Dactylogyrids (Monogenoidea) parasitizing the gills of spinefoots (Teleostei: Siganidae): proposal of Glyphidohaptor n. gen., with two new species from the Great Barrier Reef, Australia, and G. plectocirra n. comb. from Ras Mohammed National Park, Egypt

Nine species of Siganus (Perciformes: Siganidae) were examined for dactylogyrids (Monogenoidea) from the Red Sea, Egypt; the Great Barrier Reef, Australia; and the South China Sea, China. Species of Tetrancistrum were found on siganids from all 3 localities; Pseudohaliotrema spp. were restricted to siganids from the Great Barrier Reef; and species representing Glyphidohaptor n. gen. were found on siganids from the Red Sea and Great Barrier Reef. Siganus argenteus from the Red Sea and Siganus vulpinus from the Great Barrier Reef were negative for dactylogyrid parasites. Glyphidohaptor n. gen. is proposed for 3 species (2 species new to science) and the new species are described: Glyphidohaptor phractophallus n. sp. from Siganus fuscescens from the Great Barrier Reef; Glyphidohaptor sigani n. sp. from Siganus doliatus (type host), Siganus punctatus, Siganus corallinus, and Siganus lineatus from the Great Barrier Reef; and Glyphidohaptor plectocirra (Paperna, 1972) n. comb. (= Pseudohaliotrema plectocirra Paperna, 1972) from Siganus luridus and Siganus rivulatus from the Red Sea.     

Elevated temperature reduces the respiratory scope of coral reef fishes

The capacity for marine fishes to perform aerobically (aerobic scope) is predicted to control their thermal tolerance and, thus, the impact that rapid climate change will have on their populations. We tested the effect of increased water temperatures on the resting and maximum rates of oxygen consumption in five common coral reef fishes at Lizard Island on the northern Great Barrier Reef, Australia. All species exhibited a decline in aerobic capacity at elevated water temperatures (31, 32 or 33 °C) compared with controls (29 °C); however, the response was much stronger in two cardinalfishes, Ostorhinchus cyanosoma and O. doederleini , compared with three damselfishes, Dascyllus anuarus, Chromis atripectoralis and Acanthochromis polyacanthus . Aerobic scope of the two cardinalfishes was reduced by nearly half at 31 °C compared with 29 °C, and virtually all capacity for additional oxygen uptake was exhausted by 33 °C. In contrast, the three damselfishes retained over half their aerobic scope at 33 °C. Such differences in thermal tolerance between species, and possibly families, suggest that the community structure of reef fish assemblages might change significantly as ocean temperatures increase. Populations of thermally tolerant species are likely to persist at higher temperatures, but populations of thermally sensitive species could decline on low-latitude reefs if individual performance falls below levels needed to sustain viable populations.     

Ostracoda (Crustacea) from Lizard Island,northern Great Barrier Reef,Australia. II. The family Paradoxostomatidae Brady & Norman, 1889

The present paper deals with the taxonomy of the ostracod family Paradoxostomatidae Brady & Norman, 1889 from the coral reefs around Lizard Island, northern Great Barrier Reef, Australia. 18 species were found, all of them belonging to the genusParadoxostoma Fischer, 1855. 2 species had been previously described from Heron Island, southern Great Barrier Reef. 1 species had been described from the Red Sea. 2 species are left in open nomenclature.     

Habitat selection and the colonization of new territories by Chromis viridis

The settlement and recruitment patterns of Chromis viridis were followed during three consecutive seasons along the reefs of Eilat, Red Sea. The findings, based on intensive field surveys and a translocation experiment, indicated a strong and repeatable preference for some, but not other, colonies of the branching coral Acropora eurystoma; with significantly more larvae settling onto preferred colonies that house conspecific adults and juveniles. Furthermore, these findings showed that, given high recruitment rates, settlement‐site selection could drive migration by adults and older juveniles. As only some C. viridis schools received direct settlement, it was suggested that settlement‐driven migration is responsible for the replenishment of those schools that do not receive settlement and to the colonization of previously unoccupied coral colonies.     

Phylogeography of western Pacific Leucetta 'chagosensis' (Porifera: Calcarea) from ribosomal DNA sequences: implications for population history and conservation of the Great Barrier Reef World Heritage Area (Australia)

Leucetta 'chagosensis' is a widespread calcareous sponge, occurring in shaded habitats of Indo-Pacific coral reefs. In this study we explore relationships among 19 ribosomal DNA sequence types (the ITS1-5.8S-ITS2 region plus flanking gene sequences) found among 54 individuals from 28 locations throughout the western Pacific, with focus on the Great Barrier Reef (GBR). Maximum parsimony analysis revealed phylogeographical structuring into four major clades (although not highly supported by bootstrap analysis) corresponding to the northern/central GBR with Guam and Taiwan, the southern GBR and subtropical regions south to Brisbane, Vanuatu and Indonesia. Subsequent nested clade analysis (NCA) confirmed this structure with a probability of > 95%. After NCA of geographical distances, a pattern of range expansion from the internal Indonesian clade was inferred at the total cladogram level, as the Indonesian clade was found to be the internal and therefore oldest clade. Two distinct clades were found on the GBR, which narrowly overlap geographically in a line approximately from the Whitsunday Islands to the northern Swain Reefs. At various clade levels, NCA inferred that the northern GBR clade was influenced by past fragmentation and contiguous range expansion events, presumably during/after sea level low stands in the Pleistocene, after which the northern GBR might have been recolonized from the Queensland Plateau in the Coral Sea. The southern GBR clade is most closely related to subtropical L. 'chagosensis', and we infer that the southern GBR probably was recolonized from there after sea level low stands, based on our NCA results and supported by oceanographic data. Our results have important implications for conservation and management of the GBR, as they highlight the importance of marginal transition zones in the generation and maintenance of species rich zones, such as the Great Barrier Reef World Heritage Area.     

Large–Scale Movement and Reef Fidelity of Grey Reef Sharks

Despite an Indo-Pacific wide distribution, the movement patterns of grey reef sharks (Carcharhinus amblyrhynchos) and fidelity to individual reef platforms has gone largely unstudied. Their wide distribution implies that some individuals have dispersed throughout tropical waters of the Indo-Pacific, but data on large-scale movements do not exist. We present data from nine C. amblyrhynchos monitored within the Great Barrier Reef and Coral Sea off the coast of Australia. Shark presence and movements were monitored via an array of acoustic receivers for a period of six months in 2008. During the course of this monitoring few individuals showed fidelity to an individual reef suggesting that current protective areas have limited utility for this species. One individual undertook a large-scale movement (134 km) between the Coral Sea and Great Barrier Reef, providing the first evidence of direct linkage of C. amblyrhynchos populations between these two regions. Results indicate limited reef fidelity and evidence of large-scale movements within northern Australian waters.     

Ostracoda (Crustacea) from Lizard Island,northern Great Barrier Reef,Australia. I. Families: Cytherellidae,Loxoconchidae, Cytherideidae,Cytheruridae, Paracytherideidae,Pectocytheridae, Krithidae,Cytheromatiidae, Bythocytheridae,Cytheridae

This paper deals with the taxonomy of the ostracod families Cytherellidae, Cytheridae, Cytheromatidae, Cytherideidae, Krithidae, Loxoconchidae, Paracytherideidae, Cytheruridae, Pectocytheridae and Bythocytheridae from the coral reefs around Lizard Island, northern Great Barrier Reef, Australia. 22 species belonging to these families were found. 7 species had been described from Australian coasts, 1 from the Red Sea and 1 with Indopacific-Westatlantic distribution. 9 species are newly described and 4 species remain in open nomenclature.     

Taxonomy, host-specificity and biogeography of Symmetrovesicula Yamaguti, 1938 (Digenea: Fellodistomidae) from chaetodontids (Teleostei: Perciformes) in the tropical Indo-west Pacific region

Combined molecular and morphological data demonstrate the presence of two species of Symmetrovesicula Yamaguti, 1938 in chaetodontid fishes from Australian waters. A total of 2,462 individuals of 46 species of chaetodontid at eight localities were dissected. Analysis of the rDNA ITS2 revealed the presence of three genotypes, two separated by a single base difference and the third differed from the other two by 10-11 base differences. Subsequent morphological examination identified a number of variations that supported the presence of two species; however, we found no additional evidence to support the presence of a third species corresponding to the single base variation. Thus, we take the conservative approach of recognising two species of Symmetrovesicula within Australian waters, S. chaetodontis Yamaguti, 1938 from off Ningaloo Reef, Western Australia and S. gracilis n. sp. from off Ningaloo Reef, the Great Barrier Reef, Queensland and New Caledonia. Both species exhibit distinct restrictions to certain clades of chaetodontids.     

Geographic divergence in the relationship between Paragobiodon echinocephalus and its obligate coral host

The redhead goby Paragobiodon echinocephalus lives exclusively within the branching coral Stylophora pistillata . While in the Great Barrier Reef fish occupation rate of large coral is higher than that of small coral, an opposite pattern exists in the northern Red Sea. It is suggested that this pattern is caused by a limitation on the adult body size of fish in the northern Red Sea.     

Lek-like spawning,parental care and mating periodicity of the triggerfishPseudobalistes flavimarginatus (Balistidae)

Synopsis The triggerfishPseudobalistes flavimarginatus has a lek-like spawning system at Yonge Reef, Great Barrier Reef. Males migrate to a traditional mating ground where they establish territories enclosing nest sites and egg chambers. Females arrive several days later and choose a male for mating. There is biparental care of the fertilized eggs and a strict division of labour. Females appeared to be confined to the nest site by the male. Mating was semi-lunar: eggs were observed in nests several days before the new and full moons on days when high tide occurred near sunset. Differences were observed in the spawning system of another triggerfish (P. fuscus) between the Great Barrier Reef and the Red Sea. Observations of another triggerfish (Balistoides viridescens) are also reported.     

Spawning of coral reef invertebrates and a second spawning season for scleractinian corals in the central Red Sea

Recent coral spawning observations in the central Red Sea show that most scleractinian species release their gametes in the spring, with a majority of species spawning in April. There is, however, a lack of reproductive data for several other coral species, as well as a general lack of data for other invertebrates. Here, we document the detailed timing of spawning for 13 scleractinian coral species, one sea anemone, and six echinoderms from an inshore reef off the coast of Thuwal, Saudi Arabia, in the spring between April and June 2014. Furthermore, inferred from the presence of mature gametes, we report the month of spawning for three additional coral species in the spring. Seven scleractinian coral species were inferred to release their gametes in a second reproductive season, in the autumn, between September and November. This is the first report of a second spawning season in the Arabian region. Biannual spawning has so far been reported on the Great Barrier Reef, in Western Australia, in Indonesia, in Malaysia, in Palau, in Thailand, in Taiwan, and in Western Samoa.     

STRONG GENETIC DIVERGENCE AMONG POPULATIONS OF A MARINE FISH WITH LIMITED DISPERSAL, ACANTHOCHROMIS POLYACANTHUS, WITHIN THE GREAT BARRIER REEF AND THE CORAL SEA

Abstract Acanthochromis polyacanthus is an unusual tropical marine damselfish that uniquely lacks pelagic larvae and has lost the capacity for broad‐scale dispersal among coral reefs. On the modern Great Barrier Reef (GBR), three color morphs meet and hydridize at two zones of secondary contact. Allozyme electrophoreses revealed strong differences between morphs from the southern zone but few differences between morphs from the northern counterpart, thus suggesting different contact histories. We explore the phylogeography of Acanthochromis polyacanthus with mitochondrial cytochrome b region sequences (alignment of 565 positions) obtained from 126 individuals representing seven to 12 fish from 13 sites distributed over 12 reefs of the GBR and the Coral Sea. The samples revealed three major clades: (1) black fish collected from the southern GBR; (2) bicolored fish collected from the GBR and one reef (Osprey) from the northern Coral Sea; (3) black and white monomorphs collected from six reefs in the Coral Sea. All three clades were well supported (72–100%) by bootstrap analyses. Sequence divergences were very high between the major clades (mean = 7.6%) as well as within them (2.0–3.6%). Within clades, most reefs segregated as monophyletic assemblages. This was revealed both by phylogenetic analyses and AMOVAs that showed that 72–90% of the variance originated from differences among groups, whereas only 5–13% originated within populations. These patterns are discussed in relation to the known geological history of coral reefs of the GBR and the Coral Sea. Finally, we ask whether the monospecific status of Acanthochromis should be revisited because the sequence divergences found among our samples is substantially greater than those recorded among well‐recognized species in other reef fishes.     

An unusual symbiont from the gut of surgeonfishes may be the largest known prokaryote.

Symbionts first reported from the gut of a Red Sea surgeonfish, Acanthurus nigrofuscus (family Acanthuridae), were subsequently described as Epulopiscium fishelsoni. The taxonomic position of this very large (up to 576 microns in length) microorganism has previously been designated in the literature as either uncertain or eukaryotic. We suggest that similar symbionts from Great Barrier Reef surgeonfish may be prokaryotes, which together with E. fishelsoni from the Red Sea may represent the largest known forms of this cell type. Features identifying the symbionts as prokaryotes include the presence of bacterial-type flagella and a bacterial nucleoid and the absence of a nucleus or any other membrane-bound organelle.     

NEW RECORD OF THE MARINE RED ALGA CUBICULOSPORUM (GIGARTINALES) FROM THE SOUTHERN GREAT BARRIER REEF1

Cubiculosporum koronicarpis Kraft (Cubiculosporaceae, Gigartinales), known previously only from the type locality (southeastern Luzon, Philippines), has been collected at North West Island on the southern Great Barrier Reef. The habitat, distribution and taxonomic status of the species are discussed, and habit features of the new specimens are illustrated.     

Genetic diversity of isolated populations of Nautilus pompilius (Mollusca, Cephalopoda) in the Great Barrier Reef and Coral Sea

Nautilus species are the only remaining cephalopods with an external shell. Targeted heavily by the shell trade across their distribution area, these species have a poorly known population structure and genetics. Molecular techniques have been used to assess levels of inter- and intra-population genetic diversity in isolated populations of Nautilus in the northern sections of the Great Barrier Reef (GBR), Australia and in the Coral Sea. Distinct populations, physically separated by depths in excess of 1,000 m were examined. RAPD analysis of genetic differences showed limited differentiation of the “Northern GBR” populations and the “Coral Sea” populations. Discrimination between the two geographic groups was observed from these data. In addition, partial sequencing of the CoxI gene region, yielded 575 bp of sequence, which was aligned for 43 samples and phylogenetic trees constructed to examine genetic relationships. Two distinct clades were resolved in the resulting trees, representing the “Northern GBR” and “Coral Sea” population groups. Inter- and intra-population relationships are presented and discussed. The differentiation of the Nautilus populations from the Northern section of the Great Barrier Reef and those from the Coral Sea were supported by two distinctly different methodologies and the significance of this separation and the potential evolutionary divergence of these two population groups is discussed.     

Historical colonization and demography of the Mediterranean damselfish, Chromis chromis

The desiccation of the Mediterranean Sea during the Messinian Salinity Crisis 6.0-5.3 million years ago (Ma), caused a major extinction of the marine ichthyofauna of the Mediterranean. This was followed by an abrupt replenishment of the Mediterranean from the Atlantic after the opening of the Strait of Gibraltar. In this study, we combined demographic and phylogeographic approaches using mitochondrial and nuclear DNA markers to test the alternative hypotheses of where (Atlantic or Mediterranean) and when (before or after the Messinian Salinity Crisis) speciation occurred in the Mediterranean damselfish, Chromis chromis. The closely related geminate transisthmian pair Chromis multilineata and Chromis atrilobata was used as a way of obtaining an internally calibrated molecular clock. We estimated C. chromis speciation timing both by determining the time of divergence between C. chromis and its Atlantic sister species Chromis limbata (0.93-3.26 Ma depending on the molecular marker used, e.g. 1.23-1.39 Ma for the control region), and by determining the time of coalescence for C. chromis based on mitochondrial control region sequences (0.14-0.21 Ma). The time of speciation of C. chromis was always posterior to the replenishment of the Mediterranean basin, after the Messinian Salinity Crisis. Within the Mediterranean, C. chromis population structure and demographic characteristics revealed a genetic break at the Peloponnese, Greece, with directional and eastbound gene flow between western and eastern groups. The eastern group was found to be more recent and with a faster growing population (coalescent time = 0.09-0.13 Ma, growth = 485.3) than the western group (coalescent time = 0.13-0.20 Ma, growth = 325.6). Our data thus suggested a western origin of C. chromis, most likely within the Mediterranean. Low sea water levels during the glacial periods, the hydrographic regime of the Mediterranean and dispersal restriction during the short pelagic larval phase of C. chromis (18-19 days) have probably played an important role in C. chromis historical colonization.     

The genetic structure of Nautilus pompilius populations surrounding Australia and the Philippines

Understanding the distribution of genetic diversity in exploited species is fundamental to successful conservation. Genetic structure and the degree of gene flow among populations must be assessed to design appropriate strategies to prevent the loss of distinct populations. The cephalopod Nautilus pompilius is fished unsustainably in the Philippines for the ornamental shell trade and has limited legislative protection, despite the species' recent dramatic decline in the region. Here, we use 14 microsatellite markers to evaluate the population structure of N. pompilius around Australia and the Philippines. Despite their relative geographical proximity, Great Barrier Reef individuals are genetically isolated from Osprey Reef and Shark Reef in the Coral Sea (F_ST = 0.312, 0.229, respectively). Conversely, despite the larger geographical distances between the Philippines and west Australian reefs, samples display a small degree of genetic structure (F_ST = 0.015). Demographic scenarios modelled using approximate Bayesian computation analysis indicate that this limited divergence is not due to contemporary gene flow between the Philippines and west Australia. Instead, present‐day genetic similarity can be explained by very limited genetic drift that has occurred due to large average effective population sizes that persisted at both locations following their separation. The lack of connectivity among populations suggests that immigrants from west Australia would not facilitate natural recolonization if Philippine populations were fished to extinction. These data help to rectify the paucity of information on the species' biology currently inhibiting their conservation classification. Understanding population structure can allow us to facilitate sustainable harvesting, thereby preserving the diversity of genetically distinct stocks.     

Coral communities of barrier reefs of Vietnam

The composition and spatial distribution of the coral communities of the barrier reefs of Jiang Bo and of Re Island were described in detail for the first time for Vietnamese waters. Their comparability to the ribbon reefs of the Great Barrier Reef in Australia and to the barrier reefs of the Philippines and Indian Ocean was revealed by morphological parameters, species diversity and zonal distribution. Their geomorphological status, the presence of fore reef, epi-reef and back reef complexes with their specific composition of flora and fauna, and an obligatory lagoon separating the reef from fringing inshore reefs, enabled the attribution of the surveyed reefs to the barrier type of reef.     

Residency and spatial use by reef sharks of an isolated seamount and its implications for conservation

Although marine protected areas (MPAs) are a common conservation strategy, these areas are often designed with little prior knowledge of the spatial behaviour of the species they are designed to protect. Currently, the Coral Sea area and its seamounts (north-east Australia) are under review to determine if MPAs are warranted. The protection of sharks at these seamounts should be an integral component of conservation plans. Therefore, knowledge on the spatial ecology of sharks at the Coral Sea seamounts is essential for the appropriate implementation of management and conservation plans. Acoustic telemetry was used to determine residency, site fidelity and spatial use of three shark species at Osprey Reef: whitetip reef sharks Triaenodon obesus, grey reef sharks Carcharhinus amblyrhynchos and silvertip sharks Carcharhinus albimarginatus. Most individuals showed year round residency at Osprey Reef, although five of the 49 individuals tagged moved to the neighbouring Shark Reef (~14 km away) and one grey reef shark completed a round trip of ~250 km to the Great Barrier Reef. Additionally, individuals of white tip and grey reef sharks showed strong site fidelity to the areas they were tagged, and there was low spatial overlap between groups of sharks tagged at different locations. Spatial use at Osprey Reef by adult sharks is generally restricted to the north-west corner. The high residency and limited spatial use of Osprey Reef suggests that reef sharks would be highly vulnerable to targeted fishing pressure and that MPAs incorporating no-take of sharks would be effective in protecting reef shark populations at Osprey and Shark Reef.