Identification

Title

1990 - 1990 Centre for Environment, Fisheries & Aquaculture Science (Cefas) Bristol Channel, western English Channel, Celtic Sea Plankton Surveys - RV Corystes 05/1990

Abstract

Analysis of plankton samples collected on a series of surveys in 1990 to determine the extent and timing of sole (Solea solea) spawning. Numbers of ichthyoplankton, Nephrops larvae and edible crab (Cancer pagurus), along with associated positional and environmental data (temperature and salinity).

Resource type

dataset

Resource locator

Unique resource identifier

code

CEFASa4055838-62f0-4992-aeb0-097c2112b0a0

codeSpace

http://www.cefas.co.uk/

Dataset language

eng

Spatial reference system

authority code

OGP

code identifying the spatial reference system

urn:ogc:def:crs:EPSG::4326

Classification of spatial data and services

Topic category

Keywords

Keyword set

keyword value

Keyword set

keyword value

originating controlled vocabulary

title

reference date

date type

revision

effective date

2011-03-25

Keyword set

keyword value

originating controlled vocabulary

title

reference date

date type

publication

effective date

2008-06-01

Geographic location

West bounding longitude

-12

East bounding longitude

-1

North bounding latitude

52.5

South bounding latitude

48

Extent

Extent group

authority code

title

reference date

date type

revision

effective date

2010-05-18

code identifying the extent

Temporal reference

Temporal extent

Begin position

1990-04-01

End position

1990-04-26

Dataset reference date

date type

publication

effective date

2019-10-29

Frequency of update

notPlanned

Quality and validity

Lineage

A series of surveys to estimate the spawning stock biomass of sole (*Solea solea*) in the Bristol Channel area (see also separate records for surveys Corystes 4 and 6/89), western English Channel and Celtic Sea. Identity where possible of all species of fish eggs and larvae determined. Developmental staging for eggs of sole and plaice and for edible crab larvae undertaken. Data consists of the numbers of fish eggs and larvae, crab larvae, along with associated positional data and volumes filtered, from the main net samples. It does not include all LHPR sample analysis. **Associated Datasets: **Temperature and salinity "V" profiles are available at each sampling position. Continuous near-surface (3m) temperature and salinity data are available for complete cruises. Samples were collected using a 76cm High Speed Tow Net, a 53cm Tow Net fitted with a Guildline Conductivity Temperature Depth (CTD) monitoring system and a Longhurst-Hardy Plankton Recorder.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 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.

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Public data (Crown Copyright) - Open Government Licence Terms and Conditions apply

Constraint set

Limitations on public access

Public data (Crown Copyright) - Open Government Licence Terms and Conditions apply

Responsible organisations

Metadata on metadata

Metadata point of contact

contact position

Data Manager

organisation name

Centre for Environment, Fisheries & Aquaculture Science

full postal address

Cefas Lowestoft Laboratory

Pakefield Road

Lowestoft

NR33 0HT

UK

telephone number

+44 (0)1502 562244

email address

data.manager@cefas.co.uk

responsible party role

pointOfContact

Metadata date

2019-10-29T10:09:44

Metadata language