Epibenthie fish larvae in the Great Barrier Reef Lagoon near Lizard Island,Australia

Epibenthic fish larvae near Lizard Island in the Great Barrier Reef Lagoon were sampled with a plankton sled during daylight in November 1981 and January–February 1982. Abundance in the epibenthos was highly variable, and although many types of larvae were present, few were concentrated there relative to the water column. Among those taxa concentrated in the epibenthos, abundances were low and variances were high. Larvae of bregmacerotids, callionymids, clupeids, monacanthids, pinguipedids, platycephalids, pseudochromids, and especially schindleriids, leiognathids and terapontids were concentrated in the epibenthos. Few reef fish larvae were epibenthic. There was some evidence of diel and ontogenetic movements into and out of the epibenthos. Our limited sampling indicates that conventional midwater plankton sampling is adequate for most fish larvae found in the Lizard Island area, but for the larvae of the above ten families, this could produce large underestimates of abundance.     

Evolutionary divergence in common marine ectoparasites Gnathia spp. (Isopoda: Gnathiidae) on the Great Barrier Reef: phylogeography, morphology, and behaviour

The blood‐feeding juvenile stages of gnathiid isopods are important ectoparasites of marine fishes on the Great Barrier Reef (GBR), and are a major component of the diet of cleaner fishes. We report here that these gnathiids have undergone evolutionary diversification, both geographically and temporally (into diurnally and nocturnally active taxa), which has been accompanied by changes in their morphology and behaviour. To perform this analysis, we sequenced a portion of the nuclear ribosomal ITS2 for 47 gnathiids collected from 29 host fishes of 11 species at three locales spanning 2000 km on the GBR. Maximum parsimony and Bayesian phylogenetic analyses both revealed four major clades. There was some degree of geographical structuring in these clades, but there was no evidence supporting host fish specialization, as gnathiids collected from the skin of different teleost taxa did not resolve into distinct clades. The topology of the phylogeny also implied some structuring that was dependent upon collection time (day or night), so we investigated whether there were also behavioural and morphological differences between taxa active at these different times. Nocturnal gnathiids had significantly longer antennules and larger eyes than diurnal gnathiids – two traits presumably adaptive for nocturnal activity. Behavioural tests showed that both nocturnal and diurnal gnathiids use olfaction and vision while foraging, but that nocturnal gnathiids used olfaction more often in dark conditions, and that they were able to perceive movement under extremely low levels of light. Diurnal gnathiids used vision more effectively when there was some ambient light. Our results thus suggest that both phenotypic and genotypic divergence in gnathiids may be influenced by natural selection acting on ecological traits, such as predator avoidance and host detection. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 94 , 569–587.     

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.     

Gnathia gurjanovae sp. n., a new species of Gnathiids (Isopoda: Gnathiidae) from Peter the Great Bay, Sea of Japan

A new species of isopods of the suborder Gnathiidae, Gnathia gurjanovae sp. n. has been described from Peter the Great Bay, Sea of Japan. The new species is most similar to G. derzhavini Gurjanova, 1933, but differs from the latter in a series of morphological characteristics of the male: frontal margin of the head bears a well-pronounced mediofrontal process; each mandible has an unarmed carina and an obscure tooth; pereopod 6 is relatively smooth; the basis, ischium, and merus of pereopod 4 bear strong spurlike processes.     

Modern cryptic microbialite/metazoan facies from Lizard Island (Great Barrier Reef,Australia) formation and concepts

Summary From shallow water caves of fringing reefs related to continental islands of the Lizard Island Section thrombolitic micritic microbialites were observed. The microbialites exhibit always a light decreasing facies succession. The succession starts with a coralgal community and ends with light independent microbial biofilms and benthos (coralline sponges). The sessile mineralized benthos community is constructed of crustose foraminifera, serpulids, thecidean brachiopods, bryozoans, and coralline sponges. The observed benthic community is very similar to those one observed in cryptic habitates of Aptian and Albian reefs of northern Spain. For longtime studies of the microbialite formation and growth rates of coralline sponges the specimens were stained in vivo, within their natural habitat with histochemical fluorochromes and nonfluorescent agents. Main results are a very slow growth of the microbialite and associated sponges (50–100 μm/y). Only few calcifying microbes are participators during microbialite formation. Calcifying acidic organic macromolecules are mainly responsible for microbialite formation by cementing detritical material. Fe/Mn-bacterial biofilms are responsible for strong corrosion of the microbialite. Beside the corrosive activity of the Fe/Mn-bacterial biofilms boring sponges (Aka, Cliona) are the main destructors. Geochemically the observed microbialites are composed of mainly high-Mg calcites and exhibit high positive δ¹³C (+3 to +4) values.     

A new species of Halacarsantia Wolff, 1989 (Crustacea, Isopoda, Asellota, Santiidae) from Wistari Reef, southern Great Barrier Reef, Australia

Halacarsantia acutasp. n. is described from Wistari Reef, Capricorn Group, southern Great Barrier Reef, the first record of the genus from Australia. The new species differs from its congeners in having antenna flagellum composed of 8 articles; epipod apically acute, without setae, broad maxilliped endite and pereopod 1 basis with a short projection. A key to species of the genus is provided.     

Reproductive seasonality,settlement, and post-settlement mortality of Pocillopora damicornis (Linnaeus), at Lizard Island,Great Barrier Reef

Pocillopora damicornis (Linnaeus) has seasonal gametogenesis and planula release at Lizard Island, Great Barrier Reef, in contrast with several previous reports on the species at other locations. The number of planulae released and gonad development varied considerably among colonies sampled at the same time, but reproductive activity occurred predominantly in winter. P. damicornis planulae settled preferentially on algal-covered substrata, rather than bare coral substrata, but showed subsequent mortality inversely related to this settlement preference. Competition with algae and biological disturbance contribute to spat mortality at different stages of settlement and growth.     

A new macradeninine,Zebrasomatrema pichelinae n. g., n. sp. (Digenea: Lecithasteridae), from tangs (Perciformes: Acanthuridae) off the southern Great Barrier Reef,Queensland, Australia

A new genus, Zebrasomatrema, with the type-species Z. pichelinae n. sp., is described from Zebrasoma veliferum at Heron and Lizard Islands, Queensland, Australia, and Z. scopas, Acanthurus lineatus and A. triostegus at Heron Island. The new genus shares with Acanthurotrema an anterior flange, 14 subglobular vitelline lobes, a divided seminal vesicle and a long aglandular duct joining the seminal vesicle and the short pars prostatica, but differs in its quadripartite seminal vesicle, single vitelline field, lack of a sinus-sac and excretory arms which unite in the forebody. This report constitutes the first record of a macradeninine lecithasterid in Australian waters. A key to the Macradenininae is presented.     

Distributional ecology of milkfish,Chanos chanos,larvae in the Great Barrier Reef and Coral Sea near Lizard Island,Australia

Synopsis Plankton hauls captured 682 milkfish larvae (2.1–12.3 mm) in the Great Barrier Reef Lagoon and Coral Sea during 1979–1986. Larvae were present from November to March, and absent in April, July and October. We analyzed concentration, abundance and size-frequency data and concluded that spawning took place in the Coral Sea or at the outer edge of the continental shelf, apparently following an adult spawning migration of at least 50 km. Larvae then moved inshore to at least our most inshore routine sampling site near midshelf. Some larvae may have remained for a period in the lee of reefs along the shelf edge. Larvae apparently occupied the upper few metres of the water column, thereby becoming susceptible to shoreward movement in the wind-driven surface layer. Movement from spawning sites to midshelf probably required active maintenance of vertical position by larvae which enabled passive movement with favourable currents, and perhaps horizontal swimming. By the time larvae reach midshelf, continued inshore movement by horizontal swimming alone is possible.     

<Emphasis Type="Italic">Prodajus curviabdominalis</Emphasis> n. sp. (Isopoda: Epicaridea: Dajidae), an ectoparasite of mysids,with notes on morphological changes,behaviour and life-cycle

Adults and larvae of a new ectoparasitic isopod, Prodajus curviabdominalis n. sp., are described from the mysid Siriella okadai Ii collected from the Seto Inland Sea, western Japan. The adult female is found within the host marsupium with the cephalon directed posteriorly, whereas the dwarf adult male attaches to the ventral surface of the female pleon. The cryptoniscid larva usually attaches to the second or third abdominal somite of the host, using an oral sucker. Mature adults of the new species are distinguished from all other congeners by: pleon of ovigerous female strongly curved dorsally, with large swellings on ventral side; pereon of ovigerous female narrow; exopods on male uropods present; male pleon short and thick. This is the third record of a member of the Dajidae from Japan. The behaviour of the cryptoniscid larvae of the new species on the host mysid was also observed using a video camera. Larvae moved from the first attachment site, usually the second or third abdominal somite of the host mysid, into the marsupium. When host oostegites were not fully developed, larvae entered beneath the host carapace until her marsupium was fully formed. The host infected by a female P. curviabdominalis moved the oostegites rhythmically, an action which may aid the respiration of the parasite.     

Stock Structure, Mortality and Growth of The Decorated Goby, Istigobius decoratus (Gobiidae), at Lizard Island, Great Barrier Reef

Gobiids are an abundant component of coral reef ichthyofauna, yet little is known of their life histories. I examined population structure, mortality and growth of the decorated goby, Istigobius decoratus, a common gobiid of shallow patch reefs on the Great Barrier Reef. Presumed daily increments in sagittal otoliths were used as a proxy for age. The upper age estimate was 266 days suggesting at most an annual life cycle. Instantaneous natural mortality rate estimates were 5.92 year^–1 and 7.92 year^–1 using two estimators, both corresponding to less than 1% annual survivorship. Specimens ranged from 12 to 84 mm total length. Analysis of size-at-age data indicated linear growth at a rate of 0.33 mm day^–1. The linear relationship between size and age meant the population size structure mirrored the age structure with both skewed toward the smallest and youngest classes. High mortality over a 1-year longevity and linear growth suggest high population turnover and, therefore, that I. decoratus and ecologically similar species serve a potentially important role as prey species. This suite of traits is rarely reported for coral reef fishes, which is probably due to the limited attention paid to small-bodied species rather than the rarity of such a life history in these communities.     

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.     

Quantifying Water Flow within Aquatic Ecosystems Using Load Cell Sensors: A Profile of Currents Experienced by Coral Reef Organisms around Lizard Island,Great Barrier Reef,Australia

Current velocity in aquatic environments has major implications for the diversity, abundance and ecology of aquatic organisms, but quantifying these currents has proven difficult. This study utilises a simple and inexpensive instrument (<$150) to provide a detailed current velocity profile of the coral-reef system around Lizard Island (Great Barrier Reef, Australia) at a spatial and temporal scale relevant to the ecology of individual benthos and fish. The instrument uses load-cell sensors to provide a correlation between sensor output and ambient current velocity of 99%. Each instrument is able to continuously record current velocities to >500 cms⁻¹ and wave frequency to >100 Hz over several weeks. Sensor data are registered and processed at 16 MHz and 10 bit resolution, with a measuring precision of 0.06±0.04%, and accuracy of 0.51±0.65% (mean ±S.D.). Each instrument is also pressure rated to 120 m and shear stresses ≤20 kNm⁻² allowing deployment in harsh environments.The instrument was deployed across 27 coral reef sites covering the crest (3 m), mid-slope (6 m) and deep-slope (9 m depth) of habitats directly exposed, oblique or sheltered from prevailing winds. Measurements demonstrate that currents over the reef slope and crest varies immensely depending on depth and exposure: Currents differ up to 9-fold within habitats only separated by 3 m depth and 15-fold between exposed, oblique and sheltered habitats. Comparisons to ambient weather conditions reveal that currents around Lizard Island are largely wind driven. Zero to 22.5 knot winds correspond directly to currents of 0 to >82 cms⁻¹, while tidal currents rarely exceed 5.5 cms⁻¹. Rather, current velocity increases exponentially as a function of wave height (0 to 1.6 m) and frequency (0.54 to 0.20 Hz), emphasizing the enormous effect of wind and waves on organisms in these shallow coral reef habitats.     

Overstreetia olsoni n. sp. (Digenea: Zoogonidae) from the Capricorn silverside Atherinomorus capricornensis (Woodland) (Atherinidae) off Heron Island, southern Great Barrier Reef

A new species, Overstreetia olsoni, is described from Atherinomorus capricornensis off Heron Island on the Great Barrier Reef off Queensland, Australia. It differs from its only known congener in that the enlarged spines of the circum-oral rows are smaller ( ≤ 4.5 × 3.5 vs ≤ 21.5 × 10.5μm), the sucker-ratio is smaller (1: 0.97–1.01 vs 1:1.8) and the eggs are larger (40–45 × 22–28 vs 34–37 × 17–22μm).     

Symbiodinium (Dinophyceae) diversity in reef‐invertebrates along an offshore to inshore reef gradient near Lizard Island,Great Barrier Reef

Despite extensive work on the genetic diversity of reef invertebrate‐dinoflagellate symbioses on the Great Barrier Reef (GBR; Australia), large information gaps exist from northern and inshore regions. Therefore, a broad survey was done comparing the community of inshore, mid‐shelf and outer reefs at the latitude of Lizard Island. Symbiodinium (Freudenthal) diversity was characterized using denaturing gradient gel electrophoresis fingerprinting and sequencing of the ITS2 region of the ribosomal DNA. Thirty‐nine distinct Symbiodinium types were identified from four subgeneric clades (B, C, D, and G). Several Symbiodinium types originally characterized from the Indian Ocean were discovered as well as eight novel types (C1kk, C1LL, C3nn, C26b, C161a, C162, C165, C166). Multivariate analyses on the Symbiodinium species diversity data showed a strong link with host identity, consistent with previous findings. Of the four environmental variables tested, mean austral winter sea surface temperature (SST) influenced Symbiodinium distribution across shelves most significantly. A similar result was found when the analysis was performed on Symbiodinium diversity data of genera with an open symbiont transmission mode separately with chl a and PAR explaining additional variation. This study underscores the importance of SST and water quality related variables as factors driving Symbiodinium distribution on cross‐shelf scales. Furthermore, this study expands our knowledge on Symbiodinium species diversity, ecological partitioning (including host‐specificity) and geographic ranges across the GBR. The accelerating rate of environmental change experienced by coral reef ecosystems emphasizes the need to comprehend the full complexity of cnidarian symbioses, including the biotic and abiotic factors that shape their current distributions.     

Preptetos cannoni n. sp. (Digenea: Lepocreadiidae) from Siganus lineatus (Teleostei: Siganidae) from the southern Great Barrier Reef,Australia

Preptetos cannoni n. sp. is described from Siganus lineatus from Heron Island on the southern Great Barrier Reef, Australia. Morphological features that are diagnostic of this species include: a genital pore that is sinistral to the ventral sucker and vitelline follicles that reach anteriorly to at least the bifurcation of the intestine. This is the first report of a species of the genus Preptetos from Australian waters and from fishes of the genus Siganus.