A Bayesian approach for estimating length‐weight relationships in fishes

A Bayesian hierarchical approach is presented for the estimation of length‐weight relationships (LWR) in fishes. In particular, estimates are provided for the LWR parameters a and b in general as well as by body shape. These priors and existing LWR studies were used to derive species‐specific LWR parameters. In the case of data‐poor species, the analysis includes LWR studies of closely related species with the same body shape. This approach yielded LWR parameter estimates with measures of uncertainty for practically all known 32 000 species of fishes. Provided is a large LWR data set extracted from www.fishbase.org , the source code of the respective analyses, and ready‐to‐use tools for practitioners. This is presented as an example of a self‐learning online database where the addition of new studies improves the species‐specific parameter estimates, and where these parameter estimates inform the analysis of new data.     

The relationship between leaf water repellency and leaf traits in three distinct biogeographical regions

Leaf water repellency (LWR) is the degree to which water droplets repel from a leaf surface. LWR has been suggested as an adaptation to maximize gas exchange during photosynthesis and as a mechanism to increase hydrological inputs beneath the canopy. This article examined the relationships between LWR and leaf traits in 33 species across three distinct biogeographical regions (tropical montane cloud forests in Guatemala; tropical dry forests in Guatemala; and foothills-grassland vegetation in the U.S.). The objectives of this study were to determine if leaf area, leaf thickness, leaf biomass, specific leaf area, leaf toughness, stomatal density, and the presence of epiphylls explained variation in LWR in the 33 species. LWR was greatest in the dry foothills-grassland ecotone in Colorado and lowest in humid cloud forest of the Sierra de las Minas. Most possible pairs of species were significantly different from each other at each study area. Significant variation in all leaf traits was found among species and sites. LWR was not explained by leaf area, leaf thickness, leaf biomass, and specific leaf area. The presence of epiphylls influenced LWR on the abaxial leaf surfaces of species of the Sierra de las Minas. The article concludes that leaf traits related to size and mass do not influence LWR; however, the variation in LWR in species between distinct biogeographical regions remains an important research area in ecohydrology.     

伊朗一沼泽中水生甲虫体长与体重的关系(英文)

本研究所用标本为7种水生甲虫,均采自伊朗Choghakhor沼泽。通过对水生甲虫的体长和体重的测量,研究其体长-体重关系(LWR)。结果表明: LWR参数b的变动范围在2.315~3.117之间。所有被观察的水生甲虫体长与体重关系明显,相关系数(r²)均高。本研究所得到的这种相互关系可被用于确定甲虫体重,并有助于解决其他的一些生态学问题。本研究所提出的体长-体重关系(LWR)限制于所观察到的标本体长范围。     

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

Length‐weight relationships (LWR) for three cyprinid fish species collected from the headwaters of the Nujiang River in Tibet, China, were determined. The values of parameter b in the LWR equations were estimated as 2.54 for Schizopygopsis thermalis, 3.3 for Ptychobarbus kaznakovi, and 2.74 for Schizothorax nukiangensis, respectively. These are the first LWR records for the three species.     

Length–weight relationships for seven fish species of the Napo River,Upper Amazon,Peru

Length–weight relationships (LWR) were estimated for seven fish species from the Napo River and its main tributaries, Arabela and Curaray rivers, Amazon basin, Peru. A total of 652 specimens were sampled between 2012 and 2014 using seines and gillnets. This study reports new maximum total length for four species and new LWR and maximum total weight records for three and five species, respectively.     

Length–weight and length–length relationships and length at first maturity for freshwater fish species of the Salto Santiago Reservoir,Iguaçu River Basin,Brazil

Length‐weight (LWR) and length‐length (LLR) relationships were estimated for 20 species and lengths at first maturity (L₅₀) for six species of freshwater fishes caught in the Salto Santiago Reservoir, Iguaçu River Basin, Brazil. In nine species significant differences were found in the LWR between sexes. Average b‐value for species with no differences between sexes in LWR was 3.12 (SE = ±0.05). Average b‐value in LLR was 0.823. First references on LWRs and L₅₀ are presented for 13 and four fish species, respectively, as well as the new maximum total lengths for eight species.     

Length–weight relationships for Brazilian estuarine fishes along a latitudinal gradient

Ninety-nine length–weight relationships (LWR) were estimated for 70 bentho-demersal fish species captured in four Brazilian estuaries between latitudes 0°S and 25°S. LWR are published for the first time for 13 species. The allometry coefficient ( b ) of the LWR ( W = aTL ^b ) showed a median of 3.147. Positive allometry was dominant (64 of the 99 species x estuary cases), followed by isometry (28) and negative allometry (7). Twenty-two species were caught in two or more estuaries. In most cases (29 of 33 comparisons), the values of both regression parameters differed significantly among estuaries.     

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.     

Improving data deficiencies in length-weight relationships for fish species around an artificial breakwater and adjacent soft-bottom at the central coast of Peru

Long-term environmental monitoring studies includes morphometric data (length and weight) of aggregating fish species around this artificial structure and adjacent soft-bottom habitats. We used these data, obtained biannually (summer and spring) between 2012 and 2018, to estimate population parameters such as length-weight relationships (LWRs) for 28 species. Gender and ontogeny-based differences in LWR were determined in four species, while novel LWR information was generated for all other species.     

Length‐weight relationships for 19 fish species from the Jacuí Delta,RS, Brazil

This study presents length‐weight relationships (LWR) for 19 species captured in the Jacuí Delta in southern Brazil. Most of the species had no previous LWR estimates.     

Length‐weight relationship of freshwater fish,Puntius shalynius Yazdani and Talukdar (Cypriniformes: Cyprinidae), in Meghalaya,India

The present investigation gives the length‐weight relationship (LWR) of Puntius shalynius in Meghalaya, India. The samples for the study were collected from Umiam river. The value of the exponent ‘b’ in the LWR was less than 3, with 0.885 for males and 1.616 in females. This shows that the species exhibit allometric growth pattern. There was no difference in LWR between sexes and seasons.     

Length‐weight and length‐length relationships of three tidepool fish species in the Amazon Coastal Zone of Brazil

Length‐weight relationships (LWR) and length‐length relationships (LLR) were analyzed for three species inhabiting tidepools in the Amazon Coastal Zone, two of them non‐native. Tidepools were sampled in five beaches along the Amazon Coastal Zone in 2011, and samplings were carried out using hand nets. The coefficients of allometry and proportionality were within the ranges estimated for fishes. All three species exhibited coefficients of allometry (b) higher than 3 in the LWR.     

Length‐weight relationships for 22 neotropical freshwater fishes from a subtropical river basin

This paper presents length‐weight relationships (LWR) for 22 species from the Pitangui River Basin, Brazil. For six of these species these are the first LWR records; for nine other species these are the first LWRs recorded in FishBase.     

Length–weight relationships for 11 species at three small hydropower plants on the Sapucaí‐Mirim River (Grande River basin,Brazil)

This paper presents length–weight relationships (LWR) for 11 freshwater fish species from the Sapucaí‐Mirim River, a tributary of the Grande River basin, São Paulo, Brazil. The specimens were captured in quarterly samplings between March 2011 and December 2014, using gillnets of mesh size: 1.5–9.0 cm between knots. The present study adds new information for the maximum length of seven species, and presents new LWR records for four species.     

Length‐weight relationships of 26 fish species from the streams of the upper section of the Paraguay River basin (Mato Grosso,Brazil)

This study provides data on the length‐weight relationships (LWR) for 26 tropical fish species collected in August 2010 (dry season) and May 2011 (wet season), and represents the first LWR references for these species in the small tributary streams flowing into the major rivers of the Pantanal Matogrossense, Brazil.     

Length–weight relationships for selected fish species of Rio Trombetas Biological Reserve: a reference study for the Amazonian basin

Length–weight relationships (LWR) are presented for 27 freshwater fish species representing 11 families captured in the Trombetas River, a clearwater left margin tributary of the Amazon River. The allometry coefficient (b) of the LWR (W = aTL^b) ranged from 2.51 to 3.49, with a median value of 3.00. This study represents the first reference on LWR for 23 species and new records of maximum lengths for 15 species.     

Length–weight relationships for seven fish species from Marajó Bay,Amazon estuary,northern Brazil

Length–weight relationships (LWR) were estimated for seven fish species inhabiting the intertidal mudflats in the Marajó Bay, northern Brazil. A total of 514 specimens were collected quarterly between November 1994 and December 1995 using a beach seine (5 mm mesh size between opposite knots). Slope b of the LWR varied between 2.93 and 3.11, with a mean of 3.02. This study represents the first reference on LWRs for seven species and a new maximum length record for one of these species.     

Length–weight relationships of 20 fish species from Bahía de Matanchen,in the southeast Gulf of California,Mexico

Length–weight relationship (LWR) parameters were determined for 20 fish species belonging to 14 genera and seven families. The fishes were collected monthly (May 2013 to February 2014) by soft‐bottom trawls in Bahía de Matanchén, southeast of the Gulf of California. Sizes ranged between 5.5 and 36.0 cm total length (TL) and weighed between 1 and 901 g. The allometric coefficient (b) of the LWR varied from 2.638 for Chloroscombrus orqueta to 3.668 for Neopisthopterus tropicus. This is the first report of LWR estimations for 15 of the species.     

Length–weight and length–length relationships of 16 fish species from Amapá, Brazilian Amazon

The present study provides length‐weight (LWR) and total length‐standard length (LLR) relationships for 16 freshwater fish species collected in coastal rivers of the northern Brazilian, state of Amapá in 2015. Fishes were caught in heterogenic environments like ponds, stream and river channel with sieve and trawl. As result, we present novel information of LWR and LLR for 11 and 15 species, respectively. Maximum values (first values or new maximum values) of TL, SL and WT are presented for 14, 12 and 15 species, respectively.     

Length–weight relationships of 20 fish species from Pahang River,Maran district,Pahang, Malaysia

This study reports the length–weight relationships (LWR) of 20 fish species from the Pahang River, Maran district, Pahang, Malaysia. The river supplies fishes mainly for local consumption and is a principal body of water for freshwater aquaculture in Malaysia. A total of 12 LWR of fishes were unknown to FishBase, and five new maximum lengths of fishes were identified from the study.