Fishing intensity and effort 2016-2021 (VMS data)

This dataset contains fishing intensity and effort data 2016-2021 based on VMS data. The data has been provided to ICES by Members States and processed to C-square resolution data products by ICES WGSFD on request by HELCOM. The data was used in HELCOM HOLAS3 SPIA analysis, CumI and Bycacth indicators.

## Anonymity considerations

In order to protect the anonymity of fishing vessels the values of certain attributes are not provided directly (in the case there are less than 3 fishing vessels present in that cell) and are instead given
a value of 'NA'. In order to allow time series and maps to be created for these sensitive attributes three
other values are provided for all cells, these are:

* x_cat: a character description of a range in which the attribute value falls into
* x_cat_low: the numeric lower bound of this category
* x_cat_high: the numeric upper bound of this category

where 'x' is the name of the attribute. The categories are calculated per year and are consistent across years and quarters. This
can be thought of as providing the colour grouping of a cell if plotted on a map, where the map scale is
consistent across years and quarters but with a separate scale for each gear and attribute.
The scales or categories are calculated simply by splitting the range of the attribute values into 10 equally spaced bins, for example if the range of the data is from 5 to 25, the bins would be (5-7, 7-9, 9-11, ..., 23-25).

The attributes considered sensitive are:

* Total Weight
* Total value
* Kw Fishing Hours
* Fishing hour

## a. All gear types: effort, especially need information on static gears to be included, i.e. FYK, GTR, GNS, LLS, FPO per month or quarter (minimum) of 2016-2022

### Temporal resolution:

* year (2016-2021)
* quarter

### spatial resolution:

* c-square

### Gear groups, e.g. (following level 3 of EU-MAP 2021/1167 table 5):

* Dredges (DRB),
* Bottom trawls (OTB, OTT, PTB, TBN, TBS),
* Pelagic trawls (OTM, PTM),
* Longlines (LL, LLS, LLD, LX),
* Traps (FPO, FYK, FPN)
* Nets (GNS, GTR, GND, GTN)
* Demersal seines (SDN, SSC)

### Dataset

* Effort in kW Fishinghours

### Anonymity

kW Fishinghours are subject to anonymity considerations.

## b.i. Intensity of mobile bottom contacting gears

### Temporal resolution:

* year (2016-2021)
* quarter

### spatial resolution:

* c-square

### Gear groups, only mobile bottom contacting gears:

* Total
* Dredge (DRB)
* Demersal seine (SDN, SSC)
* Otter trawl (OTB, OTT, PTB, TBN, TBS)

Benthis Metiers
* OT_CRU
* OT_DMF
* OT_MIX
* OT_MIX_CRU
* OT_MIX_DMF_BEN
* OT_MIX_DMF_PEL
* OT_MIX_CRU_DMF
* OT_SPF
* TBB_CRU
* TBB_DMF
* DRB_MOL
* SDN_DMF

### Dataset:

* Surface area in km2 (swept area)
* Surface SAR
* Subsurface area in km2 (swept area)
* Subsurface SAR
* Total weight
* Total value
* kW fishing hours
* Fishing hours

### Anonymity

Surface and subsurface area impacted, surface and subsurface SAR are not subject to anonymity constraints.

Total weight, Total value, kW fishing hours and Fishing hours are subject to anonymity considerations.

## b. Iii Provide the footprint of the grid cells that contain 90% of the highest fishing intensity of total fishing effort in the region. The resulting area or footprint can be defined as the core fishing grounds (or the smallest area that comprises 90% of the total swept area).

### Temporal resolution:

* year (2016-2021)
* quarter

### spatial resolution:

* c-square

### Gear groups, only mobile bottom contacting gears:

* All mobile bottom contacting gears.

### Dataset:

None, only c-squares in the footprint are provided.

### Anonymity:

No issues with anonymity

## b.iv The areal fraction per grid cell where 100% of the swept area occurs (alternatively fraction per grid cell without trawling)

### Temporal resolution:

* year (2016-2021)
* quarter

### spatial resolution:

* c-square

### Gear groups, only mobile bottom contacting gears:

* All mobile bottom contacting gears.

### Layers:

max_fraction_fished

### Anonymity:

max_fraction_fished is not subject to anonymity considerations.

### details

As data is provided to ICES at the c-square level, it is not possible to provide information at the sub c-square level therefore only the maximum fraction fished can be provided.

There are methods for modeling the fraction fished investigated by the ICES WGSFD. In addition, plans are being developed to request the fraction of substrate trawled by c-square in future data calls.

## Notes on shapefile field names

since shape files have a restriction that field names can only be 10 characters long, the following abbreviations have been made:

* sur = surface
* subsur = subsurface
* sur_sar = surface_sar
* subsur_sar = subsurface_sar

* kwfhr = kw_fishinghours
* kwfhr_c = kw_fishinghours_cat
* kwfhr_cl = kw_fishinghours_cat_low
* kwfhr_ch = kw_fishinghours_cat_high

* fhr = fishing_hours
* fhr_c = fishing_hours_cat
* fhr_cl = fishing_hours_cat_low
* fhr_ch = fishing_hours_cat_high

* totwt = totweight
* totwt_c = totweight_cat
* totwt_cl = totweight_cat_low
* totwt_ch = totweight_cat_high

* totval = totvalue
* totval_c = totvalue_cat
* totval_cl = totvalue_cat_low
* totval_ch = totvalue_cat_high

* max_frac = max_fraction_trawled