© OpenStreetMap contributors
- Add External Layer
- Upload Shapefile
- Close
Use the checkbox () to show or hide a layer.
Use the radio buttons () to select a layer to use with the identify function.
- Layers
- Opacity
Available layers
Search for marine data across UK organisations
- How-To
- About
- Contact MEDIN
- Share
Metadata: 1502S- North sea mackerel acoustic survey-Scotia cruise 1502
Abstract:
Daily folders (15) of Simrad (.ek5 format) data. 15 Echoview format (EV) format analysis files. Paper records of biological data for 16 pelagic hauls and 4 rod and line sampling. 9 XBT files. 11 Minilogger files. 15 Scanmar haul data files. 18 ITI haul data files. 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, maturity and ichthyophonus infection.
Data holder:
Scottish Government (Marine Scotland)
Use constraints:
no limitations to public access
Other details | ||
Internal code | Internally assigned metadata identifier | 6228 |
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. | 1502S- North sea mackerel acoustic survey-Scotia cruise 1502 |
Alternative title | The purpose of alternative title is to record any additional names by which the dataset may be known. | Mackerel, acoustic survey, north sea, scotia, 1502S |
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_1743 |
Resource Identifier | This is the code assigned by the data owner. | Marine_Scotland_FishDAC_1743 |
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 | 2002-10-10 |
End date | This describes the date the resource ends. This may only be the year if month and day are not known | 2002-10-26 |
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 (15) of Simrad (.ek5 format) data. 15 Echoview format (EV) format analysis files. Paper records of biological data for 16 pelagic hauls and 4 rod and line sampling. 9 XBT files. 11 Minilogger files. 15 Scanmar haul data files. 18 ITI haul data files. 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, maturity and ichthyophonus infection. |
Lineage | Lineage includes the background information, history of the sources of data, data quality statements and methods. | Scientific staff joined the vessel at 1100 hours on 10 October and the vessel departed at 1540 hours. A small meeting was held with all scientists and crew taking a navigational watch, to explain the objectives of the survey and to describe general operating procedures. The vessel then proceeded to Loch Eriboll where calibration of the four transducers was attempted starting at 0800 hours on 11 October: high winds prevented the exercise from being carried out successfully. Problems with the scientific echosounder were encountered and rectified using ships spares. The survey commenced in poor weather, north of the Minch, at 2022 hours on 11 October. Zig-zag transects at various spacings were adopted crossing the continental slope, progressing towards the north of Shetland. At this stage, the survey was severely hampered by gale force winds and the transect design was altered as a result. On reaching the northerly limit of the survey area, the weather improved and transects progressed southward along lines of latitude, at spacings of 30 or 15 nautical miles (n.mi.) as planned. The first fishing trawl was carried out on 14 October on the most northerly transect. On 16 October, the vessel made contact with the Norwegian FRV G.O. Sars as planned and the two ships carried out an interlaced survey in the Norwegian sector: transect spacing for each vessel was 30 n.mi. giving a combined effective spacing of 15 n.mi. When this was complete, the two vessels undertook an intercalibration exercise passing over areas where mackerel had been detected in the interlaced survey area. This lasted for approximately 115 n.mi. with each vessel taking the lead alternatively on three occasions. The intercalibration was completed at 2300 hours and the vessels then broke off to continue their respective surveys, with FRV Scotia surveying the UK area, east of Shetland. On 21 October, good weather provided an opportunity to calibrate the echosounders and this was carried out successfully in a calm bay south of Fetlar. After dropping off a crew member, the vessel resumed surveying at 1534 hours on 21 October. Storm force winds caused the vessel to suspend the survey at 1800 hours on 22 October to seek shelter in the approaches to Lerwick harbour. The survey resumed at 2130 hours on 23 October and was completed on 24 October at 2230 hours. The vessel returned to Aberdeen on the evening of 25 October. Results The survey was completed and, despite encountering some very high winds, only a small amount of time was lost due to weather. The total mileage surveyed was approximately 2130 n.mi. with 851 acoustic log intervals recorded. Successful calibrations were carried out of the three principal acoustic frequencies (38, 120 and 200 kHz); the 18 kHz was also calibrated although it is difficult to assess how accurately this was done at this stage. Echo traces from mackerel were distinguished on the basis of the difference in the acoustic return between the 38 and 200 kHz frequencies. Most of the mackerel were detected close to the border between EU and Norwegian waters, in the centre of the survey area, south of Viking Bank. Positive identification of the mackerel echotraces proved difficult. Of the 16 trawl • hauls carried out, mackerel were caught on only one occasion - when mixed with herring close to the bottom. It is quite clear that the PT160 is not able to sample mackerel in midwater. Fortunately, the crew of the Scotia were able to supply hooks, feathers, rod and hand lines. On four occasions, echo traces thought to be mackerel were fished on with this gear and in all cases reasonable quantities of mackerel were caught. In total, 201 of 222 mackerel were sampled for weight, sex, maturity and otoliths; of these, 168 were obtained by hook and hand line. It is clear that future surveys will need to consider alternative methods for sampling mackerel. The PT160 had no such problems catching other fish: over 10,000 herring were caught and 1,973 were measured for length. All three of the PT160 trawls were damaged. In all cases, the headline was parted from the top panel of the net. It is possible that the poor weather may have contributed to this but it is likely that insufficient control of the netsonde cable may also have contributed. On at least one occasion, the tension between the netsonde wire and the net was seen to be extremely high. On that occasion a Scanmar unit, attached to the headline, was severely damaged: no satisfactory explanation as to how this occurred has been put forward, but involvement of the steel netsonde mounting bar is suspected. Recovery procedures of the pelagic net need to be reviewed in the light of these observations. At the very least, it is suggested that the • steel netsonde wire be switched to the port side winch to avoid unnecessary carriage of the wire above the deck. It is also suggested that an alternative to the netsonde bar be sought. |
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 | 59.5 |
West | The western-most limit of the data resource in decimal degrees | -2 |
Regional sea | 48E8 | |
49E8 | ||
50E8 | ||
51E8 | ||
48E9 | ||
49E9 | ||
50E9 | ||
51E9 | ||
52E9 | ||
48F0 | ||
49F0 | ||
50F0 | ||
51F0 | ||
52F0 | ||
48F1 | ||
49F1 | ||
50F1 | ||
51F1 | ||
52F1 | ||
49F2 | ||
50F2 | ||
51F2 | ||
52F2 | ||
49F3 | ||
50F3 | ||
51F3 | ||
52F3 | ||
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 | otherRestrictions | |
20 Limitations on Public Access - Other constraints | This states any limitations on access to the data and uses free text. | no limitations to public access |
21 Conditions for Access and Use - Use limitation | This states any constraints on use of the data. Multiple conditions can be recorded for different parts of the data resource. If no conditions apply, then `No condtions apply` is recorded. This uses free text. | 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. | 2016-05-05 |
Harvest date | The date which this record has been (re)harvested from the provider. | 2024-04-21 |
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 |