- Title
- NAM CSR Fishing intensity of pelagic longline and pole-line vessels (Map 19d)
- Abstract
- Fishing intensity of pelagic longline and pole-line vessels from vessel monitoring systems (VMS). METHODS: · VMS point location data for all vessels in each of the nine fisheries were collated for the period 2014 – 2017. The data were cleaned, including removal of clear errors (e.g. points on land) and clipped to the study area. · Points were converted into a raster density layer, using a kernel density approach. This used a 0.005° cell size and a 0.075° search distance using planar units. · Density layers were then iteratively explored using a quantile based approach to identify the cut-off for very low density use areas and areas used for transit only, which for all industries identified the bottom 10% - 15% of used areas as being low use or transit only. The calibration was done on an expert basis. It identified the mean density of transit only zones, and then rounded this value up to the next 5 percentile mark. For the next steps only values above this threshold were evaluated. · Remaining areas were then split into 10 quantiles, from lower intensity use to highest intensity use. · The raster was then converted to a polygon layer. · Isolated port and anchorage polygons (which would have had high intensity values as vessels are often found there) were manually identified and exclude from the datasets. · The above approach gives a set of 10 intensity of use categories from lower intensity use (1) to highest intensity use (10). The areas deliberately exclude very low use areas.
- License
- Not Specified
-
+ The original author did not specify a license.
- Publication Date
- Dec. 30, 2021, 8:55 a.m.
- Keywords
- Category
- Fisheries
- fisheries related layers
- Regions
- Namibia
- Approved
- Yes
- Published
- Yes
- Featured
- No
- DOI
- None
- Attribution
- None
- Name
- Anja Kreiner (Anja)
- Anja.Kreiner@mfmr.gov.na
- Position
- Chief Fisheries Biologist, Chair: Namibia MSP NWG
- Organization
- National Marine Information and Research Centre
- Location
- Strandstreet 13001 Swakopmund Namibia NAM
- Voice
- +264 (0)64 4101158
- Fax
- +264 (0) 404385
- Keywords
- MSP
- Identification Image
-
- Spatial Extent
- ---
- Projection System
- EPSG:3857
- Extension x0
- None
- Extension x1
- None
- Extension y0
- None
- Extension y1
- None
- Language
- English
- Supplemental Information
- No information provided
- Name
- Anja Kreiner (Anja)
- Anja.Kreiner@mfmr.gov.na
- Position
- Chief Fisheries Biologist, Chair: Namibia MSP NWG
- Organization
- National Marine Information and Research Centre
- Location
- Strandstreet 13001 Swakopmund Namibia NAM
- Voice
- +264 (0)64 4101158
- Fax
- +264 (0) 404385
- Link Online
- /maps/268
- Metadata Page
- /maps/268/metadata_detail
- Name
- Anja Kreiner (Anja)
- Anja.Kreiner@mfmr.gov.na
- Position
- Chief Fisheries Biologist, Chair: Namibia MSP NWG
- Organization
- National Marine Information and Research Centre
- Location
- Strandstreet 13001 Swakopmund Namibia NAM
- Voice
- +264 (0)64 4101158
- Fax
- +264 (0) 404385
- Keywords
- MSP