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.     

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 relationships for three fish species from Yalong River in China

This study provides the first report of length–weight relationships (LWRs) for three fish species collected from the Yalong River, one of the tributaries to the upper reaches of the Yangtze River, China. The LWRs of these fish species were BW = 0.0070TL^3.0539 (r² = 0.9662) for Schizothorax wangchiachii, BW=0.0134TL^2.8523 (r² = 0.9676) for Schizopygopsis malacanthus, and BW=0.0143TL^2.9253 (r² = 0.8538) for Euchiloglanis kishinouyei, respectively. Also investigated were the spawning season, absolute fecundity and main food items of the three fish species in the natural environment. In addition, new maximum sizes for the three species are provided.     

Gill monogenea of Rastrelliger spp. (Scombridae)

The following gill monogeneans are described, based on a survey of 240 Rastrelliger kanagurta, 12 R. faughni and 185 R. brachysoma (Scombridae) from many geographical areas: Eyelavera typica from R. kanagurta, R. faughni and R. brachysoma, Indomazocraes jagannath from R. kanagurta and R. faughni, Kuhnia sprostonae from R. kanagurta and R. brachysoma, and Kuhnia scombercolias from R. kanagurta and R. brachysoma. Eyelavera parukhini Lebedev, 1980 is synonymised with E. typica, Scomberocotyle eyela Unnithan, 1964 with Indomazocraes jagannath, Kuhnia microlepidotusi Gupta & Krishna, 1977 and K. kanagurta Mamaev & Parukhin, 1986 with K. sprostonae, K. arabica Mamaev & Parukhin, 1986 with K. scombercolias Nasir & Fuentes Zambrano, 1983. It is emphasized that populations of Monogenea from the same host species or genus in different geographical areas are likely to be conspecific, and should not be described as different species, if they differ only slightly from each other. Monogenea that differ from insufficiently described species in minor detail should not be described as new species unless material of the original species has been examined.     

Length–weight relationships of three fish species from the upper reaches of the Beijiang River,Shaoguan, China

Fish assemblages were randomly collected in March 2015 from the upper reaches of the Beijiang River, Shaoguan, China. Fish were sampled on 10 occasions using gill nets (mesh size: 3 cm) and the length–weight relationships (LWRs; W = a × L^b) of three native species recorded: Xenocypris davidi, Xenocypris macrolepis and Culter recurviceps. The exponent b varied from 2.803 to 3.096 and r² values ranged 0.985–0.992. This is the first report on the LWRs of fish from this area, with valuable results for the research, management and conservation of fishery resources in the upper reaches of the Beijiang River.     

Length‐weight relationships of two cyprinid fishes from the Beijiang River,Guangdong, China

This study reports the length‐weight relationships (LWRs) of Acrossocheilus beijiangensis Wu & Lin, 1977 and Barbodes semifasciolatus (Günther, 1868) from the upper reaches of Beijiang River, Guangdong Province, China. Sample sizes for the two fish species were 335 for A. beijiangensis and 106 for B. semifasciolatus. Fishes were collected on a monthly basis between November 2013 and December 2014 using gill nets (30 m long × 1.2 m high, mesh‐size 1.5 cm) and fish cages (mesh‐size 0.5 cm). LWRs were established as W = 0.0052L^3.3249 (r² = .9696) for A. beijiangensis and W = 0.0088L^3.2405 (r² = .9469) for B. semifasciolatus. No previous information is available on LWRs for these two species in FishBase.     

Length-weight relationship of fish species from Central Amazon floodplain

Length-weight relationship (LWR) for 39 freshwater fish species captured in the Catalão Lake, a floodplain area at the confluence of the Amazonas and Negro rivers is presented. LWRs were calculated based on fish sampled over 18 years (1999–2017) using a set of ten gill nets with different mesh sizes, monthly immersed in water for 24-hr with 6-hr interval catches. Measurements were done for standard length (SL – 0.1 cm precision) and total weight (TW – 0.01 g precision). The LWRs were calculated by the linear regression of natural log-transformed SL and TW data: TW = a × SL^b. All statistical analyses were performed with R software. From all species considered, 32 are new LWR records for the international literature as well as for the Amazonian ichythyofauna; additional records expand the known size range for seven species.     

Length‐weight and length‐length relationships of four small fishes from the Atrai River,Dinajpur, Bangladesh

Length‐weight (LWRs) and length‐length relationships (LLRs) were determined for four fish species collected from the Atari River in Dinajpur of Bangladesh. Sampling took place monthly between January and June 2016, using seine nets of commercial fishermen (mesh size 4 mm). In LWRs (r² > .927, p < .05), slope (b) was estimated as 3.191, 2.992, 3.217 and 3.109 for Acanthocobitis botia, Botia lohachata, Canthophrys gongota and Chanda nama, respectively. In LLRs (r² > .812, p < .05), lengths i.e. TL, SL, HL and FL were highly correlated. The present study on these species would be the baseline for FishBase dataset.     

Length‐weight relationships of three estuarine fish species from Bangladesh

The length‐weight relationships (LWRs) of three fish species; Toxotes chatareus (Hamilton, 1822), Datnioides polota (Hamilton, 1822), and Chela cachius (Hamilton, 1822) collected between September 2016 and August 2017 from Tentulia estuary of Bangladesh were analyzed. Fish were caught seasonally using set bag net and cast net with mesh size of 0.5 cm and < 0.5 cm, respectively. LWRs of Toxotes chatareus, Datnioides polota and Chela cachius were calculated as W = 0.0154L^2.926 (r² = .962), W = 0.0149L^3.106 (r² = .992) and W = 0.0109L^2.968 (r² = .981), respectively. The study provides a new maximum total length for Chela cachius.     

Length–weight relationships of two fish species from the middle reaches of the Jinsha River,China

This study provides the first report of length–weight relationships (LWRs) for Pseudogyrinocheilus prochilus (Sauvage & Dabry de Thiersant, 1874) and Jinshaia sinensis (Sauvage & Dabry de Thiersant, 1874) collected from the middle reaches of the Jinsha River, southwest China. Samples were obtained between June 2005 and November 2006. A total of 491 specimens belonging to two fish species were analyzed. LWRs were W = 0.0170L^2.970 (r² = 0.980) for P. prochilus and W = 0.0194L^2.849 (r² = 0.977) for J. sinensis. Prior to this study, the LWRs for P. prochilus were unknown. In addition, new maximum size for J. sinensis was provided.     

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.     

Biometric indices of five miniature fish from the catchment area of Kaptai Lake,Bangladesh

The present study reports on biometric indices comprising length-weight relationships (LWRs) of five miniature freshwater fish species from the Kaptai Lake, the largest lake in the People's Republic of Bangladesh. The study area included 3 stations in the 11,122 km² catchment area of the lake and each station was sampled from November 2017 to April 2018 using push net (mesh size 2 mm) for capturing the species. The values of growth coefficient b of the LWRs (W = aTL^b) of the species Oryzias dancena, Oryzias melastigma, Gobiopterus chuno, Brachygobius nunus and Badis chittagongis were 2.9575, 3.1467, 3.0535, 3.058 and 2.9396 with above 0.95 coefficient of correlation (r²). These results represent the first study of LWRs for these fish species which may help in management and conservation of the species in the whole country, including its geographical distribution.     

Length-weight relationships of 11 fish species from the Min River Estuary and its adjacent waters,Fujian Province,China

Length-weight relationships (LWRs) were estimated for 11 fish species from the Min River Estuary and its adjacent waters, Fujian Province, China. All samples were collected using gillnets (mesh size 45 mm) and bottom trawls (mesh sizes 45 mm at the main webbing and 25 mm at the cod end) seasonally in 2017 and 2018. The parameters for the LWRs were estimated, along with the basic Statistical analyses for total length and weight ranges as well as the 95% confidence intervals for the intercept (a) and the slope (b) of the regression lines. Further, the coefficient of correlation indicated that the LWRs were highly significant (all r² > .95, p < .001). This study provides the new maximum total lengths (TL_max) for Coilia grayii (33.0 cm), Johnius taiwanensis (20.9 cm), Johnius trewavasae (22.0 cm) and Cynoglossus sibogae (22.0 cm).     

Length‐weight and length‐length relationships of Oxynoemacheilus frenatus (Heckel, 1843) and Petroleuciscus esfahani Coad & Bogutskaya, 2010 from the Cheshmeh‐Langan river,Iran

The study presents length‐weight relationships (LWRs) and length‐lenght relationships (LLRs) for two freshwater fish species from the Cheshmeh‐Langan River (Iran; 32°50′N, 50°04′E), a part of the Tigris drainage basin. Fish were sampled by electrofishing (Samus 725M) in August and September 2017. The LWRs and LLRs obtained showed a high level of correlation (r² > .98).     

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 from the Dadu River and its tributaries,southwest China

Length‐weight (LWRs) and length–length (LLRs) relationships are reported for five fish species belonging to two families and five genera from the Dadu River and its tributaries, southwest China. In total, 605 specimens were collected by electrofishing and gillnets (mesh size ranging from 1.5 to 3.5 cm) in May and October 2013, May and October 2014, May and November 2015, and April and October 2016. The b‐values for LWRs varied from 2.571 to 2.952 (r² > .915). The results further indicated that the LLRs were highly correlated (r² > .978; p < .01). The two LWRs, five LLRs, and two maximum lengths are presented to FishBase for the first time. This biometric data and their relationships are relevant to the management and conservation of local fishes and fisheries.     

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 three fish species from Kerala waters,south‐west coast of India

Length–weight relationships (LWRs) of three fish species: Scomberomorus commerson, Alepes vari, and A. kleinii were estimated from Kerala waters, south‐west coast of India. Fish were captured between June 2016 and June 2017 by various gears such as ring seine (8–26 mm mesh size), trawl (30–40 mm cod end mesh size), hook and line (hook number VI–XII), smaller mesh sized drift gill net (26–90 mm) and larger one (120–170 mm) for bigger size fishes. Fish were collected on weekly basis from Cochin Fisheries Harbour (Lat. 09°56′327″N, Long. 76°15′764″E), Munambam Fisheries Harbour (Lat. 10°10′965″N, Long. 76°10′258″E), Kalamukku (Lat. 09°59′924″N, Long. 76°14′564″E) and Chellanam (Lat. 09°47′950″N, Long. 76°16′551″E). All LWRs were significant with r² values ranged from 0.944 to 0.996 and b values ranged from 2.722 to 3.021 (p < .001). In addition, this study provides the information on LWRs and new maximum size for Alepes vari and A. kleinii.     

Length‐weight relationships for three species of common scorpaenoids from Singapore

This study provides length‐weight relationships (LWR) for three common marine species collected from Singapore, a small tropical island country in southeast Asia, where monthly collections using seine netting and fish trapping were performed at six sites from January to December 2010. The LWRs of these three species were BW = 0.0348 SL^3.002 (n = 305, r² = .9747) for Paracentropogon longispinis, BW = 0.0315 SL^3.039 (n = 104, r  = .9798) for Trachicephalus uranoscopus and BW = 0.0651 SL^3.021 (n = 70, r² = .9601) for Synanceja horrida respectively.     

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.