Title: Evaluation of length-based stock assessment approaches: A preliminary assessment of the status of Pagellus bellotti and Galeoides decadactylus in Sierra Leone coastal waters

The length-based spawning potential ratio (LBSPR) and mean length mortality estimator (MLZ) are widely used methods for assessing status for data-poor fisheries management. The aim of this study is to conduct a preliminary assessment of the statuses of Pagellus bellotti and Galeoides decadactylus in Sierra Leone’s coastal waters using LBSPR and MLZ. The length-frequency data were collected from industrial fleets from 2018 to 2020. The estimated average spawning potential ratio (SPR) from the deterministic life-history parameters were 1.9% and 1.7% for P. bellotti and G. decadactylus respectively, while the average SPR from stochastic for P. bellotti and G. decadactylus were 1.7% and 2%, respectively. Both stocks’ SPR were found to be far below the limit reference point (SPR=20%), indicating that recruitment of these stocks is threatened. The length at which 50% of the fish were selected was less than the length at which 50% of the stock matured. This translates to high fishing pressure (F/M > 1) for both species. The MLZ average relative fishing mortality(F/M) obtained for P. bellotti and G. decadactylus were 3.56 and 3.26 respectively. These values are greater than one, indicating that the stocks are overfished. The LBSPR model captures the general trends in fishing mortality and the spawning stock biomass of the Icelandic cod stock assessment model with slight variation. This shows that the LBSPR can provide a cost-effective tool for analyzing data-limited stocks.