New Zealand Journal of Marine and Freshwater Research abstracts
Fecundity of banded wrasse (Notolabrus fucicola) from Otago, Southern
New Zealand
Nicholas J. Harwood*
Department of Marine Science
University of Otago
P.O. Box 56
Dunedin, New Zealand
email: nharwoodnz@yahoo.co.nz
P. Mark Lokman
Department of Zoology
University of Otago
P.O. Box 56
Dunedin, New Zealand
*Present address: Leigh Marine Laboratory, University of Auckland, P.O. Box
349, Warkworth 1241, New Zealand.
Abstract To better understand the reproductive biology
and to supply crucial data for fisheries management, fecundity of banded wrasse
(Notolabrus fucicola) from Otago, southern New Zealand, was investigated
over a 12-month period from January 2004 to January 2005. The spawning season
for banded wrasse from Otago was deduced to be from September through to December.
The threshold diameter of oocytes undergoing germinal vesicle breakdown in
vitro, therefore constituting a batch, was found to be c. 500 µm.
Batch fecundity was accordingly estimated at 74 500 ± 34 900 eggs/kg body
weight. On the basis of cyclic changes in gonadosomatic index and levels of the
sex steroids estradiol-17b and 17a,20b-dihydroxy-4-pregnen-3-one, it is likely
that wrasse spawn once each lunar cycle during the spawning season, resulting
in four batches of eggs each year around the time of the full moon. Calculated
annual fecundity ranged between 298 000 (± 139 600) and 447 000 (± 209
400) eggs/kg body weight. Notwithstanding inter-annual and inter-locational variation,
these fecundity estimates provide a guideline for the management of banded wrasse.
Keywords banded wrasse; spawning cycle; moon phase; Notolabrus
fucicola; reproduction; fecundity; Otago
New Zealand Journal of Marine and Freshwater Research, 2006, Vol. 40:
467–476
0028–8330/06/4003–0467 © The Royal Society
of New Zealand 2006
M05046; Online publication date 1 August 2006. Received 19 July
2005; accepted 21 April 2006
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