Step 5. Initial Fishery Assessment
After conducting a PSA on target species, the status of individual fish targets was assessed. Because NGOs and some fishermen had measured the lengths of individual fish in the catch over the last few years, length-based methods were used to calculate fishing mortality (F) as an indicator to assess the status of each target in this step. Specifically, the mean length (LBAR) method was used for this initial assessment.
The length composition of fish in the catch (the number of individual fish in each size category) can be used to calculate indicators of whether or not fishing is sustainable. Because fishing tends to reduce average fish size, declines in fish size can also be a useful indicator of overfishing and overfished status. If the estimated fishing mortality is two to three times greater than natural mortality (F>2M), it is an indication of high fishing pressure and poor stock status. If the estimated fishing mortality is closer to, but still greater than natural mortality (F>M), it is an indication of moderate fishing pressure and a moderate stock status. If the estimated fishing mortality is less than the natural mortality (F<M), it is an indication of low fishing pressure and a healthy status. LBAR results for each species captured in this hypothetical multispecies fisher are presented in the table below.
This fishery recently began collecting data on the catch over the last two years, and fishery independent data collection started this year. For the stakeholders, this is the beginning of a process to adapt data collection and monitoring efforts for this multispecies fishery. In the future, the stakeholders will adapt monitoring efforts to help measure progress towards each of their fishery management goals.
Preliminary Assessment with LBAR: