Search Results (17)

Depensation (or an Allee effect) has recently been detected in stock–recruitment relationships (SRRs) in four Atlantic herring stocks and one Atlantic cod stock using a Bayesian statistical approach. In the present study, we define the Allee effect threshold (B_AET) for these five stocks and propose B_AET as a candidate limit reference point (LRP). We compare B_AET to traditional LRPs based on proportions of equilibrium unfished biomass (B₀) and biomass at maximum sustainable yield (B_MSY) assuming a Beverton–Holt or Ricker SRR with and without depensation, and to the change point from a hockey stick SRR (B_CP). The B_AET for the case studies exceeded 0.2 B₀ and 0.4 B_MSY for three of the case study stocks and exceedances of 0.2 B₀ were more common when the Ricker form of the SRR was assumed. The B_AET estimates for all case studies were less than B_CP. When there is depensation in the SRR, multiple equilibrium states can exist when fishing at a fixed fishing mortality rate (F) because the equilibrium recruits-per-spawner line at a given F can intersect the SRR more than once. The equilibrium biomass is determined by whether there is excess recruitment at the initial projected stock biomass. Estimates of equilibrium F_MSY in the case studies were generally higher for SRRs that included the depensation parameter; however, the long-term F that would lead the stock to crash (F_crash) in the depensation SRRs was often about half the F_crash for SRRs without depensation. When warranted, this study recommends exploration of candidate LRPs from depensatory SRRs, especially if Allee effect thresholds exceed commonly used limits, and simulation testing of management strategies for robustness to depensatory effects. Full article

Pakistan’s marine fishing industry is crucial to the country’s economy, generating employment opportunities and foreign revenue. It produces 80% of the country’s total fish production. Otolithes ruber is a commercially important fish on the Makran coast of Pakistan, contributing significantly to the region’s croaker fisheries. This study is the first to apply three length-based approaches for assessing the stock status of O. ruber in the Makran coast: (1) TropFishR to estimate the mortality, growth parameters, and current exploitation status, reference points based on the yield per recruitment model, (2) the length-based Bayesian biomass method (LBB) to calculate stock biomass, and (3) the length-based spawning potential ratio (LBSPR) to estimate the spawning potential ratio. The length–weight relationship of Otolithes ruber was a positive allometric pattern (b = 3.28; R² = 0.94). Growth parameters for Otolithes ruber were L_∞ = 55.47 cm, K = 0.50 year⁻¹. The calculated total mortality rate (Z), natural mortality (M), and fishing mortality (F) were 2.27 year⁻¹, 0.67 year⁻¹, and 1.6 year⁻¹, respectively. The exploitation rate (E) was 0.70, indicating severe overexploitation. The current length at first capture (Lc₅₀) = 27.37 cm was lower than that at first maturity (Lm₅₀) = 30.75 cm, indicating growth overfishing. The current spawning potential ratio (8%) was lower than the optimal value (40%), indicating recruitment overfishing. The current biomass, concerning virgin biomass B/B_o, was also 8%, resulting in a 92% stock decline. We recommend reducing the exploitation pressure by limiting the commercial catch to an optimum length range of 34.5–42.2 cm and reducing fishing pressure by 40% to ensure sustainable fishery management. Full article

Background: Bipolar disorder (BD) and borderline personality disorder (BPD) share common cognitive impairments. These deficits are also shared by bipolar offspring (BD-OFF). Nevertheless, little is known regarding the association between cognitive impairments and BPD features in youth with BD and BD-OFF. Objectives: This study aimed to investigate the association between BPD features and cognitive impairments in youth with BD and BD-OFF. Methods: Thirty-nine participants (7–17 years) with BD, 18 BD-OFF, and 50 healthy controls (HCs) were recruited. BPD features were assessed using the Borderline Personality Features Scale for Children (BPFS-C). Deficits in executive functions and affective processing were assessed using tasks from the Cambridge Neuropsychological Test Automated Battery (CANTAB), namely, the Cambridge gambling task (CGT), the stockings of Cambridge (SOC), and the Affective Go/No-Go (AGN) and rapid visual processing (RVP) tasks. Between-group differences were analyzed through ANOVAs. Relationships between the BPFS-C and cognitive tasks were examined using multiple linear regressions in youth with BD and BD-OFF. Results: Youth with BD and BD-OFF showed higher scores on the BPFS-C. Youth with BD had increased deficits in the CGT and SOC compared to HCs. In both youth with BD and BD-OFF, BPD features were associated with increased deficits in the CGT, and a bias toward positive emotions in the AGN task. Conclusions: In youth with BD and BD-OFF, clinical and cognitive assessments for BPD features are of relevance as they have the potential to inform targeted interventions. Full article

Stock–recruitment relationships depend on the total abundance of females, their fecundity, and patterns of their maturation. However, the effects of climatic conditions on the abundance, biomass, and mean weight of female red king crabs, Paralithodes camtschaticus, from the introduced population (Barents Sea) have not yet been studied. For this reason, we analyzed long-term fluctuations in stock indices and the average weight of an individual crab in a small bay of the Barents Sea and related these parameters to the dynamics of temperature conditions (temperature in January–December, mean yearly temperature, and temperature anomaly) in the sea. The average weight of a crab at age 6–9 had strong negative correlations with water temperature at lags 8 and 9, indicating faster female maturation in warm periods. Positive relationships were registered between temperature and stock indices for 15–19-year-old females at lag 4 and for 10–14-year-old females at lag 10, supporting the idea of higher survival rates of juveniles and their rapid development being a response to a pool of warm waters. Both redundancy and correlation analyses revealed seawater temperatures in June–August being the most important predictors of female abundance and biomass, indicating that favorable temperature conditions in the first 3 months of crab benthic life result in high survivorship rates for red king crabs. Full article

This study establishes a climate-sensitive transition matrix growth model and predicts forest growth under different carbon emission scenarios (representative concentration pathways RCP2.6, RCP4.5, and RCP8.5) over the next 40 years. Data from the Eighth (2013) and Ninth (2019) National Forest Resource Inventories in Chongqing and climate data from Climate AP are utilized. The model is used to predict forest growth and compare the number of trees, basal area, and stock volume under different climate scenarios. The results show that the climate-sensitive transition matrix growth model has high accuracy. The relationships between the variables and forest growth, mortality, and recruitment correspond to natural succession and growth. Although the number of trees, basal area, and stock volume do not differ significantly for different climate scenarios, the forest has sufficient seedling regeneration and large-diameter trees. The growth process aligns with succession, with pioneer species being replaced by climax species. The proposed climate-sensitive transition matrix growth model fills the gap in growth models for natural secondary forests in Chongqing and is an accurate method for predicting forest growth. The model can be used for long-term prediction of forest stands to understand future forest growth trends and provide reliable references for forest management. Forest growth can be predicted for different harvesting intensities to determine the optimal intensity to guide natural forest management in Chongqing City. The results of this study can help formulate targeted forest management policies to deal more effectively with climate change and promote sustainable forest health. Full article

Stock depletion level is an important concept in the assessment and management of exploited fish stocks because it is often used in conjunction with reference points to infer stock status. Both the depletion level and reference points can be highly dependent on the stock–recruitment relationship. Here, we show how depletion level is estimated in stock assessment models, what data inform the depletion level, and how the stock–recruitment relationship influences the depletion level. There are a variety of data that provide information on abundance. In addition, to estimate the depletion level, unexploited absolute abundance needs to be determined. This often means extrapolating the abundance back in time to the start of the fishery, accounting for the removals and the productivity. Uncertainty in the depletion level arises because the model can account for the same removals by either estimating low productivity (e.g., low natural mortality) and high carrying capacity or high productivity and a low carrying capacity, and by estimating different relationships between productivity and depletion level, which are strongly controlled by the stock–recruitment relationship. Therefore, estimates of depletion are particularly sensitive to uncertainty in the biological processes related to natural mortality and the stock–recruitment relationship and to growth when length composition data are used. In addition, depletion-based reference points are highly dependent on the stock–recruitment relationship and need to account for recruitment variability, particularly autocorrelation, trends, and regime shifts. Future research needs to focus on estimating natural mortality, the stock–recruitment relationship, asymptotic length, shape of the selectivity curve, or management strategies that are robust to uncertainty in these parameters. Tagging studies, including close-kin mark-recapture, can address some of these issues. However, the stock–recruitment relationship will remain uncertain. Full article

Continuous monitoring of lower extremity muscles is necessary, as the muscles support many human daily activities, such as maintaining balance, standing, walking, running, and jumping. However, conventional electromyography and physiological cross-sectional area methods inherently encounter obstacles when acquiring precise and real-time data pertaining to human bodies, with a notable lack of consideration for user comfort. Benefitting from the fast development of various fabric-based sensors, this paper addresses these current issues by designing an integrated smart compression stocking system, which includes compression garments, fabric-embedded capacitive pressure sensors, an edge control unit, a user mobile application, and cloud backend. The pipeline architecture design and component selection are discussed in detail to illustrate a comprehensive user-centered STIMES design. Twelve healthy young individuals were recruited for clinical experiments to perform maximum voluntary isometric ankle plantarflexion contractions. All data were simultaneously collected through the integrated smart compression stocking system and a muscle force measurement system (Humac NORM, software version HUMAC2015). The obtained correlation coefficients above 0.92 indicated high linear relationships between the muscle torque and the proposed system readout. Two-way ANOVA analysis further stressed that different ankle angles (p = 0.055) had more important effects on the results than different subjects (p = 0.290). Hence, the integrated smart compression stocking system can be used to monitor the muscle force of the lower extremities in isometric mode. Full article

Exploring the relationship between topography and forest multifunctionality enhances understanding of the mechanisms maintaining forest multifunctionality and proves beneficial for managing overall forest functions across different landscapes. Leveraging census data from a 20 ha subtropical forest plot, we investigated the topographic variations in individual functions, multifunctionality, and their interrelationships. Our results revealed that relative to lower elevations, higher elevations had higher woody productivity, sapling growth, and recruitment that drove higher average forest multifunctionality (FMA). However, forest multifunctionality at the 50% threshold level (FMt50) had no significant difference between high and low elevations. Compared with the valley and slope, higher woody productivity, higher sapling recruitment, and higher soil organic carbon stock drove higher forest multifunctionality (FMA and FMt50) in the ridge. These results indicate the ridge serves as a forest multifunctionality “hotspot” within the Tiantong 20 hm² plot. Additionally, relative to the low elevation, the degree of synergy among functions at the high elevation was significantly lower, indicating difficulties in attaining high forest multifunctionality at the high elevation. Our work underscores the importance of topography in regulating subtropical forest multifunctionality and relationships between forest functions at a local scale, suggesting that future forest management strategies (such as regulating synergistic or trade-off relationships between functions) should give particular attention to topographic conditions. Full article

Certain benthic polychaetes, such as species within the genus Namalycastis, are employed in the diet of gravid shrimps in aquaculture due to their amino acids and highly unsaturated fatty acid content, enhancing the quality of gravid shrimp. Despite its importance in the rapidly developing shrimp culture industry, the population parameters of this economically valuable species are unknown. Therefore, the present study examines the population parameters of Namalycastis fauveli to assess its occurrence, growth, recruitment, exploitation level, and stock status in Bangladesh. Monthly samplings of N. fauveli and environmental variables were collected from five sites of the Cox’s Bazar coast using a square-shaped mud corer with a 0.093 m² (or 1.0 ft²) mouth opening from August 2020 to July 2021 to measure or estimate. Within the 8.0–30.0 cm depth range of the intertidal zone, polychaete samples were collected from the sediment. The results showed negative allometric growth (b < 3), but there was a significant L–W relationship (p < 0.05, r² = 0.43 to 0.94). The estimated L_∝, K, and ϕ were 22.05 cm, 0.99 year⁻¹, and 2.69, respectively, while total mortality (Z) was 4.56 year⁻¹. It was calculated that the fishing mortality and capture probability proportionally increased with the total length at a certain age. Recruitment mostly occurred in October and March, and temperature had a greater impact than salinity. The evaluated exploitation level (E = 0.57) indicated that the stock was overexploited. Thus, the above results provide some valuable information for shrimp farmers and stakeholders, as well as for policymakers in the move towards restoration, species conservation, and efficient management of N. fauveli natural stocks. Full article

Japanese sardines (Sardinops melanostictus) are environmentally sensitive pelagic fish. We investigated the effects of environmental factors on the stock-recruitment (S-R) relationship of S. melanostictus in the Pacific Ocean from 1984 to 2018. We modeled and analyzed the recruitment of S. melanostictus using the Ricker model, the Ricker environment extension model (Ricker-E), and the generalized additive model (GAM). Different numbers of environmental factors were added to the models for fitting, and the Akaike information criterion (AIC) was used to select the optimal model. The results showed that the nonlinear GAM provided the best fit. The results of the GAM single factor and multifactor analysis showed that environmental factors were significantly correlated with recruitment in S. melanostictus (p < 0.05). The best fitting model was the GAM, with an AIC of 57.9 and a cumulative explanation rate of 95.7%. Sea surface temperature was the most dominant environmental factor and had a negative impact on R/S. Considering both spawning stock biomass (S) and the environmental factors in the S-R relationship is important for studying the mechanisms of complementary changes and population changes in S. melanostictus under the influence of the marine environment. Full article

Several countries and regions have regulations in place to provide standards for the welfare of production animals, which have implications for breeding, management and trade. In the chicken egg production industry, the welfare impacts of this are not well understood. In the past decades, free-range systems were widely used for local chicken breeds in poultry industry in China, but their use has gradually declined due to the lower competitiveness compared to commercial cage systems. However, the practices of free-range systems for hens raising have gradually increased again over the past decade, as consumer individualized demand for higher food quality and animal welfare has increased. We recruited 14 free-range farms and 45 cage farms from Beijing, Shandong, Hebei, Anhui, Yunnan, Gansu and Jiangsu provinces in China, for an evaluation of hen welfare, production and economic outcomes from farm operations. This study provides data for the welfare outcomes of laying hens in China and preliminarily explored the relationship between welfare level and economic income within farming system types. The researchers visited the farms and used Welfare Quality measures to investigate the welfare, and farm self-reported profits. Nonparametric Mann–Whitney U tests were used to compare the welfare scores between cage and free-range rearing farms. Correlation and regression are used for the analysis of the animal welfare scores, economic data, and production metrics. The general income from free-range farms was linearly correlated with red mite score and stocking density (p < 0.001 and p < 0.05, respectively). The results showed less centimeters of feeder and drinker space per animal in the free-range system than in cage systems (p < 0.05 and p < 0.01, respectively). Welfare scores for both the stocking density and beak condition were significantly better in the free-range systems than the cage systems (p < 0.001), as were qualitative behavior assessment scores (p < 0.05). The total egg production and peak egg production in cage farms were much higher than in free-range farms (p < 0.001), and egg loss rate was significantly lower (p < 0.001). While the production efficiency of free-range farms was lower than that of cage farms, general income per 10,000 hens was actually higher. Our results provide some evidence that some welfare indicators and general income (per 10,000 hens) in free-range farms in China were better than those of cage farms. The results indicate that better parasite control and lower stocking densities may result in improved hen welfare on free-range farms and potentially improve profitability. The level of welfare and economic benefits of free-range farms vary widely, and there was potential room for improvement in feeding space, drinking water space and human–animal relationship. Full article

The quantitative evaluation of restocking and stock replenishment is essential for providing operational feedback and implementing adaptive management for future restoration projects. Since 2010, approximately 700 million juvenile shrimp (Penaeus penicillatus) have been released into Xiamen Bay, Fujian Province, China, each year, through stock replenishment programs. The recruited shrimp were sampled through three-year bottom trawl surveys from 2014 to 2017. The biological characteristics and catch equation were used to evaluate the effect of restocking and stock replenishment. The analysis uses the FAO-ICLARM Stock Assessment Tool (FISAT II) program. In general, there are two sources of recruitments—one from spawning brood stock and the other from released juvenile shrimp. We constructed an evaluation model for an effect evaluation based on Baranov’s catch equation to separate the initial recruitment volume using survey data. The relationship between body weight and total length was W = 1.638 TL^2.9307. There is no statistically significant difference between males and females. The von Bertalanffy growth parameters derived for prawns, using FiSAT II, were L_∞ = 209.6 mm and K = 0.51 per year. In spring 2014, the initial resource amount was 49,200, while the ratio of effective recruitment and parent amount was 3.92. The survival rate of the released shrimp larvae, 1.88‱, seems to be very unsatisfactory. The resource amount in summer and autumn is higher than in winter and spring. Obviously, the restocking effect is lower and the programs need to be improved. To improve the restocking effect, the replenishment performance should be adjusted to reduce the mortality rate and increase its release effectiveness. Therefore, corresponding implementations are recommended, including standard extensive culture, reduction in stress during transportation, and temporary culture. Full article

Throughout the Trump administration, media coverage of extremist factions of the American right grew considerably, as did the actual membership and numbers of those factions. Included among these factions, and operating on a spectrum that ranges from the center-to-fringe right, are white supremacist, Christian nationalist, and militia/patriot/sovereign citizen (broadly termed constitutionalist) movements. While the American right is heterogeneous, most of these groups are composed of white men, and male supremacism is often a common ideological denominator. Based on historical trends, recent activity, and ongoing movement mobilizations, we should anticipate increased recruitment and activism on the part of anti-statist right-wing groups during the Biden administration. While much has been written about the threat of terroristic violence these groups pose and their varying levels of engagement with white supremacist beliefs, examinations of gender have largely focused on masculinity. This note takes up the relationship between anti-statist right-wing movements and women by sketching three key areas that warrant further examination: (1) how collective interpretations of the law leave women vulnerable by refusing the legitimacy of federal legislation; (2) the threat of militia violence against women, particularly those who hold elected office; (3) how racial and gender exclusions preclude women from having their claims to membership in anti-statist right-wing movements be fully recognized. As we take stock of the growing threat posed by these movements, it is incumbent on us to critically examine the threats to women’s rights posed by the anti-statist right. Full article

Freshwater mussels, Unionoida, are endangered across the globe due to recruitment failure. In the present study, with general linear mixed models, we investigated the relative effects of biotic (host fish density) and abiotic (water depth, fine sediment, water temperature, and water quality) factors on the recruitment of Margaritifera laevis in 10 streams of Hokkaido, northern Japan. We additionally examined the factors regulating the density of the host fish Oncorhynchus masou masou with general linear models. The proportion of juvenile mussels had a unimodal relationship with the host density, which was the most influential factor among the others examined. The positive relationship between mussel recruitment and host density can be attributed to an increased host fish infection rate. The negative correlation between mussel recruitment and host density at high fish densities may be due to reduced larval growth on host fish that are in poor physical condition. We also found that host fish density was negatively affected by nutrient enrichment. Our results suggest that mitigating water quality degradation to recover host fish density should be prioritized to improve mussel recruitment. Although stock enhancement is effective for increasing the salmon population density, excess stocking can further disturb mussel recruitment. Full article

Fitting length data in age-structured stock assessment is a common method for evaluating hard-to-age animals, such as crustaceans. Growth specification and the uncertainty in the stock recruitment relationship are key issues in length-based assessment models. We conducted sensitivity analyses to evaluate the impact of growth and recruitment parameters on the stock assessment and management variables of the yellow squat lobster (Cervimunida johni) caught off the Chilean coast. Nine different scenarios of the length at first capture ( $L_{a=1}$ ) and the coefficient of variation at age ( $c{v}_a$ ) were tested for six combinations of values for the steepness parameter (h) and the recruitment variance ( ${\sigma }_R^2$ ). We also investigated the reliability of these estimates using an operating model. Our findings indicate that the parameter related to growth, $L_{a=1}$ , has the greatest impact on the assessment and management variables of this fishery resource, with $c{v}_a$ having a lesser effect. Recruitment and fishing mortality estimates were the main variables affected. Parameters h and ${\sigma }_R^2$ did not profoundly impact the variables assessed. In addition, $L_{a=1}$ was the most biased estimated parameter. We discuss that the high influence of growth parameters is related to model structure, and thus implications for determination of the status of yellow squat lobster should be addressed in the future. We recommended developing simulation protocols for the selection of growth parameters when using an age-structured model with length observations, and we believe that our findings are relevant for all Chilean fisheries with a similar stock assessment framework. Full article