In stark contrast to widespread declines along the Scotia Arc,a survey of the South Sandwich Islands finds a robust seabird community

The South Sandwich Islands, in the South Atlantic Ocean, are a major biological hot spot for penguins and other seabirds, but their remoteness and challenging coastlines preclude regular biological censuses. Here we report on an extensive survey of the South Sandwich Islands, the first since the late 1990s, which was completed through a combination of direct counting, GPS mapping, and interpretation of high-resolution commercial satellite imagery. We find that the South Sandwich Islands host nearly half of the world’s Chinstrap Penguin (Pygoscelis antarctica) population (1.3 million breeding pairs), as well as c. 95,000 breeding pairs of Macaroni Penguins (Eudyptes chrysolophus), and several thousand breeding pairs of Gentoo Penguins (Pygoscelis papua). Despite being at the northern edge of their breeding range, we found an unexpectedly large (≥125,000 breeding pairs) population of Adélie Penguins (Pygoscelis adeliae). Additionally, we report that nearly 1900 pairs of Southern Giant Petrels (Macronectes giganteus) breed in the South Sandwich Islands, 4 % of the global population, almost all of which are found on Candlemas Island. We find that the South Sandwich Islands have not experienced the same changes in penguin abundance and distribution as the rest of the Scotia Arc and associated portions of the western Antarctic Peninsula. This discovery adds important context to the larger conversation regarding changes to penguin populations in the Southern Ocean.     

Collection and aging of greater amberjack <Emphasis Type="Italic">Seriola dumerili</Emphasis> larvae and juveniles around the Penghu Islands,Taiwan

To investigate the early life history of Seriola dumerili, we first validated otolith daily increments using reared fish (11–51 days after hatching). Four larval and early-juvenile S. dumerili were collected in May and July 2015 around the Penghu Islands, Taiwan (23.45–23.70 °N, 119.40–119.70 °E), by surface larval net towing, but not from drifting seaweeds. Seriola dumerili were caught at the thermal front, and the total lengths and ages ranged 7.4–42.5 mm and 18–56 days, respectively. Our results indicate that the hatching dates of S. dumerili were April to June and larvae may have been accumulated in the frontal zone before the juvenile phase.     

New species of pelagic eelpouts of the genus <Emphasis Type="Italic">Melanostigma</Emphasis> (Zoarcidae) from Western Antarctica

A new species, Melanostigma olgae sp. n., is described from the Southern Ocean. The type series was obtained along the South Sandwich Islands (Scotia Sea, Western Antarctic) at the depths of 800?850 m. The new species differs from the other representatives of Melanostigma genus by the original combination of the features of the seismosensory system, axial skeleton, and coloration. The homologization of the structural elements (senses) of the head canals of the lateral line has been done for the first time for the Melanostigma. Morphology of M. olgae allows considering this species as the most evolutionary advanced within the representatives of this genus inhabiting the Southern Ocean. The key of the Antarctic species of the genus Melanostigma is provided.     

The reproductive biology and early life ecology of a common Caribbean brain coral, <Emphasis Type="Italic">Diploria labyrinthiformis</Emphasis> (Scleractinia: Faviinae)

Despite the fact that most of the severe demographic bottlenecks in coral populations occur during their earliest life stages, information on the reproductive biology and early life history traits of many coral species is limited and often inferred from adult traits only. This study reports on several atypical aspects of the reproductive biology and early life ecology of the grooved brain coral, Diploria labyrinthiformis (Linnaeus, 1758), a conspicuous reef-building species on Caribbean reefs. The timing of gamete release of D. labyrinthiformis was monitored in Curaçao over eight consecutive months, and embryogenesis, planulae behavior, and settlement rates were observed and quantified. We further studied growth and symbiont acquisition in juvenile D. labyrinthiformis for 3.5 yr and compared settler survival under ambient and nutrient-enriched conditions in situ. Notably, D. labyrinthiformis reproduced during daylight hours in six consecutive monthly spawning events between May and September 2013, with a peak in June. This is the largest number of reproductive events per year ever observed in a broadcast-spawning Caribbean coral species. In settlement experiments, D. labyrinthiformis planulae swam to the bottom of culture containers 13 h after spawning and rapidly settled when provided with settlement cues (42% within 14 h). After 5 months, the survival and growth rates of settled juveniles were 3.7 and 1.9 times higher, respectively, for settlers that acquired zooxanthellae within 1 month after settlement, compared to those that acquired symbionts later on. Nutrient enrichment increased settler survival fourfold, but only for settlers that had acquired symbionts within 1 month after settlement. With at least six reproductive events per year, a short planktonic larval phase, high settlement rates, and a positive response to nutrient enrichment, the broadcast-spawning species D. labyrinthiformis displays a range of reproductive and early life-history traits that are more often associated with brooding coral species, illustrating that classical divisions of coral species by reproductive mode alone do not always reflect the true biology and ecology of their earliest life stages.     

Life history differences and latitudinal variation in recruitment in two species of arctic-boreal perciform fishes,the fish doctor <Emphasis Type="Italic">Gymnelus viridis</Emphasis> and the Arctic shanny <Emphasis Type="Italic">Stichaeus punctatus</Emphasis>

Growth and recruitment were examined in two arctic-boreal, shallow water marine perciform species: the fish doctor Gymnelus viridis (Zoarcidae) and the Arctic shanny Stichaeus punctatus (Stichaeidae). G. viridis ranges in the Canadian Arctic from northern Hudson Bay to northern Ellesmere Island, whereas S. punctatus has a more southerly range from Nova Scotia coastal waters to northern Hudson Bay. At Nuvuk Islands in northeastern Hudson Bay, where the two species are sympatric in shallow water, they had comparable juvenile growth rates but temporal variation in 0+ recruitment was substantially greater in S. punctatus. This difference may stem from their contrasting early life histories. S. punctatus spawns large numbers of small demersal eggs that hatch into pelagic larvae, whereas G. viridis spawns small numbers of large demersal eggs that hatch directly into demersal juveniles with no pelagic stage, suggesting that recruitment in G. viridis should be less sensitive to yearly variation in the onset of the ice-free period in Hudson Bay and the subsequent pulse of pelagic invertebrate production. Relative to Nuvuk, recruitment variation in G. viridis was found to be greater at Resolute, Cornwallis Island, close to its northern range limit, whereas recruitment variation in S. punctatus was not evident in Newfoundland, closer to its southern range limit.     

Influence of environmental variables on the larval stages of anchovy, <Emphasis Type="Italic">Engraulis encrasicolus</Emphasis>, and sardine, <Emphasis Type="Italic">Sardinops sagax</Emphasis>, in Algoa Bay,South Africa

We investigated the environmental drivers of larval abundance of anchovy Engraulis encrasicolus and sardine Sardinops sagax in Algoa Bay, Eastern Cape (South Africa). This study comprised a pre-drought post-drought time period, comparing the responses of the fish larvae to different factors before and after the drought. The current study presents, for the first time, which environmental variables are affecting the anchovy and sardine larvae populations in the region. Easterly wind speed and zooplankton density were the only environmental variables that presented a significant change between the pre- and post-drought periods, increasing after the drought. Generalized additive models (GAMs) were used in order to explore the effects that environmental factors might have in the abundance of anchovy and sardine larvae in Algoa Bay. Specifically, the GAM that best explained the deviance of the anchovy larvae dynamics included the covariates rainfall, easterly wind speed, Chl a concentration, sardine larvae abundance and the interactions SST*Chla and sard*SST. The GAM best explaining sardine larvae abundance included only the easterly wind speed as a covariate. This model showed that there was a positive relationship between the higher values of wind speed and sardine larvae abundance.     

Effects of nonnative invertebrates on two life stages of the native eastern oyster <Emphasis Type="Italic">Crassostrea virginica</Emphasis>

Since their recent introductions into Florida waters, three sessile invertebrates [Perna viridis (Asian green mussel), Mytella charruana (charru mussel) and Megabalanus coccopoma (pink titan acorn barnacle)] have expanded their range along the Atlantic coast in estuarine waters. Little research has been done to understand how these nonnative species interact with the ecologically and economically important eastern oyster Crassostrea virginica. To assess the potential effects of P. viridis, M. charruana and M. coccopoma on C. virginica, the following questions were addressed in manipulative experiments. (1) Does the presence of nonnative species decrease oyster larval settlement? (2) Do oyster larvae avoid settling on nonnative species? (3) Do nonnative species decrease survival of juvenile oysters (spat)? (4) Do nonnative species hinder spat growth? We included two controls: absence of nonnative species and presence of the native mussel Geukensia demissa. The nonnative species influenced settlement, growth and survival of C. virginica in different ways. M. coccopoma and P. viridis negatively influenced larval settlement, whereas M. charruana had no influence on the total number of settled larvae. Oyster larvae avoided settling on all three nonnative species and the native G. demissa. Both nonnative mussels negatively affected survival of juvenile oysters but only M. charruana also reduced spat growth. The native mussel, G. demissa, had no negative impacts on total settlement, survival and growth of C. virginica; in fact, it increased larval settlement in some trials. These three nonnative species should be classified as invasive because all had negative effects on native C. virginica.     

The diet of the Antarctic fur seal <Emphasis Type="Italic">Arctocephalus gazella</Emphasis> at the South Orkney Islands in ten consecutive years

To improve the knowledge on the Antarctic fur seal foraging behavior, evaluate whether changes in its diet are associated with changes in prey availability, and evaluate whether fisheries had negative impacts on Antarctic fur seal populations, a total of 1359 scats of non-breeding males were collected in ten consecutive sampling periods between 1994 and 2003 at Laurie Island, South Orkney Islands. Antarctic krill was the most numerous prey throughout the sampling period followed in importance by fish prey. Antarctic krill also predominated by reconstructed mass, except during 1994 and 1998 when penguins were the most important prey, and during 1995 when fish dominated. Among fish, demersal-benthic species (mainly Gobionotothen gibberifrons, Chaenocephalus aceratus and Chionodraco rastrospinosus) dominated the diet except in 1997, 1998, 1999 and 2002 when myctophids (mainly Gymnoscopelus nicholsi and Electrona antarctica) were the most important fish prey. In seasons when fish dominated the diet, the diet was primarily comprised of demersal species. Although our results are in overall agreement with previous studies, the contribution to the diet of the main preys changed throughout the sampling period, probably in parallel with changes in prey abundance. According to historical results on fish consumption, the fisheries carried out in the past have had negative impacts on seal populations from the South Orkney Islands.     

Reproductive biology of <Emphasis Type="Italic">Astyanax lacustris</Emphasis> (Characiformes: Characidae) in the southern Pantanal floodplain,upper Paraguay River basin,Brazil

We studied the reproductive biology of Astyanax lacustris in the southern Pantanal, Brazil. A total of 382 fish were analyzed from February 2009 to January 2011. The sex ratio differed significantly from 1:1, with a larger proportion of females (χ² = 27.24; p < 0.001). Females achieve higher standard length than males (mean 72.30 mm and 56.51 mm, respectively), and possess negative allometric growth while males have positive allometric growth. Size at first maturation did not differ between sexes. The greatest reproductive activity occurred during the rainy season, when temperatures were highest (November to February). Total fecundity was significantly correlated with standard length (r_s = 0.74; p = 0.01), and spawn type was total. Then, the life history traits of A. lacustris are adjusted to seasonal variation in the Southern Pantanal.     

Modeled connectivity of <Emphasis Type="Italic">Acropora millepora</Emphasis> populations from reefs of the Spratly Islands and the greater South China Sea

The Spratly Island archipelago is a remote network of coral reefs and islands in the South China Sea that is a likely source of coral larvae to the greater region, but about which little is known. Using a particle-tracking model driven by oceanographic data from the Coral Triangle region, we simulated both spring and fall spawning events of Acropora millepora, a common coral species, over a 46-yr period (1960–2005). Simulated population biology of A. millepora included the acquisition and loss of competency, settlement over appropriate benthic habitat, and mortality based on experimental data. The simulations aimed to provide insights into the connectivity of reefs within the Spratly Islands, the settlement of larvae on reefs of the greater South China Sea, and the potential dispersal range of reef organisms from the Spratly Islands. Results suggest that (1) the Spratly Islands may be a significant source of A. millepora larvae for the Palawan reefs (Philippines) and some of the most isolated reefs of the South China Sea; and (2) the relatively isolated western Spratly Islands have limited source reefs supplying them with larvae and fewer of their larvae successfully settling on other reefs. Examination of particle dispersal without biology (settlement and mortality) suggests that larval connectivity is possible throughout the South China Sea and into the Coral Triangle region. Strong differences in the spring versus fall larval connectivity and dispersal highlight the need for a greater understanding of spawning dynamics of the region. This study confirms that the Spratly Islands are likely an important source of larvae for the South China Sea and Coral Triangle region.     

No effect of round goby <Emphasis Type="Italic">Neogobius melanostomus</Emphasis> colonisation on young-of-the-year fish density or microhabitat use

The round goby Neogobius melanostomus has recently invaded several major freshwater systems in Europe and North America. Despite numerous studies predicting an impact on native fish assemblages, few have attempted to demonstrate it. In this case study, we monitored the effect of N. melanostomus colonisation on abundance and habitat utilisation of both young-of-the-year (YOY) native fish and YOY western tubenose goby Proterorhinus semilunaris in a typical, medium-sized European river. Colonisation by N. melanostomus had no apparent effect on either native fish abundance and species richness or P. semilunaris abundance. Moreover, after colonisation, both native fish and P. semilunaris occupied similar niches (i.e. microhabitats) to those occupied before colonisation. While niche use of YOY N. melanostomus and P. semilunaris overlapped significantly, YOY native fish utilised different habitats from the gobiids. We suggest that N. melanostomus did not compete for resources with YOY fish in our study area due to lack of niche overlap and/or surplus resources. As N. melanostomus rapidly dominated the fish assemblage at our site, we further suggest that utilisation of an empty niche, rather than competitive superiority, was the main factor facilitating its success.     

Suppression of Settlement of Larvae of Fouling Organism by Water-Soluble Substances from Epibiotic Bacteria

Twenty-nine bacterial strains were isolated from the surface of the green alga Ulva reticulata, the soft coral Dendronephthya sp., and the sponge Haliclona sp. The bacterial species Vibrio alginolyticus, Vibrio sp. 4, an unidentified α-Proteobacterium, Vibrio sp. 7, Pseudoalteromonas sp. 2, and Pseudoalteromonas sp. 4 were found to suppress the larval settlement of the polychaete Hydroides elegans (Haswell, 1883) and the bryozoan Bugula neritina (Linnaeus, 1758). Aqueous extracts of five bacteria (all those named above except Pseudoalteromonas sp. 2) prevented larval settlement. Bacteria V. alginolyticus, Vibrio sp. 4, and an unidentified α-Proteobacterium were first discovered to produce high-molecular substances (>100 kDa) preventing larval settlement. Their activity was inhibited by amylase treatment, while trypsin and papain did not influence their activity. The data obtained proved that bacteria from the surface of the number of marine organisms excrete water-soluble sacchariferous compounds preventing larval settlement.     

Reproductive interference between two serious pests,oriental fruit flies <Emphasis Type="Italic">Bactrocera carambolae</Emphasis> and <Emphasis Type="Italic">B. dorsalis</Emphasis> (Diptera: Tephritidae), with very wide but partially overlapping host ranges

Bactrocera carambolae and B. dorsalis (Diptera: Tephritidae) are extremely destructive pests of fruits and vegetables in the Asia-Pacific region. Earlier reports have described that B. carambolae and B. dorsalis, respectively, use mainly star fruit and mango, suggesting a certain level of host partitioning which can be ascribed neither to differences in larval food qualities nor host-specific parasitoid mortality. This study specifically examined reproductive interference (antagonistic sexual interaction) between B. carambolae and B. dorsalis as a potential factor strongly affecting their host partitioning. We observed mating behaviors, especially interspecific courtships and mating, by cohabiting the conspecific and heterospecific pairs together. Consequently, we quantified their effects on the reproductive success of females. Males of both species frequently courted their own females, but they also courted females of other species. Courtship refusal by females was not selective in males of either species. This incomplete discrimination of both sexes led to frequent occurrences of interspecific sexual interactions in both species, but only B. carambolae females showed reduced reproductive success. These results suggest that B. dorsalis, superior in reproductive interference, can occupy high-quality mango, whereas B. carambolae, inferior in reproductive interference, must use low-quality star fruit.     

Early ontogeny of the mackerel icefish, Champsocephalus gunnari, in the southern Scotia Arc

During the early ontogeny of fishes, the timing and duration of key events such as larval hatching and the switch from endogenous to exogenous feeding largely determine the offspring viability and survival. The aim of the present study was to investigate the life history traits of the early larvae of the mackerel icefish, Champsocephalus gunnari, collected in summer south of the South Shetland Islands in the Bransfield Strait and north of Elephant Island. Through the analysis of sagittal otolith microstructure, we assessed the timing and duration of egg incubation, larval hatching, first exogenous feeding, rate of yolk resorption and body growth rate. Compared to populations living further north (i.e. around South Georgia and Kerguelen Islands), mackerel icefish in the southern Scotia Arc exhibits longer egg incubation (lasting 90–120 days from winter to summer) and delayed hatching time spread over a relatively short period lasting 26 days between January and February. The first exogenous feeding takes place between 13 and 24 days after hatching still in the presence of the yolk-sac, indicating a prolonged mixed feeding afterward. The specific growth rate or daily percentage change in size (G) was 1.9 % SL day^?1, corresponding to a daily growth rate at mean size of 0.31 mm day^?1. While showing significant differences in early life history traits across their geographical distribution, C. gunnari populations share a common strategy, spawning a small number of large eggs that hatch in relatively large-sized larvae, at a time which may be independent of the timing of pack-ice retreat and onset of the production cycle.     

Ecology of inshore notothenioid fish from the Danco Coast,Antarctic Peninsula

A total of 1,103 inshore notothenioid fish were caught by means of trammel-nets in 4 sites surrounding Cierva Point (Moss Island 1; Moss Island 2; Sterneck Island; Leopardo Island), Danco Coast, West Antarctic Peninsula, during February and March 2000. The families Nototheniidae, Channichthyidae and Bathydraconidae were represented in the samples, Notothenia coriiceps being the dominant fish of the area. Gobionotothen gibberifrons and Trematomus newnesi followed in importance. In general, the fish sampled agreed in terms of number and mass with those of the South Shetland Islands area, except for a marked higher occurrence of G. gibberifrons in the Danco Coast. This supports the hypothesis that the commercial fishery around the South Shetland Islands at the end of the 1970s was responsible for the decrease in the inshore population of G. gibberifrons in that area during the last 17 years. Information on morphometry, reproduction and diet of the fish species caught is provided.     

Modeling vertical coral connectivity and mesophotic refugia

Whether mesophotic reefs will behave as refugia for corals threatened by global climate change and coastal development depends on vertical exchange of larvae between diverse habitats. Here we use a biophysical model of larval dispersal to estimate vertical connectivity of a broadcasting (Orbicella faveolata) and a brooding (Porites astreoides) species of coral in the US Virgin Islands. Modeling predicts subsidy to shallow areas by mesophotic larvae of both species based on local hydrology, adult reproductive characteristics, larval traits, and a wide range of scenarios developed to test depth-sensitive factors, such as fertilization rates and post-settlement survivorship. In extreme model scenarios of reduced fertilization and post-settlement survivorship of mesophotic larvae, 1–10 % local mesophotic subsidy to shallow recruitment is predicted for both species, which are demographically significant. Although direct vertical connectivity is higher for the broadcaster, the brooder demonstrates higher local multigenerational vertical connectivity, which suggests that local P. astreoides populations are more resilient than those of O. faveolata, and corroborates field studies. As shallow habitat degrades, mesophotic–shallow subsidy is predicted to increase for both species. This study is the first of its kind to simulate larval dispersal and settlement between habitats of different depths, and these findings have local, regional, and global implications for predicting and managing coral reef persistence in a changing climate.     

New and rare snailfishes (Liparidae,Scorpaeniformes) with the description of four new species from the Southern Hemisphere and tropical east Pacific

New and rare liparid fishes (Liparidae, Scorpaeniformes) are found and described. Careproctus armatus Andriashev, 1991 sampled off the South Sandwich Islands (at a depth 2281–2369 m); it is the second record of the species. Four species are collected in the vicinity of the South Shetland Islands: Careproctus parini Andriashev et Prirodina, 1990 (off King George Island, 573–861 m), Paraliparis meganchus Andriashev, 1982 (off Elephant Island, 559 m), P. monoporus Andriashev et Neyelov, 1979 (off Elephant Island, 559 m) and Paraliparis specimens, most similar to P. tompkinsae Andriashev, 1992 (off King George Island, 766–861 m). Paraliparis charcoti Duhamel, 1992 recorded at the eastern part of the Weddell Sea (475–633 m). Paraliparis, most similar to P. tetrapteryx Andriashev et Neelov, 1979, found in the Southwestern Atlantic (1200 m). Four new species are described. Paraliparis porcus sp. nov. based on one male SL 85 mm from off the South Shetland Islands (Elephant Island, 332–374 m). Paraliparis acutidens sp. nov. described from the juvenile SL 115 mm, sampled in the western part of the Scotia Sea (3721–3723 m). Paraliparis kocki sp. nov. known from 3 adults caught in the depression of the Bransfield Strait (1914–1920 m), isolated from the Weddell Sea by shallower waters. The only specimen of the Paraliparis mexicanus sp. nov. collected in the tropical Pacific off Mexico at depth not more than 900 m.