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 impulsive 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) impulsive startle devices are approved. If your deterrent system meets the criteria then you’re immediately issued a certificate of approval valid for one year.
The web tool asks for information on three key parameters: frequency range; maximum underwater volume; and Duty Cycle (a measure of how often the device produces sound).

For example, with Ace Aquatec’s RT1 deterrent (a low frequency impulsive startle device) you would select multi-frequency on the Web Tool, choose the following parameters, then save your certificate:

• Frequency Range: 1-2kHz
• Maximum Volume: 195dB
• Duty Cycle: between 0.8% and 7% (depending on your typical usage)

While this guidance helps clarify how the MMPA will be applied, it’s also important to understand if other local regulations apply to your site. For example, if you need a European Protected Species (EPS) Licence for your site then any MMPA guidance is in addition to that, not instead of it.

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

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