Accounting intra-annual variability in mortality and recruitment in stock status evaluation of Parapenaeopsis stylifera fishery of north-eastern Arabian Sea under moderate data scenario

Abstract

Length-based integrated mixed effect (LIME) approach was applied for the assessment of Parapenaeopsis stylifera stock, the most prominent penaeid resource along Gujarat coast. Month was selected as a temporal step size to improve estimate precision and capture intra-annual variation in population dynamics. Catch was provided as an additional input to create a moderate data scenario and reduce bias in estimates of reference indices. The values of key life history priors Linf, K, M, t0, Lm50, Lm95 were 160.59 mm total length (TL), 1.68 yr−1, 2.406 yr−1, −0.01 yr, 89.1 mm TL, 95.06 mm TL, respectively. The LWR was established as W = 0.0117*TL2.652. The estimated SPR ranged between 0.33 and 0.70. The monthly fishing mortality was estimated between 0.06 and 0.31. In 37.5% of the observed month, the fishing mortality was above optimum, which by and large coincides with the peak fishing months. The recruitment is continuous, with a coefficient of variation of only 18.5%. Based on these indices, the stock can be considered as healthy or sustainable. A continuous monitoring and collection of abundance data through experimental surveys are recommended as a future course of action.