Tuesday, 30 October 2018

Mapping the 2017 UK fishing catch

These infographics were produced by Chris Huggins currently working with the UK in a changing Europe team.

As part of our Brexit and fisheries policy project I recently put together an infographic showing where UK vessels catch their fish.
It did a pretty good job of highlighting that vessels from each of the UK’s four nations don’t just stick to that nation’s waters and why common frameworks will need to be given serious consideration in any post-Brexit UK fisheries policy.

A high-resolution PDF version can be downloaded here.

But it’s limited in that it doesn’t give you an immediately clear sense of the differences in how much each fleet catches. For example the Scottish fleet catches much more than the fleets in the other UK nations, but it’s not overly clear from the infographic how much more as it only really highlights where fish is caught.
I came across the idea of using a dot density map, so decided to give that a go.

The result

A high-resolution PDF version can be downloaded here.

How was it done?

I took a lot of inspiration from Alasdair Rae’s recent AIS tracking maps - he ended up with a really informative but stylish set of maps detailing marine traffic around the UK.
Data on the location of the UK’s 2017 fishing catch was made available by Marine Management Organisation in its recent 2017 annual fisheries statistics report(well worth a read!). This is reported in ICES statistical rectangles - grids of 0.5 degrees latitude and 1 degree longitude. I then summarised the data and calulated the number of points needed in each ICES rectangle for each of the UK nations, with each point represnting ten tonnes of fish. These points were then randomly plotted within each rectangle to represent the density of the catch.
I did all of this in R, which really pushed my limited skills to the limit. But it did allow me to learn a few new tricks, especially for manipulating the spatial data. For those into that sort of thing you can see my (not so elegant) code on GitHub.

Data sources

The data on fishing catch by ICES rectangle comes from the Marine Management Organisation. They publish a range of great statistics on fisheries - their annual sea fisheries statistics publication is well worth a read if you want to get an overview of fisheries.
The ICES statistical rectangles come from the International Council for the Exploration of the Sea.
To crop the rectangles along the coastline and to show land in the map itself I used the land polygons file from the Natural Earth website.
The bathymetry was downloaded from the NOAA within R using the marmap package.