scholarly journals Investigating fish migration, mortality, and physiology to improve conservation planning of anadromous salmonids: a case study on the endangered North Sea houting (Coregonus oxyrinchus)

2019 ◽  
Vol 97 (12) ◽  
pp. 1126-1136
Author(s):  
M. Hertz ◽  
L.F. Jensen ◽  
C. Pertoldi ◽  
K. Aarestrup ◽  
S.N. Thomsen ◽  
...  
Keyword(s):  
North Sea ◽  
Conservation Planning ◽  
Coregonus Lavaretus ◽  
The European Union ◽  
Habitat Directive ◽  
River Temperature ◽  
The North ◽  
Spawning Areas ◽  
The North Sea ◽  
Post Spawning

Understanding migratory behavior, mortality, and physiology is essential for conservation of many species, particularly anadromous fish. In this study, freshwater and marine migrations of the endangered salmonid North Sea houting (Coregonus oxyrinchus (Linnaeus, 1758)) were investigated using telemetry. Furthermore, physiological samples were collected from North Sea houting and from resident and anadromous populations of the closely related European whitefish (Coregonus lavaretus (Linnaeus, 1758)) to compare hypo-osmotic tolerances. On average, North Sea houting spent 193 days at sea where the mortality was 36%. Most fish returned from sea in the autumn, and river entry correlated inversely with river temperature and positively with discharge. Fish spent an average of 49 days in the estuarine area. Artificial lakes negatively affected migration speeds. Migration speeds did not differ consistently between individuals (i.e., not a repeatable trait) but correlated positively with water temperature. Fish arrived at spawning areas in November. In the post-spawning state, Na+/K+-ATPase activities were elevated in North Sea houting and anadromous whitefish compared with resident whitefish, while osmolality was elevated only in North Sea houting. Our study provides important information for conservation planning related to the Habitat Directive of the European Union that lists the North Sea houting as critically endangered.

Unconventional hydrocarbon resource plays in the North Sea Basin, Northwestern Europe

2020 ◽  
Author(s):  
Niels Schovsbo ◽  
Stefan Ladage ◽  
Anders Mathiesen ◽  
Susanne Nelskamp ◽  
Margaret A. Stewart ◽  
...  
Keyword(s):  
North Sea ◽  
Hydrocarbon Exploration ◽  
Organic Carbon Content ◽  
The European Union ◽  
Shale Formations ◽  
The North ◽  
Geological Surveys ◽  
Alum Shale ◽  
Hydrocarbon Resource ◽  
The North Sea

<p>In 2017 the geological surveys contributed to the European wide project ‘EU Unconventional Oil and Gas Assessment’ (EUOGA). The goal of EUOGA was to assess all potentially prospective shale formations from the main onshore basins in Europe and included contributions of twenty-one European geological surveys and the assessment covered 82 geological formations from 38 basins (Zijp et al. 2017).</p><p>To extend the assessment to offshore basins the geological surveys of Denmark (GEUS), Germany (BGR), the Northlands (TNO) and United Kingdom (BGS) are working together on the Geological Analysis and Resource Assessment of selected Hydrocarbon systems (GARAH) project that aims at assessing the conventional and unconventional hydrocarbon resource in the North Sea Basin. Within the basin more than 10 shale layers have been recognised as holding potential resources. These shales include the offshore equivalent of the Cambrian Alum Shale, The Carboniferous Bowland shale and the Jurassic Wealden and Kimmeridge shales that onshore have been a target for hydrocarbon exploration within the European Union member states. Each shale layer will be characterized using thirty systematic parameters such as areal distribution, structural setting, average net to gross ratio of the shale reservoir, average Total Organic Carbon content (TOC) and average mineralogical composition.</p><p>This is a part of an ongoing EU Horizon 2020 GeoERA project (The GARAH, H2020 grant #731166 lead by GEUS).</p><p>References</p><p>Zijp, M., Nelskamp, S., Schovsbo, N.H., Tougaard, L. & Bocin-Dumitriu, A. 2017: Resource estimation of eighty-two European shale formations. Proceedings of the 5th Unconventional Resources Technology Conference, Austin, Texas, USA, 24–26 July, 2017. https://doi.org/10.15530/urtec-2017-2686270</p>

scholarly journals Do Norway pout (Trisopterus esmarkii) die from spawning stress? Mortality of Norway pout in relation to growth, sexual maturity, and density in the North Sea, Skagerrak, and Kattegat

2012 ◽  
Vol 69 (2) ◽  
pp. 197-207 ◽  
Author(s):  
J. Rasmus Nielsen ◽  
Gwladys Lambert ◽  
Francois Bastardie ◽  
Henrik Sparholt ◽  
Morten Vinther
Keyword(s):  
North Sea ◽  
Sexual Maturity ◽  
Life History Traits ◽  
Trawl Survey ◽  
Older Individuals ◽  
Fishing Activity ◽  
The North ◽  
Spawning Areas ◽  
The North Sea ◽  
New Evidence

Abstract Nielsen, J. R., Lambert, G., Bastardie, F., Sparholt, H., and Vinther, M. 2012. Do Norway pout (Trisopterus esmarkii) die from spawning stress? Mortality of Norway pout in relation to growth, sexual maturity, and density in the North Sea, Skagerrak, and Kattegat. – ICES Journal of Marine Science, 69: 197–207. The mortality patterns of Norway pout (NP) are not well understood. It has been suggested that NP undergo heavy spawning mortality, and this paper summarizes and provides new evidence in support of this hypothesis. The very low–absent fishing activity in recent years provides a unique opportunity to analyse the natural life-history traits of cohorts in the NP stock in the North Sea. Based on the ICES trawl survey abundance indices, cohort mortality is found to significantly increase with age. We argue that this cannot be explained by selectiveness in the fishery, potential size-specific migrations out of the area, higher predation pressure on older individuals, or differences in survey catchability by NP age from before to after spawning and that it is higher in the main spawning areas than outside. We found that natural mortality (M) is significantly correlated with sexual maturity, sex, growth, and intraspecific stock density. All of this is consistent with a greater mortality occurring mainly from the first to the second quarter of the year, i.e. spawning mortality, which is discussed as being a major direct and indirect cause of stock mortality.

Nitrogen pollution in the European Union – origins and proposed solutions

1996 ◽  
Vol 23 (2) ◽  
pp. 120-132 ◽  
Author(s):  
Ester van der Voet ◽  
René Kleijn ◽  
Helias A. Udo de Haes
Keyword(s):  
European Union ◽  
Atmospheric Deposition ◽  
Ground Water ◽  
North Sea ◽  
Emission Reduction ◽  
Agricultural Practice ◽  
The European Union ◽  
The North ◽  
The North Sea ◽  
N Compounds

SummaryThe European Union is faced with major environmental problems related to nitrogen (N) compounds. The origins of three such problems, the atmospheric deposition of N compounds, the leaching of nitrates to ground-water and the anthropogenic N-input to the North Sea, are investigated by means of a Substance Flow Analysis (SFA); the reference year is 1988. Although the problems occur at various scales and have varying direct causes, food production and consumption together are the main responsible sectors, and the production and import of fertilizer appear to be the major ultimate sources in all three cases. Measures to combat these problems have been agreed to in various international frameworks: the European Community, the International North Sea Conference and the Rhine States Conference. These measures include technical emission reduction for acidifying compounds resulting in a 30% emission reduction; extension of the sewage treatment network and application of denitrification with 50% effectiveness; and introduction of measures directed at efficiency increase and emission reduction in agricultural practice in 10% of the agricultural area. The recent changes in the Common Agricultural Policy (CAP) are not expected to lead to significant changes in N flows. Assuming full implementation, an almost sufficient 45% reduction is expected for the anthropogenic nitrogen input into the North Sea. The atmospheric deposition of nitrogen compounds will be reduced by approximately 20%. The leaching of nitrates to the ground-water is expected to remain at the current level or even to increase a little. In all, these measures are conducive to solving, but do not satisfactorily solve, the three problems, mainly because the ultimate origins of the problems are not sufficiently influenced and measures therefore inevitably result in a shifting of problems.

scholarly journals Spawning location of Norway pout (Trisopterus esmarkii Nilsson) in the North Sea

2012 ◽  
Vol 69 (8) ◽  
pp. 1338-1346 ◽  
Author(s):  
Richard D. M. Nash ◽  
Peter J. Wright ◽  
Iveta Matejusova ◽  
Stefan Petev Dimitrov ◽  
Martha O'Sullivan ◽  
...  
Keyword(s):  
North Sea ◽  
Size Range ◽  
Northern Region ◽  
Stage I ◽  
The South ◽  
The North ◽  
Spawning Areas ◽  
The North Sea ◽  
Merlangius Merlangus ◽  
North Western

Abstract Nash, R. D. M., Wright, P. J., Matejusova, I., Dimitrov, S. P., O'Sullivan, M., Augley, J., and Höffle, H. 2012. Spawning location of Norway pout (Trisopterus esmarkii Nilsson) in the North Sea. – ICES Journal of Marine Science, 69: . The northern region of the North Sea (56–62°N) was sampled in February/March 2009 for eggs and in May 2010 for larvae. To aid in the identification of Norway pout stage I eggs and distinguish them from other ‘cod-like’ eggs, a Taq-Man probe was designed for this species and used here. Stage I Norway pout egg diameters collected from the field were in the range 1.03–1.28 mm and largely overlapped with the size range determined for whiting (Merlangius merlangus). The distribution of Norway pout stage I eggs in 2009 revealed the distribution of spawning in the North Sea and showed that it was similar to the distribution of 2 + Norway pout taken during the International Bottom Trawl Surveys (IBTS) over the same period covering the whole North Sea. The larvae sampled in 2010 were largely in the same area; however, larger larvae occurred to the south-east of the survey area, suggesting advection of young stages from the principal spawning areas in the north-western North Sea to the south-east and toward the Skagerrak.

scholarly journals BONN Agreement – More Than 50 Years of Spill Response Cooperation

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Johan Marius Ly ◽  
Laura de la Torre ◽  
Ronny Schallier
Keyword(s):  
North Sea ◽  
Western Europe ◽  
Oil Spills ◽  
Marine Pollution ◽  
50Th Anniversary ◽  
The European Union ◽  
Aerial Surveillance ◽  
The North ◽  
The North Sea ◽  
Bonn Agreement

Abstract In 2019, the BONN Agreement celebrated 50 years of continuous cooperation in dealing with marine pollution in Europe. This makes the Bonn Agreement the oldest regional agreement in the world established by governments for jointly dealing with and responding to pollution incidents. The first “Agreement for Cooperation in Dealing with Pollution of the North Sea by Oil” was signed in 1969 by the eight states bordering the North Sea: Belgium, Denmark, Germany, France, the Netherlands, Norway, Sweden and the United Kingdom. This was shortly after the oil tanker “Torrey Canyon” broke up off Cornwall in 1967 spilling 117 000 tonnes of oil in the first major pollution disaster affecting Western Europe. In 1983 the agreement was expanded to include “other harmful substances” as well as oil and the European Union became a Contracting Party. In 1989 the agreement was amended to include aerial surveillance. In 2010, Ireland was included and in 2019, at the 50'th anniversary, a new enlargement of the geographical scope was approved by including the Bay of Biscay through Spain's accession and a new task related to the monitoring of air pollution from ships was incorporated. The area of the Bonn Agreement now covers the Greater North Sea and its approaches, comprising most of the heavy density traffic area and oil fields in Western Europe. During these 50 years, the cooperation has resulted in a number of achievements on different topics. Some of these are: - aerial surveillance and detection of marine pollution,- harmonized pollution reporting format,- common quantification of oil spills through the Bonn Agreement Oil Appearance Code,- systems for reimbursement of costs when rendering assistance as the Bonn Agreement provides for mutual assistance between Contracting Parties,- joint exercises,- information sharing on experiences and on research & development findings,- Bonn Agreement region-wide risk assessment through the BE-AWARE project. In October 2019, the agreement's 50th anniversary was celebrated and a ministerial meeting was held. This paper will give an overview of the history, the achievements and the future for the Bonn Agreement.

scholarly journals Evidence from survey data for regional variability in cod dynamics in the North Sea and West of Scotland

2008 ◽  
Vol 65 (2) ◽  
pp. 206-215 ◽  
Author(s):  
Steven J. Holmes ◽  
Peter J. Wright ◽  
Robert J. Fryer
Keyword(s):  
Survey Data ◽  
North Sea ◽  
Gadus Morhua ◽  
Temporal Trends ◽  
Trawl Survey ◽  
Regional Variability ◽  
The North ◽  
Spawning Areas ◽  
General Decline ◽  
The North Sea

Abstract Holmes, S. J., Wright, P. J., and Fryer, R. J. 2008. Evidence from survey data for regional variability in cod dynamics in the North Sea and West of Scotland. – ICES Journal of Marine Science, 65: 206–215. Although cod (Gadus morhua) in the North Sea and ICES Division VIa are assessed as single units, recent research suggests that the stocks consist of reproductively isolated subpopulations within a metapopulation. We investigate whether temporal trends in stock indicators are asynchronous across subpopulations, which would support the metapopulation hypothesis. First quarter trawl survey data for the years 1983–2005 were aggregated into putative areas of high spawner fidelity (three in VIa, seven in the North Sea) to obtain indices of spawning–stock biomass (SSB) and recruitment (numbers-at-age 1). Asynchrony was investigated by fitting a smoother to the data for each of the ten spawning areas and testing whether the smoothers were parallel. Trends in SSB differed between spawning areas in both VIa and the North Sea. In VIa, SSB collapsed in the most southwesterly area, but remained more constant elsewhere. In the North Sea, there was a general decline in SSB, but areas thought to contain resident inshore populations showed more rapid declines than those in adjacent offshore areas. Recruitment results offered less support for a metapopulation, although recruitment in the southern North Sea declined rapidly before any trend was seen for the North Sea as a whole.

scholarly journals Small Cetacean in a Human High-Use Area: Trends in Harbor Porpoise Abundance in the North Sea Over Two Decades

2021 ◽  
Vol 7 ◽  
Author(s):  
Dominik A. Nachtsheim ◽  
Sacha Viquerat ◽  
Nadya C. Ramírez-Martínez ◽  
Bianca Unger ◽  
Ursula Siebert ◽  
...  
Keyword(s):  
North Sea ◽  
High Probability ◽  
Human Impacts ◽  
Line Transect ◽  
The European Union ◽  
Harbor Porpoise ◽  
Outer Reef ◽  
Eu Member States ◽  
The North ◽  
The North Sea

The North Sea is one of the most heavily used shelf regions worldwide with a diversity of human impacts, including shipping, pollution, fisheries, and offshore constructions. These stressors on the environment can have consequences for marine organisms, such as our study species, the harbor porpoise (Phocoena phocoena), which is regarded as a sentinel species and hence has a high conservation priority in the European Union (EU). As EU member states are obliged to monitor the population status, the present study aims to estimate trends in absolute harbor porpoise abundance in the German North Sea based on almost two decades of aerial surveys (2002–2019) using line-transect methodology. Furthermore, we were interested in trends in three Natura2000 Special Areas of Conservation (SACs), which include the harbor porpoise as designated feature. Trends were estimated for each SAC and two seasons (spring and summer) as well as the complete area of the German North Sea. For the trend analysis we applied a Bayesian framework to a series of replicated visual surveys, allowing to propagate the error structure of the original abundance estimates to the final trend estimate and designed to deal with spatio-temporal heterogeneity and other sources of uncertainty. In general, harbor porpoise abundance decreased in northern areas and increased in the south, such as in the SAC Borkum Reef Ground. A particularly strong decline with a high probability (94.9%) was detected in the core area and main reproduction site in summer, the SAC Sylt Outer Reef (−3.79% per year). The overall trend for the German North Sea revealed a decrease in harbor porpoise abundance over the whole study period (−1.79% per year) with high probability (95.1%). The assessment of these trends in abundance based on systematic monitoring should now form the basis for adaptive management, especially in the SAC Sylt Outer Reef, where the underlying causes and drivers for the large decline remain unknown and deserve further investigation, also in a regional North Sea wide context.

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