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Many species of seabird ingest or are provisioned with pumice stones, buoyant volcanic rocks that are thought to aide in digestion, occasionally during times of poor prey availability. Unlike other indigestible matter, like plastics, the effect of pumice on chick growth, its relationship with ingested plastics, and variation among years has not yet been examined. We analysed the amount of ingested pumice from 739 Flesh-footed (Ardenna carneipes) and 173 Wedge-tailed Shearwaters (A. pacifica) from Lord Howe Island, Australia sampled using stomach lavage between 2011 and 2022. The total mass of ingested pumice was positively related to the mass of ingested plastics in Flesh-footed, but not Wedge-tailed Shearwaters, but not when using mean stone mass. Pumice mass did not vary over time, except for one higher year for each species (2016 for Flesh-footed Shearwaters and 2014 for Wedge-tailed Shearwaters), and there was no effect of pumice mass on chick body size at fledgling. Our results are consistent with the coexistence over geological time of seabirds and floating pumice, and future work should focus on aspects of retention in the digestive system and potential interactions with and efficacy in the presence of novel materials, like plastics. [ABSTRACT FROM AUTHOR]

Understanding the dynamics of population recovery is particularly complex when an organism has multiple, remote breeding and feeding grounds separated by one of the longest known migration routes. This study reports on the most comprehensive assessment of humpback whale ( Megaptera novaeangliae) movements between remote Antarctic waters south of New Zealand and east Australia (EA), and the migratory corridors and breeding grounds of Australia and Oceania. A total of 112 individual whales were identified; 57 from microsatellites and 61 by fluke with 23 % ( n = 26) matched to sites outside Antarctica. Despite large datasets from other southern regions being included in the comparison, the whales were predominantly linked to EA ( n = 24). Only two matches to the Oceania catalogues directly north was surprising; therefore the primary feeding grounds of these endangered whales still remain unknown. The confirmation of the Balleny Islands as an important feeding ground for EA whales could provide an insight into reasons behind the rapid recovery of this population. Determining the feeding grounds of Oceania's whales may explain whether prey energetics or migration length are limiting factors to their recovery and will allow an understanding of future ecosystem changes in these whales. [ABSTRACT FROM AUTHOR]

To understand habitat requirements of green turtles in an important foraging area subject to both anthropogenic and natural perturbations, we examined residency, home range and habitat use of juvenile, sub-adult and adult green turtles (Chelonia mydas) in Port Curtis, Australia, using passive acoustic telemetry. Acoustic tags were attached to turtles at Pelican Banks (n = 33) and Wiggins Island (n = 16). Between May 2013 and September 2014, tagged turtles were detected > 1.3 million times by 46 acoustic receivers. Data demonstrated variability in residence index and home range size between Pelican Banks and Wiggins Island that was largely attributed to larger body size at Pelican Banks and habitat differences. Tide had a significant influence of movement and habitat use. At Pelican Banks turtles moved into intertidal seagrass beds at high tide and retreated to the channel at low tide. At Wiggins Island, high tide 50% KUD area was more than double low tide area and turtles moved into the mangroves at high tide and retreated to channels at low tide. Diet reflected availability of food resources; seagrass dominated diet at Pelican Banks whereas epiphytic red algae dominated diet at Wiggins Island. There was no evidence of a diurnal shift in home range or habitat use. The use of intertidal areas by both turtles and small recreational craft during high tide at Pelican Banks resulted in increased risk of vessel strike. Unusually short residency at Pelican Banks suggested that animals had either relocated to another foraging area or a combination of recent flooding, port development and reduced seagrass coverage during the period of monitoring resulted in higher emigration rates than previously demonstrated for this species. Acoustic telemetry is a valuable tool for obtaining fine-scale, long- term data on movement and residency of green turtles. [ABSTRACT FROM AUTHOR]

Crown-of-thorns starfish (Acanthaster spp.) is reported to have exceptional reproductive capacity, but this has been largely inferred based on the overall weight of gonads (and mostly for females), and there are limited estimates of the concentration of gametes within gametogenic tissues. This study quantified gamete concentrations for both male and female Pacific crown-of-thorns starfish (Acanthaster cf. solaris), collected on Australia's Great Barrier Reef in 2014–2019. Gamete concentrations varied greatly among female starfish (12,338–133,810 oocytes g−1), such that the estimated reproductive capacity ranged from < 1000 oocytes for the smallest (141 mm) individual up to 106 million oocytes for a 480-mm diameter female. Gamete concentrations were much more conserved for male starfish, and did not vary with size. Nonetheless, the total mass of gametogenic tissue increased with size, and fecundity of large males > 400-mm diameter approached 53 billion sperm. This study reaffirms that crown-of-thorns starfish have exceptional reproductive capacity, which is strongly size-dependent, but also varies greatly among individuals. Importantly, individual variation in reproductive output may be important in understanding for population irruptions of Acanthaster spp., and their concomitant effects on reef ecosystems. [ABSTRACT FROM AUTHOR]

Inferences regarding animal presence from passive acoustic receiver arrays are driven by the spatial configuration of receivers. Large, dense arrays provide more information, but maintenance of multiple receivers is costly. Configuring acoustic receiver arrays to maximise coverage while minimising cost is therefore paramount. This study used data from a dense acoustic receiver array within a white shark Carcharodon carcharias nursery area on the east coast of Australia to assess how detection data of tagged white sharks in the area was affected by reducing the array size. Receivers were sub-sampled post hoc by simple random sampling, clustered random sampling, and sampling of the top performing receivers. Using the top performing receivers, array size could be reduced by 60% (10 out of 25 receivers) while still detecting a median of 100% of white sharks detected with the full array. With random and clustered sampling methods, a 40% reduction in array size (15 out of 25 receivers) detected a median of 100% of sharks. Reducing the array size by 60% using the top performing receivers resulted in a 35% decrease in the median number of detections per visit of the tagged sharks (67 out of 102.5 detections). In comparison, reducing the array by the same amount with random and clustered sampling methods resulted in a 57% decrease (44 out of 102.5 detections). The post hoc sampling methods used in this study are an empirical approach for optimising placement of limited receiver resources with broad application for establishing cost-effective monitoring. [ABSTRACT FROM AUTHOR]

Pelagic biofoulers such as barnacles or bryozoans settle and raft on natural debris like pumice or seeds. Recent influxes of marine debris into the world's oceans, especially plastic, have increased habitat availability for these biofoulers. Goose barnacles in the genus Lepas are some of the most common biofouling taxa globally, and play an important role in biofouling communities as foundation species. We examined community succession, growth rates and isotopic composition in Lepas and their associated biofouling communities in coastal waters of eastern Australia. Community succession on a fixed surface mooring showed an increase in species diversity over 25 weeks. Using the abundances of L. anserifera, L. anatifera, and the amphipods Caprella danilevskii and Jassa slatteryi, we created an equation to estimate minimum duration at sea. Predators such as the polychaete Amphinome rostrata may influence the biofouling community, as can beach scavengers once floating debris is cast ashore. We report a new maximum growth rate for L. anserifera of 1.45 mm−1, and our study is the first to report growth rates for any species of Lepas faster than 1 mm day−1. Lepas were larger on moored floats than on smaller, free-floating drifters. δ18O content of Lepas shells was a robust predictor of sea surface temperatures during formation for L. anatifera and L. anserifera. Our findings have important applications for estimating drift duration and trajectories of marine debris. [ABSTRACT FROM AUTHOR]

Ecology of many sea cucumbers, including the world's heaviest holothuroid Thelenota anax, remains understudied, hindering effective fisheries management and conservation. We located, measured and weighed 38 T. anax over 10 days at Lizard Island, northeast Australia. Body length alone was a suitable predictor of body weight for this species. Short-term (1–4 h) rates of displacement and sediment defecation were measured on 30 animals across three sites. The animals were highly mobile, moving, on average, 57 cm h−1 (± 11 SE), and reworking 34 g dry weight of sediment h−1 (± 7 SE). The animals moved more and defecated more sediments in areas where surrounding sediments had lower levels of organic matter. Defecation rates increased through daytime hours. The high mobility of T. anax should confer an advantage for mate-finding but also could increase spillover from small marine reserves into fishing grounds. Our findings galvanise a pattern of high mobility in larger holothuroids and show that food resources and time of day modulate the extent of sediment reworking by deposit feeding holothuroids. The high sediment turnover rate highlights the detrimental effect that overfishing of these large holothuroids will have on the health of coastal marine ecosystems. [ABSTRACT FROM AUTHOR]

The establishment of protected corridors linking the breeding and foraging grounds of many migratory species remains deficient, particularly in the world's oceans. For example, Australia has recently established a network of Commonwealth Marine Reserves, supplementing existing State reserves, to protect a wide range of resident and migratory marine species; however, the routes used by mobile species to access these sites are often unknown. The flatback marine turtle ( Natator depressus) is endemic to the continental shelf of Australia, yet information is not available about how this species uses the marine area. We used a geospatial approach to delineate a coastal corridor from 73 adult female flatback postnesting migratory tracks from four rookeries along the north-west coast of Australia. A core corridor of 1,150 km length and 30,800 km area was defined, of which 52 % fell within 11 reserves, leaving 48 % (of equivalent size to several Commonwealth Reserves) of the corridor outside of the reserve network. Despite limited data being available for other marine wildlife in this region, humpback whale migratory tracks overlapped with 96 % of the core corridor, while the tracks of three other species overlapped by 5-10 % (blue whales, olive ridley turtles, whale sharks). The overlap in the distribution ranges of at least 20 other marine vertebrates (dugong, cetaceans, marine turtles, sea snakes, crocodiles, sharks) with the corridor also imply potential use. In conclusion, this study provides valuable information towards proposing new locations requiring protection, as well as identifying high-priority network linkages between existing marine protected areas. [ABSTRACT FROM AUTHOR]

The thermal envelope of development to the larval stage of two echinoids from eastern Australia was characterized to determine whether they fill their potential latitudinal ranges as indicated by tolerance limits. The tropical sand dollar, Arachnoides placenta, a species that is not known to have shifted its range, was investigated in Townsville, northern Australia (19°20′S, 146°77′E), during its autumn spawning season (May 2012). The subtropical/temperate sea urchin, Centrostephanus rodgersii, a species that has undergone poleward range expansion, was investigated in Sydney, southern Australia (33°58′S, 151°14′E), during its winter spawning season (August 2012). The thermal tolerance of development was determined in embryos and larvae reared at twelve temperatures. For A. placenta, the ambient water temperature near Townsville and experimental control were 24 °C and treatments ranged from 14 to 37 °C. For C. rodgersii, ambient Sydney water temperature and experimental control were 17 °C, and the treatment range was 9-31 °C. A. placenta had a broader developmental thermal envelope (14 °C range 17-31 °C) than C. rodgersii (9 °C range 13-22 °C). Both species developed successfully at temperatures well below ambient, suggesting that cooler water is not a barrier to poleward migration for either species. Both species presently live near the upper thermal limits for larval development, and future ocean warming could lead to contractions of their northern range limits. This study provides insights into the factors influencing the realized and potential distribution of planktonic life stages and changes to adult distribution in response to global change. [ABSTRACT FROM AUTHOR]

The attraction or provisioning of sharks for the purpose of tourism is a lucrative and popular industry that remains controversial regarding its possible risks to target species and impacts on local ecosystems. The long-term impacts of such activities on the behaviour and movement patterns of sharks have typically been difficult to establish as most studies investigate contemporary behaviour concurrent with existing operations and thus have no comparative base from which to compare effects. We compared patterns of residency and behaviour of acoustic-tagged white sharks at the Neptune Islands in South Australia between periods before and after an abrupt and sustained doubling of cage-diving effort that occurred in 2007. The number of sharks reported by cage-dive operators significantly increased after 2007. Comparisons also revealed there were significant increases in sharks' periods of residency, the periods spent within areas where shark cage-diving operations occur and changes in sharks' diel pattern of habitat use. Changes were site-specific with no significant differences in shark behaviour revealed over the same period at an island group 12 km from regular shark cage-dive sites. The results suggest that cage-diving operations can lead to long-term changes in the site-specific behaviour of a highly vagile shark species which may need to be considered in the context of their conservation and in managing the impacts of the industry. [ABSTRACT FROM AUTHOR]

Rates and direction of movement in the sand dollar Peronella lesueuri were measured in summer and winter in Cockburn Sound, a large coastal embayment in south-western Australia. P. lesueuri was found to have a diurnal activity pattern throughout the year and had a greater movement rate in the summer (mean of 5.3 cm h, day; 3.9 cm h, night) than in the winter (mean of 2.7 cm h, day; 2.0 cm h, night). Seasonal change in temperature and physiological requirements by the sand dollar are the most likely reason for the seasonal differences. Reasons for diurnal variation were not clear. Direction of movement was found to be random at both times of the year. Based on these movement rates, one sand dollar can bioturbate an approximate area of 0.1 m day and 36.4 m year. At a conservative density estimate of 0.5 sand dollars per m it takes approximately 20 days for the sand dollars to rework the entire area of the sediments in the habitats they occupy. [ABSTRACT FROM AUTHOR]

Regions of high primary production along the oligotrophic west coast of Australia between 34 and 22°S in May-June 2007 (midway through the annual phytoplankton bloom) were found around mesoscale features of the Leeuwin Current. At 31°S, an anticyclonic eddy-forming meander of the Leeuwin Current had a mixed layer depth of >160 m, a depth-integrated chlorophyll a (Chl a)-normalised primary production of 24 mg C mg Chl a day compared to the surrounding values of <18 mg C mg Chl a day. In the north between 27 and 24°S, there were several stations in >1,000 m of water with a shallow (<100 m) and relatively thin layer of high nitrate below the mixed layer but within the euphotic zone. These stations had high primary production at depths of ~100 m (up to 7.5 mg C m day) with very high rates of production per unit Chl a (up to 150 mg C mg Chl a day). At 27-24°S, the majority of the phytoplankton community was the ubiquitous tropical picoplankters, Synechococcus and Prochlorococcus. There was a decline in the dominance of the picoplankters and a shift towards a more diverse community with more diatoms, chlorophytes, prasinophytes and cryptophytes at stations with elevated production. Photosynthetic dinoflagellates were negligible, but heterotrophic dinoflagellate taxa were common. Haptophytes and pelagophytes were also common, but seemed to contribute little to the geographical variation in primary production. The mesoscale features in the Leeuwin Current may have enhanced horizontal exchange and vertical mixing, which introduced nitrate into the euphotic zone, increasing primary production and causing a shift in phytoplankton community composition in association with the annual winter bloom. [ABSTRACT FROM AUTHOR]

Key biological processes such as the timing and synchrony of reproduction, are sensitive to fluctuations in the environment, as well as alterations in the physiology and behaviour of individuals and the ecology of populations. The main aim of this study was to identify patterns in reproductive timing and relationships with prevailing environmental conditions, for the major habitat-forming alga in temperate Australia, Ecklonia radiata (C. Agardh) J. Agardh. We observed strong synchronous patterns of zoospore production across spatial scales from hundreds of metres to tens of kilometres, with populations of E. radiata reproducing from mid-summer to the end of autumn. High zoospore densities were positively related to sea temperature and E. radiata released zoospores in temperatures well above previously documented thermal tolerance limits for other Laminariales. Reproductive timing was also negatively related to seasonal increase in wave exposure. We conclude that E. radiata undergoes synchronous reproduction which can be linked to its annual growth cycle and natural environmental fluctuations, to promote growth and survival of recruits. [ABSTRACT FROM AUTHOR]

Understanding patterns in site fidelity is important for defining the ecological role of species in the systems they use and for gauging the effects of human impacts on their populations. We analyzed long-term movement data of adult spottail sharks ( Carcharhinus sorrah) in Cleveland Bay, Australia, to define the degree of site fidelity this species shows to coastal areas. Individuals were monitored in the study site for 28-566 days, and residency index (i.e., proportion of days present to total monitoring period) ranged from 0.08 to 0.95. Using a randomization procedure, we determined that the movement paths for 90 % of individuals (11 female and 7 male) were more constrained than random, with individuals exhibiting a high degree of site fidelity to consistent areas within the study site. Examining distances moved revealed that individuals used the same areas repeatedly and remained in close proximity (i.e., <6 km) to their location of first detection. While some individuals consistently used and returned back to the same locations, low residency among others suggests that a portion of the population may roam more widely. Long-term site fidelity to consistent areas may be a successful behavioral strategy for C. sorrah by increasing individual fitness through spatial familiarity and knowledge of resources. [ABSTRACT FROM AUTHOR]

We studied the diel variation of in situ coral temperature, irradiance and photosynthetic performance of hemispherical colonies of Porites lobata and branching colonies of Porites cylindrica during different bulk water temperature and tidal scenarios on the shallow reef flat of Heron Island, Great Barrier Reef, Australia. Our study presents in situ evidence that coral tissue surface temperatures can exceed that of the surrounding water under environmental conditions typically occurring during low tide in shallow reef or lagoon environments. Such heating may be a regular occurrence on shallow reef flats, triggered by the combined effects of high irradiance and low water flow characteristic of low Spring tides. At these times, solar heating of corals coincides with times of maximum water temperature and high irradiance, where the slow flow and consequent thick boundary layers impede heat exchange between corals and the surrounding water. Despite similar light-absorbing properties, the heating effect was more pronounced for the hemispherical P. lobata than for the branching P. cylindrica. This is consistent with previous laboratory experiments showing the evidence of interspecific variation in coral thermal environment and may result from morphologically influenced variation in convective heat transfer and/or thermal properties of the skeleton. Maximum coral surface warming did not coincide with maximum irradiance, but with maximum water temperature, well into the low-tide period with extremely low water flow in the partially drained reef flat, just prior to flushing by the rising tide. The timing of low tide thus influences the thermal exposure and photophysiological performance of corals, and the timing of tidally driven coral surface warming could potentially have different physiological impacts in the morning or in the afternoon. [ABSTRACT FROM AUTHOR]

Investigating predator-prey relationships is an important component for identifying and understanding the factors that influence the structure and function of ecosystems. Mesopredators, defined as mid-level predators, have a profound effect on ecosystem structure by contributing an important link between apex predators and lower trophic levels. The diet of two elasmobranch mesopredators, Squalus acanthias and Mustelus antarcticus, was investigated in three locations in south-east Tasmania. Squalus acanthias consumed predominantly pelagic teleosts and cephalopods, while M. antarcticus predominantly consumed benthic crustaceans. As a result, there was low dietary and niche overlap between the two species. There was however evidence of intra-specific dietary variations between locations for both the species. This study has contributed to a better understanding of the top-down dynamics of the food web in coastal Tasmania, by providing important dietary information of two abundant mesopredators. In addition, the similar dietary patterns for S. acanthias and other Mustelus species over much of their global range suggest they may be consistent in their trophic roles across systems, with limited competition between these two sympatric mesopredators to be expected. [ABSTRACT FROM AUTHOR]

Territorial damselfishes that manipulate ('farm') the algae in their territories can have a marked effect on benthic community structure and may influence coral recovery following disturbances. Despite the numerical dominance of farming species on many reefs, the importance of their grazing activities is often overlooked, with most studies only examining their roles over restricted spatial and temporal scales. We used the results of field surveys covering 9.5° of latitude of the Great Barrier Reef to describe the distribution, abundance and temporal dynamics of farmer communities. Redundancy analysis revealed unique subregional assemblages of farming species that were shaped by the combined effects of shelf position and, to a lesser extent, by latitude. These spatial patterns were largely stable through time, except when major disturbances altered the benthic community. Such disturbances affected the functional guilds of farmers in different ways. Since different guilds of farmers modify benthic community structure and affect survival of juvenile corals in different ways, these results have important implications for coral recovery following disturbances. [ABSTRACT FROM AUTHOR]

Parvulastra exigua, a species that lacks a dispersive larva, is paradoxically one of the most widely distributed and abundant sea stars in Australia. The potential that self-fertilization and successful development of self-generated progeny might contribute to population maintenance in this species was investigated through induction of spawning in isolated individuals collected from five populations near Sydney, New South Wales (34°S, 151°E), during the spawning period (August-October 2010, 2011). Evidence of selfing differed significantly among the five populations but the level of selfing within individual egg masses did not. Overall, there was a mean of 8.9% fertilization in egg masses with embryos. Some clutches developed to the juvenile stage while others arrested development before hatching. The presence of miniscule testis tissue in gonads that appeared to be ovaries indicated that hermaphroditism may be more common in some populations than indicated by anatomy. Mixed mating (selfing + outcrossing), pseudocopulation during egg laying and developmental success of self-fertilized embryos may contribute to the ecological success of P. exigua. These might influence population genetic structure and would facilitate establishment of founder populations by a small number of migrants. [ABSTRACT FROM AUTHOR]

The composition and functionality of ecologically important herbivorous fish assemblages were examined throughout much of Australia's Great Barrier Reef (GBR). Diversity and abundance of surgeonfishes (Acanthuridae), parrotfishes (Labridae) and rabbitfishes (Siganidae) were strongly associated with position on the continental shelf, whilst effects of latitude were weaker and inconsistent. Species distributions varied considerably amongst taxonomic groups; parrotfishes were mostly widespread whilst distributions of surgeonfishes were often restricted. Most inshore environments supported depauperate herbivore assemblages dominated by different taxa and functional groups compared with assemblages in offshore environments. There were also strong cross-shelf transitions in the main taxa performing each functional role. Overall, this study show that the functional contributions of herbivorous fish assemblages to important ecosystem processes and the contributing taxa vary considerably amongst different GBR environments. Additionally, the two most numerically dominant herbivores actively select detritus, not algae, supporting increasing evidence for the importance of detritus in coral reef ecology. [ABSTRACT FROM AUTHOR]

Patterns of community development on subtidal rocky reefs in Marmion Lagoon, southwest Australia, were investigated with a settlement panel experiment. We tested the hypothesis that community development would differ between outer and inner reefs lines, because exposure to swell and wave energy was significantly greater on outer reefs. Following a 14-month deployment, we recorded pronounced variability between panels and sites, but did not detect any effect of wave exposure on the structure of panel assemblages. Subsequent data exploration suggested the importance of the presence of kelp recruits ( Ecklonia radiata) in structuring the overall assemblage. Panel assemblages with kelp recruits were significantly different in structure to those without, principally because of greater space coverage of encrusting coralline algae and less coverage of red turfing algae, spirorbids, and bryozoans. Mature E. radiata act as ecosystem engineers in subtidal rocky reefs in southwest Australia. Our results suggested the importance of young, recruiting kelps in determining patterns of early community development on newly available hard substrata. [ABSTRACT FROM AUTHOR]

nimal movement is a pivotal element of many ecological processes, and on ocean-exposed sandy shores, ghost crabs (genus Ocypode) undertake extensive nocturnal forays on the beach surface. Because crab populations are also threatened by vehicle traffic, indicators that can detect sublethal effects before population declines are manifest are important. To this end, we tested on a barrier island in Eastern Australia whether movement patterns of crabs respond predictably to disturbance by vehicles; this was done by tracking (using the spool-and-line technique) crabs at night in beach sections open and closed to traffic. Beach traffic not only halved population densities of crabs on the unvegetated beach seawards of the dunes, but it also fundamentally changed crab behaviour and movement: individuals from beach areas rutted by tyre tracks travelled shorter distances in a more erratic zigzag pattern, and they had significantly compressed home ranges. Such behavioural changes linked to human pressures could be well suited as an early warning signal for wider negative ecological impacts (as demonstrated by reduced abundances). They also emphasize the need to incorporate sublethal effects into the assessment and management of ecological changes resulting from beach recreation. [ABSTRACT FROM AUTHOR]

We examined the feeding ecology and niche segregation of the ten most abundant fish species caught by longline operations off eastern Australia between 1992 and 2006. Diets of 3,562 individuals were examined. Hook timer data were collected from a further 328 fish to examine feeding behaviour in relation to depth and time of day. Prey biomass was significantly related to predator species, predator length and year and latitude of capture. Although the fish examined fed on a mix of fish, squid and crustacea, fish dominated the diet of all species except small albacore ( Thunnus alalunga) which fed mainly on crustacea and large swordfish ( Xiphias gladius) and albacore which fed mainly on squid. Cannibalism was observed in lancetfish ( Alepisaurus spp.). Multidimensional scaling identified three species groups based on their diet composition. One group consisted of yellowfin tuna ( T. albacares), striped marlin ( Tetrapturus audax) and dolphinfish ( Coryphaena hippurus); a second group consisted of bigeye tuna ( T. obesus), swordfish and albacore; and a third consisted of southern bluefin tuna ( T. maccoyii) and blue shark ( Prionace glauca). Of note was the separation of mako shark ( Isurus oxyrhynchus) and lancetfish from all other predators. Prey length generally increased with increasing predator length although even large predators fed on a wide range of prey lengths including very small prey. Overall, differences in prey type and size, feeding times and depths were noted across the range of species examined to the extent that predators with overlapping prey, either in type or size, fed at different times of the diel period or at different depths. Taken together these data provide evidence for feeding niche segregation across the range of oceanic top predators examined. [ABSTRACT FROM AUTHOR]

The composition of lipids and fatty acids was determined for the livers, muscle, pancreas, kidney and stomach fluids of deepwater chondrichthyan species (including 11 squaliformes, 3 chimaeriformes, 1 hexanchiforme and 3 carcharhiniformes) caught as bycatch from continental waters off south-eastern Australia. The lipid class, fatty acid and fatty alcohol composition differed markedly in each tissue and in each species. The lipid and fatty acid composition of large, lipid-rich (38–70% wet weight, ww) livers demonstrated the multifunctional role of this organ in: lipid distribution, storage and biosynthesis, and buoyancy regulation. In the liver, the importance of certain lipids (including squalene, diacylglyceryl ethers, triacylglycerols and to a lesser extent wax esters) as mediators of buoyancy varied according to lifestyle and habitat. Less variability was observed in the muscle profiles, characterized by low lipid content (<1.0% ww) and high relative levels of polar lipids (>70%). The lipid and fatty acid profiles of the kidney and pancreas showed the highest intraspecific variability, suggesting these organs also have complex roles in lipid storage and metabolism. Overall intra- and interspecific differences in the tissue fatty acid profiles could be related to differences in a number of factors including phylogeny, habitat (depth), buoyancy regulation and diet and presumably also reflect different ecological roles. The lipid and fatty acid profiles are the first published for Rhinochimaera pacifica, Chimaera lignaria and Figaro boardmani and the first to demonstrate interspecific variation in lipid profiles of various tissues of deepwater chondrichthyans. The application of multivariate analysis to lipid class and fatty acid tissue profiles in chondrichthyans inferred dietary differences and metabolic preferences between species and habitats. These results have important implications for the future use of fatty acids as dietary tracers in chondrichthyan research. [ABSTRACT FROM AUTHOR]

Satellite telemetry was used to study the movements and behaviour of ten blue sharks and one individual each of shortfin mako, thresher and bigeye thresher off eastern Australia. The tracks showed latitudinal movements of up to 1,900 km, but none of the sharks travelled away from the eastern Australian region. Tracking periods did not exceed 177 days. All species showed oscillatory dive behaviour between the surface layers to as deep as 560–1,000 m. Blue sharks spent 35–58% of their time in <50 m depths and 10–16% of their time in >300 m. Of these four species, the bigeye thresher spent the least time in the surface layers and the most time at >300 m depth. All four species showed clear diel behaviour generally occupying shallower depths at night than during the day. Blue sharks were mainly in 17.5–20.0°C water, while the thresher sharks showed a more bimodal temperature distribution. [ABSTRACT FROM AUTHOR]

Five polymorphic microsatellite loci were developed and then used to assess the population genetic structure of a commercially harvested merobenthic octopus species ( Octopus maorum) in south-east Australian and New Zealand (NZ) waters. Beak and stylet morphometrics were also used to assess population differentiation in conjunction with the genetic data. Genetic variation across all loci and all sampled populations was very high (mean number alleles = 15, mean expected heterozygosity = 0.85). Microsatellites revealed significant genetic structuring (overall FST = 0.024, p < 0.001), which did not fit an isolation-by-distance model of population differentiation. Divergence was observed between Australian and NZ populations, between South Australia and north-east Tasmania, and between two relatively proximate Tasmanian sites. South Australian and southern Tasmanian populations were genetically homogeneous, indicating a level of connectivity on a scale of 1,500 km. Morphometric data also indicated significant differences between Australian and NZ populations. The patterns of population structuring identified can be explained largely in relation to regional oceanographic features. [ABSTRACT FROM AUTHOR]

Climate change is a major threat to coral reef ecosystems worldwide. A key determinant of the fate of reef corals in a warming climate is their capacity to tolerate increasing thermal stress. Here, an increase in thermal tolerance is demonstrated for three major coral genera ( Acropora, Pocillopora and Porites) following the extensive mass bleaching event that occurred on the Great Barrier Reef (Australia) in 1998. During the subsequent and more severe thermal stress event in 2002, bleaching severity was 30–100% lower than predicted from the relationship between severity and thermal stress in 1998, despite higher solar irradiances during the 2002 thermal event. Coral genera most susceptible to thermal stress ( Pocillopora and Acropora) showed the greatest increase in tolerance. Although bleaching was severe in 1998, whole-colony mortality was low at most study sites. Therefore, observed increases in thermal tolerance cannot be explained by selective mortality alone, suggesting a capacity for acclimatization or adaptation. Although the vulnerability of coral reefs remains largely dependent on the rate and extent of climate change, such increase in thermal tolerance may delay the onset of mass coral mortalities in time for the implementation of low-emission scenarios and effective management. [ABSTRACT FROM AUTHOR]

Sea anemones that host obligate symbiotic anemonefish are ecologically important throughout many coral reef regions of the Indo-Pacific. This study provides the first quantitative data on larval settlement rates and juvenile development of two species of host sea anemone, Heteractis crispa and Entacmaea quadricolor. Larvae were reared from broadcast spawned gametes of sexually reproductive male and female anemones collected from the Solitary Islands Marine Park, NSW, Australia. Prior to the start of the experiments, H. crispa larvae were reared for 3 days after spawning in March 2004 and E. quadricolor larvae were reared for 4 days after spawning in February 2005. Larval settlement onto biologically conditioned terracotta tiles in outdoor flow-through seawater aquaria was first recorded 4 days after spawning for H. crispa and 5 days after spawning for E. quadricolor. Peak settlement occurred 10 days after spawning, with a mean of 33.4 and 50.3% of the original groups of 350 larvae in replicate tanks settling for H. crispa and E. quadricolor, respectively. Tentacles arose as outpocketings of the oral region, at first appearing as small rounded buds. These buds elongated to form long, thin, tapering tentacles in H. crispa, whereas E. quadricolor tentacles had slight bulbs below the tips. Juvenile anemones, especially H. crispa, were found to have very different colouration and markings when compared with adult anemones, and therefore the descriptions and images provided here will enable correct identification of juvenile recruits. [ABSTRACT FROM AUTHOR]

The endofaunal assemblages associated with two species of sponge from the family Chalinidae ( Haliclona sp. 1 and Haliclona sp. 2) were studied at four locations along the south west coast of Australia. The species have distinct morphologies and inhabit similar microhabitats; there is also considerable scientific interest in Haliclona sp. 1 (green Haliclona) due to the unique bioactive compound it produces. A total of 948 and 287 endofaunal individuals were found associated with 16 specimens of both the green Haliclona and Haliclona sp. 2 (brown Haliclona), respectively. Twenty-four endofaunal taxa were found (from mysid shrimps to teleost fish), with the brown Haliclona having a greater density of endofaunal species and individuals than the green Haliclona. The endofaunal assemblages of both species of sponge were significantly different, but only the endofaunal assemblage within the green Haliclona differed significantly among locations. Differences in the abundance and biomass of associated endofauna of each species of sponge can be related to differences in their morphologies, size and internal structure. In the green Haliclona, differences in endofaunal assemblages among locations are unlikely to be due to environmental influences as taxa discriminating each locations assemblage were common to both species of sponge. Numerous endofaunal individuals were found to be reproductively active, and it is clear that the species of sponge provide important habitats for their associated endofauna. This provision of habitat needs to be taken into account when harvesting green Haliclona biomass for supply of its target bioactive compound for further pharmaceutical development. [ABSTRACT FROM AUTHOR]

We examined site differences in the elemental composition of the primordium and ontogenetic variability of Sr in otoliths of fish from Australia and New Zealand and, as an out-group, the North Atlantic. Differences among sites in primordium composition are slight, but significant for all five elements assayed (Sr, Pb, Cu, Zn and Hg), but principally reflect differences between the North Atlantic and SW Pacific specimens, do not replicate for independent samples in the SW Pacific and constitute a poor “natural tag” in roughy, with <25% of fish successfully assigned to source location. However, mean Sr weight-fractions at the primordium showed similar latitudinal variation across sites in Australia, New Zealand and the Tasman Sea, indicating both spatially structured populations and a common structuring process across the region. Comparisons of ontogenetic variability of Sr in otoliths from juveniles and young adults within and between sites in the SW Pacific strongly support the hypothesis that variability in this element is site-specific and environmentally sensitive, although the environmental factors involved are not obvious. The otolith analysis confirms previous suggestions that juvenile and adult Hoplostethus atlanticus are relatively sedentary, but also indicates that the population sub-structuring by age within sites is more complex and there are likely to be more spawning areas in Australian waters than previously thought. More broadly, although single point analysis of otolith composition at the primordium resolves a population structure in roughy, alone it is not precise enough to test hypotheses about the processes causing this structure. Ontogenetic variability in Sr provides better resolution of spatial structure, even in a relatively homogenous marine environment like the deep ocean, and also provides insight into behavioural and ecological factors. Ontogenetic analyses of Sr in otoliths are expensive to obtain, require more effort in specimen preparation than single point analyses, and are difficult to compare statistically, but the increased information they yield warrants their broader consideration in marine species. [ABSTRACT FROM AUTHOR]

Little Penguins, Eudyptula minor, breed in several small colonies in New Zealand and Australia. In this study, we compare the birds’ diving performances at different sites situated throughout their breeding range. Environmental conditions and breeding success vary drastically amongst colonies, but all birds feed on similar types of prey and face similar limitations on their foraging range. We examined several diving parameters and calculated the proportion of foraging zone available during breeding to examine whether oceanographic and geographic factors in the foraging zone can explain variations in diving behaviour and fledging success among the different colonies. In colonies with high fledging success, Penguin Island and Oamaru, penguins made shallow dives <50 m depth and had lower diving effort. More than 90% of the foraging zone was in waters <50 m depth in these colonies. Motuara Island also has shallow waters with 95% <50 m depth, but the fledging success was low. Phillip Island has only 42% of waters <50 m and comparatively low fledging success. Thus, penguins dived deeper and showed a higher diving effort in colonies with lower fledging success (Motuara Island and Phillip Island), indicating that they were disadvantaged compared to conspecifics from other colonies that dived shallower and with a lesser diving effort. We concluded that bathymetry is an important factor, but not the only one, which influences fledging success. [ABSTRACT FROM AUTHOR]

Coral bleaching (the loss of symbiotic dinoflagellates from reef-building corals) is most frequently caused by high-light and temperature conditions. We exposed the explants of the hermatypic coral Stylophora pistillata to four combinations of light and temperature in late spring and also in late summer. During mid-summer, two NOAA bleaching warnings were issued for Heron Island reef (Southern Great Barrier Reef, Australia) when sea temperature exceeded the NOAA bleaching threshold, and a ‘mild’ (in terms of the whole coral community) bleaching event occurred, resulting in widespread S. pistillata bleaching and mortality. Symbiotic dinoflagellate biomass decreased by more than half from late spring to late summer (from 2.5×106 to 0.8×106 dinoflagellates cm2 coral tissue), and those dinoflagellates that remained after summer became photoinhibited more readily (dark-adapted F V : F M decreased to (0.3 compared with 0.4 in spring), and died in greater numbers (up to 17% dinoflagellate mortality compared with 5% in the spring) when exposed to artificially elevated light and temperature. Adding exogenous antioxidants ( d-mannitol and l-ascorbic acid) to the water surrounding the coral had no clear effect on either photoinhibition or symbiont mortality. These data show that light and temperature stress cause mortality of the dinoflagellate symbionts within the coral, and that susceptibility to light and temperature stress is strongly related to coral condition. Photoinhibitory mechanisms are clearly involved, and will increase through a positive feedback mechanism: symbiont loss promotes further symbiont loss as the light microenvironment becomes progressively harsher. [ABSTRACT FROM AUTHOR]

Seasonal trends in the gonad index (GI) of two widely separated populations of black teatfish, Holothuria whitmaei (formerly included in Holothuria nobilis), were investigated between Pacific (Great Barrier Reef) and Indian Ocean (Ningaloo Reef) coral reefs of Australia. Reproductive activity followed a similar annual trend, with the GI of both populations peaking typically between April and June. Macroscopic and histological analysis of Ningaloo Reef specimens revealed that large germinal tubules, positioned centrally on the gonad basis, progressed through four maturity stages: growing (II); mature (III); partly spawned (IV); and spent (V). Growing tubules dominated the central region of the gonad basis between January and March, followed by an increase in the number of mature tubules throughout the GI peak (April–June). The progressive appearance of partly spawned and spent tubules between June and October suggests that spawning in H. whitmaei continues intermittently over an extended period throughout the austral winter. The examination of the gonad structure of sexually mature male and female specimens identified five tubule size classes in total (C1 to C5), each of differing physical and gametogenic status. In females, smaller C1 tubules located at the anterior edge of the gonad basis contained pre- to early vitellogenic oocytes. Larger C2 and C3 tubule cohorts, positioned centrally on the gonad basis, contained mid- to late-stage vitellogenic oocytes. Smaller C4 and C5 tubules, located at the posterior edge, contained only relict oocytes. Similar physical and gametogenic differences were apparent between tubule cohorts in male specimens. We propose that these results, together with evidence of incomplete gonad resorption over the austral summer, indicate that gonad development in H. whitmaei conforms to the predictions of the Tubule Recruitment Model (TRM). The TRM is reported rarely among tropical aspidochirotes, and results presented here (1) provide the first direct evidence of this model in H. whitmaei, and (2) confirm that this species is one of the few winter-spawning tropical invertebrates. [ABSTRACT FROM AUTHOR]

Eight polymorphic microsatellite loci were analysed in six population samples from four locations of the Australian endemic brown tiger prawn, Penaeus esculentus. Tests of Hardy–Weinberg equilibrium were generally in accord with expectations, with only one locus, in two samples, showing significant deviations. Three samples were taken in different years from the Exmouth Gulf. These showed no significant heterogeneity, and it was concluded that they were from a single panmictic population. A sample from Shark Bay, also on the west coast of Australia, showed barely detectable differentiation from Exmouth Gulf ( F ST = 0 to 0.0014). A northeast sample from the Gulf of Carpentaria showed low ( F ST = 0.008) but significant differentiation from Moreton Bay, on the east coast. However, Exmouth Gulf/Shark Bay samples were well differentiated from the Gulf of Carpentaria/Moreton Bay ( F ST = 0.047–0.063). The data do not fit a simple isolation by distance model. It is postulated that the east–west differentiation largely reflects the isolation of east and west coast populations that occurred at the last glacial maximum when there was a land bridge between north-eastern Australia and New Guinea. [ABSTRACT FROM AUTHOR]

In temperate, marine waters on the lower west coast of Australia, Rhabdosargus sarba settles in unvegetated nearshore areas and then, as it increases in size, moves progressively to nearby seagrass beds and then to exposed unvegetated nearshore areas and finally to areas around reefs where spawning occurs. The von Bertalanffy growth curves fitted to the lengths at age of R. sarba collected from the different habitats mentioned above were significantly different from each other (P<0.001). These significant differences were at least partly attributable to the fact that the size-related movement of R. sarba between habitats affects the composition of the lengths at age of this species in each habitat. The problem of producing a sound quantitative description of the overall growth of the individuals in populations such, as that of R. sarba in coastal marine waters, was overcome by incorporating logistic functions within the von Bertalanffy growth model that accommodated the probability of a fish of a given length occurring in a particular habitat. R. sarba also underwent size-related changes in habitats in two other environments, namely a temperate estuary and a subtropical embayment. Thus, as this species increases in size, it moves from nearshore, shallow waters to offshore, deeper waters in the former environment and from mangroves to areas around reefs in the latter environment. Although descriptions of the growth of individuals in the populations of R. sarba in these latter two environments were improved statistically by using the adjusted von Bertalanffy growth equation, these improvements were so small that they were considered not to be of biological significance. This was because, in contrast to the situation in temperate coastal marine waters, the samples collected from the different habitats in the estuary and subtropical embayment provided, as a whole, better representations of the compositions of the lengths at age of those two populations. The growth of R. sarba was slightly faster in the lower reaches of the temperate estuary than in either temperate coastal marine waters or the subtropical marine embayment, where food was almost certainly less abundant. [ABSTRACT FROM AUTHOR]

The fissiparous starfish genus Coscinasterias (Verrill) is represented in shallow waters around many of the world's continents. This wide distribution could be explained by dispersal, vicariance, or translocation associated with shipping, and represents an excellent system for marine biogeographic research. We conducted a global phylogeographic analysis of 42 Coscinasterias mtDNA cytochrome oxidase 1 sequences (15 haplotypes) from 18 sites, including representatives of all four recognised species. Phylogenetic analysis yielded a robust phylogeny, with strong support for the monophyly of the genus (90% bootstrap support) and of each separate species (99–100%). Haplotypes exhibited strong phylogeographic structure, with robust mtDNA clades often associated with distinct land masses. A general lack of genetic differentiation within sites may reflect fissiparity. However, shared haplotypes over larger distances (e.g. across Japan), and the presence of related haplotypes on adjacent land masses (e.g. Tasmania, New Zealand; 1.6–1.8%) suggest that long-distance dispersal is an important biogeographical process for Coscinasterias. The 4.0–4.4% divergence between Japanese and South African sister groups may relate to transequatorial dispersal around the onset of the Pleistocene. Divergent Atlantic and Mediterranean populations of C. tenuispina (maximum 1.5%) may deserve subspecific recognition, and high divergences within Australian C. muricata (maximum 8.0%) suggest a species complex. [ABSTRACT FROM AUTHOR]

The Australasian gannet (Morus serrator) population has increased considerably over the past century, both in New Zealand and Australia. Since 1980, the population in Australian waters has increased threefold, from 6,600 breeding pairs to approximately 20,000 pairs in 1999 2000, a rate of 6% per year. Reasons for the increase in the Australasian gannet population are poorly understood: here we consider the possible effects of recent fluctuations in climatic and oceanographic conditions, and changes in major local commercial fisheries. A significant trend towards more frequent, and stronger, El Niño Southern Oscillation events, warmer summer sea surface temperatures in Bass Strait, increased annual catches and catch per unit effort in the Victorian pilchard (Sardinops sagax) fishery and potential increased discarding of fisheries bycatch may account for at least some of the observed increase in the Australasian gannet population. The potential interactive effects of these factors on prey distribution and abundance and consequently on gannet numbers are discussed. [ABSTRACT FROM AUTHOR]

Presents a study which examined the genetic diversity of symbiotic dinoflagellates Symbiodinum sp. in the widespread scleractinian coral Plesiastrea versipora along the southern and eastern coast of Australia. Methodology; Results; Discussion.

Focuses on a study of the short-term movements and behavior of the whale sharks at Ningaloo Reef in Western Australia. Information on whale sharks; Materials and methods; Results of the study.

Linuparus trigonus (Palinuridae) was collected from northeast Australia at depths of 220 to 300 m in the austral summer of 1985-1986 and its diet was analysed for diel feeding-periodicity and composition. The sex and size of the lobsters and the depth at which they were caught were recorded. About 35% of the foreguts were less than 10% full. L. trigonus appears to be a predator of slow-moving or nearsessile benthic invertebrates; its diet is mainly bivalves, gastropods, ophiuroids, crustaceans, polychaetes, and foraminiferans. Most dietary items differed significantly between the size classes of lobster. The frequency of crustacean remains increased with depth and more gastropods were consumed by lobsters caught at 260 m than at other depths. No significant periodicity in feeding was found for L. trigonus. The foreguts of three Metanephrops spp. (Nephropidae) collected from north-west Australia in August 1983 ( M. andamanicus) and January/February 1984 ( M. australiensis and M. boschmai) were nearly empty, and nearly half were less than 10% full. Fish, crustaceans and squids were the most common food items eaten. The main food items varied between the species: M. andamanicus ate nearly equal amounts of fish and crustaceans; M. australiensis ate chiefly crustaceans; M. boschmai mainly ate fish and seldom fed on squid. Metanephrops spp. appear to feed by attacking mobile animals and tearing off appendages or by scavenging. [ABSTRACT FROM AUTHOR]

The feeding behaviour of leaf eating crustaceans feeding on leaves shed by Avicennia marina, Bruguiera gymnorhiza and Rhizophora stylosa in the mangrove forest at Myora Springs, Queensland, Australia was studied between 1980 and 1984. Individual Sesarma erythrodactyla (carapace >9 mm long), one of the most abundant species of crabs in the forest, processed approximately half a leaf from any of the three species of mangroves in 24 h under laboratory conditions. of the amount of leaf material processed, 20% was lost from the mandibles due to 'sloppy feeding', 68% was egested as faeces and 12% converted into crab biomass. Crabs processed more leaf material at 30°C than at 20°C. S. erythrodactyla preferred leaves of A. marina to those of the other two species, probably because leaves of A. marina have a lower tannin and a higher nitrogen content. Of the other two species, B. gymnorhiza was preferred to R. stylosa. Among leaves of R. stylosa, S. erythrodactyla exerts a strong preference for aged rather than freshly fallen, and for thick rather than thin leaves. The mesofauna (carapace length <9.0 mm) which processed dead mangrove leaves comprised juveniles of S. erythrodactyla, the crab Ilyograpsus paludicola, the isopod Exosphaeroma alata and the amphipods Orchestia sp. and Melita sp. These species processed between 0.2 and 24.7 mg dry wt of a leaf per individual over a period of 4 d. Of this, 72 to 85% was egested as faeces. The significance of leaf eating crabs to nutrient cycling in mangrove forests is discussed. I conclude that leaf processing by crustaceans shortens the time span between leaf fall and consumption of leaf material by organisms. This may have the effect of conserving leaf biomass inside the mangrove forest. [ABSTRACT FROM AUTHOR]

This study investigated an incubation method which employed simultaneous measurement of CO production and O consumption rates to calculate the RQ (respiratory quotient; CO production rate: O consumption rate) of individual benthic marine invertebrates. Carbon dioxide production rates were calculated from changes in CO concentration determined using seawater pH. O consumption rates were calculated from changes in O concentration with a correction applied for O flux across the air/water interface due to gaseous exchange. Species examined were Triphyllozoon sp. cf. moniliferum (MacGillivray 1860), a bryozoan; Herdmania momus (Savigny), a solitary ascidian; Poneroplax albida (Blainville 1825), a chiton; and Haliotis roei (Gray 1826), an abalone. Six individuals of each were collected on 14 November 1985 from the limestone walls of a cave in a nearshore reef off Marmion, Western Australia. After acclimation for 6 h in experimental conditions, rates of CO production and O consumption were measured. A minimum period of 4 h was required to obtain consistent RQ values for each species. The standard error (SE) of the (calculated) RQ ratio was 14 to 33% of the mean in incubations of 4 h, and less than 14% in incubations of 4 to 12 h. The RQ is commonly used as an indicator of unknown catabolic substrates by comparing it with biochemically determined limits for known substrates. This study provides a strong argument against using the RQ of individual animals to draw any conclusions about catabolic substrates. Unexplained variation in the components of the RQ of an individual, measured over short time periods, and the potential involvement of stored reserves in catabolism, over longer time periods, obscure the relationship between the RQ of individual animals and the ratio's biochemically determined limits. [ABSTRACT FROM AUTHOR]

The occurrence of unusual symbiotic microorganisms was examined in the intestines of a range of fish from the Great Barrier Reef, Australia. The fish taxa examined included 26 species of the family Acanthuridae, as well as representatives of phylogenetically related and herbivorous taxa. The microorganisms, referred to as protists, were only found in herbivorous and detritivorous members of the Acanthuridae. Protists were not found in planktivorous acanthurids, nor in any members of the families Kyphosidae, Pomacentridae, Scaridae, Zanclidae, Siganidae and Bleniidae we examined. In addition, protists were absent from the herbivorous acanthurids A. xanthopterus and A. nigricans. A range of protist forms, characterized by differences in size (8 to 417 μm), shape and mode of cell division (daughter-cell production and binary fission), was observed. The occurrence of these forms appeared to be correlated with host feedingecology. Large forms (>100 μm) of the protists were only found in acanthurids which fed over hard-reef substrata. Smaller forms were found in sand-grazing and detritivorous species. One of the protist forms appears identical to protists previously reported from Red Sea acanthurids. [ABSTRACT FROM AUTHOR]

A bloom of the diatom Rhizosolenia chunii Karsten sensu Sundström occurred in Port Phillip Bay (38°S; 145°E), southeastern Australia, between late August and mid-October 1987. Coincident with this bloom, mussels ( Mytilus edulis planulatus), scallops ( Pecten alba) and flat oysters ( Ostrea angasi) throughout the Bay developed a bitter taste that was so unpleasant and persistent that mussels became unmarketable for 7 mo. The bitter taste was concentrated in the digestive gland, which also showed extensive inflammation and degeneration. Digestive gland lesions were evident in mussels during September 1987, but became progressively more severe and, in the chronic end-stage were associated with high shellfish mortality 3 to 8 mo after the bloom had ceased. This study provides strong indirect evidence that the bitterness and the toxicity were caused by a bloom of R. chunii. R. chunii is the first species of diatom to be associated with shellfish mortality and, as the mortality occurred many months after the bloom had ceased, we suggest that the toxicity of certain algal blooms may be difficult to detect rather than uncommon. [ABSTRACT FROM AUTHOR]

Scyphomedusae collected from Port Phillip Bay, Victoria, Australia, between 1984 and 1986, consumed a variety of zooplankton. The percentage composition of gut contents of Cyanea capillata (Linné) in order of decreasing importance was larvaceans 31%, cladocerans 29%, fish eggs 14%, copepods 11%, hydromedusae 9%, and ascidian tadpoles 3%. The percentage composition of gut contents of Pseudorhiza haeckeli Haacke was fish eggs 41%, copepods 33%, larvaceans 8%, cladocerans 4%, crab zoea 4%, and decapod larvae 1%. Both species of scyphomedusae showed strong positive selection for fish eggs and yolk-sac larvae, and negative selection for other prey items. When fish eggs were omitted from the selectivity analyses, C. capillata showed positive selection for amphipods, decapods, crab zoea, Podon spp., larvaceans and ascidian tadpoles, and negative selection for Evadne spp. and all copepod taxa. Pseudorhiza haeckeli showed positive selection for amphipods, decapod larvae, crab zoea and cladocerans, and negative selection for cirripede larvae, larvaceans and hydromedusae. Amongst copepods, P. haeckeli showed positive selection for calanoid and harpacticoid copepods and negative selection for cyclopoid copepods. [ABSTRACT FROM AUTHOR]

A total of 34 zooplanktonic taxa were common in emergence trap, reentry trap, and net-tow samples taken in the lagoon of Heron Reef, Great Barrier Reef, between 27 February and 22 March and between 11 June and 4 July 1985. Twenty-nine of these taxa were classified as demersal (17 taxa), meroplanktonic and larval (10 taxa), or incidental (2 taxa). The remaining five multispecific groups yielded variable results. Differences were observed between two locations separated by 200 m, with emergence 2 to 62 times greater for 22 taxa at a deeper site with larger coral formations. Most zooplankters were more common (2 to 122 times) in samples from 1 m areas around 0.25 to 0.5 m patches of branching coral. However, two species of copepods, Pseudodiaptomus colefaxi and Metis holothuriae, were taken in greater numbers (3 to 12 times) from open sand. Seasonal increases (2 to 322 times) were observed for 13 adult taxa and 8 classes of larvae or juveniles in the summer and for 10 adult taxa and one larval group in the winter. Fourteen of the 17 demersal taxa and 4 groups of large larvae or juveniles emerged in numbers 2 to 323 times greater during lunar quarters or new moons. In contrast, 6 larval taxa and 4 groups of small or transparent adults displayed significant emergence during full moons. Five diurnal emergence patterns were shown by 27 taxa, with patterns varying primarily among lunar periods. The variety of taxon-specific patterns observed in this study highlight a need for caution when generalizing about demersal zooplankton. [ABSTRACT FROM AUTHOR]

In view of their possible involvement in ammonium assimilation in the coral/algal symbiosis, we have purified two distinct glutamate dehydrogenase isoenzymes from the symbiotic dinoflagellate Symbiodinium microadriaticum (Freudenthal) extracted from the staghorn coral Acropora formosa collected from Magnetic Island, North Queensland, Australia, in 1986-1987. An NADPH-specific glutamate dehydrogenase (GDH) displayed biphasic kinetics with respect to ammonium as the variable substrate; at low substrate concentrations the apparent K was below 1 m M, whereas at high substrate concentrations the corresponding value was approximately 200 m M. The NADPH-GDH displayed extremely low activity in the direction of glutamate oxidation; together with the kinetic data this suggests a probable role in ammonium assimilation. A second (NADH-specific) GDH was found to have both amination and deamination activities, and presumably functions in vivo in glutamate oxidation. Kinetic constants are reported for both GDH isoenzymes. [ABSTRACT FROM AUTHOR]

Sharpnose puffers, Canthigaster valentini (Pisces: Tetraodontidae) at Lizard Island, Australia, live in made-dominated haremic social and mating systems. The hypothesis was that mature females are restricted in their movements and can be monopolized by some males. Field experiments at Lizard Island, Great Barrier Reef, between January and March 1983 showed that mature females were still territorial in the absence of males and movements of females were not controlled by males. Males abandoned their territories when their females were removed. The territorial behavior of those males with access to females (territorial males) restricted the access of other males (bachelor males) to them. Bachelor males took over harems and became territorial males when established territorial males were removed. The results of the experiments thus supported the hypothesis. [ABSTRACT FROM AUTHOR]

Daytime sampling of mangrove and seagrass ( Halophila/Halodule community) habitats every 7 wk at Alligator Creek, Queensland, Australia, over a period of 13 mo (February 1985-February 1986) using two types of seine net, revealed distinct mangrove and seagrass fish and crustacean faunas. Total abundance of fish and relative abundance of small and large fish also varied between habitats and seasonally. Post-larval, juvenile and small adult fish captured with a small seine-net (3 mm mesh) were significantly more abundant (4 to 10 times) in the mangrove habitat throughout the 13 mo of sampling. Mangrove fish abundance showed significant seasonality, greatest catches being recorded in the warm, wet-season months of the year. Relative abundances of larger fish (captured in a seine net with 18 mm mesh) in the two habitats varied throughout the year, but did not show a seasonal pattern. At the same site, small crustaceans were significantly more abundant in the mangroves in all but one dryseason sample. Similar comparisons for three riverine sites, sampled less frequently, in the dry and wet seasons of 1985 and 1986, respectively, showed that in general mangrove habitats had significantly more fish per sample, although the relative abundance of fish in mangroves and other habitats changed with season. Crustacean catches showed a similar pattern, except that densities among sites changed with season. Fish and crustacean abundance in mangroves varied among sites, indicating that estuaries differ in their nursery-ground value. The juveniles of two commercially important penaeid prawn species ( Penaeus merguiensis and Metapenaeus ensis) were amongst the top three species of crustaceans captured in the study, and both were significantly more abundant in the mangrove habitat. By contrast, mangroves could not be considered an important nursery for juveniles of commercially important fish species in northern Australia. However, based on comparisons of fish catches in other regions, the results of the present study indicate the importance of mangroves as nursery sites for commercially exploited fish stocks elsewhere in South-East Asia. [ABSTRACT FROM AUTHOR]

Daily growth increments on otoliths were used to age larvae of the pleuronectid fluonders Rhombosolea tapirina Günther and Ammotretis rostratus Günther, collected from Port Phillip Bay, Victoria, Australia, in winter 1984. Daily formation of growth increments was confirmed for R. tapirina by examining the growth of the marginal increment on otoliths of larvae collected over two 24h periods in winter 1985. The first distinctive growth increment was laid down approximately 5 d after hatching, at the onset of external feeding. Growth of flounder larvae was exponential from an early feeding stage to notochord flexion at approximately 30 d after hatching. The specific growth rate was very similar for the two species, at slightly over 4% of standard length per day. Predicted absolute growth rate of R. tapirina larvae increased from approximately 0.10 mm d in early feeding larvae to approximately 0.23 mm d in flexion-stage larvae, compared with 0.12 to 0.28 mm d for A. rostratus larvae of equivalent ages. Exponential models did not adequately describe growth of first-feeding larvae, which was slower than predicted. Growth in the field was faster than that recorded for the same species in the laboratory at higher water temperatures and prey abundances. Otolith growth accelerated markedly in relation to growth in length at the beginning of metamorphosis, causing a significant alteration in the morphology of growth increments, and eventually leading to the cessation of production of visible increments. [ABSTRACT FROM AUTHOR]

Regression analysis on data collected from Port Phillip Bay and Western Port, Australia in 1979 shows that there is a significant equilibrium relationship between total recoverable lead in seawater and its concentrations in the mussel Mytilus edulis ( P<0.001). The concentration of lead in seawater should not exceed 1.27 μg l if the mussel is not to reach a lead concentration of 2.5 mg kg wet weight, a value frequently used as a food standard for human consumption. When a lead value of 2.5 mg kg wet weight is reached, the concentration factor by mussels for lead from seawater is 1969. The critical value of 1.27 μg l could be used as a marine water-quality criterion for lead in waters where mussels are harvested. [ABSTRACT FROM AUTHOR]