New Zealand Journal of Marine and Freshwater Research abstracts
Estimating spatial scale of post-settlement transport potential of Macomona
liliana on an intertidal sandflat
Erin T. Petuha1
Carolyn J. Lundquist2
Conrad A. Pilditch1
1 Department of Biological Sciences
University of Waikato
Private Bag 3105
Hamilton, New Zealand
2 National Institute of Water and Atmospheric
Research Limited
P.O. Box 11 115
Hamilton, New Zealand
email: c.lundquist@niwa.co.nz
Abstract We estimated juvenile transport distance of a common New Zealand
bivalve, Macomona liliana, as a function of size, dispersal mode (bedload or
water column), and hydrodynamic forcing by combining laboratory (flume and settling
chamber) and field (tidal current) data. Live juvenile transport at 7.0 cm s–1
flow speed was significantly less than at 17.2 and 28.0 cm s–1 and most
juveniles (80–95%) were transported as bedload. The relationship between
juvenile size and fall velocity was positive, and byssus threads significantly
reduced fall velocity (≤30%). Our model showed that drifting juveniles can
potentially travel much further during a tidal cycle (spring tide 3.3 km, neap
tide 2.0 km) than those in the bedload (<80 m). When juvenile fall velocity
was added to the model, reducing time in the water column, transport distance
decreased considerably (0.6–50.3 m) compared to juveniles that drift for
the entire tidal period. Our results indicate a range of likely distances for
post-settlement transport of juvenile bivalves, important for predicting recolonisation
of disturbed areas and restoration of shellfish beds.
Keywords bivalve; Manukau Harbour; New Zealand; dispersal potential; bedload
transport; water column transport; flume; settling chamber
New Zealand Journal of Marine and Freshwater Research, 2006, Vol. 40: 487–502
0028–8330/06/4003–0487 © The Royal Society of New Zealand
2006
M06008; Online publication date 15 August 2006. Received 17 February 2006;
accepted 29 June 2006
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