Temporal variations of sex ratio and growth pattern of critically endangered catfish Clupisoma garua from the Ganges river of north-western Bangladesh

647-653This research work states the temporal variations of sex ratio (SR), length-frequency distributions (LFDs), growth type based on length-weight relations (LWRs) and length-length relations (LLRs) of Clupisoma garua from the Ganges river of north-western Bangladesh. A total of 1200 specimens (male=630, female=570) were sampled using traditional fishing gears during May 2014 to April 2015. Then, total length (TL), standard length (SL) and fork length (FL) were taken to about 0.1 cm, and body weight (W) was taken to 0.1 g accuracy. The overall SR (male: female=1.0:0.90) did not vary statistically from the expected ratio of 1:1 (df =1, χ2 = 3.00, p>0.05). However, monthly variations of SR indicate males were higher in each month except June-August when females were greater in percentage. The LFDs showed that in males C. garua, ranged from 3.8-25.9 cm TL and females 3.9-26.3 cm TL. The LFDs for both sexes did not pass the normality; and Mann-Whitney U-test showed significant differences between sexes (pbvs. FL and TL vs. SL) of C. garua were highly significant (pr2 values >0.975. Finally, the findings of this study will be helpful for fishery biologists and conservationists to recommend adequate policy for the sustainable fishery of C. garua in the Ganges river and surrounding ecosystem

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

UGROŽENE VRSTE RIBA U SVIJETU: Labeo calbasu (Hamilton, 1822) (Cypriniformes: Cyprinidae)

Orangefin labeo Labeo calbasu is one of the commercially and nutritionally valuable food fish in Asian countries including Bangladesh, India, Nepal, Pakistan, Thailand and China. Unfortunately, natural populations of this species are decreasing due to over-exploitation and various biological changes to its habitats. This article suggests the steps for the conservation of the remnant isolated population of Indian major carps, L. calbasu, in the waters of Asia.Narančastoperajni labeo, Labeo calbasu, je visoko nutritivna vrijedna hrana u azijskim zemljama, uključujući Bangladeš, Indiju, Nepal, Pakistan, Tajland i Kinu. Nažalost, prirodne populacije ove vrste se smanjuju zbog pretjeranog iskorištavanja i raznih bioloških promjena u njihovim staništima. U ovom članku predlažu se koraci za očuvanje ostatka izolirane populacije indijskih velikih šarana, L. calbau, u vodama Azij

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

Life-history Traits of the Blacktrip sardinella, <i> Sardinella melanura</i> (Clupeidae) in the Gwadar, Balochistan Coast, Pakistan

397-404The present study describes the first complete and comprehensive description on life-history traits of Sardinella melanura including length-frequency distributions (LFDs), length-weight relationships (LWRs), condition factors (allometric condition, KA; Fulton’s condition, KF; relative condition, KR), and relative weight (WR) in the Gwadar, Balochistan Coast, Pakistan. Additionally, form factor (a3.0) using available a and b regression parameters of LWRs and size at first sexual maturity (Lm) using available maximum length for 07 Sardinella spp. in 23 water-bodies were calculated. Seasonal samples of S. melanura were collected from the Gwadar, Balochistan Coast, Pakistan using gill nets during July 2013 to June 2014. Total length (TL) was measured to nearest 0.1 cm using digital slide calipers and total body weight (BW) was measured using an electronic balance with 0.1 g accuracy for each individual. A total of 600 individuals of S. melanura were analyzed, where minimum and maximum TL was 12.5 cm and 23.00 cm, respectively and BW was 16.5g and 114.8 g, correspondingly. Highest number (25.83%) of its population stands at 17.00 cm to 18.00 cm size group. The b value of LWR indicated negative allometric growth in the population. All the condition factors (KA, KF, KR, and WR) were significantly correlated with TL and BW (P &lt; 0.001). WR showed significant difference from 100 (P &lt; 0.001) representing imbalanced population in presence of prey and predator. In addition, the a3.0 for S. melanura was 0.0078. The size at first sexual maturity (Lm) was 14.43 cm in TL of S. melanura in the Gwadar, Balochistan coast, Pakistan

Temporal variations of condition and prey-predator status for two Halfbeaks (<i>Hemiramphus archipelagicus</i> and <i>H. lutkei</i>) in the Karachi Coast of Pakistan through multi-model inference

562-568The present study focuses on the temporal variations of condition through multiple functions (allometric, KA; Fulton's, KF; relative, KR) and prey-predator status through relative weight (WR) for two halfbeaks, Hemiramphus archipelagicus (Collette & Parin, 1978) and Hemiramphus lutkei (Valenciennes, 1847) using the monthly samples from the Karachi Coast of Pakistan during January to December 2014. The smallest individual was 14.0 cm in TL for both species, but the largest individuals were 23.5 in TL for H. archipelagicus and 27.8 cm in TL for H. lutkei. The BW ranged from 8.0-27.4 g for H. archipelagicus and 7.0-37.4 g for H. lutkei. There was significant differences in length-frequency distributions (LFDs) between two species (PKF was highly correlated with TL for both species (Spearman rank test, PKF is the best condition factor for assessing the wellbeing of this two Halfbeaks in the Karachi Coast of Pakistan. There was no significant relationships between TL vs. KA (rs=-0.0264, P=0.056 for H. archipelagicus and rs=-0.0883, P=0.855), TL vs. KR (rs=-0.0108, P=0.813 for H. archipelagicus and rs= 0.0235, P=0.608) and TL vs. WR (rs=-0.0099, P=0.828 for H. archipelagicus and rs=0.0235, P=0.608 for H. lutkei), but significant relationships were found in TL vs. KF, BW vs. KA,BW vs. KF, BW vs. KR and BW vs. WR (PWR was not significantly different from 100 (Wilcoxon signed rank test , P=0.654 for H. archipelagicus and P=0.405 for H. lutkei) for both Halfbeaks in the Karachi Coast of Pakistan, indicating the habitat is still in balance condition with the good combination of prey and predators

Biometric indices and size at first sexual maturity of eight alien fish species from Bangladesh

The biometric indices and size at first sexual maturity of eight alien fish species from several water bodies in Bangladesh were studied for the first time. A total of 273 individuals of eight alien fish species (Barbonymus gonionotus, Clarias gariepinus, Ctenopharyngodon idella, Cyprinus carpio, Hypophthalmichthys molitrix, H. nobilis, Oreochromis niloticus and Pangasianodon hypophthalmus) were collected using traditional fishing gears from June 2014 to May 2015. Among the four condition factors (Allometric condition factor, Fulton’s condition factor, Relative condition factor, and Relative weight) studied, Fulton’s condition factor was the best for assessing the well-being of these alien species in their natural habitat, based on the relationships of condition factors with body weight and total length. The calculated form factor was 0.0270 for B. gonionotus, 0.0077 for C. gariepinus, 0.0119 for C. idella, 0.0194 for C. carpio, 0.0101 for H. molitrix, 0.0092 for H. nobilis, 0.0158 for O. niloticus and 0.0105 for P. hypophthalmus. The size at first sexual maturity was estimated in TL as 12.30 cm for B. gonionotus, 25.53 cm for C. gariepinus, 32.80 cm for C. idella, 18.22 cm for C. carpio, 23.92 cm for H. molitrix, 30.18 cm for H. nobilis, 21.78 cm for O. niloticus, and 21.32 cm for P. hypophthalmus. The present study also calculates form factor and first sexual maturity of these alien species from different water-bodies world over. The findings of this study can be very helpful for sustainable management of these alien species in Bangladesh and similar ecosystems