1991 - 1991 Centre for Environment, Fisheries & Aquaculture Science (Cefas) North Sea / English Channel Plankton Survey - RV Corystes 04/1991
Plankton data from Corystes 04/1991 as part of a series of 4 plankton surveys carried out in the North Sea and English Channel between 20th March - 28th June 1991. The aims were to study: - The distribution, abundance and production of sole ( - *Solea solea* - ) eggs as part of the ICES coordinated programme to estimate the female sole spawning stock biomass in divisions IVb, c, d, e. - The distribution and abundance of the planktonic stages of crab ( - *Cancer pagarus* - ), spider crab ( - *Maia squinado* - ) and bass ( - *Dicentrarchus labrax* - ). - The vertical distribution of crab larvae using the LHPR system. Plankton samples were collected at each site on a planned survey grid. This data consists of the numbers of fish eggs and larvae, along with associated positional data and volumes filtered, of the main net samples. It does not include the LHPR samples.
dataset
http://data.cefas.co.uk/#/View/3782/
function: order
CEFASf1c86382-6533-4da8-aec8-5ac8b6ddcf8b
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
2.5
52.5
49
revision
2010-05-18
1991-04-12
1991-04-18
publication
2020-01-30
notPlanned
Samples were collected using the 76cm high speed tow net fitted with a 40cm diameter opening nose cose and either a 270 or 600 μm mesh net and a Lyndhurst-Hardy Plankton Recorder (LHPR). Sampler deployment: The sampler was deployed in a double oblique tow from the surface to within 2 m of the seabed. Veering and hauling speeds were manually adjusted to ensure that each depth band was sampled equally. At shallow stations, multiple double oblique dives were necessary to enable a sufficient volume of water to be filtered. A minimum sampler deployment time of 15 minutes was aimed for. On recovery, the net was carefully washed down and the sample collected from the end bag. Each sample was then fixed using buffered formaldehyde solution and transported to the participating laboratories for sorting and identification. Sample analysis: Fish eggs and larvae were picked out from all samples by eye and, whenever practicable, the whole sample was sorted. However sub-sampling was at times necessary. Sub-sampling was carried out using a Folsom splitter. Fish larvae were readily identified unless they had been badly damaged during collection or were prematurely hatched. For some groups such as the sandeels (Ammodytidae) and the group of Gadidae commonly called rocklings, individuals were not identified to the species level. Fish eggs were initially split into three groups on the basis of the presence or absence of oil globules. Those containing either a single or many oil globules could usually be identified to the species level. Eggs with no oil globules were more difficult to identify. Some of these species such as cod ( *Gadus morhua* ), sprat ( *Sprattus sprattus* ), long rough dab ( *Hippoglossoides platessoides* ), dragonet ( *Callionymus* spp.) and plaice ( *Pleuronectes platessa* ) were identified because of their size or unique features. Unidentified eggs in this group were recorded as egg diameters. Data Storage: The raw data were stored in an Access database. The various data files were stored on the database in a series of tables linked by having the content of certain fields in common. All routine calculations, calibration changes and conversions were carried out in the database. The data tables (but not queries) have now been extracted into comma separated variable files. Plankton data are normally expressed as either number of organisms per m3 or per m2. These are calculated from the volume of water filtered (derived using regression co-efficients calculated for different flowmeters). Number per m3 is obtained by dividing the numbers per sample by the volume filtered, and number per m2 of sea surface is obtained by multiplying the number per m3 by the mean total or sampled depth during a deployment.
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
2020-01-30T10:25:07