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

2018 ◽  
Vol 148 (1) ◽  
Author(s):  
Francis Kerckhof ◽  
Joop W.P. Coolen ◽  
Bob Rumes ◽  
Steven Degraer
Keyword(s):  
North Sea ◽  
Ostrea Edulis ◽  
Important Species ◽  
Reef Restoration ◽  
The North ◽  
Detection And Identification ◽  
The North Sea ◽  
Feasible Alternative ◽  
Flat Oyster ◽  
The 19Th Century

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.

scholarly journals Ostrea edulis beds in the central North Sea: delineation, ecology, and restoration

2020 ◽  
Author(s):  
Floris P Bennema ◽  
Georg H Engelhard ◽  
Han Lindeboom
Keyword(s):  
North Sea ◽  
Cold Water ◽  
Feasibility Studies ◽  
Reproductive Rate ◽  
Ostrea Edulis ◽  
The North ◽  
Key Species ◽  
The North Sea ◽  
Flat Oyster ◽  
Central North Sea

Abstract Until the late 19th century, extensive beds of flat oyster Ostrea edulis populated the Central North Sea, which have vanished after intensive fisheries. At present, various initiatives are being carried out to investigate the potential to restore this former key species in the area. This historical ecological study contributes by delineating the former oyster bed area and through an assessment of its limits against known gradients in the North Sea. Extensive data from historical maps, texts, and ship-based surveys were used to synthesize our knowledge on the former beds. It was revealed that the area with oyster beds covered ∼6.2% of the total North Sea bottom, with a delineation that could partly be explained by hydrodynamic and temperature gradients. The position and extent of the area are notably different from the area that is used in recent feasibility studies on the restoration of North Sea oyster beds. The offshore oysters lived on muddy sand in relatively cold conditions, and there are several indications that their reproductive rate was low. The apparent disappearance of cold water adapted flat oysters will challenge restoration projects. This study provides indispensable information for the future restoration of flat oyster beds in the North Sea.

scholarly journals Offshore Wind Farms as Potential Locations for Flat Oyster (Ostrea edulis) Restoration in the Dutch North Sea

2018 ◽  
Vol 10 (11) ◽  
pp. 3942 ◽  
Author(s):  
Pauline Kamermans ◽  
Brenda Walles ◽  
Marloes Kraan ◽  
Luca van Duren ◽  
Frank Kleissen ◽  
...  
Keyword(s):  
North Sea ◽  
Renewable Energy Sources ◽  
Wind Farms ◽  
Offshore Wind ◽  
Ecosystem Functions ◽  
Ostrea Edulis ◽  
The North ◽  
The North Sea ◽  
Flat Oyster ◽  
Oyster Restoration

The “Dutch Energy Agreement” motivates governments and industries to invest in renewable energy sources, of which offshore wind energy is one of the solutions to meet the agreed target of 16% of the total energy budget from renewable resources by 2023. An option for the multi-use of wind farms is nature-inclusive building, in which the design and construction of wind farms make use of the potential for co-design with oyster bed restoration. This can support the government’s ambitions, for the Dutch North Sea, to achieve biodiversity goals, restore ecosystem functions, and enhance ecosystem services, including future seafood production. For the recovery of flat oyster (Ostrea edulis) beds, knowledge is required about the conditions under which active restoration of this species in the North Sea can be successfully implemented. This paper gives a framework and presents results to determine suitability of wind farms for flat oyster restoration, and provides recommendations for pilot studies. Our analysis showed that a number of wind farms in the Dutch section of the North Sea are suitable locations for development of flat oyster beds. Combining oyster restoration and oyster culture, as a protein source, is a viable option worth investigating.

scholarly journals The late Holocene demise of a sublittoral oyster bed in the North Sea

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0242208
Author(s):  
Lasse Sander ◽  
H. Christian Hass ◽  
Rune Michaelis ◽  
Christopher Groß ◽  
Tanja Hausen ◽  
...  
Keyword(s):  
North Sea ◽  
Size Structure ◽  
Focal Point ◽  
Land Use Changes ◽  
Ostrea Edulis ◽  
The North ◽  
Boring Sponge ◽  
Spatial Dimensions ◽  
The North Sea ◽  
Flat Oyster

A fossil oyster bed (Ostrea edulis) was recently encountered offshore Helgoland (German Bight). Oysters are important filter feeders in marine environments and their habitat structure supports a large associated biodiversity. The European flat oyster Ostrea edulis has historically occurred in vast populations in the North Sea, but declined massively in the early 20th century. The ecological restoration of Ostrea habitats is a current focal point in the North Sea. To better understand the mechanisms that caused the local collapse of the oyster population, this study investigated the size structure, weight, and age of the shells, along with the spatial dimensions, seafloor properties, and environmental context of the oyster bed. The results show that the demise of the population occurred around 700 CE, ruling out excessive harvest as a driver of decline. Synchronicity of increased geomorphological activity of rivers and concurrent major land use changes in early medieval Europe suggest that increased sedimentation was a viable stressor that reduced the performance of the oysters. The shells provided no indication of a demographically poor state of the oyster bed prior to its demise, but manifested evidence of the wide-spread occurrence of the boring sponge Cliona sp. Our study challenges the assumption of a stable preindustrial state of the European flat oyster in the North Sea, and we conclude that the long-term variability of environmental conditions needs to be addressed to benchmark success criteria for the restoration of O. edulis.

scholarly journals The Algicidal Bacterium Kordia algicida Shapes a Natural Plankton Community

2019 ◽  
Vol 85 (7) ◽  
Author(s):  
Arite Bigalke ◽  
Nils Meyer ◽  
Lydia Alkistis Papanikolopoulou ◽  
Karen Helen Wiltshire ◽  
Georg Pohnert
Keyword(s):  
North Sea ◽  
Algal Blooms ◽  
Plankton Community ◽  
Algicidal Bacteria ◽  
Important Species ◽  
Substantial Impact ◽  
The North ◽  
Algicidal Bacterium ◽  
The North Sea ◽  
Plankton Communities

ABSTRACT Plankton communities consist of complex microbial consortia that change over time. These fluctuations can be only partially explained by limiting resources. Biotic factors such as herbivores and pathogens also contribute to the control of algal blooms. Here we address the effects of algicidal bacteria on a natural plankton community in an indoor enclosure experiment. The algicidal bacteria, introduced into plankton taken directly from the North Sea during a diatom bloom, caused the rapid decline of the bloom-forming Chaetoceros socialis within only 1 day. The haptophyte Phaeocystis, in contrast, is resistant to the lytic bacteria and could benefit from the removal of the competitor, as indicated by an onset of a bloom in the treated enclosures. This cascading effect caused by the bacterial pathogen accelerated the succession of Phaeocystis, which bloomed with a delay of only several weeks in the in situ waters at Helgoland Roads in the North Sea. The algicidal bacteria can thus modulate the community within the limits of the abiotic and biotic conditions of the local environment. Implications of our findings for plankton ecosystem functioning are discussed. IMPORTANCE Plankton communities change on a seasonal basis in temperate systems, with distinct succession patterns; this is mainly due to algal species that have their optimal timing relative to environmental conditions. We know that bacterial populations are also instrumental in the decay and termination of phytoplankton blooms. Here, we describe algicidal bacteria as modulators of this important species succession. Upon treatment of a natural plankton consortium with an algicidal bacterium, we observed a strong shift in the phytoplankton community structure, compared to controls, resulting in formation of a succeeding Phaeocystis bloom. Blooms of this alga have a substantial impact on global biogeochemical and ecological cycles, as they are responsible for a substantial proportion of primary production during spring in the North Sea. We propose that one of the key factors influencing such community shifts may be algicidal bacteria.

scholarly journals First report of an idiopathic partial tail myonecrosis in European brown shrimp Crangon crangon caught in the North Sea

2020 ◽  
Vol 138 ◽  
pp. 35-40
Author(s):  
XHC Vermeersch ◽  
A Decostere ◽  
G Vlaemynck ◽  
K Chiers
Keyword(s):  
North Sea ◽  
Distal Part ◽  
Brown Shrimp ◽  
Bacterial Invasion ◽  
Microscopical Examination ◽  
Necrotic Tissue ◽  
Crangon Crangon ◽  
Important Species ◽  
The North ◽  
The North Sea

The European brown shrimp Crangon crangon is an abundant and commercially important species in the North Sea. Currently, there is interest in landing live shrimp to provide fresh animals for a growing market in live brown shrimp. During 4 survival studies between 2014 and 2016, shrimp were collected from commercial trawlers and maintained alive in off-shore facilities. From Day 1 onwards, a minority of shrimp (~2.24%) developed a white discoloration of the abdominal muscles and a depigmentation of the distal part of the abdomen, along with paralysis of the affected tissues and appendages. As the symptoms progressed, a circumferential blackish delineation appeared, creating a distinct boundary between healthy and necrotic tissue. Affected shrimp survived up to 3 wk, although in several animals the distal part of the tail was completely lost. Histological and electron microscopical examination confirmed the myonecrosis. A secondary bacterial invasion of the necrotic muscle was observed in some animals. RT-PCR for infectious myonecrosis virus was negative. The condition appears not to be contagious, based on the feeding of healthy shrimp with necrotic tissue of affected shrimp. Based on these observations, a mechanical cause inflicted during the catching process is proposed.

scholarly journals Lactuca tatarica (Asteraceae) in embryonic dunes on Wolin Island (NW Poland)

2015 ◽  
Vol 39 (1) ◽  
pp. 61-66 ◽  
Author(s):  
Wojciech Kowalski W. A. ◽  
Andrzej Łysko ◽  
Agnieszka Popiela
Keyword(s):  
Baltic Sea ◽  
19Th Century ◽  
North Sea ◽  
Natural Habitat ◽  
The North ◽  
The North Sea ◽  
The 19Th Century ◽  
First Time ◽  
Nw Poland

Abstract By the end of the 19th century, Lactuca tatarica was reported for the first time from an adventive occurrence on the North Sea and Baltic Sea coasts. In Wolin Island, the species has become established in the natural habitat and is clearly spreading in recent years. The community with L. tatarica was studied currently on the western point of Wolin Island along the stretch between the mouth of the Świna (Swine) River and a newly constructed breakwater of the external harbour. The taxon occupies relatively low parts of the sandy elevations of dune ridges, in patches of the Honckenyo-Agropyretum juncei association (habitat 2110). Furthermore, L. tatarica has been reported in recent years from some locations in Świnoujście (Usedom (Uznam) Island), Międzyzdroje, Wisełka and Międzywodzie.

scholarly journals A new balaenopterid species from the Southern North Sea Basin informs about phylogeny and taxonomy of Burtinopsis and Protororqualus (Cetacea, Mysticeti, Balaenopteridae)

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9570 ◽  
Author(s):  
Michelangelo Bisconti ◽  
Mark E.J. Bosselaers
Keyword(s):  
Phylogenetic Analysis ◽  
New Species ◽  
Atlantic Ocean ◽  
North Sea ◽  
North Atlantic Ocean ◽  
The Past ◽  
The North ◽  
The North Sea ◽  
Morphological Transformations ◽  
The 19Th Century

Background An extensive radiation can be inferred among balaenopterid mysticetes in the last 10 million years based on a rich fossil record. Many extinct genera and species have been established in the past by the study of fossil rorquals from northern and southern hemispheres. In many cases, the new fossils are used to create new genera. However, in very recent times, new species of known genera have been described that help our understanding of the speciation processes and the biogeography of these whales. Here, a new species of balaenopterid whales is described in order to better understand the past diversity of Balaenopteridae and to analyze its paleobiogeographical implications. As the new species closely resembles a taxon established in the 19th century (i.e., Burtinopsis), a detailed analysis of this taxon was necessary to support the new taxonomic statements of this article. Methods A new partial skeleton including skull and earbones is described and compared to an extended sample of living and fossil mysticete species. A phylogenetic analysis including 355 character states scored in 88 taxa was performed to understand its relationships within the genus Protororqualus, to allow paleobiogeographic inferences and to better understand the relationships of Protororqualus within Balaenopteridae. Maximum parsimony analyses of character evolution were performed to understand morphological transformations within Balaenopteridae. The revision of Burtinopsis was carried out based on detailed descriptions and comparisons of the type materials that were figured and measured. Results Protororqualus wilfriedneesi sp. nov. was established based on a comparative analysis of the skull and earbone morphology. The specimen is dated back to the Zanclean (Lower Pliocene, between c. 5.3 and 3.6 Ma). A taphonomical study of the holotype skeleton revealed evidence of interactions with sharks and fishes before the definitive burial of the carcass. Based on the phylogenetic analysis, the monophyly of the genus Protororqualus was confirmed. Protororqualus wilfriedneesi sp. nov. was more derived than Protororqualus cuvieri suggesting that it resulted from an invasion of the North Sea Basin (and the North Atlantic ocean) from the Mediterranean basin. Several specimens from western and eastern sides of the Atlantic Ocean are described that suggest that Protororqualus wilfriedneesi had a trans-Atlantic distribution in the Pliocene.

The sea as a dynamic and hybrid landscape

2011 ◽  
Author(s):  
Robert Van de Noort
Keyword(s):  
North Sea ◽  
Late Glacial ◽  
Sea Level Changes ◽  
The North ◽  
History Of Research ◽  
Research Activities ◽  
Dynamic Landscape ◽  
History Of ◽  
The North Sea ◽  
The 19Th Century

Since the last glacial maximum, some 22,000 years ago, the North Sea basin has undergone many transformational changes. Largely covered by ice at the beginning of the period, it became successively an arctic-like tundra, a ‘park-like’ landscape of extended grassland with shrubs and trees, a tundra again, and a plain with light woodland cover that was submerged eventually by the expanding North Sea (Coles 1998: 69–75). As the North Sea rose, over the last 5,000 years, to within a few metres of its current level, the interior of the sea did not alter significantly apart from changes in tidal patterns and depth. But on the periphery of the North Sea basin, the slighter sea-level changes added to the effects of marine and alluvial sedimentation and erosion and produced, regionally, periods of marine transgression—when the influence of the sea moved landwards—and marine regression, resulting in the opposite effect. The North Sea, throughout its history, has been the dynamic landscape par excellence. The history of research into the North Sea basin goes back to the 19th century, and will be discussed further below, but it was Bryony Coles’ article ‘Doggerland: a speculative survey’ (1998), which first raised the profile of the Late-glacial and early Holocene archaeology of the North Sea and inspired many of the current research activities, especially those relating to the southern North Sea basin. The renewed interest in the Mesolithic and Neolithic archaeology of the North Sea has made some significant advances, and holds the promise of even greater returns once the high-resolution reconstructions of the North Sea Plain are integrated with the archaeological finds. A series of publications has recently presented new archaeological sites. New finds from trawler fishing along the various banks in the North Sea, and from the margins (e.g. Flemming 2004; Waddington and Pedersen 2007), as well as the use of SCUBA technology (e.g. in Fisher 1995), will be discussed below. This chapter offers brief overviews of the history of North Sea research, the creation of the North Sea, and the archaeological evidence of human activity in the period from about 10,000 to 2000 cal bc.

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