FISH stocking MAFSA style involves many hours of preparation and looking after fingerlings, as well as equipment maintenance. But there is a fun side to it: fishing for broodstock sooties!
Not just any old sooties will do for broodstock. We had to get several males running milt and also a couple of females carrying advanced roe so that they’d be receptive to hormone-induced breeding in the hatchery. In the wild, a female sooty grunter doesn’t release all her eggs at once. In the hatchery, hormones induce the females to drop their eggs at once to allow them to be fertilised by the males.
When spawning, sooties prefer shallow, highly-oxygenated running water. Impoundments sooties do roe up but getting them at the right stage of roe development is tricky, so we concentrate our efforts in rapids. The rapids can be man-made, like the inlet channel at Kinchant Dam, or natural ones such as those in the Pioneer River system. Sooties are turned on by a rise in water levels, high temperatures and humidity, and water releases from the dams provide perfect conditions.
Because we’re collecting fish for stocking, MAFSA members have access to parts of the Pioneer River system that are off limits to the public. Property owners have been contacting us to enable us to cross their property to good spots, and sometimes helping us to collect stock, which is appreciated. We never collect broodstock from the same place twice.
On our recent trip we fished water near the Mirani Weir, Kinchant Dam and near the Marian Weir. Another successful spot for us has been near Marian’s rapids and further up the valley near Finch Hatton. This time our best results were from near Mirani weir, a spot that many of our newer members had never fished before.
My first cast with a 40mm gold Fat Rap to the head of a pool just above a small set of rapids got smashed quick time, and after a short tussle I brought a healthy 350mm sooty to the bank. After I’d given him a squeeze to confirm that he was running milt, I popped him into a 20-litre bucket to be lugged up the bank to our transport tank – a 200-litre trailer-mounted tank fed with bottled oxygen. I transferred him quickly so that he wasn’t stressed more than necessary.
We caught plenty of fish in that session, and gently squeezed each one along the flanks to see whether it was running milt. We also looked to see whether the vents were distended and coloured – signs of a female in roe. Many sooties are obviously females in roe because of the size of their gut and appearance of the vent. Dam sooties sometimes look to be in roe when they’ve just had a big feed, but you can tell for sure from the appearance of the vent.
We ended up transferring seven fish during that session, although we caught many more, and we headed off to Kinchant Dam. Here we drew a blank except for Bob Sutherland proving again what a ‘tinny’ angler he is. There was a small opening among some lilies and Bob lobbed his lure in there to be greeted by a barramundi having a slash at his lure. Fortunately there was no hookup on the light gear, but it still shook him up a bit.
After Kinchant we tried near Marian, but by this time the activity had slowed right down. At 11am we called it a day and took the fish back to the hatchery. The females in roe were anaesthetised and injected with hormone.
The next day we discovered eggs in the hatchery but unfortunately they turned out to be not viable. This could have been because the females were past the optimum period of roe development or perhaps because the males didn’t fully fertilise the eggs. Not to worry – we just have to plan another fishing expedition! Why not join us sometime and make a contribution to the health of Mackay district fisheries?
1) The fun part of a stocking program is collecting the broodstock.Reads: 1006