Blue Frontiers: Managing the environmental costs of aquaculture (Hall et al., 2011), from the World Fish Center is an incredibly data rich report. It is a must read for anyone interesting in the promise of aquaculture and the challenges involved in moving towards more sustainable practices.
The report contains data on the global distribution of aquaculture, relative importance of different species and differences in the environmental impact of different aquaculture practices. Figure 1, a cartogram showing global aquaculture production, circulated widely when the report was released last year.
In the “Looking Forward” chapter, Figure 4.3 is a bubble chart highlighting the countries that produce the greatest amount of exotic aquaculture species. There are two dimensions to the chart.
- The area of the bubbles show the total amount (in tons) of exotic species produced by each country.
- The color of each bubble indicates what percentage non-native species production is of total aquaculture production.
This is difficult information to communicate in a static graph. The bubble areas to a good job showing the countries with the greatest production of exotic species, but the colors showing the different percentages are difficult to interpret.
Leaving aside for a moment the question of whether a bubble chart is the best way to capture this data, I decided to see what it would look like as an interactive visualization. Click the colored boxes on the top right to change the state of the graph:
The illustration has two states. The “Total Exotic” state is as close as I could come to matching the original figure as a dynamic, force-directed bubble chart. it has the same 13 countries, and uses the same color scale. The “Percent Total” state scales the area of each bubble to represent total aquaculture production in each country. The percent of exotic species is shown as a proportion of the whole bubble.
If this was more than just an experiment, there are a few things I would have to deal with:
- The text labels do not fit the smaller bubbles. This makes some labels difficult to read when the bubbles are in certain positions. The bubbles can be dragged around to make them easier to read, but removing or properly sizing the labels would be better.
- If I was not trying to stay true to the original graph, I would change the color scale to make it easier to distinguish between the different percent bins.
- More interactivity could be added in response to hovering-over or clicking-on each country’s bubble.
About the data: The only values I took from the original figure (see page 58) were the tones of exotic species produced. I calculated total production by dividing exotic species production by their percent of total. Since the percentages are binned, I took the midpoint of each bin. As a result, the total values could be off by a much as 5 to 10% in some cases.
Hall, S.J., A. Delaporte, M. J. Phillips, M. Beveridge and M. O’Keefe. 2011. Blue Frontiers: Managing the Environmental Costs of Aquaculture. The WorldFish Center, Penang, Malaysia.