Step 7: Reference Points
There is no point in measuring the performance of a fishery with performance indicators if we can’t tell what the results of our measurements mean: is this level of the performance indicator that we find good or bad for the fishery? Does it help or hinder us in achieving fishery management goals?
To give the performance indicators meaning, we need targets and limits for each one. These are often called Reference Points (RPs). For some types of species and some PIs, there are commonly used RPs that are generally associated with sustainable fishing or a healthy stock. For other PIs or species types, stakeholders may have to determine their own RPs that are appropriate for their own goals and species life history characteristics.
Targets and limits should be adjusted according to risk tolerance and uncertainty. If uncertainty is high, for example because only one or two years of data are available, targets and limits should be more conservative to reduce the risk of overfishing.
For additional guidance on how to set reference points, see http://www.fao.org/docrep/003/v8400e/V8400E02.htm.
Here are some examples (the specific levels will depend on the species you are managing):
|Performance Indicators||Target RP||Limit RP|
|Fishing Mortality (F)||75% of natural mortality (M)||125% of M|
|Spawning Potential Ratio (SPR)||40%||20%|
|Catch Per Unit Effort (CPUE)||Within 10% of 5 year average||Below 50% of 5 year average|
|MPA Density Ratio||0.6||0.3|
For step-by-step guidance on identifying the appropriate RPs for your fishery, see the Guidance document for choosing PIs, identifying RPs, and defining HCRs in the downloadable workbook, and linked on this page.
Identifying RPs in a Multi-Species Fishery
As discussed at Step 6, the selection of Performance Indicators (PIs) and identification of appropriate Reference Points (RPs) is somewhat more complex in a multispecies fishery where management baskets are being used. In these cases, managers must ask themselves if PIs and RPs selected for the representative species for each basket will accurately represent trends and changes for the other species in the basket(s).
In some cases, a given PI may be suitable for all species in a basket, but different RPs may be appropriate for some species. For example, if Spawning Potential Ratio (SPR) is the selected PI, the appropriate target RP is 0.20 for fast growing species, and 0.40 for slow growing species. Thus, if a given management basket contains species with a wide range of growth rates managers must be careful to choose an RP for analysis that doesn’t put the slower growing species at risk, even if the representative species has a faster growth rate. In this example, an RP of 0.40 can be selected (regardless of the growth rate of the representative species) to be precautionary, or if managers have a slightly higher risk-tolerance, an RP of 0.30 could be selected as a mid-point between the fast and slow growing species’ SPR targets.