Search

Abstract Estimating fish growth in real time has many benefits for indoor aquaculture farms, such as saving labor time and costs, reducing water pollution during feeding, improving feeding activity and determining when to harvest. Hence, this study proposed a visual‐information‐based method for measuring olive flounder (Paralichthys olivaceus) length, using accurate growth tracking for efficient aquaculture management. Using two cameras, an light‐emitting‐diode (LED) grid was placed at the bottom of the water tank to measure fish length. The pixels unit from the fish length in the captured image was converted to centimeters based on the relationship of a pre‐built dataset. A total of 180 lengths were calculated using images captured by the cameras. The average length of each fish acquired from the cameras was calculated separately, and Lagrange's interpolating polynomial algorithm was implemented to calculate the overall length of each fish. This method reduced the computational complexity, and results were obtained more rapidly and in a user‐friendly environment. The power model generated the length–weight relationship, which allowed us to estimate the body weight of each olive flounder based on the length. The proposed approach enabled us to calculate the length of olive flounders with a highly accurate R2 of 0.995.

Graphical Abstract Highlight Research • The results of this research showed that allometric growth in males and females had negative allometric growth characteristics. • The growth condition index in male and female fish is dominated by thin and fat body shapes.The maximum length growth (L∞) and growth speed of males is higher than that of females. • Total mortality and fishing mortality for males is higher than for females, but natural mortality for females is higher than for males. • The exploitation rate of males and females is in the Under-exploitation category because the E value is

The study was conducted in the Terie River between January and April 2022. The objectives of the study were to assess the fish species composition, determine the length-weight relationship and condition factor and assess the water quality of the river using international water quality guideline for aquatic life. Gillnets with different mesh sizes, 4, 6, 8 and 10 cm were used to collect fish specimens in both dry and wet seasons. Immediately after capture, the total length (TL) and total weight (TW) of each individual were measured in centimeters and grams, respectively, and their relationship was determined using the power function. The physicochemical water quality parameters were analyzed using standard procedures and wagtech portable water quality Kits and Secchi Disk apparatus. A total of 667 fish specimens were collected from the Terie River, 410 and 257 in dry and wet seasons respectively. A total of six fish species, Oreochromis niloticus, Labeobarbus intermedius, Labeobarbus nedgia, Labeobarbus beso, Clarias gariepinus, and Ramius loti were recorded. For length-weight relationship and condition factor analysis, more abundant fish species (O. niloticus and L. intermedius) which were found in both seasons were selected. The length and weight relationship of L. intermedius were TW = 0.0073TL3.04 in dry and TW = 0.0337TL2.59 in we season indicated isometric and negative allometric growth respectively. While O. niloticus showed negative allometric growth, TW = 0.096TL2.44 and TW = 0.0335 TL2.76 in dry and wet seasons, respectively. The mean Fulton condition factor (FCF) of L. intermidus were 0.85 ± 0.03 and 0.94 ± 0.25 in dry and wet seasons, respectively. The FCF of O. niloticus was 1.70 ± 0.13 and 1.73 ± 0.12 in dry and wet seasons respectively. Except for ammonia, the physicochemical water quality parameters were with the permissible limit for aquatic life and are suitable for fishes Terie River. The river has commercially important fish specimens that could be used for food security and livelihood improvement. However, there is very limited fishing activity in the river due to less awareness on the value of fishes. Therefore, sustainable fishery development should be done in the river.

Highlight Research • The mitre squid (Uroteuthis chinensis), the Indian squid (Uroteuthis duvaucelii), and the purpleback flying squid (Sthenoteuthis oualaniensis) were identified. • Morphometric differences among three squid species were analyzed. • Microanatomy observations on the shapes of the sucker rings were important for species identification. • Hypoallometric and isometric growth patterns were observed. Abstract Squids play vital ecological and economic functions as keystone species in marine food webs and integral components of global capture fisheries. However, a comprehensive understanding of their diversity and life history characteristics in Indonesian waters is still poorly understood. This study aimed to identify squids that inhabited Java's northern and southern coasts and examine their growth pattern through morphometric analysis. Six hundred eighteen squid samples were collected fishers caught from May to September 2022 in Blanakan and Palabuhanratu Bay, representing two areas of interest. The body size and the shape of sucker rings of squids were observed using morphometric method. Kruskall-Wallis test, Principal Component Analysis, and Spearman's correlation were performed to investigate morphometric variation and relationships. The length-weight relationships were estimated for each species.. This study reported three species of squid on the north and south coasts of Java, namely the mitre squid (Uroteuthis chinensis), the Indian squid (Uroteuthis duvaucelii), and the purpleback flying squid (Sthenoteuthis oualaniensis). There were significant differences observed in ten morphometric variables among the three species of squid (p < 0.05), with fin width, fin length, and sucker ring teeth identified as the key distinguishing feature for the squids. Spearman's correlation indicated stronger associations between mantle and fin variables (Ï = 0.666-0.967, p < 0.05) than those between mantle and head variables (Ï = 0.380-0.864, p < 0.05).Mantle length-weight relationships revealed a hypoallometric growth pattern for U. chinensis and U. duvaucelii, while S. oualaniensis exhibited an isometric growth pattern. The finding of this study provides valuable insights concerning the growth of squids that reflect variation in ontogenic development, trophic ecology, and environmental conditions in Indonesian waters.

For management of fish stocks, assessing the various parameters of population dynamics are regarded as being extremely important. Under this backdrop the population dynamics parameters viz. growth, mortality and recruitment of Pethia conchonius, inhabiting the Dal Lake of Kashmir Himalayas were analysed using FiSAT II software. The analysed specimens were collected from five different sites within the lake and exhibited a total weight range of 0.3 to 6.4 g and a total length range of 3.1 to 7.8 cm. The relative condition factor for the fish was reported to be 1.11. The growth parameter i.e., asymptotic length, age at zero length, growth performance index and growth constant were reported to be 10.0 cm, –0.75 years, 1.48 and 0.30 year–1 respectively. The total mortality of 1.49 year–1, consisting of natural mortality of 0.88 year–1 and fishing mortality of 0.61 year–1 was reported. An exploitation rate of 0.41 is suggestive of a less exploited state of the fish. The length at first maturity was found to be higher than the length at first capture, a condition that can disturb the stock, as such the utility of a net with relatively larger mesh size is advisable. The current research on the population dynamics of P. conchonius can be used as the baseline data for its management practices.

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.

Knowledge about the population dynamics within a specific spatial area is vital for the effective planning and management of important fishery resources. Population parameters, including the asymptotic length (L∞), growth coefficient (K), mortalities (Z, F, and M), recruitment pattern, exploitation level (E), and yield per recruit (Y'/R), of the tropical oyster Magallana bilineata in Mengkabong Bay, Tuaran, Malaysia were analyzed by using the FiSAT software, using on the monthly shell length-frequency data collected from April 2019 to March 2020. A total of 435 oysters with shell lengths ranging from 3.64 to 11.16 cm were analyzed. Habitat water temperature, salinity, dissolved oxygen, hydrogen ion concentration (pH), and chlorophyll concentration were measured at 29.0–33.7 °C, 26.68–35.74 psμ, 3.18–6.99 mg/L, 6.57–8.29 and 1.51–98.93 μg/L, respectively. The logarithmic relationship between the length and weight of Log W = 1.9055 Log L + 0.1049 (R2 = 0.5431) with exponent b of 1.9055 for combined sexes showed a negative allometric growth (b

Biometric evaluation and reproductive biology of Oreochromis niloticus were studied from Geray Reservoir. Between November 2021 and August 2022, 316 O. niloticus specimens were collected from this reservoir. The observed male to female sex ratio was 1:1.14, which was statistically insignificant compared with the hypothetical 1:1 sex ratio (X2 = 1.27, p > 0.05). The length-weight relationship was curvilinear with allometric growth (b < 3) and statistically significant from the expected isometric growth pattern (b = 3). The regression equation for females was TW = 0.0264TL2.72 (r2 = 0.90, n = 168), males (TW = 0.0183TL2.79, r2 = 0.93, n = 148), and combined sexes (TW = 0.0229TL2.76, r2 = 0.91, n = 316). Gonadosomatic index (GSI) ranged from 0.8 to 1.4 (males) and 1.8 to 4.9 (females). The breeding season lasted from March to June, with a GSI peak in April. Fecundity ranged from 279 to 1,528 eggs./fish, with a mean of 1,025 eggs./fish. The correlation between absolute fecundity and length was more significant (F = 0.76TL2.8, R2 = 0.94, p < 0.05) than with weight (F = 17.683TW0.71, R2= 0.92, p < 0.05). This study provides basic information on the biology of O. niloticus in the Geray Reservoir for future fishery management tools for the conservation and utilization of this valuable freshwater fish.

Morphometric variations across fish stocks have long been acknowledged as useful for determining population structure and identifying stocks. Schizothorax progastus (McClelland) is a common, dominant fish in most cold-water rivers and is considered a good sport fish and also delicious in taste. For the people of Ladakh, this fish is a significant source of nutrition. A total of 70 specimens were collected for this study. A total of 24 morphometric and six meristic characters were studied, with 18 morphometric characters assessed as percentages of total length and four characters analyzed as percentages of head length. Standard length and fork length had the strongest correlations with total length at 0.98 and 0.99, respectively. Overall, the findings demonstrated that all morphometric features had linear correlations and exhibited a high degree of association (P < 0.05). The meristic counts examined in this study were consistent among all fish of various sizes, suggesting that body size had no effect on them. The biological information generated from this study serves as an essential guideline for future management and conservation of S. progastus, an important food source in the Ladakh, Trans Himalayan region.

This study investigates the growth pattern of 33 fish species caught by gillnets from the Egyptian Mediterranean waters off Alexandria between 2018 and 2020. This is accomplished by studying the length-weight relationship (LWR), Fulton’s condition factor (kc), the allometric condition factor (ka), and the relative weight condition factor (kn). The b-values of the length-weight relationship of the studied species varied between 2.1382 and 3.6868 according to the results. Only Dentex macrophthalmus (b = 2.1382), Etrumeus golanii (b = 2.4197), and Trichiurus lepturus (b = 3.6868) exhibited different values than the expected range of 2.5 1) is not necessarily a better condition for the fish. The study of the allometric condition factor (ka) assessed that the difference between ka and kc values influenced by the feeding intensity and the b-value. The values of the relative weight condition factor (kn) were within the range from 0.929 to 1.038, and 24 fish species reflected a good growth condition while the kn values for the remaining 9 species were less than 1.0. The obtained results add new data about specific species and provide updated data on the remaining species in the area of study. The obtained results can have useful effects on the stock assessment of fish species.

This research was conducted at Langgur City, Southeast Maluku Regency, Maluku Province, Eastern Indonesia from November 2020 to February 2021 to study biological aspects of roundscads (Decapterus spp.) which consist of species composition, sex ratio, gonad maturation level, size distribution, length-weight relationship and condition factor. Samples were collected at traditional fish market in Langgur City. Fish samples collected at the market were put into cool box and then brought to the laboratory for further examination. Fish samples were identified, separated based on species, dissected to determine their sex and gonad maturation stage and then measured. Totally, there were 290 specimen collected which consist of five species namely Decapterus kurroides, D. macarellus, D. macrosoma, D. muroadsi and D. russelli. Sex ratio between male and female for all species showed 1:1. Gonad maturation level showed that stage I and II have higher percentage than stage III and IV indicates immature fish more dominant compare to mature one. Among five species found, D. macarellus has larger size while the smaller belongs to D. muroadsi. Results of length-weight relationship analysis showed that roundscads inhabiting Southeast Maluku waters have isometric and negative allometric growth pattern with relative condition factor around 1.00.

Highlight Research • There are 26 species identified to be originated from the bay, which the highest diversity in Indonesia • Six species found in Kwandang Bay is showing trends of decreasing populations and two species vulnerable based on IUCN conservation list • Growth model and Fulton condition factor determined for 14 species indicates that they live in a good state of well beings in the bay • The models and condition factors also reflect the adequate food resources required for grouper growth which makes Kwandang Bay as a good habitat for groupers Abstract Grouper fishery has been the source of income for 3,700 fishermen in Kwandang Bay. Since 2017, grouper populations in Kwandang have been depleting due to the absence of management. This research aimed to analyze species composition, length-weight relationship, and condition factor of the groupers. Samples were collected from fishers who caught the fish using traps, speargun, and handline. Samples were identified through a method by Heemstra and Randall, while the length-weight relationship was estimated using log-linear regression and t-test. The number of specimens identified during January - December 2021 was 1,571 individuals. Research showed that those samples consisted of 26 species under eight genera. Six species found in Kwandang Bay were showing trends of decreasing populations and two species were vulnerable based on the IUCN conservation list. Length-weight relationship analysis of 14 grouper species resulted in b value ranging from 1.6359 to 3.4417 and R2 ranges from 0.7718 to 0.9858. A significant test at a 95% confident interval showed that 14 species had an isometric growth pattern. Fulton condition factors show that Kwandang Bay is an essential habitat for groupers, and the bay can support the fish growth due to the adequate food availability.

Fringescale sardinella is one of the largest fishery resources and has the highest economic value in the Savu Sea. The increasing demand for this fish makes it one of the main fishing targets, which allows overfishing to occur. Therefore, the purpose of this study was to determine the population dynamics of sardinella fringescale through growth and mortality, recruitment and exploitation rate of fringescale sardinella in Rote Island in the Savu Sea.

The current study provides the first insights into the growth and population aspects of the commercial clam Paphia textile, the most abundant bivalve species produced from the Timsah Lake (TL) and Great Bitter Lake (GBL), along the Suez Canal, Egypt. An intensive study was carried out for one year (December 2019-November 2020). A total of 14,932 random clam samples were obtained from commercial catches (before size-sorting) operated at a depth of five meters. The present results revealed a positive allometric growth pattern of shell length-weight relationship for the Paphia populations. Growth parameters derived were L∞ = 69.5 & 73.9 mm, K = 0.60 & 0.51 yr−1, to = −0.214 & −0.249, and Φ' = 3.462 & 3.445 for TL and GBL, respectively. In conclusion, the current findings revealed high mortality and exploitation levels of the venerid P. textile in TL and GBL, which highlighted the urgent need to manage this resource in its primary and exclusive areas of production along the Suez Canal.

Periophthalmus chrysospilos is an amphibious fish and considered candidates of typical aquarium fish in the Mekong Delta (MD), Vietnam. It is a species that is facing overfishing. Unfortunately, the data on its length-weight relationship (LWR), growth pattern, and condition factor are limited. The present study lasted from April 2020 to March 2021 to contribute knowledge of these data. A collection of 1,031 specimens (508 females and 523 males) was obtained from estuarine and coastal regions. The results showed that the fish total length (TL) and weight (W) were significantly different between sexes, seasons, and sites. In order to determine LWRs, weights of males and females in two sizes, seasons, four sites, and twelve months were estimated from the fish given lengths. The species displayed temporal variation in growth patterns as b values ranged from 2.87 ± 0.12 SE to 3.46 ± 0.07 SE. It generally showed positive allometric growth as b (3.22 ± 0.02 SE) was higher than the threshold of three. The fish body conditional factor was close to the well-being value of one and was not influenced by sex, but by season, site and month variations. The findings concluded that the species was well adapted to its habitat.

The mudskipper is one of the fishes that inhabit mangrove ecosystems. Its growth and distribution is influenced by food sources, tidal action, and environmental factors. The aims of the research were to analyze the growth patterns and condition factors of the mudskipper, Periophthalmus gracilis Eggert, inhabiting mangrove ecosystem rehabilitation areas in Banda Aceh and Aceh Besar, Aceh Province, Indonesia. The research period in these mangrove ecosystems was from August to October 2020. The research was conducted at three sampling stations using the purposive sampling method to determine their location. The mudskippers caught at each station were identified and body length and weight were measured. Physicochemical water parameters were measured directly at the sampling stations to determine the suitability of them for mudskipper growth and occurrence. The mean total lengths (TL) and weights (W) of the mudskipper specimens caught at stations 1, 2, and 3 were 52.0 mm and 6.2 g; 53.5 mm and 6.4 g, and 56.0 mm 6.7 g, respectively. The growth patterns of the mudskippers from the three sampling stations were negative (b < 3), and Fulton’s condition factor (K) exceeded 1. The K value at stations 1, 2, and 3 ranged from 1.28 to 3.62, 1.15 to 3.56, and 1.05 to 3.89, respectively. The relative weights (Wr) at the three stations were 103.8 ± 26.5, 104.3 ± 29.3, and 104.1 ± 28.2, respectively. Wr >100 indicated that there was sufficient food availability, low predator density, and the environment was in equilibrium. Furthermore, physicochemical water parameters at the study stations were suitable and within optimal ranges for the mudskipper. Significant differences in total length were noted among specimens from the three stations (P < 0.05); however, no significant differences in body weight were noted at them (P > 0.05).

Some biological and reproductive aspects of the Mystus bleekeri from Dekhar Haor were investi-gated. From the commercial catches, a total of 600 sample collections were performed on a month-ly basis from July 2017 to June 2018. Total length (TL, cm), body weight (W, g) and individual’s sex were identified between 216 male (36%) and 384 female (64%) fish (ratio 1.00: 1.78). Mean TL and Wofsampleswere14.85±3.38cmand27.54±15.76g,respectively.TheTLofmaleandfemaleranged from 6.9-21.3 and 7.80-24.60 cm, respectively; and W ranged from 5.3-63.3 and 6.70-76.40 g,respectively.Inlength–weightrelationshipofthisfishdepictedanegativeallometricgrowth(b=2.408) with a condition factor (Kn) of 1.04±0.11. Fish of 16.00-16.90 and 10.00-10.90 cm length groups demonstrated the highest (1.45±0.23) and lowest (0.89±0.18) Kn values, respectively which wassignificantlyvariedamongdifferentlengthgroups.MonthlystudyofgonadosomaticindexshowedtwopeaksinthemonthofMay-JuneandNovemberforbothsexes.Theresultsofthisstudy provide baseline data on some biological aspects of M. bleekeri, which would be useful in predicting the responses of M. bleekeri populations in Dekhar Haor.

The current study compared the length-weight relationships and condition factors in mono- and mixed-sex Nile tilapia (Oreochromis niloticus). The trial lasted for 91 days and included two treatments with five replications for each, all with the same stocking density. During the study period, 20 randomly selected fish individuals were measured and recorded from each cage every two weeks. The observed growth trend was allometric, with no significant difference in the mean exponential values (b), 2.696 and 2.65 for mono and mixed-sex tilapia respectively. There was a significant difference in final weight gain between monosex (171.58±7.39 g) and mixed-sex (149.09±4.14 g) tilapia. There was no significant difference in final length between monosex (19.80±0.42 cm) and mixed-sex (19.80±0.42 cm) tilapia. Moreover, the mean correlation coefficient (r2) of both groups was positive. The Fulton condition factor (K) also varies from 0.700 to 1.000 (monosex) and 1.000 to 1.010 (mixed-sex). The relative condition factor (Kn) for monosex and mixed-sex tilapia ranged from 1.96 to 2.222 and 2.092 to 2.35 respectively, indicated good aquaculture conditions. The present findings will attract fish farmers to mixed-sex tilapia culture by allowing them to lessen hormone administration and expected to boost national fish production through open water cage aquaculture.

Wallago attu is a freshwater catfish and has been classified as ‘Vulnerable’ in Red Data List of threatened species by IUCN. Length-weight relationship (LWR) of wild populations helps in understanding the pattern of fish growth that could be useful in fisheries management. The current work was carried out to the LWR and condition factor (K) of W. attu collected from five rivers of India (Ganga, Yamuna, Hooghly, Gomti and Pampa). A total of 261 fish specimens were sampled for LWR study. The value of b for the population of river Gomti (t=1.0312), Ganga (t=1.4109) and Yamuna (t=0.3365) was not significantly different from isometric growth (b=3) in Pauly’s t-test whereas the populations of Hooghly (t=10.3609) and river Pampa (t=3.4593) were significantly different (p

This study reflects the biometric characters of the endangered species Nandus nandus (Hamilton, 1822) including sex ratio, length-length relationships (LLRs), and length-weight relationships (LWRs) utilizing the sum of 14 linear variables, various meristic measurements, reproductive biology, and condition factor from the Borni Baor, a large wetland ecosystem of southwestern Bangladesh. A total of 579 specimens of N. nandus have been periodically collected from the Borni Baor throughout the year (January–December, 2019) using different traditional fishing gears. Highly significant LLRs (r2 > 0.90) values indicate that length parameters are profoundly associated with one another. In the LWR formula (W = aLb), higher exponent b values (b > 3.0) were demonstrating a positive allometric growth with a high correlation coefficient (r2 > 0.94). Moreover, monthly gonadosomatic index and dobriyal index fluctuations suggest the primary breeding season of this fish is from March to July. Data revealed the breeding time was associated strongly with the rainfall and air temperature (p

Biometric indices, i.e. i) length-weight relationships (LWRs), ii) form factor (a3.0), iii) length-frequency distributions (LFDs), and iv) condition factors (relative KR and Fulton’s KF) are considered to be very crucial in the assessment of fishery studies as they provide information on fish population growth and coastal habitat well-being. The study of biometric indices of mangrove fish has, however, received little attention. Our research investigates the LFDs, LWRs, a3.0, KR and KF of 395 individuals from nine families (Latidae, Engraulidae, Gobiidae, Mugilidae, Synbranchidae, Schilbeidae, Scatophagidae, Plotosidae, and Terapontidae). The LFDs showed that the lowest total length (TL) was 4.57 cm for Stolephorus tri, and highest TL was 56.20 for Monopterus cuchia. The LWRs showed that the b (allometric coefficient) values ranging from 2.01 (Plotosus canius) to 3.29 (Terapon jarbua), appeared as highly significant (P

Yellowfin tuna Thunnus albacares is one of the major species of tuna caught in the Fisheries Management Area (FMA) 573 of the Indian Ocean. Its production contributed to 35.83% of the total production of tuna in 2013. The study was conducted to assess the population dynamics of this species in FMA 573, based on length-frequency data collected in 2013-2017, and was analysed using FiSAT II software. The results obtained show length-weight relationship of W = 0.000052 FL2.78, negative allometric growth and growth equation of Lt = 194.25 (1-e-0.51 (t + 0.1889)). The length at first capture was estimated at 140 cm FL. Recruitment season occurs between July and September, with a peak in August. The rate of total mortality (Z) was 2.32 yr-1, including natural mortality rate (M) of 0.69 yr-1 and fishing mortality rate (F) of 1.63 yr-1. The exploitation rates of yellowfin tuna were estimated to be 0.70, indicating that it has exceeded the optimum exploitation rate (E = 0.5) and that overexploitation had occurred. There is an obvious need for consistent monitoring and surveillance of fishing fleet, type and size of fishing gear, as well as the fish size and quantity of the catch.

In this study, length-weight relationship of Umbrina cirrosa was determined in the Black Sea while giving a maximum length and weight record for this species. A total of 102 U. cirrosa were sampled by using trammel nets between 2018 and 2019 in the southern Black Sea. The mean length and the mean weight of the specimens were estimated as 32.4 cm ± 15.02 (4.8-94) and 613.1 g ± 962.69 (1.0-7051.1), respectively. One of the sampled species was measured as 94 cm in total length, weighed 7051.1 g, and was found to be 5 years old. These measurements prove this specimen to be the largest individual for the Turkish coasts. The length-weight relationship was described as W=0.009L3.0541 (R²=0.9962) with positive allometric growth for all individuals. This is the first study conducted for U. cirrosa in the Black Sea while the maximum size record is given for all Turkish coastal waters.

Areaolate grouper, Epinephelus areolatus are one of reef-associated fish species that is highly sought-after in the seafood trade. The high market demand resulted to overexploitation and population decline of the species in the wild. This paper aimed to determine the size structure of E. areolatus from the Arabian Gulf. A total of 355 samples of E. areolatus collected over the 12-month sampling period revealed high proportions of females in the sample were observed throughout the year and in size class. Males (29.3 cm, 358.44 g) are observed to be bigger and heavier than females (28.8 cm, 326.66 g). The “b” values are close to 3, which is an indication of an isometric growth. The relationship between length and weight showed significant positive correlations with p

The indigenous Schizothorax spp. in the valley of Kashmir are facing constant threats and decline in their overall population. The current aim was to analyse the comparative length-weight relationship (LWRs) and condition factor (K) of 350 specimens belonging to four Schizothorax spp. (S. plagiostomus, S. esocinus, S. labiatus and S. curvifrons) from the Vishav Stream of Kashmir Himalaya, India. The fish specimens were sampled for a period of one year from April 2018 to March 2019. The results revealed that the growth coefficient ‘b’ in all the four Schizothorax spp. was found very close to 3, indicating an isometric growth pattern. No significant difference in the ‘b’ values of four Schizothorax spp. was found when compared with the isometric value (t-test: p > 0.05). The mean value of the ‘K’ for S. plagiostomus, S. esocinus, S. curvifrons and for S. labiatus were 0.81 ± 0.07, 0.80 ± 0.08, 0.85 ± 0.08 and 0.88 ± 0.12 respectively. The mean condition factor did not vary across four species (ANOVA: p > 0.05). The present findings could serve as baseline information for the management, stock assessment and future studies of indigenous capture fishery resources of the Vishav Stream and other similar habitats.

The study was carried out in the 2012-2016 fishing seasons in the Central Black Sea coasts of Turkey. Tub gurnard (Chelidonichthys lucerna L., 1758) were examined in the commercial fishery (trawls, trammel nets and gillnets). A total of 56.104 kg tub gurnard was caught during the study period. Total length and weight of 117 tub gurnard individuals were measured. Minimum, maximum and average total lengths were calculated as 12.8 cm, 74.2 cm and 33.28±1.28 cm, respectively. The maximum length is the second maximum length for the Black Sea coasts however first maximum length for the Central Black Sea coasts of Turkey. Length-weight relationship (LWR) of tub gurnard were determined as W=0.0103L2.9876 in the study. The value of the parameter ‘b’ was found to be 2.9876 and the growth was isometric (b = 3) for tub gurnard (P > 0.05).

Alburnus carinatus Battalgil, 1941 is an endangered fish species, which has a narrow distribution range in two shallow lake basins in northwest Anatolia. The present study aimed to describe the reproductive potential of this endemic fish with the relationships between body size, weight, and fecundity. A total of 101 female A. carinatus were captured from the Manyas Lake between January and June 2019. The standard length and body weight of these samples varied between 8.1– 15.0 cm and 9.38–65.45 g, respectively. The length-weight relationship of the female A. carinatus was calculated as W = 0.020 × SL2.959 (r2 = 0.866) with isometric growth. Absolute fecundity ranged from 1512 eggs (8.1 cm SL) to 3203 eggs (10.3 cm SL) with a mean of 2281 eggs (SD = 415.2). Fecundity–length relationship was F = 5.86 × SL2.67 (r2 = 0.702) and the fecundity–length relationship was F = 476.6 + 116.5 × L (r2 = 0.688). Mean relative fecundity was calculated as 244 eggs.cm−1 (SD = 34.1) (ranged from 179.8 to 310.9 eggs.cm−1) and 148 eggs.g−1 (SD = 14.9) (ranged from 115.1 to 171.8 eggs.g−1).

This is the first paper to provide detailed information on the age and growth of Trachinotus ovatus. The size of the 244 individuals collected in the Strait of Messina ranged from 2.7 to 30.4 cm in fork length (LF) and 0.31 to 508.6 g in body mass (M). The relationship between these parameters (M - LF) was investigated and showed a good fit. Age estimation based on vertebrae and otoliths yielded similar results, suggesting a maximum age of five years. However, the precision and accuracy tests, such as percentage of agreement (PA), mean coefficient of variation (ACV) and average percent error (APE) indicated that the otolith readings (97.83% PA, 0.54% ACV and 0.38% APE) were more reliable for age estimation than vertebrae readings (82.17% PA, 5.33% ACV and 3.77% APE). The multi-model inference approach allowed us to compare different non-linear growth models. The von Bertalanffy model (L∞=29.139, k=0.496 and t0=−0.347) fitted the length-at-age data best. This species has a relatively rapid growth and an estimated longevity of five to seven years. This information could be used for management and first stock assessment studies on T. ovatus in the Mediterranean Sea.

The relationship between length and weight is non-linear. Predictive modelling using linear regression methods subjects these variables to transformation which results in models of poor predictive value. Hence, a comparative study on developing a predictive model using traditional (length-weight relationship, LWR; multiple linear regression, MLR) and artificial intelligent (artificial neural networks, ANN) methods was conducted. Specimens (n = 320) of the horse mussel Modiolus modulaides were randomly collected from October 2018 to March 2019 at the coastal area of Dumangas, Iloilo, Philippines. Shell length, shell width and shell height were used as predictor variables for total weight. A multi-layer perceptron architecture model was used and the values were determined by the ANNs model using the actual data. In addition, LWR and MLR models were generated from the same data after log-transformation. The results indicated superiority of the ANN model to predict mussel weight to traditional LWR and MLR models. The ANNs model had the highest correlation coefficient and lowest errors among the predictive models. The ANNs model generated from this study can be a good alternative to existing models and may be useful in sustainable fisheries management.

The relationships between otolith size and body length of North African catfish Clarias gariepinus (Burchell, 1822), collected from Sakaryabaşı (the main spring area of the Sakarya River) between July 2014 and November 2014, were examined. Length-weight relationship was also calculated for overall specimens. The wild fish were captured by electrofishing using SAMUS 725MP. A total of 132 individuals ranging from 13.6 to 59.0 cm in total length and from 15.9 to 1755.0 g in weight were sampled. The lagenar otolith (asteriscus) length and height, and the utricular otolith (lapillus) length and width were recorded for each fish. The relationships between otolith measurements and fish somatic growth were described by a non-linear function (power model). The t test revealed no considerable differences in these relationships between left and right otoliths. The ANCOVA test on the relationships between total length and otolith variables did not show significant differences between females and males. All relationships were highly significant and the mean percent prediction errors were less than 7%. The results showed that otolith growth reflected body growth.

In this study, changing of catch per unit effort (CPUE) and length composition of bluefish (Pomatomus saltatrix Linnaeus, 1766) caught in southern Black Sea was monitored during the period of 8 weeks in October and November 2012. A total of 2255 kg bluefishes were captured by pelagic trawl at the end of the 32 hauls. The length-weight relationships of bluefish were established as W=0.0037L3.3067 (positive allometric growth). The catch per unit effort (CPUE) and mean length were fixed as 14.43 kgh-1 and 17.5±0.03 cm, respectively. Differences between CPUE values of each weeks were found statistically significant (P

Abstract A preliminary investigation of length-weight relationship, condition factor and reproductive ecology of African pike fish, Hepsetus odoe, was conducted between June to August 2010 in Lake Eleiyele. A total of 90 samples of the fish species were caught by fishermen using gill nets. The results obtained showed that fish species had isometric growth pattern (contrary to negative allometry expected) with the growth exponent, b value of 2.64, that is not statistically different from 3 and with high statistical power of 0.866 when tested. The mean condition factor, K, was found to be 2.6, indicating that the fish species were in good condition in the study area. For reproductive biology, mean fecundity and gonadosomatic index were found to be 1349 eggs and 3.53% respectively. This study was necessary to fill the knowledge gap and provide information for management and conservation of the investigated species in the lake system. This study recommended that further research needs to be conducted because the sampling was carried out in the rainy season period and within a quarter of a year.

Length-weight relationships (LWRs) and length-length relationships (LLRs) were determined for six fish species: Alburnus alburnus, Blicca bjoerkna, Gymnocephalus cernua, Perca fluviatilis, Rutilus rutilus and Sander lucioperca caught using a Nordic multi-mesh gill net in Lake Kirkkojärvi in Southwestern Finland in August 2015. The measurements were done using a photographic method and the dataset is available on the Comprehensive R Archive Network (CRAN). The dataset was done with a scientific catch, which showed lower limits on specimen size than the ones from fisheries. The LWRs were calculated for the total length (TL) and found to be consistent with models from Finland. The length measurements were taken to the nearest 0.01 cm, which also allowed for juveniles to be represented in the model. The goodness of fit of the models is high, with the coefficients of determination above 95%. This study is the first one to estimate LWRs of fish species for this hypereutrophic lake, and is useful for fishery managers and biologists.

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. 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.

In this study growth of Atherina boyeri, collected from Süreyyabey Dam Lake, was determination by Artificial Neural Networks (ANNs) along with study of length weight relationships (LWRs). A total of 394 individuals including 32.5% female and 67.5% male specimens were studied collected during the fishing season between May 2015 and May 2016 from the local fisherman. The total length and weight of the specimens were 32–90 mm and 0.225–4.062 g respectively. The relationships were W = 0.01285708 L2.67 (R2 = 0.983) for females, W = 0.00678019 L2.95 (R2 = 0.969) for males and W = 0.00641527 L2.87 (R2 = 0.970) for pooled individuals. Mean Absolute Percentage Error (MAPE) of ANNs (0.182) for all specimens was lower than MAPE value of LWR (1.763). The results of study show that ANNs are superior tool to LWRs for fishes of Süreyyabey Dam Lake.

Allometry, condition index and sex ratio in freshwater mussel Lamellidens corrianus (Lea, 1834) were studied from the freshwater lake at Rajshahi, Northwest Bangladesh during the summer 2013. The collected mussel specimens ranged from 3.69 cm to 9.98 cm in length, and 4.82 g to 80.67 g in weight. The study was focused on the relationships between length-height and length-weights (length-total weight, length-tissue wet weight, length-shell wet weight, length-tissue dry weight and length-shell dry weight), which were found not to be significantly different between male and female (P

Length-weight relationship study of narrow-barred spanish mackerel (Scomberomorus commerson) from Semarang waters was commenced in October-November 2014. The result showed that the fish growth at both the months of October and November 2014 was a negative allometric growth. There was uncertainty to answer the low value for b component during November although at this month was a peak of the fish catching at Java Sea. Due to small fish landed, it indicated that narrow-barred Spanish mackerel of Semarang waters were not proper to be caught. Studi hubungan panjang-berat ikan tenggiri (Scomberomorus commerson) dari perairan Semarang sudah dilakukan selama bulan Oktober dan November 2014. Hasil penelitian menunjukkan bahwa pertumbuhan ikan tenggiri selama bulan Oktober maupun November 2014 adalah bersifat allometrik negative. Tidak diketahui dengan pasti penyebab kecilnya nilai b terutama pada bulan November, meskipun pada periode tersebut merupakan salah satu puncak musim penangkapan ikan tenggiri di Laut Jawa. Kecilnya ukuran ikan yang didaratkan, menunjukkan bahwa ukuran ikan tenggiri di perairan Semarang belum layak tangkap.

An attempt was made to study dynamics of length-weight relationship (LWR), relative condition factor (Kn) and gonado-somatic index (GSI) of Labeo calbasu from the wetlands of South 24 Parganas district of West Bengal, India. A total of 275 fish specimens (130 to 430 mm) were examined over nine months from December 2006 to August 2007. Specimens were categorized into two groups based on the size at first maturity of 260 mm. The LWR was recorded W = 0.007269 L3.181 for Group A (

Age and the growth of the black seabream Spondyliosoma cantharus (Linnaeus, 1758) from the Gulf of Tunis were investigated using scales and otoliths. The length-weight relationship showed that the growth rates were isometric for females whereas males and the whole sample present a positive allometry. The monthly evolution in marginal increment data of scales and otoliths revealed that only one annulus is formed per year in April. Fish length and radii of the scales or otoliths were closely correlated. The von Bertalanffy growth equation was fitted on mean back-calculated length-at-age data, resulting in the parameter values L∞=35.4 cm, k=0.15 y–1 and t0=–0.19 y for scales and L∞=38.6 cm, k=0.10 y–1 and t0=–0.14 y for otoliths. Parameters estimated from scale and otoliths were significantly similar. However, taking into consideration the lower standard deviations of means for estimates based on otolith readings and the higher variance explained by the regression line fitted to otoliths, the latter seem to be more appropriate for ageing S. cantharus. The maximum age of the black seabream of the Gulf of Tunis is 10 years. Large discrepancies in growth parameters between geographic areas are the result of different growth patterns.

TThe length-weight relationships (LWRs) were determined for five freshwater fish species collected from Liangzi Lake, the Xi River and Longxi River in China, including Megalobrama amblycephala, Megalobrama skolkovii, Megalobrama pellegrini and Megalobrama terminalis belonging to the genus Megalobrama, as well as white Amur bream (Parabramis pekinensis) of the genus Parabramis. Three of these five species had no previous LWR estimates in the FishBase. The LWRs of hybrids from Megalobrama amblycephala ♀ × Parabramis pekinensis ♂ and Megalobrama amblycephala ♀ × Megalobrama terminalis ♂ were also reported for the first time.

For the first time, Oriental river prawn Mcrobrachium nipponense were investigated in three international lagoons the (Aalgol, Ajigol and Almagol) in ٢٠٩-٢١٠sampling take place monthly using collapsible traps (Funnel Trap). In this study the max ٢٣١٠male and ١٧٧٩ female specimens and min ٥٩٩ male and ٦٦٧ female specimens were caught, and, ٦٦٧ in the Alagol and Ajigol respectively. In the three lagoons, females were smaller than males. Comparing the average mean length males and females showed significant difference among the Ajigol with the other lagoons and the Alagol with the other lagoons respectively.

The length-weight relationships and the regressions between otolith size (length and width) and fish length of some mesopelagic and bathypelagic fishes living in the central Mediterranean Sea were provided. Images and morphological description of otoliths (sagittae) from 16 species belonging to the families of Gonostomatidae (1), Microstomatidae (2), Myctophidae (8), Phosichthyidae (2), Sternoptychidae (2) and Stomiidae (1) were given. The length-weight relationship showed an isometric growth in 13 species. No differences between right and left otolith sizes were detected by t-test, so a single linear regression was plotted against standard length (SL) for otolith length (OL) and otolith width (OW). Data fitted well to the regression model for both OL and OW to SL, for each species (R2 > 0.8). These relationships offer a helpful tool in feeding studies and also provide support to palaeontologists in their research on fish fossils.

This paper presents the results of some morphometric and meristic parameters of sardine, Sardina pilchardus (Walbaum, 1792) from coastal (Virsko more) and open waters (Dugi Otok) of the Zadar area, during the period from March 2004 to February 2005. The total length of all analyzed specimens ranged from 13.0 to 19.0 cm and weights ranged between 16.72 g and 51.45 g, respectively. Body length analyses indicated greater values for sardine females (N=541) than males (N=668) in all observed lengths (LT, LF, LS, LA, LH, OK, LP and BD), except for the eye diameter (ED), where both sexes had equal average value. The length–weight relationship indicated negative allometric growth (b=2.5538, a=0.0261). In length–length relationships, statistical significance occurred in the following relationships: eye diameter in head length (2.78%) and head length in total length (9.01%). For vertebrae analyses, two groups were compared according to their length: the first one obtained specimens smaller than 16.0 cm in total length (LT), whereas samples longer than 16.0 cm belonged to the second group. The number of vertebrae in both groups ranged between 48 and 52 with the most abundant vertebrae class of 50 vertebrae (37.7 %), whereas a minimal number of sardines (4.9 %) had 48 vertebras. A statistically significant difference between the two analyzed groups was not found (t=0.86). The number of rays (RD) in the dorsal fin ranged from 17 to 19 and the average value was 18.11 ± 0.51.

Se usa un método alternativo para estimar la talla de madurez del jurel, que considera el consumo relativo de oxígeno en función del peso corporal y la constancia que ocurre en peces teleósteos entre el consumo relativo de oxígeno en la madurez y el tamaño asintótico. La varianza de la estimación se evaluó por el método de Monte Cario, considerando la incertidumbre en los parámetros de la relación longitud-peso y del consumo relativo de oxígeno. La talla de madurez fue estimada en 25,5 cm de longitud horquilla (17,7-31,3 cm), y fue similar a las estimaciones disponibles obtenidas mediante análisis histológico de hembras maduras. El método se aplicó a otras especies para demostrar su utilidad en la estimación de la talla de madurez sexual en peces.An alternative method was used to estimate size at maturity for jack mackerel. This method considers relative oxygen consumption as a function of body weight and the consistency of relative oxygen consumption at the size at first maturity and at the asymptotic size in teleosts. Variance in the estimation was evaluated with the Monte Cario method and considering the uncertainty in the parameters of the length-weight relationship and relative oxygen consumption. Size at first maturity was estimated to be 25.5 cm fork length (17.7-31.3 cm), which was similar to other estimates made using histological analyses of mature females. The method was applied to other species with the objective of demonstrating its usefulness for estimating size at first maturity in fishes.

The sexual activity of Diplodus sargus sargus in the Gulf of Tunis takes place from January to May. Spawning occurs in spring (March to May), as the water temperature rises from 15 to 18°C, just after the winter minimum. The spawning period increases as the latitude decreases. The overall male to female ratio was statistically different from unity. Size at sexual maturity (TL50) was 21 cm (4 years old). The length-weight relationship for all individuals was described by the following parameters: a = 0.015 and b = 3.051. D. s. sargus from the Gulf of Tunis is a rudimentary hermaphrodite with partial protandry.

This paper considers the length–weight relationship of six out of eight most commonly found fish species inhabiting the Vardar River biotope, the largest riverine system in the central part of the Balkan Peninsula: Alburnoides bipunctatus (Bloch, 1782); Alburnus alburnus (Linnaeus, 1758), Barbus macedonicus Karaman, 1928; Barbus peloponnesius Valenciennes, 1842; Chondrostoma vardarense Karaman, 1928 and Leuciscus cephalus (Linnaeus, 1758), two of which are endemic. Satisfactory results for all the length groups have been determined only for B. peloponnesius whereas for the other fish species exceptions were noted for some of the length classes. The rational behind this can be sought in two reasons: insufficient number of individuals in a concrete length class or sexual maturation causing the prespawning or postspawning influence on the change of the weight of the fish.

In this study we present the longest time series available concerning various biological parameters of sardine in Greek waters. Biweekly samples were collected within a single day in clusters from random collections of the total landed catch derived from different vessels operating in the Northwest Aegean Sea, between July 1996 and June 2000. Total length (TL) was measured for 51.246 individuals. In addition, for a sub-sample of 50 individuals per sampling period, gross body weight and gonad weight were also measured to the nearest 0.1 and 0.01 g respectively. The analysis of the biweekly length-frequencies showed that the dominant length classes ranged between 130 and 160 mm TL. The mean biweekly TL decreased significantly (r=-0.525, P

Glossogobius giuris were collected during March to September 2013 from the Payra river to estimate the length-weight relationship with relative condition factor (Kn), fecundity, gonadosomatic index (GSI) and relation between fecundity and other parameters. The length-weight relationship was found to be Log W= 2.667 Log TL – 1.805 in male and Log W = 2.931 Log TL – 2.040 in female. The mean Kn were found to be 1.02±0.155 for male and 0.97±0.276 for female which indicates satisfactory condition of the fish population. The mean relative fecundity was ranged from 88495 to 264104 with a mean value of 171581±17855, having a average total length of 21.21±0.44 cm, body weight 70.22±4.62 g and gonad weight 2.74±0.31 g. The relationships among the fecundity, the total length, body weight, gonad weight were found to be linear and positively correlated. The mean GSI value was 3.42±0.33 and the highest GSI value was recorded 9.34±0.71 in the month of September. This study will help to introduce this species in sustainable aquaculture through proper management and for the development of induced breeding technique.

Fishery dependent data from various commercial and recreational sampling programs form the basis for characterizing the fishery for dolphinfish (Coryphaenus hippurus) in the waters of the Gulf of Mexico and off the southeastern U.S. coast. Three states in the region have implemented size and bag limits for dolphinfishes, but there are no federal regulations in place at this time. Commercial landings were relatively small in comparison to recreational landings from 1984 through 1996. In 1995 however, commercial landings in the Atlantic Ocean of the southeastern U.S. were almost twice the weight of the previous years. The average weight per fish was calculated for each water body and fishing sector and there appear to have been significant increases in the average weight of fish landed both in the commercial and recreational sectors in the Atlantic and the Gulf of Mexico. Catch per unit of effort is measured as numbers of fish caught per angler per hour in the recreational fishery and has been variable since the early 1980s. In light of increasing landings and average weights of fish landed since the 1980s, the sustainability of this fishery must be fully evaluated.