Title: An assessment of the Sardinella maderensis stock of Liberia coastal waters using the Length Based Spawning Potential Ratio (LBSPR).

Author(s): Anthony Ansu Yokie
Final project
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Supervisors: Warsha Singh


S. maderensis is an economically important species with high demand in Liberia. Due to over exploitation, this species is experiencing a collapse in the region. Consequently, it is imperative to understand more about its status. This study aimed to assess the status of S. maderensis in Liberia coastal waters using the length-based spawning potential ratio (LBSPR) approach. The study sampled length frequency data of S. maderensis from eight landing sites. The data were collected from April 2013 to September 2013, and March 2014 to October 2014. Length-frequency distribution was plotted together with key life history parameters L50, Lopt, Lmax, Linf to classify the length frequency sample into juvenile, mature, and mega-spawners. The results showed that in 2013, the maximum size of fish captured was 42 cm. The sample comprised 81.88% juveniles, 4.66% matured fish and 13.47% mega-spawners. Similarly, in 2014, the maximum size of fish captured was 42 cm, 82.22% of the captured fish were juveniles, while 8.25% were matured and 9.52% were mega-spawners. The estimated SPR was 0.23 for 2013 and 2014, and relative fishing mortality, F/M, was 0.97 and 0.99 for 2013 and 2014, respectively. The SPR values were estimated to be slightly above the target SPR of 20%, which indicates that this population is at risk of recruitment overfishing. The study recommended the use of monofilament gill nets to be replaced with multifilament gill nets; and to enforce the fisheries regulation to ban all gears with mesh sizes less than 50 millimetres.

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