Biometry, sexual maturity, natural mortality and fecundity of endangered halfbeak Dermogenys pusilla (Zenarchopteridae) from the Ganges River in northwestern Bangladesh

1548-1555The present study express the biometry, including length-weight relationships (LWRs) using 12 equations, length-length relationships (LLRs) using 15 equations, condition factors (allometric, KA; Fultonʹs, KF; relative, KR; and relative weight, WR), form factor (a3.0), first sexual maturity (Lm), natural mortality (MW) and fecundity (FT) of Dermogenys pusilla from the Ganges River, northwestern Bangladesh. A sum of 75 individuals was hardly collected using cast net and gill net during July 2013 to June 2014. In our study total length ranged from 6.6–16.1 cm for male and 7.5-15.6 cm for female and fin formula was- dorsal, D. 12 (4/8); pectoral, P1. 11 (2/9); pelvic, P2. 6 (1/5); anal, A. 13-14 (2-3/11-12) and caudal C. 18-20 (4/14-16). All LWRs were highly significant (P r2, BW vs. FL was the best fitted model among 12 equations for both sexes. The analysis of covariance (ANCOVA) revealed significant differences between males and females for LWRs (P P r2 values ≥ 0.940. According to highest value of r2, LLR by TL vs. FL was the best suited model among 15 equations for both genders. Based on Pearson correlation values, KF was highly correlated with BW and TL; thus KF can be used for the wellbeing of this species in the Ganges River. The a3.0 was 0.0025 for male and 0.0024 for female. The Lm was 9.70 cm TL for male and 9.40 cm TL for female. Also, the MW was 1.13, 1.41 year-1 for males and females respectively, and the fecundity was ranged from 620-1544 (mean ± SD = 1125 ± 248). Therefore, the findings of this study would be very effective for sustainable conservation of this endangered species in the Ganges River and surrounding ecosystem

Morphometric and meristic traits of three ambassid fish species (Chanda nama, Parambassis lala and Parambassis ranga)

398-405This research describes the first complete and inclusive information on morphometric and meristic characteristics of three Ambassid species (Chanda nama, Parambassis lala and Parambassis ranga) from the Mathabhanga River collected during August 2017 to July 2018. In our study, range of the total length was 2.0–7.2 cm for C. nama; 1.7-3.9 cm for P. lala and 1.9-6.4 cm for P. ranga. All length-weight relationships were highly significant (p r2 values ≥ 0.900 (except W vs. PrDL relationship in P. lala, where, r2 = 0.861). Also, all length-length relationships were highly correlated with r2 values being ≥ 0.900. Based on r2 value, W vs. FL and TL vs. FL was best fitted model for all the three species among the 11 equations. The calculated fin formula is: dorsal, D. 21–22 (VIII/13–14); pectoral, P1. 8–10 (2/6–8); pelvic, P2. 6 (I/5); anal, A. 17-18 (III/14–15); and caudal, C. 20–22 (4/16–18) for C. nama; D. 20–21 (VIII/12–13); P1. 8–9 (1-2/7); P2. 6 (I/5); A. 16-18 (III/13–15); C. 18–20 (4-6/14) for P. lala and D. 20–21 (VIII/12–13); P1. 9–10 (2/7–8); P2. 6 (I/5); A. 18-20 (III/15–17); C. 22–24 (4-6/18) for P. ranga. These outcomes will be a functional tool for identification of Ambassid fishes up to species level in any water-bodies of Bangladesh as well as in the adjacent countries

Life-history traits of Pool barb <em>Puntius sophore</em> (Cyprinidae) in different ecosystems of Bangladesh

1446-1454This study describes the life history traits of Puntius sophore (Hamilton, 1822) including, length frequency distributions (LFDs), length-weight relationships (LWRs), length-length relationships (LLRs), condition factors (allometric, KA; Fulton′s, KF; relative, KR and relative weight, WR), form factor (a3.0), first sexual maturity (Lm) and natural mortality (MW) from different ecosystems of Bangladesh. The LFDs were significantly different between the ecosystems (P b) of LWRs (TL vs. BW) indicated positive allometric growth in the Padma River and in the earthen pond (b > 3.0), but isometric growth was found in the Khoilla beel (b ≈ 3). All LWRs were highly significant (P r2 values are ≥ 0.931. The ANCOVA stated that, the LWRs were significantly difference between the ecosystems (P KF was best for assessing the wellbeing of this species in the surrounding ecosystems. The WR was not significantly different from 100 indicating the habitats were still in good condition for P. sophore. Calculated a3.0 were 0.0162, 0.0225 and 0.0125 in the River, pond and beel, correspondingly. The estimated Lm was 5.60 cm TL in River, 6.30 cm TL in pond and 4.90 cm TL in beel and MW was 1.45, 1.48 and 1.81 year-1 in the River, pond, beel respectively. The findings i.e. growth pattern, relative weight, size at sexual maturity, mortality etc. of this study will be effective for the implications of sustainable management policies and to initiate stock assessment practices in the worldwide different ecosystem