Allometric Growth Pattern Research Articles

Life history of an evolutionary distinct aquatic caecilian amphibian (genus Potomotyphlus) in eastern Amazonia, Brazil

Abstract Basic ecological data for caecilians are relatively lacking. This study presents the first comprehensive ecological investigation of the Amazonian aquatic caecilian Potomotyphlus kaupii, utilizing a large sample size. We collected population data over a 14-month period, and also used data of museum specimens, both from Belém, State of Pará, Brazil. Our analysis focused on sex ratio, sexual size dimorphism (SSD), female fecundity, and ecological observations. No significant differences in adult sex ratio were found. SSD was found in some characters such as circumference at midbody and body mass with females being larger than males, while males had a wider and longer cloacal disc. We provide the first determination of the approximate size at which males diverge from females in the terminal portion of the body, demonstrating an allometric growth pattern of the cloacal region. Female size showed a positive correlation with the number of ovarian eggs, indicating an important reproductive strategy. Furthermore, a novel behaviour in P. kaupii was documented. We expand the understanding of Gymnophiona biology, in particular of a fully aquatic species, and provide support for future ecological and conservation research on caecilians.

The Growth Pattern and Condition Factors of Swanggi (Pracanthus tayenus Richardson, 1846) Landed at Coastal Fishing Port of Lempasing

Lempasing Coastal Fishery Port is one of the fishing ports in Lampung Province with one of the catches is Swanggi (Priacanthus tayenus) or local people call it king fish gantang. The purpose of this study was to determine the growth pattern and condition factors of Swanggi (Priacanthus tayenus) landed at the Lempasing Coastal Fishery Port as an effort to manage sustainable fishery resources. This research was conducted in May-August 2023. The method used in this research is the survey method. Sampling was done 8 times with an intensity of 2 weeks. Swanggi samples used are the result of fishermen's catch at PPP Lempasing. The results showed that male and female Swanggi had a negative allometric growth pattern. The condition factor value of male Swanggi in May-August 2023 is 1.0437; 0.9414; 1.01; 1.0057, respectively, while the female Swanggi obtained the average condition factor value is 1.4502; 0.9937; 0.9937; 1.0057.

Length-Weight Relationship and Condition Factors of Sea Cucumber on Mare and Moti Islands Conservation Areas in North Maluku

This work aimed at determining the growth patterns and condition factors of three sea cucumber species, namely Holothuria atra, Bohadschia marmomata, and B. vitiensis in seagrass beds of Mare and Moti Islands. Samples were collected in March 2023 using a roaming survey method in a block area with an area of 5000 m2. As amount of 54 sea cucumbers were analysed from Mare Island and 58 individuals from Moti Island. The results of this study indicate that the correlation (r) length-weight relationship for the three sea cucumber species is stronger (r > 0.6) on Moti Island than Mare Island. H. atra and B. marmorata have a negative allometric growth pattern, while B. vitiensis has a positive allometric growth pattern on both islands. The Fulton condition factors for the sea cucumbers assessed on Mare Island were recorded for H. atra of 2.84 ± 2.01, B. marmorata of 3.13 ± 2.47 and B. vitiensis of 9.24 ± 5.73. Meanwhile, at Moti Island were found for H. atra of 12.49 ± 11.66, B. marmorata of 9.58 ± 7.38, and B. vitiensis of 8.87 ± 3.68. This is indicated that all sea cucumber species are in good physical condition. Meanwhile, the relative weight condition factor (Wr) of the three species of sea cucumbers on both islands were in the range above 100, which indicated a food surplus in their habitat. The results of this research can be important as the preliminary data in terms of sustainable management of sea cucumber stocks in North Maluku.

Carapace Length-weight, Carapace Width-weight Relationships, Condition Factor and Sex Ratio of Freshwater Crab Sartoriana spinigera (Wood-Mason, 1971) from the River Burhi Gandak, North Bihar, India

Background: The Burhi Gandak river origins in the Chautarwa Chaur region near Bisambharpur in the West Champaran district of Bihar and flows through the East Champaran, Muzafarpur, Samastipur and Begusarai districts. It falls into the river Ganga near Khagaria district. Its coordinates are 25°51'40''N latitudes and 85°48'36''E longitudes. The total area of catchment is 12500 sq. km in size overall, of which 9601 sq. km are in Bihar and the rest in Nepal. The study will be helpful for stock estimation, developing conservation and choosing appropriate species for aquaculture. The present data can be used to develop conservation plans while providing biological data needed for an effective management of this fishery. Methods: The carapace length-weight, carapace width-weight relationship, condition factor and sex ratio of freshwater crab Sartoriana spinigera (n=663) collected from River Burhi Gandak, North Bihar, between July 2020 to June 2021. In the present investigation, freshwater crabs were collected from different types of techniques, including hand-picking, digging, setting traps and taking them from their nest. Result: Total of 663 specimens of Sartoriana spinigera (Wood-Mason, 1971) of both sexes (male and female) were collected in which 363 female and 300 male. The carapace length-weight of Sartoriana spinigera females were calculated as W = 0.9122.521 with R2 = 0.875, male W = 0.43102.505 with R2 = 0.853 and length-weight of combined sex (male and female) were calculated as W = 0.6612.701 with R2 = 0.954. The carapace width-weight of female were calculated as W = 0.5542.331 with R2 = 0.831, male W = 0.7912.421 with R2 = 0.802 and carapace length-weight of combined sex (male and female) were calculated as W = 0.18122.601 with R2 = 0.900. From this study showed it could be stated that crabs have allometric growth pattern. The Fulton’s condition factor (Kn) value were calculated as 1.10 and sex ratio calculated was 1:1.49. This paper provides information.

Allometric Growth Pattern and Hunger Tolerance of Hemibarbus maculatus Bleeker Larvae.

To clarify the allometric growth pattern and hunger tolerance of Hemibarbus maculatus Bleeker larvae, the morphological lengths of their functional organs were measured continuously and their primary feeding rates under a state of starvation were studied. A control group and starvation group were set up for this study, and 10 larvae were sampled from each group every day in order to study their allometric growth pattern and starvation tolerance. The results indicated that the Hemibarbus maculatus larvae opened their mouths for feeding at 4 days after hatching, and that the yolk sac disappeared completely at 11 days after hatching. The Hemibarbus maculatus larvae preferentially developed their heads, fins, and eyes, related to the functions of feeding, balancing, and swimming, in order to cope with complex environments. The growth inflection points for the head length, pectoral fin length, dorsal fin length, eye diameter, eye spacing, snout length, and body height were characterized by total lengths of 10.93 mm, 11.67 mm, 11.67 mm, 13.17 mm, 16.53 mm, 15.13 mm, and 15.13 mm, respectively. Prior to and following the inflection point, positive allometric growth was observed in all organs. After the inflection point, the dorsal fin continued to maintain positive allometric growth, while the others changed to isometric allometric growth. A growth inflection point was not observed for trunk length or the lengths of the tail and anal fins. The trunk length always maintained negative allometry, while the tail and anal fin lengths were reversed. The growth inflection point of the tail length was at a total length of 13.68 mm. Before and after the growth inflection point, negative and isometric allometric growths were observed, respectively. According to the relationship between the total length and number of days after hatching, the growth inflection point of the Hemibarbus maculatus larvae was concentrated at TL = 10.93-16.53 mm, which was observed 14-20 days after hatching. The point of no return for the Hemibarbus maculatus larvae was 12-13 days after hatching, and the ratio of days after hatching in the mixed trophic period to the endotrophic period was 1.75, indicating that the larvae had strong hunger tolerance. Therefore, when considering a water temperature of 22.66 ± 1.56 °C, 4-5 days after hatching is the best time to cultivate in the pond, and it should not be carried out later than 12 days after hatching.

THE LENGTH-WEIGHT RELATIONSHIP OF Butis sp. IN THE TAMBUN RIVER, TOLITOLI DISTRICT, CENTRAL SULAWESI

Butis sp. is a type of fish that possesses physical characteristics such as small scales and a yellowish belly. Information regarding the existence and growth of this type of fish is still limited to the Tambun River, Tolitoli Regency. Analyzing the length and weight of the fish is one of the methods used to determine the biological conditions and fish stocks, there by facilitating the management of biodiversity sustainability. The aim of this study was to determine the relationship between the length and weight of Butis sp. in order to understand fish growth patterns. This research was carried out for 2 months in Sungai Tambun, Tolitoli Regency, Central Sulawesi Province. The location for collecting sample were divided into 3 stations. The test parameters observed were the relationship between length and weight and habitat conditions. The research results of Butis sp. in Sungai Tambun, Tolitoli Regency showed a positive allometric growth pattern (b= 3,25). The water quality in the Tambun River still supports the growth of Butis sp. (temperature 25-28oC, pH 5,5-8,5).Keywords : Biodiversity, fish biology, growth, positive allometrics

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

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

Osmoregulation pattern, condition factor, and gonadal maturity level of sea urchins in the various ecosystems of Panjang Island, Jepara, Indonesia

Abstract. Suryanti S, Anggoro S, A’in C, Widyorini N. 2024. Osmoregulation pattern, condition factor, and gonadal maturity level of sea urchins in the various ecosystems of Panjang Island, Jepara, Indonesia. Biodiversitas 25: 502-509. Panjang Island has a diversity of ecosystems. It is also famous for its abundance of echinoids, especially sea urchins. Currently, research on sea urchins in Panjang Island is mostly limited to studies on the abundance and maturity of gonads. This study investigates the osmoregulation patterns, condition factors, and maturity indices of sea urchin gonads in different ecosystems that are sea urchin habitats on Panjang Island, Jepara, Indonesia. Sampling is done randomly, while the research method is a case study. The results showed that there are 2 species of sea urchins found on Panjang Island, namely Diadema setosum Leske, 1778 and Echinothrix calamaris Pallas, 1774. Analysis of osmoregulation patterns showed that sea urchins at station 1 were hyperconformers, while sea urchins at stations 2 and 3 were hypo-conformers. Sea urchins at 3 stations had a positive allometric growth pattern (b>3) and a high condition factor (K>1). The average Gonadosomatic Index (GI) calculation result was 8.72%, while the type of ecosystem of the research stations influenced the color and texture of different gonads. Sea urchins are in immature, mature, and spawning stages, so the sea urchins on Panjang Island were partially spawned.

Kelimpahan Dan Pola Pertumbuhan Kerang Bulu (Anadara antiquata) di Perairan Gunung Riting Kabupaten Belitung

Gunung Riting waters are located in Belitung Regency which has high water biota resource potential. One biota that has a high economic value is the feather shell (Anadara antiquata). Feather shells generally live in muddy waters in shallow waters with a high turbidity levels and are one of the important commodities that are very potentially developed. The purpose of this study was to find out the abundance, growth patterns and water quality in the waters of gunung which is the habitat of feather shells. The study was conducted from December 2019 to January 2020 at 3 sampling stations, sampling using the transect method. The results of the study obtained that the highest number of feather shells found in the waters of gunung riting obtained at Station 2 is 506 feather shells with an abundance of 33.73 individuals/m2, the pattern of growth of feather shells in the waters of gunung riting has an negative allometric growth pattern where long growth is more dominant than weight growth and the water quality obtained is able to support the growth and abundance of feather shells in the waters of gunung riting.

Early development and allometric growth patterns of Larimichthys crocea (Richardson, 1846)

In order to enhance the hatching rate of eggs and the survival rate of juveniles of Larimichthys crocea (Naozhou population), and provide a theoretical basis for artificial induction and juvenile breeding, this study observed and analyzed the chronological characteristics of embryonic development and larvae(juvenile) development of L. crocea. Morphological parameters were measured, and regression equations for growth characteristics during the juvenile stage were deduced, followed by an analysis of allometric growth. The results revealed that the fertilized eggs of L. crocea were buoyant, with a diameter of (1.27 ± 0.09) mm, possessing a tough eggshell. The eggs were transparent and spherical, typically containing a single oil droplet without stickiness. Under the conditions of a hatching temperature of (24 ± 1)°C, salinity of (34 ± 1)‰, and pH of (7.8 ± 0.5), embryonic development encompassed 7 stages and 21 periods, requiring 26 h and 1 min. The total length of newly hatched larvae was (2.782 ± 0.349) mm, showing transparency. They progressed through the larval stage (0–18 DPH) and juvenile stage (19–25 DPH), and by the 25th day, all fins were fully developed. This study recorded the formation time of various organs in L. crocea, and conducted in-depth research on the biological characteristics. The results of allometric growth indicated that a higher allometric growth coefficient (before reaching 6 mm TL) is likely the combined result of various factors in the aquaculture environment, rather than a single factor. Further research should be conducted to investigate which aquaculture environmental factors have the greatest impact on the early development of L. crocea and their regulatory mechanisms. This can provide a theoretical basis for improving the survival rate of its fry.

Ontogenetic shifts in body form in the bull shark Carcharhinus leucas.

Recent studies have uncovered mosaic patterns of allometric and isometric growth underlying ontogenetic shifts in the body form of elasmobranch species (shark and rays). It is thought that shifts in trophic and spatial ecology through ontogeny drive these morphological changes; however, additional hypotheses relating to developmental constraints have also been posed. The bull shark (Carcharhinus leucas) is a large-bodied coastal shark that exhibits strong ontogenetic shifts in trophic and spatial ecology. In this study, we utilise a large data set covering a large number of morphological structures to reveal ontogenetic shifts in the body form of C. leucas, stratifying analyses by sex and size classes to provide fine-scale, more ecomorphologically relevant results. Our results indicate shifts in functional demands across the body through ontogeny, driven by selective pressures relating to trophic and spatial ecology driving the evolution of allometry. We also find significant differences in scaling trends between life stages, and between the sexes, highlighting the importance of utilising large, diverse datasets that can be stratified in this way to improve our understanding of elasmobranch morphological evolution. Ultimately, we discuss the implications of these results for existing ecomorphological hypotheses regarding the evolution of specific morphological structures, and pose novel hypotheses where relevant.

Age, growth, reproduction and mortality of Xenocypris argentea (Günther,1868) in the lower reaches of the Tangwang River, China.

To investigate various population biological parameters of Xenocypris argentea in the lower reaches of the Tangwang River (China), a comprehensive study was conducted for the first time. A total of 1,003 samples were collected from April to November 2022. The collected samples revealed that female X. argentea had total lengths ranging from 12.4 cm to 25.7 cm (weighing 15.86 g to 159.55 g), and male X. argentea had total lengths ranging from 10.8 cm to 23.9 cm (weighing 9.27 g to 121.06 g). The age of the samples was determined using otolith analysis, indicating that the ages ranged from 1 to 5 years old in both females and males. The length-weight relationships were further analyzed, uncovering the allometric growth index (b) was 3.1296 for females, indicating a positive allometric growth pattern. Differently, males exhibited a b value of 3.0274, suggesting an isometric growth pattern. Furthermore, the von Bertalanffy growth formula provided insights into the growth characteristics of X. argentea, revealing an asymptotic total length (L∞) of 36.096 cm and a growth coefficient (K) of 0.121. The analysis of the gonadal somatic index (GSI) and ovarian development period indicated that the spawning period occurred from April to July, with peak spawning in June. The study also explored fecundity-related traits, finding that individual absolute fecundity (FA) ranged from 11,364 eggs to 56,377 eggs, while eviscerated body weight relative fecundity (FW) ranged from 209 eggs/g to 823 eggs/g. The exploitation rate (E) for X. argentea was calculated as 0.574, suggesting that the population of X. argentea has been overexploited. By revealing previously unknown data on the key life history traits of X. argentea, this study has provided valuable insights that are crucial for the development of conservation strategies and policies.

Length-weight relationship, condition factor, and reproductive aspects of Lutke's halfbeak Hemiramphus lutkei (Valenciennes, 1847) from Seram Sea, Maluku, Indonesia

Abstract. Talakua M, Suadi, Djumanto, Setyobudi E. 2023. Length-weight relationship, condition factor, and reproductive aspects of Lutke's halfbeak Hemiramphus lutkei (Valenciennes, 1847) from Seram Sea, Maluku, Indonesia. Biodiversitas 24: 6574-6583. Lutke's halfbeak is one of the Seram Sea's most commercially important fish species, providing food resources and community livelihood for an extended duration. Data and information on fish biology are important for responsible fisheries management. This research aimed to determine Luke's halfbeak's length-weight relationship, condition factor, and reproductive aspects at Seram Sea, Maluku. Fish samples were collected monthly for seven months, from August 2021 to February 2022. Each sample was measured for its length and weight and then dissected for sex and gonad maturity stage determination. The data was analyzed to determine the length-weight relationship, the condition factor, the distribution of gonadal maturity stage, and fecundity. Hemiramphus lutkei (Valenciennes, 1847), originating from the Seram Sea, indicates a negative allometric growth pattern. The average relative condition factor (Kn) of H. lutkei in the Maluku Seram Sea was around 1 and did not show a significant difference between males and females. The condition factor varied during the observation period, ranging from 0.92 to 1.09. The fish are mostly (80%) in good or very good condition. H. lutkei has a high potential fecundity; spawning was predicted throughout the year, with individual fecundity ranging from 263 to 1893 eggs. Luke's halfbeak populations in the Seram Sea could be exploited sustainably; however, this should be conducted with proper management.

GROWTH PATTERN OF ATYA GABONENSIS AND MACROBRACHIUM MACROBRACHION FROM LOWER RIVER BENUE, MAKURDI–NIGERIA

Data on growth parameters of Atya gabonensis and Macrobrachium macrobrachion were collected over a period of 6 months from August 2021 to January 2022. A total of one hundred and seventy (170) specimens of M. macrobrachion and two hundred and forty (240) specimens of A.gabonensis were hand-picked under rocks and crevices under the water by the help of fishermen who dived in, while M. macrobrachium were trapped using unbaited local non-return basket trap made of bamboo and a non-return set trap. The collected samples were transported live to the fisheries laboratory, University of Agriculture, Makurdi in ice box containing water for further analysis using independent sample t-test to determine the mean values.The result of the length weight relationship revealed that apart from fig 4. Fig. 1, 2, 3 and 5 showed a strong correlation between the length and weight of the two (2) species (R2=0.8615), (R² = 0.8812), (R2=0.8761), (R2=0.5523), (R2=0.7482) and the b values were less than three (3) which shows a negative allometric growth.Apart from gut length ,gut weight and carapace length in table 2 the result for seasonal variation in some morphometric parameters in Atya gabonensis and Macrobrachun macrobrachion differed significantly in both seasons (wet and dry). The result for the morphormetric parameters for table 3 and 4 all showed significant differences. It was concluded that this species exhibit an allometric growth pattern. I therefor recommend more work be done in other areas of the biology of these prawns inorder to provide accurate informations for their domestication.

Allometric Growth Patterns of Leiocassis longirostris Larvae and their Ecological Significance

Allometric Growth Patterns of Leiocassis longirostris Larvae and their Ecological Significance

Quantitative Assessment of Ailia coila (Hamilton, 1822) Fish Population in Kaptai Lake: A Length‐Based Approach

ABSTRACTThe Ailia coila, a small indigenous freshwater fish species in Kaptai Lake, plays a crucial role in providing employment, food, and financial security for the local people. With a high market demand, the average production of this species over the last 5 years reached about 112.27 metric tons. However, there has been a notable decline in Ailia coila fish production in Kaptai Lake in recent years. Therefore, to understand the current stock status of this species, this study employed a length‐based stock assessment method the “length‐based spawning potential ratio (LB‐SPR)”. Between August 2022 and March 2023, a total of 1219 individuals were collected through fortnightly sampling from two fish landing centers (BFDC fishery ghat and Kaptai boat ghat) and two local markets (Banarupa Bazar and Reserve Bazar). The maximum length of Ailia coila was recorded at 15.7 cm in total length, with an average length of 11.1 (±4) cm. The length‐weight relationship was estimated as W = 0.01084 L2.599 (R2 = 0.75). The value of shape parameter ‘b’ is smaller than three which indicate a negative allometric growth pattern. The estimated asymptotic length (L∞) and length at first maturity (L50%) were found to be 16.84 and 10.54 cm, respectively. The LB‐SPR revealed that the fishery is currently experiencing overfishing, with the spawning biomass (SPR = 32%) below the target reference point. The mean estimate of fishing mortality relative to natural mortality (F/M) was 3.07, more than three times the threshold F/M = 1, indicating extreme fishing mortality in this fishery. The estimated length at first capture (SL50%) was significantly higher than the length at first maturity (L50%), suggesting that the fishing is predominantly targeting mature fishes. To enhance the spawning biomass and ensure the sustainability of the fishery, it is imperative to reduce the current fishing pressure and implement appropriate management measures.

Length-Weight Relationship of Fishes in Some Rivers of Morang, Nepal

The length-weight relationship is a crucial aspect of fishery assessments, providing valuable biological information. The length-weight relationship is expressed by the equation W = aLb, where W represents the total weight of the fish and L denotes the standard length. The LWR equation was transformed into a linear form using logarithmic transformation: LogW = a + bLogL. The biometric data obtained from this study includes information on species, sample numbers (N), standard length range, total weight range, and the length-weight relationship constants (a and b) for each species. In this study, we estimated the length-weight relationship of 16 freshwater fish species from some rivers of Morang district, Eastern Nepal. A total of 1,600 fish specimens, representing 16 different species from 5 families were studied from September 2022 to February 2023. The fishes were captured from the river and preserved in 20% formalin for subsequent biometric measurements in the laboratory. Biometric measurements were taken as follows: for each fish, length measurements were listed as standard length or fork length (SL in cm) from mouth to where the caudal fin is lobate. Length measurements were taken with a regular ruler validated against a Vernier Calliper, with an accuracy of 0.1 cm. Weight measurements were obtained using an electronic digital balance with a precision of 0.01 g. While listing weight, a fish consistency was maintained concerning the degree of wetness of the body to ensure accuracy. Among the species listed in the Morang district, Puntius terio has the smallest range of standard length (2.7 cm - 7.4 cm) and total weight (1.07 g - 7.06 g) while Garra gotyla gotyla has the largest range of standard length (4.3 cm - 18.6 cm) and total weight (4.5 g - 15.6 g). These variations indicate the natural size differences among the species. The analysis of the length-weight relationships revealed that all the studied fish species exhibited a negative allometric growth pattern. This means that as the length of the fish increases, its weight increases at a slower rate. The findings of this study contribute to our understanding of the growth patterns of freshwater fish species in the study area.

Length-Weight Relationships and Condition Factors of Kawakawa Euthynnus affinis and Longtail Tuna Thunnus tonggol from Sarawak, Malaysia

Length-weight relationships (LWR) and condition factors (K) were determined for two neritic tuna species Euthynnus affinis and Thunnus tonggol, caught in Sarawak waters. Specimens were collected from five locations around Sarawak between 2016-2019. The r2 value of the LWR for each species re both close to 1 (>0.9), indicating a highly significant relationship attributed to the length and weight of the fish species . The K values are 1.94 and 1.97, and the values of b in the LW equation are 2.53 and 2.59 for E. affinis and T. tonggol, respectively. The b<3 values indicates negative allometric growth patterns, where the growth rate of body length is faster than the weight gain. These values fall within the published range of 2.50 to 3.50 for neritic tuna species in the region. The results of this study provide the basic life history parameters and the general condition of the two species, E. affinis and T. tonggol, useful for our tuna fish stock assessment efforts in Sarawak waters.

Biological parameters and spawning potential ratio of Longtail Tuna Thunnus tonggol landed in Kranji fishing port, Lamongan District, Indonesia

Abstract. Harlyan LI, Rahman MA, Rihmi MK, Abdillah SFA. 2023. Biological parameters and spawning potential ratio of Longtail Tuna Thunnus tonggol landed in Kranji fishing port, Lamongan District, Indonesia. Biodiversitas 24: 6527-6535. Longtail Tuna (Thunnus tonggol), one of the small-pelagic tropical fisheries in the Fisheries Management Area (FMA-712), is important in supporting global food security. Therefore, to ensure its sustainability, this fishery is applying for fishery certification to be an ecolabel fishery by the Marine Stewardship Council (MSC). However, limited information about Longtail Tuna's biological parameters and stock status in this management area will lead to failure in certification completion. This study aims to provide biological parameters and stock status of Longtail Tuna landed in the Kranji fishing port, Lamongan, Indonesia. Length, weight, and gonad weight of female Longtail Tuna individuals which landed in the Kranji fishing port were conducted from January to April 2023. Several analyses were carried out to figure out the biological parameters of Longtail Tuna, such as length-weight relationship, length at first maturity ( ) and length at first capture ( ) estimation. Length-Based Spawning Potential Ratio (LB-SPR) analysis was conducted to estimate fish exploitation. Results showed that the Longtail Tuna landing in the Kranji fishing port exhibited a negative allometric growth pattern with the length-weight relationship model W = 0.0433 FL2.7608. A comparison between (43.9+0.11cm) and (43.6+0.04cm) indicated that most female Longtail Tuna landed in the Kranji fishing port are mature (60% of the total samples). The LB-SPR analysis showed moderate exploitation status (SPR = 34%). Fishing activities are still manageable in this situation by focusing on stock sustainability. An overlapping fishing ground occurs in the Kranji water, showing the domination of two species landed in the Kranji fishing port, Longtail Tuna and Eastern Little Tuna (Euthynnus affinis). Therefore, Longtail Tuna fishery management might also consider fishery management of Eastern Little Tuna or other species with overlapped habitats.

Population structure of Indian river shad, Gudusia chapra (Hamilton, 1822) from the Rupsha River, south-west Bangladesh

The Indian river shad, Gudusia chapra, is a well-known species of potamodromous fish belonging to the Clupeidae family. The main focus of this study is to state the sex ratio, growth pattern, length-length relationship, form factor, Fulton’s condition factor and relative weight of G. chapra harvested from the Rupsha River (south-west Bangladesh). Altogether 300 specimens (male=166 and female=134) were harvested with the help of commercial fisher folks on seasonal basis (summer, rainy and winter) during 2022. Body weight and length of individual specimen were recorded with digital balance and measuring board. Total length varied between 12.7 to 16.5 cm for males and 13.0 to 17.3 cm for females. Further, body weight ranged between 15.82 to 42.48 g for male and 18.36 to 46.65 g for female. As a whole, both sexes revealed positive allometric growth pattern (b>3.00). Moreover, the length-length relationships were found highly correlated for both sexes. The estimated form factor was 0.0087 indicated fusiform body shape for G. chapra population. The mean Fulton’s condition factor was recorded close to 1 indicated a pleasant health condition for this species. Further, mean relative weight revealed a sound ecological atmosphere regarding prey-predator status. The research outcomes would be helpful to execute a sound management policy in the Rupsha River and connected ecosystem in the south-west Bangladesh.