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ASSESSMENT OF THE EXPLOITATION STATUS AND POTENTIAL OF THE MAIN FISH STOCKS IN TUNISIAN RESERVOIRS

Authors Tahani Chargui¹, Rym Ennouri^2,3, Siwar Agrebi⁴, Fehmi Boufahja^5,*, Houcine Laouar⁶, Sami Mili^4,7*

Published 30 December 2025 Volume 3:2 Pages 229-251

Checked for plagiarism Yes

Peer reviewer comments 2

¹University of Carthage, National Agronomic Institute of Tunis, 43, Street Charles Nicolle 1082, Mahrajène, Tunis, Tunisia.

² University of Carthage, Higher Institute of Marine Sciences of Bizerte, Errimel, B.P. 15,7080 Bizerte, Tunisia.

³ Laboratory of Ecology, Biology and Physiology of Aquatic Organisms, Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis, Tunisia.

⁴ University of Carthage, Faculty of Sciences of Bizerte, Zarzouna, 7021 Bizerte, Tunisia.

⁵ Biology Department, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11623, Saudi Arabia.

⁶ Technical Center of Aquaculture, Tunis, Tunisia.

⁷University of Carthage, Laboratory of Fisheries Sciences, National Institute of Marine Sciences and Technologies, 28 rue du 2 mars 1934, Salammbô 2025, Tunis, Tunisia.

*Correspondence: sami.mili@fsb.ucar.tn

Abstract

Assessing the status and potential of fish stocks in Tunisian reservoirs is essential for the sustainable management of inland fisheries, which play a vital role in rural development and food security. This study aims to estimate biomass and evaluate the exploitation status of six key species: common carp (Cyprinus carpio), thin-lipped grey mullet (Chelon ramada), barbel (Luciobarbus callensis), pikeperch (Sander lucioperca), rudd (Scardinius erythrophthalmus), and roach (Rutilus rubilio), across eight major Tunisian reservoirs: Bir Mcherga, Sidi Saad, Siliana, Kasseb, Sidi Barrak, Sidi Salem, Mellegue, and Lahjar. Standardized scientific gillnet sampling was conducted between 2013 and 2016. Population parameters (L∞, K, t₀, and natural mortality, M) were estimated using FISAT II software. Stock status was assessed through a yield-per-recruit (Y/R) model implemented in VIT software. The results indicate a general pattern of under-exploitation across most fish stocks, suggesting considerable potential for increased sustainable yields. However, notable variability was observed among species and reservoirs. Common carp were found to be near optimally exploited in Sidi Saad (E = 0.48), but under-exploited in Bir Mcherga (E = 0.30). Thin-lipped grey mullet exhibited very low exploitation levels (E = 0.09), indicating that stocking efforts are not being fully utilized. Despite relatively high fishing mortality (F exceeding 60% of total mortality) in species such as barbel and pikeperch, yield-per-recruit analysis still classified these stocks as under-exploited due to their high biological productivity. In conclusion, Tunisian reservoirs possess significant underutilized fisheries potential. The findings highlight the need for site- and species-specific management strategies, including a controlled increase in fishing effort for under-exploited stocks, to maximize sustainable fields while ensuring long-term resource conservation.