Frequently Asked Questions

You can find the FishKit application here.  If it is your first time accessing the app you will have to create an account to gain access. Instructions to create an account are found on the login screen. FishKit is free and open for access to anyone in the world. Your information and data however stay private for you unless you decide to share. 

FishKit was developed by The Nature Conservancy and a group of practitioners and scientists involved with the FishPath program. During FishPath engagements it became clear that many fisheries often face a common set of management and monitoring challenges, and by developing FishKit The Nature Conservancy can support as many fisheries as possible on their paths to sustainability.

Different FishKit functionalities require different inputs. All modules have built-in examples so you can see what is possible before inputting your own fishery information. 

  • To use the Size Limit Builder you will need a life history. Learn more about life histories here
  • To use the Stock Health Tracker you will need a data set consisting of length measurements of fish. Data from fishery catch enable the widest range of functionality, but fishery independent data can also be used for some visualizations. 

The short answer is: it depends. Fisheries scientists have varying opinions on what constitutes sustainability for a fishery. The sustainability score in the Size Limit Builder is representative of the Spawning Potential Ratio (you can learn more about SPR here.) SPR can be used as a threshold below which the fish population is considered to be in an undesirable state. In this case, such thresholds are commonly defined between 20% and 40%, based on fish life history and other management considerations. SPR can also be used as a management target to be achieved. In this case, targets commonly range between 30% and 50% (sometimes higher), depending on life history and other management considerations.

Readings related to this topic:

There is no perfect answer for any fishery. The catch score in the Size Limit Builder is represented as a proportion of Maximum Sustainable Yield (MSY) or the long-term catch that maximizes the number of fish that can be sustainably harvested. While some fisheries may have an objective of maximizing yield, many fisheries scientists might argue for “pretty good yield” to take a slightly more conservative approach and to recognize the impracticality of attempting to optimally manage fishery resources. 

Readings related to this topic:

The scores presented in the Size Limit Builder represent an equilibrium. This equilibrium is projected to be reached at some point in the future. How long it takes for any fished population to reach this equilibrium is dependent upon the current status of the population (e.g., current sustainability score and current sizes in the catch) and the life history of the species. More productive species might recover more swiftly, while less productive species may take longer. For example, two different species like rabbits and elephants have very different life histories and therefore we can expect their populations to change on very different time scales. This same concept applies when thinking about different species of fish, where the differences in life history are just less obvious.  Any size limit that makes a portion of the size composition in the catch unavailable to fishing, will result in short term reductions in catch. To gain insights into how sustainability and catch might change over time as they approach equilibrium, you can visit the Transitional Dynamics tab (under development).

Estimation of life history parameters can often be uncertain, or there might be multiple life history parameters from different sources for a given fish. While there is no explicit simulation of life history uncertainty in FishKit, the Life History Repository allows for the creation of multiple life histories for any given species. This allows you to create variations of a life history with slightly different parameters, allowing you to evaluate how slight differences impact your results. With that said, we are constantly working to improve ways in which we address uncertainty in our models and are currently in the process of developing an even more robust solution to life history parameter uncertainty.

If you still have unanswered questions about FishKit, please reach out to us via our contact page.