will be achieved by conducting direct comparisons of progeny and parental genotypes using six previously developed B. europaea specific microsatellite loci. Levels of self- fertilization will be estimated using larvae collected from populations of varying density and results used to estimate the effects of environmental degradation and increasing seawater temperature

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