Length–weight and length–length relationship of Thryssa purava (Hamilton, 1822), Thryssa polybranchialis Wongratana, 1983 and Thryssa mystax (Bloch & Schneider, 1801) from Chilika lagoon,India

Current study provides basic information on Length–weight relationship (LWR) and length‐length relationship (LLR) of three fish species of genus Thryssa (Clupeiformes: Engraulidae) i.e., Thryssa purava (Hamilton, 1822), Thryssa polybranchialis Wongratana, 1983 and Thryssa mystax (Bloch & Schneider, 1801) from Chilika Lagoon, India. Samples were collected during the monsoon (July) and post‐monsoon (November) seasons in 2016 and during the pre‐monsoon season (May) in 2017, using screen barrier nets (mesh size 8–18 mm) and gill nets (mesh size 14 and 16 mm). The b values were determined from LWRs as 3.026 for Thryssa purava, 3.326 for Thryssa polybranchialis and 3.081 for Thryssa mystax.     

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 five needlefish species from Kerala waters,south‐west coast of India

Length‐weight relationships (LWRs) were estimated for five needlefish species such as Ablennes hians (Valenciennes, 1846), Tylosurus crocodilus (Péron & Lesueur, 1821), Tylosurus acus melanotus (Bleeker, 1850), Strongylura leiura (Bleeker, 1850), and Strongylura strongylura (van Hasselt, 1823). Specimens were collected on weekly basis from Cochin Fisheries Harbour (Lat. 09056′327″N, Long. 76015′764″E), Munambam Fisheries Harbour (Lat. 10010′965″N, Long. 76010′258″E), Kalamukku (Lat. 09059′924″N, Long. 76014′564″E) and Chellanam (Lat. 09047′950″N, Long. 76016′551″E), between October 2015 to August 2017. Fish were captured by traditional long liner (hook no. IX‐XIV) and ring seiner (mesh size 8–24 mm). The estimated allometric co‐efficient b values ranged from 3.063 (Tylosurus acus melanotus) to 3.962 (Strongylura leiura) and r² values ranged from 0.850 (Tylosurus acus melanotus) to 0.992 (Tylosurus crocodilus). All the LWRs were highly significant, with p < .001. In addition, the study provides the first estimate of LWR for Tylosurus acus melanotus and new estimate for other four species of needlefish.     

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 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).     

Length–weight relationships of eight deep‐sea fish species collected from the southwest coast of India

Length‐weight relationships (LWR) for eight deep‐sea fishes belonging to six families collected from the south west coast of India are presented. Specimens were caught by deep‐sea shrimp trawls with mesh size 24 mm during 2011 and 2013. The b values ranged from 2.13 to 3.71 and the coefficient of determination (r²) ranged from 0.84 to 0.98. A new standard length maximum was recorded for Neoscopelus microchir. The b values estimated during the present study were compared with the values estimated using models based on Bayesian approach deposited in Fish Base.     

Length‐weight relationships of 10 coastal fish species from the Visakhapatnam coast,India

We analysed the length‐weight relations (LWRs) of 10 fish species inhabiting different habitats from Visakhapatnam, Coast of India. Samples were obtained between August 2013 and December 2016 from commercial trawlers at the local fish landing centre (16.98°N–20.20°N, Long.82.19°–86.53°E). Fishes were captured between 100 and 300 m depth with demersal trawl net (head rope length: 46 m and cod end mesh size: 40 mm with a 38 m high speed. Total length (TL; nearest to 0.1 cm) and body weights (nearest to 0.1 g) were taken from each individual. This study provides new maximum length data for two species (Archamia bleekeri (Günther, 1859) and Ostorhinchus fleurieu (Lacepède, 1802), and LWR estimates for rare deep reef associated fishes are provided for the first time. All LWRs were significant with r² values ranging from .908 for Sargocentron praslin (Lacepède, 1802) to .981 for Parapercis pulchella (Temminck & Schlegel, 1843) and “b” values ranged from 2.5216 for Parapercis pulchella (Temminck & Schlegel, 1843) to 3.4746 for Ostorhinchus fleurieu Lacepède, 1802.     

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 and Length‐length relations of four fish species from the Chilika Lake,East coast of India

This study reports the length–weight relationship (LWR) and length‐length relationship (LLR) estimated for four fish species inhabiting in Chilika Lake, India. Total 504 specimens were sampled from mono‐filament gill nets (mesh size 12 mm, 22–24 mm, 34–38 mm, 42 mm) during January 2015 to December 2015. The estimated b values from LWR ranged between 2.79 (T. biaculeatus) to 3.29 (C. praeustus). In all species, the relationships between length‐weight and length‐length were highly correlated (p < .05). The study provides first world reports on LWRs and LLRs for all the 4 studied species.     

Length weight relationship of five deep sea fishes from Kerala,south west coast of India

Length–weight relationships (LWRs) were estimated for five deep sea fishes viz. Astronesthes martensii, Glyptophidium macropus, Neobythites multistriatus, Physiculus roseus, Synagrops japonicus from Kerala, south west coast of India. Fishes were collected from commercial trawlers monthly from February 2018 to March 2019 operating at depth ranged from 270 m (Lat. 9°29.35′ N, Long. 75°44.74′ E) to 350 m (Lat. 9°26. 49′ N, Long. 75°42.36′ E) in the south east Arabian Sea. Correlation coefficients (r²) were found high for all species, with b value ranged from 2.923 to 3.404.     

Length‐weight relationship and reproductive parameters of Botia dario (Hamilton, 1822) in Assam,India

The length‐weight relationships, spawning season, sex ratio, size at first maturity and fecundity of Botia dario (Hamilton, 1822), also known as the Bengal loach, were analyzed based on 556 specimens collected from the wetlands of Majuli Island, Assam between June 2012 and May 2013. The sex ratio (M : F) was 1 : 0.68, differing significantly (P < 0.05) from a 1 : 1 ratio. Size at first maturity (L_m50) was estimated as 6.8 cm for males and 7.4 cm for females. Analysis of monthly variations in the gonado‐somatic index (GSI), the monthly proportions of macroscopic gonadal maturity, and the ova diameter suggest a prolonged spawning season of B. dario from May to August, with a peak in July for both males and females (GSI = 15.0 in females; 7.0 in males). Absolute fecundity varied from 2523 to 51 377, with a mean of 18 367 ± 1254 oocytes per ovary. A positive correlation was recorded between total fecundity and body weight (r² = 0.678).     

Length–weight relationship of selected elasmobranch species from north‐eastern Arabian Sea,India

Length–weight relationship (LWR) was estimated for 12 elasmobranch species; five shark species, four species of rays and three species of guitar fishes from north‐eastern Arabian Sea, India. Five major landing centres of Maharashtra were selected; Satpati (Lat. 19°43′15″N, Long. 72°42′00″E), Naigaon (Lat. 19°19′32″N, Long. 72°48′54″E), Versova (Lat. 19°08′33″N, Long. 72°48′11″E), New ferry Wharf (Lat. 18°57′29″N Long. 72°51′01″E) and Sassoon dock (Lat. 18°54′42″N, Long. 72°49′33″E). Samples were collected fortnightly during August 2016 to October 2017 from various gears; drift gill nets (Hung length 114–143 m and #100–270 mm) off Satpati coast at 35–50 m depth, dol nets (length 50–65 m and cod end # 30–69 mm) in Naigaon at 38–50 m depth and trawl (length 33–72 m and cod end # 17–32 mm) in Versova, New ferry Wharf and Sassoon dock operated at 20–50 m depth. Multiday fishing was carried out with 2–3 fishing trips in a month, each trip with duration of 7–13 days. Soaking time of gill net and dol net varied from 4 to 8 hr while each trawl haul lasted for 3–4 hr. Length–weight/Disc‐width‐weight relationship showed good fit with r² values varying from 0.818 to 0.999. In addition to information on LWR, new maximum size for three species of elasmobranchs is reported in this paper.     

Length‐weight relationships (LWRs) of Wallago attu (Bloch and Schneider) from Manchar Lake Jamshoro,Sindh, Pakistan

The present study was undertaken to assess length‐weight relationships (LWRs) of Wallago attu (Bloch and Schneider, 1801) from Manchar Lake, in Pakistan. A total of 251 specimens collected from August 2011 to April 2012 were examined. Length‐weight equations were W = 0.00464 L ^3.0819 (combined), W = 0.00387 L ^3.120 (males) and W = 0.00632 L ^3.00892 (females).     

Length‐weight relationship of ten indigenous freshwater fish species from Gandak River,Bihar, India

Ten indigenous freshwater fish species belonging to nine genera and seven families were collected from Gandak River, Bihar, India during December, 2014 to September, 2016. Fishes were caught using Cast nets, Gill nets, Drag nets with mesh size of 15–20 mm, 25–30 mm and 5–10 mm respectively along with Traps. Sampling was done during dry and wet seasons and a total of 682 fish were collected for analysis of their Length–Weight Relationships (LWRs). Analyses included seven species for which no previous LWRs information were available in FishBase, and new maximum lengths were recorded for three species.     

Length–weight relationship of main commercial fishes from the French Catalan coast

Length–weight relationships (LWRs) are presented for 49 Mediterranean fish species occurring on the French Catalan coast. Captures were made between February 2007 and July 2010. The results also provide new maximum lengths for four species and new maximum weights for a number of species.     

Length–weight relationships for four mullets from the Chilika lagoon,East coast of India

Current study provides information on Length–weight relationship (LWR) of four fish species of family Mugilidae i.e., Planiliza macrolepis (Smith, 1846), Chelon parsia (Hamilton, 1822), Osteomugil cunnesius (Valenciennes, 1836) and Valamugil speigleri (Bleeker, 1858) from Chilika Lagoon, East coast of India. Samples were collected during monsoon (July 2016), winter (November 2016) and summer (April 2017) seasons from the fisher's boats inside the lagoon while fishing with screen barrier nets (mesh size 18‐38 mm) and gill nets (mesh size 34, 38, 46, 62 and 86 mm). The b values were determined from the data set in LWRs as 2.958 for P. macrolepis, 2.952 for O. cunnesius and 2.919 for C. parsia and 2.883 for V. peigleri. In all species, regression values were statistically significant (p < .05).     

Length‐weight relationships of seven fish species from Amazonian Equatorial coast,Brazil

Parameters of the length‐weight relationship (LWR) were estimated for seven fish species from Amazonian Equatorial coast of Maranhão, Brazil. Samplings were carried out in three sample points of the lower stretch of the Itapecuru River (2°57'6.2"S and 44°14'26.5"W; 3°0'33.0"S and 44°15'54.7"W; 3°3'42.9"S and 44°15'1"W). The specimens were caught quarterly from June 2012 to August 2014 using monofilament gillnets (10, 20, 30, 40, 50, 60, 70 and 80 mm between knots) from 10 m to 30 m long and 4 m to 6 m high. This study provides the LWR parameters for Schizodon dissimilis, Curimata macrops, Prochilodus lacustris, Geophagus surinamensis, Hassar affinis, Platydoras brachylecis and Hypostomus plecostomus.     

Length‐weight relationships of five fish species in Tibet,southwest China

Length‐weight relationships (LWR) were evaluated for five species: Schizothorax integrilabiatus (Wu et al., 1992); Shizopygopsis stoliczkai Steindachner, 1866; Gymnocypris chui Tchang, Yueh & Hwang, 1964; Gymnocypris scleracanthus Tsao, Wu, Chen & Zhu, 1992; and Triplophysa tibetana (Regan, 1905). A total of 567 specimens were collected whereby S. integrilabiatus was caught with 12‐volt electric fishing gear (water depth, 1 m) in Buqun Lake in May 2015. Both G. chui and G. scleracantus were caught with 12‐volt electric fishing gear (water depth,1 m) and set gillnets (mesh size 3 cm) in Lange Lake in July 2015, S. stoliczkhai was caught with 3 cm mesh size set gillnets in Shiquan River in August 2015, T. tibetana was caught with 12 V electric fishing gear in the Zhongba reach of the Yarlung Zangbo River in August 2015. This study provides the first published length–weight references on LWR for the five species. New maximum total lengths were recorded for three species, including Shizopygopsis stoliczkai, Gymnocypris chui, and Gymnocypris scleracanthus.