Marine mammals in Belgium in 2016



Narwhal washed ashore along the Scheldt river in Bornem (28 april 2016).
Marine mammals in Belgium in 2016
post by
Kelle Moreau

In a new annual report, our scientists collect the available information on marine mammals in Belgium in 2016. Apart from an overview of marine mammals and remarkable fish washed ashore, it also focusses on the causes of death, revalidation and release of animals that were taken into care, and briefly introduces the research on the influence of offshore windmill parks on the harbour porpoise.

Rare guests

The most remarkable sightings of marine mammals in 2016 concerned two humpback whales (Megaptera novaeangliae) and a narwhal (Monodon monoceros). ‘The appearance of humpback whales off our coast does not come as a surprise: there is an increasing trend in the number of sightings of this species in the North Sea.’ says Jan Haelters, lead author of the report. ‘It’s a different story for the narwhal. This was the first narwhal ever reported in Belgium, and the previous North Sea record of this arctic species dates back almost 70 years. There may be a connection with climate change and the melting polar ice’. The narwhal was observed alive in the river Scheldt on 30 March, its decomposed remains were discovered on 27 April at Bornem and collected by our institute for further research. Aside from marine mammals, also some remarkable fish washed ashore: a live basking shark (Cetorhinus maximus) and two ocean sunfishes (Mola mola).


With 137 animals, the number of harbour porpoises (Phocoena phocoena) that washed ashore again reached the record level of 2013-2014. ‘The state of decomposition didn’t allow for an identification of the cause of death in almost two thirds of the cases. For the other animals, incidental catch and predation by grey seals (Halichoerus grypus) were the major causes of death.’ according to Haelters. On the other hand, the number of observations of harbour porpoises in effort-related surveys was relatively low. In relation to the offshore wind turbines, of which 232 were installed in the Belgian waters by early 2017, it was established that porpoises were disturbed during the construction phase.

Dolphins and seals

White-beaked dolphins (Lagenorhynchus albirostris) were reported on one day only, in contrast to bottlenose dolphins (Tursiops truncatus), which were regular guests again. In April, a bottlenose dolphin washed ashore, followed a few days later by a heavily decomposed dolphin at Hemiksem (Scheldt). The species could not be determined anymore.

The number of strandings of dead and dying seals remained similar to previous years: six harbour seals (Phoca vitulina), 11 grey and 12 unidentified seals. SEA LIFE Blankenberge took care of record high numbers: 15 grey and 24 common seals, including an albino animal. No less than 12 grey and 20 common seals could be returned to the wild after revalidation.


This report describes part of the implementation of the Belgian Royal Decree on Marine Species Protection, and could only be composed thanks to many volunteers that report their observations and with the support of multiple local order and emergency services. Interested readers can download the report here. This site also contains an overview of observations of living and stranded marine mammals, as well as a brochure describing protocols for reporting observations, strandings and incidental catches of protected marine species (only in Dutch).


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