Harvest Density Research Articles

Patterns of Wolf Dispersal Respond to Harvest Density across an Island Complex.

Wolves are highly mobile predators and can disperse across a variety of habitats and over long distances. However, less is known about dispersal capabilities across water and among islands. The biogeography of island systems fosters spatially structured local populations, and their degree of connectivity may influence the dynamics and long-term viability of the regional population. We sought to quantify wolf dispersal rate, distance, and dispersal sex bias throughout Prince of Wales Island, a 6670 km2 island in southeast Alaska, and the surrounding islands that constitute the wildlife management unit (9025 km2). We also investigated patterns of dispersal in relation to hunting and trapping intensity and wolf population density. We used DNA data collected during 2012-2021 long-term monitoring efforts and genotyped 811 wolves, 144 of which (18%) were dispersers. Annual dispersal rates were 9-23% and had a weakly positive relationship with wolf density. Wolves dispersed 41.9 km on average (SD = 23.7 km), and males and females did not disperse at different rates. Of the dispersing wolves, 107 died, and the majority (n = 81) died before they were able to settle. The leading manner of death was trapping (97% of mortalities), and wolves tended to disperse from areas with low harvest density to areas where harvest density was relatively higher. Dispersal occurred both to and from small islands and the larger Prince of Wales Island, indicating bidirectional as opposed to asymmetrical movement, and the genetic overlap of wolf groups demonstrates connectivity throughout this naturally patchy system. Island ecosystems have different predator-prey dynamics and recolonization processes than large, intact systems due to their isolation and restricted sizes; thus, a better understanding of the degree of population connectivity including dispersal patterns among islands in the Prince of Wales archipelago could help inform the management and research strategies of these wolves.

Field testing of a physical impact mill in the Canadian Prairies

Herbicide resistance in western Canada has increased interest in alternative weed management strategies. Physical impact mills, a form of harvest weed seed control, have been identified as a strategy that may be well suited for Canadian use. The efficacy of the Harrington Seed Destructor, a physical impact mill, was evaluated in 20 producer fields in Alberta on a wide spectrum of weed species over 3 years. Significant differences in weed densities between the physical impact mill treatment and the regular harvest densities were few; however, some population density reductions were observed. Measurable reductions in weed densities may have been limited by the short timeframe of the experiment, the high initial densities of the weeds, or the targeted weed species having dormancy or longer term seedbanks. Additionally, identified knowledge gaps on how best to optimize physical impact mill efficacy may have reduced the efficacy of the physical impact mill in this study. This study showed no conclusive evidence for the efficacy of a physical impact mill on tested weed species under field conditions. However, it did provide a number of important considerations for future studies.

Full-thickness skin columns: A method to reduce healing time and donor site morbidity in deep partial-thickness burns.

The current standard of care for the coverage of large wounds often involves split thickness skin grafts (STSGs) which have numerous limitations. One promising technique that has gained traction is fractional autologous skin grafting using full-thickness skin columns (FTSC). Harvesting occurs orthogonally by taking numerous individual skin columns containing the epidermis down through the dermis and transferring them to the wound bed. The purpose of this porcine study was to investigate the efficacy of implanting FTSCs directly into deep partial-thickness burn wounds, as well as examining donor site healing at the maximal harvest density. It was hypothesised that by utilising FTSCs, the rate of healing in deep partial thickness burns can be improved without incurring the donor morbidity seen in other methods of skin grafting. Deep partial-thickness burns were created on the dorsum of female red duroc swine, debrided 3 days later and FTSCs were implanted at varying expansion ratios directly into the burn wounds. At day 14, 1:50 expansion ratio showed significantly faster re-epithelialisation compared to the debrided burn control and 1:200. Donor sites (at 7%-10% harvest density) were 100% re-epithelialised by day 7. Additionally, the maximal harvest density was determined to be 28% in an ex vivo model, which then five donor sites were harvested at 28% density on a red duroc swine and compared to five STSG donor sites. At maximal harvest density, FTSC donor sites were significantly less hypopigmented compared to STSGs, but no significant differences were observed in re-epithelialisation, contraction, blood flow or dermal thickness. In conclusion, implantation directly into deep partial-thickness burns is a viable option for the application of FTSCs, favouring lower expansion ratios like 1:50 or lower. Little difference in donor site morbidity was observed between FTSC at a maximal harvest density of 28% and STSGs, exceeding the optimal harvest density.

Evaluation of fish density influence on the growth of the spotted rose snapper reared in floating net cages using growth models and non-parametric tests

In commercial fish farming, growth performance is the most influential factor in economic profitability; so, biomass optimization has become a growing concern. We analyzed the influence of 3 harvest densities (15, 20, and 22 kg·m–3) on the growth of spotted rose snappers reared in floating net cages during a production cycle. To assess the impact of stocking density on growth performance, we used 2 indicators: final total length-at-age (12 months) and the growth rate estimated from growth models (von Bertalanffy, logistic, and Gompertz). For the first indicator, we tested for normality. We did the Kruskal–Wallis and the post hoc Kruskal–Wallis tests to compare the mean total final length from each density. Accordingly, the means of densities D15 and D20 were the same (P value = 0.22). For the second indicator, we fitted the models with the subroutine optim of the R statistical package using the L-BFGS-B algorithm. Model selection was made with the Akaike and the Bayesian information criteria. Both criteria suggested that the logistic model fitted the data best. With the best model (logistic), we did 1,000 bootstrap simulations for each density scenario to determine the distribution of the maximum likelihood estimation for the instantaneous growth rate. Because the estimates were normally distributed, we used ANOVA to test the equality of the instantaneous growth. The Tukey HSD test suggested that all means were statistically different from each other. The fastest growth rate (K = 0.275) corresponded to the cage with a density of 20 kg·m–3. These findings demonstrate that the logistic model can predict the growth of spotted rose snappers under culture conditions using floating net cages. These results strengthen the productive potential and economic profitability of snapper aquaculture using floating cage and may help the start of commercial scale aquaculture.

Lead exposure in American black bears increases with age and big game harvest density

Hunting has multiple consequences for wildlife, and it can be an important source of environmental pollution. Most big game hunters use lead (Pb) ammunition that shed metal fragments in the tissues of harvested animals. These Pb fragments become available to scavengers when hunters discard contaminated slaughter remains in the environment. This exposure route has been extensively studied in avian scavengers, but few studies have investigated Pb exposure from ammunition in mammals. Mammalian scavengers, including American black bears (Ursus americanus), frequently use slaughter remains discarded by hunters. The objective of this study was to investigate whether big game harvest density influenced long-term Pb exposure in American black bears from Quebec, Canada. Our results showed that female black bears had higher tooth Pb concentrations in areas with higher big game harvest densities, but such relationship was not evident in males. We also showed that older bears had higher tooth Pb concentrations compared to younger ones. Overall, our study showed that Pb exposure increases with age in black bears and that some of that Pb likely comes from bullet fragments embedded in slaughter remains discarded by hunters. These results suggest that hunters may drive mammalian scavengers into an evolutionary trap, whereby the long-term benefits of consuming slaughter remains could be negated due to increased Pb exposure.

Factors affecting age at primiparity in black bears

AbstractEffective wildlife management requires an understanding of the factors affecting population vital rates. Age at primiparity can be an important determinant of population growth rates. Thus, understanding the factors influencing age at primiparity in wild populations is important for their management and conservation. American black bears (Ursus americanus) are widely distributed in North America and show considerable variation in age at primiparity across their range. We tested hypotheses regarding top‐down and bottom‐up drivers of age at primiparity in black bears across the province of Ontario, Canada. We obtained estimates of age at primiparity using cementum patterns in 1,033 bear teeth collected as part of regulated harvest in 2018 and 2019. We compared mean ages at primiparity between 2 distinct forest regions in Ontario using a Wilcoxon test. To quantify the effects of multiple putative drivers of variation in primiparity (e.g., harvest density, food availability, land use, climate), we paired yearly probability of primiparity data with environmental covariates in a mixed effects logistic regression model. Age at primiparity was significantly lower in the more productive forest region, likely reflecting broad‐scale patterns of food availability. Further, there was a significant positive effect of growing degree days (annual sum of daily mean degrees >5°C) on probability of primiparity, likely related to its influence on ecosystem productivity. Harvest density was negatively related to the probability of primiparity, possibly because harvest is positively correlated with bear density at this broad scale, and competition for food resources increases with bear density. Overall, temporal variation in food availability had a positive effect on probability of primiparity in a model fit to data for which we had the highest confidence in age estimates from cementum. Mean age at primiparity was older (5.57 yr) than in other more southernly populations, and most harvested bears (53%) were harvested prior to reproducing. Our analysis suggests that black bear age at primiparity is primarily driven by bottom‐up forces related to climate and vegetation differences that lead to greater food availability in the south. The relatively old age at primiparity and high apparent mortality rate of young animals in this population suggests that harvest can limit recruitment substantially, which needs to be considered when making management decisions.

Digital Accounting Application in Oil Palm Plantation in Indonesia

This study is a case study conducted in an Indonesian oil palm plantation company. The study aims to understand the digital accounting application in oil palm plantations. The company has changed its recording systems in the plantation area from manual systems using paper to digital systems using applications and gadgets. This study reveals that the company is committed to applying digital accounting systems and, as much as possible, will do paperless administration in the plantation area. The analysis method is descriptive research, namely by collecting and interpreting the data obtained to provide information.
 In this study, we observe digital technology's use on a palm oil plantation, fingerprint technology for attendance on a palm oil plantation that is directly integrated with the existing payroll system. It is also integrated with the ERP system that is for recorded labors' attendance and calculates their wages and premiums. It helps the company to make faster, efficient, and more accurate reports. There is also the use of Mobile Harvesting System to record harvest density figures, the yield being harvested, and replicate tools to connect and communicate with the ERP systems. Therefore, using digital technology in plantations for accounting and other purposes much helps accelerate the data collection process. Its accuracy also helps to eliminate fraud effectively, efficiently, and accurately.

Evaluating a Three-Fold Continuum of Fry Stocking Density for Rearing Walleye in Lined Ponds

Fry stocking density can affect harvest metrics for fingerling walleye (Stizostedion vitreum) reared in drainable ponds, but few studies have examined these relationships with the use of elevated walleye fry stocking densities in lined ponds. Correlation and regression analyses were used to assess how a three-fold change in walleye fry stocking density (234,375 to 703,125 per hectare) relates to harvest metrics and length of the culture period, as well as the tradeoff experienced between walleye size (grams) and harvest density in 0.32-hectare lined ponds over a nine-year period at Blue Dog State Fish Hatchery, South Dakota. As fry stocking density increased, so did harvest metrics for both number (r = 0.85, P P -0.66, P The linear relationship between harvest density and yield was highly correlated (r = 0.95, P P 0.01) and exhibited a decreasing curvilinear relationship such that continued increases in harvest density resulted in smaller reductions in fish size. Increasing fry stocking density from 234,375 to 703,125 per hectare in lined ponds coincided with increased rearing efficiencies for number and yield, as well as a reduced culture period. Minimal reduction in walleye size occurred once harvest density exceeded 300,000 per hectare.

Implementation of technology 4.0 in achieving the effectivity and efficiency of the production process in palm oil plantation

Palm oil (Elaeis guineensis Jacq.) is a plantation commodity that has a role in the Indonesian economy. The area of palm oil plantations in Indonesia reaches 14,300,000 hectares with 43,000,000 tons of Crude Palm Oil (CPO) production. The implementation of technology 4.0 on palm oil production is needed not only for technology innovation, but also for effectivity and efficiency on production process. This research aims to study the efficiency of resources use and the effectivity of output achievement on palm oil production. This research was done descriptively and quantitatively using primary data, which was direct interviews with the people who works in palm oil plantations, and the secondary data was obtained from research results, plantation company's yearly report, and other literature review. The research result showed that the implementation of technology 4.0 on the recording of employee attendance register and calculation of harvest density rate (HDR) including field and fruit quality was more efficient 25-50% in use of employee and time. The implementation of technology 4.0 was also more effective in achieving output compared to the manual method. The conclusion of this research is the implementation of technology 4.0 on some production process in palm oil plantation is more effective and efficient compared to the manual method. The starting budget on implementing technology 4.0 is higher by 30% compared to the manual method, but it becomes ten times cheaper on the next maintenance cost.

KAJIAN SISTEM PANEN TERHADAP POTENSI CPO (CRUDE PALM OIL) DI AFDELING I KEBUN TANAH RAJA PT. BAKRIE SUMATERA PLANTATION, Tbk.

Harvest is one of determining factors to produce quality Fresh Fruit Bunches (FFB). Quality FFB is determining factors for Free Fatty Acids (FFA) and yield of the resulting oil. To produce good CPO potential, synergy is needed between the plantation part and the palm oil mill part. The research method used a descriptive method, namely to explain the harvest system and its relation to the quality of oil palm fruit. Observation data in the form of a harvest system consisting of Harvest Density Number (AKP) and random system used, Analysis of palm oil potential in the form FFB Analysis and CPO Yield. The Results showed that the harvesting system in division 1 Tanah Raja PT BSP used fixed sleigh and the potency test of palm oil showed that the CPO yield was 21.22% and FFA was 2,42%.

Experimental testing of density- and season-dependent growth in vegetative Fucus aquaculture and modelling of growth over one year for different cultivation scenarios

In the Kiel Fjord, western Baltic Sea, an experimental culture of Fucus vesiculosus and Fucus serratus has been established in order to develop a sustainable method for biomass production of these species. The cultivation method includes the unattached rearing of fronds in drifting baskets and their vegetative reproduction by cutting of small vegetative apices. In this study, we performed culture experiments to measure growth rates with this method at different initial stocking densities (1–5 kg m−2) and during different seasons of the year. Using the results, we modelled growth over 1 year for different cultivation scenarios (different initial stocking densities (1–4.75 kg m−2) and harvest densities (1.25–5 kg m−2)) in order to identify optimal scenarios and estimate annual yields and the number of necessary harvests in these scenarios. Fucus vesiculosus showed a parabolic yield–density relationship with decreasing yields at high initial stocking densities (> 2.5 kg m−2). In contrast, F. serratus showed an asymptotic yield–density relationship with rather constant yields at high initial stocking densities. Both species showed a typical seasonal growth pattern with low growth rates during winter and high growth rates during summer; however, F. serratus seemed to be growth limited during summer which was not observed for F. vesiculosus. The modelling results reflected the results of the Density experiment: for F. vesiculosus, optimal cultivation scenarios were found for intermediate cultivation densities (initial stocking densities, 1.75–2.25 kg m−2; harvest densities, 3–4 kg m−2); for F. serratus, optimal cultivation scenarios included higher densities (initial stocking densities, 2.5–4 kg m−2; harvest density, 5 kg m−2). The model scenarios predicted maximal annual yields of 6.65–6.76 kg m−2 for F. vesiculosus and 6.88–6.99 kg m−2 for F. serratus. For both species, the number of harvests necessary to achieve these yields varied depending on the cultivation scenario from 2 to 6. Scenarios with only 1 harvest per year yielded slightly lower annual yields. We conclude that the modelling results offer a valid and helpful orientation for future efforts to produce Fucus species in commercial culture.

Using Creel Data to Evaluate Blue and Channel Catfish Aggregate Harvest Regulations for Texas Reservoirs

AbstractThe Texas Parks and Wildlife Department’s strategic management plan for catfishes (Ictaluridae) called for the development of alternative harvest regulations for Blue Catfish Ictalurus furcatus and Channel Catfish I. punctatus. Angler harvest of these species in most Texas reservoirs has been regulated using a 305‐mm minimum length limit (MLL) and a 25‐fish aggregate daily bag limit (DBL) since 1995. Using existing creel data collected in 2003–2018 at 86 Texas reservoirs managed under this statewide harvest regulation, we examined Blue and Channel Catfish harvest size structure and composition, percent release of legally harvestable‐size fish, and harvest density (number and biomass). Additionally, for reservoirs having long‐term creel data, we evaluated temporal change in percent release of legally harvestable‐size fish and harvest size structure, and we estimated the impact of alternative harvest regulations by using a theoretical harvest reduction (THR) model. Channel Catfish were the predominant species harvested (>75% of harvest) in 63% of the reservoirs. Harvest size structures of Blue and Channel catfish differed, but the difference in percent harvest of fish smaller than 406 mm was negligible (52% and 48%, respectively). Percent release of legally harvestable‐size fish (≥305 mm) was low at most reservoirs (median = 13%). Total number of catfish harvested per hectare per quarter (HHQ) ranged widely (0.0–11.3) but was less than 1.0 at 58% of reservoirs. Harvest size structure was truncated over time coincident with a high harvest level (HHQ > 3.0) at two of four reservoirs with long‐term data, suggesting growth overfishing. The THR model revealed that increases in MLL resulted in variable harvest reductions among reservoirs and that removal of the 305‐mm MLL could increase harvest by 6–39%. Additionally, we found that length‐graduated DBLs would have a negligible impact on reducing the harvest of larger fish. We suggest that MLLs are not necessary for most Texas catfish fisheries and that a 356‐mm MLL may be appropriate for high‐harvest fisheries.

137 Maximal Harvest Density of Full-Thickness Skin Columns in Skin Replacement Therapy

Abstract Introduction Split-thickness skin grafts (STSGs) are the mainstay of skin replacement therapy but fail to adequately reproduce basic skin functions and subject patients to new, open wounds that can cause significant pain and scarring. Full-thickness skin grafts (FTSGs) have improved cosmetic outcomes and better recapitulate skin functions, but few sites can serve as donors and requirement for “take” is greater. Prior research has shown that full-thickness skin column (FTSC) harvest results in improved healing of the injured site and decreased morbidity of the donor site at 10% harvest density. This study aims to determine the maximal harvest density of FTSC donor sites. Methods Ten donor sites were created on the dorsum of anesthetized swine (Sus scrofa domestica). STSG donor sites were harvested with a dermatome (12/1000 inch) and compared to FTSC donor sites with the highest possible harvest ratio of sixteen 1.5mm-diameter skin columns/1cm2 (28% harvest density). Donor site morbidity was assessed via re-epithelialization, contraction, pigmentation, number of hair follicles, and scar thickness on post-burn day (PBD) 7, 14, 21, 28, 60, and 90. Results There were no significant differences in re-epithelialization or contraction between FTSC and STSG donor sites. STSG donor site pigmentation was significantly decreased as compared to control on all assessment days (p=0.0161, 0.0003, 0.0031, 0.0095, 0.0244, respectively), and remained significantly hypopigmented as compared to FTSC starting at PBD 14 (p< 0.0001). Pigmentation was decreased for FTSC donor sites at PBD 14 (p=0.0204) but significance was lost by PBD 21. Both FTSC and STSG donor sites showed significantly fewer hair follicles as compared to control at PBD 7 (p=0.0011, 0.0003, respectively). On PBD 21, STSG had significantly less hair follicles as compared to FTSC donor sites (p=0.0010). This resolved by PBD 28. FTSC scars were significantly thicker than both control and STSG at PBD 28 (p=0.0348, 0.0038, respectively) and PBD 60 (p=0.0174, 0.0329, respectively). This significance was lost by PBD 90. Conclusions No statistically significant differences were seen in re-epithelialization and contraction between FTSC and STSG donor sites. STSG were hypopigmented as compared to FTSC donor sites and had significantly less hair follicles at day 21. FTSC donor site scars were significantly thicker than STSG. Although decreased donor site morbidity has been observed at lower harvest densities (10%), these results were not seen at 28%, which likely exceeds the optimal harvest density.

Pond Substrate Type Affects Yellow Perch Fingerling Size at Harvest

Fish size and harvest density generally exhibit a negative relationship in pond culture, but the influence that pond substrate type can have on this relationship is not well understood. To evaluate the influence of pond substrate type on yellow perch (Perca flavescens), harvest density (number/hectare) was linearly regressed against individual fingerling size (grams) for lined (n = 48) and earthen (n = 40) substrate ponds that were treated similarly in terms of organic fertilizer use and the number of days in the pond over 12 culture seasons at Blue Dog Lake State Hatchery, South Dakota, USA. Harvest density explained 45 and 39% of the variation in yellow perch size in lined and earthen-substrate ponds (all P P = 0.62); however, fingerling size was significantly larger in lined ponds regardless of density that varied from near 0 to 700,000 per hectare (y-intercept comparison, P < 0.01). At the same harvest density, lined ponds will tend to produce larger yellow perch fingerlings compared to earthen ponds when similar organic fertilizers are used.

Impact of a recolonizing, cross-border carnivore population on ungulate harvest in Scandinavia

Predation from large carnivores and human harvest are the two main mortality factors affecting the dynamics of many ungulate populations. We examined long-term moose (Alces alces) harvest data from two countries that share cross-border populations of wolves (Canis lupus) and their main prey moose. We tested how a spatial gradient of increasing wolf territory density affected moose harvest density and age and sex composition of the harvested animals (n = 549,310), along a latitudinal gradient during 1995–2017. In areas containing average-sized wolf territories, harvest density was on average 37% (Norway) and 51% (Sweden) lower than in areas without wolves. In Sweden, calves made up a higher proportion of the moose harvest than in Norway, and this proportion was reduced with increased wolf territory density, while it increased in Norway. The proportion of females in the adult harvest was more strongly reduced in Sweden than in Norway as a response to increased wolf territory density. Moose management in both countries performed actions aimed to increase productivity in the moose population, in order to compensate for the increased mortality caused by wolves. These management actions are empirical examples of an adaptive management in response to the return of large carnivores.

Relationships among white-tailed deer density, harvest, and landscape metrics in TN, USA

Landscape and harvest indices are frequently used to represent white-tailed deer (Odocoileus virginianus) density. However, the relationship between deer density and specific landscape indices is unclear. Harvest is another metric often used to estimate deer density. Our objective was to model the relationship among deer density, landscape metrics, and harvest density of deer in TN, USA. We estimated deer density across 11 regions in 2011 using distance sampling techniques. We developed 18 a priori models to assess relationships among deer density, harvest density, and landscape metrics. Estimates of deer density ranged from 1.85 to 19.99 deer/km2. Deer density was best predicted by harvest density and harvest density + percent woody area. However, harvest density was the only important variable in predicting deer density (Σωi = 0.700). Results of this study emphasize the significance of harvest density in deer management. While the importance of harvest as a management tool for deer is likely to increase as landscapes are fragmented and urbanized, specific management guidelines should be based upon deer densities and landscape metrics when they are important.

A Flexible Model‐based Approach to Delineate Wildlife Management Units

ABSTRACTDelineation of management units for harvested wildlife should strive to maximize homogeneity within each unit subject to constraints imposed by geography and heterogeneity in factors related to human‐caused changes in vital rates. Prior efforts to delineate management units for white‐tailed deer (Odocoileus virginianus) used regression to identify environmental and sociological factors related to female harvest density, followed by spatially constrained cluster analysis to select multicounty units for management purposes. We used county‐level data in Indiana, USA, from 2012 to 2017 to present a modified approach that 1) simultaneously models variation in 4 types of human‐mediated deer mortality with spatial, environmental, and socio‐cultural explanatory variables; 2) clusters counties using a partial contiguity constraint that explicitly considers nonspatial variables; and 3) relies on expert opinion to assess model adequacy and suggest improvements. Multivariate negative binomial regression of mortality from 4 sources (legal antlerless and antlered harvest, reported deer–vehicle collisions, crop depredation permits) yielded additive models with adequate fit and sizable effects for all univariate models due to latitude (standardized coefficient, β range = −0.18–0.24), and the nonspatial variables deer habitat (β range = 0.26–1.02) and hunter density (β range = 0.25–1.02). Fraction of cropland enrolled in the Conservation Reserve Program was positively related to harvest (β range = 0.10–0.13), and general human development was positively related to deer collision deaths (β range = 0.25–0.28) and take with depredation permits (β range = 0.07–0.24). Clustering counties with partial contiguity increased within‐unit nonspatial homogeneity 1.7–1.9 times more than clustering with strict contiguity. Responses to online surveys by 10 agency biologists and conservation officers provided congruence (mean ± SD = 85.2 ± 3.4%) of expert and model‐derived maps and useful suggestions for incorporating a separate urban management unit. Combining mortality‐based statistical models and expert assessment offers a rigorous yet flexible approach to delineating spatial units for wildlife management that is easily adaptable for various harvested species in multiple jurisdictions. © 2020 The Wildlife Society.

Lifetime Sex‐Specific Moose Mortality During an Intentional Population Reduction

ABSTRACTWhere elevated harvest of ungulates is a priority, managers benefit by understanding how various sources of mortality affect the age and sex structure and trend of ungulate populations. Prior studies reported a long period (1997–2014) of moose (Alces alces gigas) nutritional stress from overabundance in our study area, an intentional 31% reduction in moose numbers using liberal harvests of females (2004–2012), and low bear (Ursus spp.) predation and high moose harvest densities relative to other largely roadless systems with moose, bears, and wolves (Canis lupus). In this paper, we detailed management findings after describing causes and rates of mortality from 226 female and 164 male moose radio‐collared at 9 months of age (1997–2008) and followed through life (1997–2019) and throughout the population reduction. We listened for mortality signals on radio‐collars 1–2 times/month when snow cover was complete and 2–4 times/month when snow cover was incomplete. Upon hearing a mortality signal, we investigated mortality sites usually within 24 hours via helicopter. Excluding hunter‐caused mortality, we estimated 28% annual mortality for male yearlings versus 17% for female yearlings, then low annual mortality rates (0–4%) to 84 months of age for males and 96 months of age for females, and gradually increasing annual mortality rates thereafter. Most (83%) male moose ≥24 months of age died from hunters; minor causes included wolves (8%), malnutrition or disease (5%), grizzly bears (U. arctos; 2%), and accidents (2%). Most female moose ≥24 months of age died from wolves (37%) or hunters (33%); minor causes included malnutrition or disease (15%), grizzly bears (10%), and accidents (5%). The proportion of radio‐collared females killed by hunters varied depending on numbers of permits issued to hunters; the kill rate of females ≥24 months of age was 58% during the initial 4 years of the 9‐year reduction, moderated at 29% during the final 5 years of the reduction, and was only 7% for all other study years. We attributed 32% of hunter kills to illegal harvest and unrecovered hunter kills. Hunters played a key role in the intentional population reduction by harvesting prime‐age and near prime‐age male and female moose that rarely died from other sources of mortality compared with calf, yearling, and older moose. Restricting general season hunters to primarily harvesting prime‐age and older male moose with antler spreads ≥127 cm did not appreciably reduce harvest of adult males. Male moose 2.0–5.3 years of age rarely died from non‐hunter causes and were largely harvested at older, prime ages (5.3–8.3 yr of age). Yearling moose of both sexes died primarily from wolves, with wolves selecting more for males. By using liberal harvests of female moose to reduce the population, managers improved moose nutrition and reproduction, met mandates for elevated harvests, and may have avoided a reoccurrence of a previous precipitous decline in moose numbers that was initiated by overabundance and extreme snow depths. © 2019 The Wildlife Society.

Methods and Process Optimization for Large-Scale CAR T Expansion Using the G-Rex Cell Culture Platform.

The G-Rex cell culture platform is based on a gas-permeable membrane technology that provides numerous advantages over other systems. Conventional bioreactor platform technologies developed for large scale mammalian cell expansion are typically constrained by the mechanics of delivering oxygen to an expanding cell population. These systems often utilize complex mechanisms to enhance oxygen delivery, such as stirring, rocking, or perfusion, which adds to expense and increases their overall risk of failure. On the other hand, G-Rex gas-permeable membrane-based bioreactors provide a more physiologic environment and avoid the risk and cost associated with more complex systems. The result is a more robust, interacting cell population established through unlimited oxygen and nutrients that are available on demand. By removing the need to actively deliver oxygen, these bioreactors can hold larger medium volumes (more nutrients) which allows the cells to reach a maximum density without complexity or need for media exchange. This platform approach is scaled to meet the needs of research through commercial production with a direct, linear correlation between small and large devices. In the G-Rex platform, examples of cell expansion (9-14day duration) include; CAR-T cells, which have atypical harvest density of 20-30×106/cm2 (or 2-3×109 cells in a 100cm2 device); NK cells, which have a typical harvest density of 20-30×106/cm2 (or 2-3×109 cells in a 100cm2 device) and numerous other cell types that proliferate without the need for intervention or complex processes normally associated with large scale culture. Here we describe the methods and concepts used to optimize expansion of various cell types in the static G-Rex bioreactor platform.

A case of underestimation of density by direct line transect sampling in a hunted roe deer (Capreolus capreolus) population

Ungulate population estimates from direct line transect counts are sometimes considered unreliable, but the causes and the degree of potential biases are often unknown. In this study, we compare population estimates of roe deer Capreolus capreolus from line transect data with those from camera traps and harvest statistics. Using a systematic line transect sampling approach, we walked 22 transects covering 1026 km2 in Central Germany (198 km survey effort). We also used random encounter modelling (REM) to estimate roe deer populations from data collected with 20 camera traps which were primarily installed to assess a recently established population of lynx Lynx lynx. From line transect data, the density of roe deer was estimated at 2.7 individuals per km2 (95% confidence interval CI, 1.4–5.4). Using camera trap data, REM estimated much higher roe deer densities, which ranged from 14.6 (CI 6.8–24.5) to 19.4 (CI 8.7–36.2) individuals per km2. Estimates obtained from camera trap data and REM are consistent with harvest statistics and density estimates from other European forest landscapes. Moreover, a careful examination of the detection probability plot from line transect data suggests that evasive movement of roe deer could have biased density estimates derived from the line transect survey. In our case study, this bias could have led to an underestimation in the hunted roe deer population in the range of 81 to 86%.