Trawl Survey Tool
Introduction
Using the Trawl Survey tool
Obtaining Catch Figures
Introduction
The 'Trawl Survey' tool is used to display details of the trawl survey catches of species in New Zealand waters. Trawl surveys are conducted by various suppliers under contract to the Ministry of Fisheries and stored in the Marlin database. You can select the species, area(s), year(s), month(s) and trawl survey. When a trawl survey is mapped and displayed, an individual trawl is represented by a circle. A filled circle represents catch for the selected species and a non-filled circle represents no catch for the selected species.
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Using the Trawl Survey tool
Select 'Trawl Survey' from the Layer Generation tools within the 'Select Layers' tab. An internet page opens allowing access to the following drop down lists:
| Field Name |
Function |
| Species |
Trawl survey data is primarily displayed by species. You can either select 'all species' or only one species from the drop down list. When a species is selected, only the trawl surveys where the selected species was caught will be available. The trawl survey data will be displayed for the selected species. |
| Area |
Trawl survey data can be filtered by area. You can select 'all areas' or a specific area from the drop down list. When an area is selected, only the trawl surveys that took place in the selected area will be available. |
| Year |
Trawl survey data can be filtered by year. You can select one or more or 'all years' from the drop down list. For multiple selections, hold down the 'Ctrl' or 'Shift' key and select the fishing years that you require. When a year is or years are selected, only the trawl surveys that took place in the selected year(s) will be available. |
| Month |
Trawl survey data can be filtered by month. You can select one or more or 'all months' from the drop down list. For multiple selections, hold down the 'Ctrl' or 'Shift' key and select the fishing years that you require. When a month is or months are selected, only the trawl surveys that took place in the selected month(s) will be available. |
| Trawl Survey |
The trawl survey list is determined by the selected species, area(s), year(s) and month(s). Tick the boxes to select a trawl survey.. You can select up to 5 trawl surveys from the list. Click on the 'Show Catch' button to map and display the selected trawl survey(s). Individual trawls are represented by a circle. A filled circle represents catch for the selected species and a non-filled circle represents no catch for the selected species. All filled circles should display the total catch of your selected species for that specific trawl. |
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How do I get the actual catch figures?
What's Here? tool
Select the 'What's Here?' tool from the 'Layer Tools' list available in the legend of the active layer or on the layer toolbar. Click on a filled circle on the map and the catch information will be displayed in the 'label_value' row. For more information about this tool see What's Here? Help.
Data View tool
Select 'Data View' from the 'Layer Tools' list available in the legend of the active layer. Catch information for the trawl survey is displayed for browsing in a spreadsheet format. Information about the total catch is displayed in the 'label_value' row. You can use the 'Data View' tool to select or highlight specific trawls. For more information about this tool see Data View Help.
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