Good harvest controls news from IOTC / by Francisco Blaha

The Indian Ocean Tuna Commission (IOTC) adopted harvest control rules for skipjack tuna on 26 May at its annual meeting in La Reunion, a decision jointly lauded by some industry groups and many environmental organizations. The proposal was led by the Maldives, with the support of Kenya, Mauritius, Tanzania and Mozambique.

 Fish Market in Male, Maldives

Fish Market in Male, Maldives

The new rules include the identification of target levels of fishing to keep skipjack tuna populations from falling below dangerously low levels. They also call for a reduction of the use of fish-aggregating devices, ban the use of aerial vehicles, including drones, to find tuna schools and prohibit the use of lights at night to attract tuna. This decision is the culmination of months of meetings and collaboration among numerous organisations including fishers, industry groups and retailers.

And why is important for the Pacific? Because the DWFN there and those in the WCPFC are almost the same (people and countries). The WCPFC has so far only adopted a work plan for the development of harvest strategies but not much more than that (wrote about it here). We have now a concrete example of a CMM (Conservation and Management Measure) that countries have to follow.

Harvest Control Rules (HCR) are key to a fisheries management mechanism broadly named Harvest Strategies (I wrote about it here).

The proposal for a Harvest Control Rule (HCR) for IO SKJ draws on SC recommendations, including the new guidance on reference points in cases where MSY-based reference points are difficult to estimate. This proposal uses the biomass limit reference point of 20% of the unfished level (BLIM = 0.2B0) and the target biomass reference point of 40% of the unfished level (BTARG = 0.4B0), consistent with the SC advice that reference points based on depletion level should be used for stocks where MSY-based reference points cannot be robustly estimated and with international conventions and current practices followed in other tuna RFMOs.

The proposed HCR has three control parameters that can be tuned to provide better management performance with respect to the Commission’s management objectives and the underlying dynamics of the stock. The values currently proposed for these control parameters should be considered as “reference” values. After consideration of the performance statistics arising from these evaluations, the reference values currently used in this proposal may be replaced with alternative values that the Commission considers more appropriate.

It is important to note that this proposal does not seek to define a permanent HCR for the Indian Ocean skipjack tuna fishery. Rather, it will be necessary to continue work on the development of alternative, potentially better performing, HCRs as more data, improved analysis methodologies, and better scientific understanding of the stock is developed.

While the decision to preemptively create harvest control rules for skipjack before any possible population collapse could occur was lauded, a lot of people are frustrated by the lack of a similar agreement on yellowfin tuna, which (as in the Pacific) is in a worst state and in need of better management.