Length-weight Relationship Research Articles

Length–weight relationships, condition factor and relative condition factor of blood cockle, Tegillarca granosa (L. 1758) collected from the west coast of Cox’s Bazar, Bangladesh

Blood cockle (Tegillarca granosa) is a commercially important bivalve species harvested from aquaculture and natural stocks. Length–weight relationships, condition factor (K) and relative condition factor (Kn) of T. granosa were investigated collected monthly from the intertidal zone on the west coast of Cox’s Bazar, Bangladesh during July 2018-June 2019. A total of 240 individuals shell length (SL) ranging from 3.6 to 6.9 cm, shell height (SH) varying from 3.5 to 5.8 cm, shell thickness (ST) changing from 3.3 to 5.1 cm and tissue wet weight (TWW) deviating from 5.5 to 20.9 g were analyzed. The regression equation established for SL-TWW, SH-TWW and ST-TWW were SL = 0.16 × SL2.476 (r2 = 0.815), TWW = 0.45 × SH2.262 (r2 = 0.681) and ST = 0.43 × ST2.203 (r2 = 538) respectively. Negative allometric growth pattern was inferred from all three different lengths and TWW relationships (b < 3) established for T. granosa of the habitat. SL-TWW exhibited the strongest correlation over SH-TWW and ST-TWW, hence the K and Kn values were established applying SL-TWW relationships. The K values varied from 6.05 to 7.57 and the Kn values ranged between 0.90 and 1.18. The highest Kn value reported in June (1.18) could be the most suitable time for harvesting healthier animals from the habitat. The negative allometric growth patterns observed for different lengths and TWW relationships indicate that T. granosa on the west coast of Cox’s Bazar does not exhibit uniform growth in all dimensions, and shell lengths increase faster than soft tissue growth. The information could be useful by the managers for conservation and sustainable management of the species.

Unveiling the Health and Growth Patterns of 11 Goatfish Species (Family: Mullidae) along the Coast of Gulf of Mannar: Evidence From Length-Weight Relationship and Relative Condition Factor Analysis

Unveiling the Health and Growth Patterns of 11 Goatfish Species (Family: Mullidae) along the Coast of Gulf of Mannar: Evidence From Length-Weight Relationship and Relative Condition Factor Analysis

Length-Weight Relationships of Eight Salmonid Species from Western Siberia

Length-Weight Relationships of Eight Salmonid Species from Western Siberia

Diversity and biological characterization of anguillid eels in Pangani and Rufiji river systems, Tanzania: Implications for conservation.

Tropical rivers in the western Indian Ocean are under significant human activity pressure, impacting the aquatic fauna, including freshwater eels. However, conservation efforts are hindered by a lack of comprehensive knowledge of these species. This study used a combination of morphological characters and molecular markers (mitochondrial cytochrome oxidase subunit I) to identify anguillid eel species unambiguously. The study revealed the presence of Anguilla bengalensis, Anguilla bicolor and Anguilla marmorata, with the last being a new report for the Pangani River. The study also established length-weight relationships for A. bicolor and A. bengalensis and observed significant differences in gonadal development and physiological indices among maturity levels. No study was performed for A. marmorata due to an insufficient sample size (n = 2). The eye index and pectoral index provided measures of maturity, indicating significant morphological changes during maturation. Understanding the biology and ecology of anguillid eels is crucial for developing effective conservation and management strategies. Due to the vulnerability of these migratory species to various human pressures, concerted efforts are needed to protect their populations and the integrity of freshwater ecosystems in the region. This study provides valuable insights into the diversity and biological characteristics of anguillid eels in East Africa, filling crucial knowledge gaps and providing a foundation for informed conservation actions. The findings of this study have broader implications for regional freshwater conservation, particularly in regions facing similar environmental challenges. They can serve as a reference point for international efforts to protect freshwater biodiversity, in general, and catadromous anguillid species, in particular.

Length-weight relationship and stomach contents of glass perchlet (Chanda nama) in Begnas Lake, Nepal

Elongated glass perchlet is a freshwater fish species in the Asiatic glassfish, family Ambassidae and order Perciformes. Length-weight relationship, condition factor, stomach contents and gastro-somatic index (Ga.SI) of Chanda nama were analyzed between February and April 2024 from the Begnas Lake of Pokhara Valley, Nepal. The total length was recorded in the range of 4.8 cm to 7.5 cm and total weight in the range of 0.81 gm to 5.52 gm. Similarly, the gut length and gut weight were in the range of 0.7 cm to 2 cm and 0.15 gm to 0.91 gm, respectively. Total length and body weight were positively correlated (R = 0.95, p &lt; 0.05) whereas gut length and gut weight were negatively correlated (R = -0.19, p = 0.15). The value of growth exponential (b = 3.02) indicated positive allometric growth. The frequency of each of food items observed in stomach contents were scales (91.7%), insects (33.3%), zoobenthos (50%), eggs (41.7%), algae (25%), nostoc (36.7%) and unidentified materials (20%) throughout the study period. In conclusion, C. nama was lepidophagy. The Ga.SI value was used to determine feeding intensity and was found to be highest in the month of March and lowest in April. The present study suggested for further study about the C. nama and other fishes of the lake to know their status.

Comparison of length-weight relationships of three economically important shrimp species in Iskenderun Bay, Northeastern Mediterranean

This study investigates the length-weight relationships (LWR) of three economically important shrimp species (Farfantepenaeus aztecus, Penaeus semisulcatus, and Metapenaeus monoceros) in İskenderun Bay, Northeastern Mediterranean, using data collected between October 2023 and November 2024. A total of 579 specimens were analyzed, with F. aztecus contributing the highest sample size (238 individuals), followed by P. semisulcatus (214) and M. monoceros (127). Carapace length (CL) and weight (W) measurements revealed interspecies differences. The average carapace length was 5.66 mm for F. aztecus, 6.63 mm for P. semisulcatus, and 5.08 mm for M. monoceros. Average weights were 32.81 g, 39.68 g, and 31.48 g, respectively. Growth patterns, determined by the parameter 𝑏, showed distinct gender differences. Females generally exhibited negative allometric growth, while males displayed either isometric or positive allometric growth, depending on the species. Statistically significant differences in growth types were observed, particularly in M. monoceros males (p &lt; 0.05). These results provide crucial insights into the population dynamics and ecological adaptations of shrimp in İskenderun Bay. The findings contribute to understanding the species’ growth characteristics, supporting the development of sustainable fisheries management strategies in the region.

Fishery, Growth and Reproductive Biology of Metapenaeus affinis (Decapoda, Penaeidae) in the Iraqi waters

The study evaluated the fishery, growth and reproductive biology of the Jinga shrimp (Metapenaeus affinis) in Iraqi waters from November 2022 to October 2023. The monthly shrimp landings from Iraqi marine waters ranged from 57 tons in December 2022 to 407 tons in September 2023, with an annual value of 3,515 tons. 8,021 individuals of M. affinis, ranging from 2.0 to 15.6 cm, were collected from the East Hammar marsh and Iraqi marine waters. The length-weight relationship indicated that males and females exhibited negative allometric growth patterns, with a significant difference between them. The mean values of the relative condition factor were 0.98±0.037 and 1.02±0.043 for males and females, respectively, referring to the healthy condition for both sexes. The growth model for the species was Lt= 16.3 (1- exp (-0.92 (t+0.084))). The overall sex ratio (male: female) was 1:1.41. The length at first maturity (Lm50) was 8.2 cm. The gonadosomatic index (GSI) values fluctuated from 2.14% in June to 4.34% in April for females of M. affinis. These results can assist in fisheries management and conservation of the shrimp species in Iraqi waters.

Non-annual Nothobranchiid (Cyprinodontiformes) Growth Type and Health in Southern Cameroon Rainforest Streams: Perspectives from Condition Indices

Understanding population dynamics involves key variables like growth type and body condition, the latter indicating energy acquisition, foraging behaviour, and prey availability, factors influencing species growth, reproduction, fitness, and survival in their habitat. Therefore, using accurate fish condition indices is essential. This study examined the length-weight relationships of 1010 cyprinodontiform individuals from 12 species of non-annual nothobranchiids in southern Cameroon rainforest streams and their well-being using Fulton (&amp;lt;i&amp;gt;Kc&amp;lt;/i&amp;gt;), allometric (&amp;lt;i&amp;gt;Ka&amp;lt;/i&amp;gt;), and relative weight (&amp;lt;i&amp;gt;Kn&amp;lt;/i&amp;gt;) condition factors. Species differed significantly in length (&amp;lt;I&amp;gt;F &amp;lt;/I&amp;gt;= 56.79, df = 11, &amp;lt;i&amp;gt;p&amp;lt;/i&amp;gt; &amp;lt; 0.00) and weight (&amp;lt;I&amp;gt;F&amp;lt;/I&amp;gt; = 46.66, df = 11, &amp;lt;i&amp;gt;p&amp;lt;/i&amp;gt; &amp;lt; 0.00). Findings showed allometric growth patterns (&amp;lt;i&amp;gt;p&amp;lt;/i&amp;gt; &amp;lt; 0.001 and &amp;lt;I&amp;gt;R² &amp;lt;/I&amp;gt;ranging from 0.808 to 0.965); three species exhibited positive allometric growth (&amp;lt;i&amp;gt;b&amp;lt;/i&amp;gt; &amp;gt; 3) and tended to be thicker, while the other species had negative allometric growth (&amp;lt;i&amp;gt;b&amp;lt;/i&amp;gt; &amp;lt; 3) and tended to be thinner. Nothobranchiid growth pattern does not follow the cube law, with mean &amp;lt;i&amp;gt;Kc&amp;lt;/i&amp;gt; values consistently below 1.0, a range proposed to be that of this fish family and not necessarily indicating a poor fish condition. Mean &amp;lt;i&amp;gt;Ka&amp;lt;/i&amp;gt; values indicated varying feeding intensities among species, ranging from 0.29 ± 0.01 to 7.63 ± 0.21, and influenced by &amp;lt;i&amp;gt;b&amp;lt;/i&amp;gt;-values. Mean &amp;lt;i&amp;gt;Kn&amp;lt;/i&amp;gt; values were always greater than 1.0 across all nothobranchiids, not differing among them and reflecting good growth conditions. The study provides first insights into the growth patterns and health of the nothobranchiids within their unique ecosystem, highlighting the advantage of using multiple condition factors to describe species&amp;apos; physiological and ecological well-being and offering essential perspectives for sustainable management and biodiversity conservation efforts.

Biological and genetic structure of Epinephelus costae (Steindachner, 1878) population in Iskenderun Bay, eastern Mediterranean Sea.

This study aimed to status of the Iskenderun population of Epinephelus costae, an important fish species in the Mediterranean Sea ecosystem, by providing detailed data on its genetic structure using mtDNA COI gene region and biological parameters as length-weight relationship, age-growth characteristics, von Bertalanffy growth parameters. A total of 325 specimens were studied from Iskenderun Bay in the eastern Mediterranean (Türkiye), ranging in length from 16.7 to 43.5 cm. For genetic studies using the mtDNA COI gene region, 30 samples were selected from different size groups representing the population. Age 2 represented the majority of the population (31.69%). The value of "b" of the length-weight relationship was higher than "3" (3.0839). The results for the von Bertalanffy growth parameters were observed as L α =125.8 cm; k=0.0570 year -1; t 0=-2.2410 year. Fulton's condition factor was observed as 1.4120. The growth performance index was calculated as 4.35. The genetic diversity of the population was found to be 0.0332±0.0028. Sixteen haplotypes were observed in the population and haplotype diversity was calculated as 0.9379. Tajima's neutrality test (-0.9437), Fu's Fs Statistic (-0.0340), Strobeck's S Statistic (0.6620), Achaz's Y test (-1.8728), Fu and Li D (1.1570) and F Test (0.4444) were applied to test whether the population is in balance. In conclusion, the biological and genetic analyses carried out within the scope of our study revealed that the Iskenderun population of E. costae is in stable condition.

Population ecology of &lt;i&gt;Parauchenoglanis fasciatus&lt;/i&gt; (gras, 1960) (siluriformes: claroteidae) in a Nigerian rainforest stream

The biology and ecology of Parauchenoglanis fasciatus were investigated in Ikpa River, a blackwater stream in the eastern Niger Delta, Nigeria. The species exhibited a limnophilic and benthopelagic nature, predominantly occupying vegetated marginal areas, ponds, pools, and swamps with muddy bottom deposits. Monthly variations in catch numbers indicated alternating periods of population increase (February, April, July–August, and October–December) and decrease (January, March, May–June, and September). The length–weight relationship showed negative allometric growth (b = 2.793), with monthly variations ranging from 2.451 to 3.835. These variations were significantly correlated with hydrological parameters, including temperature, water level, discharge, transparency, dissolved oxygen, pH, and conductivity. Physiological analysis suggested a balance between anabolism and catabolism in the species. The Von Bertalanffy growth parameters estimated an asymptotic length (L∞) of 17.9 cm total length (TL) and a growth coefficient (K) of 0.265 yr⁻¹. Growth followed a biphasic pattern, with a rapid phase from August to December (0.72 mm month⁻¹) and a slower phase from January to July (0.23 mm month⁻¹). The growth performance index (ø`) was 1.95, while the growth strength index (K*) was 1.81, indicating an overallslow growth rate. The estimated maximum longevity (Tmax) was 11.3 years. Mortality estimates included total mortality (Z= 0.94 yr⁻¹), natural mortality (M = 0.31 yr⁻¹), and fishing mortality (F = 0.63 yr⁻¹). The exploitation coefficient (E = 0.67) suggested that the species is overexploited.

Length-weight relationships of 17 demersal fish species in the Canary Islands (Spain, CE Atlantic).

Ten scientific surveys were carried out at ‘Isla de La Palma’ and ‘La Graciosa e Islotes al Norte de Lanzarote’ Marine Protected Areas (MPAs) between 2003 and 2010. Length-Weight Relationships (LWR) were estimated for 17 fish species using individual fish records collected by fish pots (half an inch mesh size), bottom horizontal longlines (hook size 3/0) and set gillnets (80 mm mesh size). Fish was measured fresh for the total length (to the lower 0.1 or 0.5 cm, depending on the scientific surveys design) and weighted for the total weight (TW, to the 0.1 g). Except for the Myliobatiformes species (with b-values lower than 2.0), the b-value varied between 2.63 and 3.72. All LWRs were obtained from well adjusted linear regressions with R² ≥0.74. In addition, two new maximum lengths were recorded. Data presented herein expand the knowledge base for these species in the Archipelago, where any status assessment of the species affected by the operating fisheries has been possible so far, and remain as datapoor stocks.

Paschim Medinipur (Batı Bengal, Hindistan)’da Puntius chola (Hamilton, 1822)’nın mevsimsel değişime bağlı olarak boy-ağırlık ilişkisi ve kondisyon faktörleri

This study aims to examine the relationship between Puntius chola (Hamilton, 1822) length, weight, condition factor, and relative condition factor, with an emphasis on seasonal variation. The result shows that the species did not strictly follow the anticipated cube law and had negative allometric growth trends in all seasons. The relative condition factor for P. chola ranged from 0.93 to 1.64, the length-weight relationship value “b” varied from 2.57 to 2.91, and the condition factor varied from 0.70 to 2.58. While the condition factor (K) peaked during the winter, the average values of "b" peaked during the monsoon season. The Post Hoc test indicates that the seasonal relationship between length, weight, condition factor, and relative condition factor is significant (P&lt;0.05). The present study will assist fishery managers in creating sustainable management plans for P. chola in its natural habitats.

The growth performance in different seasons of Homatula variegata (Dabry de Thiersant, 1874) in Northern Guizhou, China.

To provide knowledge on growth performance and data that are helpful for resource assessment of Homatula variegata (Dabry de Thiersant, 1874) living in northern Guizhou, China, the current study focused on the length-weight relationship (LWR), the growth pattern, the condition factor (CF), as well as the relationship between muscle metabolomics and growth in H. variegata. A total of 135 H. variegata were collected during 19 months using our patented hookless fishing tackles. The lengths (from the snout tip to the base of the caudal fin) and weights were measured, and the LWR and CF was calculated. Furthermore, the muscle tissues from fin tissues of 8 fish in winter were used for the analyses of metabolomics. The lengths and weights of 135 individuals varied by seasons, and there were opposite changes of the parameter a and the parameter b among different seasons. The parameters of LWR indicated that the growth pattern of H. variegata was the negative allometric growth. Furthermore, the CF of H. variegata was consistent with the seasonal variations of the lengths. Our results displayed that H. variegata exhibited better growth during spring and winter in northern Guizhou. Moreover, the positive correlation between triglycerides (TG) metabolites and CF found in the metabolomics analysis of muscle tissue in winter revealed the potential importance of lipid-rich food for the well-being and growth performance of H. variegata. Taken together, our findings provided basic information on the growth patterns and the relationship between metabolic characteristics and CF of H. variegata.

Species Composition and Length-Weight Frequency Distribution of Lobsters (Panulirus spp.) Landed on The Puger Coast, Jember Regency, East Java

Lobsters are one of the most economically valuable fishery resources, with the majority of catches obtained from marine environments. This study aims to identify and determine the species composition of lobsters based on the fishing gear used by local fishers in Puger Beach, as well as to analyze key biological parameters of lobsters, including the distribution of carapace length and body weight, the length-weight relationship, and sex ratio. Sampling was conducted on lobsters landed at Puger Beach from January to March 2020, resulting in a total of 2,485 individual records containing carapace length, weight, and sex data. Analytical methods included linear regression, class interval analysis, and chi-square tests. Species identification was conducted using the reference by Carpenter and Niem (1998, Volume 2), which confirmed the presence of five Panulirus species landed in the area: P. homarus, P. penicillatus, P. versicolor, P. longipes, and P. ornatus. The composition analysis revealed that the sand lobster (P. homarus) was the most dominant species, with a total of 1,648 individuals. Growth pattern analysis showed a negative allometric relationship, with b-values of 2.8957 (gillnet catches) and 2.8142 (diving with compressor catches). According to Ministerial Regulation No. 56/2016, 41.2% of lobsters were below the minimum legal size based on carapace length, and 27.3% were underweight. The sex ratio of lobsters was balanced at 1:1. However, during the study, 115 egg-bearing female lobsters were still found, indicating non-compliance with Ministerial Regulations No. 1/2015 and No. 56/2016, which prohibit the capture of undersized lobsters and egg-bearing females.

Studies on the length weight relationship of Labeo rohita Fish from Rohri canal near Daleel Dero Sakrand Sindh Pakistan

Studies on the length weight relationship of Labeo rohita Fish from Rohri canal near Daleel Dero Sakrand Sindh Pakistan

Length-Weight Relationship, Morphometric Characters and Meristic Counts of an Endangered Kashmir loach, Triplophysa kashmirensis (Hora, 1922) in Kashmir Himalaya, India

The present study was conducted on the morphometry, meristic characters and length-weight relationship of Triplophysa kashmiriensis (Hora (1922) and was carried out from September 2018 to February 2019. A total of 180 samples were collected from Dagwan and Lidder streams. Various morphometric characters showed a high degree of correlation (R2) between them and the values of correlation ranged from 0.69 to 0.99. The coefficient of variation for various morphometric characteristics was found to be 20.95 % between snout length and total length, and 17.65 % between eye diameter length and total length. The fin formula of the fish was found as D(I)8; A(I)5; P1(10-11); V(7-8); C(17-18). The length-weight relationship was recorded separately for both males and females. The equations found were Log W = -5.485 + 3.167 Log L for males and Log W = -5.440 + 3.153 Log L for females and the combined equation was obtained as W = -5.491 + 3.174 Log L. The value of ‘b’ obtained for the pooled data was found to be 3.174 which is significantly greater than 3 indicating a positive allometric growth in the fish.

Comparing efficiency of literature-based estimation of general biomass using Length-Weight Relationships (LWRs) between freshwater and seawater fishes

Fish biomass estimation is crucial for understanding aquatic ecosystem dynamics and managing fisheries resources effectively. This study evaluated the applicability of estimating fish biomass in Korean aquatic ecosystems using literature-derived General Total Length (GTL) and length–weight relationships (LWRs). We compared the estimated biomasses with measured field biomasses from literatures for freshwater and seawater fish species. Data on individual biomass, habitat, and length-weight coefficients were collected from the literature and databases for 245 fish species. Biomass was estimated using the GTL and representative LWR coefficients and then they were compared to the measured field biomasses from literature. The results showed that this estimation method was applicable only to freshwater species (R² = 0.7133), whereas the estimates for seawater species showed a poor correlation (negative R² values). The removal of outliers (Q > 6) improved the estimation accuracy for the freshwater species. This study demonstrates that literature-based biomass estimation using GTL and LWRs is appropriate for freshwater fish in Korea, but not for seawater species. These findings contribute to the generation of fundamental biomass data for ecosystem modeling and highlight the need for habitat-specific approaches for biomass estimation. Since habitat specific biomass data is deficient, future research should explore biomass estimation through species extrapolation to address data gaps in aquatic ecological studies.

Population Dynamics of Hydrocynus forskahlii (Cuvier, 1819) from Roseires Dam Reservoir, Sudan

This study examines the growth, mortality, and recruitment patterns of H. forskahlii in Sudan's Roseires Dam Reservoir. During the study period, 675 fish specimens were collected from November 2021 to November 2022. The collected samples ranged in total length from 14.3 cm to 57.0 cm, with an average length of 30.599 ± 10.167 cm. Growth parameters, derived from the von Bertalanffy equation, yielded an asymptotic length of 58.8 cm and a growth coefficient of 0.260 yr.⁻¹. Mortality analysis showed a total mortality rate of 0.69 yr.⁻¹, natural mortality: 0.58 yr.⁻¹ and fishing mortality: 0.11 yr.⁻¹. Two recruitment peaks were identified in March/May and July/October. The exploitation rate was 0.17 yr.⁻¹, indicating under-exploitation at sustainable fishing pressure. The length-weight relationship revealed a negative allometric growth. Measures for improved fishery practices based on the study's findings are recommended.

Biological aspects of Rochia nilotica in Run Islands, Eastern Indonesia

Abstract Lola snail (Rochia nilotica) is an important marine resource economically and ecologically. Economically, meat of lola snail is traded for local consumption and the shells are exported as raw materials for making buttons, jewelry and nail paint. Ecologically, it controls the population of macro-algae attached to coral, thus it has a role for the health of coral reef. This research was conducted from July to August 2020 in Run Island, Maluku Province, Eastern Indonesia with the objectives to study biological aspects of lola snail which consist of size distribution, age group (cohort), length weight relationship and condition factor. Samples of lola snail were collected by using linear transect. Shell width of samples collected was measured and weighted. Totally, 80 individuals of lola snail were collected during the study. The results showed that shell width ranging from 10.4 to 120.5 mm (61.63 ± 35.07 mm) while weight ranging between 7.0 and 437.2 g (163.54 ± 183.81 g) and consist of six age groups (cohort). Regression analysis of shell width and weight showed that the value of b = 2.083 with the value of condition factor was 1.0. It can be concluded that population of lola snail (R. nilotica) in the area has six cohorts which consist of juvenile and adult individuals. In addition, the width shell of lola snails population grows faster than weight and has good condition to survive, grow and reproduce.

Key Biological Information on Atlantic Bonito From Small‐Scale Fishery in the Senegal Exclusive Economic Zone

ABSTRACTBiological parameters are critical for the sustainable management of fisheries globally, providing critical insights into population dynamics, ecological interactions, and fish stock resilience. In the Senegalese Exclusive Economic Zone (SEEZ), valuable biological information required for Atlantic bonito stock assessment and implementing effective management measures is either limited or nonexistent. This study aims to address this gap by examining some important biological parameters of Atlantic bonito, one of the most targeted species of small tuna by small‐scale fisheries in the Senegal fishing area. The results reveal important biological aspects, such as the length–weight relationship coefficient (a) of 0.0062 and the rate of weight change with length (b) of 3.2346, which is significantly greater than 3.0. These findings suggest that most fish species exhibit moderately positive allometric growth and an increase in relative body size or weight. The Fulton's condition factor (K) of the combined data ranged 1.18–1.48 (1.34 ± 0.14), suggesting that the fish are well‐nourished in relation to their size. Furthermore, the age of Atlantic bonito in Senegalese waters is approximately 4.6–5 years. The final main growth parameters obtained were Linf = 73.01 cm fork length, with estimated sizes at first maturity (Lm50) for males and females being 42.09 and 38.56 cm, respectively, and 40.75 cm for combined sexes. The results provide important biological aspects for assessing the Atlantic bonito stock, establishing robust harvest control rules (HCRs) for fisheries management, and supporting sustainable fishing for this small tuna for the benefit of coastal communities in the Northeastern Atlantic Ocean.