Ostracoda in Lake Illawarra: Environmental factors, assemblages and systematics.

1987 ◽  
Vol 38 (6) ◽  
pp. 795 ◽  
Author(s):  
I Yassini ◽  
BG Jones

Major controls of the distribution pattern and abundance of living ostracod populations in Lake Illawarra, a coastal lagoon south of Wollongong, New South Wales, are salinity and the benthic flora. The biocenotic ostracod assemblage from the intertidal zone around Windang Island is a typical, diverse, upper sublittoral, open ocean fauna. The lake entrance channel, which is a transport corridor for marine sediments into the lagoon, has a restricted ostracod biocenose (14 species) but contains an additional 72 species in the diverse thanatocenose resulting from the mixing of estuarine and marine species. Within the lagoon, the benthic flora influences the ostracod distribution pattern with the most diverse assemblage (13 species) occurring in areas covered by seagrasses. Seagrass distribution is, in turn, controlled by water depth, circulation, turbidity and substrate. Estuarine ostracods associated with the seagrass beds can tolerate florally induced fluctuations in pH from 7 to 10 and in dissolved oxygen from 1 mg l-1 to 14 mg l-1. In the deeper parts of the lagoon with a predominantly mud substrate, the ostracod assemblage is dominated by Osticythere reticulata. Most samples retrieved from the most polluted part of the lagoon contained no ostracods. A total of 90 ostracod species and subspecies belonging to 50 genera has been identified; nine species: Cytheralison cosmetics, Callistocythere janiceburrowsae, Callistocythere windangensis, Neocytherideis anneclarkeae, Actinocythereis robustus, Bradleya rectangulata, Procythereis jonesi, Hemicytherura windangensis and Cytheropteron wrighti; and one subspecies, Callistocythere dorsotuberculata paucicostata, are described as new to science.

1995 ◽  
Vol 46 (8) ◽  
pp. 1181 ◽  
Author(s):  
I Yassini ◽  
BG Jones ◽  
RJ King ◽  
M Ayress ◽  
KT Dewi

Sublittoral kelp forests, such as those occupying the wave-dominated shallow marine rocky substrata around Windang Island, New South Wales, provide an important habitat for ostracods. This is reflected in the diverse biocoenotic assemblage (69 species, including one new genus and three new species) and populations of juveniles recorded from this area. The thanatocoenotic assemblage contributes a further 37 ostracod species. The total assemblage is more diverse than, and has only 17 species in common with, the previously documented intertidal biocoenotic assemblages around Windang Island. The distribution of the more abundant ostracod species reflects the energy levels within the environment, with a greater proportion of smooth-shelled forms occurring in the higher-energy zones at shallow depths. Most of the thanatocoenose population represents species moved up from the deeper shelf or into the region from the adjacent tidal channel into Lake Illawarra, rather than species from the intertidal region around Windang Island.


2006 ◽  
Vol 21 (2) ◽  
pp. 217 ◽  
Author(s):  
Bryan E. Chenhall ◽  
Brian G. Jones ◽  
Craig R. Sloss ◽  
Mark O'Donnell ◽  
Marrack Payne ◽  
...  

2006 ◽  
Vol 21 (2) ◽  
pp. 228 ◽  
Author(s):  
Paul L. Brown ◽  
Vincent J. Carolan ◽  
Deborah J. Hafey ◽  
Machiko Iko ◽  
Scott J. Markich ◽  
...  

1967 ◽  
Vol 15 (6) ◽  
pp. 1163 ◽  
Author(s):  
WH Ewers

A morph-frequency cline and a size cline are described for the snail Velacumantus australis. The frequency of a white-banded form decreases clinally with latitude South. Living populations from Queensland and northern New South Wales have frequencies between 7 and 18% whereas all populations from southern New South Wales and eastern Victoria, except those from Lake Illawarra, have frequencies between 2 and 5%. The frequency in Port Phillip Bay is less than 0.1%. The frequency in a sample from Swan River, Western Australia, was 9.1% about the same as in samples from localities of the same latitude on the eastern coast of Australia. The frequency in most fossil samples was similar to that in nearby living populations. The mean length of populations from the eastern states increases clinally with increase in latitude South, although there are some irregular fluctuations between adjacent populations which are probably influenced by population density.


2019 ◽  
Vol 46 (8) ◽  
pp. 701 ◽  
Author(s):  
Paul A. Butcher ◽  
Toby P. Piddocke ◽  
Andrew P. Colefax ◽  
Brent Hoade ◽  
Victor M. Peddemors ◽  
...  

Abstract ContextA series of unprovoked shark attacks on New South Wales (Australia) beaches between 2013 and 2015 triggered an investigation of new and emerging technologies for protecting bathers. Traditionally, bather protection has included several methods for shark capture, detection and/or deterrence but has often relied on environmentally damaging techniques. Heightened environmental awareness, including the important role of sharks in the marine ecosystem, demands new techniques for protection from shark attack. Recent advances in drone-related technologies have enabled the possibility of real-time shark detection and alerting. AimTo determine the reliability of drones to detect shark analogues in the water across a range of environmental conditions experienced on New South Wales beaches. MethodsA standard multirotor drone (DJI Inspire 1) was used to detect shark analogues as a proxy during flights at 0900, 1200 and 1500 hours over a 3-week period. The 27 flights encompassed a range of environmental conditions, including wind speed (2–30.0kmh−1), turbidity (0.4–6.4m), cloud cover (0–100%), glare (0–100%), seas (0.4–1.4m), swells (1.4–2.5m) and sea state (Beaufort Scale 1–5 Bf). Key resultsDetection rates of the shark analogues over the 27 flights were significantly higher for the independent observer conducting post-flight video analysis (50%) than for the drone pilot (38%) (Wald P=0.04). Water depth and turbidity significantly impaired detection of analogues (Wald P=0.04). Specifically, at a set depth of 2m below the water surface, very few analogues were seen by the observer or pilot when water turbidity reduced visibility to less than 1.5m. Similarly, when water visibility was greater than 1.5m, the detection rate was negatively related to water depth. Conclusions The present study demonstrates that drones can fly under most environmental conditions and would be a cost-effective bather protection tool for a range of user groups. ImplicationsThe most effective use of drones would occur during light winds and in shallow clear water. Although poor water visibility may restrict detection, sharks spend large amounts of time near the surface, therefore providing a practical tool for detection in most conditions.


1998 ◽  
Vol 20 (2) ◽  
pp. 287
Author(s):  
B.A. Ellem ◽  
A. Mcleod

McLeod (1993) monitored the movement of platypuses (Ornithorhynchus anatinus) using telemetric devices, recording the number of times animals were found in predetermined grid positions in a pool impounded behind the Duckmaloi Weir near Oberon, New South Wales, and the number of times they were discovered in numerous burrows on the periphery of the weir pool. The aim of this program was to identify the predictive variables that accounted for platypus movement from among those measured such as water depth, and from among known factors such as age. A Poisson regression model is described together with the results for these data. The potential benefits of Poisson regression models for these data over log transformation models, such as handling zeros and catering for overdispersion, are expounded. The analyses indicate that the use of areas of the weir pool were related to water depth, with there being greater use of shallow depths in the channel than in other locations in the pool. There was also differential usage of burrows in the banks of the pool related to different degrees of foliage density from one side of the weir pool to the other.


2006 ◽  
Vol 46 (4) ◽  
pp. 483 ◽  
Author(s):  
J. D. Hughes ◽  
I. J. Packer ◽  
D. L. Michalk ◽  
P. M. Dowling ◽  
W. McG. King ◽  
...  

Soil water, runoff amount and quality, pasture production and environmental data were measured for a pastoral prime lamb enterprise in the Central Tablelands of New South Wales from 1998 to 2002. There were 4 pasture treatments: fertilised and sown chicory (CH), fertilised and sown introduced pastures (SP), fertilised naturalised pastures (FN) and unfertilised naturalised pastures (UN). Two grazing management regimes, tactically grazed (TG) and continuously grazed (CG) were imposed on the SP, FN and UN treatments. The CH treatment was rotationally grazed. To compare pasture and grazing system water use, maximum soil water deficit values (SWDMax) were calculated from neutron moisture meter data. SWDMax was influenced by both environmental and management factors. Management factors that influenced SWDMax were herbage mass of perennials, degree of perenniality, and the perennial species present. Environmental factors accounted for >50% of the variation in SWDMax. Inclusion of management factors (perennial herbage mass of C3 and C4 species and percentage perennial herbage mass), accounted for an additional 16% of variation. While the influence of pasture management appears to be relatively small, importantly, management is the only avenue available to land managers for influencing SWDMax. The UNTG and all sown treatments, with greater perennial herbage mass or greater C4 herbage mass consistently produced the highest SWDMax. Runoff amount and quality data are presented for ground cover percentages which generally exceeded 80% for the experimental period. Runoff as a proportion of rain received during the experiment was <3%. Environmental factors explained 47% of variation in runoff, while pasture herbage mass and ground cover percentage explained an additional 2% of variation. Water quality was monitored on 3 treatments (SPTG, FNTG and UNCG) for total nitrogen (N), total phosphorus (P) and total suspended solids (TST) over a 6-month period. The mean values for total N and P were below the acceptable contaminant concentration for agricultural irrigation water. An important outcome of this research is the concept of a practical Targeted Water Management Plan (TWMP) which devises a framework for optimum water usage and productivity at a landscape scale.


1979 ◽  
Vol 30 (3) ◽  
pp. 387 ◽  
Author(s):  
MJ Conacher ◽  
WJR Lanzing ◽  
AWD Larkum

The fanbellied leatherjacket, M. chinensis, was found to ingest fresh seagrass as a major part of its diet. Other important food items were gammarid amphipods, carid shrimps and several species of epiphytic algae. All food items were of seagrass bed origin. Microscopic examination of gut contents suggested that seagrass and algae did not appear to be digested by the fish, but 14C-labelling of the plants showed that significant amounts of the labile carbon compounds were removed and assimilated during digestion. The fanbellied leatherjacket was found to feed in the seagrass beds during the day, probably relying on eyesight for detecting food. Variations in tide height did not seem to affect their feeding pattern. The amounts of seagrass, algae, amphipods and shrimps removed by M. chinensis in Quibray Bay were calculated and compared with the availability of each of these foods. Grazing by M. chinensis had little effect on seagrass and algae production rates and standing crops, but probably had a significant influence on carid shrimp and amphipod populations.


Sign in / Sign up

Export Citation Format

Share Document