Purpose of this Web App
The app makes a forward projection of stock biomass, catches and revenues for a multi-gear fishery exploiting multiple stocks under different management scenarios. The projection uses the exploitation rates (fishing mortality) and initial stock state (biomass) from a base year derived from a Schaefer stock assessment model. The user can specify a range of effort changes that alter the exploitation rate to the whole fishery or individual gears. This allows a wide variety of potential scenarios to be explored by comparing changes in stock biomass, fleet catches and revenues over a specified time horizon.
Technical Details
The underlying prediction model is described here, and a description of the socio-ecological outcomes model is available here.
How to use this app
This app is designed to be used in a left-to-right fashion along the top naviation bar. Each tab is described below.
Configure Fleet Effort
This page allows for the configuration of the key inputs to the model. Primarily, the number of years over which to predict, and the fishing effort undertaken by each fleet, relative to its current effort (100%). The fleet effort is configured by selecting the fleet in the sidebar on the left-hand side. A yearly variation can then be set in the grey box at the top of the right-hand column. The evolution of the fleet’s effort is shown in the plot, which can also show the other fleets if the “Plot all fleets” box is checked in the left-hand sidebar.
The grey box below the plot can be used to copy the evolution from one fleet to others, and for complex procedures the data for each year can be edited by clicking on “Manually modify fleet effort table”.
Once a configuration has been completed it can be downloaded via the “Download” button, and a previous configuration can be uploaded via the “Upload Fleet Effort Table” option. These tables are in the comma separated value (CSV) format. An example can be found here.
Run Model
Once the model has been configured, this tab can be used to run it. For complete reproducibility the option to seed the random number generator is available. By default, this doesn’t need to be used, but results from runs with the same parameters will vary slightly. Simply run the model and proceed to the next tab.
Configure Prices
The prices for the different fish stocks caught by each fleet can be configured here. These can also be uploaded as a table in comma separated value (CSV) format. An example is available here.
Output & Synthesis
This page allows for viewing the results of the model and is composed of 3 tabs. The first tab (pictured) shows summary results which can be selected by the radio buttons in the grey left-hand sidebar. The “Specific Stock” tab shows the Fishing Mortality, Catch Rates, and Revenue for a particular stock, and the “Specific Fleet” tab shows the same for a particular fleet, as well as a reference fleet. The reference fleet is an amalgam of fleets, by default, the artisanal fleets (APW, Beach Seine, Set net, and Hook and line).
Download Data
The final tab allows for downloading all of the data associated with a particular model run. There is quite a lot of data to be generated, so this will take a while. Once the progress bar reaches 100% the download button will become active. Whilst the progress bar is filling, please don’t navigate away from this tab.
Model Progress
Preparing Download
Strathclyde Marine Modelling Group 2023.