1998 - 1998 Centre for Environment, Fisheries & Aquaculture Science (Cefas) Celtic Sea Plankton Survey - RV Cirolana 02/98
A trawl survey was carried out between 27th Feb - 31st Mar 1998 in the Celtic Sea. As additional aim of this survey fish eggs and larvae were collected in order to provide information on the timing of first spawning of mackerel and horse mackerel as part of the trienniel mackerel and horse mackerel survey. 8 plankton samples were taken using a 1.0m ring net. This data consists of the numbers of fish eggs and larvae identified, along with associated positional data and volumes filtered.
dataset
CEFAScfeedeb8-4163-458c-b867-ae19a2608c7f
http://www.cefas.co.uk/
eng
OGP
urn:ogc:def:crs:EPSG::4326
revision
2011-03-25
publication
2008-06-01
-13
-3
52.5
47
revision
2010-05-18
1998-02-27
1998-03-31
publication
2019-10-29
notPlanned
Samples were collected with a 1.0m ring net. 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 etc.) 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
+44 (0)1502 562244
pointOfContact
2019-10-29T10:09:44