scholarly journals Observations on herring spawning and larval distribution in the Firth of Clyde in 1958

1959 ◽  
Vol 38 (3) ◽  
pp. 445-453 ◽  
Author(s):  
B. B. Parrish ◽  
A. Saville ◽  
R. E. Craig ◽  
I. G. Baxter ◽  
R. Priestley
Keyword(s):  
North Sea ◽  
Predatory Fish ◽  
Hatching Rate ◽  
Atlantic Herring ◽  
The North ◽  
Larval Distribution ◽  
Sea Bed ◽  
The North Sea ◽  
Newly Hatched Larvae ◽  
The Relationship

Apart from the extensive egg surveys carried out by Norwegian workers (Runnstrom, 1941) most of the investigations on the spawning of the Atlantic Herring have depended on studies of the distribution of the spawning fish, on captures of newly hatched larvae, and on records of the occurrence of herring eggs in the stomachs of predatory fish species (principally haddock). With the exception of recent observations by Bolster and Bridger (1957), attempts to sample egg concentrations quantitatively in the North Sea and neighbouring areas have usually proved abortive. In consequence little is known of the distribution and density of eggs on the spawning grounds, their percentage fertilization, mortality during the egg stage, hatching rate, and the relationship between the distribution of eggs and the nature of the sea-bed.

The Thirty-Ninth Thomas Lowe Gray Lecture: Offshore Drilling, with Particular Reference to the North Sea and the ‘Sea Quest’

1966 ◽  
Vol 181 (1) ◽  
pp. 848-875 ◽  
Author(s):  
R. G. S. Avery
Keyword(s):  
North Sea ◽  
Essential Factor ◽  
Safety Equipment ◽  
Offshore Drilling ◽  
Advantages And Disadvantages ◽  
The North ◽  
Drilling Equipment ◽  
Sea Bed ◽  
Weight Problems ◽  
The North Sea

The origins of offshore drilling work and the development of structures used at sea are traced. Comparison of the various types illustrates the advantages and disadvantages of each. Tables show the numbers in operation, being built, and the apparent liability of each type to damage. Typical bore-hole structures are illustrated, the need for undersea well-heads explained and their development into a sea-bed completion is discussed. Much more research is necessary before this can be considered a practical proposition. The design of drilling barge equipment is compared with typical land rigs and the development of drilling equipment, including the sophisticated electric drive and turbo-drill, discussed. Rigs in various types of barge are compared. Fire precautions and other safety equipment are described. The problems associated with control by the driller lead to complications of motive power layout. The lecture describes in some detail the design of the semi-submersible drilling barge Sea Quest, illustrates the weight problems and their effect on floating stability and indicates the need for management decisions on the degree of resistance to damage. This is measured by the variable deck load of drilling equipment that can be held on board and the degree of weather deterioration that can be tolerated before disengaging the drill from the hole. The need for, and extent of, diving is discussed, with some comparison between diving vehicles. Weather too is an essential factor of work in the North Sea and both pre-surveys and day-to-day reporting are described.

scholarly journals Reconstruction of Atlantic herring ( Clupea harengus ) recruitment in the North Sea for the past 455 years based on the δ 13 C from annual shell increments of the ocean quahog ( Arctica islandica )

2019 ◽  
Vol 20 (3) ◽  
pp. 537-551 ◽  
Author(s):  
Juan Estrella‐Martínez ◽  
Bernd R. Schöne ◽  
Ruth H. Thurstan ◽  
Elisa Capuzzo ◽  
James D. Scourse ◽  
...  
Keyword(s):  
North Sea ◽  
Clupea Harengus ◽  
Atlantic Herring ◽  
Arctica Islandica ◽  
The Past ◽  
The North ◽  
The North Sea

Sole larval distribution (Solea solea) in the eastern English Channel and Southern Bight of the North Sea

2001 ◽  
Vol 81 (4) ◽  
pp. 673-678 ◽  
Author(s):  
A. Grioche ◽  
P. Koubbi ◽  
X. Harlay ◽  
B. Sautour
Keyword(s):  
North Sea ◽  
Environmental Parameters ◽  
English Channel ◽  
Southern Bight ◽  
Intermediate Variable ◽  
Larval Stages ◽  
The North ◽  
Larval Distribution ◽  
Solea Solea ◽  
The North Sea

The distribution of sole (Solea solea) eggs and larvae were described from two cruises conducted in April and May 1995 along the French coast of the eastern English Channel and the Belgian coast of the Southern Bight of the North Sea. Sole migration was investigated using larval stages and univariate spatial analysis as geostatistics (variograms). Important environmental parameters were selected by comparison with larval distribution. Path analysis was used to remove spatial correlation and to define links between abundance and environmental variables.  Sole larvae were found to be coastal throughout their development. Strong links between larval distribution and environmental parameters were identified, particularly for the younger stages which were found in higher abundance in areas of high chlorophyll-a concentration. The association was not direct, suggesting that the larval spatial distribution was influenced by an undetermined, intermediate variable, such as larval prey. Sole larvae are retained in the coastal area throughout ontogeny despite the strong hydrodynamics which characterize the region. Larval distribution resulted from behavioural mechanisms as well as environmental influences.

A series of North Sea benthos surveys with trawl and headline camera

1982 ◽  
Vol 62 (2) ◽  
pp. 297-313 ◽  
Author(s):  
M. F. Dyer ◽  
W. G. Fry ◽  
P. D. Fry ◽  
G. J. Cranmer
Keyword(s):  
North Sea ◽  
Local Population ◽  
Demersal Fish ◽  
Population Densities ◽  
The North ◽  
Sea Bed ◽  
Successful Series ◽  
The North Sea

During a series of North Sea demersal fish surveys, a headline camera was used to photograph the sea-bed at intervals of 1 min, throughout the duration of 60 min trawls. A successful series of underwater photographs were obtained at 119 stations throughout the North Sea. In addition, the benthos caught at 317 stations was recorded.A total of ca. 30 species could be identified on the underwater photographs, and of these ten species were sufficiently common or locally abundant for estimates of local population densities to be made. Distributions throughout the North Sea based on specimens trawled and specimens photographed were compared.

The Orography of the North Sea Bed

1935 ◽  
Vol 86 (4) ◽  
pp. 334 ◽  
Author(s):  
R. G. Lewis
Keyword(s):  
North Sea ◽  
The North ◽  
Sea Bed ◽  
The North Sea

scholarly journals Noctiluca scintillans: Dynamics, Size Measurements and Relationships With Small Soft-Bodied Plankton in the Belgian Part of the North Sea

2021 ◽  
Vol 8 ◽  
Author(s):  
Anouk Ollevier ◽  
Jonas Mortelmans ◽  
Anaïs Aubert ◽  
Klaas Deneudt ◽  
Michiel B. Vandegehuchte
Keyword(s):  
North Sea ◽  
Temporal Dynamics ◽  
Negative Impact ◽  
Large Cell ◽  
Nutrient Inputs ◽  
Anthropogenic Pressures ◽  
Noctiluca Scintillans ◽  
The North ◽  
The North Sea ◽  
The Relationship

Climate driven changes and anthropogenic pressures on the marine environment have been shown to favor the increase in certain potentially harmful species. Among them, Noctiluca scintillans, a common dinoflagellate, often blooms during warm summers and is known to affect plankton communities. In this study, we assessed the dynamics in abundance and cell size of N. scintillans as well as the relationship between N. scintillans and small soft-bodied zooplankton in the Belgian part of the North Sea (BPNS), since negative correlations between these plankton groups have been previously reported for nearby regions. This study is the first to present consistently counted N. scintillans cell numbers and measured cell lengths, through the analysis of ZooScan images from samples taken monthly at stations throughout the coastal zone of the BPNS. The results show that N. scintillans demonstrated clear seasonal dynamics with both high densities and large cell sizes in spring/summer (May-July). The occurrence of N. scintillans in the analyzed plankton samples and the abundance of N. scintillans at the observed peak intensities nearly tripled over a period of 5 years. A zero-inflated model showed a correlation of N. scintillans abundance with temperature as well as with phosphate concentrations, suggesting that anthropogenic influences such as climate change and riverine nutrient inputs could affect the temporal dynamics of the species. The results, on the other hand, did not show any negative impact of N. scintillans on the soft-bodied plankton community.

Shetland beached bird surveys: national and European context

1995 ◽  
Vol 103 ◽  
pp. 165-179 ◽  
Author(s):  
M. Heubeck
Keyword(s):  
North Sea ◽  
Annual Variation ◽  
Herring Gull ◽  
British Isles ◽  
European Context ◽  
The North ◽  
Bird Survey ◽  
The North Sea ◽  
The Relationship

SynopsisA Shetland-wide beached bird survey was established in March 1979 and monthly surveys have continued since. This paper presents results from March 1979 to December 1992 during which time a total of 34 320 corpses of seabird and seaduck were found, of which 34023 (99.1%) were specifically identified. Corpses of guillemot (8911), fulmar (8707), kittiwake (4421), herring gull (2264), shag (1843) and great black-backed gull (1785) comprised 82.1% of the identified total, the remainder being made up of 31 other species. The relationship between the numbers of each species found, and their numbers and occurrence in Shetland waters is discussed. A total of 2781 corpses were judged to have been oiled before their deaths, of which 2732 (98.2%) were specifically identified. The six species most frequently found oiled were guillemot (1170 corpses), fulmar (543), kittiwake (184), razorbill (131), puffin (111) and shag (99).Variations in both the percentage of corpses found that were oiled, and the number of oiled corpses found per kilometre of beach surveyed, are examined and discussed. Comparison is made with results from beached bird surveys elsewhere in the British Isles and in other countries bordering the North Sea. In some species, notably the pelagic auks, there was considerable annual variation in the numbers of unoiled corpses found while in other species the number of unoiled corpses found changed more gradually over the 14 years. Reference is made to similar changes observed in other beached bird surveys and possible reasons for these changes are discussed.

Doggerland: a Speculative Survey

1998 ◽  
Vol 64 ◽  
pp. 45-81 ◽  
Author(s):  
B.J. Coles
Keyword(s):  
North Sea ◽  
Human Occupation ◽  
River Systems ◽  
The North ◽  
Geological Surveys ◽  
Geological Processes ◽  
Sea Bed ◽  
The North Sea

Archaeologists tend to refer to the land that once existed between Britain and the continent as a landbridge. It was, however, a landscape as habitable as neighbouring regions, and here called Doggerland to emphasise its availability for settlement by prehistoric peoples. Evidence from the Geological Surveys undertaken by countries bordering the North Sea Basin, together with allied research, is drawn together to provide an overview of the possibilities. A range of interacting geological processes implies that the present-day relief of the North Sea bed does not provide a sound guide to the relief of the former landscape, nor to the chronology and character of its submergence. A series of maps accompanies the text to provide a speculative reconstruction of the topography, river systems, coastline, vegetation, fauna, and human occupation of Doggerland from the Devensian/Weichselian maximum to the beginnings of the Neolithic.

scholarly journals Realized habitats of early-stage North Sea herring: looking for signals of environmental change

2010 ◽  
Vol 68 (3) ◽  
pp. 537-546 ◽  
Author(s):  
Christine Röckmann ◽  
Mark Dickey-Collas ◽  
Mark R. Payne ◽  
Ralf van Hal
Keyword(s):  
Time Series ◽  
Environmental Change ◽  
North Sea ◽  
Early Stage ◽  
Interannual Variations ◽  
The Past ◽  
The North ◽  
The North Sea ◽  
Juvenile Stages ◽  
Newly Hatched Larvae

Abstract Röckmann, C., Dickey-Collas, M., Payne, M. R., and van Hal, R. 2011. Realized habitats of early-stage North Sea herring: looking for signals of environmental change. – ICES Journal of Marine Science, 68: . Realized habitats of North Sea herring for two larval and two juvenile stages were estimated over the past 30 years, using abundances from surveys tied to modelled estimates of temperature and salinity. Newly hatched larvae (NHL) were found mainly in water masses of 9–11°C, pre-metamorphosis larvae (PML) around 5–6°C, juveniles aged 0 in summer around 13–14°C, and juveniles aged 1 in winter around 4–5°C. The median salinity in which the NHL were distributed was 34.4–35.0 and 33.7–33.9, respectively, for PML and juveniles. Interannual variations in temperature and geographic variables in the North Sea were compared with the time-series of realized habitats. The realized temperature habitats of the NHL did not change over time, but the habitat of juveniles in summer may be associated with higher temperatures. Juveniles aged 1 in winter are found in waters colder than the average for the North Sea, a result also reflected in their geographic shift east into shallower water. The results suggest that juveniles could be limited by temperature, but may also track changes in food or predator distribution, and/or internal population dynamics. Time-series analysis of realized salinity habitats was not possible with the available data because of differences between model outputs.

Sign in / Sign up

Export Citation Format

Share Document