Length-weight Relationship Equations Research Articles

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.

Early-Life Population Parameters and Hatch-Date Analysis of Sharpsnout Seabream (Diplodus puntazzo Walbaum, 1792) Juveniles in the Sea of Marmara, Türkiye

This research aims to determine early-life population parameters and hatch date of sharpsnout seabream (Diplodus puntazzo Walbaum, 1792) juveniles using microstructure analyses of sagittal otoliths collected from the Sea of Marmara, Türkiye. Specimens were collected using an experimental beach seine at 12 stations from November 2021 to March 2022. The mean catch per unit effort (CPUE) was 1.1 individuals per haul, with 44.4% of the total D. puntazzo specimens collected at the Erdek Station. A negative allometric growth was calculated from the length-weight relationship equation (W=0.0178L2.698). The daily age ranged between 39 days-1 and 141 days-1, with a mean of 78.9 ± 2.29 days-1. The daily growth rate and mortality ratio were calculated as 0.213 mm/day and 4.38%, respectively. The hatching mainly occurred in September and October.

Age, Growth, and Maturity of Painted Comber Serranus scriba (Serranidae) from the Crimea Region, the Black Sea

The painted comber Serranus scriba, a subtropical marine fish species assigned to the famiy Serranidae in the Black Sea is insufficiently studied. It is a simultaneous hermaphrodite fish. Data on age, growth, and maturity of the painted comber inhabiting the Black sea area around Crimea, including its spatial variation within the entire habitat range are reported. Overall, 537 specimens caught from July to October 2022 are analyzed. The biggest specimen ever caught in the Black Sea with 26.1 cm total length and 265.1 g weight at the age of 15 years was registered. The values for the von Bertalnffy equation parameters were estimated. Thus, asymptotic length, asymptotic weight, and growth constant made up 28.3 cm, 358.6 g, and 0.17 year−1, respectively. The exponent of 3.10 in the length-weight relationship equation (positive allometry) was estimated. Maturity was defined in 50% spesimens at 12.0 ± 0.2 cm total length in the third year of life. It was ascertained that spatial variation in the life history traits for the specimens is weakly expressed. The painted comber inhabiting the Black Sea is slightly different from the representatives of this species found in the Aegean and Adriatic Seas in age, size, and growth. In addition, the biggest and faster-growing specimens are recorded more often under the low-latitude climate conditions, in the water areas off Egypt and the Canary Islands.

Assessing fishery status and sustainable exploitation of spotted seabass (Dicentrarchus punctatus) in Bardawil Lagoon, Eastern Mediterranean, Egypt

The growth and population parameters of spotted seabass (Dicentrarchus punctatus) in Bardawil Lagoon were investigated to assess their fishery status and propose concrete recommendations for sustainable exploitation. The samples (n = 271) were collected from commercial catches during 2021. As revealed by examining the otoliths, D. punctatus has a short life span of a maximum of four years based on the mean lengths of 20.2, 25.3, 29.7, and 33.5 cm for age groups from I to IV, respectively. The total length-weight relationship equations were W = 0.0120TL2.9672 for males, W = 0.0127TL2.9486 for females and W = 0.0124TL2.9563 for the combined sexes. The von Bertalanffy growth function was Lt = 40.50(1-e-0.38(t+0.66)). The study determined the total and natural mortality rates as 1.58 and 0.79 year−1, respectively, with an exploitation rate (E) of 0.49, which was found close to the optimum value (0.5). However, based on management policies, E was greater than the value corresponding to 50% relative biomass per recruit (E0.5), which indicates that the current fishing effort is unsustainable. Therefore, to maintain the biomass of spawning stocks, the study recommends a 22.4% reduction in the current exploitation rate through the application of fishing regulations that decrease fishing efforts. Such recommendations can help ensure the sustainable exploitation of spotted seabass in Bardawil Lagoon.

Length-Weight and Length-Length Relationships and Condition Factor of An Endemic Fish Species (Capoeta tinca (Heckel, 1843)) Inhabiting Bayat Pond (Ankara, TÜRKİYE))

The aim of this study is to determine the length-weight relationship, length-length relationship, and Fulton’s condition factor (K) of Capoeta tinca, which is endemic to Turkey. A total of 52 samples were obtained from Bayat Pond in 2017. The total length (TL) of the samples ranged between 20 and 34 cm. Total weights (W) of they also varied from 85 to 446g. Strong correlations were found between length and weight. In the length-weight relationship equation, a and b was found as 0.0144 and 2.9028, respectively. b value was not statistically different from 3 (t-test, P>0.05). Therefore, this species showed isometric growth in the Bayat Pond. The value of Fulton’s condition factor was 1.0485. Total length - Fork length (FL), Total Length - Standard length (SL) and Fork length - Standard length conversion equations were calculated. There was a high correlation between all length types. In this study, the length-weight relationship, length-length relationship, and Fulton's condition factor values of Capoeta tinca inhabiting Bayat Pond were determined for the first time.

Estimation of Some Population Parameters of Squalius cephalus (Linnaeus 1758) in Tabakane Stream (Ordu-Turkey)

The purpose of this study is to estimate some population parameters such as length-length and length-weight relationships and condition factor of Squalius cephalus individuals living in Tabakane Stream (Ordu-Turkey). A total of 326 S. cephalus individuals were sampled from Tabakane Stream, located in Ünye district in the Ordu province, by using an electroshocker. It was determined that the mean total, fork and standard lengths of the fish samples were 7.58±0.143 cm, 7.06±0.133 cm, and 6.30±0.121 cm, respectively, and their average weight was 6.05±0.322 g. The length-weight relationship of the species was calculated as W=0.0088TL3.0648 R²=0.993. As a result of our analyzes, it was determined that the S. cephalus population in Tabakane Stream showed a positive allometric growth. In the present study, it was determined that the 95% confidence interval of the b value in the length-weight relationship equation was between 3.0566-3.0678 and there was a strong relationship between body weight and total length. Relationship equations between total, fork and standard lengths were calculated as TL=1.0724FL+0.0086 (r2=0.9978), TL=1.1763SL+0.167 (r2=0.9972), and FL=1.0961SL+0.1529 (r2=0.9979) and it was determined that there are strong relationships between standard, fork and total length measurements of S. cephalus individuals living in Tabakane Stream. It was determined that the condition factor values of S. cephalus ranged between 0.73971 and 1.27570. The average condition factor was 0.99831±0.005. There is no previous study on the population of S. cephalus living in Tabakane Stream. In this study, the condition factor, length-weight and length-length relationships of S. cephalus in this habitat were reported for the first time.

Relationships between length-weight, length-length, and fish length to otolith morphometry in Rita rita (Hamilton, 1822)

The present study deals with fish length-weight, length-length, length-otolith size and length-otolith weight relationships in Rita rita. Specimens (N = 117) were collected monthly from September 2018 to August 2019 from Narora site of the River Ganga, India. The slope (b) in length-weight relationship equation was 2.40, suggesting a negative allometric growth pattern. The Student’s t-test showed no significant differences in the size of right and left otoliths in Rita rita, therefore, a single linear regression based on left otoliths was used. Fish length was plotted against otolith length, otolith height and otolith weight. The linear regression model was found to fit the data well for fish length to otolith size. Fish length was positively correlated with otolith height (R2 = 0.97), otolith length (R2 = 0.94) and otolith weight (R2 = 0.91). The mean value of condition factor was 1.13, which suggested a good condition of the target fish species in the River Ganga. Findings of this study could be used to study the population characteristics of Rita rita, and to explore the food and feeding biology of piscivores based on correlating the otolith morphometry of the prey items to the fish length at age.

Population Dynamics of the Caroun Croaker Johnius carouna (Cuvier, 1830) in Coastal Fishing Ground in the Middle Gulf of Thailand

The stock status of coastal species is currently of high concern among the people. In the Gulf of Thailand, Croakers are important economic species commonly found in the coastal fishing ground, especially in Nakhon Si Thammarat province. The population dynamics of the Caroun croaker, Johnius carouna (Cuvier, 1830), was investigated using length-frequency distribution data collected from February 2019 to January 2020. The length-weight relationship equation suggested that J. carouna is isometric growth. The asymptotic total length (L∞) and curvature growth (K) were 22.28 cm and 0.72 year-1, respectively. Based on L∞ and K, the total mortality rate during the study period was estimated at 3.66 year-1; natural mortality and fishing mortality rates were estimated at 1.62 and 1.74 year-1, respectively. While biological data revealed that matured size was 15.3 cm, the fishing data suggested that the average catch size (15.12 cm) was slightly smaller than the matured size. The exploitation rate was 0.52 year-1. The result from this research suggests that current fishing pressure is slightly high. This study suggested that increasing catch size by increasing mesh size of gillnets seems to be a better solution to improve J. carouna stock in Thasala fishing ground in the future. HIGHLIGHTS The first report onJohnius carouna fishery biology in coastal fishing ground in the middle Gulf of Thailand Johniuscarouna is an isometric fish Matured size of Johniuscarouna is 15.3 cm Current fishing pressure on Johniuscarouna is slightly high GRAPHICAL ABSTRACT

Some population characteristics of Oxynoemacheilus angorae (Steindachner, 1897) from the Perşembe Plateau meandering streams in Ordu, Turkey

Abstract The aim of the current study was to determine the length-weight relationship (LWR) and length-length relationship (LLR) with condition factor (K) values for Oxynoemacheilus angorae from the Perşembe Plateau meandering streams in Ordu, Turkey. A total of 65 fish specimens, which were caught with electrofishing gear, were examined. Fish standard length (SL), fork length (FL), total length (TL), and body weight (W) were determined. There were no statistical differences between the measurements of male and female O. angorae specimens; therefore, the female and male specimens were evaluated together in the current study. The LWR equation and determination coefficient of O. angorae were W = 0.014 TL2.7359 (r2 = 0.9659). The 95% confidence interval of the b value for the O. angorae specimens from the Perşembe Plateau meandering streams was 2.7261 to 2.7435. In the present study, it was determined that O. angorae specimens showed negative allometric growth. Calculations of O. angorae TL-SL, TL-FL, and FL-SL relationship equations and determination coefficients were as follows: TL = 0.2091+1.1646 SL, (r2 = 0.986); TL = 0.1341+1.0301 FL (r2 = 0.9914); and FL = 0.0998+1.1261 SL, (r2 = 0.9868), respectively. A new maximum total length was recorded for O. angorae in this study. The average condition factor value of O. angorae was 0.9954. This value could have indicated that this species was encountering some problems in this habitat. The O. angorae parameters determined were the first data reported for the Perşembe Plateau meandering streams in Ordu, Turkey (Middle Black Sea Region).

Karadeniz’in Sinop kıyılarında Mnemiopsis leidyi A. Agassiz, 1865 (Ctenophora: Lobata)’nin boy dağılımı ve boy-ağırlık ilişkisi parametreleri

Some population parameters of gelatinous macrozooplankton species, Mnemiopsis leidyi, were studied in the present study carried out from January 2008 to December 2008 along the coasts of Sinop in the Black Sea. A total of 980 M. leidyi specimens were measured and weighed. The estimated average length and weight of the species were 3.2±0.060 cm and 7.3±0.250 g, respectively. The observed maximum and minimum lengths were 10.8 cm and 0.2 cm. The maximum and minimum weights measured were 63 g and 0.1 g. The length-weight relationship equation for M. leidyi was determined to be W = 0.7905L1.6406.

Improving the size-selectivity of trammel net for Pomadasys stridens and Gerres oyena in Suez Bay, the Gulf of Suez, Red Sea

Size selectivity of the trammel net for Pomadasys stridens and Gerres oyena in Suez Bay, Gulf of Suez, Red sea, was estimated by comparing three mesh sizes 34, 37 and 40 mm for the inner layer of the trammel net. The SELECT model was used to estimate the selectivity curve. Length frequency data were fitted by five models: normal scale, gamma distribution model, normal location, lognormal distributions model, and bi-normal model. The results revealed that the best fit model of selectivity curve of the trammel nets data for Gerres oyena was obtained by the and bi-normal model, whilst the Log-normal model gave the best fit for Pomadasys stridens. The length-weight relationship equations were estimated to be W = 0.027 × L2.735 with r2 = 0.97 for Pomadasys stridens and W = 0.050 × L2.470, r2 = 0.93 for Gerres oyena. The study concluded that the mesh size of the trammel nets used in Suez Bay fishery should not be less than 40 mm especially for Pomadasys stridens and Gerres oyena to protect their stocks from overfishing.

Biological aspect and dynamic population of fringescale sardine (Sardinella fimbriata: Valenciennes, 1847) in Prigi waters Trenggalek, East Java, Indonesia

Fringescale sardine (Sardinella fimbriata) is one of important species caught in Prigi waters, Trenggalek, East Java. The existence of fringescale sardine as marine fisheries commodity plays an important role in Prigi fisheries community. This research was conducted in Prigi waters from December 2018 to July 2019 aimed to determine the biological aspects, to illustrate some dynamic population parameters, and to identify food composition. This study applied a descriptive method and random sampling for data collection. There were 1,375 fish have been assessed with total length (TL) ranging from 10 cm to 20.4 cm. Results indicated that growth patterns of the fish was negative allometric with length weight relationship equation was W = 0.014L2.804. Sex ratio of male and female obtained was 1: 1. The gonad maturity level analysis found that proportion of mature and immature fish was equal. The gonadosomatic index value was ranged from 0.57% to 2.42%. The values of length at first capture and length at first mature were 15.35 cm and 16.07 cm, respectively. The growth rate equation obtained in this study was Lt = 26.75 (1-e0.92 (t+0.178)). Mortality rates, total and fishing were 1.709 and 0.286, respectively, while the exploitation rate was 0.167. Additional assessment showed that the main food of the fringescale sardine was phylum Arthropods with index of preponderance (IP) value was 61.5%. It can be concluded that the fish was a plankton feeder and status of the stock was in over fishing condition.

Length-Length and Length-Weight Relationships of Lessepsian Saurida undosquamis from the İskenderun Bay (Eastern Mediterranean, Turkey)

In this study, the length-length and length-weight relationships were investigated for Saurida undosquamis from the Eastern Mediterranean Sea (Turkey). All fish sample lengths and weights were recorded to the nearest 0.01 g and to 0.01 cm, respectively. According to t-test results, there were statistically significant differences between sexes in terms of length and weight (P<0.05) for S. undosquamis; therefore, female and male samples were separately evaluated in the current study. The length-weight relationship equations of S. undosquamis were calculated as W=0.0023TL3.330; W=0.0014TL3.487 and W=0.0020TL3.366 for females, males, and all individuals, respectively. It was found that the “b” value in the length-weight relationship equation was statistically different from 3 (P <0.05). As a result of the analysis, it was determined that S. undosquamis showed positive allometric growth in this habitat. When the length-length relationships of S. undosquamis were examined, they were found that the coefficients of determination ranged from 0.98 to 0.99 and they were also highly significant (P<0.001). This study can help provide the necessary information to ensure the sustainability of fish stocks.

Length-weight and length-length relationships of Red Scorpionfish (Scorpaena scrofa L. 1758) from Aegean Sea (Turkey)

In this study, the length-weight and length-length relationships were investigated for S. scrofa from İzmir Bay, Aegean Sea. All fish sample lengths and weights were recorded to the nearest 0.01 cm and to 0.01 g. The measured total length values for females, males and combined sexes were 16-30.2 cm; 17.7-28 cm and 16-30.2 cm respectively. The weight values for females, males and combined sexes were 73.20-441 g; 89.80-378 g and 73.20-441 g respectively. According to t test results, there were no statistically significant differences for S. scrofa species (P˃0.05); therefore, female and male samples were evaluated together. The length-weight relationship equations as y=0.016x2.993(r²=0.914) for all specimens. The ‘b’ value of LWR was not significantly different from 3.0 and their growth type was isometric. Total length-standard length relationship equations were determined as y=1.287x+0.112 (r²=0.97). This study is helpful in providing information about length-weight and length-length relationships and the current study can be useful to compare stocks of the species in the different habitats.

Length-weight and length-length relationships for three species of Squalius (Cyprinidae; Leuciscinae) from the Caspian Sea, Namak and Tigris basins of Iran

Length-weight and length-length relationships were estimated for three species of the genus Squalius. These fish were sampled from the Caspian Sea as well as the Namak and Tigris basins of Iran. Sampling took place between July 2009 and August 2010 using a seine net (15 m long, 2 m width and 5 mm mesh size). The values of the b parameter in the length-weight relationship equations were determined as 3.37 for S. turcicus, 3.25 for S. namak and 3.14 for S. berak (b > 3).

Length-weight relationships of two native fish species from the upper reaches of Nujiang River, Southwest of China

The length–weight relationships (LWRs) were determined for two native cyprinid fishes: Poropuntius opisthopterus (Wu, 1977) and Raiamas christyi (Boulenger, 1920) collected from the upper reaches of Nujiang River (31°33′29″N; 92°55′58″E), Southwest of China. A total of 162 specimens were collected quarterly between March 2015 and November 2016. Fish were sampled by electrofishing in 12 wadable sites with maximum water depth 60–70 cm. The b values parameter in the length–weight relationship equations were calculated as 2.90 for P. opisthopterus and 3.45 for R. christyi. This study represents a new maximum standard length record for P. opisthopterus.

Length-weight relationship and condition factor of Tade gray mullet, Chelon planiceps (Valenciennes, 1836) from Hooghly-Matlah Estuary, West Bengal, India

Tade gray mullet (Chelon planiceps) forms a lucrative fishery in the Hooghly-Matlah estuarine system. During eight months of investigation 232 specimens were examined to study length-weight relationship and relative condition factor (Kn). The length and weight of fish was varied from 41 to 283 mm and 0.81 to 208 g respectively. Two length-weight relationship equations were obtained from the analysis, W=0.0000397L2.952 for <187 mm size group and W=0.0000406L2.834 for >187 mm size group. The size at first maturity was recorded as 187 mm. The b value was not significantly different from 3 indicating isometric growth. The monthly mean Kn for the male and female were 1.041–1.125 and 1.009–1.236 respectively. The highest Kn value was recorded in July for both the sexes, which may be due to advance maturity stages. The present study will be useful in the context of biological management of mullet fishery as well as to find out aqua-farming potential of Tade gray mullet.

Length-weight relationship and condition factor of Tade gray mullet, Chelon planiceps (Valenciennes, 1836) from Hooghly-Matlah Estuary, West Bengal, India

Tade gray mullet (Chelon planiceps) forms a lucrative fishery in the Hooghly-Matlah estuarine system. During eight months of investigation 232 specimens were examined to study length-weight relationship and relative condition factor (Kn). The length and weight of fish was varied from 41 to 283 mm and 0.81 to 208 g respectively. Two length-weight relationship equations were obtained from the analysis, W=0.0000397L2.952 for <187 mm size group and W=0.0000406L2.834 for >187 mm size group. The size at first maturity was recorded as 187 mm. The b value was not significantly different from 3 indicating isometric growth. The monthly mean Kn for the male and female were 1.041–1.125 and 1.009–1.236 respectively. The highest Kn value was recorded in July for both the sexes, which may be due to advance maturity stages. The present study will be useful in the context of biological management of mullet fishery as well as to find out aqua-farming potential of Tade gray mullet.

Length-weight and length-length relationships for six fish species from Zohreh River, Iran

The present study reports Length-weight and length-length parameters for six fish species belonging to four families from the Zohreh River. The weight-length relationships were estimated using the equation W= 𝛼L b . The values of the slope parameter ( b ) varied between 2.72 and 3.72, with a mean±SD of 3.015±0.18. The values b parameter in the length-weight relationship equations were calculated as 2.72 for Arabibarbus grypus (Heckel, 1843), 2.96 for Capoeta trutta (Heckel, 1843), 2.72 for Garra rufa (Heckel, 1843), 3.25 for Aphanius dispar (Ruppell, 1829), 2.91 for Sillago sihama (Forsskal, 1775) and 3.15 for Glyptothorax silviae Coad, 1981. This study presents the first reference on LWR and LLR for these species in Zohreh River.

Một số đặc điểm sinh học của cá chỉ vàng - Selaroides leptolepis (Cuvier, 1833) ở vùng biển Tây Nam Bộ, Việt Nam

Biological characteristics of Yellowstrip Scad - Selaroides leptolepis (Cuvier, 1833) were analyzed by using the fisheries biology data collected in landing sites from 2014 to 2015 in the Southwest Sea of Vietnam. Results indicated that the main lengh of Yellowstrip scad in the Southwest sea was 11.3 cm, in the range of 4.5cm to 15.4 cm. The length-weight relationship equations was W=0,000008L3,154 (male), W= 0,000009L3,114 (female), W=0,00002L2,965 (juvenile). Growth parameters (L∞ and K) of the von Bertalanffy equation were 16.3 cm and 1.2/year, respectively. The length at first maturity of fish (Lm50) was 9.8 cm. Male/Female rate of fish was 1.1. The Yellowstrip scad breeds throughout the year but the spawning peaks are observed from Febuary to April. The total mortality Z=4.24/year, the instantaneous natural mortality due to predation, aging and other environmental causes with M= 2.39/year, the instantaneous fishing mortality caused by fishing F=1.85/year and exploitation rate E= 0.44/year.