Small fry big business
Moving giant fish tanks is a tricky business, writes James Stanford
CARTING live cattle and sheep is one thing, but shifting live fish is a much more complicated matter.
Just ask Nick Petrascu at Dillons Transport in Tasmania, whose company runs three trucks that move live Atlantic salmon for premium fish producer Tassal.
The fish are carried in what amounts to giant fish tanks that run technology a bit more advanced than your goldfish bowl.
The salmon are bred at hatcheries around the state, including a new $20 million plant in the Huon Valley that can produce 400 million baby salmon a year.
When they have grown to about 140g the fish are ready to leave the nursery and are moved to the ocean. To stop them swimming away, the fish are held in pens.
Here, they grow to full size before being harvested.
The crew at Dillons move the young fish from the hatcheries to the sea pens.
Dillons does it with a custom trailer with six fibreglass tanks, each filled with 3000 litres of water.
The company and salmon producer Tassal have just invested in a state-of-the-art set-up based on a Fleetsaver Skel, normally used to cart shipping containers. The Australian-made Freighter product appealed to Nick because of its quality paint and galvanised components. He fitted it with about $30,000 worth of stainless steel.
So why does Nick worry so much about using corrosion-resistant materials? The salmon are carted in salt water and some of it overflows, so Dillons has to sandblast his other two flat-top trailers and repaint them after every season.
The Skel trailer is equipped with a wireless automatic system which senses the oxygen level of each tank and adjusts it accordingly.
The drivers also pull up and check the systems every half-hour and can change the oxygen levels manually if required.
‘‘If the oxygen level gets down too low, they’re buggered,’’ Nick says. ‘‘You have to be on the ball.’’
This level of care is understand- able given the sensitivity of the fish and the fact that each load is worth about $250,000.
They need to be delivered to the sea pens in perfect condition and Tassal is happy for Dillons to take as long as it needs to get the job done properly. Nick says the salmon don’t appear to mind the drive.
‘‘I think they enjoy the motion of the water,’’ he says.
Here’s some trivia: inside the tank they all swim in a right-hand rotation and in the northern hemisphere they swim around to the left. It’s like the way the water swirls in a toilet depending on which hemisphere you are in.
So what’s it like to drive with a trailer full of water and fish?
Unlike most trailers carrying a large amount of liquid there are no baffles to stop the water from shifting around and making the load unstable, but having the different compartments helps.
‘‘If you had one big tank it would be a real nightmare, but it’s not bad when you divide it up into six,’’ Nick says.
‘‘You can just drive normally. They travel well because the tanks are full. If you let the water get down any more than 8-10cm from the top it would change altogether. You would get a lot of surge.’’
A small gap at the top of the tank allows the fish breath (carbon dioxide) to be released.
Dillons pull the trailer with a new Kenworth T402. It has crosslocks to give it grip on gravel and the icy roads Tasmanian truckers can come across.
‘‘The way we drive trucks over here is completely different to the mainland. If you are not going uphill you are going downhill and if you are not doing that you are going round a corner. You wouldn’t have a truck with anything less than an 18-speed (gearbox) and cross-locks,’’ he says.
‘‘Sometimes you need all four drive wheels locked and driving.’’
Live cargo: this hi-tech Dillons truck hauls baby salmon in six fibreglass tanks, each filled with 3000 litres of water.
Climate control: sensors monitor and regulate the tanks’ oxygen levels and temperatures.