Length–weight relationships of three small indigenous fish species from the Lower Brahmaputra,India

Length–weight relationships (LWRs) for three small indigenous fish species from the lower Brahmaputra in Assam, India: Glyptothorax telchitta, Nangra assamensis, and Gudusia chapra were studied on a monthly basis from February 2015 to January 2016. Various fishing gear types were employed: cast nets (9′ ½”), gillnets (30 × 0.9 m, 0.5″; 60 × 3 m, 1.5″) and mosquito nets (20 × 6 m, 0.04″). No previous reference is available on LWR data for two of these species.     

Length-weight relationships of five fish species from Brazilian Amazon coast hotspot estuaries

The length-weight relationships (LWR) were estimated for five fish species from the Golfão Maranhense, Brazilian Amazon littoral region. Samplings were performed in August 2016, during the dry season, using trawl net with 6.0 m length by 3.0 m width (trawl mouth opening of 6.0 m²) and 1.0 cm mesh size between opposite knots. This study registers LWR for Anchoviella elongata and Gobioides broussonnetii and the estimated LWR for Aspredo aspredo and Aspredinichthys filamentosus covers a wider size range. Moreover, it is presented maximum length values for A. elongata and Sphoeroides greeleyi.     

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.     

Length–weight relationships of 11 deep‐sea fishes from the western Bay of Bengal and Andaman waters,India

Length–weight relationships (LWRs) are presented for 11 deep‐sea fishes caught in the western Bay of Bengal and Andaman waters during August 2010 using a 38 m high speed demersal trawl II (HSDT II, crustacean version, codend mesh size 40 mm) and a 45.6 m Expo model demersal trawl (codend mesh size 30 mm). The b values ranged from 2.34 to 3.3 and the coefficient of variation (r²) ranged from .82 to .98. LWR estimates of eight deep‐sea fishes are provided for the first time. The estimated LWR values were compared with the Bayesian LWR estimates available in FishBase, based on models developed to improve the accuracy and predictability of species‐specific growth parameters of data‐poor species.     

Length–weight relationships of three demersal fish species caught from the eastern region of Java Sea,Indonesia

Length–weight relationship (LWR) parameters were determined for three demersal fish species Nuchequula gerreoides, Scarus scaber and Therapon theraps. The fishes were collected by seine net (the mesh size of wing: 12.70 cm, body: 3.81 cm, cod end: 2.54 cm, and total length of net: 20 m) in eastern region of Java Sea Indonesia during October 2016 – March 2017. The total length of these species (14.3 cm for N. gerreoides, 24.5 cm for S. scaber and 21.5 cm for T. theraps) were longer than previous studies. The b values of the LWR were 2.967 for N. gerreoides, 3.046 for S. scaber and 3.0475 for T. theraps.     

Salinity regulation of zooplanktonic abundance and vertical distribution in two saline meromictic lakes in south central British Columbia

Zooplankton species abundance and vertical distribution were followed in two south-central British Columbia saline meromictic lakes during the recent decade of their declining water levels. The lower salinity mixolimnion (0–7 m) of both lakes circulates partially most years down to their primary chemoclines marked by a 10–15 cm layer of purple sulfur bacteria (Amoebobacter purpureus) heavily grazed upon mainly by late copepodite stages and adults of Diaptomus connexus, possibly by some rotifers, but apparently not by cladocerans. Vertical distribution profiles, over an 8-year period, are presented mainly for the rotifer Brachionus plicatilis, two cladocerans Ceriodaphnia lacustris, and Daphnia pulicaria, as well as copepodite and adult D. connexus during normal periods of unimeromixis and a period of weak bimeromixis caused by shallow upper low salinity layers coming from drainage basin inputs.     

Length‐weight relationships of six native and one introduced species in small perennial watercourses of the Chocó region of Ecuador

This study estimated the length‐weight relationship (LWR) of seven species (six native species and one introduced species) in two small perennial watercourses of the Chocó region of Ecuador. Specimens were collected bimonthly with two different fishing methods between August 2016 and July 2017 (Seine net: 46 × 21.20 m, 3 mm mesh size and casting net: 2.10 m radius, 10 mm mesh size). This is the first report of the LWR and a new report on maximum length for two endemic species (Eretmobrycon ecuadorensis and Andinoacara blombergi). The intercept (a) of the LWR ranged from 0.0124 to 0.0316 and the slope (b) ranged from 3.03 and 3.16. The LWRs are useful and, in connection with the collection of other key data on fish biology and the environment they can contribute to management and conservation of the local inland fisheries.     

Length‐weight relationships of three fish species from the lower Brahmaputra drainage in Assam,India

Length‐Weight relationships (LWRs) for three Cyprinids (Chela cachius, Devario devario and Securicula gora) collected seasonally from May 2016 to January 2017 along the lower Brahmaputra drainage in Assam (Northeast India), using fishing gears [cast nets: 2.5 m, 10–15 mm mesh size; gillnets: 30 × 0.9 m, 18–20 mm mesh size], were estimated. The ‘b’ values of the LWR estimates ranged from 3.39 for C.  cachius, 3.14 for D.  devario, and 2.97 for S.  gora respectively.     

Length–weight relationships of six fish species from the headstream region of the Dongjiang River,China

Dongjiang River, a main tributary of the Pearl River, is geographically situated in South China. The present study describes the length–weight relationships (LWRs) of six fish species (Acrossocheilus paradoxus, Barbodes semifasciolatus, Onychostoma elongatum, Microphysogobio fukiensis, Microphysogobio kiatingensis, Metzia lineata) from the headstream region of the river including five Chinese endemic species (A. paradoxus, B. semifasciolatu, O. elongatum, Mi. fukiensis, Mi. kiatingensis). Fish species of five genera of the same family were collected quarterly from April 2012 to October 2014 by using non‐selective fishing gears: drag nets (5 m, mesh‐size 3 cm), drift gillnets (30 × 15 m, mesh‐size 5 mm), fish cages (4 m, mouth opening 40 × 40 cm), scoop nets (mesh‐size 0.5‐1 cm), and electro‐fishing (12V, 200 Hz). The parameter a and b in the LWR equations (W = a L^b) ranged from 0.0014 to 0.0228, and 2.89 to 3.18, respectively. Compared with FishBase, this study provides the first LWR records for four cyprinids (A. paradoxus, B. semifasciolatu, O. elongatum, Me. lineata) and a new record of maximum body length for O. elongatum.     

Length–weight relationship of five coral reef fish from the Weizhou Island,China

In the present study, the LWRs investigations were conducted for five fish species from Weizhou Island for four times seasonally during the period from April 2017 to January 2018. Samples were obtained using gillnets (25 × 12 m, mesh size 0.5 cm), trawl nets (50 × 12 m, mesh size 0.5 cm) and fishhooks (0.5 × 0.5 × 10 m, mesh size 0.5 cm mesh). Results indicate that mean LWR parameters b for these five coral reef fish varied from 2.847 to 3.525 and r² values varied from 0.972 to 0.988.     

Length–weight relationships of four fish species from the upper Paraná River basin,Southeastern Brazil

Here the length–weight relationships (LWR, hereafter) of Pareiorhina pelicicei, Trichomycterus candidus, T. pirabitira, and T. piratymbara are provided. Samples of each species were collected between April and July 2017 with a hand net (1.5 mm mesh) in three sites from the upper Paraná River basin, Southeastern Brazil. These results increase knowledge about the LWR of Neotropical freshwater fish.     

Length‐weight relationships of 10 fish species found off Antalya Bay,eastern Mediterranean

Length–weight relationships (LWRs) are presented for eight teleost and two elasmobranch fish species representing ten families that were captured in deep water (from 400 to 1000 m, except for the stingray Dipturus centrura) in Antalya Bay. This study represents the first LWR references for eight of these species.     

Length‐weight relationships of three fishes from the Nujiang River,China

The length‐weight relationships (LWR) for three fish species collected from the Nujiang River, China, were determined. Fishes were caught quarterly by drift gill net (stretched mesh size: 4 cm, depth: 2–4 m) and cast net (mesh size 1 cm; depth: 1–2 m) from May 2016 to July 2017. The values of parameter b in the LWR equations were estimated as 2.69 for Balitora nujiangensis Zhang & Zheng, 1983, 2.80 for Glyptothorax deqinensis Mo & Chu, 1986 and 2.94 for Pseudexostoma brachysoma Chu, 1979, respectively.     

Length-Weight Relationships for freshwater fishes from streams of the Atlantic Rainforest,State of Paraná, Brazil

This study reports the Length-Weight Relationships (LWR) for 10 freshwater fish species sampled in the Atlantic Rainforest, Southern Brazil. Sampling was conducted between 2016 and 2017, in nine streams, using electrofishing. Collected fishes were fixed in formalin, and thus some shrinking was unavoidable. The values of parameter b of the LWR (W = aL^b) ranged between 2.5 and 3.5. We report for the first time the LWR for seven species: Geophagus iporanguensis, Isbrueckerichthys duseni, Hypostomus interruptus, Kronichthys lacerta, Chasmocranu lopezi, Astyanax lacustris e Neoplecostomus ribeirensis. We highlight the importance of the LWR data in supporting further studies on fish stocks and environment in the Atlantic Rainforest, thereby contributing to the database needed to develop fisheries management and maintenance of ecosystem services.     

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 12 marine fish species from the Pacific coast of Guatemala associated with small-scale fisheries

The length–weight relationships (LWRs) were estimated for 12 fish species. The species were collected monthly from the commercial catch of small-scale fisheries using gillnets (mesh size 7.6–15.2 cm, length 200–1,000 m, 6–48 hr of operation during the day) and longlines (surface and bottom, 300 hooks, sardine bait, operation during the day) in the period October 2017 to July 2018 along the Pacific coast of Guatemala. Most values for the parameter (b) of the length-weight equations were within the commonly expected range (2.50–3.50) except for two species: Bagre pinnimaculatus (2.22) and Menticirrhus panamensis (3.56). All values for the coefficient of determination (r²) were above .95 and thus the estimates can be considered reliable. Besides novel LWRs we provide for some species estimates which include a new TLmax not yet involved of any LWR studies.     

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 and length at first maturity for fish species in the upper Miranda River,southern Pantanal wetland,Brazil

Length–weight relationships (LWR) were estimated for 17 species and total length at first maturity (L50) for three species of freshwater fishes from the Miranda River, southern Pantanal, Brazil. The b values were compared for some species in the Paraguay River basin with the northern (Cuiabá River) part of the basin; differences in length–weight relationships were significantly different for Pseudoplatystoma corruscans, P. reticulatum (syn. P. fasciatum). First references on L50 and LWR are presented for two and eight fish species, respectively, as well as the new maximum total length for two species.     

Length‐weight and length‐length relationships of two gobiid fishes Eleotris fusca (Forster, 1801) and Odontamblyopus rubicundus (Hamilton, 1822) from the Payra River,southern Bangladesh

The present study provides the estimates of length‐weight relationships (LWRs) and length‐length relationships (LLRs) of two gobiid fishes Eleotris fusca and Odontamblyopus rubicundus from the Payra River, southern Bangladesh. Fish samples were collected from the set bagnet (mesh size <2 mm) fishers of the Payra River in July 2016. Allometric coefficient (b) values were 2.95 for E. fusca and 2.76 for O. rubicundus. Additionally, the LLRs were highly significant with r² ≥ .955. While the estimate of the LWR for O. rubicundus includes a substantial larger sample size and thus provides a more reliable LWR than the one published so far, the LWR for E. fusca must be considered as tentative because the sample includes only juveniles for a fish that reaches a maximum standard length more than three times as much. Additional studies are needed to further improve our LWR knowledge base for these fish species.