Search

Between August 9th and October 27th the Dutch and Belgian beaches (Southern Bight of the North Sea) witnessed an unusual stranding of Aequorea spp. The northernmost sighting came from the Dutch Wadden Island of Ameland (9 September and 19 October), de southernmost from Raversijde, Belgium (18 August and 9 September). Strandings of Aequorea are infrequent and were often reported as A. vitrina. Unfortunately in the past, the distinction between A. forskalea and A. vitrina had not always been made and moreover identification of beached specimens is often not possible anymore due to decomposition of the animals. However during the recent stranding, surprisingly most individuals proved to be A. forskalea, until then considered as a rare species in the southern North Sea. Additionally, the recent sightings of Aequorea are validated and listed as well as all older sightings from Belgium and the Netherlands known to the authors.

The harbour porpoise Phocoena phocoena is currently the most abundant marine mammal in Belgian waters. Large-scale changes in the distribution of this top predator in the North Sea have occurred during the last decades, possibly caused by changes in food availability. An analysis of the strandings database 1970-2011, containing data on 737 harbour porpoises, revealed that throughout the year two peaks in strandings occurred: one in spring, for an important part caused by the strandings of animals incidentally bycaught in fishing gear, and a second one during summer. Most of the stranded animals were juveniles, with a higher percentage of males than females. As could be expected, bycaught animals were on average heavier than equally sized naturally died animals, and they had a thicker blubber layer. In naturally died animals the blubber layer was thicker in winter than in summer, illustrating the insulating function of the blubber layer besides its function as an energy storage.We investigated the stomach content of 64 harbour porpoises washed ashore or bycaught in Belgium between 1997 and 2011. Ten of the stomachs were empty. Fish contributed to most of the prey remains. In total we found the remains of 19 fish species belonging to 10 families. The numerically most important prey items in juveniles were gobies (Gobiidae). Reconstructing the original weight of the prey items revealed that gobies constituted the most important prey by weight, but that larger sandeels (Ammodytidae) and to a lesser extent gadoids (Gadidae) were also important. In adults the majority of prey items were gobies and sandeels, but the reconstructed weight of the stomach content revealed that sandeels and gadoids constituted by far the most important prey. Surprisingly, clupeids (Clupeidae) did not contribute much to the diet, although the return of the harbour porpoise is often linked to an increase in herring Clupea harengu stocks in the southern North Sea. Also no twaite shad Alosa fallax were found, although this diadromic fish is common again in the area. A small number of smelt Osmerus eperlanus was found in some of the recently stranded harbour porpoises. Smelt is a diadromic fish of which densities are increasing from very low levels. The fact that juvenile harbour porpoises had apparently fed on large quantities of small bottom fish may help to explain why they were more prone to bycatch than adults. The analysis revealed that a gradual shift occurs in the feeding habits of harbour porpoises while becoming adults: from small benthic fish towards larger fish taken from the water column.

In 1751 the corpse of a large whale was found floating at sea near Blankenberge (currently Belgium). The case was illustrated at the time by a water-colour of the whale and of an associated barnacle. In earlier publications, this whale has been regarded as a northern right whale (Eubalaena glacialis). However, morphological characteristics depicted in the original water-colour, published here for the first time, and in a copy of the original, point towards a humpback whale (Megaptera novaeangliae). Also, the illustrated barnacle can only represent Coronula diadema, a species typically associated with humpback whales. Thus, the case of a right whale in the southern North Sea in 1751, often cited because of the rarity of that species in this area by then, has to be deleted from the records. In this article also the size of the animal, the circumstances and the date are corrected with regard to the previous description of this record, and more information is given about the various artists to whom the water-colours can be attributed.

After a small amount of oil had leaked into the southern North Sea as a results of the collision between the oil tanker Vicky and the sunken car carrier Tricolor on 1 January 2003, 249 oiled birds (98% Guillemot Uria aalge and Razorbill Alca torda) were received at the Bird Rehabilitation Centre at Ostend, Belgium. Following a second larger oil spill during the salvage works of the Tricolor a few weeks later, in total 9,177 birds stranded at the Belgian coast during the period 23 January to 15 February. This time, virtually all birds were heavily oiled and more than half of the birds were still alive on arrival in Ostend. More than 90% of the victims were Guillemot and Razorbill; other species that accounted for more than 1% of the stranded birds were Great Crested Grebe Podiceps cristatus and Common Scoter Melanitta nigra. The birds stranded in three waves. A first peak in numbers (> 1,000 victims per day) occurred at 26 January and consisted of high proportions of Guillemots that managed to reach the coast alive despite unfavourable wind conditions. In the following weeks, the daily numbers of stranded birds were closely related to the prevailing wind conditions. The second and third peak in the number of strandings coincided with two periods of strong onshore winds. Changes in the species composition and the location where the birds were found are thought to reflect the movements of the oil slick perpendicular and parallel to the coastline, respectively. The proportion of Razorbills among the auks found during the incident greatly differed from that at sea and the proportion of dead birds was much higher among Razorbills than Guillemots. These differences can not be explained from differences in wintering areas. It is suggested that the third peak in strandings was at least partly related to a wreck among auks that was unrelated to the oil polluation.