Temporal patterns in distributions of tropical fish larvae on the North West Shelf of Australia

2004 ◽  
Vol 55 (5) ◽  
pp. 473 ◽  
Author(s):  
A. Sampey ◽  
M. G. Meekan ◽  
J. H. Carleton ◽  
A. D. McKinnon ◽  
M. I. McCormick
Keyword(s):  
Southern Oscillation ◽  
Fish Larvae ◽  
Early Stage ◽  
Larval Survival ◽  
Zooplankton Biomass ◽  
Tropical Fish ◽  
North West ◽  
Larval Fishes ◽  
The North ◽  
Abundance And Diversity

Information on the temporal distributions of tropical fish larvae is scarce. Early stage larval fishes were sampled using towed bongo plankton nets at sites on the southern North West Shelf of Australia (21°49′S, 114°14′E), between October and February of 1997/98 and 1998/99. The first summer was characterised by El Niño–Southern Oscillation-driven upwelling and high primary productivity, whereas in the second summer water temperatures were warmer and primary production was lower. Benthic percoid shorefishes dominated surface assemblages in both summers and this pattern may be typical of tropical shelf environments.The abundance and diversity of larval fishes were lowest in October and increased from November through to February. Assemblages displayed weak cross-shelf patterns, with a few taxa being more abundant at inshore sites (e.g. monacanthids), whereas others were more abundant offshore (e.g. scombrids). Although the composition of assemblages remained relatively consistent, many taxa (e.g. pomacentrids and carangids) showed differences in abundance between summers. Multivariate analyses found no relationships between abundance patterns of larval fishes and biophysical variables, such as temperature, salinity, and zooplankton biomass. Thus, seasonal changes in abundance may reflect differences in the spawning activities of adult fishes and/or larval survival.

scholarly journals Patterns of clinical nail appearances in patients with cutaneous psoriasis

2017 ◽  
Vol 90 (1) ◽  
pp. 22-27
Author(s):  
Elena Mihaela Marina ◽  
Carolina Botar-Jid ◽  
Sorana Daniela Bolboaca ◽  
Iulia Ioana Roman ◽  
Corina Simona Senila ◽  
...  
Keyword(s):  
Age Of Onset ◽  
Early Stage ◽  
Severity Index ◽  
University Hospital ◽  
Joint Involvement ◽  
Early Stage Disease ◽  
North West ◽  
The North ◽  
Plaque Type ◽  
Nail Changes

Background and aims. Nail manifestations are often an overlooked aspect in psoriatic disease, cutaneous and joint involvement being far more often reported and investigated. The reported prevalence of nail changes varies in literature, specific fingernail clinical features having different degrees of occurrence. The aim of this study was to describe specific clinical patterns of fingernail alterations in adult patients with plaque-type psoriasis in a university hospital in the North-West of Romania.Methods. Clinical data of 35 patients with fingernail psoriasis were collected and analyzed. Psoriasis Area and Severity Index (PASI) and Nail Psoriasis Severity Index (NAPSI) scores were used to quantify disease extension in each patient.Results. PASI score proved linearly correlated with NAPSI score (p<0.05). The age of onset of fingernail psoriasis was positively correlated with age of onset cutaneous psoriasis (p<0.0001). Furthermore, the duration of cutaneous involvement and NAPSI proved significantly related (p<0.05). The third fingernail in the right hand and first fingernail in the left hand were in most of the cases severely affected. The most common observed nail pattern was pitting, followed by salmon patches and subungual hyperkeratosis.Conclusion. Important nail changes appear even in moderate forms of cutaneous psoriasis. Particular localization of specific fingernail psoriasis pattern enables the possibility of detecting early stage disease.

Spatial and temporal variation in precipitation at the start of the rainy season in tropical Australia

2010 ◽  
Vol 32 (2) ◽  
pp. 215 ◽  
Author(s):  
S. T. Garnett ◽  
G. Williamson
Keyword(s):  
Seed Germination ◽  
El Niño ◽  
Rainy Season ◽  
El Nino ◽  
Southern Oscillation ◽  
Temporal Trends ◽  
Spatial And Temporal Variation ◽  
Economic Implications ◽  
North West ◽  
The North

The patterns of rainfall early in the rainy season vary substantially across northern Australia, even in sites with the same annual average. This has biophysical and economic implications in terms of land and infrastructure management, resource availability and capacity, and access. Daily patterns in long-term rainfall records in Australia north of 23°S subject to regular monsoonal rainfall were compared with threshold levels for dryland and wetland seed germination, initiation of the growing season, patterns of gaps between early storms and the heaviness of the first falls, correlations between thresholds, spatial variation in correlation with the Southern Oscillation Index (SOI) and temporal trends in mean threshold dates. The earliest rains sufficient to cause seed germination or generate fresh fodder occur in the north-west of the Northern Territory with the average date being later to the south, east and west. Initial falls of the rainy season are heaviest, however, on Cape York Peninsula so that the time between first falls and saturation is shortest in the east. The probability of extended gaps between rainfall events increased from north to south. When the SOI is taken into account, no change in timing could be detected at the few sites with records of sufficient duration. However, because of changes in SOI frequency, rains are tending to start earlier in the drier parts of the north and north-west and later in the east. This may be because anthropogenic climate change is resulting in fewer classical El Niño Southern Oscillation events and more frequent El Niño Modoki climate anomalies.

Oceanographic scenario and fish larval distribution off Guinea-Bissau (north-west Africa)

2014 ◽  
Vol 95 (3) ◽  
pp. 435-452 ◽  
Author(s):  
M.P. Jiménez ◽  
R.F. Sánchez-Leal ◽  
C. González ◽  
E. García-Isarch ◽  
A. García
Keyword(s):  
Surface Waters ◽  
Larval Fish ◽  
Fish Larvae ◽  
Inner Shelf ◽  
North West ◽  
Guinea Bissau ◽  
Larval Distribution ◽  
Océanographic Survey ◽  
Continental Runoff ◽  
Abundance And Diversity

This paper describes the hydrography and the larval fish assemblage of Guinea Bissau waters, and analyses the spatial distribution of the main families in relation to the oceanographic features of the area. Data were obtained during an oceanographic survey, undertaken between October and November 2008. In addition to 98 demersal fishing hauls, a total of 33 stations, located between 20 and 1000 m depth, were sampled for hydrography and ichthyoplankton. Data showed that Guinea-Bissauan surface waters are characterized by a strong thermohaline front that flows parallel to the bathymetry of the area. Warm surface waters (SST > 29°C) occupy the inner shelf, and colder (SST < 26°C), chlorophyll-a-rich waters take over the shelf break. Continental runoff seems responsible for the low salinity of the inner-shelf waters whereas the colder types bear thermohaline features typical of tropical Atlantic waters. These features define a scenario which favours the development of fish early life stages, reflected in the high abundance and diversity of fish larvae recorded. A total of 84 taxa of fish larvae were identified. Only the family Clupeidae accounted for 54.8% of the sampled larvae. Other important families were Carangidae (8.8%), Sparidae (8.4%) and Myctophidae (5.9%).

GEOLOGICAL FRAMEWORK OF THE GREAT AUSTRALIAN BIGHT

1969 ◽  
Vol 9 (1) ◽  
pp. 60
Author(s):  
R. Smith ◽  
P. Kamerling
Keyword(s):  
Middle Eocene ◽  
Early Stage ◽  
Upper Jurassic ◽  
The South ◽  
The West ◽  
Offshore Area ◽  
North West ◽  
Carbonate Sedimentation ◽  
The North ◽  
Great Australian Bight

Geophysical exploration carried out in the Great Australian Bight since 1966, combined with geological fieldwork in the adjacent land areas, has made it possible to outline the broad geological framework of the area.The "basement" consists of two major units, an offshore extension of the locally metamorphic Cambrian Kanmantoo Group in the south-east and the extension of the West Australian Archaean shield in the north-west. The boundary is thought to follow a trend extending westerly from the Cygnet-Snelling fault zone on Kangaroo Island.In two areas the basement has been downfaulted, thus creating depositional areas for thick sequences of sediments, namely the Elliston trough to the west of Eyre Peninsula and the Duntroon basin, south of Eyre Peninsula and west of Kangaroo Island.The geological setting of the Duntroon basin appears to be comparable with the Otway basin and a Jurassic- Cretaceous age is assumed for the folded sequence of sediments overlying the basement and underlying the Tertiary with angular unconformity. The basin was possibly partially and temporarily closed to the south and open to marine influences from the west.In the Elliston trough the lower part of the section which has low to medium velocity seismic character, is probably Mesozoic, as is evidenced by the Upper Jurassic encountered in its onshore extension. Proterozoic-Cambrian sediments may overlie the basement in the eastern part of the trough. Deformation of the Mesozoic is limited to the mouth of the trough where there is indication of a base- Tertiary unconformity. This trough was probably also open to marine influences to the west.Along the continental margin between the basins and also south of the Eucla basin a thin Mesozoic section, conformably underlying the Tertiary, is probably present, gradually thickening towards the continental slope.In the onshore area Tertiary sedimentation started with local deposition of clastics during the Middle Eocene, which also may have been the case off the Eucla basin, in the Elliston trough and in the Duntroon basin. Carbonate sedimentation took place from the Middle-Upper Eocene onwards, to reach its widest areal extent during the Lower Miocene. A hiatus during the Oligocene may have occurred in the western part of the Bight as is the case in the Eucla basin.Only weak deformation of the Tertiary in the offshore area has been observed. This generally occurs over Mesozoic structures in the Duntroon basin and as draping over topographic basement highs at the mouth of the Elliston trough.No significant hydrocarbon indications are known from the surrounding land areas, but the well-documented bitumen strandings along the coast point to offshore seepages indicating generation of hydrocarbons in the general area.At this stage prospects must be regarded as speculative.although a folded probable Mesozoic sequence forms an objective in the Duntroon basin while prospective Mesozoic-Tertiary section appears to be present in the Elliston trough, where structural evaluation is still at a relatively early stage.

Corrigendum to: Ocean currents and the larval phase of Australian western rock lobster, Panulirus cygnus

2002 ◽  
Vol 53 (3) ◽  
pp. 731 ◽  
Author(s):  
David A. Griffin ◽  
John L. Wilkin ◽  
Chris F. Chubb ◽  
Alan F. Pearce ◽  
Nick Caputi
Keyword(s):  
Transport Model ◽  
Early Stage ◽  
Larval Survival ◽  
Ocean Currents ◽  
Larval Transport ◽  
Offshore Wind ◽  
Larval Phase ◽  
Leeuwin Current ◽  
The North ◽  
Panulirus Cygnus

The return of Panulirus cygnus larvae to the coast of Western Australia after nearly a year at sea and its modulation by ocean currents were addressed with an individual-based larval-transport model. The simulations implied that offshore wind-driven transport of larvae is balanced by onshore geostrophic flow. Additional simulations revealed that vertical migration behaviour was essential to larval survival through its impact on advection. The six years simulated include two of high, two of low, and two of average puerulus settlement. The most robust interannual difference of the simulations was that, when coastal sea level was low and the Leeuwin Current was weak, more early-stage larvae were lost to the north and west under the influence of the wind. Conversely, many late-stage model larvae were carried south of the fishery in years when the Leeuwin Current was strong. The fraction of model larvae remaining or arriving offshore of the fishery and metamorphosing was essentially constant from year to year, so the variation in observed puerulus settlement was not explained by the model. The results imply that the nonadvective effects of fluctuations in the Leeuwin (e.g., on temperature and primary production) were primarily responsible for the high variation in natural settlement.

Ocean currents and the larval phase of Australian western rock lobster, Panulirus cygnus

2001 ◽  
Vol 52 (8) ◽  
pp. 1187 ◽  
Author(s):  
David A. Griffin ◽  
John L. Wilkin ◽  
Chris F. Chubb ◽  
Alan F. Pearce ◽  
Nick Caputi
Keyword(s):  
Transport Model ◽  
Early Stage ◽  
Larval Survival ◽  
Ocean Currents ◽  
Larval Transport ◽  
Offshore Wind ◽  
Larval Phase ◽  
Leeuwin Current ◽  
The North ◽  
Panulirus Cygnus

The return of Panulirus cygnus larvae to the coast of Western Australia after nearly a year at sea and its modulation by ocean currents were addressed with an individual-based larval-transport model. The simulations implied that offshore wind-driven transport of larvae is balanced by onshore geostrophic flow. Additional simulations revealed that vertical migration behaviour was essential to larval survival through its impact on advection. The six years simulated include two of high, two of low, and two of average puerulus settlement. The most robust interannual difference of the simulations was that, when coastal sea level was low and the Leeuwin Current was weak, more early-stage larvae were lost to the north and west under the influence of the wind. Conversely, many late-stage model larvae were carried south of the fishery in years when the Leeuwin Current was strong. The fraction of model larvae remaining or arriving offshore of the fishery and metamorphosing was essentially constant from year to year, so the variation in observed puerulus settlement was not explained by the model. The results imply that the nonadvective effects of fluctuations in the Leeuwin (e.g., on temperature and primary production) were primarily responsible for the high variation in natural settlement.

scholarly journals Survival of pacific salmons in the North Pacific in winter-spring season

2016 ◽  
Vol 185 (2) ◽  
pp. 67-94
Author(s):  
Svetlana V. Naydenko ◽  
Olga S. Temnykh
Keyword(s):  
Food Supply ◽  
Negative Influence ◽  
Zooplankton Biomass ◽  
Fish Mortality ◽  
Life Strategy ◽  
Winter Mortality ◽  
Feeding Intensity ◽  
North West ◽  
The North ◽  
Cyclic Changes

Influence of several factors (water temperature, food supply, predatory, size of juveniles) on pacific salmons survival during wintering is considered on the data collected from the upper pelagic layer in surveys conducted by Pacific Fisheries Research Center (TINRO) in the North-West Pacific. There is highly unlikely that the temperature influences on fish mortality directly. There is no obvious proof of negative influence of the low temperature on food base of salmons, as well. The lowering of forage zooplankton biomass in the Subarctic Front zone in February-March is insufficient for the salmons starvation taking into account that the total abundance of planktivorous nekton is also lowered in this area and generally in the Subarctic waters in winter-spring, so the food supply cannot be considered as a crucial factor of the salmons survival. Seasonal changes with lowering of feeding intensity, lipid accumulation, and somatic growth in winter known for pacific salmons aren’t forced by poor food base but are a feature of their species-specific life strategy with cyclic changes of metabolism. Predators are not abundant in the Subarctic zone in winter, so the predatory also cannot cause the high mortality of salmons. Relationship between the size of juveniles and their mortality in winter is considered in detail for the Okhotsk Sea stocks of pink salmon and there is concluded that the size of juveniles cannot be a predictor of their year-classes return for spawning. Thus, any single factor doesn’t determine winter mortality of pacific salmons but their survival is likely determined by a complex interaction of abiotic and biotic factors.

scholarly journals ENSO feedback drives variations in dieback at a marginal mangrove site

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. M. Hickey ◽  
B. Radford ◽  
J. N. Callow ◽  
S. R. Phinn ◽  
C. M. Duarte ◽  
...  
Keyword(s):  
Sea Level ◽  
Southern Oscillation ◽  
World Heritage Site ◽  
Range Limit ◽  
Tropical Regions ◽  
North West ◽  
Remote Sensing Classification ◽  
The North ◽  
Canopy Area ◽  
Landsat Satellite

AbstractOcean–atmosphere climatic interactions, such as those resulting from El Niño Southern Oscillation (ENSO) are known to influence sea level, sea surface temperature, air temperature, and rainfall in the western Pacific region, through to the north-west Australian Ningaloo coast. Mangroves are ecologically important refuges for biodiversity and a rich store of blue carbon. Locations such as the study site (Mangrove Bay, a World Heritage Site within Ningaloo Marine Park and Cape Range National Park) are at the aridity range-limit which means trees are small in stature, forests small in area, and are potentially susceptible to climate variability such as ENSO that brings lower sea level and higher temperature. Here we explore the relationship between mangrove dieback, and canopy condition with climatic variables and the Southern Oscillation Index (SOI)—a measure of ENSO intensity, through remote sensing classification of Landsat satellite missions across a 29 year period at a north-west Australian site. We find that the SOI, and seasonal mean minimum temperature are strongly correlated to mangrove green canopy (as indicator of live canopy) area. This understanding of climate variations and mangrove temporal heterogeneity (patterns of abundance and condition) highlights the sensitivity and dynamics of this mangrove forest and recommends further research in other arid and semi-arid tropical regions at mangrove range-limits to ascertain the extent of this relationship.

Zooplankton Abundance in Australasian Waters

1962 ◽  
Vol 13 (2) ◽  
pp. 106 ◽  
Author(s):  
DJ Tranter
Keyword(s):  
West Coast ◽  
Zooplankton Biomass ◽  
Open Ocean ◽  
Zooplankton Abundance ◽  
Sargasso Sea ◽  
North West ◽  
The North ◽  
South Wales ◽  
Tasman Sea ◽  
Upwelling Area

The seas surrounding Australia contain a relatively low zooplankton biomass, particularly in the open ocean. There is a region of higher biomass in an upwelling area between the north-west coast of Australia and Indonesia, and there are indications that there may be a shortlived spring increase in the southern Tasman Sea; otherwise, the biomass of zooplankton in the open ocean is no higher than in the Sargasso Sea. An examination of values for other parts of the world reveals that subtropical regions of the open ocean are characteristically poor in plankton. The mean zooplankton biomass on the Australian continental shelf was estimated to be about 100 mg/m³ (exclusive of salp swarms), varying from 82 to 213 mg/m³ with the area and the year. The biomass in the upwelling area south of Java was of the same magnitude, but in most parts of the open ocean it was no greatsr than 50 mg/m³, and was usually less than 25 mg/m³. Salp swarms were found more commonly in the southern part of the area investigated, and constituted local concentrations of higher biomass. These swarms took place in sprlng and summer and led to a seasonal cycle in the biomass level on the shelf regions of the New South Wales south coast. An increased biomass was also observed off the north-west coast of Australia during the period of prevailing offshore winds. This was crustacean in character.

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