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The present study was conducted in the coastal pond ecosystems of Pakistan to evaluate the optimum salinity level for the best growth performance of a commercial shrimp, Litopenaeus vannamei. Total of 6 lac seed was randomly distributed in three ponds with an average initial body weight of 0.1±0.01 g. The shrimps were cultivated in three different ponds demarcated as pond 1, pond 2 and pond 3 with salinity levels of 8 ppt, 22 ppt and 42 ppt, respectively for 105 days. The pacific white shrimp were fed with 35.0% crude protein diet with feeding frequency of 4 and initially feeding rate of 10% biomass per day. The feeding rate adjusted according to shrimp biomass on a weekly basis. Final weight, specific growth rate, average daily weight gain, viscerosomatic index, hepatosomatic index and survival rates were found optimum at salinity level of 22 ppt compared with salinity levels of 8 ppt and 42 ppt (p <0.05). FCR was better at 22 ppt salinity compared with two other tested salinity levels (p <0.05). The 22 ppt salinity level resulted in optimum growth of L. vannamei which might be due to improved osmoregulation. Feeding frequency of 4, protein 35% and salinity of 22 ppt were found suitable factors for the growth performance of L. vannamei reared in aquaculture system. [ABSTRACT FROM AUTHOR]

This research work affirms the morphometric characters and meristic counts of Channa punctata (Bloch, 1793) in a wetland ecosystem (Gajner Beel) from the northwestern Bangladesh. A sum of 307 specimens of C. punctata were sampled intermittently from the Gajner Beel during July 2017 to December 2018, using different established fishing gears (cast net, gill net and square lift net with mesh size ranges: 1.50-2.50 cm, 1.50-2.00 cm, & ~2.00 cm, respectively). Fin rays were counted by a magnifying glass. Seven diverse morphometric lengths were assessed and BW (body weight) was weighted for each specimen. The fin formula was: dorsal, D. 30-32; pectoral, P1. 15-17; pelvic, P2.5; anal, A. 19-21; and caudal, C. (ii -iv/12-14). Minimum and maximum sizes were 5.80 and 23.00 cm in total length (TL), whereas BWs were1.96 and 126.90 g, respectively. All length-weight relationships (LWRs) were greatly significant (p < 0.001) with r² ≥ 0.986. Based on r² value, BW = 0.0112*(TL)2.98 was the most appropriate model among seven equations. Besides, based on r² values, length-length relationships (LLRs) by TL vs. SL was the finest model among six equations. These findings will help for species identification and further stock/ biomass estimation of C. punctata in the Gajner Beel or connected ecosystems. [ABSTRACT FROM AUTHOR]

The current study provide the baseline information on the temporal (monthly) variations of condition through multiple functions (allometric, KA; Fulton's, KF; relative, KR) and prey-predator status through relative weight (WR) for Eutropiichthys vacha (Hamilton, 1822) from the Ganges River, northwestern Bangladesh over one year. The smallest individuals were 6.5 and 6.2 cm in TL, whereas the largest were 19.9 and 20.6 cm in TL for males and females, respectively. No significant differences were observed in the length frequency distribution, LFDs (p = 0.8152) for both sexes. KF was significantly correlated with TL for both sexes (p < 0.001) and KF was treated as the best condition factor therefore, well-being of E. vachaa. There was no significant correlation among TL vs KA, TL vs KR and TL vs WR for males and females, respectively. But BW showed highly significant correlations with all condition factors, i.e., BW vs KA; BW vs KF; BW vs KR, and BW vs WR (p < 0.001) for both sexes. Additionally, WR revealed no significant dissimilarities from 100 for males (p = 0.432) unlike females (p = 0.023), based on Wilcoxon signed-rank tests, suggesting that habitat was more suitable for males than females for food availability relative to predator presence. Moreover, this study assessed for the first time the effect of temperature and rainfall on monthly KF for E. vacha in the Ganges River. The Pearson correlation test found no significant relation between temperature and KF (r = 0.2226, p = 0.4868 for males; r = 0.2172, p = 0.4977 for females), but significant correlations were found between rainfall and KF (r = 0.6357, p = 0.0263 for males and r = 0.6983, p = 0.0115 for females). [ABSTRACT FROM AUTHOR]

Some aspects of reproductive biology of Pethia ticto (Hamilton, 1822) from the Gorai River of southwestern ( SW) Bangladesh were investigated by regular monthly samples for a period of one year during July 2010 to June 2011. A sum of 1200 specimens (male = 454 and female = 746) were collected using cast net, lift net and conical trap. Total length ( TL) and Body weight ( BW) were measured with slide caliper and digital balance, respectively for each individual. Based on gonadosomatic index ( GSI), modified gonadosomatic index ( MGSI) and Dobriyal index ( DI) first sexual maturity was 4.30 cm TL for male and 4.80 cm TL for female. Also, on the basis of higher values of GSI, MGSI and DI spawning season was ranged from April to September for P. ticto in the Gorai River ecosystem. The fecundity was ranged from 2230-8450 with a mean value of 4779 ± 1578. In addition, there was a significant relationship between total length and fecundity ( r 2 = .931, p < .001); body weight and fecundity ( r 2 = .943, p < .001). Therefore, the findings of this study would be very effective for sustainable management of this threatened species in the Gorai River and surrounding ecosystem. [ABSTRACT FROM AUTHOR]

This study focused on the length-weight and length-length relationships of five Mystus species from Bangladesh. A sum of 398 individuals ( Mystus bleekeri = 47, Mystus cavasius = 171, Mystus gulio = 59, Mystus tengra = 65, and Mystus vittatus = 56) was collected from the Ganges and Rupsha rivers, Bangladesh. Fishes were caught by gill net (mesh sizes: 2.0-4.0 cm) and cast net (mesh sizes: 1.5-3.0 cm) from July 2014 to June 2015. Total length ( TL), fork length ( FL) and standard length ( SL) were measured to 0.1 cm, while whole body weight ( W) was taken to the nearest 0.1 g for each individual. The TL ranged from 6.0-13.5 cm for M. bleekeri, 5.0-15.0 cm for M. cavasius, 7.4-17.2 cm for M. gulio, 4.6-11.6 cm for M. tengra and 5.5-12.3 cm for M. vittatus. The W varied from 3.0-18.2 g for M. bleekeri, 1.3-30.4 g for M. cavasius, 6.1-62.2 g for M. gulio, 1.7-15.1 g for M. tengra and 2.7-19.2 g for M. vittatus. All LWRs were highly significant ( p < .001), with all r 2 values ≥.950. The LLRs were also highly significant ( p < .001), with all r 2 ≥.980. This study provides information on LWRs and LLRs for M. gulio and M. tengra for the first time. The results of this study can be very effective for stock assessment of Mystus species in the Ganges and Rupsha rivers as well as in the surrounding ecosystems. [ABSTRACT FROM AUTHOR]

Summary: The present study provides the estimates of length‐weight relationships (LWRs) and length‐length relationships (LLRs) of two gobiid fishes Eleotris fusca and Odontamblyopus rubicundus from the Payra River, southern Bangladesh. Fish samples were collected from the set bagnet (mesh size <2 mm) fishers of the Payra River in July 2016. Allometric coefficient (b) values were 2.95 for E. fusca and 2.76 for O. rubicundus. Additionally, the LLRs were highly significant with r2 ≥ .955. While the estimate of the LWR for O. rubicundus includes a substantial larger sample size and thus provides a more reliable LWR than the one published so far, the LWR for E. fusca must be considered as tentative because the sample includes only juveniles for a fish that reaches a maximum standard length more than three times as much. Additional studies are needed to further improve our LWR knowledge base for these fish species. [ABSTRACT FROM AUTHOR]

Data and information are needed to avert the alarming decline and initiate conservation measures for three threatened fishes, Labeo boga (Hamilton, 1822), Nandus nandus (Hamilton, 1822) and Puntius ticto (Hamilton, 1822), from the Ganges River and surrounding ecosystems. These fishes are decreasing rapidly due to high fishing pressures as well as environmental degradation. This study furnishes the length-weight relationships ( LWRs), length-length relationships ( LLRs) and form factor ( a3.0) of these three threatened species from the Ganges River, northwestern Bangladesh. A total of 773 specimens from the three species and two families used for this study were caught by traditional fishing gear between April 2011 and March 2012. The analysis of covariance ( ancova) revealed significant differences between the sexes in LWRs for L. boga (P < 0.001), but not with the remaining species (P > 0.05). Furthermore, the LLRs were highly correlated ( r 2 > 0.983; P < 0.001), and ancova analyses additionally indicated that LLRs did not differ between sexes (P > 0.05). The calculated form factor ( a3.0) was 0.0111, 0.0159 and 0.0129 for L. boga, N. nandus and P. ticto, respectively. This study presents the first references on LWRs, LLRs and form factor for these three threatened species in Bangladesh. The results would be useful for further studies on the population assessment and sustainable conservation of the limited stocks in the Ganges River ecosystem. [ABSTRACT FROM AUTHOR]

The present study describes the size at first sexual maturity, fecundity, length-weight (LWRs) and length-length relationships (LLRs) of the pool barb, Puntius sophore, using data obtained from different geographical locations in Bangladesh. A total of 905 specimens were caught by traditional fishing gear from March 2010 to February 2011. Additionally, a total of 121 females were collected from a commercial catch of the Padma River during June-July 2011 to estimate size at first maturity and to determine fecundity. Total length (TL), fork length (FL) and standard length (SL) were measured with digital slide calipers. Individual body weights (BW) were determined for all specimens, and gonad weights (GW) from 121 females were weighed to an accuracy of 0.001 g. The female gonadosomatic index (GSI) was calculated as [GSI (%) = (GW/BW) × 100]. Female size at first maturity was estimated using GSI and TL as indicators, and estimated as 5.00 cm TL in the Padma River. Specimens larger than 5.00 cm TL were used to determine fecundity. Mean total fecundity was 5300 ± 2700, ranging from 1580 to 16590. A positive exponential correlation was recorded between total fecundity and total length ( r2 = 0.421). Relative fecundity ranged from 466 to 4036 (mean 1100 ± 580) in the Padma River. The LWR of pooled data for sexes combined was estimated as BW = 0.0155 TL2.98 as ancova revealed no significant differences in LWRs between rivers (P > 0.05). All LLRs were highly correlated ( r2 > 0.983; P < 0.001), and ancova analyses further indicated that LLRs did not differ between rivers (P > 0.05). These results will help in further studies on the population assessment of the species. [ABSTRACT FROM AUTHOR]

This study was conducted to assess the aquaculture potential of the freshwater prawn Macrobrachium rosenbergii (de Man, 1879) with the Indian major carps (Catla, Catla catla; Rui, Labeo rohita and Mrigal, Cirrhinus mrigala) and silver carp, Hypophthalmichthys molitrix in northwestern Bangladesh. Further, the effect of the culture system on overall production and economic feasibility was evaluated. A 3×2 (treatment×replicate) experimental setup was conducted using six earthen ponds measuring 100 m2 each for a culture period of six months from September, 2007 to February, 2008. The treatments were as follows: T1 was stocked with only carps (catla, rohu, mrigal and silver) at the 3000 (catla), 2000 (ruhu), 3000 (mrigal) and 2000 (silver) ha-1; T2 and T3 were stocked with catla and silver carp were 3000 and 2000 ha-1, respectively; and additionally M. rosenbergii (juvenile) was stocked at 15000 and 20000 ha-1 in T2 and T3, respectively. All the ponds were subjected to the same fertilization treatment. Fish were fed twice per day at a rate of 5-12% of the prawn and fish body weight. The net weight gain of catla and silver carp were 69.08±11.63 and 108.67±15.00 g in T1, 61.76±12.58 and 98.80±17.05 g in T2, while 58.11±12.51 and 93.09±14.84 g in T3, respectively. The mean individual weight of harvested prawn was significantly higher in T2 (14.61±02.06 g) than T3 (14.04±01.83 g) (P<0.05). Also the survival rate of prawn was higher in T2 (74.15%) than T3 (69.25%) (P<0.05). The net production of prawn was higher in T3 (1141.28±46.35 kg ha-1) than T2 (964.54±25.53 kg ha-1), but the specific growth rate was significantly higher in T2 (2.07%) than T3 (1.99%) (P<0.05). Higher profit was obtained in T3 (35682.18 Tk ha-1) than T1 (8537.53 Tk ha-1) and T2 (30801.56 Tk ha-1); however, cost-benefit ratio (CBR) was significantly higher in T2 (3.19) where stocking densities of prawn was 15000 ha-1 than T1 (2.92) and T3 (2.47). The results of this experiment indicate that the polyculture of the freshwater prawn with the Indian major and Chinese carp present a more profitable venture which is more economically feasible than the monoculture of the freshwater prawn. [ABSTRACT FROM AUTHOR]

Aquaculture is the fastest-growing food-producing sector in the World and has exhibited continuous improving in total production throughout the recent decades. A carp polyculture experiment was carried out to evaluate the growth performance of major carps in semi-intensive fish culture system. Two earthen ponds located at Kadirganj of Boalia thana under Rajshahi district of Bangladesh were selected to study the effect of fertilizer (organic as cowdung and in-organic as triple super phosphate) in supplemented ponds on the growth of carps. Pond -01 was fertilized with cowdung and TSP at the rate of 1728 and 20 kg/h respectively, at 10-day intervals. Pond -02 was without fertilizer. Each pond was stocked with 30% Labeo rohita, 20% Catla catla, 15% Cirrhinus mrigala, 15% Hypophthalmichthys molitrix, and 20% Cyprinus carpio with a total stocking density of 10000/ha. Both ponds were supplemented with mustard oil cake, rice bran and maize bran at the rate of 2.5 kg/ha for each, given for a period of six months as daily basis. The net fish production was found to be 2605 and 1795 kg/ha/year in pond -01 and pond -02, respectively. The results showed that fish production was significantly higher in pond -01 than pond -02 (P<0.05). Pond -01 showed 1.45 times greater fish production than that of pond -02. The results of this study provided invaluable information for the sustainable aquaculture, as well as providing an important baseline for future studies within Bangladesh and surrounding developing countries. [ABSTRACT FROM AUTHOR]

Summary The small indigenous species, namely Ailiichthys punctata (Day, 1871), Botia lohachata (Chaudhuri, 1912), Chanda nama (Hamilton, 1822), Laubuca laubuca (Hamilton, 1822) and Mystus cavasius (Hamilton, 1822), comprise an important component of riverine fisheries of Bangladesh. This study describes the length-weight relationships (LWRs) and length-length relationships (LLRs) of five threatened fishes from the Jamuna River, a distributary of the Brahmaputra River in northern Bangladesh. A total of 919 specimens from five species in five families used for this study were caught by traditional fishing gear, March 2010 through February 2011. The allometric coefficient ( b) of the LWRs indicated negative allometric growth in A. punctata, B. lohachata, and C. nama ( b < 3.00), but positive allometric growth in L. laubuca and M. cavasius ( b > 3.00). Furthermore, the LLRs were highly correlated ( r 2 > 0.978; P < 0.001). This study presents the first reference on LWRs and LLRs for these threatened species in Bangladesh. The results would be useful for sustainable management and conservation of the limited stocks in the Brahmaputra River ecosystem. [ABSTRACT FROM AUTHOR]

The article discusses the first record of the South American sailfin catfish Pterygoplichthys multiradiatus in Bangladesh. It is noted that Pterygoplichthys multiradiatus is native to the Orinoco River system in South America, which has been introduced in several regions which include the Philippines, Puerto Rico and Hawaii. It is highlighted that its presence in Bangladesh could be attributed to this pathway or to escapes from aquaculture farms where several cyprinid species are cultured with catfishes.