Length–weight and length–length relationships of three ecologically important fishes caught from a wetland,northeastern Bangladesh

Length–weight relationships (LWRs) and length–length relationships (LLRs) of three ecologically important fishes (Aplocheilus panchax, Danio rerio and Esomus danrica) were reported from a wetland, northeastern Bangladesh (23 58 N, 89 38 E). Samples were collected monthly using traditional fishing gear including fine meshed (2.0 mm) push net and fine meshed (3.0–4.0 mm) surrounding net during January to December 2014. For each individual, total length (TL), fork length (FL) and standard length (SL) was measured to 0.1 cm, while body weight (BW) was measured to 0.01 g accuracy. Allometric coefficient (b) values were 3.10 for A. panchax, 3.38 for D. rerio and 3.52 for E. danrica. In addition, the LLRs were also highly significant with r² ≥ 0.954.     

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.     

Length–weight relationships of 12 indigenous fish species in the Gajner Beel floodplain (NW Bangladesh)

The length–weight relationships (LWRs) were studied for 814 individuals covering eight families and 12 species of fish, e.g., Botia dario, Botia lohachata, Channa orientalis, Esomus danricus, Heteropneustes fossilis, Macrognathus pancalus, Nandus nandus, Ompok pabda, Pethia phutunio, Pethia ticto, Trichogaster fasciata and Trichogaster lalius captured from the Gajner beel floodplain, northwestern (NW) Bangladesh. Samples were collected occasionally from catches of fishermen from November 2014 to October 2015 using different types of traditional fishing gear, including gill net (mesh size ranges from 1.0 to 3.0 cm), cast net (mesh size ranges from 1.0 to 2.0 cm), square lift net (mesh size ~1.0 cm) and conical and box trap. The total length (TL) and body weight (BW) were measured for each individual. The allometric co‐efficient b values ranged between 2.64 (B. lohachata) to 3.27 (N. nandus) and were highly significant, with p < .001 for all species. Additionally, for the first time, the study provides LWR information for B. dario, B. lohachata, E. danricus, O. pabda, T. lalius and P. phutunio, beneficial for fishery biologists and to update the online database (FishBase). The study also recorded a maximum length for P. phutunio. The present observations are significant for the sustainable management and conservation of these fishes in the Gajner beel floodplain, NW Bangladesh and the surrounding ecosystems.     

Length-weight relationships of seven cyprinid fish species from the Kaptai Lake,Bangladesh

Length-weight relationships (LWRs) were estimated for seven small indigenous cyprinid fish species including Securicula gora, Osteobrama cotio, Esomus lineatus, Pethia gelius, Megarasbora elonga, Gonialosa manmina and Glossogobius aureus occurring in the Kaptai Lake, Bangladesh. Fish were collected monthly basis between March and October, 2018 from fishermen catches landed in the fish landing center, Rangamati. Fishermen operated lift net (mesh size < 0.5 cm), punti net (mesh size < 0.5 cm) and cast net (mesh size < 0.5 cm) for capturing these species. The value of exponent b ranged between 2.769 and 3.212 and regression parameter r² was between 0.926 and 0.992. New maximum total lengths were recorded for E. lineatus and G. manmina in this study.     

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 relationships of five Triplophysa species from the northwest of China

Length‐weight relationships were estimated for five Triplophysa species from the northwest China. A total of 1,598 specimens were collected using set gillnets (mesh size 1.5 cm) and ground bamboo cages in May 2012, and August 2014. This study presents the first references on LWRs for Triplophysa minuta, T. siluroides, and T. tenuis, and two new maximum length records for T. yarkandensis and T. strauchii. Statistical length–weight relationships for all five species were highly significant (p < .001), with R² values >.915.     

Length–weight relationship and condition factor of the Characidae matrinxã, Brycon falcatus (Müller & Troschel, 1844), in the Teles Pires River,southern Amazon

The aim of this study was to verify whether the in situ supply of soybean as a fish attractant bears any influence on the length–weight relationship and condition factor of the omnivorous fish species, Brycon falcatus. In addition, estimated was the length–weight relationship, standard and total length, condition factor, and size of B. falcatus in the spawning period in the Teles Pires River Basin. In the experimental design, rivers of the Teles Pires Basin containing soybean attractant (Verde River, Celeste River, Teles Pires River and the Tapaiuna River) were mapped. Fish were also collected from the Cristalino River, which contained no soybean attractant (treatment control). Samples were collected from August 2012 to July 2013. Length–weight relationship of B. falcatus in the Teles Pires River Basin can be obtained by the expression: Wt = 0.0091*SL^3.376, r² = .97, n = 102, and length‐length relationship: TL = 1.128*SL + 3.978, r² = .96. The condition factor of all specimens collected in the Teles Pires Basin was k = 1.055. Size at capable phase (L50) of spawning was estimated at 23 cm standard length. Results showed no significant difference in the length–weight relationship or condition factor of B. falcatus collected from rivers with or without soybean attractant. Concluded is that the in situ supply of soybean as a fish attractant does not interfere with the wellbeing of B. Falcatus in the Teles Pires River Basin.     

Length–weight and length–length relationships and seasonal condition factors for two mudskippers,Periophthalmus modestus (Cantor, 1842) and P. magnuspinnatus (Lee,Choi & Ryu, 1995) (Gobiidae), on tidal flats of Korea

Presented are the length–weight and length–length relationships and condition factors for two mudskippers, Periophthalmus modestus and Periophthalmus magnuspinnatus, on the tidal flats of Korea. Values of the exponent b, estimated by nonlinear least squares from weight and length data, were 3.031 for P. modestus and 3.044 for P. magnuspinnatus. All relationships between total and standard length were linear (r² > 0.974). The condition factors were significantly higher during the post‐spawning season than at other times for both species.     

Length‐weight and length‐length relationships of thirteen fish species from the lower Jinsha River,southwest China

Length‐weight and length‐length relationships were investigated for 13 freshwater fish species from the lower Jinsha River, southwest China (from 101°32′49.63″E; 26°35′38.27″N to 104°37′48.14″E; 28°45′59.55″N). Fish were sampled from five sites during 2014 and 2016, using trap‐nets, gillnets (major mesh size: 2–6 cm), longline and electrofishing. Length‐weight relationships for six and length‐length relationships for 12 species are the first report to FishBase, respectively. Moreover, new maximum length for 11 species are also presented to FishBase in this study. All regressions were highly significant (p < .001), with the coefficient of determination r² > .950. These information will be helpful for management and conservation in local fishes and fisheries.     

Length–weight relationships of four small indigenous fish species from an inland artisanal fishery,Bangladesh

This study reports the length–weight relationships (LWRs) of four small indigenous species, Trichogaster lalius (Hamilton, 1822), Nandus meni (Hossain & Sarker, 2013), Lepidocephalichthys annandalei (Chaudhuri, 1912) and Botia dario (Hamilton, 1822) collected between July 2015 and August 2016 from fishermen's catches landed in an inland fish landing center, northeastern Bangladesh. In the study, a new maximum total length (TL) is given for L. annandalei and LWRs of three species T. lalius, N. meni and L. annandalei for the first time in FishBase. Estimated LWRs were W = .014 TL^3.17, (r² = .982) for T. lalius, W = .006 TL^3.38, (r² = .961) for N. meni, W = .004 TL^3.27, (r² = .965) for L. annandalei and W = .020 TL^2.87, (r² = .978) for B. dario.     

Length-weight relationship of 16 fish species from the Negro River basin (Amazonas state,Brazil)

This study aimed to estimate the parameters of length-weight relationship for 16 freshwater fish species that inhabit the Aracá and Demeni Rivers, which are two tributaries of the Negro River (Amazonas state, Brazil). The fishes were sampled using gillnets (15 × 2 m, mesh size 30–120 mm between opposite knots), during 6 days each year, in April 2016, November 2018 and April 2019. The gillnets were placed in the river twice each day; in the morning (5–9 a.m.) and in the evening (5–9 p.m.), with a standardized time of 4 hr. Measurements were taken for standard length (SL – 0.1 cm precision) and total weight (TW – 0.01 g precision). The parameters a and b of the equation W_T = a.L_T^b were estimated. This study also provides new data on of maximum lengths for six species, namely, Argonectes longiceps, Hemiodus atranalis, Chalceus erythrurus, Astrodoras asterifrons, Trachydoras steindachneri and Acarichthys heckelii.     

Length–weight relationships of two native fish species from the upper reaches of Nujiang River,Southwest of China

The length–weight relationships (LWRs) were determined for two native cyprinid fishes: Poropuntius opisthopterus (Wu, 1977) and Raiamas christyi (Boulenger, 1920) collected from the upper reaches of Nujiang River (31°33′29″N; 92°55′58″E), Southwest of China. A total of 162 specimens were collected quarterly between March 2015 and November 2016. Fish were sampled by electrofishing in 12 wadable sites with maximum water depth 60–70 cm. The b values parameter in the length–weight relationship equations were calculated as 2.90 for P. opisthopterus and 3.45 for R. christyi. This study represents a new maximum standard length record for P. opisthopterus.     

Length–weight relationships of six fish species from the headstream region of the Dongjiang River,China

Dongjiang River, a main tributary of the Pearl River, is geographically situated in South China. The present study describes the length–weight relationships (LWRs) of six fish species (Acrossocheilus paradoxus, Barbodes semifasciolatus, Onychostoma elongatum, Microphysogobio fukiensis, Microphysogobio kiatingensis, Metzia lineata) from the headstream region of the river including five Chinese endemic species (A. paradoxus, B. semifasciolatu, O. elongatum, Mi. fukiensis, Mi. kiatingensis). Fish species of five genera of the same family were collected quarterly from April 2012 to October 2014 by using non‐selective fishing gears: drag nets (5 m, mesh‐size 3 cm), drift gillnets (30 × 15 m, mesh‐size 5 mm), fish cages (4 m, mouth opening 40 × 40 cm), scoop nets (mesh‐size 0.5‐1 cm), and electro‐fishing (12V, 200 Hz). The parameter a and b in the LWR equations (W = a L^b) ranged from 0.0014 to 0.0228, and 2.89 to 3.18, respectively. Compared with FishBase, this study provides the first LWR records for four cyprinids (A. paradoxus, B. semifasciolatu, O. elongatum, Me. lineata) and a new record of maximum body length for O. elongatum.     

Length–weight relationships of three fish species from Trasimeno Lake,Italy

Length–weight relationships for Alburnus arborella, Esox cisalpinus and Scardinius hesperidicus from Trasimeno Lake are provided. A total of 4,205 specimens were collected for examination from 2008 to 2014 throughout the lake by means of electrofishing and nets. For all species the value of b ranged from 2.887 for Esox cisalpinus males to 3.115 for Scardinius hesperidicus. The study provides the first reference of length–weight relationships for the three species. A new maximum total length is also reported for E. cisalpinus.     

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 for six fish species from the middle of the Yalu Tsangpo River,China

This paper reports the length–weight relationships for six fish species belonging to the Cyprinidae from the middle of the Yalu Tsangpo River in China. Samples were obtained by electroshock and drift net fishing techniques (mesh size 2 cm × 3 cm; 200 m net length) in April and September to October 2014. Length–weight relationships estimates for these species were not available in FishBase. A total of 737 specimens were used to estimate the a and b parameters. New maximum total lengths are also reported for six species. The r² values range from 0.98 to 0.99. Values of b vary from 2.88 to 3.19.     

Length–weight relationships of two endemic species of Alburnoides nicolausi (Bogutskaya & Coad, 2009) and Alburnus zagrosensis (Coad, 2009) in Houzian River,Lorestan Province,Iran

This investigation prepares the length–weight relationships (LWRs) of two fish species, including Alburnoides nicolausi (Bogutskaya & Coad, 2009) and Alburnus zagrosensis (Coad, 2009) from Houzian River (latitude 33°22′15.20″ to 33°21′31.57″N; longitude 49°44′39.66″ to 49°44′17.67″E), Lorestan province, Iran. Fish specimens were collected monthly using seine net with 5 mm (Stretched) mesh size between April to September 2017. The LWRs for fish species were W = 0.0059L^3.405 (male) and W = 0.0053L^3.494 (female) for A. nicolausi, W = 0.0035L^3.341 (male) and W = 0.003L^3.387 (female) for A. zagrosensis, respectively. The highest value of r² was .931 for male of A. zagrosensis and lowest value was .964 for male of A. nicolausi.     

Length–weight and length–length relationships of five fish species in the Atrai River,Dinajpur, Bangladesh

A total of 502 specimens were obtained during monthly samplings from July to December 2015, by fishermen using seine nets, gillnets and cast nets. Length–weight (LWRs) and length–length (LLRs) relationships were estimated for five fish species collected from the Atrai River in the northwestern region of Bangladesh. The values of slope (b) in LWRs (r² > .913, p < .001) were determined as 2.899 for Aspidoparia jaya, 3.059 for Gagata cenia, 3.004 for Gagata youssoufi, 2.755 for Salmophasia bacaila, and 3.222 for Salmophasia phulo, respectively. The linear relationships in TL, FL and SL were highly correlated (for all cases: r² > .897, p < .001). No previous information on LWRs (except for G. cenia) and LLRs (except for S. bacaila) of these selected species were found in FishBase.     

Length–weight relationships of 10 freshwater fish species from an intermittent river basin,semi‐arid region,Brazil

The length–weight relationships for 10 freshwater fish species from an intermittent river basin in a semi‐arid region of Brazil were analyzed. Specimens were caught using a dragnet (3.5 × 2.5; stretched mesh size 5 mm) during running and pool phases from January to November 2015. The specimens were measured for total length and weight. Previously unavailable in FishBase, the detailed length–weight relationships of Compsura heterura, Phenacogaster calverti, and Serrapinnus piaba are reported for the first time. All fish collected presented total lengths (TL) lower than the maximum reported in FishBase.     

Length‐weight relationships of four fish species from Visakhapatnam coast,India

Length‐weight relationships (LWRs) were determined for 4 deep water fish species from Visakhapatnam coast, India. Specimens were collected fortnightly between December 2013 and November 2015 from commercial trawls at Visakhapatnam fish landing centre (16.98°N–20.2°N, Long.82.19°–86.53°E). Individuals were captured between 100 and 300 m depth with shrimp trawl net (head rope length: 37–46 m and cod end mesh size: 30–40 mm). Total length (TL) (nearest to 0.1 cm) and body weights (nearest to 0.1 g) were taken each individual. All LWRs were significant with r² values ranged from 0.958 for Uranoscopus bicinctus Temminkc & Schlegel, 1843 to 0.983 for Uranoscopus chinensis Guichenot, 1882 and “b” values ranged from 2.832 for U. bicinctus to 3. 402 Synodus indicus (Day, 1873).This study provides a new maximum length data for three species (Uranoscopus bicinctus Temminkc & Schlegel, 1843; Uranoscopus chinensis Guichenot, 1882 and Uranoscopus marmoratus Cuvier, 1829).