Length–weight relationships for two loach species,Sinibotia superciliaris (Günther, 1892) and Sinibotia reevesae (Chang, 1944) collected from the Tuojiang River,China

Length–weight relationships were determined for two loach species, Sinibotia superciliaris (Günther, 1892) and Sinibotia reevesae (Chang, 1944). Samples were collected with gill nets (30 × 15 m, mesh‐size 1.5 cm) and fish cages (mesh‐size 0.5 cm) as well as by electroshock (CWB‐2000 P, 12 V, 250 HZ) between May 2013 and June 2015 from the Tuojiang River in southwest China. It is believed that the size range covered is close to a commonly known size range of each species. The length–weight relationship values of b were determined as 3.105 for S. superciliaris and 3.381 for S. reevesae. The data will be helpful in further research regarding these species in the upper Yangtze River Basin.     

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 relationship of two mudskippers (Gobiidae: Oxudercinae) Oxuderces dentatus (Eydoux & Souleyet, 1850) and Scartelaos histophorus (Valenciennes, 1837) from Dhamara estuary,Odhisa, India

Oxuderces dentatus and Scartelaos histophorus species were collected seasonally from the Dhamara estuary (Odhisa, India) using scoop nets, cast nets as well as by hand for a period of 1 year (January 2015–December 2015). Length–weight relationships were estimated. Total lengths (TL) for O. dentatus ranged from 42 to 80 mm, and from 58 to 122 mm for S. histophorus. Similarly, total weights of O. dentatus and S. histophorus ranged from 2.5–10.7 g to 7.7–26.5 g, respectively. The ‘b’ values estimated for O. dentatus (2.718) and S. histophorus (2.689) were below 3. The condition factors of O. dentatus and S. histophorus were minimum in summer and maximum post‐monsoon.     

Length–weight and length–length relationships of three fish species from the Yarlung Zangbo River in Tibet,China

Length–weight relationships and length–length were evaluated for three fish species (Schizopygopsis younghusbandi Regan, 1905; Ptychobarbus dipogon Regan, 1905 and Oxygymnocypris stewartii Lloyd, 1908) from the Yarlung Zangbo River in Tibet. Specimens were captured monthly using floating gillnets (mesh size 7.5 cm), bottom gillnets (mesh size 6.5 cm), and trap nets (mesh size 1.5 mm) from August 2008 to August 2009, March to August 2012, and March to April 2013. Regression coefficient (b) values of length–weight relationships (LWRs) ranged from 3.045 for P. dipogon to 3.193 for O. stewartii, whereas the a values ranged from 0.0040 to 0.0168 for O. stewartii and P. dipogon, respectively.     

Length–weight relationships of four marine fish species in Motaf fishing grounds,southern waters of Bushehr (the north of the Persian Gulf,Iran)

This study presents the length–weight relationships (LWRs) of four caught fish, including Drepane punctata (Linnaeus, 1758), Alectis indica (Rüppell, 1830), Argyrops spinifer (Forsskål, 1775), and Saurida tumbil (Bloch, 1795). During 27 tows, the fish specimens were captured by Cutlassfish trawl net, with 80 mm mesh size in the cod‐end, from March 2015 to April 2016. The fishing operation was conducted at depths more than 50 m in southern waters of Bushehr (the northern Persian Gulf). The estimated b values were as follow: 3.17 for D. punctata, 2.59 for Alectis indica, 2.56 for A. spinifer, and 3.26 for S. tumbil. In the present study, new maximum total lengths for D. punctata (15.2–43.5 cm), A. indica (21–69.5 cm), and A. spinifer (15.3–66.5 cm) were reported in comparison with previous researches.     

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 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.     

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.      

Length‐weight relationship of Thryssa malabarica (Bloch, 1795) and Thryssa dayi Wongratana, 1983 from Kerala,southwest coast of India

The present study reports the length‐weight relationships (LWRs) of two clupeoid fish species, Thryssa malabarica (Bloch, 1795) and Thryssa dayi Wongratana, 1983 from Kerala waters, southwest coast of India during the period October 2015 to September 2016. Altogether 88 specimens of T. malabarica and 97 T. dayi were collected on weekly basis from gill nets (mesh size, 2.6–5.0 cm) and ring seines (mesh size, 0.8–2.6 cm) during the period. The value of parameter b in the equation of LWRs was estimated as 3.237 and 3.248 for T. malabarica and T. dayi respectively.     

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 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 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 for three freshwater fish species from the Pengxi River (a tributary of the Yangtze River,China)

This study determined the length–weight relationships of three freshwater fish species [Culter oxycephaloides (Kreyenberg & Pappenheim, 1908), Squalidus argentatus (Sauvage & Dabry de Thiersant, 1874), Rhodeus sinensis (Günther, 1868)] from Pengxi River, a tributariy of Yangtze River of China. Fish were collected during 2016 using drift gill nets (mesh size 1, 2 and 3 cm) and cage net (0.5 cm mesh size). For Culter oxycephaloides had no previous length–weight estimates were reported in the science literature. For Squalidus argentatus the present estimate includes a new maximum total length while for Rhodeus sinensis our study confirms the only existing LWR estimate quite well.     

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 three indigenous fish species from National Nature Reserve for Rare and Endemic Fishes of the upper Yangtze River,China

Length‐weight relationships (LWRs) were estimated for three small indigenous fish species, (Sinogastromyzon szechuanensis, Sinogastromyzon sichangensis and Sinocrossocheilus labiatus) in the upper Yangtze River, China. Samples were collected using three types of local traditional fishing gears, including gill nets (mesh size: 1 cm), fish cages (mesh size: 0.5 cm), and electrofishing techniques (CWB‐2000 P, 12V, 250 Hz), in April, July and October 2013 and 2014, and April and October 2016. The sample size for each species were gathered separately, with 100 for S. szechuanensis, 381 for S. sichangensis and 49 for S. labiatus from National Nature Reserve for rare and endemic fishes of the upper Yangtze River, China. The length‐weight relationship parameter values of b were calculated as 2.986 for S. szechuanensis (b: 2.854–3.118), and 3.284 for S. sichangensis (b: 3.209–3.359) and 3.119 for S. labiatus (b: 2.911–3.326). The primary data will be meaningful for further research about sustainable development and scientific management of fishery resources of the upper Yangtze River.     

Length‐weight relationship of two Ambassid fish species,Parambassis dayi (Bleeker, 1874) and Parambassis thomassi (Day, 1870) from River Pamba,Southern Western Ghats,India

The present study provides the length‐weight relationships (LWRs) of two Ambassid fish species, Parambassis dayi (Bleeker, 1874) and Parambassis thomassi (Day, 1870) from River Pamba in Southern Western Ghats, India. Fishes were collected on a monthly basis between April 2014 to March 2015 using gill nets (1.0–3.0 cm), cast nets (1.0–2.0 cm) and seine nets (1.0 cm). The b values in the LWRs were estimated as 3.01 for P. dayi and 3.14 for P. thomassi. No previous information is available on LWRs for these two species in FishBase.     

Length‐weight relationships of Badis dibruensis Geetakumari and Vishwanath, 2010 (Badidae) and Lepidocephalichthys arunachalensis (Datta and Barman, 1984) (Cobitidae) from Subansiri River (Brahmaputra basin), Northeast India

Length–weight relationships (LWRs) for Badis dibruensis and Lepidocephalichthys arunachalensis, collected from the lower Subansiri River (Brahmaputra basin) in Assam, India from March 2016 to April 2017 using fishing gears namely cast nets (2.5 m, 1 m; 10–15 mm mesh size) and gillnets (30 × 0.9 m; 5–10 mm mesh size), are presented based on seasonal collections. The b values in the LWRs were determined as 2.56 for B. dibruensis and 3.28 for L. arunachalensis.     

Length–weight and length–length relationships for three Sillago species (Sillaginidae) from the Persian Gulf

This study investigates length–length and length–weight relationships of three Sillago species [Sillago arabica McKay & McCarthy (Memoirs of the Queensland Museum, 27, 1989, 551), Sillago attenuata McKay, 1985 and Sillago sihama (Forsskål, 1775)] captured in the Persian Gulf, Iran. A collection of 220 specimens was captured from August 2015 to January 2016 by cast net (mesh size: 10 mm) and beach seine (mesh size: 15 mm). The relationships of total length (TL) and standard length (SL) and the relationships between total length and body weight are given. This study presents the first reference on LWRs for two of the species (S. arabica and S. attenuata) in their range of distribution.     

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 Acanthopagrus longispinnis (Valenciennes, 1830), Raconda russeliana (Gray, 1831) and Coilia neglecta (Whitehead, 1967) from the Bay of Bengal coast,Bangladesh

Current study reports the length‐weight relationships (LWRs) of three marine fish species collected from the fishermen catches covering three seasons i.e., rainy, autumn and winter between June, 2016 and February, 2017. Fishermen caught the species using beach seine net (3.5 cm mesh size) and set bag net (0.5 cm mesh size) up to 200 m far away from the shoreline. The LWRs for fish species were W = 0.0180TL^3.192 for A. longispinnis, W = 0.0109TL^2.971 for R. russeliana and W = 0.0098TL^2.942 for C. neglecta with their r² values of 0.971, 0.962 and 0.997, respectively.