scholarly journals Growth rate of Iceland and North Sea blue whiting, Micromesistius poutassou (Risso,1810), back-calculated from otoliths

1978 ◽  
Vol 08 (2) ◽  
pp. 5-22 ◽  
Author(s):  
Andrzej Kompowski
Keyword(s):  
Growth Rate ◽  
North Sea ◽  
Blue Whiting

scholarly journals Haddock on the Porcupine Bank, September 1944

1946 ◽  
Vol 26 (3) ◽  
pp. 398-407 ◽  
Author(s):  
C. F. Hickling
Keyword(s):  
Growth Rate ◽  
North Sea ◽  
Growing Up ◽  
Fishing Mortality ◽  
Rate Of Growth ◽  
The North ◽  
The North Sea

1. It is suggested that the population of haddock (Gadus aeglefinus L.) on the Porcupine Bank is largely a self-contained stock.2. This stock had complete immunity from trawling from December 1940, to September 1944.3. In 1939 and 1940 there was an abundance of small haddock in this stock, due to the good brood of 1938. In 1944, this brood was still very abundant, and was then joined by the good brood of 1942.4. These two good broods, growing up immune from fishing mortality, caused the Porcupine Bank to carry, in 1944, the densest stock of haddock ever experienced there.5. The average number of sclerites in the first zone of the scales of these fish is the highest recorded in any region. It is still high in the second zone, but in the later zones falls below that found in the scales of haddock from other regions.6. The growth rate was faster, in the first four years of life, than even that of Iceland and Faroe haddock, but in the later years it fell behind these, though still superior to the growth rate of the North Sea haddock.7. The expectation that this greatly increased stock of haddock, due to the war-time cessation of fishing, would show a slowing in its rate of growth, due to intensified competition for the available food, is not supported by the facts.

Assessment of growth rate limiting nutrients in the north sea by the use of nutrient-uptake kinetics

1990 ◽  
Vol 26 (1) ◽  
pp. 53-60 ◽  
Author(s):  
R. Riegman ◽  
F. Colijn ◽  
J.F.P. Malschaert ◽  
H.T. Kloosterhuis ◽  
G.C. Cadée
Keyword(s):  
Growth Rate ◽  
Nutrient Uptake ◽  
North Sea ◽  
Uptake Kinetics ◽  
The North ◽  
Limiting Nutrients ◽  
The North Sea ◽  
Rate Limiting ◽  
Nutrient Uptake Kinetics

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.

Recent occurrences of blue whiting, Micromesistius poutassou, and Norway pout, Trisopterus esmarkii, in the English Channel and southern North Sea

1981 ◽  
Vol 61 (2) ◽  
pp. 307-313 ◽  
Author(s):  
R. W. Blacker
Keyword(s):  
North Sea ◽  
Bay Of Biscay ◽  
English Channel ◽  
Blue Whiting ◽  
Southern North Sea ◽  
Large Numbers ◽  
Celtic Sea

Large numbers of Micromesistius poutassou were caught in the English Channel during the spring of 1979. Later in 1979 and in the early months of 1980 smaller numbers were recorded from the southern North Sea where this species has rarely been recorded before. The M. poutassou were accompanied by small numbers of T. esmarkii in the eastern English Channel but no T. esmarkii were found in the southern North Sea. T. esmarkii were taken off Plymouth on two occasions in 1977 and more regularly since 1979. M. poutassou has been recorded there sporadically since 1957. Both species were caught in considerable numbers around the Scillies in 1977 and 1978. The invasion of the English Channel by M. poutassou in 1979 may have come from the Bay of Biscay rather than the Celtic Sea, but the appearance of T. esmarkii in the Plymouth area since 1977 may be a result of changes in the ecosystem since 1964.

Relationship between Juvenile Growth and the Onset of Sexual Maturity of Female North Sea Plaice, Pleuronectes platessa

1993 ◽  
Vol 50 (8) ◽  
pp. 1617-1631 ◽  
Author(s):  
A. D. Rijnsdorp
Keyword(s):  
Growth Rate ◽  
North Sea ◽  
Population Analysis ◽  
Age Groups ◽  
Population Level ◽  
Individual Growth ◽  
Juvenile Growth ◽  
Pleuronectes Platessa ◽  
Mature Fish ◽  
The Individual

The relationship between juvenile growth and the onset of sexual maturation of female North Sea plaice, Pleuronectes platessa, is explored on the individual and population level by analysing individual growth curves back-calculated from otoliths of immature and mature fish and by analysing maturity–length ogives of individual cohorts sampled between 1960 and 1990 from commercial landings from three areas in the North Sea. Back-calculated growth rate of females sampled as mature fish was higher than that of immature females up to 3 yr prior to sampling but lower in the last year. The probability of maturation was significantly related to the length reached as well as to the growth rate in previous years. Maturity–length relationships from market samples showed significant differences in slopes and intercepts between age groups, geographical areas, and year classes. Length at maturation (Lmat) decreased with age and increased with latitude. The differences in Lmat of individual year-classes corresponded to differences in the growth rate and temperature during early life. Both the evidence obtained from the individual and population analysis suggest a 2- to 3-yr maturation time. A model of the juvenile–adult transition process is proposed that provides a consistent interpretation of the observations.

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