Shipwrecks, ascidians and modiolarca subpicta (Bivalvia, Mytildae, Musculinae)

The ovulid gastropod Xandarovula patula (Pennant, 1777) was found 14.vi.2011 on the soft coral Alcyonium digitatum Linnaeus, 1758 (Dead man’s fingers) during a dive in the central North Sea on the wreck ‘Jeanette Kristina’ on the Dutch Dogger Bank. Later on additional specimens were found, sometimes with egg-capsules, on A. digitatum again, at two locations on the Dutch Cleaver Bank. The species has previously been recorded from the Atlantic coast of southern Spain to the western end of The English Channel, with scattered records from the west coasts of Ireland and Britain, as far north as the Orkney’s. More recently it has been reported from most Irish coasts, several parts of the Scottish coast and also from some places in the North Sea. We here present the first record of X. patula for the Dutch part of the continental shelf. The specimens and their egg-capsules from both the Dogger Bank and Cleaver Bank, indicate that this species is autochthonous in the central North Sea

Recent findings of wild European flat oysters <i>Ostrea edulis</i> (Linnaeus, 1758) in Belgian and Dutch offshore waters: new perspectives for offshore oyster reef restoration in the southern North Sea

The European flat oyster, Ostrea edulis, is an emblematic and ecologically important species that was fished to virtual extinction in Belgian and Dutch waters in the 19th century. We report on recent findings of live specimens in Belgian and Dutch waters, an indication for the presence of O. edulis in these waters. Though small, these relict populations provide possibilities for natural recovery of O. edulis reefs in Belgian and Dutch waters, provided the oyster’s habitat requirements are restored (e.g., exclusion of bottom disturbance). We suggest investigating whether a natural, yet slow, recovery using fisheries closures and gravel bed restoration is a feasible alternative to the currently envisaged human-mediated re-introduction of O. edulis in the North Sea. We identify and address the challenge of O. edulis detection and identification as an important issue blurring the true presence and distribution of oysters

Ecological relevance of shipwrecks in the North Sea

This paper reports on observations made during wreck dive expeditions in 2010-2012, in order to investigate the ecological relevance of shipwrecks on the Dutch Continental Shelf (DCS). Shipwrecks are biodiversity hotspots. The number of species recorded on shipwrecks is similar to the number of species found in soft bottoms of the entire DCS. The soft substrates, however, represent a vastly larger habitat on the DCS than the shipwrecks. Amongst many other taxa, juvenile and large Atlantic cod, linear skeleton shrimp, goldsinny wrasses and leopard spotted gobies were found in the shipwreck habitats. The presence of these important species and their absence from many other habitats, illustrate that shipwrecks function as key habitats, nurseries, and refugia that are rare or absent anywhere else in the Netherlands

Marine fauna of hard substrata of the Cleaver Bank and Dogger Bank

As most of the sea bottom in the Dutch part of the North Sea consists of sand, marine fauna that live in association with hard substrates are rarely monitored. We report here on the results of a species inventory in June 2011 done by scuba-diving while focusing on a wreck on the Dogger Bank and on rocky bottoms on the Cleaver Bank. This resulted in various new records of species for the Dutch part of the North Sea. This result appeared for a large part linked to the added value of monitoring with scuba-divers. It is therefore concluded that scuba-divers should be used in addition to the more traditional monitoring methods in which dredges and grabs are used, if one aims at getting an accurate view of the biodiversity present in marine regions like the North Sea

The jewel anemone corynactis viridis, a new order for the Netherlands Cnidaria: Corallimorpharia)

During an expedition with scuba-divers to the Dutch part of the Brown Ridge in the central North Sea in June 2013, two colonies of the jewel anemone Corynactis viridis were found on the wreck Anna Graebe. With the jewel anemone both a new species and a new animal order, the Corallimorpharia, are added to the autochthonous fauna of the Netherlands. This species typically occurs in the Mediterranean and along the Atlantic coast from Portugal and the west British Isles up to Shetland. As other records of settled colonies of C. viridis in the North Sea were recently reported from Belgian, German and English waters, it is concluded that the jewel anemone, which used to be known as an occasional visitor, should now be considered autochthonous in the North Sea.

Waarneming effect bodemberoering op de Klaverbank

In juni 2017 is de 11e duikexpeditie op de Noordzee georganiseerd, door Stichting Duik de Noordzee Schoon. Op 18 juni werd er een duik gemaakt op het grind- en stenensubstraat van de Klaverbank, op locatie 54.021019 N / 3.165225 O, waterdiepte 38 meter (Bijlage 1 en 2). Van dit gebied is het bekend dat er veel stenen liggen (Leewis et al., 2015). Op de Klaverbank komen op deze natuurlijke harde substraten uitgebreide epifaunagemeenschappen voor, gedomineerd door koudwaterkoralen (dodemansduim)

Natuurwaarden Borkumse Stenen: project aanvullende beschermde gebieden

In dit rapport wordt de bodemfauna in het gebied ‘Borkumse Stenen’ beschreven. Het gebied ‘Borkumse Stenen’ ligt ten noorden van Schiermonnikoog en grenst aan de zuidzijde aan het Nederlandse Natura 2000-gebied Noordzeekustzone en aan de oostzijde aan het Duitse Natura 2000-gebied ‘Borkum Riffgrund’, dat o.a. vanwege de aanwezigheid van habitattype H1170 (‘riffen’) is aangewezen