Murray Darling Fisheries in Australia, was experiencing accelerated algae growth and cage fouling in their freshwater grow-out pond located in the Riverina, Australia. Cage fouling caused a severe decrease in water flow and oxygen levels in the cages requiring them to be cleaned every 2-10 days. It was also noted that after each cleaning, fish would stop eating for a full day afterward. Each cleaning being labor intensive and presenting a health threat for fish due to interrupted feeding cycles, Murray Darling sought to minimize the frequency of cage cleaning.
The Experiment
Phase I – Already knowing the schedule of cage cleaning, (once every 2-10 days), a single HBS manufactured , ultrasonic algae control device was placed in a cleaned cage before the cage was placed back in the water. The cage was then monitored to determine how much of an effect the HBS unit had on controlling algae and other biofouling agents and how HBS technology would affect the frequency of cage cleaning. Phase II -Once the cage reached a point where cleaning was necessary, the cage was removed from the water, cleaned and returned to use WITHOUT the HBS system activated. Cage cleaning frequency was then remeasured.
The Results
Phase I -With the cage cleaned and the HBS unit activated, cage cleaning necessity was not reached until a 3 month period had passed.
Phase II -When the cage was reintroduced into the water with the HBS system turned off, it took only 10 days for the unit to reach a point where it needed to be cleaned.
Conclusion
Introducing HBS technology into the Murray Darling fish cages reduced cage cleaning frequency from once every 2-10 days to once every three months. A 97% increase in time between cleanings. Considering each cleaning requires an investment of money and time, this 97% can be applied to both labor and other cleaning expenses as a measure of savings.
HBS technology prevented a downtime in fish feeding leading to an increase in overall fish health and increased fish growth. This facilitated a greater yield of fish crop in an abbreviated amount of time. By reducing cage cleaning frequency and expense while also contributing to greater fish health and yield, HBS technology was easily able to prove it’s value in fish hatcheries where cage fouling is an issue.