Size-specific variations in the length-weight relationship and relative condition factor of Hilsa shad (Tenualosa ilisha) across its habitats in Bangladesh

• Published in: Heliyon Vol. 10; no. 13; p. e33586
• Main Authors: Faruque, Md. Hasan, Das, Rupesh
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.07.2024; Elsevier
• Subjects: Condition factors; Growth patterns; Habitat suitability; Hilsa; Size-variations; Size-variations; Habitat suitability; Condition factors; Hilsa; Growth patterns
• ISSN: 2405-8440; 2405-8440
• DOI: 10.1016/j.heliyon.2024.e33586

The length-weight relationship (LWR) and relative condition factor are widely used as the most important biological parameters to infer the growth pattern and well-being of fishes. The aim of our study was to investigate the growth parameters of the LWR in different growth phases of Hilsa (Tenualosa ilisha), a flagship species of Bangladesh, and compare its relative condition factors across its major habitats. Fish from various rivers in Bangladesh and the Bay of Bengal were sampled, their length-weight growth parameters were measured and subjected to statistical analysis with pooled data from other studies. An isometric growth pattern in Hilsa was predominantly found in the size classes of 25 ≤ TL (total length) < 30, 30 ≤ TL < 35, and TL ≥ 40. However, the size class TL < 25 showed negative allometric growth with the value of the exponent (b, also known as growth coefficient) between 2.797 and 2.833. The highest weight-growth of Hilsa was within the size class of 35 ≤ TL < 40, with exponent values of 3.271–3.381 (positive allometric growth) across habitats. Our results revealed that the exponent value varied significantly (P < 0.05) between different size classes of Hilsa except between 30 ≤ TL < 35 and TL ≥ 40; however, no such significant differences in the exponent values were found across habitats. The Akaike Information Criterion value was lowest for the size-specific length-weight regression model of Hilsa, indicating it was the best-fit model compared to the habitat-specific and pooled sample models. The relative condition factor of Hilsa by habitat was found in the order of Meghna > Bay of Bengal > Andharmanik > Biskhali > Tetulia > Padma. Additionally, the relative physiological well-being of Hilsa from the river Padma and Tetulia was poor compared to that of other habitats. A more in-depth analysis is required to determine the factors that can influence Hilsa's growth and well-being in relation to habitat quality. The present findings have significant relevance for fisheries biologists and managers in understanding and interpreting Hilsa's ecology, relative well-being of populations of same or contrasting habitats, demographic assessment, and for better management of Hilsa in the future. •The growth pattern of Hilsa (Tenualsa ilisha) was assessed in various size classes.•The physiological well-being of Hilsa was determined across its major habitats.•The highest growth in weight increment was in the size class 35 ≤ TL < 40.•The size-specific length-weight regression model was found to be the best-fitted model for Hilsa.•The health condition of Hilsa was best at Meghna and the worst at Padma.