The upland bully is a prolific and widespread member of New Zealand fr
eshwater fish communities that may mature at age 1 (or earlier). It be
gins spawning in spring, laying as many as eight clutches of eggs over
the spring and summer, at periods as brief as 13 days. Ovaries contai
n two modes of maturing oocytes, so that oogenesis must be continual d
uring the spawning season. This poses difficulties in fecundity estima
tion, which were solved by captive rearing. The ovoid eggs are about 2
mm long; egg size declines with clutch number during the summer, but
increases with fish size. Clutch size varied, in 70 spawnings, From 12
1 to 880 eggs, with total seasonal fecundity up to >5000 eggs. The pro
duction of multiple clutches greatly increases seasonal fecundity and
may explain the success of this species in sometimes unreliable or har
sh environments. (C) 1997 The Fisheries Society of the British Isles.