Male Density Research Articles

Endocrine, metabolic and apical effects of in utero and lactational exposure to non-dioxin-like 2,2′,3,4,4′,5,5′-heptachlorobiphenyl (PCB 180): A postnatal follow-up study in rats

PCB 180 is a persistent and abundant non-dioxin-like PCB (NDL-PCB). We determined the developmental toxicity profile of ultrapure PCB 180 in developing offspring following in utero and lactational exposure with the focus on endocrine, metabolic and retinoid system alterations. Pregnant rats were given total doses of 0, 10, 30, 100, 300 or 1000 mg PCB 180/kg bw on gestational days 7−10 by oral gavage, and the offspring were sampled on postnatal days (PND) 7, 35 and 84. Decreased serum testosterone and triiodothyronine concentrations on PND 84, altered liver retinoid levels, increased liver weights and induced 7-pentoxyresorufin O-dealkylase (PROD) activity were the sensitive effects used for margin of exposure (MoE) calculations. Liver weights were increased together with induction of the metabolizing enzymes cytochrome P450 (CYP) 2B1, CYP3A1, and CYP1A1. Less sensitive effects included decreased serum estradiol and increased luteinizing hormone levels in females, decreased prostate and seminal vesicle weight and increased pituitary weight in males, increased cortical bone area and thickness of tibial diaphysis in females and decreased cortical bone mineral density in males. Developmental toxicity profiles were partly different in male and female offspring, males being more sensitive to increased liver weight, PROD induction and decreased thyroxine concentrations. MoE assessment indicated that the 95th percentile of current maternal PCB 180 concentrations do not exceed the estimated tolerable human lipid-based PCB 180 concentration. Although PCB 180 is much less potent than dioxin-like compounds, it shares several toxicological targets suggesting a potential for interactions.

Impact of Male Hypogonadism on Bone Mineral Density in Childhood Hemato-Oncologic Disease

Introduction: Patients with childhood hemato-oncologic diseases have many medical problems, not only due to disease itself, but also adverse effects of specific treatment that patients had. Osteoporosis, one of the most common side effects of the treatment, decreases quality of life when the disease progresses. Our study investigated the impact of male hypogonadism on secondary osteoporosis in childhood hemato-oncologic patients, using association between male sex hormone and bone mineral density (BMD) measured by dual energy X-ray absorptiometry (DXA). Methods: This study collected BMD score (T-score) of 52 male subjects who were diagnosed with hemato-oncologic diseases in the past (average age of 22.3 years at DXA examination). All subjects measured serum testosterone and we divided them into two subgroups according to gonadal status. The first group, called hypogondal group, was a group of subjects with serum testosterone level less than 3.5 ng/ml. The other group was classified into eugonadal group, with serum testosterone level equal or more than 3.5 ng/ml. Mean BMD score of spine and hip were presented and compared between the two groups. Furthermore, relativity with other risk factors for osteoporosis was calculated using multiple regression analysis. Results: Overall, spine BMD in the hypogondal group did not significantly differ from the eugonadal group. However, hip BMD was significantly lower in the hypogonadal group (mean difference; 0.8, p = 0.023). Furthermore, testosterone level itself showed linear correlation with BMD score in hip (p = 0.013). When other risk factors for osteoporosis were taken into account, hemato-oncologic patients treated with total body irradiation also had significantly lower hip BMD (p = 0.007) compared with non-irradiation group. Hypogonadism still remained a significant factor for decreased bone mineral density in hip (p = 0.022). Conclusions: Hemato-oncologic patients with hypogonadism or previously treated with total body irradiation are at increased risk of decreased bone mineral density in both hips. Hypogonadism alone remains independent risk factor for osteoporosis in hip. Attention of these male patient should be paid to prevent the incidence of secondary osteoporosis.

Central Feminization of Male Mice Reduces Metabolic Syndrome

Metabolic syndrome encompasses a spectrum of conditions that increases the risk for adverse cardiovascular and metabolic diseases. Sexual dimorphism is clearly established, with men more predisposed to metabolic syndrome complications than women. It is widely accepted that the female sex hormone estrogen plays a protective role in premenopausal women through peripheral as well as central nervous system (CNS) mechanisms. However, most work to date has been based on the loss of estrogen in females (e.g. menopause). Interestingly, transgender individuals receiving feminizing gender affirming therapy (i.e. estrogen) appear to be relatively protected from metabolic syndrome conditions. Furthermore: 1) CNS estrogen is critically involved in metabolic regulation; and 2) CNS estrogen receptors in several nuclei are present at the same density in males and females. Based on this, we hypothesized that central estrogen supplementation in males would rescue metabolic syndrome phenotypes. To investigate this, six week old male C57Bl/6J mice were fed a normal chow or high fat diet (HFD) for 10 wks and were then instrumented with intracerebroventricular cannulas (ICV; n=4-6). Following surgical recovery, β-Estradiol (E2;30 mg/kg/day) or saline control was administered ICV once daily over 6 days. One week of central E2 supplementation resulted in a slight, albeit significant, decrease in body weight (42± 3 vs 37±2 g, saline vs. E2, p<0.05), that was not accompanied by changes in food/water intake or energy expenditure. Upon sacrifice it was evident that estrogen supplementation significantly altered adiposity. In particular, estrogen supplementation resulted in decreases in visceral white adipose depots including abdominal (1±0.1 vs. 0.5±0.1 g, saline vs. E2, p<0.05) and epididymal fat, whereas subcutaneous inguinal and brown fat (0.18±0.02 vs. 0.15±0.02 g, saline vs. E2, p>0.05) were unchanged. Building on this, we also evaluated hepatic lipid accumulation, (i.e. non-alcoholic fatty liver disease), a liver disorder that is common in ~70% of metabolic syndrome individuals. Oil Red O staining of the liver demonstrated that, relative to control animals, one-week supplementation with E2 resulted in a clear reduction in hepatic steatosis (23.8±4.3 vs. 15.0±1.5 percent area, Saline vs E2, p=0.05). Together, these findings indicate that short-term central estrogen supplementation in males is an effective means to reduce metabolic syndrome risk factors including visceral adiposity and hepatic steatosis. Moreover, these data may help explain why premenopausal females and transgender females are relatively protected from metabolic syndrome.

Male Impact on Female Reproductive Performance of the Larval Tephritid Parasitoid Diachasmimorpha tryoni (Hymenoptera: Braconidae).

Diachasmimorpha tryoni (Cameron) (Hymenoptera: Braconidae) is a larval parasitoid that has been mass-reared for augmentative biological control against the Mediterranean fruit fly, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae) in Hawaii and other regions. To improve performance of female wasps in biological control programs, we conducted a series of experiments to investigate male wasp reproductive performance and its role in female reproductive success. The results showed that D. tryoni males remained close to the emergence (release) site following release. Males emerged earlier than females and male's capacity to inseminate females reached the highest level (inseminated 9.2 ± 0.4 females/day) on the second day after eclosion in synchronization with female emergence peak; allowing males encountering most receptive females to enhance their mating success. Mating rates under normal rearing conditions (200 pairs per cage) reached optimum 100% insemination after 5 d. However, oviposition experience prior to mating impaired female's receptivity as a percentage of inseminated females reduced to 17.5 ± 4.8%, while 70.0 ± 4.1% females without prior oviposition experience accepted mating. Mating reduced male's survivorship and the potential lifetime fecundity of females, although multiple mating increased percentage of female offspring. Overall, influence of male density on the female oviposition rate and offspring sex ratio was not detected under captive rearing conditions. These results suggest that local and early mating is important for male's reproductive success and females must be allowed to mate before they are exposed to hosts or released in the field to achieve their full reproductive potential.

Reproductive ecology and territorial behavior of Boana goiana (Anura: Hylidae), a gladiator frog from the Brazilian Cerrado

Anuran males and females adopt different reproductive and behavioral strategies in different contexts. We investigated the reproductive ecology and territorial behavior of the treefrog Boana goiana (B. Lutz, 1968) from the Brazilian Cerrado. We hypothesized that competitor density/proximity would increase the behavioral responses of B. goiana males, and that mating would be assortative. We also tested if the number of eggs correlates with female size and if there is a trade-off between clutch size and egg size. We conducted two territoriality experiments to test the effects of male size, competitor proximity and competitor density. Larger males called more in the presence of a second male. In the second experiment, the largest males emitted more calls and the distance to the nearest male increased as resident males called more. In both experiments, the number of calls was influenced by either male size or spacing between males. Some males behaved as satellites, probably to avoid fights. Our analyses indicate that females choose males with similar sizes to their own, corroborating our hypothesis of size-assortative mating. We found no relationships between female size and clutch size/volume, and between egg size and number of eggs per clutch. We also report multiple spawning for this species. The low incidence of physical combats and the spacing pattern indicate that this species relies almost solely on calls to resolve contests, which could be explained by low motivation, or simply because males avoid combats to decrease injury risks. Thus, acoustic or even multimodal communication seems crucial for social interactions of B. goiana.

Avoidant/Restrictive Food Intake Disorder (ARFID): Its Medical Complications and Their Treatment—an Emerging Area

Avoidant/restrictive food intake disorder (ARFID) is a relatively new psychiatric and eating disorder diagnosis that most often emerges in childhood. Due to ARFID’s diagnostic infancy, its medical complications are just starting to be delineated in the literature, and some are extrapolated from the medical manifestations of malnutrition in anorexia nervosa, restricting subtype (AN-R). Pediatric patients with ARFID can have a myriad of physical complaints, most commonly gastrointestinal, that prompt them to seek medical evaluation; thus, familiarity with its medical manifestations is important for all physicians. Electrolyte abnormalities may be more common in ARFID compared to patients with AN, while bradycardia has been shown to be comparatively less common. ARFID has been found to be associated with low bone density in both males and females. Addressing nutritional deficits and weight issues are paramount. Cognitive behavioral therapy for ARFID (CBT-ARFID) and several psychotropic medications have been found to be acceptable treatment modalities, but randomized controlled trials are needed. ARFID has numerous reported and theoretical medical complications due to the resulting malnutrition that can last until adulthood if left untreated.

Time‐course in attractiveness of pheromone lure on the smaller tea tortrix moth: A generalized additive mixed model approach

AbstractLong‐term pest insect monitoring in agriculture and forestry has advanced population ecology. However, the discontinuation of research materials such as pheromone lure products jeopardizes data collection continuity, which constrains the utilization of the industrial datasets in ecology. Three pheromone lures against the smaller tea tortrix moth Adoxophyes honmai Yasuda (Lepidoptera; Tortricidae) were available but one was recently discontinued. Hence, a statistical method is required to convert data among records of moths captured with different lures. We developed several generalized additive mixed models (GAMM) separating temporal fluctuation in the background male density during trapping and attenuation of lure attractiveness due to aging or air exposure after settlement. We collected multisite trap data over four moth generations. The lures in each of these were unsealed at different times before trap settlement. We used cross‐validation to select the model with the best generalization performance. The preferred GAMM had nonlinear density fluctuation terms and lure attractiveness decreased exponentially after unsealing. The attenuation rates varied among lures. A light trap dataset near the pheromone traps was a candidate for a male density predictor. Nevertheless, there was only a weak correlation between trap yields, suggesting the difficulty of data conversion between the traps differing in attraction mechanisms.

Null Controllability of a Nonlinear Age Structured Model for a Two-Sex Population

This paper is devoted to study the null controllability properties of a nonlinear age and two-sex population dynamics structured model without spatial structure. Here, the nonlinearity and the couplage are at the birth level. In this work, we consider two cases of null controllability problem. The first problem is related to the extinction of male and female subpopulation density. The second case concerns the null controllability of male or female subpopulation individuals. In both cases, if A is the maximal age, a time interval of duration A after the extinction of males or females, one must get the total extinction of the population. Our method uses first an observability inequality related to the adjoint of an auxiliary system, a null controllability of the linear auxiliary system, and after Kakutani’s fixed-point theorem.

Symbiont dynamics during the blood meal of Ixodes ricinus nymphs differ according to their sex

Ticks harbour rich and diverse microbiota and, among the microorganisms associated with them, endosymbionts are the subject of a growing interest due to their crucial role in the biology of their arthropod host. Midichloria mitochondrii is the main endosymbiont of the European tick Ixodes ricinus and is found in abundance in all I. ricinus females, while at a much lower density in males, where it is even absent in 56 % of the individuals. This endosymbiont is also known to increase in numbers after the blood meal of larvae, nymphs or females. Because of this difference in the prevalence of M. mitochondrii between the two sexes, surveying the density of these bacteria in nymphs that will become either females or males could help to understand the behaviour of Midichloria in its arthropod host. To this aim, we have set up an experimental design by building 3 groups of unfed nymphs based on their scutum and hypostome lengths. After engorgement, weighing and moulting of a subset of the nymphs, a significant difference in sex-ratio among the 3 groups was observed. In parallel, Midichloria load in individual nymphs was quantified by qPCR both before and after engorgement.No difference in either body mass or Midichloria load was observed at the unfed stage, but following engorgement, both features were significantly different between each size group.Our results demonstrate that symbiont dynamics during nymphal engorgement is different between the two sexes, resulting in a significantly higher Midichloria load in nymphs that will become females. The consequences of those findings on our understanding of the interplay between the endosymbiont and its arthropod host are discussed.

PERANCANGAN APLIKASI SENSUS PENDUDUK PADA BADAN PUSAT STATISTIK KOTA MAKASSAR BERBASIS ANDROID

Technological developments and changes in government systems are developing rapidly. Both of these lead to efforts to carry out duties, protect functions and serve the community. This encourages the government to take various adjustment steps quickly in line with the dynamics of development that occur. One of them is through a population census. The population census is an important issue that must be handled properly. The population census in this study takes population data in an area based on the number of male population, female population, ratio, and population density. The data was taken and submitted to the Makassar City Statistics Agency. Population Census is a presentation of information that has the ability to present accurate information, and helps facilitate the search for a population census data. The population census is carried out every 5 years which is carried out by census officers to carry out data collection to each resident's house, the data collection process is carried out by conventional recording and submitting it to the central statistics agency for database entry. With this application, it is expected to provide convenience to Population census officers to perform the process of inputting population data and the data is directly stored in the database without having to return to the office to input again.

Eco-evolutionary dynamics may show an irreversible regime shift, illustrated by salmonids facing climate change

The enhanced or reduced growth of juvenile masu salmon (Oncorhynchus masou masou) may result from climate changes to their environment and thus impact on the eco-evolutionary dynamics of their life-history choices. Male juveniles with status, i.e., if their body size is larger than a threshold, stay in the stream and become resident males reproducing for multiple years, while those with smaller status, i.e., their body size is below the threshold, migrate to the ocean and return to the stream one year later to reproduce only once. Since juvenile growth is suppressed by the density of resident males, the fraction of resident males may stay in equilibrium or fluctuate wildly over a 2-year period. When the threshold value evolves, the convergence stable strategy may generate either an equilibrium or large fluctuations of male residents. If environmental changes occur faster than the rate of evolutionary adaptation, the eco-evolutionary dynamics exhibit a qualitative shift in the population dynamics. We also investigated the relative assessment models, in which individual life-history choices are made based on the individual’s relative status within the juvenile population. The eco-evolutionary dynamics are very different from the absolute assessment model, demonstrating the importance of understanding the mechanisms of life history choices when predicting the impacts of climate change.

Regal Fritillary (Speyeria idalia) Sex Ratio in Tallgrass Prairie: Effects of Survey Timing and Management Regime

The regal fritillary, Speyeria idalia (Drury), was once a common inhabitant of North American grassland communities. Regal fritillary populations are commonly reported to have a male biased adult sex ratio (ASR) throughout their range. We assessed the observed ASR of regal fritillary throughout an annual flight period, investigated how the overall density of both sexes changed, and tested effects of prescribed fire, grazing and haying management treatments on male and female density. We found that regal fritillary exhibited an observed 2:1 male biased ASR across the entire emergence period. Our analysis also revealed that male density peaked earlier than female density in the flight period. Point estimates of density indicated sites that received prescribed burning at the moderate fire-return interval supported ≥1.3 times greater density of males and ≥5.6 times greater density of females versus sites burned with short and long fire-return intervals. Additionally, this effect was enhanced when combined with grazing which showed males were ≥1.9 times and females had ≥1.2 times greater point estimates of density in sites that were grazed and burned at a moderate fire-return interval versus other sites. The relatively stable status of regal fritillary within our study region suggests that a 2:1 male to female ASR may be considered the model composition of populations throughout their range. Likewise, the dynamic nature of the ASR throughout the flight period highlights the importance of conducting surveys across the flight period. Finally, these results corroborate an increasing number of research results that reveal common prairie management practices, such as prescribed fire can be applied within sites that contain regal fritillary and continue to support stable populations.

Estimating and validating koala

Context It is notoriously difficult to estimate the size of animal populations, especially for cryptic or threatened species that occur in low numbers. Recent advances with acoustic sensors make the detection of animal populations cost effective when coupled with software that can recognise species-specific calls. Aims We assess the potential for acoustic sensors to estimate koala, Phascolarctos cinereus, density, when individuals are not identified, using spatial count models. Sites were selected where previous independent estimates of density were available. Methods We established acoustic arrays at each of five sites representing different environments and densities of koalas in New South Wales. To assess reliability, we compared male koala density estimates derived from spatial count modelling to independently derived estimates for each site. Key results A total 11 312 koala bellows were verified across our five arrays. Koalas were detected at most of our sample locations (96–100% of sensors; n = 130), compared with low detection rates from rapid scat searches at trees near each sensor (scats at &lt;2% of trees searched, n = 889, except one site where scats were present at 69% of trees, n = 129). Independent estimates of koala density at our study areas varied from a minimum of 0.02 male koalas ha−1 to 0.32 ha−1. Acoustic arrays and the spatial count method yielded plausible estimates of male koala density, which, when converted to total koalas (assuming 1:1 sex ratio), were mostly equivalent to independent estimates previously derived for each site. The greatest discrepancy occurred where the acoustic estimate was larger (although within the bounds of uncertainty) than the independent mark–recapture estimate at a fragmented, high koala-density site. Conclusions Spatial count modelling of acoustic data from arrays provides plausible and reliable estimates of koala density and, importantly, associated measures of uncertainty as well as an ability to model spatial variations in density across an array. Caution is needed when applying models to higher-density populations where home ranges overlap extensively and calls are evenly spread across the array. Implications The results add to the opportunities of acoustic methods for wildlife, especially where monitoring of density requires cost-effective repeat surveys.

Disparity in bone mineral density of males and females with age

Disparity in bone mineral density of males and females with age

Disparity in bone mineral density of males and females with age

Decline in bone mass with aging leads to osteoporosis and fragility fractures. It has profound effect on the morbidity and health quality of the elderly, creating financial burden on the society. Usually, age related loss in bone mass goes undiagnosed until a fragility fracture occurs. It was observed that the bone mineral density (BMD) was found to be lesser in females compared to males in all age groups. There were significant BMD differences between males and females from age 41 yrs and above, BMD declined with age in both males and females. The maximum decline was observed in age group of 41 yrs -50 yrs compared to the control group of 20 yrs-30 yrs. The decrease in BMD was highly noticeable in females, with osteoporosis from age group 51 yrs-60 yrs. It coincides with peri-menopausal and early after menopause period. In males osteoporosis was not observed until the age of 80yrs, though osteopenia have been observed from 41 yrs onwards. There is a paramount need of awareness about detrimental effects of aging on BMD in order to bring about necessary lifestyle changes and follow therapeutic measures. This enables us to attain higher peak bone mass and maintain higher bone densities.

МОРФОФИЗИОЛОГИЧЕСКИЕ АДАПТАЦИИ АФРИКАНСКОГО СОМА К ВЫСОКИМ ПЛОТНОСТЯМ ПОСАДКИ В УЗВ

The article presents the results of research on the effect of increased planting density on the body of african catfish. Vital organs that play a fundamental role in fish metabolism were studied: heart, liver, kidneys, and spleen. Morphophysiological adaptations of the african catfish to unfavorable environmental conditions were evaluated. The results showed that an increase in planting density causes a number of negative changes in the fish body. In pools with increased planting density, the average fish mass was significantly less than in the control. The greatest slowdown of the growth rate and biomass set was observed when the planting density increased by 30%. It was established that the liver mass increased with increasing planting density, and males had significantly larger livers than females. Liver indices P and Q increased with increasing planting density in males and females and were higher the higher the planting density. Kidney mass and their P and Q indices in catfish showed that increase in planting density depresses the kidneys, causing a decrease in their mass against the increase in the P and Q indices. With increasing planting density, the absolute weight of fish spleen decreased. A study of the heart mass of the african catfish showed that with increasing planting density, the heart mass and P and Q indices increased, due to the high energy costs of survival.

Male residency of Sunda Clouded Leopard Neofelis diardi (Cuvier, 1823) (Mammalia: Carnivora: Felidae) in a peat swamp forest, Indonesian Borneo

The Sunda Clouded Leopard Neofelis diardi is the apex predator on the island of Borneo, yet little is known of its ecology. We document the length of residency of male Sunda Clouded Leopards in Central Kalimantan, Indonesian Borneo. Over 10 years, camera trap data have been obtained in the Sebangau peat swamp forest in a study area of ~ 105km2. We identified 11 individuals (eight males, one female, and two with unknown sex), from 152 notionally independent photographs. On average, males remained in the study area for 39.3 months (SE 8.3), or 3.3 years (SE 0.7), ranging from less than a month of residency up to 71 months. Females were infrequently recorded, possibly as a result of human disturbance and/or high male densities. Our results reveal that even a 10-year dataset is inadequate to answer some basic ecological questions, emphasising the importance of long-term monitoring of this species.

Sex differences in pubertal associations with fronto-accumbal white matter morphometry: Implications for understanding sensitivity to reward and punishment

Researchers have reported sex-differentiated maturation of white matter (WM) during puberty. It is not clear, however, whether such distinctions contribute to documented sex differences in sensitivity to reward and punishment during adolescence. Given the role of the orbitofrontal cortex (OFC) and nucleus accumbens (NAcc) in reward and punishment-related behaviors, we tested in a cross-sectional study whether males and females (N = 156, 89 females; ages 9–14 years) differ in the association between pubertal stage and fixel-based morphometry of WM fibers connecting the OFC and NAcc (i.e., the fronto-accumbal tract). Further, we examined whether males and females differ in associations between fronto-accumbal WM measures and self-reported sensitivity to reward and punishment. Pubertal stage was positively associated with fronto-accumbal fiber density and cross-section (FDC) in males, but not in females. Consistent with previous reports, males reported higher reward sensitivity than did females, although fronto-accumbal combined FDC was not related to reward sensitivity in either sex. Meanwhile, only males showed a negative association between fronto-accumbal tract FDC and sensitivity to punishment. Follow-up analyses revealed that fiber cross-section, but not density, was related to pubertal stage and punishment sensitivity in males, as well as to reward sensitivity in all participants. Our findings suggest there are sex differences in puberty-related maturation of the fronto-accumbal tract, and this tract is related to lower punishment sensitivity in adolescent males compared to females.

Effect of 12 months of creatine supplementation and whole-body resistance training on measures of bone, muscle and strength in older males.

The combination of creatine supplementation and resistance training (10-12 weeks) has been shown to increase bone mineral content and reduce a urinary indicator of bone resorption in older males compared with placebo. However, the longer-term effects (12 months) of creatine and resistance training on bone mineral density and bone geometric properties in older males is unknown. To assess the effects of 12 months of creatine supplementation and supervised, whole-body resistance training on bone mineral density, bone geometric properties, muscle accretion, and strength in older males. Participants were randomized to supplement with creatine (n = 18, 49-69 years, 0.1 g·kg-1·d-1) or placebo (n = 20, 49-67 years, 0.1 g·kg-1·d-1) during 12 months of supervised, whole-body resistance training. After 12 months of training, both groups experienced similar changes in bone mineral density and geometry, bone speed of sound, lean tissue and fat mass, muscle thickness, and muscle strength. There was a trend (p = 0.061) for creatine to increase the section modulus of the narrow part of the femoral neck, an indicator of bone bending strength, compared with placebo. Adverse events did not differ between creatine and placebo. Twelve months of creatine supplementation and supervised, whole-body resistance training had no greater effect on measures of bone, muscle, or strength in older males compared with placebo.

Size-at-maturity shift in a male-only fishery: factors affecting molt-type outcomes in Newfoundland and Labrador snow crab (Chionoecetes opilio)

Abstract A sex-asymmetric downward shift in size-at-terminal-molt has recently occurred in males in some portions of the Newfoundland and Labrador (NL) snow crab stock range, a first known occurrence for such processes in snow crab (Chionoecetes opilio) stocks. This study examines plausible factors promoting the shift in size-at-terminal-molt [synonymous with size-at-maturity (SaM)] including individual size, temperature, population density, and sex ratio. Analyses highlight expanse of cold water and large male density as being significant predictors of molt-type outcomes. A confluence of cold conditions and low density of large males promoted the SaM shift. In turn, the low male density was associated with recently elevated fishery exploitation rates under quota-controlled management. It remains unknown the extent to which the reduction in terminal size reflects a phenotypic vs. genotypic process. Factors affecting skip-molting in male snow crab are investigated, and we find that skip-molting occurs most frequently under extreme cold and high population density conditions. Potential complications arising from altered growth dynamics are discussed. Overall, the results advance knowledge on intraspecific competition processes within snow crab populations and inform fisheries management systems that male-only harvest strategies do not provide full protection from biological harm to aquatic resources through fishing.