Many states transport fish from out-state-hatcheries to local hatcheries and from local hatcheries to lakes and reservoirs. Maintaining proper temperature and dissolved oxygen levels in the transport tanks is critical to the health and survival of the transported fish. A failed aeration or temperature control system can result in thousands of dollars of lost fish.

In the past, drivers have had to periodically get out of the truck, climb up to the tanks on the truck or trailer bed and manually measure the temperature and dissolved oxygen in each tank with a handheld meter. This practice of stopping and getting in/out of the truck was a safety issue for drivers and increased the duration of the trip.

In 2021, Frontier Precision assisted a State fish and wildlife agency with two systems to measure temperature and dissolved oxygen levels in fish transport trucks. A transport truck with a four- and eight-tank system was equipped with an automated temperature and dissolved monitoring system that provides real-time data to the driver in the truck cab.

Each tank includes one In-Situ RDO Blue temperature and dissolved oxygen sensor that is continuously measuring and transmitting data to an In-Situ TrollNet Hub. The Hub combines the data from multiple temperature and dissolved oxygen sensors and makes it available to a small, 900 Mhz radio. The Hub also acts as both a junction box and a weatherproof enclosure for the radio. Both the radio and the Hub are powered by the trucks 12VDC system. The radio in the Hub enclosure sends the water quality data to a companion radio in the cab of the truck. The radio in the cab is connected via USB to a MS Windows tablet. A custom app on the tablet displays real-time readings of temperature and dissolved oxygen for each tank. The tanks are numbered to match an address on the sensor so the driver knows exactly which tank is having problems.

“The system is excellent! One thing I learned from it is when ya load a tank the DO immediately drops 50%. So if you are at 100% saturation, the Do will drop to 50% which is around 5 mg/l and is almost in the danger zone for trout. So, as soon as my stones are covered with water, I turn on the O2 and get it to over 200% saturation so the fish aren’t starting with a O2 deficit. This has really helped hauling the fish with less stress. I’ve had 2 occasions specifically where the O2 has dropped and I found 1 burst cap had blown on a flow meter and was able to stop and repair it. The other I found a leak on the line I was able to stop and repair it. Since having the system, I haven’t lost any fish. There has also been several times I’ve noticed one tank had lower oxygen levels so I moved some fish out of that tank and redistributed them to get the O2 at a better rate. I’m impressed with the system. I figured a 4 tanker load of fish from the hatchery is worth $15,000-$20,000, depending on the size and amount of the fish. I also know the fish we haul from Arkansas are worth between $20,000-$40,000. So big time saving system.”  — Barry Nielson, Utah Division of Wildlife Resources, Springville, UT Hatchery

Frontier Precision is a manufacturer’s representative and systems integrator. We can provide sensors and measurement systems for your projects as well as complete system integration. To get instrumentation for your projects please contact Steve Combe or Martin Soto.



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