224 
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ground in the northeast Indian 
Ocean; and Japanese longine 
vessels operating in the South- 
ern Ocean (on feeding grounds 
off Tasmania, New Zealand, and 
South Africa and on staging 
grounds in the southeast Indian 
Ocean) (Fig 1). 
The ovaries of 475 females 
were collected from the com- 
plete size range of southern 
bluefin tuna caught on the 
spawning ground. Ovaries were 
removed at sea, labelled, stored 
on ice, and matched with the 
corresponding tuna carcass at 
Benoa in the Sunda Islands. 
Dressed weight (where fish was 
gilled, gutted, its fins removed, 
and its tail stock left intact) was 
measured to the nearest kg, and 
fork lengths of most fish to the 
nearest cm. A subsample was 
removed from 200 ovaries and 
fixed in 10% buffered formalin. 
The ovaries were frozen and 
flown by airfreight, along with the 
subsample, to Australia. In addi- 
tion, up to 30% of all longline 
catches landed at Benoa were 
monitored and the individual 
weights and lengths of southern 
bluefin tuna were recorded. 
Ovaries from the Southern 
Ocean were collected at sea from 
the fishing grounds around Tas- 
mania, New Zealand, South Af- 
rica, and the southeast Indian 
Ocean. The areas around Tas- 
mania, New Zealand, and South 
Africa are considered to be feed- 
ing grounds for immature and 
adult southern bluefin tuna, 
whereas the southeast Indian 
Ocean is the area where pre- and 
postspawning fish are caught 
during the spawning season. In 
total, ovaries were collected from 
2,340 females from the feeding 
grounds in the Southern Ocean 
and from 393 females from the 
southeast Indian Ocean. Ovaries 
were frozen immediately after 
collection. Fork lengths were 
measured to the nearest cm. 
