Length–weight relationships of three freshwater fish species from Rupnaryan and Kangsabati River,West Bengal,India

The length–weight relationships (LWRs) of three freshwater fish species from the Kangsabati and Rupnaryan river in West Bengal, India are presented, namely as Amblypharyngodon microlepis (Bleeker, 1853), Parambassis lala (Hamilton, 1822) and Macrognathus aculeatus (Bloch, 1786). Gill‐nets (mesh sizes with 0.5 cm–4 cm), cast‐nets (up to 1 × 1 cm mesh size with up to 4.0 m² area) and scoop‐nets (0.3 × 0.3 cm and 0.5 × 0.5 cm mesh size) were used from January, 2017 to April, 2018. Sampling was done every 15 days during this period. The value of parameter “b” ranged from 2.751 to 2.895 with highly significant correlations (r² > 0.95).     

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 13 fish species from the Lijiang River,China

The length–weight relationships (LWRs) of 13 species belong to three orders and four families from the Lijiang River, China. Samples were obtained between 2013 April and 2015 January using gillnets (25 × 12 m, mesh size 0.5 cm), trawl nets (50 × 12 m, mesh size 0.5 cm) and fishhooks (0.5 × 0.5 × 10 m, mesh size 0.5 cm mesh). Exponent b varied from 2.639 to 3.549 and r² values varied from .962 to .995.     

Length–weight relationships of nine freshwater fishes from six rivers of the Western Ghats of India

Length–weight relationships (LWRs) were estimated for nine freshwater fish species collected three times using a scoop net (mesh size 0.3–0.5 cm), cast net (mesh size 1–1.5 cm) and gillnet (mesh size 2.5–4.5 cm) from six rivers of the Western Ghats of India during August 2017–October 2018. The b values for LWRs varied from 2.862 to 3.656 (R² > 0.916 and p < 0.0001 for all species).     

Length–weight relationships of three fish species from Bohai Sea,China

Length–weight relationships were determined for three fish species (Cynoglossus macrolepidotus (Bleeker, 1851), Liparis tanakae (Gilbert & Burke, 1912), Zoarces elongatus (Kner, 1868)) from Bohai Sea (38°38′–40°28′N; 119°42′–121°10′E), China. Fish specimens were sampled monthly between May 1982 to May 1983 using pair bottom trawlers (150.5 × 96.5 m, mesh size: 30–200 mm) with a cod end (mesh size: 30 mm), which were towed at a ship's speed of two knots for 1 hr at a maximum depth of about 80 m. Relationships between length and weight were fitted very well for all species (all R² > .90).     

Length–weight relationship of five coral reef fish from the Weizhou Island,China

In the present study, the LWRs investigations were conducted for five fish species from Weizhou Island for four times seasonally during the period from April 2017 to January 2018. Samples were obtained using gillnets (25 × 12 m, mesh size 0.5 cm), trawl nets (50 × 12 m, mesh size 0.5 cm) and fishhooks (0.5 × 0.5 × 10 m, mesh size 0.5 cm mesh). Results indicate that mean LWR parameters b for these five coral reef fish varied from 2.847 to 3.525 and r² values varied from 0.972 to 0.988.     

Length–weight and length–length relationships of four native fish species of the Qinghai‐Tibet Plateau,China

This study presents the length–weight (LWR) and length–length relationships (LLR) of four fish species (Gymnocypris namensis Wu & Ren, 1982; Herzensteinia microcephalus Herzenstein, 1891; Triplophysa stenura Herzenstein, 1888; and Triplophysa brevicauda Herzenstein, 1888) collected from the Qinghai‐Tibet Plateau, China. A total of 291 specimens was collected using electric fishing (12V), gill nets (mesh size: 2 × 2 cm, 3 × 3 cm) and cast nets (mesh size: 2 × 2 cm), in July 1998 and October 2014.     

Length–weight relationships of three small fish species caught in the Yarlung Zangbo River basin,China

Length–weight relationships (LWRs) were determined for three small fish species, Glaridoglanis andersonii (Day, 1870), Glyptosternum maculatum (Regan, 1905) and Pseudecheneis sulcatus (Mc‐Clelland, 1842) from the Yarlung Zangbo River basin, China. A total of 285 specimens were collected from the Yarlung Zangbo River in May and October 2017(frequency of sampling during the study period: once per month).The specimens were caught with fishing gear including drifting gillnets (nets: 10 × 1.0 m; mesh size: 3.0 cm) and shrimp cages (nets: 4.0 × 0.5 × 0.4 m; mesh size: 0.5 cm).     

Length–weight and length–length relationships of three Ambassid fishes from the Ganges River (NW Bangladesh)

Length–weight relationships (LWRs) and length–length relationships (LLRs) are presented for the first time for three Ambassid fish species from the Ganges River, northwestern (NW) Bangladesh. Fish were sampled with traditional fishing gear including cast net (mesh size ranges from 1.0 to 2.0 cm), gill net (mesh size ranges from 1.5 to 2.5 cm), square lift net (mesh size ~ 1.0 cm) and conical and box trap, October 2014 to September 2015. Allometric coefficient (b) values were 3.00 for Chanda nama, 3.10 for Parambassis lala and 3.23 for Parambassis ranga, respectively. Additionally, the LLRs were highly significant with r² ≥ .958. The present observations would be an effective tool for their stock assessment in the Ganges River, NW Bangladesh and surrounding ecosystems.     

Length‐weight relationships for three endemic fish species from the upper reaches of the Yangtze River,southwestern China

Length‐weight relationships (LWRs) were evaluated for three endemic fish species (Sinibrama taeniatus Nichols, 1941; Ancherythroculter nigrocauda Yin & Wu, 1964; and Acrossocheilus monticola Günther, 1888) from the upper reaches of the Yangtze River, southwestern China. Samples were collected using gill nets (25 × 12 m, mesh‐size 2.0 cm) and fishing cages (0.5 × 0.5 × 10 m, mesh‐size 1.0 cm) as well as by electroshock (CWB‐2000 P, 12 V, 250 Hz), from July to September in 2013–2016. Prior to this study, the LWRs for these three species (S. taeniatus, A. nigrocauda and A. monticola) were unknown. In addition, new maximum size for A. nigrocauda and A. monticola were provided.     

Length–weight relationships for 15 fish species from the Three Gorges Reservoir

The length–weight relationships (LWRs) for 15 fish species from the Three Gorges Reservoir (TGR) were described in this paper. Specimens were collected using gill nets (mesh size: 6, 8, 10, 12 cm), cage net (mesh size: 1 cm), benthic fyke net (mesh size: 1 cm), hook longlines (80 m long, 3 barbless hooks per meter line) and electrofishing (power: 1,500 w; distance of electrodes: 1–2 m; water depth: 0.2–1.0 m; water area: 1–2 m²; catch by dip net [mesh size: 0.4 cm]) at four sections of the TGR, monthly in June–August and October–November in 2017 and 2018. The first LWR reference for Zacco acutipinnis (Bleeker, 1871), Discogobio brachyphysallidos Huang, 1989, Squalidus nitens (Günther, 1873), Leptobotia pellegrini Fang, 1936, Sinibotia reevesae (Chang, 1944), Pseudobagrus tenuifurcatus (Nichols, 1931), Pseudobagrus medianalis (Regan, 1904), Liobagrus marginatoides (Wu, 1930), Glyptothorax fokiensis (Rendahl, 1925), and Ctenogobius szechuanensis (Liu, 1940) and new maximum total length for 12 species are provided.     

Length–weight relationships of four fish species from the Nujiang River,China

Length–weight relationships (LWRs) were determined for four fish species (Akrokolioplax bicornis [Wu, 1977], Barbodes wynaadensis [Day, 1873], Glyptothorax cavia [Hamilton, 1822] and Placocheilus cryptonemus [Cui & Li, 1984]) from the Nujiang River, China. Samples were collected from March 2008 to August 2016 (frequency of sampling during the study period: once per year), using various fishing gears (set nets [mesh: 1.5 cm × 2.0 cm], fish cages [0.5 cm mesh], hook, drift gill nets [mesh: 1.0 cm × 2.0 cm × 3.0 cm] and electro fishing). Two new maximum SL were recorded for B. wynaadensis and P. cryptonemus.     

Length–weight relationship of 12 fish species from the Lhasa River and surrounding area in Tibet,China

Presented are the relationship between standard length (SL) and weight (W) for 12 fish species in Tibet, China, representing three families and six genera from the Lhasa River. All fish samples were collected by either electro‐shocker (12 V, 200 Hz), fish cages (mouth opening: 40 × 40 cm², 5 m), or drift gillnets (3 × 1.5 m; mesh‐size: 3 cm to 8 cm) from different areas in the Lhasa River Basin, August and September 2015. Parameter b ranged from 2.88 to 3.29, and all correlation coefficient (r²) values were higher than 0.95. Length–weight relationships (LWRs) for three of the species as well as one maximum length are first reports for FishBase.     

Length‐weight relationships of nine fish species from the Qingjiang River,Yangtze River basin,China

This study presents the first report of length‐weight relationships (LWRs) for five fish species (Parabotia fasciata, Megalobrama mantschuricus, Plagiognathops microlepis, Rhodeus sinensis, Rhodeus fangi) and maximum total lengths for four species from the Qingjiang River, Yangtze River basin, China. Specimens were sampled in six sections along the Qingjiang River over a period of 1 year between April 2016 and March 2017 with gill nets (150 × 10 m; mesh size: 1–14 cm), benthic fyke nets (mouth opening: 12 × 12 cm; 10 m; mesh size: 1 cm) and stationary lift nets (10 × 10 m; mesh size: 0.8 cm).     

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

Length–weight relationships (LWRs) were determined for three fish species (Gymnodiptychus pachycheilus (Herzenstein, 1892), Triplophysa bleekeri (Sauvage & Dabry de Thiersant, 1874) and Triplophysa pseudostenura (He, Zhang & Song, 2012)) from the Yalong River in China. Samples were obtained between March 2009 and July 2013 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). For each species, the sample size, length range, weight range, LWR, 95% confidence intervals of a and b, and coefficient of correlation were determined. Prior to this study, the LWRs for these three species were unknown.     

Length-weight relationships of fish species from the Stung Russei Chrum River basin,Kingdom of Cambodia

This study evaluated the length-weight relationships (LWRs) for three teleost fish species sampled from the Stung Russei Chrum River basin, Kingdom of Cambodia. The fish were collected during two dry seasons (April 2019 and November 2019) and one rainy season (October 2018) using monofilament trammel nets (2–12 cm mesh size), cast net (mesh size 2 cm) and scoop-nets (mesh size with 0.3 cm). Results showed that all fitted regressions were highly significant and the coefficients of determination (r²) were high. This study expanded the value of maximum total length for Cyclocheilichthys apogon and Poropuntius laoensis while reported the wider ranges of total mass for Poropuntius laoensis. Moreover, our present study also provided the novel LWRs records for Hemibagrus filamemtus.     

Length‐weight and length‐length relationships of three small indigenous fishes from the Payra River,southern Bangladesh

Length‐weight relationships (LWRs) and length‐length relationships (LLRs) for three small indigenous fishes (Esomus danrica, Pachypterus atherinoides and Salmostoma bacaila) were reported from the Payra River, southern Bangladesh. Samples were collected using traditional fishing gear including cast net (mesh size ranges from 1.0 to 2.0 cm), seine net (mesh size ranges from 1.5 to 2.5 cm) and square lift net (mesh size ~ 1.0 cm) in August to September 2017. Allometric coefficient (b) values were 2.66 for E. danrica, 3.08 for P. atherinoides and 3.06 for S. bacaila. The LLRs were also highly significant with r² ≥ .956.     

Flow‐injection determination of cysteine in pharmaceuticals based on luminol–persulphate chemiluminescence detection

A flow injection (FI) method is reported for the determination of l‐ cysteine, based on its enhancement on chemiluminescence (CL) emission of luminol oxidized by sodium persulphate in alkaline solution. The calibration graph was linear over the range 1.0 × 10^–9–5.0 × 10^–7 mol/L (r² = 0.9992), with relative standard deviations (RSDs) in the range 1.1–2.3% (n = 4). The limit of detection (3σ blank) was 5.0 × 10^–10 mol/L with a sample throughput of 120/h. The method was applied to pharmaceuticals and the results obtained were in reasonable agreement with the amount labelled. The proposed method was also applied to cysteine in synthetic amino acid mixtures. Calibration graphs of N‐acetylcysteine and glutathione over the range 1.0–50 × 10^–8 and 0.5–7.5 × 10^–7 mol/L were also established (r² = 0.998 and 0.9986) with RSDs in the range 1.0–2.0% (n = 4), and the limits of detection (3σ blank) were 5.0 × 10^–9 and 1.0 × 10^–8 mol/L, respectively. Copyright © 2008 John Wiley & Sons, Ltd.     

Length–weight relationships of seven fish species in the Yangtze River Estuary and its adjacent waters,Eastern China

The length–weight relationships (LWRs) for seven fish species belonging to five families in the Yangtze River Estuary and its adjacent waters are presented. Cynoglossus gracilis, Cynoglossus macrolepidotus, Ctenotrypauchen chinensis, Collichthys niveatus, Ophichthus apicalis and Erisphex potti were collected monthly in 2009 using trammel nets (the size of smaller mesh net was 1.5 m × 15 m × 4 panels with mesh sizes of 2.5, 3.4, 4.3 and 5.8 cm; the size of larger-mesh net was 2.4 m × 30 m × 4 panels with mesh sizes of 5.0, 6.0, 7.0 and 8.0 cm; soaking overnight). Lophiogobius ocellicauda were collected December in 2020 using shrimp trawl nets (mesh size 2.0 cm). The precision of measurement for the fish specimens is 0.1 cm total length and 0.1 g total weight. The estimated ranges of the parameters a and b for the seven fish species were from 0.0001 to 0.0289 and 2.718 to 3.541, respectively. Two new maximum total length were recorded for Ctenotrypauchen chinensis and Ophichthus apicalis.     

Length–weight relationships of six fish species from mangroves of Qinzhou Harbor,Southern China

The length–weight relationships (LWRs) for six species were estimated. Fish were captured in the mangroves of Qinzhou Harbour, China, but also some specimens were purchased from fishermen. The sampling was undertaken monthly between May 2011 and April 2012 using seines (mesh size 5–10 mm; height 4 m; length 400 m) and traps (mesh size 8.5 mm; 35 cm² × 10 m for one unit) at seven sampling sites. Standard length was measured (precision 0.1 cm) and weight determined (precision 0.01 g) after preservation in formaldehyde (10%). Besides the equation parameters a (intercept) and b (slope) we determined also the 95% confidence limits for both parameters as well as the coefficient of correlation.