Allometric Research Articles

Biomass Allocation in Gentianella turkestanorum is Driven by Environmental Factors and Functional Traits

Exploring the elevation distribution characteristics, biomass allocation strategies, and the effects of elevation, soil factors, and functional traits on the biomass of Gentianella turkestanorum (Gand.) Holub is of great significance for the production, development, utilization, and protection of the medicinal material resources. In this study, we investigated the biomass and functional traits of the root, stem, leaf, and flower of G. turkestanorum, analyzing their elevation distribution patterns, allometric growth trajectories, and their correlations. The results showed that the biomass of different organs of G. turkestanorum decreases with increasing elevation, and the belowground biomass/aboveground biomass increases with elevation. The flower biomass accounts for 59.24% of the total biomass, which was significantly higher than that of other organs. G. turkestanorum biomass follows the optimal allocation theory, adopting a ‘pioneering’ growth strategy at low elevations and a ‘conservative’ strategy at high elevations. Chlorophyll content and leaf thickness of G. turkestanorum were positively correlated with elevation, but leaf dry matter content and the number of flowers were negatively correlated with elevation. Compared to functional traits, elevation and soil factors have a stronger explanatory power regarding the biomass of G. turkestanorum. Elevation, soil moisture content, pH, available phosphorus, total nitrogen, and ammonium nitrogen significantly affect the biomass of G. turkestanorum, with only pH showing a positive correlation with biomass. Among these factors, elevation, soil moisture content, and pH significantly impact the accurate prediction of G. turkestanorum biomass. The number of flowers, crown width, root length, root diameter, and leaf dry matter content all have a significantly positive correlation with the biomass of G. turkestanorum, with the number of flowers and root diameter making significant contributions to the accurate prediction of biomass. Elevation can directly affect the biomass of G. turkestanorum and can also indirectly affect it through other pathways, with the direct effect being greater than the indirect effect.

Sugarcane Yield Estimation Using UAV-Based RGB Images and Allometric Equations

Accurately estimating pre-harvest sugarcane yield has long been a challenge. There are many methods for predicting sugarcane yield, ranging from simple empirical equations to complex physiological models. This paper reports a study on a method for predicting sugarcane yield using allometric equations combined with UAV-based RGB images (UAVI). UAVI were used for the estimation of the sugarcane height, which is in the form of the sugarcane height model (HM). Sugarcane height is one of the key factors in calculating sugarcane yield in the allometric equation. The results showed that the HM could be used in the allometric equation. There was only a slight discrepancy compared to measurement with a tape measure in the field. In developing the allometric equation, the authors created regression models to estimate aboveground biomass weight in leaf bush (Wl) and millable stalk (Wms) based on sugarcane height (H) and diameter measured from the first segment of sugarcane aboveground (Dfs). The model estimated aboveground biomass weight sufficiently for all stages of cultivation. Based on this model, the authors developed two general equations: Y = 0.0842 H * Dfs0.9827; R2 = 0.93 (used for leaf bush), and Y = 0.1254 H * Dfs1.3926; R2 = 0.93 (used for millable stalk). The decision correlation coefficient (R2) was 80% reliable. The HM models were slightly different from field measurements with a tape measure. Also, there was a little inaccuracy in the root-mean-square error (RMSE) between the sugarcane heights analyzed from UAVI and field measurements using tape measure. The RMSE values, arranged from highest to lowest according to the sugarcane growth stage were: 0.35 m (tillering phase, TP), 0.25 m (grand growth phase, GP), and 0.24 m (ripening phase, RP). Using the HM value in the allometric equation effectively estimated the sugarcane yield at different growth stages. Sugarcane growth at TP and GP phases gave the highest sugarcane yield at 200 cm of the HM value, with total yields of 11.49 and 16.75 ton/hectare, respectively. Whereas, RP gave the highest sugarcane yield at 350 cm of the HM value (total yield at 42.97 ton/hectare). Overall, an accurate estimation of the aboveground biomass of leaf bush and millable stalk can be obtained using these equations. The authors believe that the research methods presented here can help sugarcane farmers to better estimate yield prior to harvest.

The Potential Ecological Impact of Oil Palm Agroforestry as Term of Improvement for Restoring Harapan Rainforest

Around 20.000 ha of forestland in the Harapan Rainforest, Jambi Province, Indonesia, is currently under encroachment by local communities. Local communities encroach on forest land converted into oil palm plantations. Expanding oil palm plantations into forest areas led to biodiversity loss and massive carbon emissions. The annual net carbon emissions of oil palm transformation from the forest in Indonesia is around 12.41–25.83 ton-1 ha-1 year-1. Oil palm agroforestry is considered to be able to increase carbon sequestration and the biodiversity level. CRC-990/EFForTS has established an oil palm agroforestry experimental plot in Jambi Province, Indonesia, namely B11 plot. This study compares the carbon sequestration and biodiversity level between oil palm monoculture and agroforestry. The data collected in this study was obtained from the CRC-990 experimental plots. We collected data on the CRC-990 oil palm agroforestry plot in 6 plots of 40 m × 40 m and 6 plots of 20 m × 20 m. We chose the location and theme of this research because, until now, no research has been conducted yet to calculate the potential carbon absorption capacity and biodiversity level of oil palm agroforestry patterns in B11 plot. This study uses an allometric equation and IPCC guidelines to estimate biomass and carbon sequestration. SNI 8014 is used to evaluate the biodiversity level. This study found that oil palm agroforestry has more significant carbon sequestration. Increasing intercropping in oil palm agroforestry will increase the amount of carbon sequestration. This study also found that oil palm agroforestry has a higher biodiversity level. The species diversity of oil palm agroforestry is moderate, while oil palm monoculture is low. These potential ecological impacts can be considered an initial step in restoring the Harapan Rainforest. It is important to choose appropriate intercrops and proper management to increase the successful implementation of oil palm agroforestry.

Ontogenetic change in body shape for white sharks, Carcharodon carcharias, in Australian waters.

The analysis of how biological shape changes across ontogeny can provide us with valuable information on how species adapt behaviorally, physiologically, and ecologically. The white shark Carcharodon carcharias is one of the largest and most widely distributed apex predators globally, yet an understanding of ontogenetic changes in body shape and relative scaling of length and weight measures is limited, especially in relation to foraging ecology. Through analysis of a suite of shape-related metrics, we identified ontogenetic patterns of scaling throughout development. Isometric growth was exhibited for most metrics, failing to show a significant deviation from an isometric slope of 1.0 for length-length relationships, and 3.0 for weight-length relationships. The most notable difference from this trend was the negative allometric growth observed for the upper caudal-fin lobe length, trunk length, and the mouth length. The surface area of the fins also presented a strong, positive relationship with precaudal length (PCL) and the girth at the pectoral fin. Negative allometric growth was exhibited for three of the fins (pectoral, upper caudal fin, and lower caudal fin) against PCL, exhibiting a significant deviation from the expected isometric growth of 2.0 for area-length relationships. There were no significant differences in morphometric relationships between geographic regions within Australia that samples were collected from. No differences between the sexes were identified; however, this may be an artifact of the lack of mature animal samples. Conversely, life stage was found to have a significant effect on the girth-length and weight-length relationships. The development of regression equations for morphometric measures allows the assessment of white shark body condition and may serve as an assessment tool to understand the potential impacts of human-induced environmental change on white sharks.

Morphological and ecological approaches in reproduction of the endemic catfish of the eastern Amazon.

This study aimed to describe reproductive ecology based on morphological aspects of Peckoltia oligospila in stream rapids, eastern Amazon. A total of 186 fish (75 males and 111 females) were collected. The sex and gonadal maturity stage of these specimens were obtained based on histological characteristics of the gonads. The sex ratio, gonado-somatic index (GSI), relative frequency of the different maturity stages, size at first sexual maturation, condition factor of the population, and fluviometry were evaluated during the study. There was a significant female frequency during the study. The population exhibited positive allometric growth without differences between sexes. GSI and relative frequency showing a reproductive period synchronized in February, and the species exhibited parcelated spawning. L50 was estimated at 5.85 and 7.39 cm for females and males, respectively. There were significant differences in the condition factor only in females that showed a highest value in August. Thus, based on the results P. oligospila has an intermediate strategy between the opportunistic and equilibrium strategies.

Transcriptome Reveals Molecular Mechanisms of Neuroendocrine Regulation of Allometric Growth in the Red Swamp Crayfish Procambarus clarkii.

Allometric growth is a typical characteristic of crustaceans, which mainly occurs among individuals, life stages, tissues, and between sexes. The red swamp crayfish Procambarus clarkii is an economically important crustacean species in the world. To date, the molecular regulatory mechanisms of neuroendocrine system in the allometric growth of P. clarkii remain unclear. In this study, P. clarkii exhibiting significant allometric growth among individuals were sampled from three full-sibling families. The brain, eyestalk, nerve cord, and Y-organ were dissected for transcriptome analysis. Key functional genes were identified by random forest and DESeq2 methods. The gene pathways were enriched utilizing Kyoto Encyclopedia Genes and Genomes (KEGG) analysis. Gene topological analysis was established through weighted gene co-expression network analysis (WGCNA), and hub genes were screened by protein-protein interaction (PPI) networks. Transcriptomic analysis results were validated via qRT-PCR. RNA-Seq identified 31 differentially expressed genes (DEGs) (7 up- and 24 downregulated); 301 DEGs (23 up- and 278 downregulated); 1308 DEGs (474 up- and 834 downregulated); and 64 DEGs (52 up- and 12 downregulated) in the brain, eyestalk, Y-organ, and nerve cord, respectively. Crucial functional genes such as CHIA in the brain and perlucin-like in the eyestalk were notably identified. WGCNA revealed two hub modules, while PPI networks identified neuroendocrine regulators module which hub genes mainly including CP1876-like and cuticle protein AM1199-like, and structural components module which hub genes mainly including CUB& CCP Domain-Containing Protein, ARRDC, and E3 Ubiquitin protein ligase MCYCBP2-like. Correspondingly, the significant gene pathways such as amino sugar and nucleotide sugar metabolism (pcla00520) and insect hormone biosynthesis (pcla00981) were enriched. The results revealed the complex interactions and regulatory relationships of hub genes within hub modules to coordinate molting and growth. The results of RNA-Seq analysis were validated by the consistency of gene expression in qRT-PCR. In present study, key functional genes in the neuroendocrine system regulating allometric growth among individuals were identified, and significant pathways mainly include hormone synthesis were screened, thus constructing a neuroendocrine molecular regulatory network for the allometric growth of P. clarkii. Building on these investigations, a comprehensive mechanism whereby neuroendocrine regulators interact with structural components to coordinate molting and growth was proposed. The result would provide valuable insights into the molecular regulatory mechanisms of allometric growth, highlighting the interplay between the neuroendocrine system and relevant tissues.

Biological Aspects of Sphyraena sphyraena (L., 1758) in the Central Mediterranean (E. Ionian Sea)

S. sphyraena is a widely distributed species with low commercial value and no sufficient scientific knowledge of its biology. In the present study, the age, growth, weight–length relationship, otolith morphometry, and reproduction of the species were investigated in the Eastern Ionian Sea for the first time. The von Bertalanffy growth function parameters were L∞ = 63.65 cm, k = 0.14 year−1 and t0 = −2.01 years and Φ′ = 2.75. The negative allometric growth in weight was found. Slope b of the weight–length relationship was 2.634. For the otolith moprhometry, the variables radius, length, width, area, perimeter, roundness, circularity, form factor, rectangularity, and ellipticity were examined, which showed that the otolith shape is elongated with an elliptical and rectangular form. Six otolith variables (radius, length, width, area, perimeter, and ellipticity) showed a significant relationship with size. The sex ratio (females/males) was 1:0.74 (no statistically significant difference from 1:1), and the spawning season extended from April to June with peak values of GSI in May for females and April for males. The results of this work improve our knowledge of the species life cycle and provide basic information for species stock identification and fisheries management.

Estimation of carbon stock, biomass and CO2 sequestration at mangrove forest in Batu Rusa River and Serata Pasir Padi, Bangka Island

Abstract The aim of this research is to determine the total biomass, carbon stock and CO2 sequestration above ground in mangrove forests in the Baturusa and Pasir Padi River Basins. This research was carried out in October-September 2023-2024, using a non-destructive sampling method based on species-specific allometric equations to find the biomass value of mangrove stands. Data collections were determined using the random purposive sampling method. The result shows that Rhizophora apiculata is the mangrove species that dominates in the Baturusa River, while the Excoecaria agallocha dominates in the Pasir Padi River mangrove forest. The total biomass reserves above ground in the Baturusa River and Pasir Padi River mangrove forests are quite high, namely 195310.4 tonnes/ha, with 188172.2 tonnes/ha for the biomass of the Baturusa River mangrove stands while the mangrove stands in Pasir Padi are 7138.2 tonnes. /Ha. The total above-ground (standing) carbon stock in the Baturusa River mangrove forest is 88440.9 tonnes/ha while in the Pasir Padi River it is 3354.9 tonnes/ha with a total reaching 91795.9 tonnes/ha. The total uptake of CO2 sequestration in mangrove stands in the Baturusa River was 324283.4 tonnes/ha, the Pasir Padi River was 122301.5 tonnes/ha with a total reaching 336585.0 tonnes/ha. Sonneratia alba is a mangrove species that has the highest biomass reserves, carbon stock and CO2 sequestration, namely biomass of 0.701 tonnes/tree, carbon stock of 0.330 tonnes/tree and CO2 uptake of 1.208 tonnes/tree, because it has a fairly large trunk diameter compared to other mangrove species.

Assessment of River Ecological Health Status and Interbasin Water Transfer Potential: Case study of Luapula River Basin in Zambia

Water transfer is one mechanism for meeting increasing water demand in water-stressed areas. However, moving water from one area to another often disturbs the ecosystem including the fisheries biodiversity and growth patterns. Thus, when contemplating water transfer, baseline information on the status of the fisheries biodiversity and condition is cardinal for sustainable fisheries management during and after water transfer implementation. This work aimed at investigating the current fisheries condition (biodiversity, weight length relationship and condition factor) of the Luapula River Basin (LRB) to explore potential and implications for future interbasin water transfer on the basin fisheries. The fishes were sampled during the 2022/2023 dry and wet season at selected sites in LRB. Biodiversity indices, fish weight/length relationship and condition factor were used to describe the fish biodiversity, growth patterns and wellbeing which described the status of the aquatic condition of the donor basin. Species Richness, Shannon Diversity Index, Simpson Index and Evenness ranged between 0.8902 to 1.664, 0.9167 to 2.1437, 0.4416 to 0.8683 and 0.4172 to 0.8940 respectively. The growth coefficient (b) ranged from 1.223 to 3.755 indicating negative and positive allometric growth. The condition factor ranged between 0.692 and 2.218. Thus, it can be said that the LRB has good fish biodiversity albeit with some species showing dominance, normal growth pattern and wellbeing showing bias towards undisturbed habitats and physiological state. As such, this status quo of LRB needs to be maintained prior to, during and after IBWT implementation.

Root Biomass Allocation and Carbon Sequestration in Urban Landscaping Tree Species in South Korea

The quantification of urban tree biomass allocation has primarily relied on estimations using allometric equations (AEs) developed for nondestructive harvest methods. However, the lack of harvest-based AEs that account for belowground biomass, nutrient concentration, and annual growth rates poses challenges in accurately quantifying the greenhouse gas inventory for urban land uses. In this study, we aimed to develop AEs using a log-transformed linear model for eight urban landscaping tree species, taking into account belowground biomass. We purchased 117 urban landscaping trees from tree farms in South Korea and investigated their biomass fractions, carbon and nutrient concentrations, and annual growth rate using a destructive method. We also developed AEs for different tree compartments using diameter at breast height as an independent variable. The AEs obtained exhibited high suitability, as evidenced by their high R2 values (0.853–0.982 and 0.806–0.923 for aboveground and belowground biomass, respectively). The mean belowground biomass fraction across the different species was approximately 30%, suggesting that urban trees could allocate more belowground biomass than forest trees. Conversely, carbon and nitrogen concentrations varied significantly across species and compartments, and the mean annual carbon sequestration rate was 3.96 kg C year−1 tree−1. Therefore, the application of the AEs for urban trees may enhance the accuracy of the national greenhouse gas inventory for the settlement sector.

Length-weight Relationship and Condition Factor of Clarias gariepinus, Mormyrus rume and Synodontis budgetti in Dadin Kowa Reservoir, Gombe State, Nigeria

Length-weight relationship and condition factor of Clarias gariepinus, Mormyrus rume rume and Synodondis budgetti were carried out for a period of eighteen month, (October 2022 to March 2024) in Dadin Kowa Reservoir. A total of 189 specimens of C. gariepinus, 81 specimens of M. rume and 272 specimens of S. budgetti were purchased from the local fishermen as soon as they returned from their catch and were brought immediately to the laboratory for analysis. The objective of the study is to determine the physiological well-being of the fishes in Dadin-Kowa reservoir. The length weight relationship of these species were calculated using the equation: W = aLb. Condition factor were calculated using the formula, K= 100W/L3. Regression gained of value b shows the growth patterns of C. gariepinus as negative allometric growth and isometric growth with values ranging from 2.430908 to 3.203496. M. rume as negative allometric growth, isometric growth and positive allometric growth with values ranging from 0.155529 to 4.409502 and S budgetti as negative allometric growth, isometric growth and positive allometric growth with values ranging from 2.465982 to 4.174956. The condition factor of C. gariepinus ranges from 0.05-10.26, M. rume, 0.03- 9.61 and S. budgetti from 0.02- 6.67 indicating that some are in good physiological condition while others are not.

A Study on Water Quality in Relation to Length-weight Relationship and Relative Condition Factor of Two Fresh Water Fishes- Labeo Rohita and Oreochromis Niloticus in Krishna Raja Sagara Reservoir

Fish being the cheapest source of protein, the population explosion and economic pressure demands increase in fish yield. Since biotic and abiotic factors have influence on growth and well-being of fish, there is a need to continuously monitor the fish culture water bodies for physico-chemical water quality parameters and presence of pollutants. This work shows the allometric growth (cube rule) and well-being of two fresh water fishes Labeo rohita and Oreochromis niloticus and whether or not the deviation if any from cube rule is accompanied by altered water quality required for fish culture. This study reveals that majority of the physico-chemical water quality parameters namely temperature, pH, turbidity, conductivity, DO, BOD, TSS and phosphate were within the optimal range for fish culture, whereas nitrate levels were higher than the desired levels. These results indicate near normal growth and well-being in L. rohita as well as in O. niloticus in the prevailing environmental conditions in the KRS reservoir.

Non-Linear Models for Tree Aboveground Biomass and Volume Estimation in Agoi-Ibami Forest Reserve, Cross River State, Nigeria

Tree biomass and volume estimation based on allometric equations is a widely used non-destructive technique for estimating biomass, sequestered carbon, and volume worldwide. Non-linear models for the biomass and volume of individual trees in Nigeria's Cross River State's Agoi-Ibami Forest Reserve were fitted and validated in this study. In this study, two parallel lines transect of 1500 meters in length, separated by 500 meters, were established using the systematic line transects sampling method. Along each transect, ten sample plots, each measuring 50 m by 50 m, were placed alternately at 100 m intervals. Twenty sample plots in all were thus marked for the study. The estimation of biomass using a non-destructive method was used. To calculate the aboveground green biomass for each, the diameter at breast height and total height were employed. Agoi-Ibami Forest Reserve had a total value of 391N ha-1 for number of stem per hectare, 14 tree families, mean dbh of 26.04cm, height of 15.9m, and basal area of 50.21m2ha-1. Conversion factors were used to estimate stand biomass, carbon sink, and sequestered carbon dioxide (CO2). Non-linear models were fitted for volume and aboveground biomass estimation in the study area. All of the models were evaluated and validated using some assessment statistical criteria and residual graphs, and models with good fit were suggested for use. Curve Expert Software was used for the development of the non-linear regression models. According to the assessment criteria, the forest reserve's best non-linear volume and aboveground biomass models were the Ratkowsky, Weibull, and Logistic models. Fitted models should therefore be employed for the forest reserve's efficient and successful management.

Length–Weight Relationship and Spatiotemporal Distribution Pattern of Three Schizothoracinae Fishes Along the Nujiang River in the Qinghai–Tibetan Plateau, China

The Qinghai–Tibet Plateau (QTP) is a unique ecological area that has faced issues like diminishing ecosystem stability and increasing pressures on resources and the environment. These issues have arisen as a result of the combined impact of global warming and human activities in recent times. The study of the growth and distribution patterns of schizothoracinae fishes can support guiding policy decisions about the conservation of aquatic species and ecological habitats in the QTP. The investigation on fish resources was carried out in the QTP section of the Nujiang River during the spring and autumn seasons of 2017, 2018, and 2019. A total of seven sampling sites were established based on variations in elevation. According to length–weight relationship (LWR) analysis, Schizothorax nukiangensis mainly displayed a negative allometric growth while Ptychobarbus kaznakovi and Schizopygopsis thermalis mainly showed near isometric growth or positive allometric growth in the QTP section of the Nujiang River. Due to temperature and food abundance, the three schizothoracinae fishes showed better growth performance in autumn than spring. Spatial heterogeneity exhibited a greater influence on the LWR of S. nukiangensis and P. kaznakovi than seasonal variation. In contrast, seasonal variation on S. thermalis showed greater influence than spatial heterogeneity. According to the linear mixed effect model (LMM), both spatial factors and seasons had influence on fish growth in the QTP. Schizothorax nukiangensis was identified as the predominant species from CWL to BS, spanning an altitude range of 1800 to 2700 m. Ptychobarbus kaznakovi was identified as the main species at LL, BB, and BR, occupying an altitude range of 2700 to 3800 m. Schizopygopsis thermalis is primarily distributed at altitudes beyond 4000 m and along the tributary river Yuqu. Principal coordinates analysis (PCOA) and nonmetric multidimensional scaling (NMDS) divided schizothoracinae fish populations into three clusters by spatial differences. Redundancy analysis (RDA) and Monte Carlo Permutation analysis revealed that habitat elevation and water temperature had a significant impact on schizothoracinae fish distribution. This article enhances our understanding of the distribution and environmental adaptation of indigenous fish in the Qinghai–Tibet Plateau.

Using a length-weight relationship based on wild lumpfish (Cyclopterus lumpus L.) for estimation of body condition of lumpfish in salmon cages.

The use of lumpfish (Cyclopterus lumpus L.) as cleaner fish in Atlantic salmon aquaculture has emerged as a promising solution to combat the issue of sea lice infestation, as they have proven effective under the right conditions. The aquaculture industry, however, is facing challenges in ensuring the welfare and survival of lumpfish in salmon cages. Part of the welfare monitoring of lumpfish is the estimation of body condition. Previous research on standard length-weight relationships for lumpfish has primarily relied on the growth patterns of lumpfish in salmon cages, which might not align with the natural growth patterns of the fish. In this study, we argue for another perspective: using the standard weight of wild lumpfish to estimate the body condition of lumpfish in salmon cages. We assert that this approach aligns more closely with the natural growth pattern of the fish and may offer a more accurate representation of their condition. Our findings show significant differences in growth patterns between wild lumpfish, which show positive allometric growth, and those in salmon cages, which show slightly negative allometric growth. The findings underscore the importance of using appropriate length-weight relationships for lumpfish in aquaculture to ensure an accurate assessment of their body condition.

Aspects of Growth, Diet, and Reproduction of <i>Oreochromis niloticus</i> (Linnaeus, 1758) in a Hypertrophic Milieu, the Municipal Lake of Yaoundé, Cameroon

The Nile tilapia, <i>Oreochromis niloticus</i>, is a highly valued fish species in Africa for subsistence and commercial purposes. However, overfishing activities in non-supervised lakes or reservoirs threaten its availability. In the view of contributing to the database on the life history traits of this species in Cameroon and supporting its sustainable management, the present study investigated the growth patterns, food preferences, and reproductive aspects of <i>O. niloticus</i> in a hypertrophic milieu, the Yaoundé Municipal Lake, from May to October 2018. Fish specimens were sampled, measured, weighed, and sexed. The digestive tract of each specimen and the females’ gonads were collected. The intestines were measured, and the stomach contents were identified. The females’ reproductive aspects were determined. Overall, 101 specimens were collected and distributed among 48 (47.5%) males and 53 (52.5%) females, with a sex ratio of 1: 1.1. In this hypoxic (1.35 ± 0.4 mg/L) and highly conductive (210.5 ± 56.9 µS/cm) milieu, <i>O. niloticus</i> displayed a relatively good condition (<i>Kn</i> > 1) throughout the sampling period and negative allometric growth patterns for both sexes (<i>b </i>< 3; <i>p</i> < 0.001). Materials from plant origin were the preferred prey types, with an index of relative importance (IRI) of 78.20%; meanwhile, mud and materials from animal origin were secondary prey items (IRI: 13 ‒ 17%). The relative gut length (RGL) value above 3.0 and the foraging activity on detritus suggest that <i>O. niloticus</i> has an herbivorous or detritivorous dietary habit and is a bottom-feeder. Female length at first maturity (L<sub>50</sub>) was 17 cm. Their gonado-somatic index (GSI) showed sexual activity throughout the whole sampling period, with the peak spawning phase happening in August. The absolute fecundity of gravid females varied between 316 and 1816 oocytes (942 ± 430 oocytes), and the relative fecundity ranged from 1–5 oocytes/gram of body weight (3 ±1 oocytes/g). The results highlight the performance of the Nile tilapia in this ecosystem and provide information for its sustainable use and improvement of fish culture.

Length–weight relationships for 11 freshwater fish species (Actinopterygii) from four protected areas, northern Vietnam

The length–weight relationships (LWRs) of 11 fish species from one national park and three nature reserves, in northern Vietnam, totaling 737 individuals between October 2018 and November 2021, are described in this study. The following species, representing 11 genera and seven families, were studied: Aphyocypris normalis Nichols et Pope, 1927, Barbodes semifasciolatus (Günther, 1868), Beaufortia pingi (Fang, 1930), Carassius auratus (Linnaeus, 1758), Glyptothorax honghensis Li, 1984, Hemibarbus medius Yue, 1995, Macropodus opercularis (Linnaeus, 1758), Neolissochilus benasi (Pellegrin et Chevey, 1936), Onychostoma gerlachi (Peters, 1881), Opsariichthys minutus Nichols, 1926, Rhinogobius duospilus (Herre, 1935). All regressions were highly significant (P < 0.001). Positive allometric growth was seen in six species (b > 3, P < 0.01) and isometric growth in five species (b = 3, P > 0.05). This is the first report on the LWRs of six fish species, including Beaufortia pingi, Barbodes semifasciolatus, Neolissochilus benasi, Opsariichthys minutus, Glyptothorax honghensis, and Rhinogobius duospilus from four conservation areas. The presently reported study provides foundational data for future stock assessment works and management initiatives in protected areas, as well as facilities comparisons of LWRs from different habitats.

An Assessment of the Carbon Budget of the Passively Restored Willow Forests Along the Miho River, Central South Korea

Climate change is rapidly progressing as the carbon budget balance is broken due to excessive energy and land use. This study was conducted to find and quantify new carbon sinks to implement the carbon neutrality policy prepared by the international community to solve these problems. To reach this goal, an allometric equation of the willow community, which dominates riparian vegetation, was developed and applied to calculate the net primary productivity of the willow community. Furthermore, after the amount of carbon emitted via soil respiration was quantified, the net ecosystem production was calculated by subtracting the amount of soil respiration from the net primary productivity. In comparisons of the results obtained via this process with those obtained from forest vegetation, the willow community, representative of riparian vegetation, showed a much higher carbon sequestration rate than forest vegetation. Considering these results comprehensively, the willow community could be a new and significant carbon absorption source. In this context, proper river restoration should be realized to contribute to carbon neutrality and secure various ecosystem service functions.

Estimating canopy fuels across Europe with satellite data and allometric equations

Estimating canopy fuels across Europe with satellite data and allometric equations

Potentially toxic elements (PTEs) in the invasive Asian clam (Corbicula fluminea) from polluted urban river areas of Bangladesh and evaluation of human health risk.

The invasive Asian clam species, Corbicula fluminea, has significant ecological and societal implications at both local and international levels due to its nutritional aspects. C. fluminea from four urban rivers in Bangladesh exhibited negative allometric growth and degree of contamination with potentially toxic elements (PTEs), which posed a concern to human health based on the AAS and USEPA risk models. The highest mean concentration of PTEs followed a decreasing order: Zn (155.08 ± 4.98mg/kg) > Cu (53.96 ± 7.61mg/kg) > Mn (14.29 ± 3.25mg/kg) > Cd (2.23 ± 0.10mg/kg) > Pb (1.64 ± 0.14mg/kg) > As (1.51 ± 0.45mg/kg) > Ni (1.25 ± 0.27mg/kg) > Cr (0.65 ± 0.02mg/kg) in C. fluminea and raising safety concerns. With the exception of Cr and Mn, all element levels were exceeded safety guideline value (SGV) (mg/kg. ww) and exhibited a strong positive correlation (p < 0.05) among the sites. The target hazard quotient of Mn is THQ > 1, and As showed a non-carcinogenic risk in children at OBR, BR, and MR site. The hazard index (HI > 1) value at the BR and MR sites indicated a public health risk associated with the clam. The target cancer risk (TCR) values for As, Cd, and Ni showed that consuming clams posed a carcinogenic risk to human health. These findings suggest that eating these clams may put consumers at significant risk for health issues related to As, Cd, Ni, and Mn exposure. The study emphasizes the need for strict monitoring and preventative measures to reduce the health risks posed by PTEs contamination in clams.