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 μ m. Batch fecundity was accordingly estimated at 74500 ± 34900 eggs/kg body weight. On the basis of cyclic changes in gonadosomatic index and levels of the sex steroids estradiol‐17β and 17α,20β‐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 298000 (± 139600) and 447000 (± 209400) eggs/ kg body weight. Notwithstanding inter‐annual and inter‐locational variation, these fecundity estimates provide a guideline for the management of banded wrasse.