Step 10: Interpretation

It is essential to carefully interpret the results of all these assessments, so that the management actions are based on the most accurate possible understanding of the status of the fishery.  If all of the performance indicators (PIs; Step 6) are at target reference point (RP; Step 7) levels, the Harvest Control Rule (HCR) set at Step 8 might be designed to maintain current harvest levels.  However, because fisheries are complex and many factors can influence the levels of performance indicators, sometimes the indicator levels may seem to conflict with each other, so they require some interpretation.  For example, if the two PIs selected are CPUE and the MPA Density Ratio, and completion of some of the assessment methods discussed at Steps 4 and 9 reveal that CPUE is at its target RP (suggesting that stock abundance and profits may be high) but the MPA density ratio is below its limit (suggesting that stock abundance may be low), it will not be immediately clear what the HCR should be.  Consulting with fishermen may reveal that CPUE is high in this assessment because (for example) a new patch of fish has recently been discovered, or because they have improved their targeting methods.  The most plausible interpretation of the CPUE and MPA density ratio indicator levels might then be that overall stock abundance has declined below target levels but fishermen are maintaining high CPUE because they have become more skillful in finding fish; if that is the case, then the HCR should dictate a reduction in fishing mortality in order to rebuild the stock to target levels. Thus, it is critical that traditional, local, and expert knowledge of the fishery be consulted when interpreting the results of data limited assessments.

Importantly, possible interpretations of the various performance indicator scenarios should take place with all stakeholders before actually conducting assessments -- so that there will be harvest control rules for every possible scenario of outcomes that have been agreed to ahead of time for maximum buy-in. The selected performance indicators and specific reference points should be re-evaluated and re-interpreted each year, prior to the start of the fishing season, so that appropriate fishery control measures can be set for the season (see Step 11).

Here is the example table from Step 8 showing each possible combination of 3 performance indicators - F, POPT (the optimal size for harvest), and SPR. Interpretations for each scenario, determined in concert with all stakeholders and based on in-depth local knowledge of the fishery, are presented in the second column from the right.  

Harvest Control Rule (HCR) Examples