Studies on a Calanus Patch III. The quantity of food eaten by Calanus finmarchicus

The purpose of this paper is to assess the grazing capacity of Calanus finmar-chicus (Gunner.) in terms of the quantity of food eaten in the sea. The part played in the growth of the animal by the quantity eaten will only be briefly discussed. The parts played by nutrient lack, sinking and diffusion on the algal productive rates will also be discussed, leading to the conclusion that grazing mortality is the most effective controlling agent on algal production.A subsidiary purpose of this paper is to relate changes in the weight of Calanus finmarchicus to changes in food consumed and to changes in water temperature. Measurements of C. finmarchicus have been made by a number of workers (Adler & Jespersen, 1920; Russell, 1928; Marshall, 1933; Stormer, 1929; Bogorov, 1934; Jespersen, 1939; Clarke & Zinn, 1937). It will be shown that in the North Sea, in spring, the greatest changes in weight are most readily related to changes in quantities of food consumed.

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Seasonal variations in the occurrence of Vibriovulnificusalong the Dutch coast

Epidemiology and Infection ◽

10.1017/s0950268800057691 ◽

1994 ◽

Vol 112 (2) ◽

pp. 285-290 ◽

Cited By ~ 23

Author(s):

J. Veenstra ◽

P. J. G. M. Rietra ◽

J. M. Coster ◽

E. Slaats ◽

S. Dirks-Go

Keyword(s):

Seasonal Variation ◽

Water Temperature ◽

North Sea ◽

Seasonal Variations ◽

Water Samples ◽

Human Disease ◽

Sea Water ◽

Dutch Coast ◽

The North ◽

The North Sea

SUMMARYThe seasonal variation in the occurrence ofV. vulnificusin relation to water temperature and salinity was studied along the Dutch coast. In two consecutive yearsV. vulnificusstrains could be isolated in August when the water temperature was highest. The indole-positive strains isolated from North Sea water samples were identical to most strains isolated from human disease and from the environment. However, strains isolated from four of five patients living in countries around the North Sea were different from the North Sea isolates in that they were indole-negative and have a lower NaCl tolerance.

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Composition and origin of milky water in the North Sea

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s002531540004042x ◽

1980 ◽

Vol 60 (3) ◽

pp. 759-768 ◽

Cited By ~ 34

Author(s):

J. K. Volkman ◽

R. R. Gatten ◽

J. R. Sargent

Keyword(s):

North Sea ◽

Mass Spectra ◽

Oxidative Degradation ◽

Wax Esters ◽

Calanus Finmarchicus ◽

Wax Ester ◽

Capillary Gc ◽

The North ◽

The North Sea ◽

Calanus Species

An occurrence of ‘milky water’ which covered a wide area of the North Sea in June 1975 is described. The water contained 20 mg/1 of an oil which was shown by capillary GC-MS to consist mainly (> 80%) of two wax esters 34:1 and 36:1. Analysis of the acids and alcohols released by hydrolysis, and interpretation of the wax ester mass spectra, indicated that the 34:1 ester was almost entirely composed of the alcohol-acid combination 20:1–14:0 and the 36:1 ester was composed of 22:1–14:0 (75%) and 20:1–16:0 (19%). Wax esters of virtually the same composition predominate in the lipids of the copepod Calanus finmarchicus which has the implication that the ‘milky water’ was caused by ageing of the oil released following a mass mortality of copepods. The lack of polyunsaturated wax esters and of astaxanthin is ascribed to oxidative degradation of these labile lipids following release into the sea. A copepod origin for the milky water is further supported by its containing small amounts of cholesterol and pristane, both of which are common to Calanus species.

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Seasonal dynamics of phytoplankton and Calanus finmarchicus in the North Sea as revealed by a coupled one-dimensional model

Limnology and Oceanography ◽

10.4319/lo.1996.41.3.0522 ◽

1996 ◽

Vol 41 (3) ◽

pp. 522-539 ◽

Cited By ~ 58

Author(s):

François Carlotti ◽

Günther Radach

Keyword(s):

North Sea ◽

Seasonal Dynamics ◽

Calanus Finmarchicus ◽

Dimensional Model ◽

One Dimensional ◽

The North ◽

The North Sea

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Does copepod size determine food consumption of particulate feeding fish?

ICES Journal of Marine Science ◽

10.1093/icesjms/fst090 ◽

2013 ◽

Vol 71 (1) ◽

pp. 35-43 ◽

Cited By ~ 15

Author(s):

Mikael van Deurs ◽

Marja Koski ◽

Anna Rindorf

Keyword(s):

Food Consumption ◽

North Sea ◽

Fish Larvae ◽

Handling Time ◽

Growth Conditions ◽

Calanus Finmarchicus ◽

Fish Feeding ◽

The North ◽

The North Sea ◽

Particulate Feeding

Abstract van Deurs, M., Koski, M., and Rindorf, A. Does copepod size determine food consumption of particulate feeding fish? – ICES Journal of Marine Science, 71: . The climate-induced reduction in the mean copepod size, mainly driven by a decrease in the abundance of the large Calanus finmarchicus around 1987, has been linked to the low survival of fish larvae in the North Sea. However, to what extent this sort of reduction in copepod size has any influence on adult particulate feeding fish is unknown. In the present study, we investigated the hypothesis that the availability of the large copepods determines food consumption and growth conditions of lesser sandeel (Ammodytes marinus) in the North Sea. Analysis of stomach content suggested that food consumption is higher for fish feeding on large copepods, and additional calculations revealed how handling time limitation may provide part of the explanation for this relationship. Comparing stomach data and zooplankton samples indicated that lesser sandeel actively target large copepods when these are available. Finally, we observed that the length of lesser sandeel began to decrease in the late 1980s, simultaneously with the C. finmarchicus decline.

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