Fish stripping in Tasmania

by Carl Hyland on 23 Apr 2012 Stripping fish, public displays. Sounds like something lewd, but nothing can be further from the truth.

Each year, the Tasmanian Inland Fisheries Service conduct their annual, ‘trout displays’ in the Central Highlands to coincide with the annual spawning runs of trout and this year is no exception.

Come and see hundreds of wild brown trout on their annual spawning run from Great Lake in the Liawenee Canal. Watch wild trout being stripped of eggs for culture. Catch a trout for dinner from the kid’s fish-out pond. Visit trade exhibits, with boats and fishing gear. Enjoy refreshments, competitions and give-aways. View displays about fisheries management. Learn what’s happening around the fishery. See live freshwater fish aquaria. Ask questions of Inland Fisheries staff. Talk to trout fishing and fly-tying experts. Take a helicopter ride above the Lake or a bus ride along the Canal. Buy something special, including a Trout Fish Tasmania souvenir. Make it a day out with the family or a weekend away. The event is held at the Inland Fisheries Service Field Station, Liawenee, Great Lake and runs from 10 am to 3 pm on both days. It takes about one and a half hours to drive to Liawenee from Launceston or Hobart via the Highland Lakes Road. The weather is very changeable in the highlands, and normally cold, so it is important to dress warmly. For more information, call the Inland Fisheries Service on (03) 6261 8050 or 1300 INFISH during business hours, or click here.

A lot of people often ask, why do the I.F.S strip fish when natural spawning takes place anyway?

Good question and hopefully, the table below will answer that and I have included a statement from the I.F.S as to why and where they stock fish or raise brood stock at their state of the art hatchery in Southern Tasmania.

A number of stocking initiatives were trialled through the drought years, some successfully others not. The stocking of brook trout into waters containing other salmonid species has clearly not worked, however the hatchery stocking regime at Penstock Lagoon has been a spectacular success. The Service has deliberately taken an adaptive management approach in these stocking programs aimed at evaluating and fine tuning the number and appropriate mix of species at each water. This program has necessarily focused on a limited number of waters since the majority of Tasmanian fisheries sustain healthy populations of wild naturally recruiting brown trout and less commonly wild rainbow trout populations.

The Inland Fisheries Service, Inland Fisheries Commission and its predecessors have historically stocked a range of fisheries with stock from the Salmon Ponds or other recreational hatcheries. These fish have been on-grown to various sizes from fry to fingerlings or even yearlings largely depending on the prevailing environmental conditions experienced by the hatchery. In later years the only remaining hatchery was the Salmon Ponds hatchery and this increasingly suffered from poor water flows and high water temperatures, making the production of stock very unreliable in size quantity and quality.

In undertaking the stocking programs the Service has out of necessity utilised a range of stocks prior to the development of better hatchery facilities in New Norfolk in 2008. The new hatchery is only now meeting its full production capacity. The Service has continually and clearly stated that its primary aim is to produce and stock waters with wild stock fish sourced from wild run spawners (browns and rainbows) originating from Great Lake. The Service promotes these fish as ‘wild stock fish’ and does not seek to portray them as wholly ‘wild fish’. It does not however, accept that these fish are in any way ‘domestic stock’.

These hatchery fish are on-grown by the Service only to a size sufficient to optimise their chance of survival in the receiving water. They are captive for 8 to 10 months and are stocked at 1g, 5g, 10g or up to 20g (around 150mm in length) when redfin perch are present.

The Service has a policy of using wild stock fish in the Central Highlands and has now met this, except for the Bradys Chain of lakes which received a small number of domestic salmon in 2010. This was a trial stocking and there are no plans to stock this water with salmon in 2011. Similarly with brook trout stocked into Bronte Lagoon in 2009, there is no plan to stock this water with brook trout in 2011.

Popular family waters, away from the high country in lowland regions at Brushy Lagoon, Lake Barrington, Lake Meadowbank and Craigbourne dam, will continue to be stocked with a mixture of domestic and wild stock fish for the near future. They are key waters for receiving large Atlantic salmon

The importance of maintaining the capacity to produce wild stock fish was highlighted by the breaking of the drought since mid 2009. Since then, the Service has grown and stocked brown trout (unavailable from commercial hatcheries) into Tooms Lake, Craigbourne Dam, Lake Crescent and Lake Dulverton, dramatically speeding the recovery of these fisheries. Several river fisheries also received supplementary stockings following the devastation of the drought, namely the middle Macquarie, Coal, Clyde and Break O'Day rivers. Wild adult browns have also been used according to the annual stocking program, however their availability was limited by the vagaries of the runs at Great Lake and Arthurs Lake this year.

The production of triploid browns and rainbows from the New Norfolk hatchery is now being achieved through the modern set up of incubators and tanks, and the recent investment in a custom made trout triploiding vessel. This hyperbaric chamber was imported from France and is the first of its kind in Australia. Although triploiding is common-place in the industry, no-one else is doing this with ‘wild eggs’ harvested from ‘wild fish’, and certainly not using the iconic Tasmanian wild brown trout.

The triploids, which are sterile, tend to grow faster when they reach maturity and having no gonads, they do not spawn and waste energy in reproduction. They provide a new dimension to fisheries particularly those with no capacity for natural recruitment. Far from being a turnoff to the serious angler, the Service has received enthusiastic support from mainstream anglers for fisheries at Four Springs Lake, Curries River Reservoir, WaterHouse Lakes, Brushy Lagoon Lake Crescent and Penstock Lagoon to benefit from these fish.

Stocking has been a point of debate in recent times from some sectors of the angling community. It will continue to be an essential fisheries management tool to address fisheries with poor recruitment. Other fisheries that rely on stocking although minor will continue to need supplementation from hatcheries. These include Big Lagoon, Lakes Skinner, Plimsol, Selina and Rolleston, and Pawlena Dam, as well as the popular program of farm dam stocking, particularly in the northern part of the State.

And this is the end result...