Record number of seals entangled in litter and fishing nets: ‘It’s a very slow, painful death’

“We recently even found a seal on Schiermonnikoog whose entire body was stuck in a potato net made of orange dental floss,” says Emmy Venema, stranding coordinator at the Pieterburen seal sanctuary. “Luckily he was still alive and was easily rescued.”

This is not always the case. It can be fatal, especially for young seals, which become entangled more often than average. Venema: ‘The seals grow, but the net in which they end up does not grow, which ultimately causes fatal trauma to the airways and blood vessels. It’s a very slow, painful death.’

More seals

Paradoxically, the reason that more entanglements are occurring is actually positive: the seal population in the Netherlands is doing well. This logically increases the risk of entanglement. The gray seal population in particular, which originally comes from Great Britain and more or less coincidentally also settled in the Netherlands, is growing rapidly. According to the latest counts from Wageningen University, their number in the entire Wadden Sea increased by 12 percent per year over the past five years, to 10,544 animals. They share the sandbanks with another 22,621 ‘common seals’, as our local species is called.

The seal has no natural enemy in the Netherlands, apart from humans, which is why their numbers grew steadily after the cessation of hunting in the 1960s. But nowadays the population is confronted with other problems. ‘Shipping and wind farms have also increased exponentially in recent years,’ says Sophie Brasseur, seal researcher at Wageningen University. ‘As a result, the seal population has to skimp on space.’ The common seal in particular seems to suffer from this. Brasseur notes that an above-average number of puppies are born in the Wadden Sea, but that the total population has nevertheless declined in recent years.

It is not known what role entanglement plays in the survival of the young. The cause of death of seals is not recorded in the Netherlands and many entanglements probably occur out of sight, under water. But according to Brasseur, something is definitely going on. “Beheaded or mutilated seals regularly wash up on Dutch and Belgian beaches,” she says.

To help the entangled seals, the three seal centers (Pieterburgen, Ecomare and A Seal) have a plan for a joint Seal Response Team, consisting of veterinarians and specially trained animal caretakers. The idea is that they take a boat out to the sandbanks to free the entangled animals there and administer medication if necessary.

Expensive equipment

Although the plan has been in existence for two years, it has not yet gotten off the ground due to a lack of financial resources. The equipment required, such as a portable anesthesia machine and a hydrophone that can pick up underwater signals, together costs tens of thousands of euros. The seal centers have started a crowdfunding campaign to raise the amount. Until then, they try to borrow the devices from related organizations. “Our wish is that we can set sail for the first time after the summer,” says Venema.

Sophie Brasseur thinks it is a good thing that seal centers report entangled animals, but is at the same time critical of the plan. “If there are dozens of seals on a sandbank and one is entangled, the entire group has to be disrupted to save that one seal,” she says. ‘The seals lose energy as a result and have fewer reserves to have a pup or to survive at all.’

The seal researcher advocates first carefully mapping out where most entanglements occur. ‘Then you can tackle the problem at the source, for example by seeing whether stretched fishing nets can be adjusted in such a way that seals are less likely to become entangled.’