Length-weight Relationship Research Articles

Determination of heavy metal concentration in African pike (Hepsetus odoe) from Alape River, Southwestern Nigeria

Aquatic ecosystems in Nigeria face significant environmental challenges because of anthropogenic activities, resulting in heavy metal contamination. Fish body weight and length and heavy metal concentrations in African pike (Hepsetus odoe) from Alape River, Igbokoda, Ilaje Local Government Area of Ondo State, Southwestern Nigeria, were investigated. Copper (Cu), Cadmium (Cd), Iron (Fe), Manganese (Mn), Nickel (Ni), and Lead (Pb) concentrations were measured in the gills, intestines, and trunks of the fish over six months (i.e., from May 2022 to October 2022) using an atomic absorption spectrophotometer (Buck Scientific’s 210VGP). Significant variations in heavy metal concentrations were observed across different months and organs. The order of concentrations for the six months, from highest to lowest, was Fe (2.26 mg/kg) > Ni (0.37 mg/kg) > Cu (0.23 mg/kg) > Mn (0.27 mg/kg) > Pb (0.05 mg/kg) > Cd (0.01 mg/kg). Higher concentrations were generally observed in the gills and intestines in May and June, whereas elevated levels were observed in the gills in September and October. These concentrations were compared with the maximum permissible limits established by the Food and Agriculture Organization and the World Health Organization for fish consumption, and all measured heavy metal concentrations were determined to be below the permissible limits. Body weight ranged from 172 to 362 g, and length ranged from 15.7 cm to 23.5 cm. The regression coefficient (b) ranged from − 0.134 to 0.204, indicating a relatively weak length–weight relationship. The condition factor (K) exhibited variations in the overall health and well-being of the fish. Based on these findings, the consumption of African pike from the Alape River is currently considered safe for humans, regardless of fish size, with all of the heavy metal concentrations within the permissible limits. However, continuous monitoring is crucial to ensure the ongoing safety of aquatic ecosystems and human health.

Population characteristic of torpedo scad (Megalaspis cordyla Linnaeus, 1758) in the Lampung Bay: Size structure, growth type, and condition factor

Megalaspis cordyla, locally known as ikan bekre, stands as a crucial economic species commonly consumed by the people of Lampung. The escalating demand for this fish has significant implications for increased fishing activities, potentially impacting its population. This research aimed to explore the biological characteristics of M. cordyla landed at the Lempasing Fishing Port, Bandar Lampung, providing fundamental insights for fisheries resource management in the waters of Lampung Bay. Using a quantitative descriptive method, the sampled fish has been analyzed to get size structure, growth type, and fish condition factors based on length and weight data collected from M. cordyla landed weekly. Between April and June 2022, a total of 300 samples were collected, with length ranging from 230 to 430 mm TL, with the largest count (77 individuals) in the 314-334 mm interval. M. cordyla has an allometric negative growth pattern in Lampung Bay, with a growth coefficient (b) value of 2.47. Fish condition factor values ranged from 0.71 to 1.33, with June having the highest average value of 1.03. This information contributes greatly to a better understanding and long-term planning for the management of this fish population.Keywords: Allometric; Condition Factor; Length-Weight Relationship; Pelagic Fish; Aquatic Resources Management

Some biological aspects of chacunda gizzard shad, Anodontostoma chacunda (Hamilton, 1822) from the Bay of Bengal, Bangladesh

Anodontostoma chacunda is a commercial fish species in the market and is usually consumed in fresh, smoked, and dried forms. This study investigated the population structure, length-weight relationships (LWR), condition factor (KF), size at sexual maturity (Lm), and breeding season of A. chacunda in the Bay of Bengal, Bangladesh, using the data collected from January to December 2020. A total of 1061 individuals were collected in the sampling period with the help of fishers. Total length (TL) and body weight (BW) were measured using a measuring board and an electronic balance. The TL ranged from 12.50 to 26.70 cm. The allometric coefficient (b) value was 3.34, indicating positive allometric growth in this species. The fish is in good condition, evidenced by its condition factor (KF) ranging between 0.88 and 1.73. Maturity size ranged from 15.40 to 16.80 cm (TL) based on three distinguished models. Spawning time lasts from January to May and from September to December. The peak spawning time was December of A. chacunda in the Bay of Bengal. This information could prove valuable for fisheries researchers and biologists, facilitating efforts toward the conservation and sustainable management of this species.

Length-weight Relationship, Condition Factor and DNA Barcoding of Bonylip Barb, Osteochilus vittatus (Valenciennes, 1842) in Dampelas Lake, Central Sulawesi, Indonesia

Dampelas Lake, also known as Talaga Lake, in Central Sulawesi Indonesia, lacks data on fish communities, especially biological aspects, including a wild population of bonylip barb Osteochilus vittatus (Valenciennes, 1842). Locally known as ikan nilem, this freshwater fish commodity is not native to Sulawesi. The purpose of this research was to analyze the length-weight relationship, condition factor and DNA barcode of the bonylip barb population in Dampelas Lake. Bonylip barb specimens (101 males and 78 females) were collected from Lake Dampelas during July 2023 using fish traps. The total length and weight ranges were 57-211 mm and 3-107 g. Length-weight relationships were W = 3×10-5 L2,8219 (males); W = 3×10-6 L3,2574 (females); and W = 1,1×10-5 L3,0176 (both sexes combined), indicating an isometric growth pattern. Condition factor ranged from 0.471-1.652 with similar mean values for males (1.01) and females (1.02). DNA barcodes for Lake Dampelas bonylip barbs nested in one of four O. vittatus clades, indicating a need for reviewing Osteochilus taxonomy. Most adult females had spent gonads, indicating seasonal spawning, with implications for developing an economically viable fishery which could also help control this non-native species in Dampelas Lake.Keywords: Cyprinidae, freshwater fisheries, growth pattern, introduced fish, mitochondrial DNA

Errors in estimating reproductive parameters with macroscopic methods: a case study on the protogynous blacktip grouper Epinephelus fasciatus (Forsskål 1775).

A size-based, histological analysis of the reproductive life history of the blacktip grouper, Epinephelus fasciatus (Forsskål 1775), was conducted in Indonesia to evaluate the error rate associated with macroscopic reproductive analysis. Histological results indicated that E. fasciatus was protogynous with female L50 at 13.4 cm total length (LT) and a size at sexual transition of 22.0 cm LT. The weight-length relationship for the species was W = 0.011 L3.13. Overall sex ratios were significantly female biased, operational sex ratios were significantly male biased, and sex ratios of mature individuals varied predictably with length from female to male dominance as size increased. No significant relationship between length and batch fecundity was found. The population has a spawning period from February to August. Overall, 54.4% of macroscopic evaluations were incorrect compared to histological results. Of the errors, 14.8% were a failure to detect ovotestes, 12.7% were classifying non-gonadal tissue as ovary or testis, 12.2% were misclassifying sex, and 12.7% were misclassifying maturity status. However, the largest source of error (47.7%) was from misclassifying both sex and maturity status. Of these, 92.9% were macroscopically classified as immature females, but were histologically confirmed to be mature males. Compared to histological results, the only accurate macroscopic results were the absence of a sex-based difference in weight-length relationship and spawning seasonality estimated by a gonadosomatic index (February-June). The use of macroscopic methods to estimate reproductive life-history parameters for sex-changing reefes fish may introduce significant inaccuracies and misinterpretations. Of the parameters estimated by histological methods, size at maturity, size-specific sex ratios, and spawning seasonality have the greatest potential to inform local fishery management policy.

Length-weight relationship and condition factor of Micralestes eburneensis populations from the Cavally River in Côte d’Ivoire

This study aims to show the effect of anthropogenic pressures on populations of Micralestes eburneensis caught in the River Cavally in Côte d’Ivoire. Sampling took place from April 2015 to May 2017. The fish caught came from experimental and artisanal fisheries. The length-weight relationship and condition factor were determined using the equations P = aLSb and K = 100*P/LS, respectively. A total of 349 individuals with a standard length of between 48 mm and 82 mm and a mass ranging from 3 g to 10 g were caught. The coefficient of determination (r2) values recorded ranged from 0.66 to 0.88. The estimated allometry coefficients for M. eburneensis were 2.81, 2.55 and 2.42 upstream, in the mining zone and downstream respectively. The condition factors of M. eburneensis individuals sampled in the Cavally river fluctuated between 0.66 and 1.39 with a median value of 1.05. The lowest values (K = 0.66 - 0.88) were recorded during the dry season. The size range in the three best-represented sampling areas is between 66 and 74 mm (standard length). This study contributes to our knowledge of the biology of M. eburneensis and provides a specific database on the length-weight relationship and condition factor of the species M. eburneensis from the Cavally River.

LENGTH-WEIGHT RELATIONSHIPS OF THE ESTUARINE FISH SPECIES IN THE SECOND LARGEST MANGROVE AREA IN THE WORLD, BRAZIL

Length-weight relationship (LWR) parameters are necessary to understand the life cycle of fish to describe the biological aspects of species. In this sense, LWRs were determined for 17 estuarine species from the second largest mangrove area in the world, Northern Brazil. The sampling was carried out during the dry and wet seasons of 2015 and 2018 in 3 estuaries described as conservation units in the rivers Pará, Caeté, and Parnaíba. Fish were collected by using manual beach seine, block nets and sieves. Overall 488 specimens were analyzed using the equation W = a TLb. The a values ranged from 0.000001 to 0.000019 and b values ranged from 2.7230 to 3.2821. This study brings new data on estuarine fish from Brazil with additional information contributing to the conservation and management of the fish stocks.

Allometry and condition factor of Faunus ater (Cerithioidea: Pachychilidae) from An Estuarine Habitat of Kerala, Southern India

Faunus ater is a pachychilid gastropod known to inhabit brackish water habi-tats of Western Indo-Pacific countries. This study aimed to analyse the mor-phometric relationships and condition factor of F. ater collected from the Eda-va-Nadayara brackish water lake of Kerala, India. Hydrographic parameters of sampling stations were recorded. A total of 1,522 specimens were collected every month from March 2019 to February 2020. The mean values recorded for total length, shell width, body whorl length, opercular length, opercular width, and total weight were 45.38±13.44 mm, 14.47±3.88 mm, 20.81±5.83 mm, 7.71±3.08 mm, 4.62±1.62 mm, and 6.97±3.72 g, respectively. The length-weight relation was obtained as Log W= -1.005+2.871 Log L. The b value (<3) indicated a negative allometric growth of the organism. Regression analysis of other morphometric measurements also showed a positive correla-tion (P<0.001). The analysis of Fulton’s condition factor indicated a state of well-being of F. ater in this habitat, with condition factors ranging from 5.87 to 6.99 spatially and 5.48 to 7.00 temporally. This study provides the first detailed investigation of morphometric relationships and condition factors in F. ater.

Length-Weight relationship and condition factor of Lutjanus peru and L. guttatus from the Gulf of California Mexico.

Fulton’s condition factor (k) and the length-weight relationship (LWR) are the most important biological tools with respect to basic aspects of fish population dynamics; they are applicable to strategic plans for the conservation and management of fisheries. A total of 478 snappers Lutjanus peru and L. guttatus were analyzed in Santa Rosalía, Baja California Sur, in the Gulf of California. The total length of Lutjanus peru ranged from 21 to 55 cm, and weight ranged from 215 to 1,920 g, whereas total length of L. guttatus ranged from 21 to 59 cm, and weight ranged from 290 to 1,675 g. The LWR and condition factor were estimated for the two species and intraspecific factors were analyzed (sex, season, maturity stage) using Bayesian hierarchical models with random effects. The parameters of the LWR equation were similar for the two snapper species (α≈0.026 and β ≈ 2.8); they both presented negative allometric growth (p(β<3)>85%). The L. peru growth rate was greater in the warm season (p(βwarm>βcold)≈97%), whereas this difference was not as evident in L. guttatus (p(βwarm<βcold)≈72%). The condition factor k was greater than 1 for all categories in the two species (p(μk)=100%), which suggests that they keep a good body condition. This indicates that L. peru and L. guttatus in Santa Rosalía experience environmental conditions that benefit their body condition, as a function of year-round food availability. This information is useful for future conservation studies and for monitoring snapper captures, as most L. peru individuals caught were sexually immature.

Ommastrephes caroli (Cephalopoda: Ommastrephidae) from the Adriatic Sea: Morphometry, Age, and Genetic Characterization

This study gives the first data on the body and beak morphometric characteristics, age, and genetic structure of neon flying squid, a rarely caught cephalopod in the Adriatic Sea. We identified specimens as recently resurrected Ommastrephes caroli species using two mitochondrial markers, 16S ribosomal RNA gene and cytochrome c oxidase subunit I gene. Overall, 23 juveniles (3 females, 3 males, and 17 unsexed), with a dorsal mantle range of 65–152 mm, were caught in September 2020 in the waters of the Korčula Channel, island of Palagruža, and island of Jabuka, thus providing the most abundant sample of this species in the Mediterranean waters. The length–weight relationship showed an isometric growth. The results of the beak/length regressions suggest hood length is a useful characteristic for biomass estimation studies, as it showed a good linear fit to the dorsal mantle length. Statolith growth increments were easily visible and statolith microstructure analysis was successfully used to determine the age of 22 individuals. The estimated age ranged from 36 to 64 days (mean = 48 days). The back-calculation analysis showed that the squid hatched during July and August 2020, indicating that O. caroli spawns during the warmer, summertime period. Considering the size and age of the caught individuals, the Adriatic Sea could represent a potential feeding ground for this species. The genetic structure analyses indicate the existence of separate Atlantic and Mediterranean/Adriatic subclusters; however, this warrants further investigation.

Determination of the Length-Weight Relationship and Otolith Biometry Characteristics of Scorpaena scrofa (Linnaeus, 1758) in the Çanakkale Region

This study, conducted from October 2019 to September 2021 in the regions of the Çanakkale Strait and the Northern Aegean incleuding, Kepez, Kumkale, Yeniköy, Dardanos, Güzelyalı, Morto Bay, and Saros Bay. 162 individuals of the species Scorpaena scrofa examined. The total weights and lengths of the individuals were recorded. The average otolith weights of female and male individuals were found to be 0.023 g and 0.023 g, respectively (P

Length-Weight Relationship and Condition Factor of Synodontis schall (Bloch & Schneider, 1801), from Roseires Reservoir, Sudan

This study was carried out to investigate the length-weight relationship and condition factor of the Mochokid catfish S. schall, a commercially important fish species in the Roseires reservoir on the Blue Nile, Sudan. A total of 643 specimens were collected using the multi-filament gillnets of mesh sizes (4.0, 8.0, 10.0, and 12.0 cm) and twine (No. 2 and 12) during the period from November 2015 to October 2016; Samples were collected from four sites namely: Awal Bab, Elregiba, Kirma, and Wad El Mahi.; The length and weight of sampled fish were measured and recorded on the sampling sites and used to determine a length-weight relationship. The growth coefficient (b) ranged from 1.196 to 2.649, with moderate to high correlations (r) between 0.437 and 0.798. Values of (b) were less than 3 indicating a negative allometric growth pattern, whereas weight increased at a lower rate than length. The condition factor (K) ranged from 1.966 ± 0.696 to 3.856 ± 3.856, suggesting the fish were in good health condition throughout the sampling sites. The findings of this study provide valuable insights into the biological aspects of S. schall, which can form the basis of sustainable management and conservation policy for the fishery resource of this economically important fish species in the Roseires reservoir.

Studies on sex ratio, condition factor and patterns of phenotypic estimation in stock identification of snow trout, Schizothorax esocinus Heckel, 1838 inhabiting the colder Indian Himalayan region

Schizothorax esocinus, a nutrient-rich food fish offered in Asian countries, is rapidly declining due to severe fishing pressure and pollution in its wild environment, requiring active conservation strategies. Our study examined 196 specimens to elucidate critical biological parameters including sex ratio, length-weight relationships (LWRs), Fulton's condition factor (K) and morphometric-meristic parameters. The general sex ratio was not substantially departed from the predicted value of 1 : 1, with the exception for the month of May, where χ2 = 4.15 which is greater than the calculated value of 3.84. The correlation between the length and weight was reported as Log W = 0.134209 + 2.5218 log L for males, Log W = 0.19173 + 2.6751 log L for females and Log W = 0.162116 + 2.594 for combined sexes. Schizothorax esocinus demonstrated a negative allometric growth as indicated by the allometric parameter b for the LWR. The two sexes showed no significant differences in morphometric measures. So, this study included combined-sex regression analysis. These comprehensive findings highlight the critical need for conservation efforts in India and neighbouring countries to preserve this valuable fish stock for future generations.

Living between sand and waves: Age and feeding habits of sand sole (Pegusa lascaris, Risso 1810) and brill (Scophthalmus rhombus, Linnaeus, 1758) on the beaches of the Gulf of Cádiz (Southwest Iberian Peninsula)

Within ecosystems that are used as nurseries, surf zones are crucial for many species due to the protection and sustenance these areas provide. Many commercially important species live in these zones during their early years, including the sand sole (Pegusa lascaris) and the brill (Scophthalmus rhombus). The objective of this study was to determine the age and feeding habits of individuals from both species living in the surf zone, as well as any potential variations with the environmental variables such as time of the day, lunar phases or season. The average size was 15.66 ± 3.71 cm (TL) for the sand sole and 11.49 ± 5.66 cm (TL) for the brill. The length-weight relationship for the sand sole was TW = 0.005*TL3.230 (parameter a: 95 % C.I.: 0.004–0.006 and parameter b: 95 % C.I.: 3.134–3.326), while for the brill it was TW = 0.013*TL3.048 (parameter a: 95 % C.I.: 0.012–0.016 and parameter b: 95 % C.I.: 2.988–3.108). In both the sand sole (92.4 %) and the brill (85.6 %), the most abundant age classes were 0+ and 1+, with significant differences in the abundance of age classes, depending on the season, in the case of the brill. The sand sole primarily feeds on cumaceans and bivalves, with significant variations in diet based on the time of the day, moon phases, and season, whereas the brill preys on mysids. This research provides new insights into how both species utilize the surf zone, using these areas as nurseries in their early years of life. This underscores the importance of these zones and the potential of the ecosystem services they offer.

Length-weight Relationship and Relative Condition Factor of Paratrypauchen microcephalus (Bleeker, 1860) along the Mumbai Coast

Length-weight Relationship and Relative Condition Factor of Paratrypauchen microcephalus (Bleeker, 1860) along the Mumbai Coast

Biometric Characteristic Study of Green Lipped Mussel, Perna viridis (Linnaeus, 1758) From Malad Creek, Mumbai, India

Biometric Studies are essential to understand the growth rate of the species which helps understand the growth patterns, reproduction rate and population distribution of the species. Growth patterns of molluscs help in evaluating their production potential and energy flows through populations and their distribution. Perna viridis (Linnaeus, 1758) commonly known as the green-lipped mussel or the Asian green mussel belongs to the family Mytilidae. It is distributed along the Indo-Pacific region. They are attached to the rocky substratum along the coast, in the intertidal region. The Biometric Analysis and Length-Weight Relationship study was carried out on Perna viridis (Linnaeus, 1758) to understand their growth rate and population distribution through the Coast of Mumbai. A total of 100 samples were used in this study. The correlation between the Total Weight of the Shell with the organism (WSO) to the Shell Length (SL), Shell Width (SW) and Shell Height (SH) and the correlation between the Soft Tissue Weight of the Organism (WO) to the Shell Length (SL), Shell Width (SW) and Shell Height (SH) gave an idea about the growth factors. The Relative Condition Factor was determined by equation W = aLb. The b values of each correlation showed negative allometric growth with p value to be p<.001 with same significance in Pearson Correlation test. The Relative Condition Factor of WSO-SW and WSO-SL was observed to be above 1 indicating good growth conditions. Thus, biometric studies are a useful tool in study of Perna viridis (Linnaeus 1758) biology, physiology, ecology, growth potential, stock assessment, genetics and breeding of Perna viridis (Linnaeus, 1758).

Length-Weight Relationships of Eight Fish Species Collected as Bycatch from Deep-Sea Shrimp Trawls Operated in the Arabian Sea

Length-Weight Relationships of Eight Fish Species Collected as Bycatch from Deep-Sea Shrimp Trawls Operated in the Arabian Sea

Stock assessment and management recommendations of Indo-Pacific king Mackerel (Scomberomorus guttatus) in the upper Bay of Bengal

ABSTRACT This explorative research aimed to elucidate the stock profile and optimum catch limit of the king mackerel (Scomberomorus guttatus) stock by collecting data in the upper Bay of Bengal. This study used three length-based methods and a catch-based method to determine the growth parameters and biological reference points (BRPs) of king mackerel. A negative allometric growth pattern (b = 2.50) was observed in the length–weight relationship. The life history parameters were estimated as L∞ = 117.35 cm, k = 0.42 year−1 and the mortality estimates were the total mortality (Z = 1.18 year−1), natural mortality (M = 0.46 year−1) and fishing mortality (F = 0.72 year−1). The results show that this fishery is currently likely to be overfished due to overexploitation (F/M = >1) and the stock’s spawning biomass (SPR = 9%) is substantially lower than the target reference point because most of the catch (70%) was found to have under the maturity level. The recommended minimum total length for the catch is >59 cm and a yearly catch limit of 2400 mt as OFL (Over Fishing Limit) for the next ten years coordinated with the existing precautionary measures such as an annual fishing ban to raise the stock’s biomass over the BMSY level for maintaining sustainable yield of 4516 mt as MSY.

Effects of low temperature on growth and metabolism of larval green sturgeon (Acipenser medirostris) across early ontogeny.

Southern Distinct Population Segment (sDPS) green sturgeon spawn solely in one stretch of the Sacramento River in California. Management of this spawning habitat is complicated by cold water temperature requirements for the conservation of winter-run Chinook salmon. This study assessed whether low incubation and rearing temperatures resulted in carryover effects across embryo to early juvenile life stages on scaling relationships in growth and metabolism in northern DPS green sturgeon used as a proxy for sDPS green sturgeon. Fish were incubated and reared at 11°C and 15°C, with a subset experiencing a reciprocal temperature transfer post-hatch, to assess recovery from cold incubation or to simulate a cold-water dam release which would chillrearing larvae. Growth and metabolic rate of embryos and larvae were measured to 118days post hatch. Reciprocal temperature transfers revealed a greater effect of low temperature exposure during larval rearing rather than during egg incubation. While 11°C eggs hatched at a smaller length, log-transformed length-weight relationships showed that these differences in developmental trajectory dissipated as individuals achieved juvenile morphology. However, considerable size-at-age differences persisted between rearing temperatures, with 15°C fish requiring 60days post-hatch to achieve 1g in mass, whereas 11°C fish required 120days to achieve 1g, resulting in fish of the same age at the completion of the experiment with a ca. 37-fold difference in weight. Consequently, our study suggests that cold rearing temperatures have far more consequential downstream effects than cold embryo incubation temperatures. Growth delays from 11°C rearing temperatures would greatly increase the period of vulnerability to predation in larval green sturgeon. The scaling relationship between log-transformed whole-body metabolism and mass exhibited a steeper slope and thus an increased oxygen requirement with size in 11°C reared fish, potentially indicating an energetically unsustainable situation. Understanding how cold temperatures affect green sturgeon ontogeny is necessary to refine our larval recruitment estimations for this threatened species.

Spatial and Temporal Effect of Environmental Factors on the Length-Weight Relationship of the Bali Sardinella (Sardinella lemuru Bleeker, 1853) in Bali Strait Water

Spatial and Temporal Effect of Environmental Factors on the Length-Weight Relationship of the Bali Sardinella (Sardinella lemuru Bleeker, 1853) in Bali Strait Water