Distribution changes after settlement in six species of damselfish (Pomacentridae) in One Tree Island lagoon, Great Barrier Reef

While larval supply patterns play a major role in determining the distribution and abundance of reef fishes at a range of spatial and temporal scales, events occurring in the weeks after settlement may also significantly alter the demography of a juvenile population. I monitored over 2 summers the arrival of new recruits of 6 species of benthic damselfish onto continuous and patch reef habitat in One Tree Island lagoon. Each species had specific habitat preferences, and most showed some form of patchiness in spatial and temporal distribution at settlement; however, this was most likely a result of group settlement rather than habitat patchiness. Tagged recruits of Pomacentrus amboinensis remained within 1 m of their settlement site for at least the first 36 d on continuous reef, while known individuals of other species also moved little during this period, suggesting that disappearances were likely to be due to mortality. Mortality of recruits varied among species, years and habitats (patch vs continuous reef), and consequently spatial distributions of fish changed after settlement at the scale of 10s of metres (within-site) and several kilometres (among 8 sites). The spatial patchiness in distributions was not consistent among species, sites or years, suggesting that spatial variation in substrate did not have a major effect on settlement variation at this scale. These results show that the settlement signal may be obscured in the first few weeks post-settlement, and that less-frequent censuses, commonly used as proxies for high-frequency monitoring of settlement, may not accurately hindcast spatial or temporal patterns of settlement

Ability to home in small site-attached coral reef fishes

© 2016 The Fisheries Society of the British Isles. The ability of two common, site-attached coral-reef fishes to return to their home corals after displacement was investigated in a series of field experiments at One Tree Island, southern Great Barrier Reef. The humbug Dascyllus aruanus was displaced up to 250 m, with 42% of individuals returning home, irrespective of body size, displacement, direction (up or across currents) and route complexity, while for the lemon damselfish Pomacentrus moluccensis 35% of individuals returned overall, with 33% from the greatest displacement, 100 m along a reef edge. Given that the home range of both species is <1 m(2) , over their 10+ year life span, the mechanisms and motivations for such homing ability are unclear but it may allow resilience if fishes are displaced by storm events, allowing rapid return to home corals

Rapid growth and short life spans characterize pipefish populations in vulnerable seagrass beds

© 2016 The Fisheries Society of the British Isles. The life-history traits of two species of pipefish (Syngnathidae) from seagrass meadows in New South Wales, Australia, were examined to understand whether they enhance resilience to habitat degradation. The spotted pipefish Stigmatopora argus and wide-bodied pipefish Stigmatopora nigra exhibit some of the shortest life spans known for vertebrates (longevity up to 150 days) and rapid maturity (male S. argus 35 days after hatching (DAH) and male S. nigra at 16-19 DAH), key characteristics of opportunistic species. Growth rates of both species were extremely rapid (up to 2 mm day-1), with seasonal and sex differences in growth rate. It is argued that short life spans and high growth rates may be advantageous for these species, which inhabit one of the most threatened marine ecosystems on earth

Changes in a fish assemblage after a coral bleaching event

Large-scale bleaching events are major disturbances to coral health and community structure, but may also affect other coral reef taxa, such as fishes. In 1997-1998, wide-spread coral bleaching and mortality occurred across the Great Barrier Reef, caused by increases in sea surface temperatures resulting from El Niño Southern Oscillation. As part of this event, in February-March 1998, there was extensive bleaching within One Tree Island lagoon (southern Great Barrier Reef), such that almost 12 mo later there was a significant reduction of live coral cover at some sites. We monitored the distribution of adults and recruitment of damselfishes (Pomacentridae) to sites within One Tree Island in 1993-1995 and in 1999. Fish species that normally associate with live corals showed relatively lower recruitment at bleached sites compared to the same sites pre-bleaching or to recovered sites and, as a result, species diversity and assemblage structure of recruits changed. Compared to 1993/1995 densities, adult Pomacentrus wardi, P. moluccensis and Chrysiptera rollandi densities dropped at bleached sites, but not at unbleached sites. While P. moluccensis directly associate with live corals, the other 2 species do not. This study has demonstrated that indirect effects of bleaching can include changes in-assemblage structure of reef fish adults and recruits

Zooplankton patchiness and the associated shoaling response of the temperate reef fish Trachinops taeniatus

The grouping behaviour of fishes plays an important role in the success of the group and individual in terms of foraging, reproduction and predator avoidance. The temperate Sydney (Australia) reef fish species Trachinops taeniatus was investigated between February and September 2002 to determine whether there was a relationship between shoal dynamics and zooplankton prey distribution. The diet of T. taeniatus consisted mainly of Copepoda. T. taeniatus shoals were strongly associated with the largest patches of Copepoda, with shoal size increasing as prey density increased. Available Copepoda per fish, however, decreased with shoal size, presenting a possible 'overmatching' foraging situation. The present study suggests there may be an optimum shoal size to achieve maximum prey intake, and that shoal location and size may be linked to the distribution of zooplankton prey. © Inter-Research 2005

Predicting range-shift success potential for tropical marine fishes using external morphology

© 2016 The Author(s) Published by the Royal Society. All rights reserved. With global change accelerating the rate of species' range shifts, predicting which are most likely to establish viable populations in their new habitats is key tounderstanding howbiological systemswill respond. Annually, in Australia, tropical fish larvae from the Great Barrier Reef (GBR) are transported south via the East Australian Current (EAC), settling into temperate coastal habitats for the summer period, before experiencing near-100% mortality in winter. However, within 10 years, predicted winter ocean temperatures for the southeast coast of Australia will remain high enough for more of these so-called 'tropical vagrants' to survive over winter. We used a method of morphological niche analysis, previously shownto be an effective predictor of invasion success by fishes, to project which vagrants have the greatest likelihood of undergoing successful range shifts under these newclimatic conditions. We find that species from the family of butterflyfishes (Chaetodontidae), and the moorish idol, Zanclus cornutus, are most likely to be able to exploit new niches within the ecosystem once physiological barriers to overwintering by tropical vagrant species are removed. Overall, the position of vagrants within the morphospace was strongly skewed, suggesting that impending competitive pressures may impact disproportionately on particular parts of the native community

Wave-sheltered embayments are recruitment hotspots for tropical fishes on temperate reefs

© Inter-Research 2016. Poleward redistribution of species, facilitated by global warming, will be compromised if habitats at higher latitudes do not support the species' early life stages. For tropical reef fishes, reef structure may mediate colonisation of temperate regions; however, an understanding of key habitat requirements for colonisation is currently lacking. We show that density, diversity (taxonomic and trophic) and species richness of newly recruited tropical reef fishes were greater in embayed than exposed reefs in 2 mid-latitude temperate zones, where coastal waters are rapidly warming: southeastern Australia (30.5-33° S) and western Japan (32-33.5° N). Dietary generalists (e.g. planktivores and herbivores) and specialists (corallivores) associated more commonly with embayed reefs. Wave exposure was a stronger predictor of the density and richness of dietary generalists than water temperature, latitude, predatory fish densities, reef rugosities, benthos and distance to river mouths. Corallivores were strongly associated with branching corals, which were exclusive to highly sheltered reefs. We also explored habitat associations of 7 focal species within a coral reef, One Tree Island (OTI), Great Barrier Reef. Four species associated with wave - sheltered over exposed reef on OTI and temperate Australian reef. However, Abudefduf vaigiensis, Pomacentrus coelestis and Acanthurus triostegus associated more with wave-sheltered reef in temperate regions. We hypothesise that cool temperate waters promote greater sheltering of some warm-adapted, tropical fishes by impacting their swimming/physiological performance. Results suggest availability of embayed temperate reefs may influence where some tropical fishes colonise with warming waters, through impacting recruitment. Wave exposure of reefs should be considered when predicting geographic responses of tropical fishes to climate change

Unforeseen high temperature and humidity stability of FeCl3 intercalated few layer graphene

This is the final version of the article. Available from the publisher via the DOI in this record.We present the first systematic study of the stability of the structure and electrical properties of FeCl3 intercalated few-layer graphene to high levels of humidity and high temperature. Complementary experimental techniques such as electrical transport, high resolution transmission electron microscopy and Raman spectroscopy conclusively demonstrate the unforseen stability of this transparent conductor to a relative humidity up to 100% at room temperature for 25 days, to a temperature up to 150°C in atmosphere and to a temperature as high as 620°C in vacuum, that is more than twice higher than the temperature at which the intercalation is conducted. The stability of FeCl3 intercalated few-layer graphene together with its unique values of low square resistance and high optical transparency, makes this material an attractive transparent conductor in future flexible electronic applications