1976 - 1976 Centre for Environment, Fisheries & Aquaculture Science (Cefas) West Central North Sea Plankton Survey - RV Corella 08/76
<span style="font-family: 'Trebuchet MS','sans-serif'; color: black;">...</span>
dataset
http://data.cefas.co.uk/#/View/2522/
function: order
CEFASa5fa8551-e683-4bed-86eb-28351e14f7a9
http://www.cefas.co.uk/
eng
OGP
urn:ogc:def:crs:EPSG::4326
biota
revision
2011-03-25
publication
2008-06-01
publication
2008-06-01
-2
4
56.5
52.5
revision
2010-05-18
1976-05-27
1976-06-07
publication
2016-07-14
notPlanned
Sample collection: A grid of stations were worked based on the ICES statistical rectangles over the area from north Norfolk to 56̊N and to longitude 2̊E. Sampling points were 18 nautical miles apart longitudinally and along latitude lines 15 nautical miles apart. In the centre of this grid, to the north of the River Humber and to the south of the River Tyne, intermediate sampling points 9 nautical miles apart were designated; this central part constituted the main priority plankton sampling grid. This survey grid was worked on twelve cruises between the end of January and the beginning of November. Seven cruises were planned for the first four months to sample cod and plaice spawnings, while the remainder, at approximately monthly intervals, were to sample summer- and autumn-spawning fish. The sampling gear used for the main surveys was the Lowestoft multipurpose plankton sampler. This sampler consists of a 30 inch (76 cm) diameter fibreglass tube enclosing a conical nylon filtering net, 185 cm long. The mesh of the net has an aperture of 270 µm and a porosity of 46%. Water enters the net via a hemispherical nose cone with an opening of 16 inches (40.6 cm) diameter giving a 7: 1 ratio of open area of net to sampler mouth opening. The main sampler net was used to collect fish eggs and larvae and other macroplankton (particle size > 300 µm) including edible crab larvae. Two accessory samplers were mounted on the body of the main sampler, each one made up of a 6 inch (15 cm) diameter PVC tube with a metal nose cone with a 2 inch (5.1 cm) aperture. Each accessory sampler contained a conical nylon filtering net, 147 cm long, of mesh aperture 35 µm and porosity 16% in one sampler, and 61 µm and 26% respectively in the other. These accessory samplers were used to collect the smaller zooplankton and large diatoms and dinoflagellates. An electromechanical flowmeter was fitted in the nose cone of the main sampler and standard mechanical flowmeters at the rear of each accessory sampler. An additional mechanical flowmeter was mounted on the outside of the main sampler, operating continuously in free stream. The sampler was operated over the stern of the vessel at a towing speed of *5* knots. A Scripps depressor on a 30 cm strop was attached to the underside of the sampler immediately behind the nose cone. By paying out and hauling the cable at a constant speed, the sampler performed a shallow, oblique dive to within 2 m of the sea bed and back to the surface, thus providing an equivalent sample of each part of the water column. The samples collected at sea by the main net and by the two auxillary samplers were each washed carefully from the net into the collecting bag on the end of the net. The sample was then transferred to a glass storage jar, labelled and fixed by the addition of 40% sodium acetate buffered formalin, in the ratio one part fixative to nine parts sample plus seawater. Sample analysis: Whenever practicable, the whole main net sample was sorted for fish eggs and larvae. Sub-sampling was limited to those samples containing exceptionally large numbers of eggs or larvae.
Public data (Crown Copyright) - Open Government Licence Terms and Conditions apply
Public data (Crown Copyright) - Open Government Licence Terms and Conditions apply
Data Manager
Centre for Environment, Fisheries & Aquaculture Science
Cefas Lowestoft Laboratory
Pakefield Road
Lowestoft
NR33 0HT
UK
+44 (0)1502 562244
originator
Data Manager
Centre for Environment, Fisheries & Aquaculture Science
Cefas Lowestoft Laboratory
Pakefield Road
Lowestoft
NR33 0HT
UK
+44 (0)1502 562244
custodian
Data Manager
Centre for Environment, Fisheries & Aquaculture Science
Cefas Lowestoft Laboratory
Pakefield Road
Lowestoft
NR33 0HT
UK
+44 (0)1502 562244
pointOfContact
2016-07-14T12:28:23