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 relationships of six fish species from the Zengqu River and the Ouqu River,southwest China

This study provides the first report of length–weight relationships (LWRs) for six endemic fish species collected from the Zengqu River and the Ouqu River, two of the tributaries to the upper reaches of the Jinsha River, southwest China. Samples were obtained in May 2013 and September 2013 using various types of fishing gear. A total of 413 specimens belonging to six fish species were analyzed; their LWRs were W = 0.0069L^3.086 (r² = 0.987) for Schizothorax wangchiachii (Fang, 1936), W = 0.0076L^3.029 (r² = 0.980) for Schizothorax dolichonema (Herzenstein, 1889), W = 0.0029L^3.315 (r² = 0.961) for Schizopygopsis malacanthus (Herzenstein, 1891), W = 0.0082L ^2.970 (r² = 0.950) for Ptychobarbus kaznakovi (Nikolsky, 1903), W = 0.0017L^3.464 (r² = 0.957) for Triplophysa stolioczkae (Steindachner, 1866), and W = 0.0037L ^3.190 (r² = 0.956) for Triplophysa orientalis (Herzenstein, 1888). Prior to this study, the LWRs for S. dolichonema, P. kaznakovi and T. orientalis were unknown. In addition, new maximum sizes for four of the species are provided.     

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 relationships and growth parameters of two endemic fish species (Floridichthys polyommus Hubbs, 1936 and Fundulus persimilis Miller, 1955) from the Yucatan Peninsula,Mexico

This study reports length‐weight relationships and growth parameters for Floridichthys polyommus Hubbs, 1936 and Fundulus persimilis Miller, 1955 from La Carbonera, a karstic tropical coastal lagoon on the northwestern coast of the Yucatan Peninsula, Mexico. Specimens were collected between April 2009 and March 2010. The resulting length‐weight relationship for F. polyommus was: W = 0.0180 Lt^3.37 and W = 0.0142 Lt^3.35 for F. persimilis. This study presents the first estimation for both species of the von Bertalanffy growth model parameters, the growth performance index, the L₅₀, and is the first report of the length‐weight relationship for F. persimilis.     

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 relationships of 33 fish species from New Zealand

Length–weight relationships are presented for 33 fish species from New Zealand. The parameters a and b of the equation W = aL^b were estimated. Parameter b ranged from 2.51 (Pseudocaranx dentex) to 3.51 (Alepocephalus antipodianus) with a mean of 3.12 ± 0.24. Most of these estimates (90.9%) were between 2.8 and 3.4. Maximum lengths and depths of catch are updated for nine species.     

Length to weight ratio of four fish species in estuary areas in the Northeast region of Brazil

The length to weight ratio (LWR) was used to estimate populations of four fish species sampled on the Amazon coast of the state of Maranhão, Brazil. The fishes were sampled in 2018 and 2019 by artisanal coastal fishing, using gillnets (0.20–0.60 mm). The parameters a and b of the equation W_T = a L_T^b were estimated. The obtained LWRs were W_T = 0.06LT^2.93, (r²) = .989 for Oligoplites saliens; W_T = 0.061L_T^2.57, (r²) = .982 for Peprilus crenulatus; W_T = 0.014L_T^2.80, (r²) = .985 for Bagre bagre; and W_T = 0.035L_T^3.21, (r²) = .981 for Nebris microps.     

Biological parameters and current status of European eel (Anguilla anguilla Linnaeus, 1758) from Asi River,Northeastern Mediterranean region,Turkey

The biological characteristics of eels from the Asi River, Turkey, were assessed between December 2017 and November 2018. Eels were sampled monthly using fyke nets (operated by professional fishermen), yielding a total of 509 specimens. Total length and weight were measured, sex, age and maturity stages (silver or yellow eel) were determined. Catch Per Unit Effort (CPUE) was calculated for both biomass per unit effort and numbers caught on a monthly and annual basis. The length-weight relationships (LWRs) of silver and yellow eel was W = 0.009*TL^3.22 (n = 262) and W = 0.0106*L^3.09 (n = 247), respectively. The age of the sampled fish ranged from year class II to VI. Von Bertalanffy growth parameters were estimated as L_∞=69.25 cm, K = 0.43 1/year, t₀= −0.41 and phi prime index ( ǿ )= 3.31 for all samples. The overall eel fishing mortality rate (F) was 0.31 year^-1, and the exploitation and survival rates of silver stage eels were estimated with 30% and 39%, respectively.     

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.     

Growth characteristics of Uranoscopus scaber Linnaeus 1758, inhabiting the Iskenderun Bay (Northeastern Mediterranean)

This study aimed to determine the age and some growth characteristics of Atlantic stargazer (Uranoscopus scaber) from Iskenderun Bay (Northeastern Mediterranean). For this purpose, a total of 150 Atlantic stargazer ranging in size from 9.1 to 28.0 cm in total length (weight: 11.7–345.7 g) were collected as by-catch from a commercial trawl fishing boat at a depth of 80–100 m between May 2015 and January 2016. The bottom trawl gear used was equipped with a 44 mm stretched mesh size net at the cod-end. The percentage of females and males were 46.7% and 53.3% respectively. The total length–weight relationships equation with coefficient of determination (R²) were found as W = 0.011*TL^3.131, R² = .9728, for all individuals, W = 0.015*TL^3.021, R² = .9512 for females and W = 0.0102*TL^3.136, R² = .9553 for males. By using the von Bertalanffy equation, the growth parameters of Atlantic stargazer were estimated to be L_∞ = 42.35 cm, k = 0.098, t₀ = −1.8474 for all individuals; L_∞ = 36.92 cm, k = 0.138, t₀ = −1.2693 for females and L_∞ = 38.77 cm, k = 0.1, t₀ = −2.334 for males. In this study, age reading was done by two independent readers and index of average percentage error (IAPE) was calculated as 6.1%. The highest condition factor value calculated as 1.81 in the age group 6 and the lowest condition factor value was calculated as 1.48 in the age group 1.     

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 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 relationships of the silver European eel,Anguilla anguilla (Linnaeus, 1758), across its geographic range

Length–weight relationships for European silver eel (Anguilla anguilla) sub‐populations in six countries (13 catchments) along the latitudinal gradient in the area of distribution in this study use three important sampling programs; these results concur with previous studies on European eel with the equation: W = 0.0010 L^3.148 for the entire data set (sexes combined). Significant differences were observed among the 13 catchments, possibly implying differences in body condition. Male and female LWRs varied significantly between and among catchments, suggesting that the capacity of silver eels to migrate and reproduce successfully varies according to the sites.     

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.     

Age and growth of Schizopygopsis younghusbandi younghusbandi in the Yarlung Zangbo River in Tibet, China

Schizopygopsis younghusbandi younghusbandi is an endemic species whose distribution is restricted to the middle reaches of the Yarlung Zangbo River, being one of the most important commercial fishes in this area. Age and growth of 606 specimens captured between October 2002 and April 2005 were studied. The range in standard length (L) was 65.7–387.3 mm and total weight (W) was 3.3–772.0 g. The relationship between L and W was W = 0.000909L^2.2493 for males and W = 0.000259L^2.4781 for females. Age, determined from anal scales and lapillus otoliths, ranged from 3 to 18 years. The parameters of von Bertalanffy growth functions, estimated by back-calculated length, were L_￥ = 442.7mm  LL_\infty = 442.7mm\;L, k = 0.0738 year⁻¹ and t ₀  = −1.4 year for males, and L_￥ = 471.4mm  LL_\infty = 471.4mm\;L, k = 0.0789 year⁻¹ and t ₀ = 0.2 year for females. Males and females exhibited statistically significant differences in growth. χ ²-test indicated that von Bertalanffy growth functions could well describe the growth of S. y. younghusbandi. The longevities were 39.2 and 38.2 years for males and females, respectively. Growth inflexion points were 10.2 and 12.0 years for males and females, respectively, but 84.8% of the captures were at the smaller ages. So conservation and management schemes for this population should be considered urgently. In addition, we found that populations from the upstream of the Lhasa River, the downstream of the Lhasa River and the middle reaches of the Yarlung Zangbo River showed statistically significant differences in growth patterns.     

Length–weight relationship and biological information of the yellow snapper Lutjanus argentiventris from a tropical estuary: Río Caté, Gulf of Montijo,Panama

This paper reports length–weight relationships and summarizes data for Lutjanus argentiventris from Río Caté, a tropical estuary on the Gulf of Montijo, Pacific coast of Panama. The length–weight relationship obtained was W = 0.012Lt^3.07. The L. argentiventris mature throughout the year, although in fewer numbers from September to November. The sex ratio was 1 male to 0.9 female. Occurrence in stomachs showed that they feed mainly on crustaceans (75.4%), fishes (18.5%), polychaetes (4.6%), and molluscs (1.5%). Portunid crabs (Portunus asper) were the most frequent prey group.     

Age and growth of the blackchin guitarfish Glaucostegus cemiculus (Geoffroy Saint-Hilaire, 1817) from Iskenderun Bay (Northeastern Mediterranean)

Between September 2010 and June 2012, a total 291 (166 females and 125 males) blackchin guitarfish Glaucostegus cemiculus were captured by a commercial bottom trawler (F/V Coşkun Reis) in Iskenderun Bay, Turkey (northeastern Mediterranean Sea). The total length (L) and total weight (W) of the female and male guitarfish ranged between 32.0–165.0 cm and 88 g–16.68 kg, and 34.3–128.3 cm and 112 g–6.00 kg, respectively. Vertebral age estimates ranged from 0 to 8 years for females and 0 to 5 years for males. The growth models of von Bertanlanffy and Gompertz were fitted to the length at age data using the nonlinear regression method. Model selection was based on the values of the residual standard error and the Akaike's information criterion corrected for small sample size (AIC_C) associated with each fit. The von Bertalanffy growth model provided the best fitting growth curves for each sex with parameters reaching L_∞ = 187.17 cm, K = 0.195 year^-1, t₀ = −1.38 year for females, and L_∞ = 144.85 cm, K = 0.321 year^-1, t₀ = −1.13 year^-1 for males. The W–L relationship parameters did not differ significantly between sexes, the estimated values of a and b were 0.0018 and 3.11, respectively. By using these values of a and b, and also respective estimates of L_∞, the values of W_∞ were obtained as 20.53 kg for females and 9.25 kg for males. The overall percentage ratios of females and males in the samples were 57% and 43% respectively.     

Length–weight relationship of Hyporthodus haifensis and Mycteroperca rubra (Pisces; Serranidae) from the North‐Eastern Mediterranean Sea,Turkey

Length–weight relationships (LWRs) for Hyporthodus haifensis and Mycteroperca rubra were studied using longlines at depths of 5–150 m, in the Gulf of Antalya, northeastern Mediterranean Sea. Fishing operations were carried out daily with 15 fishing boats. A total of 170 individuals were sampled. The LWR relationships of Hyporthodus haifensis and Mycteroperca rubra were calculated as W = 0.009L^3.142 (r²) = 0.996 and W = 0.0081L^3.0652 (r²) = 0.989 P < 0.05, respectively.     

Larval rearing of fringe-lipped carp,Labeo fimbriatus (Bloch) with low cost diets including green bottle fly Lucilia sericata (Meigen) larvae meal incorporated diet

A study was conducted with non-conventional ingredients to test their efficacy as fishmeal (FM) replacers in the diet of fringe- lipped carp. Labeo fimbriatus first feeding larvae and fry were reared for 30 and 60 days in indoor, 50 L, aerated, circular plastic tanks at 100 and 30 numbers tank⁻¹, respectively. In the first feeding larvae to fry rearing experiment (Exp. 1), the fish were fed with either of the following isonitrogenous and isocaloric diets – live plankton, FM diet, green bottle fly (Lucilia sericata) larvae meal (GBFLM) diet and silkworm pupa (SWP) diet. The fry to fingerling rearing (Exp. 2), was also conducted using the same diets described above except live plankton. All compounded diets were formulated to contain 40% crude protein for the experiment 1 and 35% for experiment 2 and were fed ad libitum. Triplicate tanks were maintained for each treatment in both the experiments. In Exp. 1, the mean final weight of fry was higher with plankton and FM diets, while no difference (p > .05) was observed between FM and GBFLM diets. Weight of fish fed SWP diets was not statistically different from those fed GBFLM diet. No difference (p > .05) in final length, survival and condition factor was recorded. Analysis of digestive enzyme activity of whole fish revealed lower (p < .05) activity of amylase in fish fed plankton. In Exp. 2, no difference (p > .05) was observed between the different diet groups in terms of mean final weight, length, survival and condition factor. Analysis of digestive enzyme activity of whole fish revealed no difference (p > .05) in the activity of digestive enzymes between the treatments except a lower (p < .05) activity of trypsin in FM diet and lipase in FM and GBFLM diets. Since the survival and condition factors of animals is the most important aspect during nursery rearing, similar (p > .05) values recorded in different treatments indicate the possibility of incorporation of these non-conventional protein sources in the diet of L. fimbriatus during first feeding larvae to fry and fry to fingerling rearing.     

Length–weight relationships for two marine fish species from the Gulf of Oman: Uranoscopus guttatus Cuvier, 1829 and Lagocephalus inermis (Temminck & Schlegel, 1850)

This study presents the first report of length–weight relationships (LWRs) for Uranoscopus guttatus and Lagocephalus inermis from the Iranian coast on the Gulf of Oman. A wide range of body lengths and weights were obtained using samples from non‐selective trawling surveys. The LWRs obtained were W = 41.408L^3.519 and W = 16.525L^2.847 for U. guttatus and L. inermis, respectively.