Fishery Stock Appraisal of Trichiurus lepturus (Linneaus, 1758) by using SPMs: A Case Study of Shandong, China
Fishery Stock Appraisal of Trichiurus lepturus (Linneaus, 1758) by using SPMs: A Case Study of Shandong, China
Zhang Yan1,2 and Muhammad Mohsin3*
ABSTRACT
Stock assessment of commercial fisheries is very important to ensure sustainable harvesting of fishery resources in China. Therefore, this study endeavors to estimate the fishery status of Trichiurus lepturus in Shandong, China. For this purpose, fishery statistics, 2007–2018 were statistically evaluated by surplus production models (SPMs). These models were applied to data through computer-based manually operated statistical routines, viz., ASPIC (a stock production model incorporating covariates) and CEDA (catch and effort data analysis). For the principal input (IP) value of 0.9, the former software suggested a maximum sustainable yield (MSY) of around 65,000 tons (t), whereas the latter one calculated MSY as 71,000 t. In ASPIC, coefficient of variation (CV) and R2 for Fox Model (F-M) and Logistic Model (L-M) remained at 0.113, 0.982 and 0.055, 0.895, respectively. Meanwhile, in CEDA, MSY outputs remained 72,082 t and 80,723 t (on average) for F-M and Schaefer Model (S-M) or Pella-Tomlinson Model (PT-M), correspondingly. Besides, it was found that fishing mortality (F) has increased from 0.510 (2007) to 1.099 (2018) whereas biomass t has decreased from 320,100 t (2007) to 68,890 t (2018), F-M in ASPIC. Estimated parameter values vividly signpost overharvesting of T. lepturus in Shandong, China. Thus, current management measures should be further strengthened for sustainable harvesting of this fishery resource and additional research on this topic.
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