1 LIttoral ENvironnement et Soci´et´es - UMR 7266 (LIENSs) – Universit´e de La Rochelle, Centre National de la Recherche Scientifique : UMR7266 – Bˆatiment ILE 2, rue Olympe de Gouges 17 000 La
Rochelle, France
2 Biologie des Organismes et Ecosyst`emes Aquatiques (BOREA) – Museum National d’Histoire Naturelle, Universit´e Pierre et Marie Curie - Paris 6 : UM95, Centre National de la Recherche
Scientifique : UMR7208 – 7, rue Cuvier, CP 32, 75231 Paris Cedex 05, France
3 EA 7462 – Universit´e de Rennes I – EA 7462, Campus de Beaulieu, Bˆat 25, Av. du G´en´eral Leclerc, 35042 Rennes Cedex, France
4College of Bioresource Science, Nihon University – Fujisawa, Kanagawa 2520880, Japan
5 Graduate School of Agricultural and Life Sciences, The University of Tokyo – Bunkyo, Tokyo 1138657, Japan
6 LIttoral ENvironnement et Soci´et´es [La Rochelle] (LIENSs) – CNRS : UMR7266, Universit´e de La Rochelle – Bˆatiment Marie Curie Avenue Michel Cr´epeau 17 042 La Rochelle cx1 - Bˆatiment ILE 2, rue
Olympe de Gouges 17 000 La Rochelle, France
Anguilliform eel larvae are ubiquitously distributed in the surface layers of intertropical oceans. The mystery of their diet is seemingly being progressively unveiled, although a number of materials are known to be consumed as particulate organic matter that include zooplankton fecal pellets, discarded appendicularian houses, or marine snow, along with the DNA barcoding signatures being found of many types of organisms. In the context of two research cruises con- ducted by the R/V Hakuho Maru in the South Pacific in 2013 (February, austral summer, 5 mil- lion km2) and 2016 (August to September, austral winter, 12 million km2), the trophic network of leptocephali was described using carbon and nitrogen stable isotopes. Particulate organic matter (POM) was sampled using Niskin bottles at layers from the surface to the maximum fluorescence depth. Zooplankton (copepods, siphonophores, annelids etc.), and leptocephali from 5 families (Anguillidae, Congridae, Muraenidae, Nemichthyidae and Serrivomeridae) were collected using an Isaacs-Kidd Midwater Trawl. In 2016, additional sampling of micro-zooplankton was per- formed using a NORPAC net to target smaller zooplankton species. An unprecedented sampling effort covered 34 stations along 2 longitudinal transects (171◦E, 170◦W) between 7-30◦S in 2013 and 62 stations in 4 longitudinal transects (175◦E, 170◦W, 155◦W, 140◦W) between 5-25◦S in 2016. The sampling transects were set across 4 major currents of the region that are the South
was linked to nitrogen isotope ratios. A relative stability in carbon and nitrogen isotopic ratios of POM was observed in these 3 TN. Temporally, nitrogen and carbon isotope ratios were more homogenous in austral summer than in austral winter with leptocephali trophic networks that were less distinct. These results are discussed in terms of hydrographic/meteorological contexts and previous information about leptocephali diets.
Spawning Areas and Larval Dispersal and Recruitment Strategies of Anguillid eels in
the Indo-Pacific
Michael Miller ∗ 1, Katsumi Tsukamoto 1
1 Laboratory of Eel Science, Nihon University, Japan – 1866 Kameino, Fujisawa-shi, Kanagawa, 252-0880, Japan
After the Atlantic eel spawning areas were discovered in the Sargasso Sea, attention shifted to the Indo-Pacific where the other 17 species or subspecies of anguillid eels live, because their spawning areas were unknown. The Danish Round-the-World Expedition in 1928-1930 found an anguillid spawning area off West Sumatra, but where the other species spawn remained a mystery until the Japanese eel, Anguilla japonica, spawning area was discovered in the North Equatorial Current in 1991. In the years that followed, collections of small leptocephali revealed that the northern population of the widely distributed Giant Mottled eel, A. marmorata, and possibly A. luzonensis, spawn in or near the A. japonica spawning area, where eel eggs and spawning-condition adults were also collected recently. Surveys of the western South Pacific for leptocephali found evidence of offshore spawning by A. australis and A. reinhardtii and pop- up satellite-transmitting tagging studies of adult eels have pointed to possible spawning areas in the region. Tropical eels of A. borneensis and A. celebesensis were found to spawn locally in the Indonesian Seas, but the A. marmorata and A. bicolor bicolor living there appear to migrate out of the area to spawn. Understanding of where the 5 Indian Ocean anguillid species or subspecies spawn is limited and no clear evidence about where French Polynesia eels spawn has been obtained. Collectively, existing information indicates that multiple types of spawning locations and larval dispersal patterns must exist according to the relationships between species geographic ranges and the ocean currents to transport the larvae. Passive processes alone do not seem to explain the recruitment of larvae of some species to particular areas, but not to other nearby areas. Active swimming by late-stage larvae is implicated for species that must cross or detrain from strong boundary currents, and timing of metamorphosis factors are not sufficient to explain how some endemic species such asA. borneensis,A. luzonensis, and A. dieffenbachii can recruit to specific areas without using other behaviors as late-stage leptocephali or glass eels.
Future research will reveal more about the remarkable migrations and recruitment mechanisms of Indo-Pacific anguillid eels.
Temporal dynamics of the recruitment of three eel species in French Polynesia
Herehia Helme ∗ 1
1Ecole Doctorale 472 : Syst`emes Int´egr´es, Environnement et Biodiversit´e (EPHE) (ED 472 SIEB) – Ecole Pratique des Hautes Etudes – Ecole pratique des hautes ´etudes Ecole doctorale 46 rue de Lille
75007 Paris, France
Eels still represent a great mystery with their diadromous catadromous life cycle; they breed at sea and larvae migrate to fresh waters to grow and spend their adult life. In French Polynesia, eels are emblematic both ecologically, as top predators in rivers, and culturally as, according to Polynesian legends, they represent the creation of life. There are three species known in French Polynesia: Anguilla marmorata the ”marbled eel”, A. megastoma, the”mountain eel”
and A. obscura, the ”mud eel”. The present study is the first long-term follow-up (3 years) of the temporal dynamics of the recruitment of the three species in the valley Papenoo, the biggest of Tahiti island. The arrival of glass eels throughout the year was monitored; the species composition of the recruits and the state of the populations were assessed, enabling us to study the recruitment variation. This study also analysed environmental variables that may affect the recruitment. Our results revealed (i) a seasonal recruitment occurring during the new moons of the wet season from November to March with a peak between December and January, and (ii) that the three species arrive in the estuaries at the same period. This monitoring should be continued to improve our knowledge of the status of the populations of the three species found in French Polynesia. It should also be carried out over several rivers in order to compare the results.
∗Speaker
The leptocephalus larvae/marine snow food-web theory: pros, cons and
uncertainties after 20 years of investigations in the Indo-Pacific.
Eric Feunteun ∗ 1,2, Michael Miller 3, Chistine Dupuy 4, Alexandre Carpentier 5, Anthony Acou 2,6, Mari Kuroki 7, Aur´ elie Dessier 4, Shun
Watanabe 7, Jun Aoyama 7, Tsuguo Otake 7, Katsumi Tsukamoto 3
1 Biologie des Organismes et Ecosyst`emes Aquatiques (BOREA) – Museum National d’Histoire Naturelle, Universit´e Pierre et Marie Curie - Paris 6 : UM95, Centre National de la Recherche
Scientifique : UMR7208 – 7, rue Cuvier, CP 32, 75231 Paris Cedex 05, France
2 Mus´eum National d’Histoire Naturelle - Centre de Recherche et d’Enseignement sur les Syst`emes Cˆotiers, Dinard, France (MNHN - CRESCO, Dinard, France) – Museum National d’Histoire Naturelle -
MNHN (FRANCE) – 38 rue du Port Blanc, 35800 Dinard, France
3 Laboratory of Eel Science, Nihon University, Japan – 1866 Kameino, Fujisawa-shi, Kanagawa, 252-0880, Japan
4UMR - Liens, University of La Rochelle, France – UMR LienS - University of La Rochelle, France – Bat Ile, 2 rue Olympe de Gouges 17 000 La Rochelle, France
5Universit´e de Rennes1 – Universit´e de Rennes 1 – MNHN-CRESC0, 38 rue du Port Blanc, 35800 Rennes, France
6 MNHN - Unit´e Mixte de Service Patrimoine Naturel (UMS PatriNat) – Mus´ee National d’Histoire Naturelle - MNHN (France) – MNHN - CRESCO, 38 rue du Port Blanc, 35800 Dinard, France
7 the University of Tokyo – 1-1-1, Yayoi, Bunkyo, Tokyo 113-8657, Japan
Since the epic Danish around-the-world oceanographic cruise to collect leptocephali in 1938- 1939 led by Johannes Schmidt, the intertropical oceans have been known to host a high diversity and abundance of larval stages of anguilliform and elopomorph teleosts: the leptocephalus larvae.
They all share striking morphological features: large eyes, a transparent laterally flattened- body with only a thin muscle-layer. Some species reach lengths of>30 cm and ages of several months to > 1 year. Leptocephali are part of the micronekton that are mainly found in the ocean epipelagic layers. Despite these common features, little is known about their diet. Direct observations of thousands of specimens show that the majority of their guts are seemingly empty, but instead contain an apparent paste that could be consumed organic matter. Currently the leading hypothesis is that marine snow provides most of this organic matter paste. Marine Snow is formed by the agglomeration of a wide range of biologically produced and discarded materials that slowly sink while being processed and recycled to nutrients by a complex ecosystem of
7 families to planktonic and micronektonic organisms and POM that contains marine snow.
These results clearly show that all leptocephali seem to have a similar feeding ecology, which is at lower trophic levels than all micro-zooplankton, suggesting that they are part of the detrital food web. However, the findings using d15N and d13C ratios and fatty acid profiles that some taxa of leptocephali occupy different ranges of trophic positions in the lower food web, suggests there are mechanisms limiting competition for the same food sources or feeding depths. This identifies new research objectives to understand the role of soluble organic matter (i.e. TEPs) contained in the marine snow.
E2/ Cryptobenthic fishes: Ecology and evolution of the smallest marine
vertebrates
A wonderful radiation of cryptobenthic clingfishes along Australia’s Southern Coast
Kevin Conway ∗ 1, Cragen King 2, Glenn Moore 3
1 Dept. of Wildlife and Fisheries Sciences, Texas AM University – Rm 232, Wildlife, Fisheries Ecological Sciences Building (WFES), 2258 TAMU 534 John Kimbrough Blvd, College Station, Texas
77843-2258, United States
2Marine Biology Interdisciplinary Program, Texas AM University – Rm 232, Wildlife, Fisheries Ecological Sciences Building (WFES), 2258 TAMU 534 John Kimbrough Blvd, College Station, Texas
77843-2258, United States
3 Western Australian Museum – Perth, Australia
Clingfishes of the family Gobiesocidae ( ˜165 species and 50 genera of largely uncertain re- lationships) are archetypal cryptobenthic fishes. Fifteen species of clingfishes are found in the shallow temperate marine waters along Australia’s Southern Coast, representing seven described and three undescribed genera. This Southern Australian clingfish fauna not only includes ”typ- ical” looking clingfishes (e.g., Aspasmogaster, Cochleoceps and Creocele) but also diminutive macroalgae and seagrass specialists (e.g., certain members ofCochleoceps,Parvicrepis andPosi- donichthys), commensal cleaners (Cochleoceps), and strange eel-like forms (Alabes). Preliminary phylogenetic analyses of a multi-locus data set for over 80 species and 40 genera of clingfishes have uncovered a large clade comprising a subset of Southern Australian taxa, including Al- abes, Cochleoceps, Parvicrepis,Posidonichthys, and the undescribed Genus A, B and C. Within this clade,Cochleoceps and Genus A are not recovered as monophyletic and the strange eel-like Alabes are recovered in a sister group relationship with the diminutive macroalgae specialists Parvicrepis and Genus B. The diversity of body shapes and sizes, habitat specializations and behaviours represented within this Southern Australian clade is unparalleled within the Gobieso- cidae. An overview of this diversity as well as potential morphological characters that provide evidence for this clade of quintessential cryptobenthic fishes will be provided.
∗Speaker
Coral-Gobies as a Model System for Understanding the Evolution and
Maintenance of Sociality
Marian Wong ∗ 1, Martin Hing† 1, Selma Klanten 2, Mark Dowton 1
1 Faculty of Science, Medicine and Health [University of Wollongong] (UOW) – Northfields Ave, Wollongong NSW 2522, Australie, Australia
2University of Technology Sydney (UTS) – 15 Broadway, Ultimo NSW 2007, Australia
The phenomenon of sociality, whereby independently reproducing individuals came together to form one cooperative unit, has posed an evolutionary conundrum to biologists over many decades. This is because those individuals, once capable of reproducing, gave up their repro- ductive rights in order to become part of a social group. Despite many excellent theoretical and empirical studies testing key concepts of social evolution theory, there is still debate re- garding the relative importance of various factors favouring sociality, suggesting that there may not be a general explanation. Here, we discuss two potential improvements in the study of sociality that could aid in the progress of this field. The first relates to the choice of model system which has largely been biased towards terrestrial animals in the literature. In contrast, recent consideration of other taxa, particularly marine taxa, is slowly revealing that expanding our perspective can enhance our understanding of these concepts and generate novel insights.
The second improvement relates to the incorporation of a broader approach to testing concepts, by using different methodologies – namely observational, experimental and phylogenetic pro- tocols, to test predictions of key hypotheses. We illustrate how these two improvements have been enmeshed in one specific group of marine coral-reef fishes, the coral-dwelling gobies (genus Gobiodon). These species reside permanently within corals and exhibit a wide array of social systems, being either strictly pair-forming (asocial) or highly gregarious social groups (social).
We develop a phylogeny on which we map i) an index of sociality and ii) ecological variables for each species to demonstrate the evolutionary progress of social evolution and whether they are related to ecological factors (and key hypothesis). We then propose experimental work on these coral-goby species to accompany the phylogenetic comparisons. Therefore, by combining investigations of under-studied coral reef taxa with multiple methodologies, we can provide a more holistic approach towards understanding social evolution in animals in general.
Cryptobenthic fishes: the final frontier of vertebrate biodiversity on coral reefs
Simon Brandl ∗† 1, Christopher Goatley 2, Luke Tornabene 3, David Bellwood 4,5
1 Smithsonian Environmental Research Center – Edgewater, Maryland 21037, United States
2 University of New England – Armidale, NSW, 2350, Australia
3University of Washington – 1122 NE Boat St, Box 355020 Seattle, WA 98195-5020, United States
4 College of Science and Engineering, James Cook University (JCU) – College of Science Engineering James Cook University Townsville, QLD, Australia 4811, Australia
5 ARC Centre of Excellence for Coral Reef Studies (CoralCoE) – ARC Centre of Excellence for Coral Reef StudiesJames Cook University TownsvilleQueensland 4811 Australia, Australia
Cryptobenthic reef fishes represent the most diverse and abundant vertebrates on coral reefs. Yet, due to their diminutive size and elusive nature, these fishes are frequently over- looked in assessments of coral reef fishes. We also lack a robust definition of what constitutes a cryptobenthic fish. This is concerning because the few papers that have investigated cryp- tobenthic fishes on coral reefs suggest that these animals are of considerable significance in coral reef trophodynamics and highly susceptible to environmental change. Here, we summa- rize our knowledge, to date, on cryptobenhtic reef fishes, and provide a detailed assessment of their ecology, evolution, and life-history. We provide the first quantitative definition of cryp- tobenthic reef fish families, revealing that a relatively clear threshold separates families for which more than 10% of species are smaller than five centimeters (Aploactinidae, Apogonidae, Blenniidae, Bythitidae, Callionymidae, Chaenopsidae, Creediidae, Dactyloscopidae, Gobiesoci- dae, Gobiidae, Grammatidae, Labrisomidae, Opistognathidae, Plesiopidae, Pseudochromidae, Syngnathidae and Tripterygiidae) from large reef fishes. We then show that cryptobenthic reef fish families are morphologically distinct from large reef fishes and that they differ markedly in several aspects of their life history. Furthermore, we demonstrate that these characteristics evolved separately on multiple occasions, including two of the most successful radiations within acanthomorph fishes, the Gobiidae and the Blennioidei and relatives (including the Blennioidei, Pseudochromidae, Opistognathidae, Plesiopidae, and Grammatidae). However, after reviewing the literature on cryptobenthic fishes, we caution that our current understanding of cryptoben- thic fish communities is almost uniformly poor, with the localities of targeted collections being both scarce and spatially highly clustered. In addition, it appears that many species of crypto- benthic fishes are as yet undiscovered, especially in remote geographic areas and depths beyond 40 meters. Cryptobenthic reef fishes appear to have diverged rapidly, with many species that are highly adapted to their local micro-environment. Because ongoing human-induced disturbances cause widespread environmental change, we argue that a more substantial and coordinated ef- fort is needed to understand and monitor cryptobenthic reef fish communities worldwide. To this end, we suggest the use of innovative, standardized techniques along with the initiation of open-access databases on the identity, distribution, and ecology of cryptobenthic fishes.
∗Speaker
†Corresponding author: simonjbrandl@gmail.com
Hidden in plain sight: high cryptobenthic fish diversity on soft sediment habitats in
Southeast Asia