scholarly journals Reconstructing three decades of total international trawling effort in the North Sea

2020 ◽  
Vol 12 (1) ◽  
pp. 373-386 ◽  
Author(s):  
Elena Couce ◽  
Michaela Schratzberger ◽  
Georg H. Engelhard
Keyword(s):  
North Sea ◽  
Large Scale ◽  
Information Source ◽  
Marine Ecosystem ◽  
Fishing Effort ◽  
Anthropogenic Pressures ◽  
The North ◽  
The North Sea ◽  
Long Term Impact

Abstract. Fishing – especially trawling – is one of the most ubiquitous anthropogenic pressures on marine ecosystems worldwide, yet very few long-term, spatially explicit datasets on trawling effort exist; this greatly hampers our understanding of the medium- to long-term impact of trawling. This important gap is addressed here for the North Sea, a highly productive shelf sea which is also subject to many anthropogenic pressures. For a 31-year time span (1985–2015), we provide a gridded dataset of the spatial distribution of total international otter and beam trawling effort, with a resolution of 0.5∘ latitude by 1∘ longitude, over the North Sea. The dataset was largely reconstructed using compiled effort data from seven fishing effort time series, each covering shorter time spans and only some of the countries fishing the North Sea. For the years where effort data for particular countries were missing, the series was complemented using estimated (modelled) effort data. This new, long-term and large-scale trawling dataset may serve the wider scientific community, as well as those involved with policy and management, as a valuable information source on fishing pressure in a large marine ecosystem which is heavily impacted but which simultaneously provides a wealth of ecosystem services to society. The dataset is available on the Cefas Data Hub at: https://doi.org/10.14466/CefasDataHub.61, version 2 (Couce et al., 2019).

scholarly journals Reconstructing three decades of total international trawling effort in the North Sea

2019 ◽  
Author(s):  
Elena Couce ◽  
Michaela Schratzberger ◽  
Georg H. Engelhard
Keyword(s):  
North Sea ◽  
Large Scale ◽  
Information Source ◽  
Marine Ecosystem ◽  
Fishing Effort ◽  
Anthropogenic Pressures ◽  
The North ◽  
The North Sea ◽  
Long Term Impact

Abstract. Fishing – especially trawling – is one of the most ubiquitous anthropogenic pressures on marine ecosystems worldwide, yet very few long-term, spatially explicit datasets on trawling effort exist; this greatly hampers our understanding of the medium- to long-term impact of trawling. This important gap is addressed here for the North Sea, a highly productive shelf sea which is also subject to many anthropogenic pressures. For a 31-year time span (1985–2015), we provide a dataset on the spatial distribution of total international otter and beam trawling effort, for all ICES rectangles (0.5° latitude by 1° longitude) of the North Sea. The dataset was largely reconstructed using compiled effort data from 7 fishing effort time-series, each covering shorter time spans and some of the countries fishing the North Sea only. For the years where effort data for particular countries were missing, the series was complemented using estimated (modelled) effort data. This new, long-term and large-scale trawling dataset may serve the wider scientific community, as well as those involved with policy and management, as a valuable information source on fishing pressure in a Large Marine Ecosystem which is heavily impacted, but which simultaneously provides a wealth of ecosystem services to society. The dataset is available on the Cefas Data Hub at: https://doi.org/10.14466/CefasDataHub.61 (Couce et al., 2019).

Change in the North Sea ecosystem from the 1970s to the 2010s: great skua diets reflect changing forage fish, seabirds, and fisheries

2018 ◽  
Vol 76 (4) ◽  
pp. 925-937 ◽  
Author(s):  
Gabriella E Church ◽  
Robert W Furness ◽  
Glen Tyler ◽  
Lucy Gilbert ◽  
Stephen C Votier
Keyword(s):  
North Sea ◽  
Anthropogenic Impacts ◽  
Marine Ecosystem ◽  
Commercial Fishing ◽  
Seabird Species ◽  
Rissa Tridactyla ◽  
Fulmarus Glacialis ◽  
The North ◽  
The North Sea

Abstract Understanding anthropogenic impacts are crucial to maintain marine ecosystem health. The North Sea has changed in recent decades, largely due to commercial fishing and climate change. Seabirds can act as useful indicators of these changes. By analyzing n = 20 013 pellets and n = 24 993 otoliths regurgitated by great skuas Stercorarius skua in northern Scotland over five decades from the 1970s to the 2010s (in 36 years 1973–2017), we reveal how the diet of this top predator has changed alongside the changing North Sea ecosystem. Sandeels Ammodytes spp. were the most common dietary item during the 1970s, but became virtually absent from the 1980s onward. Discarded whitefish dominated skua diets from the 1980s to the present day, despite long-term declines in North Sea discard production. However, the discarded fish eaten by great skuas has become smaller and the species composition changed. Skua pellets only rarely contained avian prey in the 1970s but this increased during the 1980s, and fluctuated between 10% and 20% from the 1990s to 2010s. There have also been changes in the avian prey in the diet—black-legged kittiwakes Rissa tridactyla generally being replaced by auks Alcid spp. and northern fulmars Fulmarus glacialis. The Shetland marine ecosystem has experienced steep declines in sandeel stocks and in seabirds that feed on them. Great skuas have been able to prey switch to respond to this change, supported by abundant discards, enabling them to maintain a favourable population status while other seabird species have declined.

scholarly journals Long-term Behavior of CO2 Stored on a Large Scale in the Utsira Formation, the North Sea, Norwegian Continental Shelf

2013 ◽  
Vol 37 ◽  
pp. 5240-5247
Author(s):  
V.T.H. Pham ◽  
E.K. Halland ◽  
I.M. Tappel ◽  
I.T. Gjeldvik ◽  
F. Riis ◽  
...  
Keyword(s):  
Continental Shelf ◽  
North Sea ◽  
Large Scale ◽  
The North ◽  
The North Sea ◽  
Long Term Behavior ◽  
Norwegian Continental Shelf

scholarly journals Spatial and Temporal Analysis of Cumulative Environmental Effects of Offshore Wind Farms in the North Sea Basin

2020 ◽  
Author(s):  
Laura Gusatu ◽  
Stefano Menegon ◽  
Daniel Depellegrin ◽  
Christian Zuidema ◽  
André Faaij ◽  
...  
Keyword(s):  
Environmental Impacts ◽  
North Sea ◽  
Large Scale ◽  
Marine Ecosystem ◽  
Wind Farms ◽  
Temporal Analysis ◽  
Offshore Wind ◽  
Offshore Wind Farms ◽  
The North ◽  
The North Sea

Abstract The North Sea basin is one of the busiest maritime areas globally with a considerable number of anthropogenic pressures impacting the functioning of the marine ecosystem. Due to growing EU ambitions for the deployment of large-scale offshore wind farms (OWF), as part of the 2050 renewable energy roadmap, there is a key need for a holistic understanding of OWF potential impacts on the marine ecosystem. We propose a holistic Cumulative Effect Assessment methodology, applied using a geo-spatial open-source software, to assess impacts of OWF related pressures on selected seabed habitats, fish, seabird and mammal species. We take into account pressures specific to the three OWF development phases, spanning 1999–2050, for the entire North Sea basin. Our results underline 2022 as the peak year of cumulative impacts for the approved OWFs, followed by a considerable increase in potential impacts of the planned 212GWs, by 2050. The spatio-temporal analysis of the OWF environmental impacts presents the shift between highly impacted areas over the studied timeline and distinguishes between concentrated areas of high impacts (S-E of UK) and dispersed areas of high impacts (Germany). Our results can inform decision-makers and the OWF industry in a joint effort to mitigate the environmental impacts of future large-scale OWF developments.

scholarly journals Changes in the North Sea fish community: evidence of indirect effects of fishing?

2005 ◽  
Vol 62 (2) ◽  
pp. 177-188 ◽  
Author(s):  
Niels Daan ◽  
Henrik Gislason ◽  
John G. Pope ◽  
Jake C. Rice
Keyword(s):  
North Sea ◽  
Indirect Effects ◽  
Fish Community ◽  
Fishing Effort ◽  
Time Lags ◽  
The North ◽  
Exploitation Rate ◽  
The North Sea ◽  
Sea Fish

Abstract We investigate changes in the North Sea fish community with particular reference to possible indirect effects of fishing, mediated through the ecosystem. In the past, long-term changes in the slope of size spectra of research vessel catches have been related to changes in fishing effort, but such changes may simply reflect the cumulative, direct effects of fishing through selective removal of large individuals. If there is resilience in a fish community towards fishing, we may expect increases in specific components, for instance as a consequence of an associated reduction in predation and/or competition. We show on the basis of three long-term trawl surveys that abundance of small fish (all species) as well as abundance of demersal species with a low maximum length (Lmax) have steadily and significantly increased in absolute numbers over large parts of the North Sea during the last 30 years. Taking average fishing mortality of assessed commercial species as an index of exploitation rate of the fish community, it appears that fishing effort reached its maximum in the mid-1980s and has declined slightly since. If the observed changes in the community are caused by indirect effects of fishing, there must be a considerable delay in response time, because the observed changes generally proceed up to recent years, although both size and Lmax spectra suggest some levelling off, or even recovery in one of the surveys. Indeed, significant correlations between all community metrics and exploitation rate were obtained only if time lags ≥6 years were introduced.

scholarly journals The long-term variability of extreme sea levels in the German Bight

2019 ◽  
Author(s):  
Andreas Lang ◽  
Uwe Mikolajewicz
Keyword(s):  
Sea Level ◽  
North Sea ◽  
German Bight ◽  
Large Scale ◽  
Climate System ◽  
Tide Gauge Record ◽  
Sea Levels ◽  
The North ◽  
The North Sea

Abstract. We investigate the long-term variability of extreme high sea levels (ESL) in the southern German Bight and associated large-scale forcing mechanisms in the climate system using simulations covering the last 1000 years. To this end, global MPI-ESM simulations from the PMIP3 past1000 project are dynamically scaled-down with a regionally coupled climate system model focusing on the North Sea. We find that the statistics of simulated ESL compare well with observations from the tide gauge record at Cuxhaven but show large variations on interannual to centennial timescales. ESL arise independent of preferred systematic oscillations and are to a large extent decoupled from variations of the background sea level (BSL). Large scale circulation regimes associated with periods of high ESL are regionally consistent and similar to those associated with elevated BSL, but the location of the respective centers of action of the governing sea level pressure (SLP) dipole differs. While BSL variations correlate well with the wintertime North Atlantic Oscillation (NAO), ESL variations are rather associated with a dipole between northeastern Scandinavia and the Gulf of Biscay, leading to a stronger local north-westerly wind component in the North Sea. Potential links with solar or volcanic forcing are masked due to the high ESL variability. The high internal variability stresses the irreducible uncertainties related to traditional extreme value estimates based on shorter subsets which fail to account for long-term variations. Existing estimates of future changes in ESL may be dominated by natural variability rather than climate change signals, thus requiring larger ensemble simulations to assess future flood risks.

Offshore Claims and Problems in the North Sea

1965 ◽  
Vol 59 (3) ◽  
pp. 505-522 ◽  
Author(s):  
Richard Young
Keyword(s):  
North Sea ◽  
Large Scale ◽  
Geneva Convention ◽  
Legal Principles ◽  
The North ◽  
Legal Problems ◽  
The North Sea ◽  
The Subject ◽  
First Time ◽  
Economic Considerations

The possible presence of very large petroleum and natural gas reserves in the area beneath the North Sea is currently the subject of intense investigation. If confirmed, as seems likely in at least some localities, this occurrence will raise legal problems of considerable interest and complexity. For the North Sea is not merely an oilfield covered by water: for centuries it has been one of the world's major fishery regions and the avenue to and from the world's busiest seaports. Thus all three of the present principal uses of the sea—fishing, navigation, and the exploitation of submarine resources—promise to meet for the first time on a large scale in an area where all are of major importance. The process of reconciling the various interests at stake will provide the first thoroughgoing test of the adequacy and acceptability of the general principles laid down in the 1958 Geneva Convention on the Continental Shelf and should add greatly to the practice and precedents available in this developing branch of the law. In the present article an attempt is made to review some of the geographical and economic considerations involved in the North Sea situation, to note some of the technical and legal developments that have already taken place, and to consider these elements in the light of the various interests and legal principles concerned.

scholarly journals Long-term series in ichthyoplankton: sole and sprat at French coast of the North Sea from 1975 to 1994

1998 ◽  
Vol 21 (1) ◽  
pp. 113-121 ◽  
Author(s):  
Daniel Woehrling ◽  
Geneviève Le Fèvre-Lehoërff
Keyword(s):  
North Sea ◽  
The North ◽  
The North Sea
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