[MARMAM] New dolphin publications Australia

Christine Fury cfury10 at gmail.com
Wed Jul 20 17:20:18 PDT 2011


Hi MMers,

The following papers are now available from their 
perspective journals or you can email me for a pdf copy.

Fury CA, Harrison PL (2011) Seasonal variation 
and tidal influences on estuarine use by 
bottlenose dolphins (Tursiops aduncus). 
Estuarine, Coastal and Shelf Science 93:389-395

In order to show that dolphins use estuary 
habitats differently depending on the season and 
tidal state, possibly in response to prey 
distribution, temperature, risk of stranding and 
accessibility, Indo-Pacific bottlenose dolphins 
(Tursiops aduncus) were observed year-round 
during a 3-year study in the Clarence River 
estuary (CR) and Richmond River estuary (RR) in 
northern New South Wales, Australia. Peak dolphin 
sightings occurred during the spring season and 
one or 2h prior to high tide. The spatial 
distribution of the dolphins in each estuary was 
analysed using the distance in kilometres that 
the dolphins travelled upstream with seasons and 
tidal phase as determinants. A General Linear 
Model showed that in the CR the dolphin spatial 
distribution in the estuary was not determined by 
season (F=0.434, df=3, P=0.729) but was by tidal 
phase (F=9.943, df=3, P<0.001) and the 
interaction between season and tidal phase 
(F=3.398, df=9, P<0.002). However, in the RR the 
spatial distribution of the dolphin use of the 
estuary was not determined by either season 
(F=1.647, df=3, P=0.194) or tidal phase (F=0.302, 
df=3, P=0.824). In the CR, the spatial 
distribution of the dolphins was largest on high 
and flood tides. This pattern of spatial 
distribution may occur because the CR is a 
relatively shallow estuary and this increased 
spatial distribution may reflect a lower 
stranding risk and an increase in accessibility 
of shallow areas during periods of higher tide. 
These areas could also provide access to their 
preferred prey items of sea mullet (Mugil 
cephalus) and sand whiting (Sillago ciliata).

Fury CA, Harrison PL (2011) Impact of flood 
events on dolphin occupancy patterns. Marine Mammal Science 27:E185–E205

The aim of this study was to assess potential 
impacts of water quality changes associated with 
floods on the occupancy of Indo-Pacific 
bottlenose dolphins (Tursiops aduncus) in two 
subtropical estuaries in Australia.Boat-based 
surveys were conducted in the Clarence River 
estuary (CR) and Richmond River estuaries (RR) 
over 3 yr. Principal components analysis (PCA) 
showed that when the dolphins were absent
from the estuaries, three water quality 
components were extracted in the CR and two 
components in the RR. The PCA1 component included 
high loadings for salinity, turbidity, and pH for 
the CR (46%); and salinity, turbidity, pH, and 
dissolved oxygen (DO) for the RR (51%). 
Randomization tests showed that dolphins 
abandoned both estuaries at times of lower 
salinity, and during periods of higher
turbidity and of lower levels of pH and dissolved 
oxygen in the RR that were associated with 
floods. The time until dolphins returned to the 
estuary postflood depended on the length and 
severity of the flood, but generally dolphins 
were observed in waters with salinity levels
above 29ppt. Their delayed return postflood could 
be for their physiological health, or because 
their prey returned to the estuaries
under these higher salinity conditions, or more 
likely a combination of both factors.

Regards
Christine

Christine Fury, PhD
Marine Ecologist
PO Box 390 Kingston, Hobart, Tasmania 7050
Mobile 0408-264-330
Webpage: http://independent.academia.edu/ChristineFury
cfury10 at gmail.com
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