Towards sustainable management: growth and population assessment of the deep-sea shrimp Aristeus alcocki Ramadan, 1938, in Southwestern Indian waters

Chakraborty, Rekha D and Gayathri, A P and Dash, Gyanaranjan and Maheswarudu, G and Josileen, Jose and Laxmilatha, P and Dineshbabu, A P and Varghese, Eldho and Kuriakose, Somy and Najmudeen, T M and Sreesanth, L and Ragesh, N and Retheesh, T and Sunil, K T S and Vijayan, M T and Augustine, Sindhu K (2025) Towards sustainable management: growth and population assessment of the deep-sea shrimp Aristeus alcocki Ramadan, 1938, in Southwestern Indian waters. Journal of Coastal Conservation, 29. pp. 1-18. ISSN 1874-7841

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Abstract

This study examines the population dynamics, growth parameters, exploitation status, and yield potential of Aristeus alcocki, a commercially significant deep-sea shrimp species in the North Indian Ocean. The species, identified as a prime candidate for certification by the Marine Stewardship Council, underscores the need to comprehend its fishery status for sustainable management. However, in recent years, frequent rise and falls in the landings and its corresponding CPUE has raised concern about the species. So, this study was designed to clarify the growth performance, stock status, and population dynamics of the mentioned species gathered from Kollam off Sakthikulangara along the Kerala coast, India. In this study, catch and effort data from 2007 to 2022 were utilized for the CMSY + + analysis, while biological data and population parameter estimations were based on data from 2017 to 2022. Size distribution analysis revealed peak abundances within specific size groups, with a sex ratio of 3.46 skewed towards females. Sex-specific differences were evident in length-weight relationships, with rapid growth rates observed for both. Findings of length-weight relationship analysis suggested a negative allometric growth trend for male (b = 2.69), female (b = 2.61), and pooled (b = 2.69) A. alcocki. Population parameters were evaluated utilizing the TropFishR package. Evaluation of VBGF-based growth parameters (L∞ and K) for male, female, and pooled categories indicated a higher asymptotic length for females (22.1 cm) compared to males (13.7 cm), and a higher growth coefficient in males (0.74 yr−1) compared to females (0.73 yr−1). The growth performance index (Ø′) remained consistent above 2.2 across these categories. Total instantaneous mortality (Z = 3.34 yr−1), fishing mortality rate (F = 1.86 yr−1) was estimated for pooled A. alcocki through length-converted catch curve analysis. The current exploitation rate (0.56) was found to be lesser than the Emax value (0.75) derived through Thompson and Bell analysis for pooled data. Thomson and Bell analysis revealed that standing stock (45.6%) and spawning stock biomass (32.9%) of which the earlier was below the reference limit (50%) while the latter was above the reference point limits of 25% respectively. The CMSY/BSM method revealed that the stocks of red ring fishery harvested by trawls in Kerala are currently in a healthy state (Bcur/Bmsy = 1.23), with a sustainable exploitation of Fcur /Fmsy = 0.52 which is well below the critical threshold of 1. Based on these findings, the study suggests maintaining the existing fishing pressure to safeguard the stability of the A. alcocki population, underscoring the crucial need to grasp the species’ current fishery status for sustainable management.

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