Length-weight Relationship Research Articles

Seasonal variation in the population structure and production of the copepod Calanus sinicus in the Yellow Sea

Abstract We estimated the total production of Calanus sinicus over four seasons by measuring somatic and egg production rates in the Yellow Sea. In the process of measuring somatic production, the length–weight relationship and growth rates of C. sinicus in this region were also derived. The population abundance and biomass of C. sinicus were especially high in spring. All copepodite stages had similar proportions in spring, whereas the late stages and adults were most common in summer. The mean total production of the C. sinicus population was 107.6–259.7 μg C m−3 day−1, ranging from higher values in spring to lower values in summer. The annual total production of C. sinicus in the Yellow Sea was 64.3 mg C m−3 year−1 (4032 mg C m−2 year−1). The production of C. sinicus was positively correlated with chlorophyll a concentration, rather than water temperature or salinity. This study is the first to quantify the secondary production of C. sinicus in the Yellow Sea. These findings will broaden our understanding of the ecology of C. sinicus and its contribution to the Yellow Sea food web.

Length-Weight Relationship and Condition Factors of Keudawah (Rasbora sp., Family: Danionidae) in the Krueng Lanca Flows of Nagan Raya Regency, Aceh, Indonesia

Keudawah (Rasbora sp.) is a native species found in freshwater, especially Krueng Lanca of Aceh Province, Indonesia. Length-weight relationships (L-WR) and condition factor studies are significant in fisheries, as they offer invaluable insights into fish growth, general welfare, and fitness, especially in freshwater habitats. This study aims to evaluate the fish’s length-weight relationship and condition factor, which can be used to establish monitoring and management systems for this species. Sampling was conducted purposively every month from January to June 2023 at six stations using gill and cast nets. Sampling results were then analyzed in the laboratory. 1118 individual fish (632 males and 486 females) were collected from Krueng Lanca, Aceh Province, with a length frequency of 34-112 mm for males and 46-135 mm for females. The results showed that keudawah had negative allometric growth (both males and females), with b values ranging from 2.307 to 2.962 (for males) and 1.731 to 2.669 (for females). The condition factor (Kn) fluctuated between 0.84 and 0.93 (for males) and 0.82 to 0.94 (for females), indicating less than optimal conditions for this species.

Length–weight relationships and condition factors of five fish species from the coastal region of West Bengal, India

AbstractThe present study presents the length–weight relationships of five brackish water fish species from the coastal region of West Bengal for which this relationship not known to the present time, including Stigmatogobius sadanundio, Brachygobius nunus, Microphis cuncalus, Butis melanostigma and Puntius vittatus. The slope (b) value of the regression ranges between 2.551 and 3.319, with high correlation values (r2 ≥ .943). The relative condition factor (Kn) was also calculated, being >1.0 for all species examined in the present study, indicating of the overall condition of the fish species.

Length–weight relationships of the French pikes Esox spp. (Teleostei, Esocidae)

Length–weight relationships for Pike Esox aquitanicus and Esox lucius from France are provided. A total of 9070 specimens were collected, measured and weighted from 1981 to 2022 throughout France by Departmental Angling Federations and the French Agency of Biodiversity during their survey by electrofishing. For all species, the values of b are 2.960 for E. aquitanicus and 2.987 for Esox lucius. We hypothetize this difference by the poor environment where live the Aquitanian pike with no abundant available food and small prey fish species which do not contribute to good conditions for the growth. The study provides the first reference of length–weight relationships for E. aquitanicus.

Length-weight relationships of farmed major carps (Cattla cattla, Labeo rohita and Cirhinus mrigala) fed with different sources of protein in an intensive polyculture.

The present findings provide information regarding the length-weight relationships (LWRs) of Indian major carps viz Cattla cattla, Labeo rohita and Cirhinus mrigala in an intensive polyculture system. Much work has been done in Pakistan with respect to fish LWRs, much of such work has been ignored. Carps were fed with twelve different formulated diets containing four different sources of protein i.e. fish meal (FM), all parts chicken meal (APCM), corn gluten (CGM) and soybean meal (SBM). Each type of protein is used at inclusion level of 25, 35 and 45% into the formulated diets to evaluate the minimum requirement of that ingredient for optimal growth of in-hand species. The values of slope "b" ranged from 2.20 to 4.90 for these species of carps which showed a strong healthy relationship among variables (level of protein and months).

The Length-Weight Relationship and Condition Factors of Twelve Fish Species, with Special Reference to Cichlid species from the Mediterranean Lagoon, Lake Manzala, Egypt

The Length-Weight Relationship and Condition Factors of Twelve Fish Species, with Special Reference to Cichlid species from the Mediterranean Lagoon, Lake Manzala, Egypt

Length-weight relationship and condition factor for five common fish species in a recently constructed reservoir (Tugwi-Mukosi Dam) - Zimbabwe

Tugwi-Mukosi is a recently constructed reservoir in the Masvingo Province of Zimbabwe. The objective of the study was to estimate the length-weight relationship (LWR) and condition factors (K) of five freshwater fish species collected from the dam. Three hundred eighty-seven fish samples were caught by gill nets and sein between January and September 2021. The estimated exponent value b varied between 2.814 and 3.228 among the fish species. The b values indicated that three species (Oreochromis niloticus, Coptodon rendalli and Micropterus salmoides) followed negative allometric growth (b < 3). In contrast, Clarias garipinus showed isometric growth (b = 3), while Oreochromis mossambicus exhibited positive allometric growth (b > 3). More than 94% (R2 > 0.94) of the weights (responses) variations were explained by the models, so the models fit the data well. The K values of all the fish species, except for C. gariepinus, ranged between 1.3 - 2.2; this indicates that these species are doing well in the reservoir. This observation suggests that Tugwi-Mukosi currently provides a favourable habitat for the fish species. The current study's findings will give valuable baseline data for assessing the status of fish populations and conducting ecological surveys for future fish conservation and management.

Length-weight and length-length relationships of 16 marine fish species in Vietnam

Length-weight and length-length relationships of 16 marine fish species in Vietnam

Length-weight and length-length relationships of 10 fish species from headwater streams of the lower Iguassu River basin, Brazil

Length-weight and length-length relationships of 10 fish species from headwater streams of the lower Iguassu River basin, Brazil

Length–weight relationships for seven fish species caught off Northwest Africa

Abstract Length–weight relationships (LWR) were determined for Deania calceus, Deania profundorum, Merluccius polli, Merluccius senegalensis, Mora moro, Trachyscorpia echinata, and Zenopsis conchifer. Specimens were collected during scientific trawl surveys conducted along the edge of the continental shelf of Morocco and Western Sahara in November–December 2005 and 2006. Fish were measured in relation to total length (TL, to 0.1 cm) and total weight (TW, to 1 g), and sexed when possible. All LWRs obtained for the pooled sexes gave close linear regressions (r2 ≥ 0.93), and LWR parameter b ranged from 2.638 (Z. conchifer) to 3.172 (D. calceus). Data presented herein expand the knowledge base for these species in Northwest Africa, as they have limited or no LWR data publicly available.

The length-weight relationship of Magallana gigas in Krueng Cut, Province of Aceh, Indonesia

This study aims to determine the length-weight relationship of Magallana gigas in Krueng Cut, Banda Aceh City. The research was conducted in October 2020 at Krueng Cut River, Syiah Kuala District, Banda Aceh City. The oyster identification process was carried out at the Laboratory of Marine Biology, Faculty of Marine and Fisheries, Universitas Syiah Kuala. The method used in this study was simple random sampling method. In addition, water quality data were also collected in situ and substrate collected ex situ. The Ostreidae group found in Krueng Cut, Banda Aceh City is the Magallana gigas species. The average oyster found in Krueng Cut, Banda Aceh City is small with length growth ranging from 20 to 50.2 mm. The results showed that the growth pattern of Magallana gigas was classified as negative allometric at three research stations in Krueng Cut River, Banda Aceh, this was based on the value of b < 3. Environmental factors from the three research stations in Krueng Cut, Banda Aceh City are still within the normal limits of Magallana gigas life.

Length-weight relationship for Potamotrygon wallacei (Carvalho, Rosa and Araújo, 2016) caught in the middle Negro River, Barcelos, Brazilian Amazon.

This research aimed to estimate the length-weight ratio (LWR) of the stingray Potamotrygon wallacei, known locally as the cururu, which was caught in streams and lakes in the middle Negro River region, Amazonas, Brazil. The stingrays were captured during the night (from 11 pm to 1 am) near the shores of streams and lakes, through active search using wooden canoes, head lanterns and scoop nets. The samplings were carried out in November 2017 (5 days), February (8 days), March (3 days) and April (2 days) of 2018, totaling 18 days of sampling. The total fresh weight was measured to 0.1 g of accuracy and the disc width to 0.1 cm accuracy. The parameters a and b of the equation W=a.DWb were estimated. This study provides new maximum length data for the cururu stingray.

Length-Weight Relationships of 8 Plateau Indigenous Fishes of Xinjiang, China

Length-Weight Relationships of 8 Plateau Indigenous Fishes of Xinjiang, China

Length-weight relationships of Schistura scaturigina (McClelland, 1838) from Kumaun Himalaya region of Uttarakhand, India

Length-weight relationships of Schistura scaturigina (McClelland, 1838) from Kumaun Himalaya region of Uttarakhand, India

Length-weight relationship of 104 demersal fish species from the continental shelf of the South Brazilian Bight captured in bottom trawl shrimp nets

Length-weight relationship of 104 demersal fish species from the continental shelf of the South Brazilian Bight captured in bottom trawl shrimp nets

Length-Weight Relationship of Fishes in Some Rivers of Morang, Nepal

The length-weight relationship is a crucial aspect of fishery assessments, providing valuable biological information. The length-weight relationship is expressed by the equation W = aLb, where W represents the total weight of the fish and L denotes the standard length. The LWR equation was transformed into a linear form using logarithmic transformation: LogW = a + bLogL. The biometric data obtained from this study includes information on species, sample numbers (N), standard length range, total weight range, and the length-weight relationship constants (a and b) for each species. In this study, we estimated the length-weight relationship of 16 freshwater fish species from some rivers of Morang district, Eastern Nepal. A total of 1,600 fish specimens, representing 16 different species from 5 families were studied from September 2022 to February 2023. The fishes were captured from the river and preserved in 20% formalin for subsequent biometric measurements in the laboratory. Biometric measurements were taken as follows: for each fish, length measurements were listed as standard length or fork length (SL in cm) from mouth to where the caudal fin is lobate. Length measurements were taken with a regular ruler validated against a Vernier Calliper, with an accuracy of 0.1 cm. Weight measurements were obtained using an electronic digital balance with a precision of 0.01 g. While listing weight, a fish consistency was maintained concerning the degree of wetness of the body to ensure accuracy. Among the species listed in the Morang district, Puntius terio has the smallest range of standard length (2.7 cm - 7.4 cm) and total weight (1.07 g - 7.06 g) while Garra gotyla gotyla has the largest range of standard length (4.3 cm - 18.6 cm) and total weight (4.5 g - 15.6 g). These variations indicate the natural size differences among the species. The analysis of the length-weight relationships revealed that all the studied fish species exhibited a negative allometric growth pattern. This means that as the length of the fish increases, its weight increases at a slower rate. The findings of this study contribute to our understanding of the growth patterns of freshwater fish species in the study area.

Length-Weight Relationships and Condition Factors of Kawakawa Euthynnus affinis and Longtail Tuna Thunnus tonggol from Sarawak, Malaysia

Length-weight relationships (LWR) and condition factors (K) were determined for two neritic tuna species Euthynnus affinis and Thunnus tonggol, caught in Sarawak waters. Specimens were collected from five locations around Sarawak between 2016-2019. The r2 value of the LWR for each species re both close to 1 (>0.9),  indicating a highly significant relationship attributed to the length and weight of the fish species . The K values are 1.94 and 1.97, and the values of b in the LW equation are 2.53 and 2.59 for E. affinis and T. tonggol, respectively. The b<3 values indicates negative allometric growth patterns, where the growth rate of body length is faster than the weight gain.  These values fall within the published range of 2.50 to 3.50 for neritic tuna species in the region. The results of this study provide the basic life history parameters and the general condition of the two species, E. affinis and T. tonggol, useful for our tuna fish stock assessment efforts in Sarawak waters.

An ichthyofaunal amendment with the length-weight relations and condition factors of some endemic and invasive freshwater fishes from Western Anatolia

In the scope of this study, fish fauna of Küçük Menderes River and its tributaries, updated with the comparison of the recent ichthyofaunal studies, as well as the length-weight relations (LWR) and condition factors (CF) were estimated for 7 freshwater fish species belonging to six families from the river basin: endemic Oxynoemacheilus eliasi, Cobitis fahireae; invasive, Carassius gibelio, Atherina boyeri, transloce Perca fluviatilis and the native Squalius fellowesii, Cyprinus carpio. The fish samples were collected with various fishnets and DC electro-fishing devices from six stations in 2018 and 2019. The LWR of the fishes was studied based on 379 specimens. The estimated values of parameter b ranged from 2.884 (A. boyeri) to 3.176 (C. fahireae). The coefficient of determination (R2) was changed between 0.792 to 0.980 for all sampling localities. In the study, Fulton’s condition factor ranged between 0.391 (S. fellowesii) to 3.080 (S. fellowesii); the relative condition factor ranged between 0.346 (O. eliasi) to 2.746 (S. fellowesii), respectively. This research is anticipated to contribute valuable insights for the conservation of the species, while also furnishing essential data to inform future fisheries management studies in the region.

Length-weight relationship, reproductive biology and diet of the Javelin grunter Pomadasys kaakan (Cuvier, 1830) (Family: Haemulidae) from western Bay of Bengal

This study provides the first report on the length-weight relationship, reproductive biology and diet of Pomadasys kaakan (Cuvier, 1830) from western Bay of Bengal. Specimens for the study were collected from two locations, Visakhapatnam and Puri, with 301 fishes collected from the former and 153 from the latter. The mean size of P. kaakan at Visakhapatnam was 38.7 cm total length (TL) and 32.07 cm TL at Puri. The length-weight relationship indicated negative allometric growth in the species from both locations. The length at first maturity for female fish was estimated to be 31.5 cm TL at both locations. Our study indicated spawning throughout the year with peaks in February-April and July-August for P. kaakan in the study area. Analysis of diet indicated that in the study region the species had divergent feeding habits. At Visakhapatnam, teleosts (unidentified finfish, eels and silverbellies) were dominant diet items whereas crustaceans (crabs and shrimps) were the dominant diet components of P. kaakan at Puri. The close similarity in size distribution and reproductive biological parameters from the two regions points towards the possibility of a single stock of the species in the study region. Coastal fisheries, Fish stock, Javelin grunter, Life history, Tropical fisheries

Morphological relationships, growth patterns and some aspects of reproductive biology of Sind Danio Devario devario (Hamilton 1822)

This study examined the morphological relationships, growth population factors and reproductive biology of Devario devario collected from the Atrai River of Dinajpur, Bangladesh, for sustainable management and conservation aspects. The length-weight relationships (LWRs) commonly indicated the isometric growth. The Fulton’s condition factor (CFf) and relative body weight (BWr) varied across sexes. A positive correlation was found in length-length relationships (LLRs); among total length (TL), standard length, head length and fork length. The asymptotic lengths were 7.5, 7.2 and 7.5 cm, with growth rates of 0.78‒1.8, 0.6‒3.4 and 1.8‒3.6 year–1 while total mortality was 1.22‒3.06, 0.97‒7.07 and 3.70‒6.09 year–1; fishing mortality was –0.87 to –1.04, –0.97 to 1.09 and –0.05 to –0.23 year–1; natural mortality was 2.26–3.93, 1.94–5.98 and 3.93–6.14 year–1 for female, male and combined sexes respectively. The highest probability of capture (L50) was 5.74‒6.15 cm. The gonado-somatic index ranged from 32.75±1.82 to 44.12±2.73, with a peak in April to May. Fecundity was recorded from 3253±289 to 4831±342, with a significant correlation among TL, BW, gonad length (GL) and gonad weight (GW). These initial findings on D. devario will serve as the basis for future research and management.