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:E185E205
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
cfur...@gmail.com
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