Length-weight relationships of six fish species from the Xiangjiang River in Guangxi region,China

This study aimed to estimate the parameters of length-weight relationships (LWRs) for six freshwater fish species that inhabit in the Xiangjiang River of Guangxi region, China. The specimens were sampled in April, July, and October 2014 and in January 2015 using electrofishing (CWB-2000P, China; 12 V import, 250 V export) and traps (mesh size 8.5 mm; length 200 m) at five sampling sites. For each sampling site, a trap was settled on one nearshore zone of the river for 24 hr, and the electrofishing was applied within 30 min from downstream to upstream with 200 m long. Standard length was measured (be accurate to 0.1 cm) and total weight determined (be accurate to 0.1 g) after preservation in formaldehyde (10%). The values for the parameter b of the length-weight relationships were estimated together with the coefficient of determination scores. In addition, this study provides a new tentative LWRs for the six species.     

Length-weight relationships of eight fish from seagrass meadows in Wenchang,China

The length-weight relationships (LWRs) were studied for eight seagrass fish from Wenchang, China, using gill nets (150*1 m, mesh size 0.5 cm), including Gerres oblongus, Ambassis kopsii, Halichoeres nigrescens, Sillago aeolus, Yongeichthys criniger, Oxyurichthys tentacularis, Lethrinus haematopterus and Hypoatherina tsurugae, in November 2017, March and August 2018. Results suggest that mean LWR parameters b for these eight seagrass fish varied from 2.801 for L. haematopterus to 3.640 for A. kopsii, and r² valued from .950 for L. haematopterus to 0.993 for H. nigrescens. This study will help us to better understand the ecological parameters these seagrass fish.     

Length-weight relationships of four fish species from the lower reaches of the Nujiang River and its tributaries in China

As one of the largest Southeast Asian rivers, flowing through China, Myanmar, and Thailand, the Nujiang (Salween) River contains a unique and rich diversity of fish species. In the present study, we investigated the length–weight relationships (LWRs) of four fish species (Pteronemacheilus meridionalis, Devario shanensis, Exostoma gaoligongense, and Glyptothorax granosus) collected from the lower reaches of the Nujiang River and its tributaries (24.175N~25.842N, 98.861E~98.903E), including the Mengboluo, Kungong, Luomingba and Laowo rivers in southwest China. Specimens were collected by using drift gill nets (100 m length × 1.5 m depth or 3 m depth, mesh-size: 1 cm-5 cm), cast nets (6.5 m, mouth opening: 35 × 45 cm², mesh-size: 4 mm) , and an electric shocker apparatus (12 V, 200 Hz) from different regions in the Nujiang River basin in September and October 2019 and June and September 2020. Before the collected fishes were placed in formalin, standard length (SL) and net weight (W) were measured respectively to the nearest 0.1 cm and 0.1g, respectively. Based on searches of the FishBase database and other relevant scientific literature, this study provides a new record of maximum size for P. meridionalis and LWRs for the four fish species.     

Length-weight relationships of 37 freshwater fish species from the Lefini river,middle Congo River basin (Republic of the Congo)

The present study reports on length-weight relationships (LWRs) for 37 of the most abundant fish species in the Lefini River basin, one of the largest right bank tributaries of the Congo River in the Republic of the Congo. The study area comprised 12 stations along 103 km of the river. Each station was sampled during March 2007 to August 2008 following standardized methods utilizing five monofilament gill nets of 10, 12, 15, 20 and 30 mm mesh size. Sample size, lengths, weights, LWRs, 95% confidence intervals of a and b, coefficient of correlation r² and growth type are provided for each species. Values of allometric coefficient b of the LWRs (W = aSL^b) ranged from 2.556 for Synodontis nigriventris to 3.363 for Brycinus poptae. These results represent the first study of length-weight relationships for fish species in a large affluent of the Congo basin as a whole.     

Length-weight and length-length relationships of three fish species from the Qingshui River in Guizhou province,Southwest China

The present study describes the length-weight (LWR) and length-length (LLR) relationships for three indigenous fish species from the Qingshui River, southwestern China. Fishes were collected by electrofishing in May 2015 in the middle Qingshui River. Total length (TL), standard length (SL) and fork length (FL) were measured to the nearest 0.1 cm with a digital calliper and weight (W) was determined with an electronic balance to an accuracy of 0.01 g. In addition, provides a new maximum total length for two species.     

Length-weight relationships of seven fish species from tidepools of an intertidal rocky shore in the Gulf of Cadiz,Spain (NE Atlantic)

Length-weight relationships for seven fish species caught from tidepools in an intertidal rocky shore in the Gulf of Cadiz are presented. Fish were sampled monthly (April 2008–January 2012), using hand nets (mesh size 1.5 mm). The values of b parameter remained within the expected range of 2.5–3.5 for all fish species. An ANCOVA test was used to evaluate differences in the b growth parameter between females and males. Gobius cobitis, G. incognitus and G. paganellus showed significant differences in the parameters of the length-weight relationships according to the sex.     

Length-weight relationships of eight fish species from the Hailang river,China

The present study reports the length-weight relationships (LWRs) for eight fish species sampled in Hailang River, a left-bank tributary of the Mudan River in Northeast China. The fishes were collected from April to October bimonthly 2017 by electrofishing (fishing 2 kilometers along the river and within 5 meters from the bank) and netting (drift gillnet: mesh size 2 cm × 3 cm; 200 m net length). The specimens were weighed (nearest 0.1 g) and measured (nearest 0.1 cm) in the laboratory. This study provides an update in maximum lengths for five species.     

Length-weight relationships of four fish species from the Hei River in northwest China

Length-weight relationships (LWRs) were assessed from four fish species in Hei River in northwest China. All specimens were collected using (fishing1 km along the river and 3 meters along the river bank) and netting (gill nets, nets: 30 × 1.2 m; mesh size: 3 × 3 cm) and shrimp cages (nets: 20.0 × 0.5 × 0.4m; mesh size: 0.5 cm) seasonally from April 2019 to October 2020. The gill nets and shrimp cages were soaked in water in the afternoon and pulled in around 10 a.m. the next day after an overnight stay. These specimens were measured for total length (L, 0.1 cm) and body weight (W, 0.1 g) while the specimens were fresh. The parameters for the LWRs were estimated with the basic statistical analyses. The study provided the new maximum total length for Gymnocypris chilianensis (21.0 cm) and Triplophysa tenuis (17.0 cm).     

Length-weight relationships of six Nemacheilid fish species (Teleostei: Cypriniformes) from different rivers of Manipur,India

The length-weight relationships (LWRs) of six Nemacheilid species (Schistura chindwinica, S. fasciata, S. khugae, S. minuta, S. reticulata and S. rubrimaculata) have been analyzed. Fish samples were collected on quarterly basis from March 2018 to February 2019. Sampling was performed using cast nets (mesh size 5–10 mm; about 50 sq m area covered each time and water depth was 4 ft approx.), and electrofishing (Ultrasonic Inverter Electro Fisher, 24 volts, 4 m) in the day time. The total length (TL) of individual fish was measured to 0.1 cm with a digital caliper and body weights (BW) were measured to 0.001 g with digital electronic balances. The parameters for the LWR equations were calculated, and the respective statistics such as the 95% confidence interval for parameters “a” and “b” are provided as well as the coefficient of correlation. For five species a new maximum total length has been documented.     

Length-weight relationships of six fish species of tropical lake,Mexico

The length–weight relationships (LWRs) for six native fish species from the Chapala Lake, Mexico, are described in this paper. The fish were caught monthly with the support of local fishermen from different landing sites. The daily catch is obtained using the nasa charalera (pot) and the gill net. Each fisherman can operate 20 pots daily at each fishing site for approximately six or seven months; this pot is a 2 m long cylinder, 0.5 m in diameter, with a mesh opening of 0.5 to 1 cm. Also, each fisherman can set between 10 and 20 gill nets each day at sunset and recover them in the morning, again for six or seven months. The length of the gill net is 30 m or more with a 2 m drop, with a 1 cm mesh size. The study provides basic data, morphometric data on length and weight of native species belonging to the genus Chirostoma. These species are of great importance for the local fishery with the Mesa Central of Mexico.     

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 relationships of 6 fish species caught in a Mediterranean lake (Trichonis-NW Greece)

In the present study the length–weight relationships (LWRs) of 6 fish species which are endemic to Western Greece, caught in the natural Lake Trichonis by experimental gillnets and electrofishing were estimated. Benthic (mesh size 5–55 mm; height 1.5 m; length 30 m) and pelagic (mesh size 6.25–55 mm; height 6 m; length 27.5 m) Nordic type multimesh gillnets were used seasonally, between February 2019 and November 2019, at different depth zones (0-57m). Electrofishing (80 Hz) conducted in the littoral zone of the lake during four samplings (2018, 2019). All the estimated LWRs were highly significant (p < .05) with high correlation coefficient (r² ≥ 0.962). The estimated b values ranged from 3.058 to 3.344. For five of the studied species (Trichonis spined loach (Cobitis trichonica Stephanidis 1974), Trichonis blenny (Salaria economidisi Kottelat 2004), Trichonis rudd (Scardinius acarnanicus Economidis 1991), Acheloos roach (Leucos panosi (Bogutskaya & Iliadou 2006)) , Hellenic minnowroach (Tropidophoxinellus hellenicus (Stephanidis 1971)) new maximum total body lengths (TL) were recorded, while for two species (T. hellenicus and L. panosi) LWRs are presented for the first time.     

Length-weight relationships of three Clupeiformes species from the Southeast coast of India,Bay of Bengal,Eastern Indian Ocean

This study deals with the length-weight relationships (LWRs) of three commercially important marine fishes belonging to the family Clupeidae from the major landing centers in Tuticorin, Mandapam, Thondi, Nagapattinam and Chennai in southeast coast of India. Monthly sampling were done at the respected landing centers from June, 2018 to April, 2019 from the commercial trawlers (with cod-end mesh size of 25–35 mm) and gill netters (with different mesh size vary from 20 to 170 mm). The estimated ‘b’ values ranged from 3.1215 (Sardinella albella) to 3.1819 (Amblygaster clupeoides) and ‘a’ values varied from 0.0059 (A. clupeoides) to 0.0074 (S. albella). The study also provides a new maximum total length (TL_max) for two species A. clupeoides and Sardinella fimbriata.     

Length-weight relationships of four fish species from the Yalong River,China

Parameters of the length-weight relationship (LWR) were estimated for four fish species [Beaufortia szechuanensis (Fang, 1930), Claea dabryi (Sauvage, 1874), Percocypris pingi (Tchang, 1930), and Yunnanilus sichuanensis Ding, 1995] from the Yalong River. Samples were collected seasonally from June 2018 to July 2019, using various fishing gears [set nets (mesh: 1.5 × 2.0 cm), hook, drift gill nets (three mesh sizes: 1.0; 2.0; 3.0 cm) and electro fishing]. Two new maximum standard length were recorded for C. dabryi and P. pingi.     

Length-weight relationships of eleven fish species captured in 18 streams of the Capim River basin,Brazil

The length-weight relationship is important for the study of populational dynamics. This study aimed to describe the length-weight relationships (LWR) of 11 fish species sampled on 18 streams of the Capim river basin on eastern Amazon. Specimens were captured in 2014, 2015 and 2017, using sieve nets with 2 mm of mesh size. Fixed specimens were fixed in 10% formalin and conserved in alcohol 70%, measured for standard length (SL, 0.1 cm) and total weight (W, 0.01 g). The 11 species analysed were: Hemigrammus bellottii, Hemigrammus ocellifer, Hyphessobrycon heterorhabdus, Iguanodectes rachovii, Copella arnoldi, Nannostomus trifasciatus, Apistogramma regani, Apistogramma agassizii, Gymnorhamphichthys rondoni, Hypopygus lepturus, Anablepsoides urophthalmus.     

Length-weight and length-length relationships of three fish species from the lower Yalong River,China

Length-weight relationships (LWRs) and length-length relationships (LLRs) were evaluated for three endemic fish species sampled from the lower Yalong River and its biggest tributary (the Anning River), in China. Specimens were captured using set gillnet (mesh size 4 cm) and backpack electro-fishing (power output 400 W, depth fished 1 m, area covered 3 m²) from June to July 2018. LWRs and LLRs are presented for the following species (Sinogastromyzon sichangensis, Micropercops swinhonis and Percocypris pingi).     

Length-weight relationships of 10 fish species from the coastal waters of the East China Sea

The present study provides the length-weight relationships (LWRs) for 10 marine fish species collected from the coastal waters of the East China Sea by bottom trawl surveys. The open width of the sampling net was 40 m and the mesh size of the codend was 20 mm. Specimens were collected from November 2015 to November 2019 at seasonal intervals. The measurement accuracy of weight and length were 0.1 grams and 0.1 centimeters, respectively. This study provides new information of LWRs for nine species which have not yet been reported in FishBase. Also, this study updates the information of maximum length for two species.     

Length-weight relationships of seven fish species from the laguna del cisne basin (Canelones,Uruguay)

This work provides new length-weight information for seven species of freshwater fishes. The analyzed specimens were collected monthly during a year (April 2018–March 2019) in a coastal lagoon system and its associated streams in southern Uruguay. During each sampling campaign, fishes were captured using gillnets in the lagoon and electrofishing in the streams. This study reports a new maximum size for four species and the first length-weight relationship report for Gymnogeophagus terrapurpura. Length-weight estimates and their confidence intervals are provided for all species.     

Length-weight relationships for 15 fish species in the East China Sea mainly captured by the commercial fishery and subelemented by survey samples

Length-weight relationships (LWRs) were presented for 15 fish species which caught in the East China Sea during 2009–2014. All of the samples were caught by commercial and scientific survey bottom trawl vessels. The commercial fishery survey used one-single bottom trawl with the smallest mesh size 25 cm and light seine fishing with the smallest mesh size 38 cm, however, the scientific survey only used one-single bottom trawl with the smallest mesh size 20 cm. The length and weight of all the fish were measured to the nearest millimeter and milligram, respectively. The application of these estimated values should be limited to the studied waters and observed length ranges. The development and adoption of a standardized sampling format for all studies aiming to determine LWRs should be undertaken.     

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.