9 minute read
Why tackling the seal problem is so difficult
No seal of approval
Scottish technology is deterring predators around the world – but not in Scotland
Preda� on by seals is es� mated to cost Scotland’s salmon producers around £12m each year. Even if seals can be kept out of a pen, their presence nearby can cause fi sh to suff er from preda� on stress, which can exacerbate other health risks.
Seals and other marine mammals are protected species, however, which rules out using lethal means to protect farmed fi sh. Un� l recently, fi sh farmers made extensive use of non-lethal protec� on measures, including acous� c deterrent devices (ADDs).
ADDs don’t just impact seals, however. The “wall of sound” emi� ed by the older genera� on of ADDs is also very problema� c for cetaceans, that is whales, dolphins and porpoises, which are highly protected species.
Legisla� on passed in the US – the Marine Mammals Protec� on Act (MMPA) – makes it an off ence to harm or disturb protected species, and because it eff ec� vely bans seafood imports from jurisdic� ons that have not passed equivalent legisla� on, it eff ec� vely applies to anywhere that wishes to sell its seafood to the US.
Cetaceans are European Protected Species (EPS) and in Scotland, ac� vi� es in the marine environment that have the poten� al to kill, injure or disturb them are subject to a strict licensing regime.
Unless an EPS licence is in place, it is an off ence “deliberately or recklessly disturb any dolphin, porpoise or whale”.
In March last year, the Sco� sh Salmon Producers Organisa� on (SSPO), since rebranded as Salmon Scotland, announced: “All devices the sector does not have total confi dence in, with regards to the harming of protected species, have been turned off and removed from the marine environment.”
Since then, however, the sector has moved on s� ll further. Salmon Scotland told Fish Farmer: “No ADDs are currently in use for commercial purposes on Sco� sh salmon farms and as such there have been no licences applied for.”
This is also confi rmed by Marine Scotland, which runs the licensing regime and says that to date no EPS licences have been issued to fi sh farms.
Marine Scotland says: “It is for fi sh farm operators to determine whether use of an ADD at their site will require a licence to disturb EPS.”
It adds: “Given current scien� fi c advice, it is likely that an EPS licence will be required for all currently available ADDs unless it can be demonstrated that a device will not cause disturbance to cetaceans.
“EPS licences may be granted in certain circumstances following an applica� on and determina� on
Above: Seal Left: Ace Aquatec RT-1 device Opposite: Genuswave TAST device
process. Applicants must demonstrate that three licensing tests are sa� sfi ed: (1) there is a licensable purpose; (2) there are no sa� sfactory alterna� ves; and (3) the ac� ons authorised will not be detrimental to the maintenance of the popula� on of the species concerned at favourable conserva� on status in their natural range.”
Sco� sh Ministers have to date granted four EPS licences that allow ADD use in rela� on to non-aquaculture ac� vi� es such as piling and unexploded ordinance clearance at sites in the Moray Firth and on the east coast of Scotland.
Fish farmers in Scotland with sites aff ected by seals are, therefore, dependent on an� -predator nets such as FISA’s SUPRA an� -predator solu� on, a custom braided kno� ed net produced with third genera� on high density polyethylene (HDPE). FISA works with Boris Net and Gael Force to distribute this in the UK.
Could the latest genera� on of ADDs be less harmful to cetaceans, however? Rather than relying on a constant or near-constant “wall of sound”, the latest models use “startle” technology in which a pulse is randomly emi� ed or triggered by sensors which can detect the near approach of seals. The pulse is enough to startle seals but, the manufacturers say, will not cause problems for whales and dolphins in the area.
The “startle” approach is also intended to avoid the “dinner bell” problem, when a constant acous� c signal, while unpleasant for the seals, also acts to indicate the presence of food.
With Ace Aquatec’s ASR (Acous� c Startle Response) devices, for example, just 10 milliseconds from the onset of the sound to its highest peak creates a visceral response in mammals that cannot be overcome, the company says.
The new genera� on deterrents can also be fi ne-tuned so that the acous� c pulse operates in a frequency range that does not impact most cetaceans.
Ace Aquatec also off ers an electrifi ed dummy fi sh which creates a physical startle response that scares the seal without harming it.
GenusWave has developed a seal deterrence system that uses Targeted Acous� c Startle Technology (TAST). The only acous� c deterrent approved by the Aquaculture Stewardship Council, TAST was developed a� er more than a decade of research by world-class marine biologists at the University of St Andrews’ Sea Mammal Research Unit. It is ironic, says the company’s Managing Partner Steven Alevy, that a technology funded and developed in Scotland is not being used in Scotland. Instead, TAST is used on salmon farms in Norway.
In Scotland there con� nues to be an apparent presump� on against ADDs and new acous� c technologies alike. Alevy says: “Even a technology that does not disturb EPS requires an EPS licence to disturb. Farmers are in a bind. They do not want to disturb EPS and certainly don’t want to be known as having a licence to disturb EPS, which the public may view as de facto proof that the farmer must be disturbing dolphins.
“Sco� sh salmon farmers have turned off their conven� onal ADDs at a great personal sacrifi ce because they are suff ering losses from seal preda� on. What has gone unreported is the impact on the salmon: fi sh health and welfare has been compromised as a result of the increased preda� on stress. Salmon have an acute sense of smell and can detect a seal swimming in proximity to a farm. Stress causes the salmon to produce cor� sol and not mucus, which is the fi rst line of defence against parasites and pathogens. Next year’s harvest is likely to experience a severe increase in biological illness because salmon farmers do not have tools that keep seals away from their salmon.”
Marine Scotland’s “frequently asked ques� ons” document on ADD licences spells out: “If… by virtue of the sound levels and frequencies at which they operate, it can be shown that ADDs (or related systems) cannot disturb cetaceans, then an EPS licence is not required. However, robust evidence to validate this claim must be provided to MS-LOT. In prac� ce, the hearing ranges of seals and cetaceans overlap, so there may be limited scope for iden� fi ca� on of deterrents to which only seals are sensi� ve.”
Steven Alevy notes that the US MMPA, and the EU, accept peer-reviewed and published research as evidence of non-disturbance. Perhaps, he suggests, Scotland can also consider accep� ng peer-reviewed research.
Alevy is op� mis� c that Mairi Gougeon, Cabinet Secretary for Rural Aff airs in the Sco� sh Government, will fi nd a way forward: “She is a though� ul leader with a vision for the future and she is keen to encourage new technology that benefi ts Scotland and its industry. I believe that new regulatory changes will be sensi� ve to the extreme compe� � ve threats facing Sco� sh exports as well as guide and support the salmon farming industry over the long term.”
For now however, Dr Iain Berrill, Head of Technical at Salmon Scotland, says: “Salmon farmers have a statutory duty to protect the animals in their care, but as � me goes by we have fewer and fewer op� ons to help manage against seal a� acks. Salmon farms and seals can co-exist quite happily in the marine environment, yet seals can infl ict vicious and widespread damage, killing signifi cant numbers of fi sh in each a� ack.
“Predator control is a con� nual challenge for the sector and we require the ongoing development of eff ec� ve tools to ensure we can protect our stock.
“Salmon farmers use a range of measures to exclude predators, and this is very site specifi c, but no ADDs are currently in use on Sco� sh salmon farms.” FF
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