Vertical distribution and nocturnal migration of Nyctiphanes couchi (Crustacea: Euphausiacea) in relation to the summer thermocline in the Celtic Sea

1985 ◽  
Vol 89 (3) ◽  
pp. 257-262 ◽  
Author(s):  
R. Williams ◽  
N. Fragopoulu
Keyword(s):  
Vertical Distribution ◽  
Nocturnal Migration ◽  
Celtic Sea

Mesozooplankton biomass in the Celtic Sea: a first approach to comparing and combining CPR and LHPR data

1999 ◽  
Vol 79 (1) ◽  
pp. 179-181 ◽  
Author(s):  
S.D. Batten ◽  
A.G. Hirst ◽  
J. Hunter ◽  
R.S. Lampitt
Keyword(s):  
High Resolution ◽  
Vertical Distribution ◽  
Zooplankton Biomass ◽  
Data Sets ◽  
Shelf Edge ◽  
Mesozooplankton Biomass ◽  
Celtic Sea ◽  
First Time ◽  
Vertical Scales ◽  
The Vertical Distribution

Zooplankton biomass varies on temporal, horizontal and vertical scales. However, data sets which incorporate all these dimensions at high resolution are very rare. Two devices which measure all these aspects have recently been simultaneously deployed in the Celtic Sea, the continuous plankton recorder (CPR) and the Longhurst–Hardy plankton recorder (LHPR). This demonstrates that integrated biomass derived from the LHPR are not significantly different from those derived using the CPR. Values have, therefore, been combined for the first time to describe the vertical distribution of mesozooplankton biomass at the Celtic Sea shelf edge through an annual cycle. This suggests that the surface biomass peak is broader at the shelf break than in the open ocean and in the autumn the main biomass peak may be below the depth sampled by the CPR.

Observations on the Vertical Distribution of Eggs and Larvae of Mackerel and other Teleosts in the Celtic Sea and on the Sampling Performance of Different Nets in Relation to Stock Evaluation

1980 ◽  
Vol 60 (2) ◽  
pp. 295-311 ◽  
Author(s):  
A. J. Southward ◽  
B. McK. BARY
Keyword(s):  
Vertical Distribution ◽  
Geographical Pattern ◽  
Spawning Grounds ◽  
The Past ◽  
South West ◽  
Complete Survey ◽  
Celtic Sea ◽  
The Vertical Distribution ◽  
Eggs And Larvae ◽  
Made In

There is some controversy about the strength of the stock of mackerel in the Celtic Sea and off the coasts of Cornwall and Ireland, and it is difficult to find out if the numbers of mackerel in this area have fluctuated in the past (Johnson, 1977; Lockwood & Johnson, 1976; Lockwood, 1978; Coombs, Pipe & Mitchell, 1977,1979, 1980). The earliest complete survey of the south-west spawning grounds was made in 1937–9 (Steven & Corbin, 1939; Corbin, 1947) and was principally designed to show the seasonal and geographical pattern, not provide a basis for stock evaluation. Nevertheless, this survey is the only information we have about the breeding of mackerel in the days before the war when fishing was performed with drift-nets and lines, a period when we can assume exploitation was very much less intense than today when trawls and purse-seines are used. Attempts to use the 1937–9 data for estimation of the pre-war stock have been regarded as giving unsatisfactory results (Walsh, 1976). The data from the 1937–9 surveys were defective because we did not know the influence of the depth of fishing of the nets in relation to the vertical distribution of the eggs, nor the efficiency and catching capacity of the nets for sampling eggs and post-larvae.

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