Behavioral ecology of coral reef fishes at spawning aggregation sites

Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution April 1998Coral reef fishes aggregate to spawn on certain locations of reefs. This thesis is an extensive investigation of the behavioral and ecological relations between spawning reef fishes, predators and their environment at a spawning aggregation site. Many hypotheses have been proposed regarding the adaptive nature of different diel reproductive cycles observed in coral reef fishes. This study quantified the spawning patterns of eleven different reef fish species at one location (Johnston Atoll, Central Pacific), while making simultaneous measurements of the environmental factors likely to affect the spawning behavior of reef fishes. The environmental variables measured included time of day, tides, current velocity, current speed and abundance of piscivorous predators, and were correlated with observed spawning outputs through multifactorial analyses. High interspecific variability in spawning patterns was found among the eleven monitored species. The majority of species spawned at a specific time of the day, in agreement with the timing of spawning described at other locations, indicative of a fixed general response by fishes across distribution areas. Spawning of most fishes with daytime spawning peaks was correlated with local changes in current direction and predatory risks, showing responses designed to reduce the mortality of propagules and adults. Dusk-spawning species generally did not respond to changes in flow direction and predator abundance, most likely due to their short spawning periods and the reduced predatory pressures that occurred at dusk. Tides did not seem to be used exclusively as synchronizing cues to adult fishes for spawning. The influence of current speed in determining diel timing of spawning varied among species, with some species showing responses to current speed while others showed no response. Predation is a selective force hypothesized to influence the spawning behavior of coral reef fishes. This study describes and quantifies the predatory activities of two piscivorous and three planktivorous species at a coral reef fish spawning aggregation site in Johnston Atoll (Central Pacific). To characterize predator-prey relations, the spawning behavior of prey species was quantified simultaneously with measurements of predatory activity, current speed and substrate topography. Diel activity patterns and predator-prey relations varied among the predatory species analyzed. The activity patterns of piscivores, measured both as abundance and attack rates, were high during the daytime, decreased during the late afternoon hours and reached a minimum at dusk. The abundance of piscivores was significantly correlated with the abundance of prey for only one (Caranx melampygus) of the two piscivorous species, while the other species (Aphareus furca) did not respond to prey abundance. The selection of certain prey species by piscivores was consistent with two different hypotheses: the satiation of predators and the differences in spawning behaviors among prey species. Two of the three planktivorous species fed most actively at dusk, and selected as prey those species of reef fishes that produced eggs of large size. The third planktivorous species fed at all times of the day. Spawning prey fishes were more abundant over substrates with complex topography where refuges from piscivores were abundant than over smooth substrates. Overall attack rates by piscivores on adult spawning fishes were higher than by planktivores feeding on recently released eggs. The diel spawning patterns displayed by reef fishes at the study site seem to be influenced by the diel activity and prey selection patterns of piscivores previously described. The highest diversity of prey species occurred at dusk, when piscivores were least abundant and overall abundance of prey fishes was lowest. The behavioral strategies used by the piscivore Caranx melampygus (Carangidae) while feeding on spawning aggregations of coral reef fishes were studied for two years at Johnston Atoll (Central Pacific). Visual behavioral observations revealed the existence of two different hunting behaviors employed by this predator. A 'midwater' hunting behavior, which consisted of midwater high speed attacks on spawning fishes, is typical of large sized transient predators and yielded a low capture success rate (2%). An 'ambush' hunting behavior consisted of attacks on spawning fishes from hiding locations in the substrate, and yielded a much higher capture success rate (17%). While ambushing their prey, C. melampygus displayed territorial aggressive behaviors toward other intruding conspecifics, defending a specific section of the reef. This specialized ambushing behavior is atypical of fast swimming carangids, but illustrates the behavioral flexibility of this predator. I suggest that the use of these two hunting behaviors by C. melampygus can potentially cause density-dependent mortality rates in prey communities, a demographic consequence previously attributed to the simultaneous action of various guilds of predatory species. Two species of trunkfishes (Ostraciidae) were observed spawning above a coral reef at Johnston Atoll (Central Pacific). This study analyzed the potential causes determining the difference in spawning ascent height in Ostracion meleagris (3.3 m average) and 0. whitleyi (1.5 m average). One hypothesis proposes that the risk of predation by piscivores influences how far each species can swim from the substrate, and that predation risk is greater for 0. whitleyi than 0. meleagris. Trunkfishes have an armoured exoskeleton and secrete an ichthyotoxic mucous under stress conditions, two defenses against predation. Because the two species used the same spawning grounds and spawned at approximately the same time, their size and toxicity levels were analyzed to assess their susceptibility to predation. Toxins were extracted from wild fishes and tested using a mosquitofish assay. Ostracion whitleyi was more toxic than 0. meleagris, refuting the predation-risk hypothesis. A second hypothesis proposes that long ascents are a way for spawning pairs to avoid disturbances by other male conspecifics. Observations of the spawning behaviours of the two species showed that male 0. meleagris were frequently involved in fighting episodes and showed high rates of male streaking (intruding nonpaired males attempting to fertilize eggs from spawning paired females), while none of these behaviours were observed in 0. whitleyi. The larger spawning height from the substrate may be an attempt by pairs of 0. meleagris to reduce the possibility of interference by other male conspecifics. Thus, the height of spawning ascents corresponds to the expectation from the male disturbance hypothesis, but not to the expectation of the predatory risk hypothesis.A fellowship form La Fundacion "La Caixa" allowed me to come to the WHOIJMIT Joint Program and generously funded me for two years. Travel to Johnston Atoll, part of my salary and many oceanographical toys were funded by the following grants to P.S. Lobel: U.S. Army Chemical Material Destruction Agency (via NOAA Sea Grant NA90-AA-D-SG535 and the Office of Naval Research N00014-91-J-1591 and N00014-92-J-1969) and the U.S. Army Legacy Resource Management Program (DAMD 17-93-J-3052). Finally the WHOI education office covered my tuition for a few years and paid for my attendance to scientific meetings. Funds were also received from the Thomas F. Westcott Fund for WHOI I MIT Joint Program Students, WHOI. Sea Grant project R/B- 134-PD, Coastal Research Center and Copeland Family Foundation

Behavioral ecology of coral reef fishes at spawning aggregation sites

Thesis (Ph. D.)--Joint Program in Biological Oceanography (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 1998.Includes bibliographical references.by Gorka Sancho.Ph.D

Leisure as a Space for Inclusion and the Improvement of Life Satisfaction of Immigrants

Immigration has increased as a transnational phenomenon in Europe in recent years. A total of 2.4 million people migrated to one of the EU-28 Member States during 2018 as discussed by Eurostat (2020). This new reality presents us with new challenges, barriers, and paradigms of intervention. In this context, leisure has become one of the most important tools for the inclusion of this population and the development and strengthening of civic values that are essential in these times of constant mobility and social and cultural hybridization as discussed by Ashcroft, Griffiths & Tiffin (2006). The aim of this study was to analyze the role of leisure in processes related to inclusion, improvement of life satisfaction, and those related to covering the needs of migrants. For this purpose, a questionnaire was used which was administered to 373 people from different countries of origin in the Basque Country (Northern Spain). The variables under study were participation in leisure activities, needs covered, life satisfaction, and perception of inclusion. The results indicate that the participation of these people in leisure activities and free time, their inclusion in the territory, and their perceived life satisfaction are all low, while their needs (physical, psychological, educational, social, relaxation, physiological, and artistic) are not satisfactorily covered. Furthermore, the extent to which their needs are covered, strength of the social network, inclusion, and life satisfaction all show a correlation with free time and engagement in leisure activities.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This research was supported by the KideOn Research Group of the Basque Government, Ref.: IT1342-19 (A category)

PREDATION STRUCTURES COMMUNITIES AT DEEP-SEA HYDROTHERMAL VENTS

The structure and dynamics of natural communities result from the interplay of abiotic and biotic factors. We used manipulative field experiments to determine the relative roles of abiotic conditions and biotic interactions in structuring deep-sea (2500 m depth) communities along environmental gradients around hydrothermal vents of the eastern tropical Pacific Ocean (East Pacific Rise, at 9°50' N). We tested (1) whether predation by crabs and fishes affects the recruitment of benthic species and subsequent community structure and (2) whether the effects of predation vary along the steep gradients of temperature, oxygen, sulfide, and metal concentrations near vents. Recruitment substrates (basalt cubic blocks, roughly 10 cm on a side), both uncaged and caged to exclude predators (crabs, fishes, whelks, and octopi), were deployed along a decreasing vent fluid-flux gradient. The exclusion of predators for 8 mo increased the abundance of small mobile gastropods and amphipod crustaceans but decreased the abundance of sessile invertebrates, including juvenile vestimentiferan worms, tubiculous polychaetes, and mussels. Effects of predation were strongest nearest to hydrothermal vents, where abiotic environmental conditions were most extreme but productivity and the overall abundances of benthic invertebrates and mobile predators were the greatest. Additional 5-mo experiments conducted at three different locations showed similar trends at all sites, indicating that these effects of predation on benthic community structure are repeatable. Stomach-content analyses of the most abundant predators found at vents indicated that the zoarcid fish (Thermarces cerberus) primarily feeds on the vent snail Cyathermia naticoides, the limpet Lepetodrilus elevatus, and the amphipod crustacean Ventiella sulfuris, the very species that showed the greatest increase following predator exclusion. In contrast, brachyuran (Bythograea thermydron) and galatheid (Munidopsis subsquamosa) crab stomachs did not contain small mobile grazers, and crabs presented with arrays of the most common vent invertebrate species preferred mussels and vestimentiferans over limpets. Our results indicate that predation by large mobile predators influences the structure of hydrothermal vent communities, directly by reducing the abundance of gastropod prey species, and indirectly by reducing gastropod grazing and by bulldozing of recruits of sessile invertebrates

Influence of Central Pacific Oceanographic Conditions on the Potential Vertical Habitat of Four Tropical Tuna Species

Climate change has resulted in the geographic and vertical expansion of oxygen minimum zones but their impact on the vertical distribution of commercially important species, such as tunas, is not well understood. Although La Nina events are characterized by increased upwelling along the equator, the increased primary productivity and bacterial proliferation drive the expansion of oxygen minimum zones. Vertical habitat of four tropical tuna species were characterized using direct observations of the oceanographic conditions of the Central Pacific Ocean during the 2008 La Nina event and existing primary literature on temperature and dissolved oxygen physiological tolerances for these tunas. Concentrations of potential prey were estimated using Acoustic Doppler Current Profiler raw backscatter and surface zooplankton tows. Based on the oceanographic conditions observed from February to Tune, low dissolved oxygen levels, more so than low temperatures, were inferred to restrict the predicted vertical habitat of four commercially important tuna species (bigeye, yellowfin, skipjack, and albacore). During peak La Nina conditions, temperature and dissolved oxygen tolerance limits of all four tuna species were reached at approximately 200 m. Zooplankton and myctophid fish densities peaked in the upper 200 in between 0 degrees N and 5 degrees N, which corresponded to a region with a shallow thermochne (150 m). Our findings suggest the possibility that competition and susceptibility to surface fishing gears may be increased for tropical tunas during a strong La Nina event due to vertical habitat restrictions

Accuracy of Healthcare Providers' Perception of Chest Compression Depth and Chest Recoil

Objective: The objective of this paper was to evaluate the validity and accuracy of healthcare providers' perception of chest compression depth and chest recoil during cardiopulmonary resuscitation (CPR). Methods: A clinical simulation study was performed with healthcare providers trained in CPR including physicians, nurses, and Emergency Medical Technicians (EMI). Following 2 minutes of hands-only-CPR on a sensor-programmed manikin, providers were able to respond to subjective questions assessing their adequacy of CPR. The providers' perception contrasted with the objective data obtained from the manikin. The validity and accuracy of CPR providers' perception of chest compression depth and chest recoil was assessed by the calculation of sensitivity, specificity and predictive values. Results: 180 Advanced or basic life support certified healthcare providers were enrolled. The degree of correlation between self-perception and actual performance was 52.2% in the thoracic compression depth and 61.7% in tic chest recoil. Caregivers' perception of chest compression depth had a sensitivity of 29.4% and a specificity of 87.3%. Caregivers' perception of chest recoil had a sensitivity of 30.3% and a specificity of 79.8%. Conclusions: Healthcare providers' perception for evaluating the accuracy of thoracic compressions is not as accurate as objective feedback methods during CPR This may impact patient outcomes during a cardiac arrest.This work was funded by the Bilbao-Basurto Integrated Healthcare Organisation (Osakidetza - Basque Health Service)

Stable Isotope Analysis of the Sandbar Shark, Carcharinus plumbeus: A Minimally Invasive Method for Comparison of Diet and Trophic Relationships between Genders, Locations, and Age Classes

The 2006 National Marine Fisheries Service SEDAR for large coastal sharks recommended the gathering of additional diet and trophic relationship data for the sandbar shark, Carcharinus plumbeus. No diet studies of any kind have been performed on South Carolina subpopulations of C. plumbeus, and stable isotope analysis has never been performed on this species. Muscle samples were taken from C. plumbeus caught by the South Carolina Department of Natural Resources and the Virginia Institute of Marine Science shark surveys. The analysis of δ13C and δ 15N from this muscle tissue is ongoing and will be compared with prey species and between other C. plumbeus samples to determine the diet and trophic level of South Carolina and Virginia subpopulations. Intra-subpopulation comparisons will be made to detect potential differences in diet and trophic level between sharks of different age classes and genders

Chronological and biological aging of the human left ventricular myocardium: Analysis of microRNAs contribution

Aging is the main risk factor for cardiovascular diseases. In humans, cardiac aging remains poorly characterized. Most studies are based on chronological age (CA) and disregard biological age (BA), the actual physiological age (result of the aging rate on the organ structure and function), thus yielding potentially imperfect outcomes. Deciphering the molecular basis of ventricular aging, especially by BA, could lead to major progresses in cardiac research. We aim to describe the transcriptome dynamics of the aging left ventricle (LV) in humans according to both CA and BA and characterize the contribution of microRNAs, key transcriptional regulators. BA is measured using two CA-associated transcriptional markers: CDKN2A expression, a cell senescence marker, and apparent age (AppAge), a highly complex transcriptional index. Bioinformatics analysis of 132 LV samples shows that CDKN2A expression and AppAge represent transcriptomic changes better than CA. Both BA markers are biologically validated in relation to an aging phenotype associated with heart dysfunction, the amount of cardiac fibrosis. BA-based analyses uncover depleted cardiac-specific processes, among other relevant functions, that are undetected by CA. Twenty BA-related microRNAs are identified, and two of them highly heart-enriched that are present in plasma. We describe a microRNA-gene regulatory network related to cardiac processes that are partially validated in vitro and in LV samples from living donors. We prove the higher sensitivity of BA over CA to explain transcriptomic changes in the aging myocardium and report novel molecular insights into human LV biological aging. Our results can find application in future therapeutic and biomarker research

A scientific synthesis of marine protected areas in the United States: status and recommendations

Marine protected areas (MPAs) are a key tool for achieving goals for biodiversity conservation and human well-being, including improving climate resilience and equitable access to nature. At a national level, they are central components in the U.S. commitment to conserve at least 30% of U.S. waters by 2030. By definition, the primary goal of an MPA is the long-term conservation of nature; however, not all MPAs provide the same ecological and social benefits. A U.S. system of MPAs that is equitable, well-managed, representative and connected, and includes areas at a level of protection that can deliver desired outcomes is best positioned to support national goals. We used a new MPA framework, The MPA Guide, to assess the level of protection and stage of establishment of the 50 largest U.S. MPAs, which make up 99.7% of the total U.S. MPA area (3.19 million km2). Over 96% of this area, including 99% of that which is fully or highly protected against extractive or destructive human activities, is in the central Pacific ocean. Total MPA area in other regions is sparse – only 1.9% of the U.S. ocean excluding the central Pacific is protected in any kind of MPA (120,976 km2). Over three quarters of the non-central Pacific MPA area is lightly or minimally protected against extractive or destructive human activities. These results highlight an urgent need to improve the quality, quantity, and representativeness of MPA protection in U.S. waters to bring benefits to human and marine communities. We identify and review the state of the science, including focal areas for achieving desired MPA outcomes and lessons learned from places where sound ecological and social design principles come together in MPAs that are set up to achieve national goals for equity, climate resilience, and biodiversity conservation. We recommend key opportunities for action specific to the U.S. context, including increasing funding, research, equity, and protection level for new and existing U.S. MPAs