1999 - 1999 Centre for Environment, Fisheries & Aquaculture Science (Cefas) Irish Sea Plankton Survey - RV Corystes 02/99
As part of the aims of this survey carried out from the 1st-25th March 1999 in the Irish Sea plankton samples were collected in the plaice spawning areas in the eastern Irish Sea. This data consists of the numbers of plaice eggs identified in the Gulf VII main net samples, along with associated positional and ancillary data and volumes filtered.
dataset
CEFASdf783bfe-cca0-4aab-a524-afb55f834312
http://www.cefas.co.uk/
eng
OGP
urn:ogc:def:crs:EPSG::4326
revision
2011-03-25
publication
2008-06-01
-4.5
-3.5
53.75
53.25
revision
2010-05-18
1999-03-01
1999-03-25
publication
2019-10-29
notPlanned
Samples were collected using an unencased 76 cm Gulf VII high speed towed net with a 40cm diameter nosecone opening and 270µm mesh" 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 laboratory 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 on 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 on the database. The data tables (but not queries) have now been extracted into text files. Plankton data are normally expressed as either number of organisms per m3 or per m2. The number per m3 is obtained by dividing the numbers per sample by the volume filtered, calculated from the sampler flowmeters. Number per m2 is obtained by multiplying the number per m3 by the mean 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
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pointOfContact
2019-10-29T10:09:44