Salmon farmers can no longer shoot problem seals as a last resort and the use of acoustic deterrent devices (ADDs) has been discontinued following advice from Scottish government agency Marine Scotland that they might cause harm or disturbance to cetaceans (whales, porpoises and dolphins), which are designated as European Protected Species (EPS) in law. ADDs might therefore require an EPS licence to permit their use.
The removal of these seal control options mean farmers must now rely only on anti-predator nets to protect their stock, but these do not stop seals stressing the fish by pushing at the nets, or from sometimes climbing on to pen walkways and into the pens.
Good intentions but a bad situation
Seals are a protected species and cannot be shot by the public in Scotland, but both salmon farmers and wild fisheries managers were able to apply for licences to shoot seals that were persistently predating fish and couldn’t be dealt with using a non-lethal method.
That option was taken away from salmon farmers at the end of January because the Scottish Government feared the salmon industry’s £180 million-a-year exports to the United States could be blocked under a provision of the US Marine Mammals Protection Act (MMPA) that comes into force in 2022.
That provision prohibits the import of fish if a marine mammal has been harmed or killed as part of their production.
The use of some ADDs might also constitute harm under the MMPA, but US authorities have yet to give a definitive answer about that.
Fish farmers in Norway do not face the same issues with the MMPA as those in Scotland because seals, and otters, can be killed by licensed hunters who are not connected to the salmon industry. Seals are hunted professionally in the Arctic, but also by people hunting for pleasure in the coastal regions. According to Norwegian animal rights group NOAH, which wants to end seal slaughter, around 6,000 seals were killed in 2019, mostly in the Arctic.
Salmon Scotland has pointed out that the current lack of options that farmers have for dealing with seal attacks makes it difficult for them to meet their obligations under the Animal Welfare Act 2006, that anyone responsible for an animal must take reasonable steps to make sure the animal’s welfare needs are met.
Harmless to cetaceans
Salmon Scotland (formerly the Scottish Salmon Producers’ Organisation) does not want permission to shoot seals reintroduced but wants Marine Scotland to clarify the position on what ADDs its members can use, if any.
Ace Aquatec has developed a range of next-generation acoustic and electric shock seal scarers that do not harm the seals or cetaceans, but these have not yet been given the green light by Marine Scotland.
Pyne-Carter said: “Statistics recently published by Salmon Scotland have starkly highlighted the cost salmon farmers are paying in lost fish and revenue due to seal predation. We support the call to action for further government talks as it is critical that farmers are able to protect their livestock and livelihood from this escalating issue.
“Our recent advances in startle response technology help enable farms to take a blended approach to predator control. The most successful safeguards against predation are a multi-faceted approach that incorporates new generation acoustic and electric startle response systems, reinforced anti-predator netting, and good farming practices. This combination can ensure that predators are responsibly encouraged to predate on wild, not farmed, fish.
“Marine Scotland have created a process which is not transparent and makes no exception for technologies which fall outside the scope of the EPS process.”
The latest versions of Ace Aquatec’s Acoustic Startle Response (ASR) and Electric Startle Response (ESR) equipment are triggered when a system of cameras, night vision and thermal imaging identifies an approaching predator. The Artificial Intelligence-linked cameras are trained to recognise the shape of seals’ heads bobbing at the surface of the water and can distinguish seals from porpoises and whales.
The ASR has signal characteristics that focus on sound quality rather than volume, enabling Ace Aquatec to tailor the frequency of the device to the hearing sensitivity of a target species. The sounds are programmable, randomised pulses with 3- to 10-millisecond rise times. Ace Aquatec says the short amount of time from the onset of the sound to its highest peak creates a visceral response in mammals that cannot be overcome.
Successive encounters with this noise create sensitisation (gets worse) rather than habituation (gets used to it) which means that sound is more impactful at lower volumes on successive encounters. The company adds that the system keeps being effective because it randomises the frequency of the pulses, the volume of pulses and the duration of silences.
There are three ESR devices: an electric fence to deter seals from climbing into a pen, and an electric net and “electric fish” – a fake mort with protruding electrodes – to give below-surface protection. The ESR devices give a seal a harmless but unwelcome shock.