Intraspecific phenotypic differences in climbing perch Anabas testudineus (Bloch, 1792) populations may be linked to habitat adaptations

The climbing perch, Anabas testudineus, is a nutritionally and economically significant food fish. The present study reveals the first comprehensive description of the life-history traits of A. testudineus scooped up through different traditional fishing gears from July 2020 to December 2020. Among the 120 collected specimens, the smallest and largest specimens were 8.5 cm–14.6 cm TL in Nilphamari and Patuakhali, respectively. The estimated b values for LLRs indicated positive allometric growth in all sampling points (b > 1.0). The LWRs of A. testudineus indicated positive allometric growth in the Gazipur and Nilphamari districts (b > 3.00) and negative allometric growth in the Patuakhali and Khulna districts (b < 3.00). A Wilcoxon sign-ranked test for W(R) showed no significant dissimilarity from 100, signifying the balanced habitat for A. testudineus. The estimated a(3.0) was minimum in Khulna (0.0110) and maximum in Nilphamari (0.0825). “The Lm was estimated at 7.4032 (7.4) cm TL in Nilphamari and 8.86 (8.9) cm TL in Patuakhali”. Nineteen of twenty morphometric measurements and ten of twelve meristic characters showed substantial variations (p < 0.0001). The principal component analysis indicated shape variation and explained 85.361% of the total variance and showed differences in TL, SL, HL, LBD, LE1, D1D2, A1A2, and VV2. The cluster heatmap demonstrates that the other stocks segregated Gazipur stock. Our findings reveal a significant dataset about intraspecific phenotypic differentiation, which will aid the long-term exploration and management of A. testudineus species in Bangladesh and its neighboring countries.