Length-weight Relationship Research Articles

Length-Weight Relationship and Condition Factor of Fishes in Two Major Rivers, the Chao Phraya and the Bang Pakong, in Thailand.

Length-weight relationship (LWR) was used as a tool to assess the status of fish stocks, through condition factor, in major rivers in Thailand. Fifty-one fish species from each river, i.e., The examined for LWR using 11 years of monitoring data (2010-2020) for Bang Pakong and 14 years of monitoring data (2007-2020) for Chao Phraya, which comprised 57,871 samples. The parameters for LWR and condition factor were examined by species and by body shape, i.e., ovate, oblong, elongate or eel-like. The coefficient of determination (r 2 ) of all log-transformed LWRs was greater than 0.90. Parameter b of LWR ranged between 2.06 and 3.46 (median = 3.00) for fishes from the Chao Phraya River and between 1.72 and 3.68 (median = 2.76) for fishes from the Bang Pakong River. The overall condition factor, which implies the well-being that indicates the health or fattening of the fishes in a stock, ranged between 0.93 and 1.09. There was no significant difference in the overall well-being (P = 0.279) between the two rivers. Fishes with oblong and elongate shapes in the Chao Phraya River showed higher median values of parameter b of LWR than those from the Bang Pakong River. However, there was no significant difference (P > 0.05) in the well-being of the fish stocks between the two rivers when pooled by shape. The findings are fundamental information for fish stock assessment in the two rivers, which greatly support the small-scale fisheries in Thailand.

Length-weight Relationship and Condition Factors of Seven Penaeus Shrimp Species along the Southeast Coast of Tamil Nadu (Southern India)

Background: The present study of the length-weight relationship and condition factors of seven shrimp species on the southeast coast of Tamil Nadu between July (2022) and February (2023) also estimated the coefficient of determination (r2). Methods: For shrimp species, the length-weight relationship shows some species have significant positive coefficients which have a determination by (r2 greater than 0.5) like Penaeus indicus, Penaeus mergiuensis, Penaeus canaliculatus, Penaeus latisulcatus, Penaeus monodon, some species have shown negative as (r2 greater than 0.5) value like Penaeus japonicas and Penaeus semisulcatus. Result: All shrimp species have heterogeneity evident in intercept (a). The growth exponent (b) varied between 0.278 and 2.289 and it significantly (p=0.05) deviated from the value of less than 3 which denoted negative allometric growth for all Penaeus shrimp species.

Influence of Dietary Protein Content on Growth Performance, Feed Efficiency, Condition Factor, and Length-Weight Relationship in Cyprinus Carpio During the Summer Season

Influence of Dietary Protein Content on Growth Performance, Feed Efficiency, Condition Factor, and Length-Weight Relationship in Cyprinus Carpio During the Summer Season

Length-weight relationship and relative condition factor of yellowfin tuna (Thunnus albacares: Bonnaterre, 1788) West Sabah Waters

Length-weight relationship and relative condition factor of yellowfin tuna (Thunnus albacares: Bonnaterre, 1788) West Sabah Waters

Investigating temporal variability and influence of condition on fecundity and spawning of spotted wolffish (Anarhichas minor) in Icelandic waters

Spotted wolffish (Anarhichas minor) is a poorly understood species which is often captured as part of mixed demersal fisheries across its range. Abundance has declined in many regions and there is a need for greater knowledge on its biology. To improve our understanding of reproduction of A. minor, we investigated inter- and intra- annual differences in fecundity, the influence of condition on fecundity and time scale of ovary development. From 2006 to 2021, 150 females A. minor were sampled in Icelandic waters. Of these females, 73 were also used to estimate spawning time together with an additional 334 females from commercial catch and surveys from 2006 to 2023. Backwards extrapolation of oocyte size indicates that vitellogenesis begins in December and is likely completed after 8–10 months. There was no evidence of either intra- or inter-annual differences in fecundity, indicating that downregulation is minimal and that fecundity of A. minor is stable between years. A positive relationship between oocytes size and fish length was detected, while body condition and hepatosomatic index had only a small influence on fecundity in comparison with weight. There was a negative relationship between length and relative fecundity and the exponent of the fecundity–length relationship was lower than exponent of the weight–length relationship. Therefore, total egg production is likely not proportional to the spawning stock biomass of A. minor, and unusually, total egg production would decrease with increasing proportion of larger fish in the population. The spawning season was estimated to be from middle of August to middle of October with peak of spawning in September.

Population structure and abundance of the amphidromous prawn Macrobrachium tenellum (Smith, 1871) (Decapoda: Caridea: Palaemonidae) in the lower basin of Ameca River, western Mexico, before anthropogenic modifications

Abstract The population of the freshwater prawn Macrobrachium tenellum (Smith, 1871) in four sites in the lower part of the coastal plain of the Ameca River, Mexico is analyzed before drastic anthropogenic modifications of the riverbed occurred. Of the 7,100 individuals of M. tenellum collected between February 2015 and January 2016, 45.7% of which were females (3,250), 4.3% ovigerous females (309), 39.3% males (2,79), and 10.6% undifferentiated (750). Males were significantly larger and heavier than females. In general, the largest individuals were collected at the most distant sites from the coastline (Colomo and San Juan), whereas the smallest ones were captured near the river mouth. The sex ratio (males:females 1:1.3) deviated from the expected 1:1. The length-weight relationship of females, males, and the population in general indicated a negative allometric growth for all three groups. The results of our research may serve as a reference point for future investigations assessing the impact of anthropogenic changes on M. tenellum populations.

Length-Weight and Length-Length Relationships of 39 Demersal Fish Species of an Estuarine-Coastal Ecosystem from the Northwestern of the Baja California Peninsula, Mexico

The length-weight (LW) and length-length (LL) relationships of 39 demersal fish species belonging to 19 families were calculated. Fish samples were collected monthly during the open (September–February) and close (March–August) shrimp fishing seasons from 2014 to 2022 by the artisanal fishery in the Bahía Magdalena-Almejas lagoon system (BMA), using small boats and a shrimp bottom trawl with 16–17 m top rope and 38 mm mesh opening. Total (TL) and standard (SL) lengths and total weight (TW) were measured for all fish specimens. The b parameter of the LW relationship ranged from the minimum of 2.483 for Cynoscion parvipinnis to 3.775 as the maximum for Bagre panamensis while, for the LL relationship, the parameter b ranged from 0.685 for Balistes polylepis to 0.994 for Orthopristis cantharinus. Both LW and LL relationships were highly correlated (r2>0.95; P<0.05. The parameter b of the LW relationship indicated that 59% of the fish species showed isometric and 41% allometric growth. Information on LW and LL relationships is updated for thirteen species, and four are reported for the first time: Citharichthys xanthostigma, Ophidion galeoides, Pleuronichthys guttulatus, and P. ritteri. This study will be useful to update the LW relationship parameters for data-poor fish species and contribute to the accuracy of fish stock assessment in the BMA fisheries.

Demersal Fish Community in the Near-Shelf Zone of the Cosmonaut Sea, Southern Ocean

Studies on the demersal fish composition of the East Antarctic nearshore region are very scarce due to the harsh physical geography of the East Antarctic region, which is covered in ice and snow year round, leading to a scarcity of scientific surveys. Based on the data from the bottom trawl survey conducted by the 37–38th Chinese National Antarctic Research Expedition (CHINARE) program in the Cosmonaut Sea, East Antarctica, the species of demersal fishes were identified, and the demersal fish composition and the characteristics of depth distribution were examined and analyzed. The basic biological information of highly abundant species was analyzed. The results from 97 individuals sampled within 30–60° E, south of −65° S, indicate that the fishes belong to 5 orders, 11 families, 19 genera, and 23 species. Most of the species are found in Myctophidae and Bathydraconidae, and the most common species is Macrourus whitsoni (Macrouridae). Macrourus whitsoni and Prionodraco evansii have a high abundance in the survey. Macrourus whitsoni has body lengths of 144–662 mm and body weights of 17.3–1425.1 g, and Prionodraco evansii has body lengths of 90.18–134.33 mm and body weights of 4.9–20.7 g. The length–weight relationships for Macrourus whitsoni and Prionodraco evansii are y=0.00002x2.748 and y=0.000006x3.353, respectively. All the Macrourus whitsoni samples were found in waters deeper than 1000 m, with the highest number of individuals captured at depths of 1500–2000 m. Prionodraco evansii was found only at stations less than 250 m deep. These results complement the demersal fish composition and distribution data of the Cosmonaut Sea, East Antarctica. These data can provide valuable basic information for characterizing regional assemblages and delineating zoogeographic boundaries.

Length-Weight-Age Relationship of Schizothorax eurystomus Kessler, 1872 and Comparison to Other Snow Trout Species in Central Asia

This study presents a comprehensive analysis of the length-weight relationship, condition factors, and age of Schizothorax eurystomus in the Shakhimardan River basin in Central Asia, along with a comparative perspective to other Schizothorax species in the region. The study found that S. eurystomus exhibits positive allometric growth, which is consistent with similar patterns observed in this species from the Syr Darya River basin. The two analyzed condition factors showed mean values within the normal range, indicating good feeding and environmental conditions. However, significant disparities between minimum and maximum values of these factors indicated varied growth conditions which may be influenced by anthropogenic factors. Age estimation using opercular bones showed variations in the total length among fish of the same age, and a clear age distribution pattern across different sites. Younger fish predominantly inhabited the shallower, warmer, and lower sections of the river, which is impacted by agricultural water diversion, while older specimens were found in areas with higher discharge and deeper pools. Overall, this research provides valuable insights into the life history traits of S. eurystomus, underlining the need for sustainable fishery management and conservation strategies in the Shakhimardan River basin. The findings also emphasize the importance of considering habitat quality and anthropogenic pressures regarding understanding both fish population dynamics and growth patterns.

Length-weight relationships of 15 mesopelagic shrimp species caught during exploratory surveys off the Canary Islands (central eastern Atlantic)

Length-weight relationships (LWRs) were estimated for 15 mesopelagic shrimp species off the Canary Islands (central eastern Atlantic). Total length, cephalothorax length and total weight were taken for individuals collected during three research campaigns using a commercial semi-pelagic trawl net. The most represented families among the collected species were Sergestidae and Oplophoridae, with eight and three species, respectively. Overall, 60% of the species showed isometric growth, 33.3% negative allometry and 6.7% positive allometry. These 15 LWRs are the first contribution on mesopelagic shrimp species from the northwest Africa region, contributing to knowledge on the relative growth of these crustaceans.

Length-Weight Relationship and Condition Factor Channa Marulioides (Bleeker, 1851) In Kapuas River – West Kalimantan as a Conservation Aquatic Resources Effort

Channa marulioides is one of the species that is facing a population decrease due to high fishing activity. This study aims to determine the value of the length-weight relationship and condition factors of C. marulioides in the Kapuas River as a relevant conservation effort. Several sampling areas in this study were used to represent the Kapuas River, including Kapuas Hulu River in Kapuas Hulu Regency, Putussibau District; The central part of the waters area of ​​Sintang Regency in Sintang Regency; and in the downstream waters of Pontianak City. The study carried out the sampling by analyzing the criteria for specimens with a dimension weight > 500 grams and length > 30 cm, with the same amount for each sex. The results showed that the growth type in the upper and middle waters was positive allometric with a value of b 3.1; however, it is negative allometric in the middle and upstream waters with b values ​​of 2.5 and 1.7. After research, the condition factor of the upstream and middle waters was observed to be in good condition with a value of 1. However, in the downstream waters the condition of the fish was rather bad with a value below 1, namely 0.99. The study concludes there is a decrease in the quality of the aquatic environment and the food availability from the middle waters to the downstream. This is what underlines conservation efforts in the form of domestication activities within the scope of structured fish farming.

The Devil Firefish Pterois miles (Bennett, 1828): Life History Traits of a Potential Fishing Resource in Rhodes (Eastern Mediterranean)

The devil firefish Pterois miles (Bennett 1828) is recognized as one of the 100 worst invasive alien species (IAS) in the Mediterranean Sea with significant socioeconomic and ecological implications. A total of 363 individuals were collected between April 2021 and March 2022 from the Levantine Sea (the Eastern Mediterranean), aiming to assess the current progression of the population. The male to female ratio (1:1.03) did not significantly depart from 1:1, with length–weight relationships exhibiting positive allometric growth. Five age groups were identified, with the third and fourth age groups being the predominant (74% of the population). The highest reproductive intensity was observed during summer followed by autumn. The onset of sexual maturity (L50) for the total population was estimated at 22.44 cm in total length (2.1 years). The asymptotic length was estimated at 45.35 cm for the total population, with males growing larger than females. Longevity was estimated at 14.4 years for the total population. The inflection point was estimated at 4.31 years for the total population. Length with a 50% probability of capture (LC50) was estimated at 23.03 cm, with the respective age (t50) of 2.2 years. The exploitation rate (E = 0.48) indicated that the population is underexploited. The optimum (Fopt) and target (Flim) fishing mortality were higher in comparison with the present fishing mortality (F = 0.41), indicating a potential for commercial exploitation of the species.

Length-weight relationship and condition factors of Lepturacanthus savala in Lampung Bay, Indonesia

Abstract. Julian D, Reza M, Putra MGA. 2024. Length-weight relationship and condition factors of Lepturacanthus savala in Lampung Bay, Indonesia. Biodiversitas 25: 510-515. Scarce information exists regarding the growth aspects of ribbon fish (Lepturacanthus savala Cuvier, 1829) in Lampung Bay waters. Thus, this study aimed to analyze the growth characteristics as fundamental information for managing L. savala fishery resources in the waters of Lampung Bay. The method of this quantitative and descriptive study was to analyze the growth of L. savala. Length, weight, and sex ratio data were acquired through a purposive sampling method based on the catch results from gillnet landings at Lempasing Fishing Port, Bandar Lampung. A total of 347 specimens were collected during data collection from May to August 2023, with a length range between 21.6-59.8 cm of total length (TL) and the highest frequency observed in the length interval class of 33-36 cm, consisting of 105 specimens. The results showed that the growth pattern of L. savala is positively allometric, with a value of b equal to 3.0915. The sex ratio between males and females is 1:2.4. The condition factor values ranged from 0.0442 to 2.9281, with the highest average value observed in June for males and females, reaching 1.03.

Morphological Variation and New Description of the Subcutaneous Gland of Sepiella inermis (Van Hasselt, 1835) in Thai Waters

The external morphology and morphological variations of Sepiella inermis vary across regions, necessitating investigation. However, the histological information on the subcutaneous gland has been insufficient to describe it. In this study, specimens were systematically collected and characterized from the Gulf of Thailand. Regarding external morphology, female cuttlebones exhibit greater width and more pronounced curves compared to males, while males feature 17–19 white dots along the fin margins. The presence of the subcutaneous gland was discerned during the embryonic stage at stage 19. A histological study of the subcutaneous gland illustrated the structure and development of the gland in both embryonic and adult stages, with four layers of membranes covering the gland. In the adult stage, trabeculae are dispersed throughout the gland, whereas in the embryonic stage, they form four distinct lines. The morphometric analysis revealed significant differences between males and females (p < 0.05) and the morphological variations within both sexes across the seven study areas exhibit significant differences (p < 0.05). According to the discriminant analysis results, there were significant differences (p < 0.05) between the groups in Surat Thani Province. Examining the length–weight relationship between dorsal mantle length and body weight showed significant differences between the sexes, indicating an allometric growth.

Estimation of Length-Weight and Condition Factor of Indian Major Carps and Selected Indigenous Fish Species in Chandrakeshar Reservoir, Dewas (M.P.), India

This paper investigates the length-weight and condition factor of Indian major carps and selected indigenous fish species in Chandrakeshar Reservoir, located in Dewas, Madhya Pradesh, India during January, 2021 to December, 2023 throughout different seasons. The study aims to contribute valuable insights into the growth patterns and overall health status of these fish populations in the reservoir. A comprehensive survey was conducted to collect length and weight data from various individuals representing major carps, including Catla catla, Labeo rohita, and Cirrhinus mrigala, along with indigenous species prevalent in the region. The length-weight relationships for each species were determined using established methodologies, providing essential parameters for growth assessments. Concurrently, the condition factor (K) of fish well-being and habitat suitability, was calculated to evaluate the overall health and adaptability of the fish in the Chandrakeshar Reservoir. Results provides the basic information regarding fish productivity which may be suitable for better management of Indian major carps and indigenous fishes in Chandrakeshar reservoir.

Length–Weight and Body Condition Relationships of the Exploited Sea Cucumber Pearsonothuria graeffei

Fishery stock assessments are often based on morphometric data from underwater diver surveys and landing surveys. Measurements of body length are usually converted to estimates of body weight, yet length–weight equations might differ among localities. We evaluated morphometric models for the sea cucumber, Pearsonothuria graeffei, collected at Lizard Island on the northern Great Barrier Reef, Australia, and explored differences in relative condition factor (Kn) across animal sizes. The estimation of body weight was compared among relationships with four different body size metrics: observed body length, SLW (square root of the body length–width product), recalculated body length (Le) from SLW, and body basal area. The basal area of the animals, the SLW index and Le provided more reliable estimations for body weight than using body length alone yet accounted for half of the variation in body weight. The length–weight relationship from animals at Lizard Island differed considerably from relationships published for the same species in New Caledonia and Philippines. Body condition was variable, and our model predicted a peak at 35 cm body length. Body metrics such as basal area, SLW index, and Le could offer more precise models for estimating the body weight of sea cucumbers for fishery purposes. Equations for estimating body weight from length and width of the sea cucumbers should be based on locality-specific data because morphometric relationships are spatially variable.

Biological and growth parameters of Plotosus lineatus in the Mediterranean Sea.

This study examined the age distribution and growth characteristics of the striped eel catfish (Plotosus lineatus), which is an invasive alien species in the eastern Mediterranean. A total of 1,011 samples were collected from Iskenderun Bay (Turkey), with lengths ranging from 5.1 to 16.8 cm, predominantly comprising females (1:1.92). Age 3 represented the majority in the population (52.03%). The value of the scaling exponent "b" of the length-weight relationship was less than "3" for both sexes (females: 2.28; males: 2.26; combined: 2.27). The results for the von Bertalanffy growth parameters were observed for the combined sexes as, L∞ = 24.9934 cm, k = 0.1718 year-1, and t₀ = -1.7707 years. The striped eel catfish populations in Iskenderun Bay exhibited negative allometric growth patterns and were predominantly composed of adult individuals. This study presents the dataset on the length-weight correlations, age-growth characteristics, and von Bertalanffy growth parameters of Plotosus lineatus in the Mediterranean Sea, thereby significantly contributing to comprehending the stock dynamics. It is anticipated that this study will make a significant contribution to the management of P. lineatus stocks, given its invasive nature.

The Length-Weight Relationships of Twelve Fish Species from the Heishui River, China

Length-weight relationships are presented for twelve fish species collected at 22 sampling points in the Heishui River, a priority tributary for fish conservation in the mainstream of the Baihetan Reservoir area, China. A combination of gill nets was used for sampling over a period between November 2018 and May 2021. The gill nets consisted of 12 nets per point with dimensions of 20 × 2 m (length and width), mesh size ranging from 20 to 80 mm, and soaking depth ranging from 40 to 160 cm. In addition, fixed gill nets were employed, with 10 nets per point having dimensions of 10 to 30 m in length and 1.5 to 2.5 m in width. The mesh size of these fixed gill nets was 10, 15, or 20 mm. This study presents the length-weight relationships of twelve species for the first time in the Heishui River Basin, including the new maximum body length of Pseudorasbora parva (Temminck and Schlegel, 1846). The slope (b) values for the assessed species ranged from 2.5 to 3.5. All the estimated relationships are highly significant (P<0.05) with a high coefficient of determination R2 ranging from 0.9574 to 0.9997. It is expected that the results obtained from this study will contribute to filling the knowledge gap in this area and also assist fisheries scientists in future assessment studies.

Stock Evaluation of the Euryhaline Cichlid, Etroplus suratensis (Bloch, 1790), from Significant Brackish and Freshwater Regions of India

The present study evaluates stocks of Etroplus suratensis concerning length-weight relationships (LWRs), condition factor (K), and truss analysis from different habitats, viz., West Bengal (freshwater hatchery), Gujarat (brackish water grow-out pond), and Odisha (Chilika lagoon) in India. All the stocks were collected using gill nets with various mesh sizes of 20–50 mm and cast nets with mesh size of 15 mm from February 2021 to September 2021. The total length (L), weight (W), and digital pictures were taken for LWRs and principle component analysis (PCA). The total length (L) and total weight (W) were measured to the nearest 0.1 cm and 0.01 gm, respectively, followed by regression analysis. The values of parameters “b” in the LWRs equation were estimated within the range of 2.50–3.82 and intercept “a” values (0.235–0.779) and “K” (1.07–3.37), respectively, for all different habitats and ecosystems with significant correlation values (R2 ≥ 0.85). In truss morphometric analysis, principal component 1 (PC1) contributed the highest (93.1%) and principal component 2 (PC2) contributed 4.6% to the size and shape variation amongst the stocks from different habitats and ecosystems. The scatter plot analysis and canonical variate analysis (CVA) have shown that the Gujarat and West Bengal stocks are closely placed and separated from the Chilika-Odisha stock. Similar variations were also observed in the ANOSIM boxplot analysis, where Chilika-Odisha stock scored higher than the other two stocks. Since data available regarding LWRs and truss morphometry studies of E. suratensis from different habitats are limited, the present study will provide a clear insight into the differentiation of E. suratensis stocks from different habitats in India. The overall findings of the present study could be utilized for the conservation and sustainable management of E. suratensis.

INTRA-SPECIFIC DIVERSITY OF THE SILVER GRUNT (Pomadasys Hasta) IN THREE LOCATIONS OF BANGLADESH BASED ON MORPHOMETRIC ANALYSIS

Morphometric variation is a useful tool for studying a species' population structure. The present study was performed to assess the intra-specific diversity between three stocks of the Silver grunt Pomadasys hasta (Khulna, Satkhira and Patuakhali of Bangladesh). Length-weight relationship, condition factor and few other morphometrics were analyzed using both univariate and multivariate approaches. A total of 105 samples were subjected to the analysis (weight (95.05 ±44.22 g) and length (16.18±2.57cm). A total of eleven morphometric traits including standard length (SL), head length (HL), pre dorsal length (Pre DL), dorsal length (DL), pre-anal length (Pre AL) , pre-pelvic length (PreVL) , pre pectoral length (PrePL), pre-orbital length (PrOL), body depth (BD), eye diameter (ED) and pre orbital length (PreOL) were measured. Significant differences were found in four morphometric measurements including head length (HL % of total length), eye diameter (ED % of HL), dorsal length (DL %) and pre dorsal length (PreDL%). A negative allometric growth was observed, as the slope b was far below 3. The highest value of b was found in Satkhira (2.7) and the lowest value of b was found in Khulna (2.07). Three separate stocks of P. hasta exhibited morphological variations in their attributes. The divergence among the stocks could have resulted from both environmental and genetic variances. The outcomes of the study will be helpful for management and conservation of natural population of Datina (P. hasta) in Bangladesh.