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 three fish species from the Tibet reach of the Lancang River,China

Length‐weight relationships (LWRs) were determined for three fish species, Schizothorax lantsangensis (Tsao, 1964), Schizothorax lissolabiatus (Tsao, 1964) and Schizopygopsis anteroventris (Wu & Tsao, 1989), from the Tibet reach of the Lancang River, China (N 29°06′–31°30′, E 96°57′–98°38′). Specimens were collected in April and September 2017. The specimens were caught with drifting gillnets (mesh size 2.5 cm and 7.0 cm). The b values of these three fish species ranged from 2.974 to 3.075. The high r² values (all > .980) indicate that these relationships will be appropriate for use in fisheries management of these species.     

Length‐weight relationships of four fish species from mangrove of Zhanjiang,China

Length‐weight relationships were determined for four fish species [Acentrogobius viridipunctatus (Valenciennes, 1837); Acentrogobius caninus (Valenciennes, 1837); Glossogobius olivaceus (Temminck & Schlegel, 1845); and Lutjanus ophuysenii (Bleeker, 1860)] belonging to two families. Samples were collected from 2002 to 2010 by cage net (50 × 15 × 15 cm, mesh size 0.5 cm) from Zhanjiang mangrove in China (20°36′N; 110°54′E). The total length ranged is between 2.3 and 18.1 cm and weighted between 0.3 and 90.2 g. The allometric coefficient (b) of length‐weight relationship varied from 2.72 for Zenarchopterus buffonis to 3.48 for Acentrogobius viridipunctatus. Length‐weight relationships for these four fish species were determined for the first time.     

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 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 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 relationships of three caught flatfish using shrimp trawler in Motaf fishing grounds,Bushehr province (Persian Gulf)

This study provides length–weight relationships (LWRs) for three flatfish species: Cynoglossus bilineatus (Lacepède, 1802), Solea elongata (Day, 1877), and Pseudorhombus elevatus (Ogilby, 1912) from Motaf fishing grounds (latitude 27°00′ to 28°03′N; longitude 51°41′ to 52°11′E), Bushehr province, Iran. A total of 103 fish specimens were collected using shrimp trawler with 40 mm (stretched mesh size) at depths of 10–30 m between August and September 2017. The LWRs for fish species were W = 0.0019L^3.353 for C. bilineatus: W = 0.0093L^3.174 for S. elongata, and W = 0.006L^3.181 for P. elevatus, respectively.     

Length–weight relationships for Eutropiichthys murius (Hamilton, 1822), Coilia reynaldi Valenciennes, 1848 and Johnius gangeticus Talwar, 1991 from lower stretch of the River Ganga,India

Length‐weight relationships (LWRs) for three fish species from the River Ganga (India) is presented. Sampling was conducted from the lower stretch of the River Ganga (Patna: 25°36′51.66″N & 85°12′7.02″E to Freserganj: 21°35′40.58″N & 88°15′28.92″E) during April, June and September and December of 2017. Specimens were caught using gill nets (18 nos.; mesh 18–32 mm), and bag nets (3 nos.; mesh 14–22 mm). The values a and b from LWRs ‐were found to be 0.007 and 2.977 for Eutropiichthys murius; 0.003 and 3.001 for Coilia reynaldi; 0.009 and 3.010 for Johnius gangeticus.     

Length–weight relationships for four fish species from lower stretch of River Ganga,India

Length‐weight relationships (LWRs) for four fish species from the River Ganga (India) is presented. Sampling was conducted in the lower stretch of the river (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) on tri‐monthly basis from September 2016 to December 2017. Specimens were caught in gill nets (mesh, 18–68 mm), cast nets (mesh, 12–14 mm), seine nets (mesh, 12–14 mm) and various traditional traps those were put over night and lifted in early morning. Total length and wet body weight of fish were measured to the nearest 0.1 cm and 0.01 g by a digital caliper and electronic balance respectively. From LWRs, the estimated b values were found to be 2.88 (Pisodonophis boro) to 3.17 (Gagata sexualis) whereas a value ranged from 0.001 (Pisodonophis boro) to 0.009 (Botia lohachata). As per FishBase, the species Gagata sexualis and Botia lohachata had new TLmax reported for LWR estimation.     

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 for five fish species from the middle reaches of the Yangtze River,China

Length–weight relationships (LWRs) for five fish species which were captured by trap‐nets and gillnets (major mesh size: 1–10 cm) from the middle Yangtze River, China (29°47′ – 29°26′N; 112°51′ – 113°08′E) were determined in September 2017. These were Acheilognathus hypselonotus (Bleeker, 1871), Culter oxycephaloides Kreyenberg & Pappenheim, 1908, Distoechodon tumirostris Peters, 1881, Sarcocheilichthys nigripinnis (Günther, 1873) and Micropercops swinhonis (Günther, 1873). The LWRs were estimated using the logarithmic form of the formula W  =  a  ×  L^b. The b value ranged from 2.879 for A. hypselonotus to 3.285 for M. swinhonis. LWRs for four fish species and new maximum lengths for three species are presented to FishBase for the first time.     

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 relationship of three Cynoglossus species (C. puncticeps,C. lingua and C. lida) from Chilika lagoon,India

The present study provides length–weight relationship (LWR) of three fish species, Cynoglossus puncticeps (Richardson, 1846), Cynoglossus lingua Hamilton, 1822 and Cynoglossus lida (Bleeker, 1851) of family Cynoglossidae from Chilika lagoon (19°28′–19°54′N; 85°05′–85°38′E), India. A total of 147 specimens were sampled during March, July and October of 2017 from screen barrier nets (mesh 14 mm to 26 mm) locally called khonda jal operated by local fishermen. The estimated b values derived from the data sets as follows: 3.12 for C. puncticeps, 3.09 for C. lida, and 2.88 for C. lingua.     

Length‐weight relationship models of two tropical shads,Tenualosa macrura (Bleeker, 1852) and Tenualosa toli (Valenciennes, 1847) in the coastal waters of Sarawak,Malaysia

This study investigates length‐weight and length‐length relationships of two species of the tropical shads, Tenualosa macrura (Bleeker, 1852) and Tenualosa toli (Valenciennes, 1847) collected from the coastal waters of Sadong (1°30′59.4”N and 110°44′46.4”E) and Sebuyau (1°31′26.8”N and 110°58′05.8”E), Sarawak, Malaysia. The fish were captured using gill nets (mesh size range 5–12 cm) operated by mechanized boat along the coast of Sadong and Sebuyau, Sarawak. Relative growth coefficient (b) was 2.942 and 3.408 for males and females of T. macrura while 2.909 and 3.178 for males and females of T. toli. All LWRs were significant (p < .05) between sexes for both species with the coefficient of determination (R²) ranging from .85 to .99. This report provides the reference of length weight relationship (LWR) models for the two species in their range of distribution.     

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 relationships for nine fish species in the Three Gorges Reservoir

Length‐weight relationships (LWRs) were determined for nine fish species occurring in the Three Gorges Reservoir(28°56′–31°44′N, 106°14′–111°28′E). Fish were collected using gill nets, including two of 1.0 m depth, 100 m long, and mesh size of 0.5 cm; two of 1.0 m deepth, 150 m long, and mesh size of 2.0 cm; and one of 1.5 m deepth, 100 m long, and mesh size of 6.0 cm. Gill nets were set over night including different habitats (riffles and pools, vegetated and non vegetated zones) from seven sites seasonally from January 2014 to January 2018. The first LWR reference for Jinshaia abbreviata (Günther, 1892), and Triplophysa tanggulaensis (Zhu, 1982) and new maximum lengths for other seven species are provided when comparing with records given in the international electronic databank FishBase (Froese & Pauly, FishBase. World Wide Web electronic publication, 2018).     

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 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).     

Relationships between opercula girth, maximum girth and total length of fish species caught in gillnet and trammel net selectivity surveys off the Portuguese coast

The relationships of total length (L_t) to girth at opercula (G_ope) and maximum girths (G_max) were estimated for 39 and 22 fish species, respectively, captured off the Portuguese coast between Póvoa do Varzim and Santo André (38°05′54′′–41°15′36′′N and 8°46′54′′–9°31′13′′W). The data were collected between April 1994 and September 1995. The best‐represented family was Sparidae (five species), followed by Soleidae and Triglidae (four species each). G_ope and G_max were found to increase linearly with length for all species, all r² values being statistically significant (P < 0.01) and higher than 0.81. When G_ope and G_max were plotted against length for all species combined, three groups were identified, corresponding to general girth–length relationships: G1 = 1.408 + 0.238 ×L_t, G2 = 2.455 + 0.328 × L_t and G3 = ?0.72 + 0.60 × L_t for opercula girth and G1 = 3.402 + 0.195 × L_t, G2 = 2.211 + 0.374 × L_t and G3 = ‐2.514 + 0.717 × L_t for maximum girth. These groups correspond to different body shapes of fishes: G1‐round, G2‐torpedo‐form and G3‐compressed body.     

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.