1 Universit´e de la Polyn´esie franácaise (UPF) – BP 6570, 98 702 FAA’A, Tahiti, French Polynesia
2 Universit´e de la Polyn´esie franácaise – BP 6570, 98 702 FAA’A, Tahiti, French Polynesia
3 Centre National de Recherche Scientifique (CNRS) – CNRS – Gif sur Yvette, Avenue de la Terrasse, France
4 IFREMER – BP 6570, 98 702 FAA’A, Tahiti, French Polynesia
5LEMAR – Laboratory IUEM LEMAR Technopole Brest – Technopˆole Brest-Iroise, rue Dumont d’Urville, 29280 Plouzan´e, France
In French Polynesia, fish aquaculture ofPlatax orbicularis is a sector in emergence. However bacterial infection byVibrio harveyiandTenacibaculum maritimumlimits its development. This study aims to identify if natural products from French Polynesia can be an efficient biosourcing to prevent bacterial infection in the aquaculture of P. orbicularis. Methodology consisted in a screening of live organisms in the inhibition of V. harveyi quorum sensing, then the isolation of natural products from these organisms and the identification of quorum sensing inhibitors.
Two natural products sourcing were studied, the plantMorinda citrifoliaand the marine sponge Leucetta chagosensis. Derivatives of aminoimidazole from Leucetta chagosensis were identified asquorum sensing inhibitors and lyophilized powder ofM. citrifolia was shown to protect fishes from bacteria in vivo. These results could be used as an alternative of antibiotic supply to prevent bacterial diseases in fish aquaculture.
C1/ The role of fishes on coral reefs
A morphological and functional basis for maximum prey size in piscivorous fishes
Michalis Mihalitsis ∗ 1,2, David Bellwood 1,2
1 James Cook University (JCU) – College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
2 Australian Research Council Centre of Excellence for Coral Reef Studies – James Cook University, Townsville, QLD, Australia
Trophic relationships within coral reef ecosystems are difficult to disentangle. While func- tional groups are recognized as important, the identity of such groups and their ecological roles remain unclear. Piscivorous fishes are widely recognized in coral reef ecosystems, however, large parts of their ecology still remain a mystery. One of the key questions is the size of their potential prey, since this can directly influence patterns of resource use. Our goal was to link morphology to performance and thereby establish potential function. In terms of the feeding ecology of pis- civorous fishes, the ‘gape’ has been widely recognized as a proxy for the prey sizes these fishes can consume. However, there is wide disparity in the literature on which specific measurement should be used; there does not appear for example, to be a consistent terminology for the term
‘gape’. This presentation will describe recent research clarifying the trophic morphology of the digestive tract of piscivorous fishes, comparing 18 potential ‘gapes’ with maximal performance.
Specifically, relevant gapes and their relationship to maximum prey size in piscivorous fishes that swallow their prey whole will be clarified. The specific morphological measurement that best describes maximal feeding performance in these fishes is also identified, highlighting previ- ously unconsidered morphological traits, such as the ability of tissues to stretch or prey to be compressed.
Assessing the Population Structure and Characterizing Spatio-temporal
Distributions of a Red Hind (Epinephelus guttatus) Spawning Aggregation in St.
Croix, U.S. Virgin Islands
Jonathan Brown ∗† 1, Richard Nemeth 2, Virginia Shervette 3
1 Master of Marine and Environmental Studies, University of the Virgin Islands – 2 John Brewers Bay St. Thomas, Virgin Islands 00802-9990, U.S. Virgin Islands
2 Center for Marine and Environmental Sciences, University of the Virgin Islands – 2 John Brewers Bay St. Thomas, Virgin Islands 00802-9990, U.S. Virgin Islands
3 Fish/Fisheries Conservation Lab, University of South Carolina Aiken – Aiken, SC 29801, United States
Red hind, Epinephelus guttatus, form fish spawning aggregations (FSA) within a seasonal no-take marine protected area (MPA) in St. Croix, U.S. Virgin Islands. To examine changes in population structure after ten and twenty years of seasonal protection differences among length, sex ratio and density were tested between baseline data and this study. Additionally, telemetry data collected over two consecutive spawning seasons tested if fish regularly cross the western MPA boundary. Results showed signs of a recovering spawning population with a significant increase in total length (TL) and a return from a leptokurtic to a bimodal size distribution.
Female-to-male sex ratios also showed improvement from 1:1 to 4:1, representing an appropriate ratio for this haremic spawning species. Conversely, mean density decreased by 55%. Telemetry recorded few detections along the MPA’s western boundary, but instead, sequential detections along its northwestern boundary revealed a migratory corridor not previously documented. De- tections also revealed high site fidelity within the MPA during primary spawning months, which concurs with the peak reproductive period for this species in the U.S. Virgin Islands. Although, numerous detections were also recorded within the MPA after the no-take period, suggesting temporal variability among known spawning months. Age structure data collected the following spawning season yielded a 9:1 female-to-male sex ratio with a mean age of 7 years at 33.8 cm TL. Findings emphasize the need to continue studies for understanding the density decrease and improving spatio-temporal resolution for better MPA design and FSA protection.
∗Speaker
†Corresponding author: Jembrwn@yahoo.com
Behavioral indicators provide insight into a fish’s perception of coral reefs: implications
for management.
Margaret Malone ∗ 1, Christopher Whelan 1, Joel Brown 1
1University of Illinois at Chicago (UIC) – 845 West Taylor Street (MC 066) Chicago, IL 60607-7104, United States
Fishes have long been suggested as indicators of coral reef quality. Traditionally, population surveys are used to measure and assess the effects of habitat degradation. While we learn a great deal through these assessments, they are unfortunately a trailing indicator, indicating a problem only after populations or communities have already changed. Coral reef managers can benefit from an assessment technique that is a leading indicator of the status of fish populations and communities. Foraging behavior may signal changes that occur prior to shifts in fish communi- ties. We apply foraging theory to supplement standard population and benthos assessments of patch coral reefs in Kane’ohe Bay, Hawaii. This approach allows us to gain insight into coral reef quality from the fish’s perspective and incorporates an assessment of ecological processes, such as predation. We hypothesize that a core habitat reef will have high fish density and high foraging intensity, while reefs of inferior value to the fish will have low density and low foraging intensity. Differences in foraging intensity among coral reefs reveals perceived predation risk and missed opportunities reflecting differences in background food availability. We selected study reefs of high and low quality using Hawaii’s Department of Aquatic Resources (DAR) survey data of invasive algae. Fish communities and substrate types, along with the foraging behavior of the abundant and widespread generalist invertivore, Thalassoma duperrey (saddle wrasse), were surveyed. We quantified foraging intensity as the giving-up density (GUD) from experi- mental food patches. Among reefs, we found that saddle wrasse density and foraging intensity was lower in low quality reefs. Based on our findings, we classified reefs into categories of core habitat, refuge, food for predators, and inferior habitat through the combination of behavioral indicators and population surveys. This information can be used to help maintain coral reef ecosystems and the populations and communities they support.
Collective Aggressiveness of Fish Social Groups Contributes to Variation in Coral
Replenishment
Sally Holbrook ∗ 1, Jonathan Pruitt 2, Russell Schmitt 1
1 University of California Santa Barbara – Marine Science Institute and Dept of Ecology, Evolution Marine Biology University of California Santa Barbara Santa Barbara, California 93106 USA, United
States
2 University of California Santa Barbara – Department of Ecology, Evolution and Marine Biology University of California Santa Barbara Santa Barbara, CA 93106, United States
Many animal societies exhibit stable intergroup differences in their collective behavior, yet the degree to which such differences impact broader ecological phenomena remains unclear, particularly on coral reefs. Farmerfish live in groups and collectively defend their gardens of palatable algae from intrusion. In French Polynesia, farmerfish (Stegastes nigricans) provide settlement and nursery habitats for coral because they mob corallivorous fish that attempt to enter their territories. Their role in providing nursery habitat for young branching corals (Acropora, Pocillopora) via territorial defense has been recognized for several decades – and has been argued to play a critical part in recovery of coral following disturbances. We tested for stable intergroup differences in collective vigilance and mobbing behavior in colonies of farmerfish in Moorea, French Polynesia. Our behavioral assays revealed large among-colony differences in collective aggression towards intruder fish. We examined whether the territories of aggressive groups provided greater protection to corals than non-aggressive groups. Surveys revealed that territories of aggressive groups naturally harbored greater numbers of branching corals than non-aggressive groups. Field experiments revealed that survival and growth of outplanted staghorn coral nubbins were positively correlated with levels of collective aggression, and with adequate protection, they can develop into a staghorn thicket. Our findings highlight the potential for significant ecological impacts of intergroup differences in collective behavior, and suggest that factors that increase the collective aggressiveness of farmerfish groups could enhance the protective value of their territories for the replenishment of coral populations.
∗Speaker
Coral-damselfish mutualism: effects on photosynthesis and links to predation risk
Sebastian Ferse ∗ 1, Robin Gauff 1,2, Sonia Bejarano 1, Nur Garc´ıa Herrera 1,3
1 Leibniz Centre for Tropical Marine Research (ZMT) – Leibniz-Zentrum f¨ur Marine Tropenforschung GmbH, Fahrenheitstr. 6, 28359 Bremen, Germany
2 Oceanography and Marine Environments department, Universit´e Pierre et Marie Curie – Universit´e Pierre et Marie Curie (UPMC) - Paris VI – 4 Place Jussieu, 75252 Paris cedex 05, France
3 Alfred-Wegener-Institut, Helmholtz-Zentrum fur Polar- und Meeresforschung (AWI) – Am Alten Hafen 26, Bremerhaven 27568, Germany
Close associations with live corals are widespread among fish species on coral reefs. A large number of species selectively recruit to living corals, and several maintain a strong bond with live coral as adults. Fish utilise their host coral as shelter from predators and for egg deposition and feeding, while corals benefit from the nutrients excreted by fish and the ventilation by sleep-swimming fish among coral branches at night. Nocturnal ventilation by fish has been demonstrated to mitigate oxygen depletion inside the coral colony. Current flows are beneficial for coral photosynthesis, and some photosynthetic cnidarians actively induce flow across their surfaces. However, the effects of fish ventilation on coral photosynthesis have not been studied to date. Shelter-seeking behaviour of coral dwelling fish is usually linked to predation risk, implying that changes in predator abundance may affect the extent of benefits corals derive from sheltering fish. Here, we report the results of respiration chamber measurements of the obligate coral-dwelling damselfish,Dascyllus marginatus, and its host coral,Stylophora pistillata.
When the damselfish was allowed to swim among the coral branches, net oxygen production was 22% higher than when the fish and coral were separated by a mesh barrier. Ventilation by D.
marginatus may augment coral photosynthesis by 3-6%, depending on the amount of time fish spend seeking shelter among coral branches on the reef. The relationship between predation risk and shelter-seeking behaviour was assessed in a field study of the coral-associated lemon damselfish, Pomacentrus moluccensis. Large damselfish ventured further away from their host coral than small ones. Unexpectedly, predator activity was positively related to the distance swum by large fish away from their host coral. This may indicate that P. moluccensis displays a form of sentinel behaviour, and implies that cascading effects of predation on host corals are complex and depend on the ontogenetic stage of individuals and social structure of the species.
Exploring the functional traits which may provide mechanism of assembly rules among
reef fishes from contrasting habitat types
Catalina Ruz ∗ 1, Vladimir Garmendia 1, Alejandro Perez Matus† 2
1 Subtidal Ecology Laboratory, Estaci´on Costera de Investigaciones Marinas, Pontificia Universidad Cat´olica de Chile, Santiago, Chile (SUBELAB) – Osvaldo Marin 1672, El Tabo-Las Cruces, Chile
2Subtidal Ecology Laboratory and Marine Conservacion Center, Estaci´on Costera de Investigaciones Marinas, Pontificia Universidad Cat´olica de Chile, Santiago, Chile (SUBELAB) – Osvaldo Marin 1672,
El Tabo-Las Cruces, Chile
A fundamental concern in community ecology is to understand how species assemblages form under different environmental conditions and which functional traits converge among commu- nities. Functional traits can reveal demographic processes that determine how species co-exist within communities. Reef fish offer a great diversity of functional traits establishing strong relationships with their habitat. In this study, we compared functional traits (ecological, mor- phological, and physiological) and habitat characteristic parameters (complexity, abundance of habitat features, rugosity and wave exposure) among reef fish from kelp, foliose algae, and coral-dominated ecosystems from continental Chile, Juan Fernandez Islands, and Rapa Nui Is- land, respectively. With the expectation that there is a direct and positive relationship between habitat-trait diversity and that of the corresponding traits of reef fish, we combined visual census methods, landmark geometric morphometry, fin aspect ratio, and routine oxygen consumption of the most abundant reef fish from these ecosystems. Results up-to date indicate that few organisms dominate the reef fish assemblages in these contrasting habitats. In spite of the tax- onomic differences, strong similarities in shape and form of reef fishes were present between temperate reef fishes from kelp and foliose algae dominated ecosystems from Continental Chile and Juan Fernandez, respectively. We also found slight variation in body shape and form within coral-dominated reef fish from Rapa Nui but strikingly different to those present in temperate ecosystems. We also found that abundant reef fishes have similar physiological traits (routine oxygen consumption) despite the environmental variability within each ecosystem. Finally, cer- tain habitat features- such as bottom rugosity, abundance of dominant habitat, and length of habitat- filter several traits within each ecosystem. We conclude that organisms are functionally able to match different environmental conditions and habitat characteristics via plasticity in phenotypic traits.
∗Speaker
†Corresponding author: aperez@bio.puc.cl
Fish as a primary source of reef carbonate sediment: an overlooked ecosystem process?
Michael Salter ∗ 1, Chris Perry 2, Rod Wilson 3, Alastair Harborne 4
1 University of Exeter – University of Exeter, College of Life and Environmental Sciences (Geography), Amory, Rennes Drive, Exeter, EX4 4RJ, UK, United Kingdom
2 University of Exeter – University of Exeter, College of Life and Environmental Sciences (Geography), Amory, Rennes Drive, Exeter, EX4 4RJ, UK, United Kingdom
3 University of Exeter – University of Exeter, College of Life and Environmental Sciences (Geography), Geoffrey Pope, Stocker Road, Exeter, EX4 4QD, UK, United Kingdom
4 Florida International University (FIU) – Department of Biological Sciences - Marine Sciences Program Florida International University, MSB 352, Biscayne Bay Campus, 3000 NE 151 Street, North
Miami, Florida 33181, USA, United States
Fishes play several key roles in coral reef sedimentary systems. In addition to well-known functions as bioeroders (e.g., parrotfishes) and as vectors of sediment removal from reefs (e.g., surgeonfishes), all marine fishes precipitate CaCO3 in their intestines as a waste product of os- moregulation, and thus represent a primary source of carbonate sediment. This ‘gut carbonate’
production is relevant in all marine settings, but its contribution to sediment loads is likely to be particularly significant in warm-water reef complexes, because: i) these systems can support high fish biomass; and ii) gut carbonate production rates correlate positively with temperature so will be relatively high. Unconsolidated sediment represents a volumetrically significant component of reef complexes that can influence both ecological and geomorphological processes, including recruitment potential, grazing preferences, and local water chemistry, whilst also supporting important benthic communities that include burrowing organisms and seagrasses. Thus, our understanding of reef ecosystems is incomplete without a detailed knowledge of the sedimentary processes (i.e., production, deposition, and preservation) operating within them. Regarding piscine gut carbonates, recent production models have highlighted their potential significance in sedimentary systems of The Bahamas. However, these datasets are poorly suited to wider as- sessments extending across contemporary warm-water reef settings, because: 1) many Bahamian reefs are extensively degraded and may support considerably lower fish biomass than healthier reefs in other systems; 2) atypical habitat configuration in The Bahamas means that production models generated there may be irrelevant elsewhere; and 3) gut carbonate mineralogy, which influences preservation potential, varies among fish families – but the limited number of families studied to-date means mineral phase quantification remains poorly constrained. Here we begin to address these issues using new datasets from relatively healthy reef systems of the Western Pacific that greatly expand the number of fish species ( ˜90) and families ( ˜40) studied. We
Fish-derived nutrients and their roles in Indo-Pacific coral reef systems
Burkepile Deron ∗ 1, Andrew Shantz 1, Jacob Allgeier 1, Valeriano Parravicini 2, S´ ebastien Vill´ eger 3, Katrina Munsterman 1, Russell