Fish Stocks

Fish Species - Facts

Caught in: North Sea, eastern English Channel, Skagerrak

Caught in: North Sea, Skagerrak and Kattegat, eastern English Channel

Caught in: Northeast Atlantic and adjacent waters

Development of the Spawning Stock Biomass (SSB) over time

Explanation of graphs

The graphs of three different fish stocks, show the development of the spawning stock biomass (SSB) over a time period. SSB is an expression for how large a biomass (tons) that can spawn. When SSB is high it means many fish are mature and can spawn and vice versa if SSB is low. If SSB goes under the limit (Blim) advices by ICES the stock is in danger of collapsing – hence the red dots. If SSB is between Blim and a more precautionary limit Bpa, the stock is endangered – hence the yellow dots. Above Bpa the stock is in a great state – hence the green dots.


Original Idea

My original idea to this R shiny was to design an app where the consumers are the target group. The choice of target group stems from conversation with friends, that are not aware of which fish stocks are declining or increasing, and what the effect is of the attendant management. With this in mind, the app should provide information on the state of fish stocks in preferable Danish waters and around combined with the management of these stocks based on advice from ICES. The selected fish species should be those that are commonly eaten (“popular”) and caught mainly in Danish waters. After using the app the consumer should be able to answer the following questions:

- What is the status of different fish stocks in Danish waters? - How have each stock changed over time? - How are specific fish stocks managed? - And if the management does not have the desired effect, it is because the species in question is continuously overfished (despite the advice from ICES), or is it due to something else and thus not as a consequence of fishery?

The result

I have designed a simple and easy useable app. I applied a simple traffic light “method” to the graphs, which provides a great overview of the state of the different stocks. It is easy to choose between species, just by clicking on the drop down menu. Below this menu I inserted a box with a tabelpanel. By clicking on this panel, the user can see a picture and facts of each species.


Unfortunately I did not answer or clarify the management issues. This would be an interesting theme to elaborate by various graphs. And would support and strengthen the knowledge of the consumer, guiding them when choosing fish in the supermarket. More interactive features could be added. I did try with sliders, but the way the app is now, sliders blurred the message. If it is further developed other interactive features might fit in.


The International Council for the Exploration of the Sea (ICES) is an intergovernmental marine science organization, meeting societal needs for impartial evidence on the state and sustainable use of our seas and oceans.

The above cite is from ICES webpage. The organization provides advice and produce advice sheets on fish stocks all over the world, and tries to help managing the oceans’ resources. They also play a role in the communication between NGOs, governments, fisheries organizations etc.



Data for graphs provided by Mikael van Deurs

App designer and developer: Nicoline Jessie Jørgensen