1999-2001 University Marine Biological Station Millport (UMBSM) Clyde Sea Rapid Methodologies Survey

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Marine Environmental Data & Information Network
Last updated:
10 July 2024
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Summary

This dataset consists of pooled samples from the Clyde Sea portion of EC Study Contract 98/017. A study was carried out which investigated the effectiveness of rapid methodologies in quantifying the effects which otter trawls have on the marine environment. The research evaluates and compares rapid methodologies as alternatives to traditional (slow and costly) methods. Investigations were carried out on Norway lobster (Nephrops norvegicus) grounds in the Clyde Sea area, in Scotland, and a 'multi-species' fishery ground in the Aegean (Crete). Sample sites were selected to reflect a range of trawl impacts on the benthic environment. Scottish sites which were investigated covered three levels of fishing intensity; heavy, moderate and light. Aegean sites covered a succession of trawling intensities. An experimentally manipulated site was created off the island of Crete in an area previously unfished, to compare trawl impact. There were four categories of rapid methodologies which were evaluated. The categories include; acoustic, visual, biological and sedimentological. Acoustic methods of evaluating trawl impact included bottom discriminating sonar (RoxAnn(trademark)) and sidescan sonar. Trawling effects were detected by the latter. Visual methods included the use of underwater television, which was either deployed on a tow-sledge or on a remote operated vehicle (ROV). The study found that underwater television produced a better rapid assessment on the ecological impacts of trawling than other methodologies evaluated in this study. Biological methods investigated the tissue damage of selected species (molluscs, crustaceans, echinoderms), population density and the functional group composition of sampled communities. Benthic megafauna (mostly epifauna) was collected from sites of varying trawling intensity. A 2-metre beam trawl was used for sites in the Clyde Sea area while an Agassiz trawl was used for Aegean sites. Sedimentological methods of assessment included granulometry (geotechnical tests and sediment profile imagery (SPI). SPI provided a relatively rapid evaluation of trawled and untrawled site comparisons. The study provides a recommendation list of techniques which are suitable for rapid assessment of otter trawl impacts on soft substrata. The operational constraints and cost effectiveness of various methodologies are discussed.

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DASSH website N/A 10 July 2024 Not available
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Additional information

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Added to data.gov.uk
2023-11-29
Access contraints
Open Access
Harvest GUID
54b0db41aa9b52bd7e632c85958a6e3f
Extent
Latitude: 56.0000° to 55.5833°
Longitude: -5.1667° to -4.8333°
Spatial reference system
urn:ogc:def:crs:EPSG::0
Dataset reference date
2001-06-01 (publication)
2020-01-14 (creation)
2020-01-14 (revision)
Frequency of update
notPlanned
Responsible party
University Marine Biological Station (UMBS), Millport (originator); Data Archive for Seabed Species and Habitats (DASSH) (custodian)
ISO 19139 resource type
dataset
Metadata language
eng
Source Metadata
XML
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Licence information

Open Access; Open Government Licence