Tropical inshore dolphins of north-western Australia: Unknown populations in a rapidly changing region.

2012 ◽  
Vol 18 (1) ◽  
pp. 56 ◽  
Author(s):  
Simon J Allen ◽  
Daniele D Cagnazzi ◽  
Amanda J Hodgson ◽  
Neil R Loneragan ◽  
Lars Bejder

Australian Snubfin Orcaella heinsohni, Indo-Pacific Humpback Sousa chinensis and Indo-Pacific Bottlenose Dolphins Tursiops aduncus inhabit Australia’s tropical north-western coastline, a region undergoing extensive port development associated with the massive expansion of the oil, gas and mining industries. The current lack of data on dolphin population sizes or trends precludes impact assessments of developments on these protected species. Furthermore, the Western Australian and Commonwealth Government conservation listings of tropical inshore dolphins do not reflect their international listings. From April to July, 2010, we conducted ad hoc boat-based surveys (n=55) of inshore delphinids at seven sites across north-western Australia from Coral Bay in the south (23.1°S: 113.8°E) to Cable Beach in the north (17.9°S: 122.2°E). We documented the locations of these three species from which we obtained photoidentification and biopsy data, as well as reports of Australian Snubfin Dolphin sightings from researchers and community groups. The data from this limited field effort confirm that Indo-Pacific Humpback and Indo-Pacific Bottlenose Dolphins occur in the waters adjacent to each north-western Australian urban centre and show that the range of the Australian Snubfin Dolphin extends considerably further south-west than previously reported. Given the scale of coastal developments and the vulnerability of isolated cetacean populations to fragmentation or extirpation, assessments of the viability of dolphin populations are required. Our data suggest that the Australian Snubfin, Indo-Pacific Humpback and Indo-Pacific Bottlenose Dolphins need to be considered as likely to be impacted by coastal developments across north-western Australia.

1985 ◽  
Vol 36 (2) ◽  
pp. 247 ◽  
Author(s):  
SJM Blaber ◽  
JW Young ◽  
MC Dunning

The species composition and broad trophic structure of the mangrove creek and open shore fish communities of the Dampier region in tropical north-western Australia are described. The habitats are characterized by a lack of freshwater influence, low turbidity and a tidal range in excess of 4 m. Both mangroves and open shores have a diversity of species typical of Indo-west Pacific coastal waters but the physical conditions have modified the community structure both to exclude many families that prefer areas of higher turbidity and reduced salinity, and to include others that usually occur only in clear waters. The fish faunas of the mangroves (113 species) and open shores (106 species) are compared: 54 species were common to both. The deeper waters were dominated by piscivores, which penetrated throughout the mangroves at high tide. Iliophagous species were abundant, particularly in the mangroves where the organic content of the substratum (7.8-8.2%) was not reduced markedly compared with other areas of the Indo-Pacific, despite the lack of freshwater inflow. The clear and deep water in the mangroves at high tide favour predation on juveniles by piscivorous fishes and reduce the effectiveness of such areas as nurseries. There is virtually no overlap of the fauna with that of the deeper waters (>20 m) of the North West Shelf, and the inshore region is not a significant nursery ground for any of the commercially important deeper water species.


Zootaxa ◽  
2009 ◽  
Vol 2059 (1) ◽  
pp. 51-68 ◽  
Author(s):  
TOMISLAV KARANOVIC ◽  
STEFAN M. EBERHARD

A new species of the genus Speleophria is described from a cave in the Nullarbor region in southern Western Australia. Its congeners include species from the Balearics, Croatia, Bermuda, Yucatan peninsula and north-western Western Australia, all considered to be Tethyan relicts. However, the discovery of the new speleophriid in the Nullarbor region has important biogeographic and ecological implications. From the biogeographic perspective, it either suggests dispersal as the process determining the current distribution pattern of the aquatic fauna found on the Roe Plains or significantly extends the Tethyan track across Australia, from the north-western coastal margin of the continent to the southern coastal margin. From an ecologic perspective, the new speleophriid suggests the possible existence of anchialine habitats in southern Australia. Speleophria nullarborensis sp. nov. can be distinguished from its four congeners by its plesiomorphic 3-segmented endopod of the first swimming leg (2-segmented in other species) and unusually long innermost apical seta on the caudal ramus. Another character that easily distinguishes our new species, and seems to be an autapomorphic feature, is its constricted preanal somite.


Oceania ◽  
1972 ◽  
Vol 42 (3) ◽  
pp. 223-238 ◽  
Author(s):  
C. G. von Brandenstein

2006 ◽  
Vol 57 (8) ◽  
pp. 837 ◽  
Author(s):  
Gavin Gouws ◽  
Barbara A. Stewart ◽  
Savel R. Daniels

Although phylogeographic patterns of freshwater decapods elsewhere in Australia are well documented, little is known of the phylogeography and biogeography of the endemic freshwater fauna of south-western Australia. Here, the phylogeographic structure of a freshwater crayfish, Cherax preissii Erichson, 1846, was investigated to determine contemporary and historical patterns of gene flow and to examined evolutionary and biogeographical scenarios. Allozyme and cytochrome c oxidase subunit I mitochondrial DNA data were collected from 15 populations, sampled across the known C. preissii distribution. Both markers revealed a clear distinction and separation among populations occurring in the north-western and southern portions of the distribution. Inferences of allopatric fragmentation and molecular dating attributed the divergence of the aquatic fauna of these regions to periods of Pliocene–Pleistocene aridity. Connectivity appeared to be greater within each of these regions. Evidence suggested contemporary, but not ongoing, gene flow, particularly within the southern region. This was possibly facilitated by dispersal during pluvial Pleistocene periods or drainage connectivity during episodic marine regressions. The divergence and distributions of these lineages parallels patterns seen in other freshwater crayfish of the region. More explicit investigation of these and further fine-scale phylogeographic studies may contribute to the understanding of biogeography and evolution in the south-west, and may further refine currently recognised biogeographical regions.


2008 ◽  
Vol 88 (6) ◽  
pp. 1153-1157 ◽  
Author(s):  
Bruno Díaz López ◽  
Julia Andrea Bernal Shirai ◽  
Alberto Bilbao Prieto ◽  
Paula Méndez Fernández

Solitary wild bottlenose dolphins and man frequenting the same small areas makes boat interaction more or less inevitable. Here we provide the first quantified data about solitary bottlenose dolphin diving behaviour in the presence and absence of boats. Over 110 hours were spent observing a solitary bottlenose dolphin within a 6 km2 bay on the north-western coast of Spain from April to August 2005. A generalized linear mixed model explaining 77.3% of the variability of duration of dives indicated that the animal did not vary its diving activity in function of the presence of boats. However, the length of dives was related with the behavioural events prior to dive. Dolphin activity was characterized by mean dive intervals (mean = 62.6 seconds) related to a predominance of foraging behaviour. Because of the frequent presence of boats and the manner in which they moved, the dolphin may have become accustomed to their presence. The data reported here could be used to implement precautionary management proposals that take into account the potential effects of boat presence on bottlenose dolphins.


2001 ◽  
Vol 41 (1) ◽  
pp. 497
Author(s):  
W.L. Tinapple

Petroleum exploration activity in Western Australia over the past decade has been on the increase, boosted by the positive results of many new discoveries, mainly on the North West Shelf but also in frontier areas. Significant discoveries in 1999–2000 resulted from new exploration concepts including deep plays in the Barrow/Dampier Sub-basins, heavy oil plays in the Carnarvon Basin, a deep-water gas play west of Gorgon, large gas/condensate plays in the Browse Basin, and a new gas play in the southern Bonaparte Basin. Discovery itself is a great incentive to the industry to further exploration; however, concerns over oil price, the Australian dollar, markets, policies and perceived prospectivity impact on exploration spending. The short-term outlook for WA is good as a result of existing work commitments including an average of 50 exploration wells to be drilled each year for the next three years. Onshore, where exploration has been subdued, there are signs of increased activity. The Western Australian government is playing a key role in promoting the State through gazettals, promotional activities— conferences and publications, acquiring precompetitive data and making petroleum data more accessible. The government funded Petroleum Exploration Initiatives program is continuing and efforts are being made to facilitate exploration. Sustained high oil prices, improvements in technology and efforts to expedite access to land are just some of the factors which will assist companies in their endeavours. In the longer term, continued growth in Western Australia’s petroleum industry is projected.


1969 ◽  
Vol 17 (1) ◽  
pp. 65 ◽  
Author(s):  
JAL Watson

Thirty species of Odonata are known to occur in the north-west of Western Australia, between the De Grey and Gascoyne Rivers. Eight of these species, from the families Coenagrionidae, Protoneuridae, Gomphidae, Corduliidae, and Libellulidae, belong to taxa here described as new. All the north-western dragonflies are either of tropical affinity, or widespread species. The species confined to permanent waters, i.e. to conditions of relatively mild temperatures and high oxygen tensions, are commonly more distinct from closest relatives in the Kimberley region or northern Queensland, than Kimberley and Queensland species are from each other. Such disjunct species show limited dispersal as adults.


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