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Daily folders (16) of Simrad format (.raw) acoustic data. 16 daily folders of acoustic data (.ek5 format) 9 Echoview format (EV) format analysis files. Excel biological data for 16 pelagic hauls. CTD data for 27 vertical dips. Objectives: 1. To conduct an acoustic survey to estimate the abundance and distribution of mackerel in the northern North Sea (ICES division IVa). 2. To obtain samples of mackerel for biological analysis, including age, length, weight, sex and maturity. 3. To determine the species composition and target strength of fish in schools using the autonomous echosounder and video rig. 4. To make video observations of the multi-sampling pelagic trawl with the RCTV.
Scottish Government (Marine Scotland)
no limitations to public access
Other details | ||
Internal code | Internally assigned metadata identifier | 6202 |
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. | 1504S-North sea mackerel acoustic survey-Scotia cruise 1504 |
Alternative title | The purpose of alternative title is to record any additional names by which the dataset may be known. | North sea, Mackerel, acoustic survey, Scotia |
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. | Marine_Scotland_FishDAC_1754 |
Resource Identifier | This is the code assigned by the data owner. | Marine_Scotland_FishDAC_1754 |
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 | 2004-10-21 |
End date | This describes the date the resource ends. This may only be the year if month and day are not known | 2004-11-07 |
Spatial resolution | This describes the spatial resolution of the dataset or the spatial limitations of the service. | 55000.00 |
Spatial resolution unit | This describes the unit of spatial resolution which for distance must be metres. | http://standards.iso.org/ittf/PubliclyAvailableStandards/ISO_19139_Schemas/resources/uom/gmxUom.xml#m |
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'. | Not Planned |
Abstract | The abstract provides a clear and brief statement of the content of the resource. | Daily folders (16) of Simrad format (.raw) acoustic data. 16 daily folders of acoustic data (.ek5 format) 9 Echoview format (EV) format analysis files. Excel biological data for 16 pelagic hauls. CTD data for 27 vertical dips. Objectives: 1. To conduct an acoustic survey to estimate the abundance and distribution of mackerel in the northern North Sea (ICES division IVa). 2. To obtain samples of mackerel for biological analysis, including age, length, weight, sex and maturity. 3. To determine the species composition and target strength of fish in schools using the autonomous echosounder and video rig. 4. To make video observations of the multi-sampling pelagic trawl with the RCTV. |
Lineage | Lineage includes the background information, history of the sources of data, data quality statements and methods. | Scientific staff joined the vessel at 0900 on 21 October and the vessel departed at 1000. A small meeting was held with all scientists and the ship’s fishing mates and navigation officers to explain the objectives of the survey and to describe general operating procedures. The vessel proceeded to Scapa Flow to calibrate the acoustic transducers, however, prior to arrival it was evident that poor weather would prevent a successful exercise and so this was abandoned. The survey commenced on 22 October at 1347 at 61°55.5’N 001°00’W. Transects progressed southward along lines of latitude, at spacings of 15 or 7.5 nautical miles (nmi) as planned. Problems with the hydraulic systems on the vessel prevented any fishing operations from 2130 on 22 October until 1500 on 25 October. At 1520 on 27 October an opportunity was taken to calibrate the echosounders due to a break in the [poor] weather in Wick of Grunting, north of Fetlar, Shetland. The vessel docked into Lerwick harbour on 29 October for 24 hours to enable a change of personnel and to give staff their rest day in line with working time directives. The survey resumed at 1432 on 30 October. The first part of the survey was completed at 0656 on 4 November. The second survey commenced immediately, following a zig- zag design of the area of higher mackerel abundance along the 200 m contour: this was interlaced with a complementary survey carried out by the Norwegian FRV GO Sars. FRV Scotia completed its survey at 1320 on 5 November, after which the vessel rendezvoused with the GO Sars to carry out an intercalibration exercise starting at 2040. This lasted for approximately 7 hours (73 nmi) covering four transects with each vessel taking the lead alternately. The intercalibration was completed at 0400 on 6 November. The vessel returned to Aberdeen on the morning of 7 November. Results The survey was completed despite encountering long periods of poor weather. The total mileage surveyed was approximately 2435 nmi. A total of approximately 50 GB of acoustic data was archived and copied to DVD; this corresponds to 974 acoustic log intervals of 15 minutes duration. Successful calibrations were carried out of the three principal acoustic frequencies on the EK60 echosounder (38, 120 and 200 kHz). Echo traces from mackerel were distinguished on the basis of the difference in acoustic return between the 38 and 200 kHz frequencies, using the latest version of the FRS mackerel identification algorithm, which was displayed in real time (assisting the direction of ground truth trawl hauls). As expected, most of the mackerel were detected east of the border between EU and Norwegian waters, around Viking and Allen Banks. Ground truth identification and biological sampling of the mackerel echotraces was successful, with the PT160 able to catch large quantities of mackerel. Of the 16 trawl hauls carried out, mackerel were caught in 12, giving a raised total of 6 394 kg. 2042 mackerel were measured for length and 624 mackerel were sampled for weight, sex, maturity and otoliths. Other fish caught include herring (1513 lengths measured from a raised total of 4 830 kg), blue whiting (155 lengths), saithe (13 lengths), silversides, pearlsides, and a variety of small gadoids. No cod were caught. The deployment and recovery of the trawls passed, in most cases, without incident and no trawls were damaged. However, significant problems were encountered at the start of the survey with the hydraulic system associated with trawl winches. This and the poor weather encountered later in the cruise prevented sampling of mackerel in the northern part of the survey area. Biological samples from this area may be available from trawl catches taken by the GO Sars. The remotely controlled television (RCTV) rig was deployed once to observe the multisampling cod end on the PT160 pelagic trawl. After approximately half an hour of the first deployment, the RCTV cable failed at the point of previous damage and the system could not be used thereafter. Nonetheless, some excellent footage of mackerel streaming out of the open cod-end was recorded. After some other initial problems with the multisampling cod-end system, two tows were successfully completed on 4 November. In both cases this instrument provided data as it was designed to do: the trawl was aimed at three different scattering layers and came up with different proportions of species which coincided with that expected from a cursory examination of the multifrequency acoustic data. The poor weather encountered, combined with the relative scarcity of large mackerel schools close to the surface, prevented many deployments of the autonomous echosounder and video rig. On the one occasion when the rig was deployed with the vessel positioned reasonably well over a large mackerel school, it proved difficult to drop the rig close to the fish: only two fish were seen in half an hour of recording. However, acoustic data were successf |
Related keywords | ||
Keyword | General subject area(s) associated with the resource, uses multiple controlled vocabularies | Marine Environmental Data and Information Network |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Acoustics | |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Biota composition | |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Fish | |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Water column temperature and salinity | |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Acoustic backscatter in the water column | |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Fish abundance in water bodies | |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Fish biomass in water bodies | |
General subject area(s) associated with the resource, uses multiple controlled vocabularies | Fish morphology, age and physiology | |
Geographical coverage | ||
North | The northern-most limit of the data resource in decimal degrees | 62 |
East | The eastern-most limit of the data resource in decimal degrees | 4 |
South | The southern-most limit of the data resource in decimal degrees | 59 |
West | The western-most limit of the data resource in decimal degrees | -1 |
Regional sea | 51E9 | |
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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 | Scottish Government (Marine Scotland) | |
Phone | +44 (0)300 244 4000 | |
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 | Scottish Government (Marine Scotland) | |
Phone | +44 (0)300 244 4000 | |
Delivery point | Mailpoint 11, Area 1B South, Victoria Quay | |
Postal code | EH6 6QQ | |
City | Edinburgh | |
Country | United Kingdom | |
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 | Scottish Government (Marine Scotland) | |
Phone | +44 (0)300 244 4000 | |
Delivery point | Mailpoint 11, Area 1B South, Victoria Quay | |
Postal code | EH6 6QQ | |
City | Edinburgh | |
Country | United Kingdom | |
Role | The distributor is the person or organisation that distributes the resource. | distributor |
Organisation name | Scottish Government (Marine Scotland) | |
Phone | +44 (0)300 244 4000 | |
Delivery point | Mailpoint 11, Area 1B South, Victoria Quay | |
Postal code | EH6 6QQ | |
City | Edinburgh | |
Country | United Kingdom | |
Role | The originator is the person or organisation who created, collected or produced the resource. | originator |
Organisation name | Scottish Government (Marine Scotland) | |
Phone | +44 (0)300 244 4000 | |
Delivery point | Mailpoint 11, Area 1B South, Victoria Quay | |
Postal code | EH6 6QQ | |
City | Edinburgh | |
Country | United Kingdom | |
Resource locators | ||
Locator URL | Web address (URL) that links to the resource | https://www.bodc.ac.uk/data/information_and_inventories/cruise_inventory/search/ |
Locator function | Code that describes the function of the resource. ISO function code chosen from ISO 19115-1 Codelist | Reference info #0 |
Dataset constraints | ||
20 Limitations on Public Access - Access constraints | ISO restriction code chosen from ISO 19115-1 Codelist | otherRestrictions |
20 Limitations on Public Access – Other constraints | Any restriction on the use of the resource such as the need to agree to certain licence conditions. | no limitations to public access |
21 Conditions for Access and Use - Use limitation | Any restrictions imposed on accessing the resource such as the need to agree to certain licence conditions. | Open Government License (http://www.nationalarchives.gov.uk/doc/open-government-licence/) |
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. | 2016-05-09 |
Metadata date | The date when the content of this metadata record was last updated. | 2016-05-19 |
Metadata standard name | The name of the metadata standard used to create this metadata | MEDIN Discovery Metadata |
Metadata standard version | The version of the MEDIN Discovery Metadata Standard used to create the metadata record | Version 2.3.7 |
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