395 research outputs found

    Community Change within a Caribbean Coral Reef Marine Protected Area following Two Decades of Local Management

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    Structural change in both the habitat and reef-associated fish assemblages within spatially managed coral reefs can provide key insights into the benefits and limitations of Marine Protected Areas (MPAs). While MPA zoning effects on particular target species are well reported, we are yet to fully resolve the various affects of spatial management on the structure of coral reef communities over decadal time scales. Here, we document mixed affects of MPA zoning on fish density, biomass and species richness over the 21 years since establishment of the Saba Marine Park (SMP). Although we found significantly greater biomass and species richness of reef-associated fishes within shallow habitats (5 meters depth) closed to fishing, this did not hold for deeper (15 m) habitats, and there was a widespread decline (38% decrease) in live hard coral cover and a 68% loss of carnivorous reef fishes across all zones of the SMP from the 1990s to 2008. Given the importance of live coral for the maintenance and replenishment of reef fishes, and the likely role of chronic disturbance in driving coral decline across the region, we explore how local spatial management can help protect coral reef ecosystems within the context of large-scale environmental pressures and disturbances outside the purview of local MPA management.Funding was provided by the Saba Conservation Foundation ((SCF), King Abdullah University of Science and Technology, The Australian National University and Australian Research Council. The funders had no role in study design and analysis, decision to publish, or preparation of the manuscript. Staff of the SCF were involved in data collection

    Trade-offs associated with dietary specialization in corallivorous butterflyfishes (Chaetodontidae: Chaetodon )

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    Author Posting. © Springer, 2007. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Behavioral Ecology and Sociobiology 62 (2008) 989-994, doi:10.1007/s00265-007-0526-8.Increasing dietary specialisation is an inherently risky strategy because it increases a species’ vulnerability to resource depletion. However, risks associated with dietary specialisation may be offset by increased performance when feeding on preferred prey. Though rarely demonstrated, highly specialised species are expected to outperform generalists when feeding on their preferred prey, whereas generalists are predicted to have more similar performance across a range of different prey. To test this theory, we compared growth rates of two obligate coral-feeding butterflyfishes (Chaetodon trifascialis and C. plebeius) maintained on exclusive diets of preferred versus non-preferred prey. In the field, C. trifascialis was the most specialised species, feeding almost exclusively on just one coral species, Acropora hyacinthus. Chaetodon plebeius meanwhile, was much less specialised, but fed predominantly on Pocillopora damicornis. During growth experiments, C. trifascialis grew fastest when feeding on A. hyacinthus and did not grow at all when feeding on less preferred prey (P. damicornis and Porites cylindrica). Chaetodon plebeius performed equally well on both A. hyacinthus and P. damicornis (its preferred prey), but performed poorly when feeding on P. cylindrica. Both butterflyfishes select coral species that maximise juvenile growth, but contrary to expectations, the more specialised species (C. trifascialis) did not outperform the generalist (C. plebeius) when both consumed their preferred prey. Increased dietary specialisation, therefore, appears to be a questionable strategy as there was no evidence of any increased benefits to offset increases in susceptibility to disturbance.This work was supported by a National Science Foundation (USA) Graduate Research Fellowship to ML

    Dose-dependence and small-scale variability in responses to ocean acidification during squid, Doryteuthis pealeii, development

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    Author Posting. © The Author(s), 2019. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in , Zakroff, C., Mooney, T.A. & Berumen, M.L. Dose-dependence and small-scale variability in responses to ocean acidification during squid, Doryteuthis pealeii, development. Marine Biology, (2019), 166: 62. doi:10.1007/s00227-019-3510-8.Coastal squids lay their eggs on the benthos, leaving them to develop in a dynamic system that is undergoing rapid acidification due to human influence. Prior studies have broadly investigated the impacts of ocean acidification on embryonic squid, but have not addressed the thresholds at which these responses occur or their potential variability. We raised squid, Doryteuthis pealeii (captured in Vineyard Sound, Massachusetts, USA: 41° 23.370N 70° 46.418´W), eggs in three trials across the breeding season (May - September, 2013) in a total of six chronic pCO2 exposures (400, 550, 850, 1300, 1900, and 2200 ppm). Hatchlings were counted and subsampled for mantle length, yolk volume, hatching time, hatching success, and statolith morphology. New methods for analysis of statolith shape, rugosity, and surface degradation were developed and are presented (with code). Responses to acidification (e.g., reduced mantle lengths, delayed hatching, and smaller, more degraded statoliths) were evident at ~ 1300 ppm CO2. However, patterns of physiological response and energy management, based on comparisons of yolk consumption and growth, varied among trials. Interactions between pCO2 and hatching day indicated a potential influence of exposure time on responses, while interactions with culture vessel highlighted the substantive natural variability within a clutch of eggs. While this study is consistent with, and expands upon, previous findings of sensitivity of the early life stages to acidification, it also highlights the plasticity and potential for resilience in this population of squid.This material was based upon work supported by the National Science Foundation Graduate Research Fellowship under Grant No. 1122374 to CZ. This project was funded by National Science Foundation Grant No. 1220034 to TAM.2020-04-1

    Topography and biological noise determine acoustic detectability on coral reefs

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    Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Coral Reefs 32 (2013): 1123-1134, doi:10.1007/s00338-013-1069-2.Acoustic telemetry is an increasingly common tool for studying the movement patterns, behaviour, and site fidelity of marine organisms, but to accurately interpret acoustic data, the variability, periodicity and range of detectability between acoustic tags and receivers must be understood. The relative and interactive effects of topography with biological and environmental noise have not been quantified on coral reefs. We conduct two long-term range tests (one and four months duration) on two different reef types in the central Red Sea, to determine the relative effect of distance, depth, topography, time of day, wind, lunar phase, sea surface temperature and thermocline on detection probability. Detectability, as expected, declines with increasing distance between tags and receivers, and we find average detection ranges of 530 and 120 m, using V16 and V13 tags respectively, but the topography of the reef can significantly modify this relationship, reducing the range by ~70%, even when tags and receivers are in line-of-sight. Analyses that assume a relationship between distance and detections must therefore be used with care. Nighttime detection range was consistently reduced in both locations and detections varied by lunar phase in the four month test, suggesting a strong influence of biological noise (reducing detection probability up to 30%), notably more influential than other environmental noises, including wind-driven noise, which is normally considered important in open-water environments. Analysis of detections should be corrected in consideration of the diel patterns we find, and range tests or sentinel tags should be used for more than one month to quantify potential changes due to lunar phase. Some studies assume that the most usual factor limiting detection range is weather-related noise; this cannot be extrapolated to coral reefs.2014-08-1

    Cyphastrea kausti sp n. (Cnidaria, Anthozoa, Scleractinia), a new species of reef coral from the Red Sea

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    A new scleractinian coral species, Cyphastrea kausti sp. n., is described from 13 specimens from the Red Sea. It is characterised by the presence of eight primary septa, unlike the other species of the genus, which have six, ten or 12 primary septa. The new species has morphological affinities with Cyphastrea microphthalma, from which it can be distinguished by the lower number of septa (on average eight instead of ten), and smaller calices and corallites. This species was observed in the northern and central Red Sea and appears to be absent from the southern Red Sea

    Novel polymorphic microsatellite markers developed for a common reef sponge, Stylissa carteri

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    © The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Marine Biodiversity 43 (2013): 237-241, doi:10.1007/s12526-013-0151-x.Despite the ubiquitous role sponges play in reef ecosystem dynamics, little is known about population-level connectivity in these organisms. The general field of population genetics in sponges remains in its infancy. To date, microsatellite markers have only been developed for few sponge species and no sponge population genetics studies using microsatellites have been conducted in the Red Sea. Here, with the use of next-generation sequencing, we characterize 12 novel polymorphic loci for the common reef sponge, Stylissa carteri. The number of alleles per loci ranged between three and eight. Observed heterozygosity frequencies (Ho) ranged from 0.125 to 0.870, whereas expected (He) heterozygosity frequencies ranged from 0.119 to 0.812. Only one locus showed consistent deviations from Hardy-Weinberg equilibrium (HWE) in both populations and two loci consistently showed the possible presence of null alleles. No significant linkage disequilibrium was detected for any pairs of loci. These microsatellites will be of use for numerous ecological studies focused on this common and abundant sponge.This work was funded by the King Abdullah University of Science and Technology

    Movements of the reef manta ray (Manta alfredi) in the Red Sea using satellite and acoustic telemetry

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    Populations of mobulid rays are declining globally through a combination of directed fisheries and indirect anthropogenic threats. Understanding the movement ecology of these rays remains an important priority for devising appropriate conservation measures throughout the world’s oceans. We sought to determine manta movements across several temporal and spatial scales with a focus on quantifying site fidelity and seasonality in the northern Farasan Banks, Red Sea. We fitted manta rays with acoustic transmitters (n = 9) and pop-up satellite archival transmitting (PSAT) tags (n = 9), including four with GPS capability (Fastloc), during spring 2011 and 2012. We deployed an extensive array of acoustic receivers (n = 67) to record movements of tagged mantas in the study area. All acoustically tagged individuals traveled frequently among high-use receiver locations and reefs and demonstrated fidelity to specific sites within the array. Estimated and realized satellite tag data indicated regional movements <200 km from the tagging location, largely coastal residency, and high surface occupation. GPS-tagged individuals regularly moved within the coastal reef matrix up to ~70 km to the south but continued to return to the tagging area near the high-occupancy sites identified in the acoustic array. We also tested the accuracy of several geolocation models to determine the best approach to analyze our light-based satellite tag data. We documented significant errors in light-based movement estimates that should be considered when interpreting tracks derived from light-level geolocation, especially for animals with restricted movements through a homogenous temperature field. Despite some error in satellite tag positions, combining results from PSAT and acoustic tags in this study yielded a comprehensive representation of manta spatial ecology across several scales, and such approaches will, in the future, inform the design of appropriate management strategies for manta rays in the Red Sea and tropical regions worldwide

    Tracing carbon flow through coral reef food webs using a compound-specific stable isotope approach

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    Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Oecologia 180 (2016): 809-821, doi:10.1007/s00442-015-3475-3.Coral reefs support spectacularly productive and diverse communities in tropical and sub26 tropical waters throughout the world’s oceans. Debate continues, however, on the degree to which reef biomass is supported by new water column production, benthic primary production, and recycled detrital carbon. We coupled compound-specific δ13C analyses with Bayesian mixing models to quantify carbon flow from primary producers to coral reef fishes across multiple feeding guilds and trophic positions in the Red Sea. Analyses of reef fishes with putative diets composed primarily of zooplankton (Amblyglyphidodon indicus), benthic macroalgae (Stegastes nigricans), reef-associated detritus (Ctenochaetus striatus), and coral tissue (Chaetodon trifascialis) confirmed that δ13C values of essential amino acids from all baseline carbon sources were both isotopically diagnostic and accurately recorded in consumer tissues. While all four source end-members contributed to the production of coral reef fishes in our study, a single source end-member often dominated dietary carbon assimilation of a given species, even for highly mobile, generalist top predators. Microbially-reworked detritus was an important secondary carbon source for most species. Seascape configuration played an important role in structuring resource utilization patterns. For instance, L. ehrenbergii, showed a significant shift from a benthic macroalgal food web on shelf reefs (71 ± 13% of dietary carbon) to a phytoplankton-based food web (72 ± 11%) on oceanic reefs. Our work provides insights into the roles that diverse carbon sources play in the structure and function of coral reef ecosystems and illustrates a powerful fingerprinting method to develop and test nutritional frameworks for understanding resource utilization.This research was based on work supported by Awards USA 00002 and KSA 00011 from King Abdullah University of Science and Technology (KAUST); additional funding was provided by the Woods Hole Oceanographic Institution (WHOI), a KAUST-WHOI award (SPCF-7000000104), and KAUST baseline research funds.2016-11-2

    A connectivity portfolio effect stabilizes marine reserve performance

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    Well-managed and enforced no-take marine reserves generate important larval subsidies to neighboring habitats and thereby con-tribute to the long-term sustainability of fisheries. However, larval dispersal patterns are variable, which leads to temporal fluctua-tions in the contribution of a single reserve to the replenishment of local populations. Identifying management strategies that mit-igate the uncertainty in larval supply will help ensure the stability of recruitment dynamics and minimize the volatility in fishery catches. Here, we use genetic parentage analysis to show extreme variability in both the dispersal patterns and recruitment contribu-tion of four individual marine reserves across six discrete recruit-ment cohorts for coral grouper (Plectropomus maculatus) on the Great Barrier Reef. Together, however, the asynchronous contri-butions from multiple reserves create temporal stability in recruit-ment via a connectivity portfolio effect. This dampening effect reduces the variability in larval supply from individual reserves by a factor of 1.8, which effectively halves the uncertainty in the recruitment contribution of individual reserves. Thus, not only does the network of four marine reserves generate valuable larval subsidies to neighboring habitats, the aggregate effect of individual reserves mitigates temporal fluctuations in dispersal patterns and the replenishment of local populations. Our results indicate that small networks of marine reserves yield previously unrecog-nized stabilizing benefits that ensure a consistent larval supply to replenish exploited fish stocks

    Differences in demographic traits of four butterflyfish species between two reefs of the Great Barrier Reef separated by 1,200 km

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    Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Coral Reefs 31 (2012): 169-177, doi:10.1007/s00338-011-0838-z.Many species demonstrate variation in life history attributes in response to gradients in environmental conditions. For fishes, major drivers of life history variation are changes in temperature and food availability. This study examined large-scale variation in the demography of four species of butterflyfishes (Chaetodon citrinellus, C. lunulatus, C. melannotus, and C. trifascialis) between two locations on Australia’s Great Barrier Reef (Lizard Island and One Tree Island, separated by approximately 1200km). Variation in age-based demographic parameters was assessed using the re-parameterised von Bertalanffy growth function. All species displayed measurable differences in body size between locations, with individuals achieving a larger adult size at the higher latitude site (One Tree Island) for three of the four species examined. Resources and abundances of the study species were also measured, revealing some significant differences between locations. For example, for C. trifascialis, there was no difference in its preferred resource or in abundance between locations, yet it achieved a larger body size at the higher latitude location, suggesting a response to temperature. For some species, resources and abundances did vary between locations, limiting the ability to distinguish between a demographic response to temperature as opposed to a response to food or competition. Future studies of life histories and demographics at large spatial scales will need to consider the potentially confounding roles of temperature, resource usage and availability, and abundance / competition in order to disentangle the effects of these environmental variables.This work was supported by a National Science Foundation (USA) Graduate Research Fellowship (MLB) and by PADI Project A.W.A.R.E. (MLB).2012-11-1
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