Allometric Growth Pattern Research Articles

GROWTH PARAMETER ESTIMATES OF SEVEN SMALL INDIGENOUS FISH SPECIES FROM THE FOUR SELECTED FLOODPLAIN WETLANDS OF NORTH BIHAR, INDIA

Morphometric study of length-weight relationship (LWR) and condition factors (K) of selected seven fish species from the floodplain wetland ecosystem of North Bihar. In the present investigation, 656 fishes (four families and seven species) out of 1426 fish samples were examined from floodplain wetlands of North Bihar, India. The fish species were captured by local fishing gear (such as cast net, drag net, and bamboo traps) during June 2019 to January 2020. Salmostoma bacaila and Puntius shophore were the most abundant while Trichogaster fasciata and Esomus danricus constituted the least count in the fish catch. Length weight relationship’s b values varied from 0.72 to 3.24. The values of b indicated negative and positive allometric growth patterns, while the K values ranged between 0.80 and 1.28. Among the captured species Salmostoma bacaila, Esomus danricus, and Anabas testudineus recorded negative allometric growth (b<3) whose body shape tended to be thinner. It might be attributed to unsuitable habitat conditions for the developmental growth of these fishes. Current study provided the baseline data about LWR and K of fish species from the floodplain wetlands of Bihar, India. This biological parameter of fish species could help in ecosystem-based fisheries management system (EBFM) by avoiding juvenile fishing, minimizing mesh size, improving selective gear properties, and restricting explosion/chemicals in the flood plain ecosystem.

High nutrient utilization and resorption efficiency promote bamboo expansion and invasion

Bamboos are fast-growing, aggressively-spreading, and invasive woody clonal species that often encroach upon adjacent tree plantations, forming bamboo–tree mixed plantations. However, the effects of bamboo invasion on leaf carbon (C) assimilation, and nitrogen (N) and phosphorus (P) utilization characteristics remains unclear. We selected four different stands of Pleioblastus amarus invading Chinese fir (Cunninghamia lanceolata) plantations to investigate the concentrations, stoichiometry, and allometric growth relationships of mature and withered leaves of young and old bamboos, analyzing N and P utilization and resorption patterns. The stand type, bamboo age, and their interaction affected the concentrations, stoichiometry and allometric growth patterns of leaf C, N, and P in both old and young bamboos, as well as the N and P resorption efficiency. Bamboo invasion into Chinese fir plantations decreased leaf C, N, and P concentrations, C:N and C:P ratios, N and P resorption efficiency, and allometric growth exponents among leaf C, N, and P, while it only slightly altered N:P ratios. PLS-PM analysis revealed that bamboo invasion negatively impacted leaf C, N, and P concentrations, as well as N and P utilization and resorption. The results indicate that high N and P utilization and resorption efficiency, along with the mutual sharing of C, N, and P among bamboos in interface zones, promote continuous bamboo expansion and invasion. Collectively, these findings highlight the significance of N and P utilization and resorption in bamboo expansion and invasion and provide valuable guidance for the establishment of mixed stands and the ecological management of bamboo forests.

Length-weight relationship and condition factor of Nile tilapia ( Oreochromis niloticus) fed diets supplemented with guava and star gooseberry leaf extract.

Nile tilapia ( Oreochromis niloticus) is predominant cultured species in aquaculture. However, there is a scarcity of literature regarding relationship between guava and star gooseberry leaf extract and the condition factor. Thus, the present study aims to investigate the effect of guava and star gooseberry leaf extract-supplemented diets on the specific growth rate, length-weight relationship, and condition factor of Nile tilapia. Six hundred and thirty Nile tilapia (8.7±0.4 g) were randomly distributed among twenty-one tanks (30 fish per tank) within a recirculation system. Over a 60-day period, the fish were fed diets supplemented with 5g/Kg and 10g/Kg of guava leaf extract (GLE-5, GLE-10), star gooseberry leaf extract (SGLE-5, SGLE-10), and a mixture of both (MxLE-5, MXLE-10). Subsequently, specific growth rate, length-weight relationship, and condition factor were determined. After 60 days, the specific growth rate was significantly higher in all the GLE, SGLE, and MxLE groups compared to the control group. The final lengths and weights differed significantly both in the control group and all the GLE, SGLE, and MxLE groups. The analysis of the regression equation indicated a positive correlation (r = 0.970, 0.977, 0.976, 0.974, 0.974, 0.974, and 0.969) between the length and weight of Nile tilapia in the control group and in all the GLE, SGLE, and MxLE groups. The regression exponent " b" values in all the GLE, SGLE, and MxLE groups were >3, indicating a positive allometric growth pattern in Nile tilapia compared to the control ( b=2.866), which exhibited a negative allometry. The final condition factor values did not differ significantly in either the control group or any of the plant extract groups. Nile tilapia exhibited positive allometric growth patterns and maintained good health when fed with GLE, SGLE, and MxLE groups. Therefore, these plant extracts demonstrate suitability for commercial Nile tilapia production.

Growth Patterns, Status of Well-Being and Trend Analysis of Three Commercially Important Clupeid Species from Selangor Landing Port

Length-weight relationships (LWRs) and condition factors are vital to quickly understanding the fitness and well-being of fish. There is currently no available evidence on LWRs, condition factors and landing trend for these three species and an absence of this information will result in improper management and monitoring of fish species. In this study, the growth patterns, status of well-being and trend analysis of commercially important clupeid species from the west coast of Peninsular Malaysia were studied. Sardinella lemuru, Amblygaster sirm and Nematalosa japonica were selected due to high commercial value and conservation status. S. lemuru was specifically categorized as near threatened by the IUCN with decreasing global populations. Total length (cm) and body weight (g) of S. lemuru, A. sirm and N. japonica were accounted for in this study, which was obtained from the wet market in the west coast of Peninsular Malaysia. The relationships between length and, weight and, condition factors (Fulton’s, KF; relative condition factor, Kn; Allometric) were assessed. The allometric equation; W = aLb was used to evaluate the length-weight relationships while KF = 100W/Lb and Kn = W/aLb were used to estimate fish condition factor. ARIMA (1,1,1) and ARIMA (0,1,0) models were utilised to forecast the fish landing pattern until 2030. The results showed that the coefficient of determination R2 values varied between 0.263 (Sardinella lemuru), 0.5187 (Amblygaster sirm) and 0.8443 (Nematalosa japonica) and b values ranged from 0.0959 to 2.1005. From this, all three fish species have shown a negative allometric growth pattern b<3, reflecting a relatively slow growth rate and size of fish. No positive allometry was detected for any of the sampled fish species. A low value of relative condition factor (Kn < 1) suggests that all the fish species in this study have poor physical characteristics due to inadequate food resources, and unsuitable habitats for expansion of the fish population. Prediction based on Autoregressive Integrated Moving Average (ARIMA) model showed that N. japonica would increase gradually in the coming years, while S. lemuru would remain constant. This study contributes to the knowledge base for S. lemuru, A. sirm and N. japonica in the west coast of Peninsular Malaysia, and is crucial in terms of understanding the ecology of the habitat for supporting conservation strategies, and the restoration and management of these species in future.

Length–weight Relationship and Condition Factor of Silver Pomfret (Pampus argenteus), Damanganga Estuary, Daman

A study was conducted on the length-weight relationship and condition factor of the commercially important fish, Silver Pomfret (Pampus argenteus), in the Damanganga estuary in Daman. Fish samples were collected from January 2021 to March 2021, with a total of 330 randomly sampled fish collected from fishermen. The average total length was 23.309±0.775 cm and the average total weight was 259.606±20.144 grams measured using standard methods. The 'b' value of Pampus argenteus showed a negative allometric (b<3.0) growth pattern, with the total length being positively correlated with the total weight of the fish (r²=0.829). The growth pattern was negative allometric while the Fulton condition factor (2.03±0.114) indicated good condition. Therefore, further studies on the length-weight relationship should focus on the sustainable management of the fisheries.

A Study of Length-Weight, Relationship and Condition Factor of Bagrus Bayad in Kiri Reservoir Shelleng Local Government Area Adamawa State, Nigeria

The Bagrid fishes are commonly known as naked catfishes, they are commercially important species found in Nigeria fresh waters especially in Rivers and Lakes such as Niger, Kaduna, Benue, Lake Chad, and other inland waters. The study is aimed at investigating the length- weight, relationship and condition factor of Bagrus bayad. A total of 282 individuals of B. bayad were randomly sampled for a period of 6 months. B. bayad sample collected were dissected. All the data collected were subjected to one-way analysis of variance (ANOVA). Descriptive statistic, regression analysis, graph (bar chart) mean and standard deviation were used in calculating the data for analysis. Result from the data analysis showed the slope (b) value for male = 1.996 which is less than 3.0, hence the male fish shows a negative allometric growth pattern. While that of the female showed that the b value was 3.2971 which is positive allometric growth pattern and the combined sexes analysis shows that b = 2.330, which indicated a negative allometric growth pattern. The condition factors showed that the Male has K = 2.893, Female has K = 3.122 and the Combined Sexes Condition factor is K = 3.002. B. bayad exhibited both negative and positive allometric growth pattern with a strong positive correlation between the total length and weight of the species and also the species are in good physiological condition in the Reservoir.

RELATIONSHIP BETWEEN LENGTH AND WEIGHT AND CONDITION FACTORS OF SCAD FISH (Decapterus Russelli) CATCH OF PURSE SEINE IN LAMPUNG BAY AT KM.GUNUNG JATI

The rate of exploitation of scads fish has increased, giving rise to concerns that the recruitment process is overfished. Relationship between length and weight in fisheries is one of the complementary information that needs to be known in relation to fisheries resource management. The purpose of this practice are to know the composition of yield, growth pattern catch of fly fish (Decapterus russeli) in the Lampung Bay. Sampling by simple random method were conducted in December until mid-March 2020. Samples consisted of catches from Lampung bay ships landed at the Lempasing fishing port. Data analysis by Linear Allometric Models (LAM), relative condition factors and fultons. The results showed the fly fish (Decapterus russeli) had a negative allometric growth pattern in December with a value of b = 2,7244, January with a value of b = 2,7153, February with a value of b = 2,8918, and in March with a value of b = 2,7067 value of 100,82-101,16 from relatively high relative condition factor and value of 2,85-2,91 from fulton condition factor which supports abundant feed which supports the life of Deccapterus russeli fish in good condition.

Reproductive Biology of Two Species Spiny Lobster in Donggala Waters Central Sulawesi

Spiny lobster species Panulirus versicolor and P. femoristriga in Donggala waters are reported to experience growth overfishing and recruitment overfishing. If this phenomenon continues, it will gradually reduce the spiny lobster population and result in an overall population decline. Information on reproductive biology is needed in the formulation of management and conservation policies for spiny lobsters in Donggala Waters, Central Sulawesi Province. The purpose of this study was to compare and analyze aspects of reproductive biology such as sex ratio, length-weight relationship, and spiny lobster condition factors. The research was conducted from July to December 2020 in the waters of Kabonga Village, Banawa Subdistrict, and Limboro Village, Central Banawa Subdistrict, Donggala District, Central Sulawesi Province. Reproductive biology data analysis applies several analytical models such as Chi-square, linear regression, Fulton condition factor, and Withney-Mann Test. The results showed no difference in sex ratio (balanced population) with negative allometric growth pattern and Fulton's condition factor in good condition (wellbeing) throughout the study in both P. versicolor and P. femoristriga. Population balance is important to ensure the continuity of recruitment, which is supported by adequate food availability, thus maintaining the stability of the spiny lobster population.

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.