DiscardLess project - Discard Mitigation Strategies Toolbox

Basque mixed demersal fishery in Bay of Biscay

The Basque trawling fleet operating in the Bay of Biscay is composed of bottom trawlers and their activity can be divided in four métiers. The first métier is the pair bottom trawl (PTB_DEF_>=70) targeting hake (Pair). This métier uses a very high vertical opening bottom trawl to target, mainly, hake. A second métier is the bottom otter trawl targeting demersal species (OTB_DEF_>=70) (Otter). Hake, megrims, and anglerfish are the main target species in this métier. However, this is a very mixed métier including many other species (pout, dogfish…). A third métier, only operates in the winter season of the year and is the Bottom otter trawl targeting mixed cephalopod and demersal species (OTB_MCF_>=70). Squids, cuttlefish, and mullets are the main target species in this métier although many other species (pout, seabass, hake…) are also harvested. Finally, there is a bottom otter trawl métier targeting a mix of demersal pelagic species (OTB_MPD_>=70), it also operates in the winter season. Apart from hake, this métier also targets mackerel and horse mackerel. These last two métiers have not been simulated independently (seasonal activity) but incorporated in the main Otter metier described above.

Model used

FLBEIA model Simulations have been performed using FLBEIA (Garcia et al., 2017). This is a simulation bio-economic model coupled in and providing feedback between all its dimensions (economic, biologic and social). It has been developed in R (R-Core, 2014) using FLR libraries. The model follows the Management Strategy Evaluation approach (MSE), which is widely used in fisheries management to analyse, by means of simulations, the performance of management strategies against predefined management objectives, before they are put in place. The approach of the simulation consists of projections over a given time period of the performance of the fleets that exploit the stocks under different management schemes. Two works have been performed, one is based on comparing the no LO situation and the LO situation under different exemptions to this LO (art 15 of the CFP). The second one is based on increasing the minimum mesh size to 100mm for pair trawlers

Conclusion :

LO will create a strategic game in which less discards and better selectivity are awarded. LO will not affect equally all the fleets involved and, hence, there will be, in relative terms, winners and losers, at least in economic terms. If exemptions are emended (in this case all the fleets have exactly the same amount and implemented in the same year), the winning-losing effects will be alleviated. If they are high enough, the fishery will back to the original situation (no LO). The higher the percentage of the exemption or flexibility (de minimis or both exemptions together) the weaker will be the redistributive effects and the final result will be closer to the no LO situation.

For the case of pair trawlers, the simulation performed showed no private incentives for increasing the MMS. However, this conclusion cannot be necessarily extrapolated to other areas or to other fleets. Other case-specific studies must be conducted to reach a detailed understanding of the subject. The lack of private incentives should not discourage the society from supporting the increase in the selective fishing activities. From the social perspective, there is room for incentives that increase the selectivity of the gear, at least for the fleet analysed in the present context. These incentives can be created by penalising the lower selectivity of the 100 mm MMS or rewarding (for example, with a higher quota or effort possibilities) the use of a more selective gear.

In general, the LO seems to provide better results than the previous situation of no LO. However, this is just partly an artefact of the simulation performed. It is true that the distributive effects of the uplift could benefit some fleets, and this work highlights this issue. Additionally, the lower overall catches (from other fleets fishing the same stocks) can benefit the Basque fleet. However, it has be mentioned that choke effect is not necessarily having an effect on an aggregated level but rather on an individual vessel level. This implies that this effect is clearly underestimated in the simulations presented here. Furthermore, the reaction of other fleets can be different from the one simulated here (in fact no reaction has been simulated) which can change the results significantly.

The simulations performed here do as such not give a final answer of what is going to happen but provides some insights on what are the main elements on what we should focus on for further evaluation of what the economic consequences will be for the Bay of Biscay fishing fleets given the implementation of the LO.

Results can be consulted Here using following password : Discardless