scholarly journals Poorer breeding by little penguins near Perth, Western Australia is correlated with above average sea surface temperatures and a stronger Leeuwin Current

2012 ◽  
Vol 63 (10) ◽  
pp. 914 ◽  
Author(s):  
Belinda L. Cannell ◽  
Lynda E. Chambers ◽  
Ron D. Wooller ◽  
J. Stuart Bradley
Keyword(s):  
Western Australia ◽  
Breeding Success ◽  
Sea Surface ◽  
Laying Date ◽  
Breeding Period ◽  
Breeding Performance ◽  
Leeuwin Current ◽  
Oceanographic Variables ◽  
Fledgling Success ◽  
Little Penguin

Using 20 years of data (1986 to 2008), we examined relationships between oceanographic variables (Fremantle sea level (FSL) – a proxy for the strength of the Leeuwin Current – and sea surface temperature (SST)) and five measures of little penguin, Eudyptula minor, breeding performance near Perth, Western Australia: namely (1) the laying date, (2) the number of chicks produced per pair, (3) the proportion of eggs that hatched, (4) the overall breeding success, defined as the proportion of total eggs laid that resulted in successful fledglings and (5) chick mass at fledging. The next three years of data (2009 to 2011) were used to test the performance of our statistical predictive models. FSL provided more accurate predictions of timing of laying, whereas SST provided more accurate predictions of breeding success. A later end to laying was associated with a high FSL during the summer (December to February) before breeding. Higher SSTs in the pre-breeding period from April to May corresponded to reduced breeding success, with lower fledgling success, fewer chicks per pair and generally a lower mean mass of chicks at fledging. The models predict that future oceanographic warming is expected to reduce the breeding success of this colony of little penguins.

Effect of the Leeuwin Current upon sea surface temperatures off south-western Australia

1984 ◽  
Vol 35 (4) ◽  
pp. 487 ◽  
Author(s):  
DJ Rochford
Keyword(s):  
Western Australia ◽  
Coastal Waters ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
Leeuwin Current ◽  
South Eastern ◽  
Surface Temperatures ◽  
Autumn And Winter

Comparison of long-term mean monthly sea surface temperatures of coastal waters at comparable latitudes off south-eastern and south-westem Australia shows that, during the duration of the Leeuwin Current in autumn and winter, sea surface temperatures are 1-3�C higher off south-western Australia.

scholarly journals Inferred predation of Fairy Tern eggs by Ruddy Turnstones at Rottnest Island, Western Australia, an internationally significant shorebird site

2021 ◽  
Vol 38 ◽  
pp. 115-117
Author(s):  
C.N. Greenwell ◽  
◽  
Keyword(s):  
Biodiversity Conservation ◽  
Western Australia ◽  
Breeding Success ◽  
Behavioural Response ◽  
Environment Protection ◽  
Egg Predation ◽  
Breeding Colony ◽  
Wide Range ◽  
Collective Group ◽  
The Tropics

Ruddy Turnstones Arenaria interpres have been identified as egg-predators at seabird and shorebird colonies, including gull and tern colonies in the tropics and Northern Hemisphere. The Australian Fairy Tern Sternula nereis nereis is a threatened (Environment Protection and Biodiversity Conservation Act 1999: Vulnerable) coastal seabird, whose breeding behaviour and ecology expose it to a wide range of threats. This study describes inferred predation on Fairy Tern eggs at a small breeding colony on Rottnest Island, Western Australia, by Ruddy Turnstones, a previously unsuspected predator for thisspecies. Unlike the behavioural response shown towards Silver Gulls Larus novaehollandiae and Australian Ravens Corvus coronoides, which includes collective group defence and dive-bombing, Fairy Terns showed a lack of aggression towards Turnstones within the colony. The lack of a behavioural response suggests that the Terns did not recognise the Turnstones as predators, which may increase the risk of egg-predation. This study suggests that we should be alert to threats from unsuspected predators, which have the potential to reduce the breeding success of this Vulnerable tern.

The Primary Moult of Curlew SandpipersCalidris ferrugineain North-Western Australia Shifts According to Breeding Success

Ardea ◽  
2011 ◽  
Vol 99 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Yahkat Barshep ◽  
Clive Minton ◽  
Les G. Underhill ◽  
Magdalena Remisiewicz
Keyword(s):  
Western Australia ◽  
Breeding Success ◽  
North Western

Dynamics of the Ningaloo Current off Point Cloates, Western Australia

2006 ◽  
Vol 57 (3) ◽  
pp. 291 ◽  
Author(s):  
Mun Woo ◽  
Charitha Pattiaratchi ◽  
William Schroeder
Keyword(s):  
Numerical Model ◽  
Continental Shelf ◽  
Western Australia ◽  
Bottom Topography ◽  
Volume Transport ◽  
Relative Strength ◽  
Cross Sectional ◽  
Leeuwin Current ◽  
The North ◽  
Tropical Water

The Ningaloo Current (NC) is a wind-driven, northward-flowing current present during the summer months along the continental shelf between the latitudes of 22° and 24°S off the coastline of Western Australia. The southward flowing Leeuwin Current is located further offshore and flows along the continental shelf break and slope, transporting warm, relatively fresh, tropical water poleward. A recurrent feature, frequently observed in satellite images (both thermal and ocean colour), is an anti-clockwise circulation located offshore Point Cloates. Here, the seaward extension of the coastal promontory blocks off the broad, gradual southern shelf, leaving only a narrow, extremely steep shelf to the north. The reduction in the cross-sectional area, from the coast to the 50 m contour, between southward and northward of the promontory is ~80%. Here, a numerical model study is undertaken to simulate processes leading to the development of the recirculation feature offshore Point Cloates. The numerical model output reproduced the recirculation feature and indicated that a combination of southerly winds, and coastal and bottom topography, off Point Cloates is responsible for the recirculation. The results also demonstrated that stronger southerly winds generated a higher volume transport in the NC and that the recirculation feature was dependent on the wind speed, with stronger winds decreasing the relative strength of the recirculation.

Comparison of the Semtner and Chervin eddy-resolving global ocean model with LUCIE and satellite observations in the Leeuwin Current region

1996 ◽  
Vol 47 (3) ◽  
pp. 509 ◽  
Author(s):  
CJC Reason ◽  
AF Pearce
Keyword(s):  
Western Australia ◽  
Satellite Data ◽  
General Circulation ◽  
Maximum Velocity ◽  
Circulation Model ◽  
Ocean General Circulation Model ◽  
Global Ocean ◽  
Western Coast ◽  
Model Output ◽  
Leeuwin Current

Output from the Semtner and Chervin eddy-resolving global ocean general circulation model is compared with observations from the Leeuwin Current Interdisciplinary Experiment (LUCIE) and satellite data for the coastal waters of Western Australia. The model output is a snapshot over the domain 9-43�S, 90-120�E for a day in mid July 1987, which is during the season that the Leeuwin Current is expected to be well established along the western and southern coasts of Western Australia. Maximum Leeuwin Current velocities in the model are of the order of 60 cm s-1 and are found in the southern part of the current on the western coast and around into the Great Australian Bight. At depths below about 200 m, and centred near 400 m, there is an equatorward-flowing undercurrent with maximum velocity of order 25 cm s-1. Comparison of temperature and salinity cross-sections with LUCIE observations reveals that the model output for this day exhibits many realistic features. In particular, the model fields display a number of prominent meanders and eddies on the Leeuwin Current as well as further offshore. Consistent with observations, mesoscale features associated with the Leeuwin Current are concentrated between 25�S and the Cape Mentelle region; the flow in the northern part of the Leeuwin Current and the North West Shelf may be too weak to induce eddy-generating instabilities. Prominent in the model output are two large meanders on the Leeuwin Current between 25�S and 29�S and two anticyclonic eddies further downstream; features similar to these are evident in satellite data during winter 1987.

Corrigenda - The Leeuwin Current south of Western Australia

1993 ◽  
Vol 44 (2) ◽  
pp. 285 ◽  
Author(s):  
GR Cresswell ◽  
JL Peterson
Keyword(s):  
Western Australia ◽  
Leeuwin Current

Statistical features of the Oceanographic area off south-western Australia, obtained from Bathythermograph data

1986 ◽  
Vol 37 (4) ◽  
pp. 421 ◽  
Author(s):  
LJ Hamilton
Keyword(s):  
Mixed Layer ◽  
Mixed Layer Depth ◽  
Sea Surface ◽  
Temperature Fields ◽  
Surface Mixed Layer ◽  
Statistical Features ◽  
Layer Depth ◽  
Leeuwin Current ◽  
South West

A statistical analysis has been made of 26 years of bathythermograph (BT) data to 1980 for the south-west Australian area bounded by 30-35�s. and 110-115�E., a region influenced by the Leeuwin Current. The data indicate that a surface mixed layer exists all year round, with average depth 55 m and standard deviation 37 m. All but 2% of BT casts show a mixed-layer depth (MLD) less than 150 m. MLD are deepest in mid-year, particularly from July to September. Sea surface temperatures (SST) are significantly related to temperature values down to 200 m depth, especially in mid-year, for both eastern and western parts of the area separated by 113�E. Correlations of MLD with SST are significant only in the western part, and then only from January to March, and April to June. Long-term horizontally averaged temperature fields are broadly related through the water column from the surface to 200 m. All results indicate that, especially in mid-year, SST fields are related to subsurface temperature fields, which may be representative of flow structure. Seasonal differences exist between the eastern and western areas, caused by the Leeuwin Current.

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