Length–weight relationships of two cyprinid fish species,Crossocheilus latius (Hamilton, 1822) and Garra gotyla gotyla (Gray, 1830) from the Ganga River Basin,India

This study provides length–weight relationship (LWR) information for two fish species (family Cyprinidae), Crossocheilus latius (Hamilton, 1822) and Garra gotyla gotyla (Gray, 1830), from a tributary of the Ganga River Basin, India. Both species had no previous LWR estimates as per Fishbase 2014.     

Length–weight relationships of Barilius bendelisis (Hamilton, 1807), Barilius shacra (Hamilton, 1822) and Barilius barna (Hamilton, 1822) from Manas River in Assam,India

The present study describes the length–weight relationships (LWRs) for three ornamental hill stream fish species from the Manas River in Assam, India, namely, Barilius bendelisis (Hamilton, 1807), Barilius shacra (Hamilton, 1822), and Barilius barna (Hamilton, 1822). Fishes were collected on a monthly basis from March 2015 to February 2016 with cast nets (270 cm, 1.2 cm) and gillnets (7,500 × 130 cm, 5 cm). This is the first information on LWR data for two of the species.     

Length–weight relationships of Hara hara (Hamilton, 1822), Pangio pangia (Hamilton, 1822) and Setipinna brevifilis (Valenciennes, 1848) from the lower Brahmaputra River,Northeast India

The present study describes the length–weight relationships (LWRs) for Hara hara, Pangio pangia and Setipinna brevifilis from the lower Brahmaputra River in Assam, Northeast India, collected from June 2016 to May 2017, using fishing gears namely cast nets (9′, 1 ⁄ 2″) and gillnets (30 × 0.9 m). No previous data have ever been recorded on LWR for these three species.     

Length‐weight relationships of Barilius barila (Hamilton, 1822), Opsarius tileo (Hamilton, 1822) and Cyprinion semiplotum (McClelland, 1839) collected from Manas River in Assam,India

Length‐weight relationships (LWRs) are presented for three hill stream fish species belonging to the family Cyprinidae namely, Barilius barila (Hamilton, 1822), Opsarius tileo (Hamilton, 1822) and Cyprinion semiplotum (McClelland, 1839). Fishes were collected on a monthly basis from January 2016 to December 2017 with the help of cast net (270 cm length, 1.2 cm mesh size) and gillnet (7,500 cm length × 130 cm depth, 5 cm mesh size) from the Manas river in Assam, India.. A new length record for the FishBase LWR database was observed in B. barila.      

Embryonic development of the threatened freshwater pipefish Microphis deocata (Hamilton, 1822)

The present study provides the first comprehensive embryonic development of the freshwater Syngnathid fish species, Microphis deocata (Hamilton), a Near Threatened pipefish endemic to the Brahmaputra River drainage in Northeast India and Bangladesh. Microphis deocata is a Gastrophori species as the males develop an abdominal brood pouch. Mature individuals were collected and maintained in well-aerated aquaria under controlled conditions to induce natural spawning. The number of eggs within the males' brood pouch ranged from 17 to 22 (for n = 10), measuring 0.7–1.0 mm in diameter. A total of 10 developmental stages could be recognized under four developmental periods namely, early embryogenesis, eye development, snout formation and juvenile. However, sensitivity, and therefore mortality, while handling of this species restricted the study from reporting the exact time intervals for stages following the blastodisc formation ~48 hr post fertilization. A newborn larvae measures ~14 mm and is free-swimming with distinct dorsal fin (with 31–32 rays) and a sector-shaped caudal fin (with 8–9 rays). The study aims to provide baseline information on the embryology of M. deocata in culture condition which will be helpful for future studies on conservation biology, population status and management of this species.     

Length weight relationships of two small indigenous cyprinid fishes,Osteobrama cotio (Hamilton, 1822) and Salmophasia phulo (Hamilton, 1822) from Panchet Reservoir,Damodar River (tributary of River Ganga), India

Length–weight relationships were determined for two small indigenous cyprinid fishes: Osteobrama cotio (Hamilton, 1822) and Salmophasia phulo (Hamilton, 1822) collected from Panchet reservoir, Damodar River, India. About 143 specimens of Osteobrama cotio (5.2–10.4 cm TL) and 113 specimens of Salmophasia phulo (2.9–8.2 cm TL) were collected from November 2014 to June 2016 using gillnets of mesh size ranging from 25 to 120 mm (STR) and dragnets of mesh size 10–20 mm (STR). No previous information on LWRs for these two species from an Indian reservoir was available in the literature.     

Length–weight relationships of five endemic fish species from the lower Yarlung Zangbo River,Tibet, China

The length–weight relationships were estimated for five endemic fishes (Schizothorax curvilabiatus, Schizothorax molesworthi, Garra kempi, Neolissochilus hexagonolepis, Exostoma labiatum) from the Yarlung Zangbo River in Tibet, China. Fishing gear used for sampling included 4 cm mesh gill nets (100 m long × 1.2 m high) and electrofishing, from December 2015 to January 2016. Three of the species have new records of maximum length in FishBase.     

Length–weight relationships of three fish species from Wujiang River,China

Length–weight relationships were determined for three fish species (Pseudogyrinocheilus prochilus Sauvage & Dabry de Thiersant, 1874; Folifer brevifilis Peters, 1881; and Garra imberba Garman, 1912). Samples were collected from the Wujiang River in China, from May to July in 2009–2011 using gillnets (25 × 12 m, mesh size 0.5 cm) and fish cages (0.5 × 0.5 × 10 m, mesh size 0.5 cm mesh). Length–weight relationships for these three fish species were determined for the first time.     

Length–weight relationships of Dermogenys pusilla Kuhl & van Hasselt, 1823 (Zenarchopteridae) and Labeo bata (Hamilton, 1822) (Cyprinidae) from the Ganges River (NW Bangladesh)

Length‐weight relationships (LWRs) were determined for Dermogenys pusilla (n = 75) and Labeo bata (n = 304) from the Ganges River, northwestern Bangladesh, collected between July 2013 and June 2014, using traditional fishing gear (e.g. cast net, square lift net and gill net). Total length (TL) was measured to 0.1 cm and whole body weight (BW) was taken to the nearest 0.1 g for each individual. The TL varied from 6.60 to 16.10 cm for D. pusilla and 7.90–25.20 cm for L. bata. The BW ranged from 1.20 to 10.90 g for D. pusilla and 4.70–167.30 g for L. bata. All LWRs were highly significant (P < 0.001), with all r² values ≥0.976. Moreover, the present study provides a new record of the maximum length (16.10 cm TL) for the D. pusilla female. The present study can assist in the management of these two endangered species in the Ganges River ecosystem.     

Distributional records of Tor mahseer Tor tor (Hamilton, 1822) from Southern India

During exploratory surveys in the tributaries (Penganga and Satnala) of Godavari and (Bheema) Krishna basins, specimens of mahseer were collected. The morpho‐meristic characteristics of these specimens conformed to the taxonomic keys for Tor tor. The mitochondrial COI sequences of these specimens clustered with the T. tor specimens from the River Narmada and were distinct from the other mahseer such as T. khudree and T. mussullah, which are known to exist in the rivers of the region. This confirmed the distribution of T. tor in the rivers of peninsular India and indicated an extended distribution of the known range. The major predominating habitat characteristics of collection areas were cobbles mixed with gravel, and a riparian cover of shrubs and trees. The occurrence of fingerling size specimens in the river suggests that the species has adapted and is likely to have established self‐recruiting populations in these rivers.     

Carcass characteristics of marketable size farmed catla,Catla catla (Hamilton, 1822)

The present study investigates carcass traits of farmed freshwater Catla catla for important information in calculating yield and/or providing data for programming machine/manual handling. For this purpose specimens of C. catla ranging from 1880 to 2150 g were collected from grow‐out culture ponds of the Central Institute of Freshwater Aquaculture, Odisha State, India. Carcass yield, offal yield and carcass cutability were assessed. The percentage of head yield was highest (31.2%) in comparison to other carp species. Gutted yield and final dressed yield of 2 kg market class catla amounted to 85.4 and 54.1%, respectively. The average meat : bone ratio in filleting was reported to be 3 : 9. The middle cut of catla had both the highest total yield percentage and highest meat yield. Dry matter, ether extract and protein percentage was highest in the fore cut followed by the middle and hind cuts.     

Length–weight and length–length relationship of Thryssa purava (Hamilton, 1822), Thryssa polybranchialis Wongratana, 1983 and Thryssa mystax (Bloch & Schneider, 1801) from Chilika lagoon,India

Current study provides basic information on Length–weight relationship (LWR) and length‐length relationship (LLR) of three fish species of genus Thryssa (Clupeiformes: Engraulidae) i.e., Thryssa purava (Hamilton, 1822), Thryssa polybranchialis Wongratana, 1983 and Thryssa mystax (Bloch & Schneider, 1801) from Chilika Lagoon, India. Samples were collected during the monsoon (July) and post‐monsoon (November) seasons in 2016 and during the pre‐monsoon season (May) in 2017, using screen barrier nets (mesh size 8–18 mm) and gill nets (mesh size 14 and 16 mm). The b values were determined from LWRs as 3.026 for Thryssa purava, 3.326 for Thryssa polybranchialis and 3.081 for Thryssa mystax.     

Length‐weight relationship and reproductive parameters of Botia dario (Hamilton, 1822) in Assam,India

The length‐weight relationships, spawning season, sex ratio, size at first maturity and fecundity of Botia dario (Hamilton, 1822), also known as the Bengal loach, were analyzed based on 556 specimens collected from the wetlands of Majuli Island, Assam between June 2012 and May 2013. The sex ratio (M : F) was 1 : 0.68, differing significantly (P < 0.05) from a 1 : 1 ratio. Size at first maturity (L_m50) was estimated as 6.8 cm for males and 7.4 cm for females. Analysis of monthly variations in the gonado‐somatic index (GSI), the monthly proportions of macroscopic gonadal maturity, and the ova diameter suggest a prolonged spawning season of B. dario from May to August, with a peak in July for both males and females (GSI = 15.0 in females; 7.0 in males). Absolute fecundity varied from 2523 to 51 377, with a mean of 18 367 ± 1254 oocytes per ovary. A positive correlation was recorded between total fecundity and body weight (r² = 0.678).     

Length–weight relationships for five fishes in the Nmai Hka River,Myanmar

Length–weight relationships (LWRs) were investigated for five fish species occurring in the Nmai Hka River. Fish were collected monthly from five sites between January and May 2009, using five gill nets in the main river and electrofishing in tributaries. The results of LWRs for Bangana devdevi (Hora, 1936), Garra qiaojiensis Wu & Yao, 1977, Amblypharyngodon atkinsonii (Blyth, 1860), Schizothorax meridionalis (Tsao, 1964) and Mystus pulcher (Chaudhuri, 1911) provide basic data useful in fisheries science. All values of parameter b ranging from 2.89 for Bangana devdevi (Hora, 1936) and 3.47 for Garra qiaojiensis Wu & Yao, 1977(in all cases r² > .951).A new total length has been recorded for Garra qiaojiensis Wu & Yao, 1977 when comparing with records given in the international electronic databank FishBase (Froese & Pauly, 2017).     

Morphological variations among four riverine populations (Bangladesh) of endangered catfish Rita rita (Hamilton, 1822)

The morphological variation of the endangered catfish Rita rita was studied based on meristic, length–weight relationship (LWR), traditional (TRA) and truss (TRU) distance based morphometric analysis of 200 juveniles collected from the Old Brahmaputra, Jamuna, Meghna and Kangsa rivers. Data were subjected to Kruskal–Wallis test for meristic counts, t test for LWR, univariate ANOVA, multivariate discriminant function analysis and canonical analysis (CA) both for TRA and TRU morphometric characters to discriminate the populations. Kruskal–Wallis test denoted that only one (caudal fin rays) out of six meristic counts was significantly (p < .05) variable among the stocks. One sample t test clarified that all parameters of LWR were significantly (p < .05) differentiated in all stocks. Univariate ANOVA revealed significant (p < .001, p < .01, and p < .05) differences among the four stocks in 14 of 15 standardized TRA traits and 17 of 25 TRU distances, respectively. The first discriminant function (DF1) explained 59.4% and 68.0% of total variance, while 30.6% and 23.1% by DF2, 10.0% and 8.9% by DF3 for TRA and TRU features, respectively among the stocks. CA showed a clear separation of the stocks both for TRA and TRU measurements. The overall random assignment of individuals into their original groups was high as 78.5% for TRA and 78.0% for TRU characters, respectively, indicating that all the four stocks are highly divergent from each other. The results exposed existence of four distinct phenotypic stocks of R. rita in the tested rivers.     

Length–weight relationships of four fish species from the MoTuo reach of the Yarlung Zangbo River,southwest China

Length–weight relationships (LWRs) were evaluated for four fish species from the MoTuo reach of the Yarlung Zangbo River, southwest China: Exostoma labiatum (McClelland, 1842), Schizothorax curvilabiatus (Wu & Tsao, 1992), Nemacheilus subfusca (McClelland, 1839), and Garra kempi Hora, 1921. The a values ranged from 0.0094 (Schizothorax curvilabiatus) to 0.0151 (Exostoma labiatum), b values from 2.698 (Exostoma labiatum) to 2.974 (Schizothorax curvilabiatus), and r² values from 0.976 (Nemacheilus subfusca) to 0.995 (Schizothorax curvilabiatus). A total of 427 fish specimens were collected by electrofishing in April 2015, with LWRs previously unknown to FishBase for four of the species. New maximum lengths are recorded in FishBase for three of these species: Schizothorax curvilabiatus, Nemacheilus subfusca, and Garra kempi.     

Length‐weight and length‐length relationships of Balitora brucei Gray, 1830 and Psilorhynchus balitora (Hamilton, 1822) from the Ranganadi river of Assam,India

The study describes length‐weight relationships (LWRs) and length‐length relationships (LLRs) for two species of fishes, namely Balitora brucei Gray, 1830 and Psilorhynchus balitora (Hamilton, 1822) collected from Ranganadi river in Lakhimpur district of Assam, India for which no LWRs and LLRs are available. While sampling monthly between April 2012 and July 2016, a total of 987 specimens were collected (B. brucei = 427, and P. balitora = 560). Cast nets were used (2 ‐ 10 mm mesh sizes; 2–2.5 m length). The values of the parameter slope (b) in the LWR were determined as 3.194 (male = 3.047 and female = 3.224) for B. brucei and 3.490 (male = 3.480 and female = 3.502) for P. balitora. Present investigation reports new maximum total length for both the fishes.     

Length‐weight and length‐length relationships of two gobiid fishes Eleotris fusca (Forster, 1801) and Odontamblyopus rubicundus (Hamilton, 1822) from the Payra River,southern Bangladesh

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.