Southern Flounder, Uncertain Baseline Data
This week I wanted to look at the data used for management of southern flounder in North Carolina, specifically recreational catch data. Catch data is supposed to be baseline information in the fisheries management process. It is supposed to tell us how many fish were caught each year and allow managers to set quotas based on the health of the fish stock.
Accurate catch data is especially important when you are trying to rebuild a stock such as southern flounder. When trying to reduce the number of fish removed annually it is important to know how many fish were caught each year to compare that number with the fish caught the following year to see if you achieved your needed reduction. Simple math, right?
Well, what if every time you evaluated your strategy to see if you were achieving your reduction in catch the numbers changed? It’s pretty difficult to get the correct answers on a math test if the teacher erases and changes every math problem on the test AFTER you submitted your original answers! Well, that’s exactly what we are doing with our southern flounder management, at least with the recreational data.
Even since the original southern flounder FMP (fisheries management plan) in 2005, we have used a different set of recreational catch data every time we updated the plan (expect for Amendment 3 which was started as soon as Amendment 2 was finalized). Below is a table showing a side-by-side comparison of the changes in recreational harvest data (in pounds) in the 2005 original FMP document, Amendment 1 in 2013, and Amendment 2 in 2019.
Notice how only a couple of these harvest numbers are even remotely close to the previous data set. In fact, the average percentage change from 2005 to 2013 data and 2013 to 2019 data was over 50%!
Which set is correct?
Is any set correct?
How do we know if we are achieving our catch reductions (or if we even need any reductions at all!) if we do not even know if we have the correct baseline data?
Do you want to know why the recreational data for flounder (and other species) keeps changing and why the data will likely change again? If so, I will see you here again next week as we continue to dig further into these management issues plaguing our fisheries.