scholarly journals Estimation of saithe Pollachius virens growth rates around the Beryl oil platforms in the North Sea: a comparison of methods

1992 ◽  
Vol 86 ◽  
pp. 31-40 ◽  
Author(s):  
EM Mathers ◽  
DF Houlihan ◽  
MJ Cunningham
Keyword(s):  
North Sea ◽  
Growth Rates ◽  
Comparison Of Methods ◽  
Oil Platforms ◽  
The North ◽  
The North Sea

scholarly journals Modeled larval fish prey fields and growth rates help predict recruitment success of cod and anchovy in the North Sea

2018 ◽  
Vol 600 ◽  
pp. 111-126 ◽  
Author(s):  
KB Huebert ◽  
J Pätsch ◽  
M Hufnagl ◽  
M Kreus ◽  
MA Peck
Keyword(s):  
North Sea ◽  
Growth Rates ◽  
Larval Fish ◽  
Fish Prey ◽  
Recruitment Success ◽  
The North ◽  
The North Sea

Long-term variability in North Sea zooplankton off the Northumberland coast: productivity of small copepods and analysis of trophic interactions

1988 ◽  
Vol 68 (1) ◽  
pp. 143-164 ◽  
Author(s):  
John C. Roff ◽  
Ken Middlebrook ◽  
Frank Evans
Keyword(s):  
North Sea ◽  
Trophic Interactions ◽  
Growth Rates ◽  
Larval Fish ◽  
The North ◽  
The North Sea ◽  
The Mean ◽  
June July

All groups of meso- and macro-zooplankton in the North Sea off Northumberland, at a depth of 53 m, were studied during a 15-year period (1969–83); copepod productivity was estimated from biomass and growth rates. Phytoplankton were seasonally bi-modal with peaks in April and August–October; copepods were uni-modal peaking in June–July. The predatory zooplankters: larval fish, decapods, ctenophores, medusae (the summer-autumn predators) peaked between May and September, while chaetognaths and euphausiids (the winter predators) peaked in December–January. Copepods and the summer-autumn predators were seasonally and inter-annually positively correlated, and declined in abundance from 1974 to 1980. Euphausiids and chaetognaths on the contrary increased in abundance during these years, and were seasonally and inter-annually negatively correlated to the copepods. The mean annual abundance of copepods was positively related to the previous winter's minimum, and inversely related to the abundance of chaetognaths and euphausiids. Annual copepod productivity averaged 1260 kJ m-2 year-1, and showed no relationship to other groups of plankton.

Future increase in harmful algal blooms in the North Sea due to climate change

2005 ◽  
Vol 51 (5) ◽  
pp. 31-36 ◽  
Author(s):  
L. Peperzak
Keyword(s):  
Climate Change ◽  
North Sea ◽  
Growth Rates ◽  
Ecosystem Functioning ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Cost Benefit ◽  
The North ◽  
Marine Food Chain ◽  
The North Sea

In temperate seas such as the North Sea harmful (toxic) algal blooms will probably increase as a result of climate change. This conclusion was reached after investigating the projected effect of climate change for the year 2100 in Dutch coastal waters (4°C temperature rise and increased water column stratification) on the growth rates of six harmful and two non-harmful phytoplankton species. Micro algae form the basis of the marine food chain. However, toxin-producing species may seriously disrupt the food web and lead to fish kills and human intoxication. Two species with estimated doubled growth rates in 2100, F. japonica and C. antiqua, entered Europe via ship's ballast water or shellfish imports. This stresses the need to legally regulate such invasion routes in order to prevent the import of novel species. Future toxic phytoplankton blooms may further devaluate ecosystem deliverables such as fish production or recreational use. This devaluation can be estimated by monetary value assessments that are needed in cost-benefit analyses for policy guidance. The lack of understanding of future climate, ecosystem functioning and its response to climate change calls for a scientific effort to improve our knowledge on present day coastal ecosystem functioning and its resilience.

Validation of EGNOS Helicopter Approach Procedures to North Sea Oil Platforms

2009 ◽  
Vol 62 (2) ◽  
pp. 189-201 ◽  
Author(s):  
J. Valner ◽  
S. J. Leighton
Keyword(s):  
Feasibility Study ◽  
North Sea ◽  
Royal Institute ◽  
Fatal Accidents ◽  
Oil Platforms ◽  
The North ◽  
The North Sea

A version of this paper was first presented at the Royal Institute of Navigation NAV 08 Conference held at Church House, Westminster, London in October 2008.The North Sea oil platforms are reliant on regular and reliable helicopter operations for the movement of staff and supplies. The environment is challenging and there have been six fatal accidents incurring the loss of 79 lives since the mid-1970s. The need for accurate and reliable helicopter approach procedures has been identified and this paper reports the results of a feasibility study into the use of EGNOS-based approaches to oil platforms in the North Sea.

Geographical differences in growth rates of Arctica islandica (Mollusca: Bivalvia) from the North Sea and adjacent waters

1999 ◽  
Vol 79 (5) ◽  
pp. 907-915 ◽  
Author(s):  
R. Witbaard ◽  
G.C.A. Duineveld ◽  
P.A.W.J. de Wilde
Keyword(s):  
Growth Rate ◽  
Primary Production ◽  
North Sea ◽  
Growth Rates ◽  
Shell Growth ◽  
Geographical Differences ◽  
Arctica Islandica ◽  
The North ◽  
Standard Coefficient ◽  
The North Sea

Geographical differences in the shell growth rate of several populations of the bivalve Arctica islandica (Mollusca: Bivalvia) were estimated by using the growth lines laid down during their first ten years of life. Attention was focused on populations from the North Sea, but for comparison small samples from adjacent waters were also analysed. A four-fold difference in the average growth rate was found between the slowest and fastest growing shells.Principal component analysis was used to summarize the inter-relationships between environmental variables and growth rates. Shell growth correlated positively with primary production and temperature and inversely with depth and the silt content of the sediment. The North Sea specimens were found to have a strong positive correlation with grain size. Since sediment characteristics also depend on bottom currents, it is suggested that these increased rates reflect lateral seston flux as additional food supply.In a multiple regression model, applied to all available data, average annual temperature, primary production and the interaction between production and water depth explained 50% of the variance. The derived standard coefficients for temperature, primary production and the interaction between depth and primary production were 0.90, 0.47 and −0.92 respectively. The results of this study suggest that the temperature effects on in situ shell growth are easily overruled by other environmental factors.If a similar model was calculated with North Sea data only, 75% of the variance was explained by temperature, primary production and depth×primary production. The standard coefficient for primary production was 1.26. The role of temperature in explaining the observed growth differences is negligible since the standard coefficient is −0.098. The interaction term, depth×primary production had a standard coefficient of −0.95.

Settlement processes induce differences in daily growth rates between two co-existing ecotypes of juvenile cod Gadus morhua

2020 ◽  
Vol 650 ◽  
pp. 175-189 ◽  
Author(s):  
KEM Jørgensen ◽  
AB Neuheimer ◽  
PE Jorde ◽  
H Knutsen ◽  
P Grønkjær
Keyword(s):  
North Sea ◽  
Growth Rates ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Life Stage ◽  
Fish Length ◽  
Daily Growth ◽  
The North ◽  
Significant Difference ◽  
The North Sea

Co-existence of sympatric populations of a fish species is a common phenomenon. In the fjords of southern Norway, 2 ecotypes of Atlantic cod Gadus morhua co-exist during their juvenile life stage. Cod of the North Sea ecotype are on average 2 cm larger than the fjord ecotype at the end of their first growing season in October, suggesting either differences in spawning time or differences in growth during the larval and early juvenile phase. We analysed 24352 daily otolith increments from 145 cod sampled in September 2000, 2003, 2008 and 2015 at 2 locations to estimate individual hatching times and daily growth rates. There was no significant difference in hatching time between ecotypes, locations or years. Population-specific models of the effect of year, temperature and fish length on growth rates showed that the North Sea ecotype grew significantly faster than the fjord ecotype, but growth rate differences were small until the juveniles reached ~40 mm and disappeared again in juveniles larger than 110 mm. The size range (40-110 mm) corresponds to the period following settling. This study documents how vital rates (e.g. growth rates) may change rapidly at ontogenetic transition points, leading to different phenotypic trajectories in co-existing ecotypes. It also highlights the importance of settlement as a key life-history transition that may amplify small existing differences in growth rates through positive feedback of size on competitive ability and eventually recruitment.

Growth changes in plaice, cod, haddock and saithe in the North Sea: a comparison of (post-)medieval and present-day growth rates based on otolith measurements

2004 ◽  
Vol 51 (3-4) ◽  
pp. 313-328 ◽  
Author(s):  
Loes J Bolle ◽  
Adriaan D Rijnsdorp ◽  
Wim van Neer ◽  
Richard S Millner ◽  
Piet I van Leeuwen ◽  
...  
Keyword(s):  
North Sea ◽  
Growth Rates ◽  
The North ◽  
The North Sea ◽  
Growth Changes
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