Journal of Environmental Biology

Improving dolnet selectivity by assessing square mesh performance for covered codend experiment

S.K. Sharma1*, M.P. Remesan2, A.T. Landge3, V.R. Madhu2, S. Bhusan3, P.N. Jha2, K. Ramteke3 and S.R. Salunkhe1     

¹Fishing Technology Department, Mumbai Research Centre, ICAR-CIFT, Mumbai– 400 703, India

²Fishing Technology Department, ICAR- Central Institute of Fisheries Technology, Cochin– 682 029, India

³FRHPHM Department, ICAR- Central Institute of Fisheries Education, Mumbai– 400 061, India

Received: 03 July 2025                   Revised: 29 September 2025                   Accepted: 05 January 2026

*Corresponding Author Email : shravansharmacofsn@gmail.com                       *ORCiD: https://orcid.org/0009-0000-2541-1007

Abstract

Aim: The present study aimed to evaluate the impact of squaremesh modifications on juvenile escapement in dolnets.  

Methodology: The study was conducted in Karanja, Raigad district of Maharashtra, India, from April 2024 to March 2025, involving 15 sets of experimental dolnet hauls with fish targeted dolnet with square mesh codend modifications. Catch composition, size selectivity and bycatch were assessed through standardised fishing operations and morphometric measurements, with statistical analyses performed using R software to evaluate the efficiency of gear modifications.

Results: The cover codend experiment conducted at a depth of 15–20 m during pre- and post-monsoon season at Karanja, Raigad district, Maharashtra, India, revealed that dolnet catches were dominated by Harpadon nehereus (63.4% ± 6.4) and juvenile anchovies Coilia dussumeri, (13.7% ± 9.0). Frequent retention of juveniles in the codend was observed with 32.4% ± 4.7 of juvenile biomass recorded there and juvenile anchovy escapement reaching up to 47.8% ± 6.2. Selectivity analysis showed the 40 mm square mesh codend had an L50 of ~32 mm, allowing smaller fish to escape. Statistical tests confirmed reduced juvenile retention and improved selectivity in the square mesh design, supporting sustainable fisheries management.

Interpretation: The 40 mm square mesh codend improved the size selectivity by releasing juveniles, reducing bycatch and supporting sustainable dolnet fisheries in Maharashtra.

Key words: Catch composition, Codend experiment, Dolnet fisheries, Juvenile escapement, Square mesh selectivity

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