Best Practice Environmental Management for Eucumbene Trout Farm
We have a plan for continual improvement in farm management to minimize impact on the waterways and the broader environment, the opportunity to manage costs though food and waste management. This is important as Trout farms including Eucumbene Trout Farm, Eucumbene, are located in relatively pristine environments here at some 1100 metres above sea level and can impact all down stream users.
It is also important to run the operation on a sustainable basis.
The industry best practice is.
Minising the waste stream by maximizing production efficiency per unit produced.
Key features of our plan are set out below.
The trout farms in Australia are significantly in Victoria with 85% of production. In the Eucumbene region there are Gaden Trout hatchery government owned for dam and stream replenishment, Snowy mountains trout farm in Tumut a commercial operation with table size fish, from whom we intend to source initial breeding stock and Triton Trout focused on fingerlings and caviar.
Eucumbene has and will continue to be focused on tourism with ancillary compatible operations so it has its own unique market position.
NSW Industry and Investment Aquaculture Production report 2009/10 states:
&lsdquo;Freshwater fish, rainbow trout has 26 farms with permits, with commercial production areas of 1.3 hectares producing 148.8 kg"s at an average price of $10.77 a kg to annual production value of $1.6 million in a $53 million market&rsdquo;.
So again Eucumbene occupies a special space and with Jindabyne as Australia’s largest inland tourist destination historically at least an iconic business.
Based on current ponding and tourist operation capacity of the farm would be around 3 tonne per annum certainly at the low production levels as a commercial farm.
We see this plan as an opportunity to be environment friendly while reducing costs.
Critical to Eucumbene is the operation on the Stony Creek as such the creek is totally the source of water and is continually recycled within a closed system with source dam, Stony Lake, effluent pond and biofiltration sand pond / sand filter feeding back to the main dam/Stoney Lake. The tanks are all gravity feed.
The gravity feed also allows oxygen levels to be optimized which can be enhanced by spraying.
There are steps in place with in the system to allow a 100 year event with pipes in the dam wall to allow any natural increase in water to flow out and not impede flood water as required by the water licence and at the worst mesh fencing to allow water to overflow while retaining any fish in the dam preventing any damage to downstream flora and fauna. Of course retaining fish within the farm is good economics.
Chemicals used are minimal with cleaning liquids, Salt and formalin other than what is in the feed. Thus the prospective impact will be low at Eucumbene.
Where ever possible we will reuse any waste on the farm as fertilsiser.
Generally looking at visual impact, flora and fauna, noise and odours are not material or adverse at Eucumbene.
Finally the use of feed premised on 1% of body weight per day and premised on FCR of 1 for 1 with nominal phosphorus means we save wasting food, animal waste to deal with again within the scale of operations proposed even phosphorus are minimal.
Concern has been raised over phosphorus which is important to trout digestion yet levels anticipated is 1.1% of Ridleys trout feed.
Overall keeping these matters in mind will reduce costs contribute to efficiency and operate on a sustainable basis with minimal environmental impact.
Hatchery and Trout
Trout begin their life by the stripping and fertilization of the eggs on the farm from reared breed stock during winter, at Eucumbene initial breeding stock will be sourced from Snowy Mountains Trout farm at Tumut.
The fertilised eggs are in incubators and then troughs or trays in a hatchery where they are held in well oxygenated water. Once hatched and yolk sac absorbed the juveniles are weaned on artifical diets and held in troughs/ tanks until 5g's and can be placed in ponds under roof.
The ponds allow growing fish to be separated by size and reduce risk of canabalisation and can ultimately be moved to grow out tanks or Stony Lake, given the main business is tourism.
Stocking densities of 10-40kg/m3 are common with prospective biomass of 50 % possible, at Eucumbene the operations are well below these levels.
Demand for oxygenated water increases with increasing temperature and proportional to fish size such that .35m/l a day is required for one tonne of fish per year. Or generally 3 times daily water inflow which means capacity of approximately 3 tonne at Eucumbene.
We can increase oxygen with spraying and sprinklers into ponds too.
Feed is a significant cost as is excess waste from feeding so food source is important and Eucumbene use Ridley Trout feed which achieves a average FCR, food conversion ratio, of 1:1 ratio dry weight to weight gain, a significant improvement over the historical past 2:1 ratios.
This feed is also critical in minimizing Phosphorus which while critical to trout metabolism can be a significant pollutant. Again size of operation and prospective growth is not considered at risk at Eucumbene with amounts of phosphorus at 1% of feed.
Fish and here Trout benefit from being cold blooded and floating benefits of a watery environment have significant energy savings over other stock and this results in an efficient FCR for trout. With modern feeds such as Ridleys the optimum feed ratio in terms of costs of feed and growth conversion can be achieved.
In all oxygen and feed needs vary with temperature and thus while average feed is around 1% of body weight daily it can vary between 0.8 and 1.6% without comprising the FCR. Simply put trout will not grow if they are force feed and in fact you will increase waste issues.