The results of this study support the idea that the main factor responsible for the
changes in the abundance of Blackspot Seabream in the Strait of Gibraltar is the
fishery component. The three approaches used to estimate the total biomass of this
species indicate that from 2010 the stock is kept at very low levels that oscillate
between 900 and 1600 t (Fig. 19.17). SimFish estimates that at least 64% of the
biomass variation is a consequence of fishery component. On the other hand,
estimates of the reference point (F 0.1 ¼ 0.12–0.17) from two of the models
(LCA-VPA and Gadget) are far above from current fishing pressure (about 0.3)
which reinforces the idea of a clear overexploitation of the resource.
On the basis of the above, the level of fishing effort should be reduced in order to
set the level of fishing mortality at a more sustainable level. This could be gradually
achieved by means of multiannual management plans that foresee a reduction of
fishing mortality through fishing limitations. However, nowadays there is no specific/joint management plan implemented for the Blackspot Seabream of the Strait of
Gibraltar. Both countries have different management measures on the target fishery,
but there are not any common ones towards its sustainability. There is a recent
recommendation to establish an adaptive multiannual management plan for the
sustainable exploitation of Blackspot Seabream in the Alboran Sea (GFCM/43/
2019/2). Its operational objective shall be to maintain fishing mortality for Blackspot
Seabream within agreed precautionary reference points in order to reach and maintain as soon as possible a fishing mortality level consistent with the MSY.
Therefore, the stock assessment of the Strait of Gibraltar Blackspot Seabream
target fishery is still subjected to a benchmark process within the GFCM. The
objective of the benchmark is to perform a full analysis and review of the information and methods used to provide advice on the status of the stock, focusing on the
consideration of old and new data sources as well as old and new (or improved)
assessment models and assumptions (WGBS 2018). Once this process is closed, the
next tool/step might be the development of management strategy evaluation (MSE)
Fig. 19.17 Comparison of results from three different approaches (VPA, Gadget, and SimFish)
used for the assessment of the Blackspot Seabream population of the Strait of Gibraltar
654
J. Gil-Herrera et al.
changes in the abundance of Blackspot Seabream in the Strait of Gibraltar is the
fishery component. The three approaches used to estimate the total biomass of this
species indicate that from 2010 the stock is kept at very low levels that oscillate
between 900 and 1600 t (Fig. 19.17). SimFish estimates that at least 64% of the
biomass variation is a consequence of fishery component. On the other hand,
estimates of the reference point (F 0.1 ¼ 0.12–0.17) from two of the models
(LCA-VPA and Gadget) are far above from current fishing pressure (about 0.3)
which reinforces the idea of a clear overexploitation of the resource.
On the basis of the above, the level of fishing effort should be reduced in order to
set the level of fishing mortality at a more sustainable level. This could be gradually
achieved by means of multiannual management plans that foresee a reduction of
fishing mortality through fishing limitations. However, nowadays there is no specific/joint management plan implemented for the Blackspot Seabream of the Strait of
Gibraltar. Both countries have different management measures on the target fishery,
but there are not any common ones towards its sustainability. There is a recent
recommendation to establish an adaptive multiannual management plan for the
sustainable exploitation of Blackspot Seabream in the Alboran Sea (GFCM/43/
2019/2). Its operational objective shall be to maintain fishing mortality for Blackspot
Seabream within agreed precautionary reference points in order to reach and maintain as soon as possible a fishing mortality level consistent with the MSY.
Therefore, the stock assessment of the Strait of Gibraltar Blackspot Seabream
target fishery is still subjected to a benchmark process within the GFCM. The
objective of the benchmark is to perform a full analysis and review of the information and methods used to provide advice on the status of the stock, focusing on the
consideration of old and new data sources as well as old and new (or improved)
assessment models and assumptions (WGBS 2018). Once this process is closed, the
next tool/step might be the development of management strategy evaluation (MSE)
Fig. 19.17 Comparison of results from three different approaches (VPA, Gadget, and SimFish)
used for the assessment of the Blackspot Seabream population of the Strait of Gibraltar
654
J. Gil-Herrera et al.