Twenty‐eight additions to the length‐weight and length‐length relationships of Indo‐Pacific fishes from the Davao Gulf,Philippines

Selected fish were measured on markets along the Davao Gulf, Philippines between 2009 and 2016, augmenting the number of Length‐Weight relationships (LWR) published earlier for the same area. LWRs were calculated for 28 fishes including those of 12 firstly reported, rare species. SL‐TL and SL‐FL relationships were determined for 28 and 25 species (also including 8 and 12 newly reported relationships, respectively). Minimum size at which individuals start developing forked tails are provided for Cheilinus fasciatus (SL = 15.0 cm), Plectorhinchus polytaenia (SL = 27.0 cm), Pseudobalistes flavimarginatus (SL = 18.0 cm) and Thalassoma hardwicke (SL = 11.5 cm). The flatfish Psettodes erumei had a right‐left eyed ratio of 0.55.     

New length–weight relationships and Lmax values for fishes from the Southeastern Mediterranean Sea

Length–weight relationships (LWR) of fish serve as building blocks in ichthyology and fishery science. In this study LWR knowledge is extended to some species, regions and sizes of fish either incomplete or missing from the literature or from the online databank (FishBase). For several species data are presented for the first time, while other entries are improved and expanded. Organisms were captured by trawl from the continental shelf of the Israeli coast, where fishes were hypothesized as being small due to low productivity and high water temperatures – a phenomenon called ‘Levantine Nanism’. Despite this, for nine of the 43 species presented here the maximum length values exceeded their L_max in FishBase. The dominance of fishes of Indo‐Pacific origin among the species with exceptionally large specimens (7 of 9) is in agreement with Bergmann's rule; it is thus hypothesized here that these large specimens result from the low temperatures in the Mediterranean compared to their warm Indo‐Pacific sources. This is an example of the superb adaptation of tropical species to the Mediterranean and suggests that Levantine Nanism may be limited to indigenous species.     

Total length‐weight relationships among Thai freshwater fishes and the influence of capture location and preservation

Total length‐weight regressions on logarithmic transformed data are provided for 33 species, with 26 apparently being first estimates. All regressions are highly significant with slope values between 2.5720 and 3.4436. Slopes and intercepts of length‐weight regressions did not differ significantly with location for each of three species. Preservation in 10% formalin for 10 days followed by 30 days in 70% ethanol did not significantly influence regression slopes for the three species, length ranges and/or locations examined (ancova ). Significance among regression intercepts was equivocal with ancova analyses mostly suggestive of differences and overlap of 95% confidence limits mostly suggestive of similarities.     

Length–weight and length–length relationships for some Yangtze River fishes in Tian‐e‐zhou Oxbow,China

Length–weight and length–length relationships are reported for 32 fish species belonging to seven families and 26 genera from the Tian‐e‐zhou Oxbow in the middle reach of Yangtze River, near Shishou City, China. The weight (W) ‐ length (L) relationships were estimated using the logarithmic form of the equation W = aL^b. The exponent b varied from 2.60 to 3.65 (mean ± SE: 3.12 ± 0.25). The 14 weight–length relationships, 13 length–length relationships, and seven maximum lengths are presented to FishBase for the first time.     

Length–weight and length–length relationships for six commercial fishes from southern Korean waters

Presented are the relationships between total length and weight, and between total length and standard length for six commercial fishes collected twice a month from local fish markets in southern Korea between 2005–2006 for Acanthopagrus schlegelii (Bleeker, 1854), Hexagrammos agrammus (Temminck & Schlegel, 1843) and Hexagrammos otakii (Jordan & Starks, 1895), and monthly in 2004 for Dentex tumifrons (Temminck & Schlegel, 1843), Doederleinia berycoides (Hilgendorf, 1879) and Scomberomorus niphonius (Cuvier, 1832). The LWR for D. tumifrons is estimated for the first time, and a new maximum length was recorded for S. niphonius. All total length and weight relationships were significant (all r² > .953). The values of exponent b, estimated using simple linear least squares of log‐transformed weight and length data, ranged from 2.945 to 3.317.     

Length‐weight relationships for small Midwestern US fishes

Herein, we provide length‐weight relationships for juvenile and smallbodied freshwater fishes of 20 species. Length‐weight parameters were estimated using data collected through four years of electrofishing surveys conducted in the rivers of Illinois, USA.     

Length‐weight and length‐length relationships of three small indigenous fishes from the Payra River,southern Bangladesh

Length‐weight relationships (LWRs) and length‐length relationships (LLRs) for three small indigenous fishes (Esomus danrica, Pachypterus atherinoides and Salmostoma bacaila) were reported from the Payra River, southern Bangladesh. Samples were collected using traditional fishing gear including cast net (mesh size ranges from 1.0 to 2.0 cm), seine net (mesh size ranges from 1.5 to 2.5 cm) and square lift net (mesh size ~ 1.0 cm) in August to September 2017. Allometric coefficient (b) values were 2.66 for E. danrica, 3.08 for P. atherinoides and 3.06 for S. bacaila. The LLRs were also highly significant with r² ≥ .956.     

Length‐weight and length‐length relationships of four small fishes from the Atrai River,Dinajpur, Bangladesh

Length‐weight (LWRs) and length‐length relationships (LLRs) were determined for four fish species collected from the Atari River in Dinajpur of Bangladesh. Sampling took place monthly between January and June 2016, using seine nets of commercial fishermen (mesh size 4 mm). In LWRs (r² > .927, p < .05), slope (b) was estimated as 3.191, 2.992, 3.217 and 3.109 for Acanthocobitis botia, Botia lohachata, Canthophrys gongota and Chanda nama, respectively. In LLRs (r² > .812, p < .05), lengths i.e. TL, SL, HL and FL were highly correlated. The present study on these species would be the baseline for FishBase dataset.     

Length‐weight and length‐length relationships and form factor of three threatened fishes from the Ganges River (NW Bangladesh)

Data and information are needed to avert the alarming decline and initiate conservation measures for three threatened fishes, Labeo boga (Hamilton, 1822), Nandus nandus (Hamilton, 1822) and Puntius ticto (Hamilton, 1822), from the Ganges River and surrounding ecosystems. These fishes are decreasing rapidly due to high fishing pressures as well as environmental degradation. This study furnishes the length–weight relationships (LWRs), length–length relationships (LLRs) and form factor (a_3.0) of these three threatened species from the Ganges River, northwestern Bangladesh. A total of 773 specimens from the three species and two families used for this study were caught by traditional fishing gear between April 2011 and March 2012. The analysis of covariance (ancova ) revealed significant differences between the sexes in LWRs for L. boga (P < 0.001), but not with the remaining species (P > 0.05). Furthermore, the LLRs were highly correlated (r² > 0.983; P < 0.001), and ancova analyses additionally indicated that LLRs did not differ between sexes (P > 0.05). The calculated form factor (a_3.0) was 0.0111, 0.0159 and 0.0129 for L. boga, N. nandus and P. ticto, respectively. This study presents the first references on LWRs, LLRs and form factor for these three threatened species in Bangladesh. The results would be useful for further studies on the population assessment and sustainable conservation of the limited stocks in the Ganges River ecosystem.     

Length–weight and length–length relationships of three cyprinid fishes from the Bibi‐Sayyedan River,western Iran

This study describes the length–weight and length–length relationships for three cyprinid species from the Bibi‐Sayyedan River (western Isfahan provinces, Iran). The slope parameter (b) values in the length–weight relationship equations were determined as 3.0729 for Alburnus mossulensis Heckel, 1843; 2.8509 for Barbus lacerta Heckel, 1843; and 3.0864 for Chondrostoma regium (Heckel, 1843). This study presents the first LWR and LLR references for these species in the Bibi‐Sayyedan River.     

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).     

Composition and length‐weight relationships of fish species in Lake Erhai,southwestern China

Length–weight relationships (LWRs) are described for 23 fish species (five indigenous species and 18 exotic species) in Lake Erhai, a plateau deep lake located in southwestern China. Four different types of fishing gear were used in order to include all possible length ranges from 2009 to 2012. Results show that the exponent b ranged from 2.72 to 3.79. The length of the growth inflection point between juveniles and females of Pseudorasbora parva and Micropercops swinhonis coincides with the length at which 50% of the females are sexually mature, respectively. The LWRs of P. parva and M. swinhonis are affected by sexual dimorphism, and Hemiculter leucisculus shows significant differences between juveniles and females. In addition, the first LWR records for nine species are provided in this study.     

Length–weight and length–length relationships of three Ambassid fishes from the Ganges River (NW Bangladesh)

Length–weight relationships (LWRs) and length–length relationships (LLRs) are presented for the first time for three Ambassid fish species from the Ganges River, northwestern (NW) Bangladesh. Fish were sampled with traditional fishing gear including cast net (mesh size ranges from 1.0 to 2.0 cm), gill net (mesh size ranges from 1.5 to 2.5 cm), square lift net (mesh size ~ 1.0 cm) and conical and box trap, October 2014 to September 2015. Allometric coefficient (b) values were 3.00 for Chanda nama, 3.10 for Parambassis lala and 3.23 for Parambassis ranga, respectively. Additionally, the LLRs were highly significant with r² ≥ .958. The present observations would be an effective tool for their stock assessment in the Ganges River, NW Bangladesh and surrounding ecosystems.     

Length‐weight and length‐length relationships of three indigenous fish species in Persian Gulf,Iran

In this study, length‐length relationships (LLRs) and weight‐length relationships (WLRs) were established for a Carangidae species: Uraspis helvola and tow Flatfishes: Pseudorhombus elevatus and Psettodes erumei that are substantial marine fish species to commercial fisheries in Persian Gulf that are indigenous marine fish species in the region. Samples were collected by non‐selective fish bottom trawler with stretch mesh size of 4 centimeters at the cod‐end area, which helped us to obtain such a broad range size that included small, medium and large size classes during June to August 2017. Hitherto, the length‐weight model presented in this study for Pseudorhombus elevatus and Uraspis helvola were not documented on Fishbase. Additionally, new records of maximum length are presented as 64.5 and 30 centimeters for P. erumei and P. elevatus respectively. A comprehensive size distribution and highly significant fitted model (r²>0.95) in this research provides useful insight for future studies on fish biology, fisheries assessment and ecological modeling.     

Length‐weight relationships of fishes in the Mira basin,Colombia

This study estimated the a and b parameters of the length–weight relationships of 15 fishes from the Mira and Caunapí rivers, San Andrés de Tumaco, Nariño, Colombia. The specimens were captured during four samplings periods between 2015 and 2016 using a different a combination of fishing gillnets and electrofishing. The a values ranged from 0.0002 to 0.04 and b values ranged from 2.86 to 3.6. The data presented here are tentative estimates because the fish have been weighted and measured after fixation in formalin and ethanol, however, these data are references for weight‐length relationship for 15 species, the maximum weight for the same 15, and new maximum lengths for 3 species.     

Length–weight relationships for estuarine fishes in South Brazil

The present study reports the length‐weight relationships (LWRs) for 18 estuarine species sampled in Guaratuba Bay, South Brazil. For the majority of these 18 species the LWRs are known from the literature, but these estimates do not consider sexes separately which is done in this contribution. Different fishing gears were used in the samplings (cylindrical nets – 1 mm mesh size, bottom trawls – 250 mm mesh size in the arms and 12 mm mesh size in the bag, beach seine – 5 mm mesh size and hook and line fishery) between September 2007 to April 2014. The specimens were sexed and the LWRs were calculated for each sex separately. There were differences between sexes in growth type, showing the importance of sexing in these studies. We reported for the first time (based on FishBase) the LWRs for two species: Ctenogobius shufeldti and Hypleurochilus fissicornis.     

Length‐weight and length‐length relationships of four Alosa species along the southern Caspian Sea coast

This study investigates length‐weight and length‐length relationships of four shad species (Alosa braschnikowi, Alosa caspia, Alosa kessleri, and Alosa saposchnikowii) captured on the southern Caspian Sea coast of Iran. The relationship of total length (TL), fork length (FL) and standard length (SL) and the relationship between total length and body weight are presented.     

Length–weight and length–length relationships of three ecologically important fishes caught from a wetland,northeastern Bangladesh

Length–weight relationships (LWRs) and length–length relationships (LLRs) of three ecologically important fishes (Aplocheilus panchax, Danio rerio and Esomus danrica) were reported from a wetland, northeastern Bangladesh (23 58 N, 89 38 E). Samples were collected monthly using traditional fishing gear including fine meshed (2.0 mm) push net and fine meshed (3.0–4.0 mm) surrounding net during January to December 2014. For each individual, total length (TL), fork length (FL) and standard length (SL) was measured to 0.1 cm, while body weight (BW) was measured to 0.01 g accuracy. Allometric coefficient (b) values were 3.10 for A. panchax, 3.38 for D. rerio and 3.52 for E. danrica. In addition, the LLRs were also highly significant with r² ≥ 0.954.     

Species composition and length‐weight relationship of fishes in the Candaba wetland on Luzon Island,Philippines

The length‐weight relationships or LWR (W = aL^b) of 18 of the 21 fish species caught in 2007–2008 from the Candaba wetland in central Luzon, Philippines are reported. These species belong to 14 families and the LWR of six species are first documented in this paper. Cyprinids comprised the greatest number of species. The high significance of the LWR parameters indicate that fish weight may be predicted from length, at least within the range of the fish lengths recorded. This first reference to the LWR of fishes from the Candaba wetland provides baseline data for the conservation management of fish biota in this threatened ecological resource.