New Zealand Journal of Marine and Freshwater Research abstracts
Intertidal communities in Doubtful Sound, New Zealand: changes over time
MICHELLE C. BOYLE
JOHN B. JILLETT
PHILIP V. MLADENOV
Department of Marine Science
University of Otago
P. O. Box 56
Dunedin, New Zealand
email: john.jillett@stonebow.otago.ac.nz
email: philip.mladenov@stonebow.otago.ac.nz
Abstract Intertidal communities of Doubtful Sound, New
Zealand, were surveyed in 1995 to establish the extent of changes since they
were first surveyed 30 years earlier, before the Manapouri power scheme was
completed in 1969. This scheme resulted in more than a 3-fold increase of
freshwater inflow to Doubtful Sound, through a tailrace to Deep Cove. Thickness
of the low salinity surface layer exceeded the tidal range and was greater at
high than low contemporary volumes of tailrace inflow. Intertidal habitats were
mostly steep shores of solid rock, little more than 2 m in vertical extent.
Freshwater run-off, groundwater seepage, and aspect to sun were all major
factors affecting the intertidal communities. Algae and lichens dominated shore
communities. Normally common invertebrates were scarce, especially molluscan
grazers. Major changes since the early 1960s included almost total
disappearance of
Hormosira banksii and exclusion of many other species
notably
Apophloea lyallii and
Elminius modestus to outer reaches
of the Sound.
Keywords intertidal communities; fiord; freshwater inflow;
Hormosira
M99059
Received 28 October 1999; accepted 17 March 2001
PDF file of entire paper: medium quality (781K); (scanned from paper original: notes about this process)
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