Weight-length, length-length relationships and form factor of three flatfish species from the Bay of Bengal, Bangladesh

Biometrics such as weight-length relationships (WLRs), length-length relationships (LLRs), as well as form factor (a3.0) were investigated for three flatfish species, Cynoglossus lingua, Cynoglossus arel, and Brachirus pan which were captured using seines and gill nets between September 2021 and March 2022 from the Bay of Bengal, Bangladesh. The lengths were measured to adjacent 0.1 cm accuracy with a digital caliper and weights to the accuracy of 0.01 g with a digital balance for each individual. The WLRs were accurately adjusted for all species (r2 > 0.9500). Brachirus pan had the lowest b value of 2.9543, whereas C. arel had the highest b value of 3.2924 amongst the three species. For the investigated species of fish, LLRs were also highly significant (r2 > 0.9600, p < 0.01). The estimated form factor values were 0.0023 for B. pan, 0.0026 for C. arel, 0.0027 for C. lingua. New maximum total lengths for C. arel and B. pan have also been recorded. Since there are no weight-length relationships (WLRs), length-length relationships (LLRs), as well as form factor (a3.0) data for these species in Bangladesh; the information supplied here expands the depth of knowledge for these species.