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 and length–length relationships of seven freshwater fish species from the Daning River,a tributary of the Yangtze River,southwest China

This study determined the length–weight relationships (LWRs) and length–length relationships (LLRs) of seven freshwater fish from the Daning River, a tributary of the Yangtze River, southwest China. Specimens were collected between July 2016 and July 2017 using drift gill nets (mesh size 1, 2 and 3 cm), cage net (0.5 cm mesh size) and electroshock fishing techniques quaterly. Parameter b values of LWRs ranged from 2.647 to 3.276 (r² > .963) and b values of LLRs ranged from 1.091 to 1.213(r² > .985). Six new LLRs and seven new maximum length data are presented. The biometric data and their relationships are relevant to Fishers science to supplement other data sets needed for fisheries management.     

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 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 relationships of three catfish species from a tributary of the Dhaleshwari River,Bangladesh

The present ichthyological report describes the length‐weight relationships (LWRs) of three catfish species (Eutropiichthys murius, Nangra nangra and Gagata viridescens) belonging to two families from the Kaliganga River, a tributary of the Dhaleshwari River, Bangladesh. The analyses included 306 specimens collected monthly from fishermen's catches during October 2015 to April 2016. Ranges of regression parameters a and b of the three species were within 0.0058–0.0099 and 2.900–3.142, respectively with highly correlated coefficients of determination (r² > .995; p < .001). The LWRs for all three species presented herein for the first time with a new maximum length record for N. nangra.     

New maximum size records and length–weight relationships for two species,Corica soborna (Hamilton, 1822) and Mystus bleekeri (Day, 1877), from the Ganges River (NW Bangladesh)

This study records new maximum lengths and provides length–weight relationships (LWRs) for two small indigenous fishes, Corica soborna (Hamilton, 1822) and Mystus bleekeri (Day, 1877), from the Ganges River in northwestern Bangladesh. Fishes were sampled sporadically using gill nets and cast nets from August 2015 to July 2016. New maximum recorded lengths weere 5.3 cm total length (TL) for C. soborna and 17.7 cm TL for M. bleekeri. The LWRs were highly significant (p < .001) with r² values >.958. These findings will play a significant role in the fisheries resource management.     

Length–weight and length–length relationships of eight fish species from river Ganga,India

Present study provides length–weight relationships (LWRs) and length–length relationships (LLRs) of eight fish species from river Ganga, India. Specimens were sampled from gill nets (mesh, 22–120 mm), cast nets (mesh, 12–14 mm), and seine nets (mesh, 12 mm) on quarterly basis from September 2016 to September 2017 within the river stretch from 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). The b value ranged from 2.86 (Otolithoides pama) to 3.08 (Polynemus paradiseus), whereas a value ranged from 0.004 (P. paradiseus) to 0.016 (Rita rita). Both relationships (LWRs and LLRs) were found to be highly correlated (p < .001). This study provides first report on LWR for Amblyceps mangois and Osteobrama cotio, whereas new maximum length recorded for Macrognathus pancalus. Furthermore, the estimate of R. rita should be considered as tentative because of the limited size range in the study.     

Length–weight and length‐length relationships of four endemic fish species caught from Payra River,Southern Bangladesh

The present study estimated the length–weight relationship (LWR) and length‐length relationships (LLR) of four fish species, Ompok pabo (Hamilton, 1822), Acentrogobius cyanomos (Bleeker, 1849), Acentrogobius caninus (Valenciennes, 1837) and Gagata cenia (Hamilton, 1822) collected from the Payra river over a period of 1 year between July 2015–June 2016 using set bag nets and cast nets with a mesh size of 0.5 cm and <0.5 cm, respectively. Altogether 593 individuals of O. pabo (59), A. cyanomos (221), A. caninus (240) and G. cenia (73) were sampled and studied. LWRs of O. pabo, A. cyanomos, and A. caninus are presented for the first time in Fishbase.     

Length–weight and length–length relationships of five threatened fish species from the Jamuna (Brahmaputra River tributary) River,northern Bangladesh

The small indigenous species, namely Ailiichthys punctata (Day, 1871), Botia lohachata (Chaudhuri, 1912), Chanda nama (Hamilton, 1822), Laubuca laubuca (Hamilton, 1822) and Mystus cavasius (Hamilton, 1822), comprise an important component of riverine fisheries of Bangladesh. This study describes the length–weight relationships (LWRs) and length–length relationships (LLRs) of five threatened fishes from the Jamuna River, a distributary of the Brahmaputra River in northern Bangladesh. A total of 919 specimens from five species in five families used for this study were caught by traditional fishing gear, March 2010 through February 2011. The allometric coefficient (b) of the LWRs indicated negative allometric growth in A. punctata, B. lohachata, and C. nama (b < 3.00), but positive allometric growth in L. laubuca and M. cavasius (b > 3.00). Furthermore, the LLRs were highly correlated (r² > 0.978; P < 0.001). This study presents the first reference on LWRs and LLRs for these threatened species in Bangladesh. The results would be useful for sustainable management and conservation of the limited stocks in the Brahmaputra River ecosystem.     

Length–weight relationships of four fish species from a coastal artisanal fishery,southern Bangladesh

This study presents the first report of length–weight relationships (LWRs) for Apocryptes bato (Hamilton, 1822), Salmophasia phulo (Hamilton, 1822), and Silonia silondia (Hamilton, 1822), excluding Anodontostoma chacunda (Hamilton, 1822), from fishermen's catches landed in a coastal artisanal fishery at Patuakhali, Southern Bangladesh. Specimens were sampled occasionally over a period of 1 year between August 2014 and September 2015. Fishes were collected from coastal fishermen using cast nets (mesh size <0.5 cm) for A. bato, set bag nets (mesh size 0.5 cm) for A. chacunda and S. silondia, and lift nets (mesh size <0.5 cm) for S. phulo. The LWRs obtained were W = 0.006L^2.99, (r²) = 0.976, W = 0.011L^3.04, (r²) = 0.971, W = 0.006L^3.00, (r²) = 0.945 and W = 0.007L^2.99, (r²) = 0.988 for A. bato, A. chacunda, S. phulo, and S. silondia, respectively.     

Length–weight and length–length relationships of five Mystus species from the Ganges and Rupsha rivers,Bangladesh

This study focused on the length–weight and length–length relationships of five Mystus species from Bangladesh. A sum of 398 individuals (Mystus bleekeri = 47, Mystus cavasius = 171, Mystus gulio = 59, Mystus tengra = 65, and Mystus vittatus = 56) was collected from the Ganges and Rupsha rivers, Bangladesh. Fishes were caught by gill net (mesh sizes: 2.0–4.0 cm) and cast net (mesh sizes: 1.5–3.0 cm) from July 2014 to June 2015. Total length (TL), fork length (FL) and standard length (SL) were measured to 0.1 cm, while whole body weight (W) was taken to the nearest 0.1 g for each individual. The TL ranged from 6.0–13.5 cm for M. bleekeri, 5.0–15.0 cm for M. cavasius, 7.4–17.2 cm for M. gulio, 4.6–11.6 cm for M. tengra and 5.5–12.3 cm for M. vittatus. The W varied from 3.0–18.2 g for M. bleekeri, 1.3–30.4 g for M. cavasius, 6.1–62.2 g for M. gulio, 1.7–15.1 g for M. tengra and 2.7–19.2 g for M. vittatus. All LWRs were highly significant (p < .001), with all r² values ≥.950. The LLRs were also highly significant (p < .001), with all r² ≥.980. This study provides information on LWRs and LLRs for M. gulio and M. tengra for the first time. The results of this study can be very effective for stock assessment of Mystus species in the Ganges and Rupsha rivers as well as in the surrounding ecosystems.     

Length–weight relationships for eight fish species from the Ravi River,north‐western India

Length–weight relationships (LWRs) were evaluated for Badis badis (n = 25), Sperata seenghala (n = 26), Labeo gonius (n = 34), Rasbora rasbora (n = 30), Bagarius bagarius (n = 24), Gagata cenia (n = 27), Glyptothorax stoliczkae (n = 24) and Channa orientalis (n = 28) from the Ravi River tributary in North India. Altogether 218 samples of eight species were obtained between May and November 2014 using cast nets and gill nets. LWRs for these species were unknown to FishBase, and new maximum lengths were recorded for two of these species.     

Length–weight and length–length relationships of four fish species from the middle reaches of the Minjiang River,southwest China

Length–weight (LWR) and length–length (LLR) relationships are reported for Glyptothorax fokiensis (Rendahl, 1925), Microphysogobio kachekensis (Oshima, 1926), Pseudobagrus brevicaudatus (Wu, 1930), and Sinibrama taeniatus (Nichols, 1941) from the middle reaches of the Minjiang River and its tributaries, Sichuan Province, in southwest China. A total of 675 specimens were obtained between 2013 and 2016 using various types of fishing gear and electroshock fishing techniques. Standard length and total length for each individual were measured by digital slide caliper and each body weight was taken by digital balance. The b‐values for LWRs varied from 2.617 to 3.249 (r² > .954), and the LLRs were highly correlated (r² > .983; p < .01).     

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 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 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 26 fish species from the Yiluo River,a tributary of the Yellow River,China

From February to October 2016, a total of 9,754 fish specimens were collected from the Yiluo River, a tributary of the Yellow River, China's second longest river. Based on these samples, length–weight relationships (LWRs) and length–length relationships (LLRs) were estimated for 26 species. Among these data, LWRs for 1 species, LLRs for 11 species, and maximum total lengths for six species were not previously recorded in FishBase. The a values of the LWRs varied between 0.0019 and 0.0116, and b values from 2.805 to 3.883. All regressions for LWRs and LLRs were highly significant (p < .001). These results will be useful for sustainable management and conservation of the fish resources in the Yiluo River and the Yellow River ecosystem.     

Length‐weight and length–length relationships of three algae‐scraping cyprinid species from Iran

The study presents length–weight relationships (LWRs) and length–length relationships (LLRs) for three algae‐scraper species; Capoeta coadi from the Kouhrang River (Iran; 32°23′N, 50°08′E) a part of the Tigris drainage basin, Capoeta pyragyi from Cheshmeh Langan River (32°55′N, 50°10′E) a part of Zayanderud River basin and Capoeta umbla from Chooman River (35°57′N, 45°47′E). Fish were sampled by electro fishing (Samus1000; Power Out: 200 watts) in August, September and October 2017. Sampling was carried out each months in sites covering an area of about 100 m² including runs, riffles and pools at a water depth of 10–60 cm. The obtained LWRs and LLRs showed a high level of correlation (r² > 0.99).     

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 and length‐length relationships and form factor of three threatened fishes from the Ganges River (NW Bangladesh)

Data and information are needed to avert the alarming decline and initiate conservation measures for three threatened fishes, Labeo boga (Hamilton, 1822), Nandus nandus (Hamilton, 1822) and Puntius ticto (Hamilton, 1822), from the Ganges River and surrounding ecosystems. These fishes are decreasing rapidly due to high fishing pressures as well as environmental degradation. This study furnishes the length–weight relationships (LWRs), length–length relationships (LLRs) and form factor (a_3.0) of these three threatened species from the Ganges River, northwestern Bangladesh. A total of 773 specimens from the three species and two families used for this study were caught by traditional fishing gear between April 2011 and March 2012. The analysis of covariance (ancova ) revealed significant differences between the sexes in LWRs for L. boga (P < 0.001), but not with the remaining species (P > 0.05). Furthermore, the LLRs were highly correlated (r² > 0.983; P < 0.001), and ancova analyses additionally indicated that LLRs did not differ between sexes (P > 0.05). The calculated form factor (a_3.0) was 0.0111, 0.0159 and 0.0129 for L. boga, N. nandus and P. ticto, respectively. This study presents the first references on LWRs, LLRs and form factor for these three threatened species in Bangladesh. The results would be useful for further studies on the population assessment and sustainable conservation of the limited stocks in the Ganges River ecosystem.