Entangled seal with a transmitter

In the summer, we received a report of an entangled grey seal near Rottumeroog. Not only did she swim with a fishing net around her neck, but also one with a transmitter on her back. Thanks to the help of a ship of the organization Waddenunit we were able to catch this seal. She was given the name Irene.

verstrikte zeehond met zender op het strand

Seal Irene

Near Rotummeroog, the crew of the ship De Harder of the Waddenunit (part of the Ministry of Agriculture, Nature Management and Food Quality) reported a seal. It was a young grey seal entangled in a fishing net. The net was tight around the neck.

The crew managed to free the animal. But the wound was very deep and bleeding heavily. After consultation with the Sealcentre, they took the seal to Eemshaven. There, we were ready to receive Irene.

The seal was a female about six months old. What was special about this animal is that she carried a tracking device on her back. The transmitter had been placed on Helgoland in the previous winter by an international research team and the research team has always been able to follow the seal via satellite. The transmitter had nothing to do with the entanglement.

Life on the open sea

She had already swum quite a distance for a young seal. The map which was made on the basis of the signal from her transmitter, clearly shows that Irene had mainly been swimming around the Dogger Bank in the previous two weeks. The Dogger Bank is a shallow area in the middle of the North Sea. It is a maximum of 35 meters deep and more than 200 kilometers north of the Dutch Wadden Islands.

We were surprised that such a young seal stays on the open sea for so long! The Dogger Bank is a good place for seals. Because of the relatively shallow water, they can hunt well. The Dogger Bank protrudes 25 meters above the surrounding seabed and is only 15 meters deep in certain places. But it also means that a lot of people fish. That brings a high risk of entanglement.

Irene's recovery

The first period in the rehablitiation centre is always uncertain. Especially when it comes to seals with serious injuries, like Irene. She also suffered from worms that can cause a lot of damage. Recovery was slow. After eleven days, Irene was moved to the outdoor pool.

In the beginning, attempts were made not to remove the transmitter. This kind of data is extremely interesting. At one point it was necessary to remove the transmitter from Irene's back. It really got in the way of the treatment of the wound in Irene's neck.

Released without a transmitter

The transmitter was stuck to her fur. To remove it, a piece was shaved off. After two months of recovery, Irene was ready to be released. But the fur wasn't long enough to replace the transmitter yet. Because the health of a seal always comes first, it has been decided to release Irene without a transmitter.

Completely healthy and strong again (but with a large scar on her neck from the fishing net) she was released. Back to the sea. Back to her home.

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