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@gmail.com