Nicolle van Heerden ASU50

  • Tauira / Student
    Nicolle van Heerden
  • Kaiako / Lecturers
    Anke Nienhuis, Phoebe Lee

The ASU50 Sterilisation Unit was designed to address the threat of stoats that harm and prey on native biodiversity. Traps and bait stations that are currently being used by conservationists are effective in killing and eliminating invasive species, but unfortunately, stoats are notorious breeders making it hard to keep up with the breeding rates of these predators.
Stoats can live between four-six years and can give birth yearly to 7-12 kits. For every 1 female stoat that has been killed in these traps, at least five would’ve replaced it annually. Male stoats killed could’ve impregnated multiple females before their death. If these stoats were sterilized before their death, they wouldn’t have been able to reproduce more in their place.
The ASU50 lures the stoat into the unit using premade chocolate bait or blood. Whilst, the stoat is sniffing and cautiously entering the unit, its neck and back are being scanned for a coloured ink mark. An ink mark indicates to the unit that the stoat has already been sterilised so, the unit won't turn on. If no ink mark is detected, the sterilisation unit will turn on and set the dosage amount. Two smaller circles within the unit help to slow the rate at which the stoat is entering and exiting, and act as grip pads preventing the stoat from thrashing whilst being injected. When the stoat reaches the bait it’ll brush up against the pressure trigger, letting the unit know that the stoat is in the prime position to be injected. The injection pen will move down into the unit and inject the stoat with the sterilisation solution. It’ll retract and the stoat is free to leave. As the stoat is backing up, it will back up into the ink-soaked sponge by the exit marking it as sterilised.
Chemspray is a sterilisation solution that is currently in development for the sterilisation of stray cats and dogs, which is currently being tested on rodents. Results show that it can currently sterilise female rodents for up to 2 years without any adverse effects on the animal or the environment. This unit is meant to be used before or during stoats' mating season, to keep costs down. This unit should be used alongside existing traps and bait stations to successfully decrease the population.