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This work was part of the Fisheries Science Partnership (FSP), a Defra-funded collaborative programme of scientific research between the UK fishing industry and scientists. Local trawlermen working in the Bristol Channel and the South Wales Sea Fisheries Committee suggested that square-mesh panels fitted into trawls used to catch bass could reduce discards of undersize bass. A trawl was modified to incorporate a square-mesh section and was tested on board the MFV Cerulean against a control trawl. In August 2009, 46 hauls were conducted. Catches were sampled and video footage was taken of fish behaviour at the square-mesh section.
Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory (CEFAS)
Other details | ||
Internal code | Internally assigned metadata identifier | 11207 |
Title | The title is used to provide a brief and precise description of the dataset such as 'Date', 'Originating organisation/programme', 'Location' and 'Type of survey'. All acronyms and abbreviations should be reproduced in full. | Bristol Channel Bass Selectivity Survey 2009/10 - Fisheries Science Partnership |
Alternative title | The purpose of alternative title is to record any additional names by which the dataset may be known. | FSP Bristol Channel Bass Selectivity Survey |
File Identifier | The File Identifier is a code, preferably a GUID, that is globally unique and remains with the same metadata record even if the record is edited or transferred between portals or tools. | CEFASfa66b85d-c831-44ad-a259-f0ddf54026c5 |
Resource Identifier | This is the code assigned by the data owner. | CEFAS638 |
Resource type | The resource type will likely be a dataset but could also be a series (collection of datasets with a common specification) or a service. | dataset |
Start date | This describes the date the resource starts. This may only be the year if month and day are not known | 2009-08-01 |
End date | This describes the date the resource ends. This may only be the year if month and day are not known | 2009-08-31 |
Frequency of updates | This describes the frequency with which the resource is modified or updated i.e. a monitoring programme that samples once per year has a frequency that is described as 'annually'. | notPlanned |
Abstract | The abstract provides a clear and brief statement of the content of the resource. | This work was part of the Fisheries Science Partnership (FSP), a Defra-funded collaborative programme of scientific research between the UK fishing industry and scientists. Local trawlermen working in the Bristol Channel and the South Wales Sea Fisheries Committee suggested that square-mesh panels fitted into trawls used to catch bass could reduce discards of undersize bass. A trawl was modified to incorporate a square-mesh section and was tested on board the MFV Cerulean against a control trawl. In August 2009, 46 hauls were conducted. Catches were sampled and video footage was taken of fish behaviour at the square-mesh section. |
Lineage | Lineage includes the background information, history of the sources of data, data quality statements and methods. | Methods The gear The fishing gear normally used by the Cerulean in this fishery is a single-rig box trawl. Two single-rig box trawls are employed at different times; one of 13 fathoms the other of 14 fathoms. The trawls were of comparable design. The 14 fathom trawl had been modified previously to include a section of square-mesh netting near to the codend. This had been inserted by the skipper of the Cerulean to reduce the capture of undersized bass. For the FSP gear trials a new section of square-meshes of similar design to that used previously was fitted to the trawl. The panel was constructed from 90mm knotless square-mesh netting called Dyneema® with the guidance of Mike Montgomerie of Seafish. Both trawls had codends and extensions of 100 open meshes in the round. To account for the lack of flexibility of square netting and the narrowness of the extension, the panel was made with a width of 25 open bars with a baiting rate of 2 meshes to 1 bar for both ends of the panel. The panel was made to fit from selvedge to selvedge and 3 extra bars were used each side to allow for a 3 knot selvedge in each side. The length of the panel was agreed at 3 metres to keep it in line with other square-mesh panels used in UK, this would need a length of 68 bars (3.06m). An extra 1 bar was used each end to enable 2 bars to be laced together for extra strength at the end bar for joining on the diamond mesh. The panel was made so it could be inserted easily into either of the trawls. Two new 80mm mesh codends and lengtheners with conventional diamond meshes were used to ensure that any differences in trawl selectivity were not caused by differences in the codends. The square-mesh section was regularly changed between the two trawls to ensure any difference in selectivity was not due to the differences in the trawls. Consequently there were four trawl configurations: a 14 fathom trawl with and without the square-mesh section and a 13 fathom trawl with and without the square-mesh section. The trawl with the square-mesh section is hereafter called the experimental trawl, the trawl without, the control trawl. Sampling plan The trials took place in August, a period of good bass fishing in previous years, during 2 five-day trips. The trawl with the square-mesh section and the other without were deployed every day and the square-mesh section was swapped between the two trawls after each day. Normally only one haul was conducted at each location on the same day. This was usual commercial practice because it is believed that bass move away from an area when it is trawled. The method, therefore, assumed that the same assemblage of fish would be encountered by the control and experimental trawls during tows in similar locations during two five-day trips. The hauls were conducted in areas normally fished and were either on inshore trawling grounds off the North coast of Devon and Cornwall or on the ridges of sand banks further north in the Bristol Channel (Figure 5). The sand banks are fished specifically for bass and can yield high catches. The inshore fishing grounds are more generic trawling areas. A request for a derogation to conduct the work in Welsh waters was rejected so all hauls took place in English and EC waters. Cefas scientists measured the lengths of all fish species caught in each haul were where possible; samples of a known fraction were taken otherwise. Volumes of benthos were also recorded. Lengths were converted to weights using length-weight conversion parameters relevant to ICES Sub Area VII. Video camera During the second five-day trip an underwater video camera was used to film escape behaviour of bass and other species at the square-mesh section. A light sensitive EXPLORER 4K camera was mounted on a frame and attached to the top edge of the square-mesh panel pointing toward the codend. |
Related keywords | ||
Keyword | General subject area(s) associated with the resource, uses multiple controlled vocabularies | Biota abundance, biomass and diversity |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Fish behaviour | |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Species distribution | |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Water column | |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Marine Environmental Data and Information Network | |
Geographical coverage | ||
North | The northern-most limit of the data resource in decimal degrees | 53 |
East | The eastern-most limit of the data resource in decimal degrees | -2 |
South | The southern-most limit of the data resource in decimal degrees | 51.25 |
West | The western-most limit of the data resource in decimal degrees | -7 |
Responsible organisations | ||
Role | The point of contact is person or organisation with responsibility for the creation and maintenance of the metadata for the resource. | pointOfContact |
Organisation name | Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory (CEFAS) | |
Delivery point | Cefas Lowestoft Laboratory, Pakefield Road | |
Postal code | NR33 0HT | |
City | Lowestoft | |
Administrative area | Suffolk | |
Country | UK | |
Role | The originator is the person or organisation who created, collected or produced the resource. | originator |
Organisation name | Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory (CEFAS) | |
Delivery point | Cefas Lowestoft Laboratory, Pakefield Road | |
Postal code | NR33 0HT | |
City | Lowestoft | |
Administrative area | Suffolk | |
Country | UK | |
Role | The custodian is the person or organisation that accepts responsibility for the resource and ensures appropriate care and maintenance. If a dataset has been lodged with a Data Archive Centre for maintenance then this organisation is be entered here. | custodian |
Organisation name | Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory (CEFAS) | |
Delivery point | Cefas Lowestoft Laboratory, Pakefield Road | |
Postal code | NR33 0HT | |
City | Lowestoft | |
Administrative area | Suffolk | |
Country | UK | |
Role | The distributor is the person or organisation that distributes the resource. | distributor |
Organisation name | Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory (CEFAS) | |
Delivery point | Cefas Lowestoft Laboratory, Pakefield Road | |
Postal code | NR33 0HT | |
City | Lowestoft | |
Administrative area | Suffolk | |
Country | UK | |
Role | The owner is the person or organisation that owns the resource. | owner |
Organisation name | Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory (CEFAS) | |
Role | The owner is the person or organisation that owns the resource. | owner |
Organisation name | Department for Environment, Food and Rural Affairs (DEFRA) | |
Resource locators | ||
Locator URL | Web address (URL) that links to the resource | https://data.cefas.co.uk/view/638 |
Locator name | Name of the web resource | Cefas Data Portal |
Dataset constraints | ||
20.1 Limitations on Public Access - Access constraints | Any restrictions imposed on accessing the resource such as the need to agree to certain licence conditions. | otherRestrictions |
20.2 Limitations on Public Access - Other constraints | https://inspire.ec.europa.eu/metadata-codelist/LimitationsOnPublicAccess/ | |
21.1 Conditions for Access and Use - Use constraints | Any restrictions imposed on accessing the resource such as the need to agree to certain licence conditions. | otherRestrictions |
21.2 Conditions for Access and Use - Other constraints | http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/codelist/gmxCodelists.xml#MD_RestrictionCode | |
Version info | ||
Date of publication | The publication date of the resource or if previously unpublished the date that the resource was made publicly available via the MEDIN network. | 2016-11-14 |
Date of last revision | The most recent date that the resource was revised. | 2019-10-29 |
Date of creation | The date that the resource was created. | 2012-10-24 |
Metadata date | The date when the content of this metadata record was last updated. | 2019-10-29 |
Metadata standard name | The name of the metadata standard used to create this metadata | MEDIN |
Metadata standard version | The version of the MEDIN Discovery Metadata Standard used to create the metadata record | 3.1.1 |
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