NOAA’s Arc

Ace Aquatec RT1 on pen photo

Are your predator deterrents MMPA compliant?

by Nathan Pyne-Carter CEO of Ace Aquatec

There are many unanswered questions about what it means to be compliant with the Marine Mammal Protection Act (MMPA). Thankfully there’s now more clarity when it comes to one particular area; protecting your fish from predator attacks.

America’s National Marine Fisheries Service – informally known as NOAA Fisheries – issued new guidance in August detailing what kind of predator deterrents are compliant with the MMPA.

What is the MMPA?
When new import provisions of the MMPA come into play on 1 January 2022 the USA will ban fish product imports from countries whose farming operations cause ‘mortality and serious injury of marine mammals’. NOAA Fisheries defines ‘serious injury’ as ‘an injury that is more likely than not to lead to the death of the affected marine mammal’.

Some countries which previously sanctioned seal shootings as a last resort to protect fish from attacks – such as Norway and Scotland – have already taken steps to move away from these practices and adjusted their predator management practices in response to the MMPA.

Non-lethal methods of deterring predator attacks have also been reviewed but it’s important to understand the MMPA is not a ban on acoustic devices or any particular technology; the focus is on reducing mortalities and serious injury.


New guidance from NOAA
New guidance from NOAA is open for public comment until 30th October 2020 but gives a good indication of how the MMPA is likely to be interpreted.

Certain non-acoustic deterrent methods are very clearly prohibited. These include chemical irritants, sharp objects, chasing with vessels, and explosives like firecrackers.

When it comes to acoustic deterrents though there’s a split between methods below 170dB in volume (eg. ineffective low energy options such as whistles, ‘vuvuzelas’ and air horns) and those using sounds above 170dB (eg. underwater acoustic transducers).

The ineffectual low energy devices are accepted as a category, and the higher volume startle devices are approved for use if they meet specific criteria.

There’s a quick way to check if your deterrents are compliant

NOAA has launched an Acoustic Deterrent Web Tool to help quickly check which higher volume (over 170dB) startle devices are approved.

Try out their tool to see if your current deterrent system meets the criteria. If it does, you’re immediately issued a certificate of approval valid for one year.

If you already use Ace Aquatec’s RT1 deterrent (a low frequency device) you would select multi-frequency on the Web Tool, and enter in the requested parameters for the Ace Aquatec deterrents you have on your sites using the table below for reference. For the low frequency RT1 deterrents please generate a certificate for each setting.

Ace Aquatec Deterrent RT1 Flex RT1 Ring US3
Lowest Frequency Pitch (kHz) 0.8kHz 1kHz 8kHz
Highest Frequency Pitch (kHz) 1.2kHz 2kHz 11kHz
Average source level (dB)* 176dB 180dB 181dB
Duty Cycle 11% 11% 10%

Then, enter your name, the name of the deterrent (Names in table above), the species you are trying to deter? (harbour seal, grey seal), and select “Generate Certificate”

For guidance on how to process any of our other deterrents through the Web Tool please get in touch and our team will walk you through it.

*  Average within a transmission: re 1uPa rms @ 1m”

Ace Aquatec have written a self-certification guide for their customers that will be updated as NOAA finalises their guidance. The latest version will always be available at




Featured: Ace Aquatec RT1 low frequency deterrent on a fish farm pen
Above: Certificate of Approval from NMFA/NOAA Web Tool


Keep up with us

Posted in ,
Fish Farmer cover July 2024

The July 2024 issue of Fish Farmer is out now