Length–weight relationships of some fish from the Ganga River,India

Length–weight relationships (LWRs) were determined for seven riverine fish species from the river Ganga, India. Specimens were collected on a bi‐monthly basis from April 2017 to December 2018 using gill nets (mesh size 22–34 mm), cast nets (mesh size 16 mm) and bag nets (mesh size 14–22 mm). Total length was measured to the nearest 0.1 cm using a digital caliper and weight was recorded to the nearest 0.01 g on an electronic balance. From estimated length–weight relationships, the values for parameter “a” ranged from 0.004 (Bregmaceros mcclellandi and Setipinna tenuifilis) to 0.014 (Brachirus pan). Likewise, the values for the parameter “b” of the equation ranged from 2.958 (Bagarius bagarius) to 3.124 (Bregmaceros mcclellandi) and r² from 0.978 (Gonialosa manmina) to 0.996 (Brachirus pan).     

Length–weight relationships of four indigenous fish species from Brahmaputra River,Assam, India

The present study was undertaken with the objective to estimate the length‐weight Relationships (LWRs) for four species collected from the Brahmaputra River, Assam, India. The fish samples were collected quarterly from different sampling sites using gill net (mesh size ranges 1–1.5 cm, locally called Mola lungi jal), cast net (mesh size ranges 1.0–2.0 cm, locally called Kevalijal) and triangular dip nets (mesh size ranges 0.75–1.25 cm locally called khorajal) during the time period between May, 2016 to April, 2018 (2 years). The b value of the LWR ranged from 3.028 (for Parambasis lala) to 3.196 (for Psilorynchus balitora). In this study the relationship between length‐weight were highly correlated (p < 0.05).     

Length–weight relationships of three Gobiidae species from the Rupsha River in southwestern Bangladesh

This study reports the length–weight relationships (LWRs) of three Gobiidae fish species (Acentrogobius viridipunctatus, Apocryptes bato, and Odontamblyopus rubicundus) from the Rupsha River, southwestern Bangladesh. A total of 388 individuals were sampled using cast nets (mesh size ranges from 1.5 to 3.0 cm), gill nets (mesh size ranges from 2.0 to 3.0 cm) and square lift nets (mesh size ~1.5 cm) from December 2014 to November 2015. Allometric coefficient (b) values were 3.23 for A. viridipunctatus, 2.70 for A. bato, and 2.67 for O. rubicundus, respectively. The first LWRs records for these three Gobiidae species, they can be used online for FishBase as well as in future studies.     

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 for four fish species from lower stretch of River Ganga,India

Length‐weight relationships (LWRs) for four fish species from the River Ganga (India) is presented. Sampling was conducted in the lower stretch of the river (Buxar: 25°33′43.90″N and 83°56′3.10″E to Freserganj: 21°35′40.58″N and 88°15′28.92″E) on tri‐monthly basis from September 2016 to December 2017. Specimens were caught in gill nets (mesh, 18–68 mm), cast nets (mesh, 12–14 mm), seine nets (mesh, 12–14 mm) and various traditional traps those were put over night and lifted in early morning. Total length and wet body weight of fish were measured to the nearest 0.1 cm and 0.01 g by a digital caliper and electronic balance respectively. From LWRs, the estimated b values were found to be 2.88 (Pisodonophis boro) to 3.17 (Gagata sexualis) whereas a value ranged from 0.001 (Pisodonophis boro) to 0.009 (Botia lohachata). As per FishBase, the species Gagata sexualis and Botia lohachata had new TLmax reported for LWR estimation.     

Length‐weight relationship of two cichlid fish species,Etroplus suratensis (Bloch, 1790) and Etroplus maculatus (Bloch, 1795) from Lake Vembanad,Kerala, India

The present study describes the length–weight relationships (LWRs) of two cichlid fish species, Etroplus suratensis (Bloch, 1790) and Etroplus maculatus (Bloch, 1795) collected from Vembanad Lake, Kerala, India during the period June 2012 to May 2013 using gill nets with various mesh sizes (3.5–9 cm) and cast nets with a 1.5 cm mesh size. The values of parameters b in the LWR equation were estimated as 2.67 for E. suratensis and 2.72 for E. maculatus, respectively.     

Length–weight relationships of three fish species from the Arial Khan River,an outlet of the river Padma,Bangladesh

The present study narrated the length–weight relationships (LWRs) of three fish species Salmophasia sardinella (Valenciennes, 1844), Amblypharyngodon microlepis (Bleeker, 1853) and Macrognathus aral (Bloch & Scheider, 1801) from the Arial Khan River, a south‐eastward outlet of the river Padma, Bangladesh. Fish samples were collected monthly basis from fishermen who used cast nets (mesh size <0.5 cm) and set bag nets (mesh size 0.5 cm) for catching fish species from January to December, 2016. The growth coefficient b in LWRs were 3.004, 3.001 and 2.936 for M. aral, S. sardinella and A. microlepis, respectively.     

Length-weight relationships of four fish species from the Hei River in northwest China

Length-weight relationships (LWRs) were assessed from four fish species in Hei River in northwest China. All specimens were collected using (fishing1 km along the river and 3 meters along the river bank) and netting (gill nets, nets: 30 × 1.2 m; mesh size: 3 × 3 cm) and shrimp cages (nets: 20.0 × 0.5 × 0.4m; mesh size: 0.5 cm) seasonally from April 2019 to October 2020. The gill nets and shrimp cages were soaked in water in the afternoon and pulled in around 10 a.m. the next day after an overnight stay. These specimens were measured for total length (L, 0.1 cm) and body weight (W, 0.1 g) while the specimens were fresh. The parameters for the LWRs were estimated with the basic statistical analyses. The study provided the new maximum total length for Gymnocypris chilianensis (21.0 cm) and Triplophysa tenuis (17.0 cm).     

Length‐weight relationships of three species in northern China

Length‐weight relationships were estimated for three species (Triplophysa microphysa, Triplophysa zamegacephala and Gobio coriparoides) belonging to two families and two genera from northern China. Specimens were collected using trap nets (mesh size 1 cm) in May, June and December 2017, and March 2018. Total length (TL) for each individual was determined to the nearest 0.1 cm by digital slide caliper and each body weight (BW) to an accuracy of 0.1 g using digital balance. The b‐values for LWRs varied from 2.583 to 2.876 (r² > 0.979). This biometric data and their relationships are relevant to the management and conservation for local fishes and fisheries.     

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 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 for nine fishes in the Nujiang River,Southwest of China

Length‐weight relationships (LWRs) were determined for nine fish species occurring in the Nujiang River. Fish were collected using gill nets, including two nets of 1.0 m depth (100 m long; mesh size 0.5 cm), two nets of 1.0 m depth (150 m long; mesh size 2.0 cm) and two nets reaching 1.5 m depth (mesh size 6.0 cm). Gill nets were set over night including different habitats (riffles and pools, vegetated and non vegetated zones) from four sections in July of the following 2 years: 2004 and 2008. The LWRs presented here include for all nine studied species (Pseudexostoma brachysoma Chu, 1979, Creteuchiloglanis gongshanensis [Chu, 1981], Glyptothorax zanaensis Wu, He & Chu, 1981, Glyptothorax dorsalis Vinciguerra, 1890, and Glyptothorax trilineatus Blyth, 1860, Schizothorax gongshanensis Tsao, 1964, Schizothorax meridionalis Tsao, 1964, Placocheilus cryptonemus Cui & Li, 1984, and Schistura longa [Zhu, 1982]), and new maximum standard length of four species not yet reported in the literature.     

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 relationships of four fish species from the lower reaches of the Nujiang River and its tributaries in China

As one of the largest Southeast Asian rivers, flowing through China, Myanmar, and Thailand, the Nujiang (Salween) River contains a unique and rich diversity of fish species. In the present study, we investigated the length–weight relationships (LWRs) of four fish species (Pteronemacheilus meridionalis, Devario shanensis, Exostoma gaoligongense, and Glyptothorax granosus) collected from the lower reaches of the Nujiang River and its tributaries (24.175N~25.842N, 98.861E~98.903E), including the Mengboluo, Kungong, Luomingba and Laowo rivers in southwest China. Specimens were collected by using drift gill nets (100 m length × 1.5 m depth or 3 m depth, mesh-size: 1 cm-5 cm), cast nets (6.5 m, mouth opening: 35 × 45 cm², mesh-size: 4 mm) , and an electric shocker apparatus (12 V, 200 Hz) from different regions in the Nujiang River basin in September and October 2019 and June and September 2020. Before the collected fishes were placed in formalin, standard length (SL) and net weight (W) were measured respectively to the nearest 0.1 cm and 0.1g, respectively. Based on searches of the FishBase database and other relevant scientific literature, this study provides a new record of maximum size for P. meridionalis and LWRs for the four fish species.     

Length–weight relationships of five fish species from the Hongshui River,China

The length–weight relationships (LWRs) of five Chinese endemic fish species caught by cast nets (mesh size 1 cm) and gillnets (mesh size 4 cm) in the Hongshui River in June and July 2011 and October to November 2012 were determined. These are the first LWRs records for the five little‐known species.     

Length‐weight relationships of five fish species from the Hongshui River,China

The length‐weight relationships (LWRs) were determined for five Chinese endemic fish species caught by electrofishing, cast nets (mesh size 1 cm) and gillnets (mesh size 4 cm) in the Hongshui River during June and July 2011 and October to November 2012. These are the first LWRs records for these five little‐known species.     

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 six indigenous fish species from the River Cauvery and its estuary,India

The present study estimated length–weight relationships (LWRs) for six indigenous fish species (Barilius gatensis, Salmostoma acinaces, S. boopis, Puntius amphibius, Hemibagrus punctatus and Ambassis miops) based on specimens collected from River Cauvery (including estuary) during July 2017–January 2020. The sampling surveys were carried out in three distinct sampling seasons, viz., the pre-monsoon (March–May), the monsoon (July–October) and the post-monsoon (November–February). Majority of the fish specimens dealt in the study were collected from multi-meshed monofilament gill nets (mesh sizes 18, 30, 45, 60, 90, 110, 120 and 150 mm) operated by local fishers. For those sites situated in the protected areas, sampling was carried out by cast nets with prior permission from the local administration and the collected fishes were released back into river after length–weight measurements. The length measurements were noted as total length (TL) measured to the nearest 0.1 cm by using a digital Vernier caliper. A digital balance was used for weight measurements with an accuracy of 0.01 g. The study recorded a new maximum length of 48 cm for H. punctatus. The LWR data generated from the present study are significant for proper assessment of the stock status and their management, if collected together with other essential biological and physical parameters.     

Length–weight and length–length relationships of three fish species from the Heihe River,northwest China

Length‐weight (LWRs) and length–length (LLRs) relationships are reported for three fish species belonging to two families and two genera from the Heihe River, northwest China. Fish samples were collected using trap nets (mesh size 1 cm) in May and December of 2016, and April and October 2017. Standard length (SL) and total length (TL) for each individual were measured to the nearest 0.1 cm by digital slide caliper and each body weight (BW) was measured to an accuracy of 0.1 g using digital balance. The b‐values for LWRs varied from 2.580 to 3.164 (r² > .956). The results further indicated that the LLRs were highly correlated (r² > .991; p < .01). This study presents the first references on LWRs for Gymnocypris chilianensis and Triplophysa hsutschouensis, and LLRs for G. chilianensis, Triplophysa leptosoma and T. hsutschouensis. This biometric data and their relationships are relevant to the management and conservation of local fishes and fisheries.     

Length‐weight relationship of three fish species from the Poyang Lake,China

The paper reports the length–weight relationships of 3 species from the Poyang Lake, the largest freshwater lake freely connect to the Yangtze River, China. A total of 1,207 specimens were collected seasonally (January, April, September and November, 2010) using various types of fishing gear nets (mesh size: 1–12 cm) and stationary lift nets (mesh size: 0.7–4.4 cm). For each species, the sample size, length range, weight range, LWR, 95% confidence intervals of a and b, and coefficient of correlation were determined. Length‐weight relationships for 1 species were unknown to FishBase, and new maximum lengths are recorded for 2 species.