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Animal conservation translocation is an important tool available to conservation biologists to address problems of isolated, declining or endangered populations. This approach includes both captive‐bred and free‐ranging origin animals, which are used to rescue genetically limited populations and re‐establish extirpated populations. Both soft and hard release protocols (the release of animals with or without acclimatization, respectively) are used in animal conservation translocation programs; however, there is no consensus on whether one has better conservation outcomes than the other.\ud Here, we analyzed data from 17 studies to measure the efficiency of both techniques for fauna conservation. Using phylogenetic meta‐analysis, we compared results from articles that used soft and hard release protocols to determine the overall effect size. In addition, we examined if the success metrics, type of environment, taxonomic group, and animal’s origin affected the outcomes of each type of translocation programs.\ud We calculated 61 effect sizes for 17 species. We found that the soft‐release protocol is approximate 40% better than the hard‐release protocol (Estimates = 0.44, CI95: 0.11 – 0.76). Soft‐release program increased success by 77% (Estimates = 0.78, CI95: 0.37 ‐ 1.19) when movement metrics were used (as compared to hard‐release) and were 41% more successful with terrestrial species.\ud In general, soft releases showed better outcomes by reducing movements away from the release site, but this was driven mostly by terrestrial reptile translocations (77% chance of success); when birds and mammals or the other success metrics were evaluated, both release techniques had similar effects. Lastly, the origin (i.e. captive or wild) of the released animals did not influence the success rate of soft‐ vs. hard‐releases.\ud Synthesis and Applications. We conducted a meta‐analysis to evaluate which is the best release protocol for success in animal conservation: soft‐ or hard‐release. Our results showed that soft‐releases are in general better than hard‐releases, especially for reptiles. Protocol outcomes were similar for birds and mammals and were not linked to the origin of the released animals. We recommend that the decision of which protocol to use needs also to consider the financial costs of the used protocol.

Ungulate species have consistently been a major focus of reintroductions to their native ranges. Bighorn sheep (Ovis canadensis) are an ecologically sensitive species, and have experienced population declines throughout their historic range; bighorn sheep inhabited the Black Hills region of South Dakota but were extirpated from the area due to anthropogenic impacts in the early 1900s. To continue to restore populations to the area, we translocated 26 bighorn sheep from Alberta, Canada to the Deadwood Region of the Black Hills. Bighorn sheep were fitted with VHF or GPS collars and monitored throughout the duration of the study (Feb 2015–Jan 2017). Our objectives were to evaluate movement patterns post-release of bighorn sheep in the translocated Deadwood bighorn sheep herd. We utilized 3 types of home-range analyses based on collar data; kernel density estimation (KDE), minimum convex polygon (MCP), and Brownian Bridge Movement Models (BBMM) were used to estimate home-ranges year 1, year 2, and for the duration of the study. Home-range size utilizing KDE (95%; $$\overline{x}$$ = 41.41 km2, SE = 10.50), minimum convex polygon (95%; $$\overline{x}$$ = 55.73 km2, SE = 15.04), and BBMM (95%; $$\overline{x}$$ = 32.95 km2, SE = 4.67) differed among methods. Year 1 home-range sizes (95% BBMM; $$\overline{x}$$ = 40.01 km2) were larger than year 2 (95% BBMM; $$\overline{x}$$ = 4.08 km2) home-range sizes. Travel distances were also larger in year 1 ( $$\overline{x}$$ = 431.80 km) than year 2 ( $$\overline{x}$$ = 368.77 km). Our results indicate that after an acclimation period, which included individual dispersal, the translocated Deadwood bighorn sheep herd settled into smaller home-ranges near the release site.

The continuing decline and loss of biodiversity has caused an increase in the use of interventionist conservation tools, such as translocation. However, many translocation attempts fail to establish viable populations, with poor release site selection often flagged as an inhibitor of success. We used species distribution models (SDMs) to predict the climate suitability of 102 release sites for amphibians, reptiles, and terrestrial insects and compared suitability predictions between successful and failed attempts. We then quantified the importance of climate suitability relative to 5 other variables frequently considered in the literature as important determinants of translocation success: number of release years, number of individuals released, life stage released, origin of the source population, and position of the release site relative to the species' range. Probability of translocation success increased as predicted climate suitability increased and this effect was the strongest among the variables we considered, accounting for 48.3% of the variation in translocation outcome. These findings should encourage greater consideration of climate suitability when selecting release sites for conservation translocations and we advocate the use of SDMs as an effective way to do this.Idoneidad Climática como Pronosticador del Fracaso de la Reubicación por Conservación Resumen La continua declinación y pérdida de la biodiversidad ha ocasionado un incremento en el uso de herramientas intervencionistas de conservación como la reubicación. Sin embargo, muchos intentos de reubicación fracasan en el establecimiento de poblaciones viables, y generalmente se identifica a la mala selección de sitios de liberación como el inhibidor del éxito. Usamos modelos de distribución de especies (MDE) para predecir la idoneidad climática de 102 sitios de liberación para anfibios, reptiles e insectos terrestres y comparamos las predicciones de idoneidad entre los intentos fallidos y los exitosos. Después cuantificamos la importancia de la idoneidad climática en relación a otras cinco variables consideradas frecuentemente en la literatura como determinantes importantes del éxito de la reubicación: el número de años de liberaciones, el número de individuos liberados, la etapa de vida durante la liberación, la fuente de la población de origen y la posición del sitio de liberación en relación a la extensión de la especie. La probabilidad del éxito de la reubicación incrementó conforme aumentó la idoneidad climática pronosticada y este efecto fue el más fuerte entre las variables que consideramos, representando el 48.3% de la variación del resultado de la reubicación. Estos hallazgos deberían promover una mayor consideración de la idoneidad climática cuando se seleccionan sitios de liberación para reubicaciones por conservación y abogamos que el uso de los MDE es un método efectivo para hacer esto.生物多样性的持续下降和丧失致使人们更加频繁地使用保护干预措施, 如迁地保护。然而, 许多迁地保护尝试并未能建立可存活的种群, 其中释放位点选择不当往往被认为是阻碍成功的因素之一。我们使用物种分布模型预测了 102 个两栖类、爬行类和陆生昆虫释放位点的气候适宜性, 并比较了成功及失败案例的适宜性预测结果。我们还量化了气候适宜性与其它五个变量相比的相对重要性, 这五个变量经常被相关研究认为是迁地保护成功与否的重要决定因素, 包括: 释放的年数, 释放的个体数目, 被释放动物的生活史阶段, 释放种群的来源, 以及释放位点相对于物种分布范围的位置。我们发现, 迁地成功的概率随着预测气候适宜性的增加而增加, 该效应在本研究考虑的变量中影响最大, 占迁地保护结果变异的 48.3% 。以上结果表明, 应在选择迁地保护释放位点时更多地考虑气候适宜性; 我们建议使用物种分布模型来有效地实现这一目标。【翻译: 胡怡思; 审校: 聂永刚】.

Connectivity of nurseries and spawning habitats for young of the year life stage is essential for successful recruitment of fish populations and therefore provides a key indicator for river restoration measures. Models for dispersal offer the potential to draw conclusions regarding restoration scenarios and to fill knowledge gaps about possible implications for fish populations. A newly developed rheoreaction‐based correlated random walk model (RCRW), in combination with a three‐dimensional numerical model and a non‐steady‐state particle tracing model, was applied for nase carp larvae (Chondrostoma nasus) before and after a restoration project on the river Danube, Austria. Spatio‐temporal patterns of dispersal of virtual larvae, attached with rheoreactive behaviour, were analysed within both scenarios. In comparison to the heavily modified river reach, the restored reach enabled a greater amount of upstream movement from the release site and showed a generally higher variability of spatio‐temporal distribution patterns. In contrast, estimated total settlement of rheoreactive larvae was substantially higher for the situation prior to the restoration measure. By comparing model results with a previously field experiment it was found that model simulations including rheoreaction as a single behaviour for navigation could not explain the whole pattern of larval dispersal. Therefore it is highly recommended for future studies to develop larval dispersal models by considering other factors (i.e., behaviour, bio‐energetics and environmental factors) of existing and future individual‐based models, which could serve as a tool to analyse the effect of restoration measures for recruitment of riverine fish populations.

This study aims to investigate the composition and Important Value Index (IVI) of the woody stands of Tchillala, a 130-ha area selected for future North-African ostriches (Struthiocameluscamelus) prerelease in the Koutous region in Niger. The forest inventory method was implemented in 42 plots of 50 m x 20 m (1000 m²) for tree-level observation, using stratified random sampling. For each woody specimen, the trunk diameter, total height and crown diameter have been recorded; thespecimens with a trunk diameter smaller than 5 cm are considered as regenerations. A total of 17 woody species distributed across 10 families have been identified and most of them belongs either to the Mimosaceae (4 species) or the Tiliaceae (3 species). The plants density, domination and frequency were used to determine the IVI: Acacia tortilis and Balanitesaegyptiaca are the species with the highest IVI(118.43 and 88.28 respectively). The woody plants condition assessment has emphasized that trees have been facing natural (uprooting) and anthropogenic (cutting, pruning) threats. Consequently, the diameter class structures within the whole woody species community of Tchilala, as well as of the Acacia tortilis and Balanitesaegyptiaca, are mainly small size trees. The results of this study inform silvicultural management actions that would benefit to the North-African ostrich’establishment in Tchilala and the data collected are considered as possible indicators for long-term monitoring of habitat.

The Sterile Insect Technique (SIT) is currently being investigated against Aedes albopictus Skuse (Diptera: Culicidae) mosquitoes in Panchvati, a village in Mauritius. As an essential step before field releases, this study investigated the effect of temperature (2 h exposure at 5, 10, 15 or 25 °C) and compaction (2000 males per 1062 or 8553 cm3) on the fitness of radio-sterilised Ae. albopictus males with the aim of optimising their transport from the mosquito-production unit to the release site in Panchvati. Temperature and compaction had no significant effect on male survival during the first fifteen days. However, when survival was assessed over twenty-five days, males stored at 25 °C had significantly higher survival rates than males stored at lower temperatures (Kaplan-Meier: P

BackgroundReproductive containment provides an opportunity to implement a staged-release strategy for genetic control of malaria vectors, in particular allowing predictions about the spread and persistence of (self-limiting) sterile and male-biased strains to be compared to outcomes before moving to (self-sustaining) gene-drive strains.MethodsIn this study, we: (i) describe a diffusion–advection–reaction model of the spread and persistence of a single cohort of male mosquitoes; (ii) elicit informative prior distributions for model parameters, for wild-type (WT) and genetically modified dominant sterile strains (DSM); (iii) estimate posterior distributions for WT strains using data from published mark-recapture-release (MRR) experiments, with inference performed through the Delayed-Rejection Adaptive Metropolis algorithm; and (iv) weight prior distributions, in order to make predictions about genetically modified strains using Bayes factors calculated for the WT strains.ResultsIf a single cohort of 5000 genetically modified dominant sterile male mosquitoes are released at the same location as previous MRR experiments with their WT counterparts, there is a 90% probability that the expected number of released mosquitoes will fall to < 1 in 10 days, and that by 12 days there will be a 99% probability that no mosquitoes will be found more than 150 m from the release location.ConclusionsSpread and persistence models should form a key component of risk assessments of novel genetic control strategies for malaria vectors. Our predictions, used in an independent risk assessment, suggest that genetically modified sterile male mosquitoes will remain within the locality of the release site, and that they will persist for a very limited amount of time. Data gathered following the release of these mosquitoes will enable us to test the accuracy of these predictions and also provide a means to update parameter distributions for genetic strains in a coherent (Bayesian) framework. We anticipate this will provide additional insights about how to conduct probabilistic risk assessments of stage-released genetically modified mosquitoes.Graphical abstract

Camels (Camelus dromedarius) are known to have good navigational abilities and can find their home after displacement to far places; however, there are no studies available on the navigational strategies employed by the camels in homing behavior. Thus, the aim of this study was to investigate these strategies by displacing female camels equipped with GPS trackers 6 km away from home to totally unfamiliar locations. The experiments comprised displacing nursing or non-nursing female camels 6 km from their living pens to an unfamiliar release site. Some camels were taken to the release site on foot, others were hauled on a truck, both during daytime and nighttime. Displacements journeys were either in a straight direction to the release points, or they consisted of a convoluted path. As a result, camels that had straight outward journeys were able to return home efficiently and rather directly, but camels that had convoluted trips to the release point failed to do so. Moreover, impairing olfactory, visual, and auditory inputs by using mouth/nose muzzles, eye covers and headphones did not affect homing ability. Based on these experiments the most likely hypothesis is that during their small-scale round trips the camels relied on path integration, and that this strategy is disrupted when the camels were subjected to disorientation procedures before release., Summary: The study reports a series of experiments aimed at understanding the orientation mechanisms of Arabian camels in the Rub' al Khali desert in the UAE. Camels were taken either on foot or inside trucks to unfamiliar release points, some 6 km from their living pens. Camels homed successfully after simple displacements but seemed lost after a looping journey. It is inferred that camels use path integration, dead reckoning, after short simple displacements.

To provide estimates of Blanding's Turtle (Emydoidae blandingii) hatchling survival and to better understand the utility of alternative management tactics targeting this age class, we monitored survival and movements after natural (caged) and artificial incubation by using radio telemetry. We found that survival was similarly high (ca. 80% over 88 days) across treatments and study locations. Movement distances were similar among treatments but differed among study locations, perhaps because of differences in release site habitat variables. Our results suggest that nest cages and artificial incubation are equally effective methods for increasing survival to hatching. Extrapolating from the 88 days of our study, until resumption of activity following hibernation, we found survival estimates of 40%–78%, depending on the survival function used. When coupled with published rates of nest survival (6%–41%) and hatch success (47%–87%), anticipated age 0 survival, from egg deposition to emergence from hibernation, ranged from 1%–28%. Although our analysis fills a knowledge gap in Blanding's Turtle demography, further study is needed to improve the precision of survival estimates.

Despite the ecological importance of long-distance dispersal in insects, its mechanistic basis is poorly understood in genetic model species, in which advanced molecular tools are readily available. One critical question is how insects interact with the wind to detect attractive odor plumes and increase their travel distance as they disperse. To gain insight into dispersal, we conducted release-and-recapture experiments in the Mojave Desert using the fruit fly, Drosophila melanogaster. We deployed chemically baited traps in a 1 km radius ring around the release site, equipped with cameras that captured the arrival times of flies as they landed. In each experiment, we released between 30,000 and 200,000 flies. By repeating the experiments under a variety of conditions, we were able to quantify the influence of wind on flies’ dispersal behavior. Our results confirm that even tiny fruit flies could disperse ∼12 km in a single flight in still air and might travel many times that distance in a moderate wind. The dispersal behavior of the flies is well explained by an agent-based model in which animals maintain a fixed body orientation relative to celestial cues, actively regulate groundspeed along their body axis, and allow the wind to advect them sideways. The model accounts for the observation that flies actively fan out in all directions in still air but are increasingly advected downwind as winds intensify. Our results suggest that dispersing insects may strike a balance between the need to cover large distances while still maintaining the chance of intercepting odor plumes from upwind sources.

Over the last two centuries, the Red-and-green Macaw (Ara chloropterus) has become locally extinct in Argentina. In an attempt to restore its key ecosystem functions as both disperser and regulator of large-seeded plants, a reintroduction project was initiated at the Iberá National Park in northeastern Argentina. The ability of released individuals to find food is crucial, in particular when working with captive-bred animals, as long-term establishment of a self-sustaining population depends on their short-term ability to exploit wild food sources. Monitoring of feeding habits is usually conducted through behavioral observation, but in recent years DNA metabarcoding has emerged as an alternative for obtaining highly resolved data on diet composition. In this study we use a combination of both techniques to characterize the breadth and composition of the reintroduced macaws’ diet. In addition, we evaluate the efficiency of both direct field observations and metabarcoding of feces as techniques to assess diet composition. Individuals fed on a variety of plant species (n = 49) belonging to a broad phylogenetic spectrum (28 families). Dietary richness estimated by direct observation and metabarcoding was similar, though smaller than the combination of the two datasets as both techniques detected at least 15 species not recorded by the other method. While the total number of detected species was higher for observational data, the rate of species-detection per sampling day was higher for metabarcoding. These results suggest that a combination of both methods is required in order to obtain the most accurate account of the total diversity of the diet of a species. The ability of the reintroduced macaws to successfully exploit local food resources throughout the year indicates a good level of adjustment to the release site, an important step towards the creation of a stable, self-sustaining population of Red-and-green Macaws in Northern Argentina.RESUMENEn el transcurso de los últimos dos siglos, el Guacamayo Rojo (Ara chloropterus) se ha extinguido en la Argentina. Buscando recuperar su rol ecológico tanto de dispersor como de depredador de semillas de gran tamaño, se comenzó un proyecto de reintroducción de la especie en el Parque Nacional Iberá, en la región noreste del país. La capacidad para encontrar alimento por parte de los individuos liberados es crucial, particularmente cuando se trabaja con animales provenientes de condiciones de cautiverio, ya que el establecimiento de una población autosuficiente a largo plazo dependerá de la habilidad de éstos para explotar fuentes de alimento silvestre a corto plazo. El monitoreo de hábitos alimenticios se realiza usualmente a través de observaciones comportamentales. Sin embargo, en los últimos años la técnica del meta-código de barras de ADN ha surgido como una alternativa para la obtención de datos de composición dietaria con alto nivel de resolución. En este estudio, utilizamos una combinación de ambas técnicas para caracterizar la amplitud y composición de la dieta de los guacamayos reintroducidos. A su vez, evaluamos la eficiencia de la observación directa y el código de barras genético de heces como técnicas para evaluar la composición de la dieta. Los individuos se alimentaron de una amplia variedad de especies (n = 49), abarcando un amplio espectro filogenético (28 familias). La riqueza dietaria estimada por observación directa y por meta-código de barras genético fue similar, aunque menor a la resultante de la combinación de todos los datos ya que ambas técnicas detectaron al menos 15 especies no registradas por el otro método. Mientras que el número total de especies detectadas fue mayor para los métodos observacionales, la tasa de detección de especies por día de muestreo fue mayor para el análisis genético. Estos resultados sugieren que una combinación de ambos métodos es necesaria para obtener la descripción más precisa posible de la diversidad dietaria total de una especie. La capacidad de los guacamayos reintroducidos para explotar recursos alimenticios locales a lo largo del año estaría indicando un buen nivel de adaptación al sitio de liberación, un paso muy importante hacia el establecimiento de una población de Guacamayo Rojo estable y autosuficiente en el norte de Argentina.Palabras claveAra chloropterus, Conservación, Dieta, Frugivoría, Meta-código de barras, Guacamayo Rojo, Reintroducción, Ecología tróficaLAY SUMMARYThe Red-and-green Macaw reintroduction project aims to restore this species to Argentina, where it is locally extinct. To assess if reintroduced macaws are successfully adapting to life in the wild, we studied their foraging habits at the Iberá National Park. Their food consumption was observed visually, and their feces were analyzed with molecular methods for traces of the consumed plants.Macaws fed from a large diversity of food items, exhibiting a flexible diet which varied with fruit availability in different months. A combination of both methods was required to obtain the most accurate account of the total diversity of the diet of a species.The reintroduced macaws were able to successfully locate and exploit food resources throughout the year, indicating a good level of adjustment to the release site.

Nervous systems are built on synaptic connections, and our understanding of these complex compartments has deepened over the past quarter century as the diverse fields of genetics, molecular biology, physiology, and biochemistry each made significant in-roads into synaptic function. On the presynaptic side, an evolutionarily conserved core fusion apparatus constructed from a handful of proteins has emerged, with Unc13 serving as a hub that coordinates nearly every aspect of synaptic transmission. This review briefly highlights recent studies on diverse aspects of Unc13 function including roles in SN RE assembly and quality control, release site building, calcium channel proximity, and short-term synaptic plasticity.

Re-introduction of Eurasian Lynx to Scotland is being considered. Work by others has provided an ecological rationale for reintroduction and trial re-introductions are proposed on the Scottish border. This paper presents an Agent Based Model which simulates the potential for individual lynx to successfully disperse from a release point, using movement rules derived from observation of wild lynx in Europe. Results suggest high mortality from road crossings could hinder effective dispersal. The model is used to suggest the strongest candidate release site based on dispersal with and without a road mortality effect. This occurs in the Galloway Forest Park. The model is built using open source tool Netlogo, the programming language is relatively straightforward and extensible so other life events and human interactions can be modelled. Movement parameters can easily be reset to explore other hypothesised movement patterns. This paper contributes to spatio-temporal understanding of lynx dispersal, via a dynamic visual representation of movement in an ABM. This may help appraise the case for re-introduction in a particular location as well as providing a discursive tool that may help to understand and resolve concerns of community stakeholders, which would aid development of suitable policies. Model code is available via online repository: https://github.com/DrIanPhilips/LynxABM.

Fishes exhibit a range of biological responses to the process of catch-and-release recreational angling. In the last decade, research has begun to consider how such fisheries interactions alter the behaviour (e.g., movement, feeding activity, reproduction) of fish upon release. In this study, we assessed reflex impairment and then affixed radio telemetry transmitters to 34 blue-finned mahseer (Tor khudree) angled on the Cauvery River, India, between February and May of 2015. We then tracked their movements over two time scales: continuously for 90 min post-release, and hourly over a 24 h period. When testing reflex impairment, mahseer were more likely to first lose orientation, followed by loss of tail grab response, then loss of regular operculum beats. Neither reflex impairment nor time taken for fish to swim away from the release site varied significantly with air exposure or handling time. Similarly, movement rates of mahseer were consistent amongst tagging periods. However, trends did indicate that larger fish subject to longer angling and handling times took longer to leave the release site, moved less during the initial release period, and moved less over a 24 h cycle. We recommend that anglers view impairment of multiple reflexes in blue-finned mahseer as an indication that caution in handling is warranted. We also recommend further study of size- and age-based differences in mahseer behaviour, including specific research on responses of trophy-sized mahseer to catch-and-release angling. Our work contributes to the understanding of sublethal behavioural consequences of catch-and-release while generating some of the first information to guide development of best practice guidelines for those catching and releasing blue-finned mahseer.

Mercury (Hg) is a global pollutant that has wide-ranging impacts on the physiological systems of birds, but almost nothing is known about how this affects migration. We manipulated methylmercury (MeHg) burdens of 24 wild-caught Yellow-rumped Warblers (Setophaga coronata) before releasing them and tracking their spring migration with automated radiotelemetry to study the effect of MeHg on stopover departure behavior and flight orientation. Dosing half the birds for 14 days prior to release resulted in environmentally relevant mean blood total Hg (THg) concentrations of 6.61 (± 0.16) p.p.m., while a group of 12 controls had nearly undetectable blood THg. We observed starkly different departure behavior between groups, with dosed birds leaving the release site significantly sooner than controls. Among birds that were detected beyond the release site, seven (three dosed, four control) initially made a landscape-scale relocation before a longer-distance migratory flight, while two (controls) migrated directly from the release site. All flights were in the seasonally appropriate direction regardless of group. Rapid departures by dosed birds could have been the result of hyperactivity that can be induced by MeHg, or due to decreased social dominance that caused them to seek areas with less resource competition. We found no evidence that MeHg impaired orientation, although sample sizes were small and we had less ability to detect birds flying in “incorrect” than northward directions. The dramatic difference in departure decisions between groups indicates a potential effect of MeHg on the neurological and/or physiological mechanisms that control migratory behaviors of birds.

Gopher Tortoise (Gopherus polyphemus) populations are declining throughout the southeastern United States. Range-wide conservation efforts include identifying populations that do not currently meet viability criteria but are suitable candidates for population enhancement. We investigated the potential role of head starting as a recovery tool by releasing hatchling and head-started yearling Gopher Tortoises as pairs (n = 28) into adult burrows in fall and comparing their movements and survival until winter dormancy. Head-started yearlings experienced higher predicted survival than did hatchlings (87.7% vs. 56.5%). Head-started individuals also tended to move greater distances between burrows and established dormancy burrows further from their release burrows, but the differences were not significant. Most individuals of both groups used a small number of closely spaced burrows, although hatchlings took longer than head-started individuals to establish their first burrow (11.3 vs. 4.4 d on average) and a higher proportion were depredated or censored before establishing a burrow (35.7% vs. 10.7%). The paired release design provides strong experimental evidence that head-started yearling Gopher Tortoises experience at least a short-term survival advantage over hatchlings, while exhibiting comparable fidelity to the release site. Soft-release pens were not necessary to promote high site fidelity in our study, but the decision as to whether or not to use them at other release sites may be dictated by the predator community and what is practical to implement. We contend that head starting shows promise as a recovery tool for Gopher Tortoises and that hard releases may be a worthwhile option for managers to consider.

The control of such human diseases as dengue, Zika, and chikungunya relies on the control of their vector, the Aedes aegypti mosquito, because there is no prevention. Control of mosquito vectors can rely on chemicals applied to the immature and adult stages, which can contribute to the mortality of non-targets and more importantly, lead to insecticide resistance in the vector. The sterile insect technique (SIT) is a method of controlling populations of pests through the release of sterilized adult males that mate with wild females to produce non-viable offspring. This paper describes the process of producing sterile males for use in an operational SIT program for the control of Aedes aegypti mosquitoes. Outlined here are the steps used in the program including rearing and maintaining a colony, separating male and female pupae, irradiating and marking adult males, and shipping Aedes aegypti males to the release site. Also discussed are procedural caveats, program limitations, and future objectives.

Eastern North American migratory monarch butterflies (Danaus plexippus) have faced sharp declines over the past two decades. Captive rearing of monarch butterflies is a popular and widely used approach for both public education and conservation. However, recent evidence suggests that captive-reared monarchs may lose their capacity to orient southward during fall migration to their Mexican overwintering sites, raising questions about the value and ethics of this activity undertaken by tens of thousands of North American citizens, educators, volunteers and conservationists each year. We raised offspring of wild-caught monarchs on swamp milkweed (Asclepias incarnata) indoors at 29°C during the day and 23°C at night (~77% RH, 18L:6D), and after eclosion, individuals were either tested in a flight simulator or radio tracked in the wild using an array of automated telemetry towers. While 26% (10/39) of monarchs tested in the flight simulator showed a weakly concentrated southward orientation, 97% (28/29) of the radio-tracked individuals that could be reliably detected by automated towers flew in a south to southeast direction from the release site and were detected at distances of up to 200 km away. Our results suggest that, although captive rearing of monarch butterflies may cause temporary disorientation, proper orientation is likely established after exposure to natural skylight cues.

More than three million farmed mallards are released annually for hunting purposes in Europe. The ecological impact of these releases depends on how many birds survive to join the wild breeding population. We estimated annual survival in farmed-released and wild-caught Swedish mallards, using mark-recapture data. In 2011–2018, we ringed 13,533 farmed ducklings before release (26.5% recovered). Most recoveries were birds shot at the release site, while only about 4% were found >3 km away. In 2002–2018, 19,820 wild mallards were ringed in Sweden, yielding 1369 (6.9%) recoveries. Like in farmed-released birds, most recoveries were by hunting, but 91.1% of recovered wild mallards were >3 km away from the ringing site. Annual survival rate in farmed-released mallards (ringed as pulli) was 0.02. In wild mallards (ringed as fledged or fully grown), annual survival was lower in females (0.64) than in males (0.71). At two sites in 2018, farmed ducklings were released in two batches 3 weeks apart to study the effect of early versus late release date, while controlling for body condition (BCI). Ducklings released early had a higher BCI and were recovered earlier (lower longevity) than those released late. Individual BCI and longevity were not correlated in recovered ducklings. Based on our estimate of annual survival in farmed-released mallards, a substantial number, i.e., 5000 (95% CI, 3040–6960), join the wild population annually. Despite being fed, a large proportion of released ducklings does not survive until the hunting season. Early releases may maximize pre-hunting survival. Repeated releases may prolong hunting opportunities and increase hunting bags.

Despite the ecological importance of long-distance dispersal in insects, its underlying mechanistic basis is poorly understood. One critical question is how insects interact with the wind to increase their travel distance as they disperse. To gain insight into dispersal using a species amenable to further investigation using genetic tools, we conducted release-and-recapture experiments in the Mojave Desert using the fruit fly,Drosophila melanogaster. We deployed chemically-baited traps in a 1 km-radius ring around the release site, equipped with machine vision systems that captured the arrival times of flies as they landed. In each experiment, we released between 30,000 and 200,000 flies. By repeating the experiments under a variety of conditions, we were able to quantify the influence of wind on flies’ dispersal behavior. Our results confirm that even tiny fruit flies could disperse ∼15 km in a single flight in still air, and might travel many times that distance in a moderate wind. The dispersal behavior of the flies is well explained by a model in which animals maintain a fixed body orientation relative to celestial cues, actively regulate groundspeed along their body axis, and allow the wind to advect them sideways. The model accounts for the observation that flies actively fan out in all directions in still air, but are increasingly advected downwind as winds intensify. In contrast, our field data do not support a Lévy flight model of dispersal, despite the fact that our experimental conditions almost perfectly match the core assumptions of that theory.Significance StatementFlying insects play a vital role in terrestrial ecosystems, and their decline over the past few decades has been implicated in a collapse of many species that depend upon them for food. By dispersing over large distances, insects transport biomass from one region to another and thus their flight behavior influences ecology on a global scale. Our experiments provide key insight into the dispersal behavior of insects, and suggest that these animals employ a single algorithm that is functionally robust in both still air and under windy conditions. Our results will make it easier to study the ecologically important phenomenon of long-distance dispersal in a genetic model organism, facilitating the identification of cellular and genetic mechanisms.

Eastern North American migratory monarch butterflies (Danaus plexippus) have faced sharp declines over the last two decades. Although captive rearing has been used as an important tool for engaging the public and supplementing conservation efforts, a recent study that tested monarchs in a flight simulator suggested that captive-reared monarchs lose their capacity to orient southward during fall migration to their Mexican overwintering sites. We raised offspring of wild-caught monarchs on swamp milkweed (Asclepias incarnata) and, after eclosion, individuals were either tested in a flight simulator or radio-tracked in the wild using array of over 100 automated telemetry towers. While only 33% (7/39) of monarchs tested in the flight simulator showed strong southeast to southwest orientation, 97% (28/29) of the radio-tracked individuals were detected by automated towers south or southeast of the release site, up to 200 km away. Our results suggest that, though captive rearing of monarch butterflies may cause temporary disorientation, proper orientation is likely re-established after exposure to natural skylight cues.

Emamectin benzoate (EB) is a prophylactic pharmaceutical used to protect Atlantic salmon (Salmo salar) smolts migrating out of rivers and into the ocean against sea lice parasites. Randomized control trials comparing the marine survival of smolts treated with EB to a control group is used to calculate the fraction of marine mortality attributable to sea lice parasitism. However, it is assumed that there is no baseline difference in survival induced by the application of EB treatment. We used a combined laboratory and field study approach to investigate the potential impacts of EB treatment on behaviour and survival of hatchery-reared Atlantic salmon in western Norway. In aquaria experiments, EB-treated salmon smolts did not differ significantly in exploratory behaviour. Fish from treated groups responded similarly to simulated predator attack with spontaneous escape and elevated gill beat rate. Three rivers in the Osterfjord system of western Norway were selected for field experiments, Dale, Vosso, and Modalen. Dale River smolts were treated with intraperitoneal EB injections and had lower probability of detection in a wolf trap downstream of the release site than control smolts. Salmon smolts raised in the Vosso River hatchery were treated with EB delivered in their food and were detected on PIT antennas at the rivermouth of Vosso and Modalen at lower rates than control fish, but only when released at downstream sites. Calculation of risk ratios suggested that the bias in mortality caused by treatment with EB decreased the estimated survival of treated fish from an expected 18%to 46%, reducing the observable negative impact of sea lice on Atlantic salmon smolts in randomized control trials. The results suggest that estimates of the fraction of mortality attributable to sea lice may be underestimated due to lower baseline survival of treated fish caused by treatment and bring urgent attention towards a potential systematic underestimation of the impacts of sea lice on wild salmon. Acceptedversion

The javan gibbon reintroduction program requires assessment of suitable habitat within release sites to assure the survival of released gibbons. We studied habitat suitability for javan gibbon beginning in April 2017, extending to June 2017 in the Mount Malabar Protected Forest (MMPF), West Java. The objectives of this study were to analyze the habitat suitability of the release site for javan gibbon in MMPF. Analysis of Geographical Information System (GIS) and Principal Component Analysis (PCA) approach were used to obtain habitat suitability values. Habitat suitability variables measured are elevation, Normalized Differential Vegetation Index (NDVI), Bareness Soil Index (BSI), distance from the road, farming, settlement, and open field. We found suitability valued areas consisting of high suitability covered 2,009.23 ha (22.31%), moderate suitability covered 2,497.46 ha (27.73%), and low suitability covered 4.499,65 ha (49.96%), from a total area ± 8.894,47 ha in MMPF.

O crescimento urbano proporciona cada vez mais uma sobreposição de áreas entre a fauna e o homem, podendo levar a interações com risco potencial de acidentes. Diante disto, este trabalho objetiva registrar os resgates e solturas de Caiman latirostris na Região Metropolitana do Recife pelos órgãos responsáveis pela fauna. Entre os anos de 2010 e 2014, foram resgatados 352 indivíduos, com informações do local de resgate em 58,3% das notificações, sendo do total 5% com informações documentadas sobre o local de soltura. O número de animais registrados apresenta correlação positiva com a pluviosidade, que explica em 67,2% na variação do número de resgates notificados no período chuvoso. No geral, as informações de resgates, soltura e as relações espaciais e temporais dos jacarés em seu hábitat deverão fornecer dados para o desenvolvimento de planos de manejo e conservação para a espécie na região estudada.

A total of 12 adult European sea bass Dicentrarchus labrax were tagged with pop-off satellite archival tags (PSAT) in Irish coastal waters and in offshore waters in the north-east Celtic Sea between 2015 and 2016. Archived data were successfully recovered from five of the 12 tags deployed, three from fish released in inshore Irish waters and two from fish released offshore in the eastern Celtic Sea. All three fish tagged in inshore waters were found to undertake migrations into the open ocean coinciding with the spawning period. These fish also exhibited fidelity to inshore sites post-migration, returning to the same general location (within c. 73 km, which is roughly the predicted mean accuracy of the method) of their original release site. Although the number of tracks obtained here was limited, some degree of aggregation between inshore and offshore tagged fish in the eastern Celtic Sea was noted during the expected spawning period suggesting PSATs can provide new information on specific spawning locations of European sea bass.

Intraspecific chemical communication among related and unrelated conspecifics may play an important role in social organization and kin recognition within snakes. We monitored the movements of 7 adult Crotalus horridus (Timber Rattlesnake) and 22 of their neonates from May 2008 to October 2010. Our objective was to determine if neonates follow their mothers to suitable den sites in North Central Missouri. Mothers tended to move away from the rookery between parturition and ingress, but neonates stayed in the vicinity of their release site for up to a week after the dispersal of their mother. Despite the loss of radiotransmitters, we were able to follow 6 neonates to ingress: 5 overwintered in the same den as their mother and 1 overwintered in a known den of a conspecific female. Our observations support the hypothesis that Timber Rattlesnake neonates follow their mother or, at the very least, follow conspecifics to suitable den sites in the ir first year.

Geomys personatus maritimus (Maritime Pocket Gopher) is a genetically distinct subspecies of pocket gopher that occurs only in deep, sandy soils located in Nueces and Kleberg counties of southern Texas. The US Fish and Wildlife Service considers it a species of concern. Pocket gophers are considered a nuisance because they dig burrows and create mounds in landscaped areas. Lethal control options are not advised because of the Maritime Pocket Gopher's rarity status and recent public attitude disfavoring lethal methods. However, short-distance translocation might be a management option, but research to determine its viability is lacking. We captured 15 Maritime Pocket Gophers from athletic fields and commercial properties in Corpus Christi, TX. For all captured gophers, we subcutaneously or intraperitoneally implanted a radio transmitter, translocated the animals to private property within 2 km from their capture site, and radio-tracked their movements for ≤4 months to determine if their behavior and activity differed from 4 control gophers. Subcutaneous transmitters implanted in the scapular region were lost by 86% of the gophers (n = 12 of 14), while 100% (n = 5) of the gophers retained intraperitoneal-implanted transmitters. Relocated Maritime Pocket Gophers did not return to their site of origin. Gopher movements generally were away from their homing lines (i.e., an imaginary line drawn between each translocated gopher's capture site and release site), and they did not become successively closer to their respective sites of capture. Therefore, short-distance translocation has the potential to be a management option for nuisance gophers.

Fishery enhancement projects can provide unanticipated research opportunities to reveal fundamental aspects of the biology of species being produced. Although Pacific salmon are well known for their abilities to migrate home to freshwaters for spawning, homing to marine release sites is not widely known or understood. For more than three decades, juvenile Chinook salmon (Oncorhynchus tshawytscha) and coho salmon (O. kisutch) have been released into and subsequently homed back as adults to a nondescript semi-natural saltwater lagoon in Homer, Alaska, supporting a popular sport fishery. Through a case study of the fishery enhancement project at the “Homer Spit Fishing Hole”, also known as the Nick Dudiak Fishing Lagoon (NDFL), we illustrate a rare example of homing to marine release sites by Pacific salmon. Our goals are to briefly review the history of the NDFL sport fishery and provide evidence of homing through patterns of release, angler harvest, and coded-wire tag recoveries. We discuss the potential for olfactory imprinting to marine-derived environmental cues in conjunction with geomagnetic imprinting and navigation that may be underpinning the ability for adult salmon to home to this marine release site. Although the proximate factors that allow homing to the NDFL remain unclear, we suggest that this peculiar fishery represents a serendipitous opportunity to explore patterns of migration, imprinting, and homing by Pacific salmon.

Initial movements of re- introduced wildlife populations can determine short-term restoration success. Managers need ways to encourage release site fidelity to mitigate suboptimal breeding, reduce mortality rates, and minimize human-wildlife conflicts. We studied initial movement ecology of elk (Cervus elaphus) fitted with GPS collars and re- introduced to the Missouri Ozarks in 2011 (n = 32), 2012 (n = 21), and 2013 (n = 31) for 6 mo post release. We assessed maximum displacement from the release site, range shifts, and range size across four sequential time frames (0–10 d, 11–31 d, 32–61 d, and 62–183 d). Compared to other elk restorations in eastern North America, site fidelity was high, with maximum distance from the release site 62–183 d post release ≤10 km for 94% of 2011 animals, 57% of 2012 animals, and 97% of 2013 animals. Elk range sizes were similar during the first 61 d post release but doubled in size 62–183 d post release to an average of 26.2 km2 (range: 4.0–218.8 km2). The average range overlap for individual elk in sequential time periods was between 23–26% across years, indicating elk used different areas over time. Release site had the greatest influence on initial movements; one site used in 2012 was associated with greater release site displacement and range sizes. Maternal cows also demonstrated higher site fidelity to the release site than nonmaternal cows. High site fidelity and small home ranges in elk recently restored to Missouri may be attributed to soft release, minimal human disturbance, quality habitat, and release groups of mature females.

Primate rehabilitation is challenging but has become crucial as many species are threatened with extinction. Vervet monkeys (Chlorocebus aethiops) are a widespread primate species in Africa. Despite the release of comparatively large numbers of rehabilitated monkeys, the success rate is poor, with low survival. This is partly due to choosing substandard release sites. Here we use an environmental envelope model that combines species-specific environmental and spatial data (including environmental conditions such as temperature and rainfall, access to permanent water, and proximity to anthropogenic influence) to predict the best areas for release of rehabilitated vervet monkeys in KwaZulu-Natal, South Africa. Approximately 80% of the land in KwaZulu-Natal qualifies as general habitat. However, only 6225 km2 (6.7%) is classed as habitat desirable for release, as human occupation and limited water access render other areas unsuitable. Unsurprisingly, ideal release land is limited and may prove difficult to access. However, there are accessible land areas that may be viable despite human impact. This uncertainty highlights the need for site visits early in the selection process. Our model provides easily read maps that rehabilitators can use to assist with this process and potentially optimize release site selection. This method could be easily adapted to other primate species.

Methyl salicylate (MeSA) is a commonly emitted herbivore-induced plant volatile (HIPV) known to attract insect predators in agricultural crops. However, thorough studies on whether MeSA can increase their ecological functioning or their attraction under field conditions are still lacking. Here, we conducted laboratory, greenhouse, and field studies to address the hypothesis that two agriculturally important predatory insects (the ladybeetle Hippodamia convergens Guerin-Meneville and the lacewing Chrysoperla rufilabris Burmeister) respond physiologically and behaviorally to MeSA, which may lead to increased predation and oviposition. In laboratory studies using electro-antennography, we found that male and female H. convergens and C. rufilabris antennae can detect MeSA; however, for both species, female antennae responded more strongly. In greenhouse studies using cages and wind tunnels, H. convergens females were attracted to, and arrested by, MeSA; this attraction increased egg predation. Attraction of C. rufilabris females to MeSA also increased oviposition. In field studies, mark-release-recapture experiments were performed to investigate H. convergens and C. rufilabris attraction to MeSA over various distances in cranberry fields. More H. convergens and C. rufilabris were caught on yellow sticky cards placed close (0–30 m) to the predator release site than at farther distances, regardless of whether the cards were baited with MeSA or not. In conclusion, H. convergens and C. rufilabris adults detected, and were attracted to, MeSA under laboratory and greenhouse conditions, resulting in higher predation and oviposition, but this attraction was not observed under field conditions. These results demonstrate that predator responses to HIPVs can be complex in real agricultural settings.

We assessed the suitability of targeted removal as a means for tuberculosis (TB) control on an intensely managed Eurasian wild boar (Sus scrofa) hunting estate. The 60 km large study area included one capture (treatment) site, one control site, and one release site. Each site was fenced. In the summers of 2012, 2013 and 2014, 929 wild boar were live-captured on the treatment site. All wild boar were micro-chipped and tested using an animal side lateral flow test immediately after capture in order to detect antibodies to the Mycobacterium tuberculosis complex (MTC). The wild boar were released according to their TB status: Seropositive individuals onto the release site (hunted after summer), and seronegative individuals back onto the treatment site. The annual summer seroprevalence of antibodies to the MTC declined significantly in live-captured wild boar piglets from the treatment site, from 44% in 2012 to 27% in 2013 (a reduction of 39%). However, no significant further reduction was recorded in 2014, during the third capture season. Fall-winter MTC infection prevalence was calculated on the basis of the culture results obtained for hunter-harvested wild boar. No significant changes between hunting seasons were recorded on either the treatment site or the control site, and prevalence trends over time were similar on both sites. The fall-winter MTC infection prevalence on the release site increased significantly from 40% in 2011–2012 to 64% in 2012–2013 and 2013–2014 (60% increase). Recaptures indicated a persistently high infection pressure. This experiment, the first attempt to control TB in wild boar through targeted removal, failed to reduce TB prevalence when compared to the control site. However, it generated valuable knowledge on infection pressure and on the consequences of translocating TB-infected wild boar., This is a contribution to Spanish Government MINECO Plan Nacional grant AGL2014-56305 and FEDER, to CDTI, and to the EU FP7 WIldTBvac#613779 grant. Azlan Che’Amat has a PhD grant from the Malaysian Government.

Dispersal from the release site and high mortality are two main factors that contribute to low retention of hard-released translocated wildlife. A soft-release translocation is a method that may increase the likelihood of translocation success because individuals are forced to acclimatize and become familiar to the new release site prior to the translocation. The objective of this study was to compare the movement patterns and retention rate of resident and translocated Egyptian tortoises that were translocated just prior to the start of the aestivation season and therefore were forced to aestivate at the release site (a forced in-activity soft-release). The retention rate of translocated tortoises, the proportion of tortoises that remained at the release site and alive by the end of the study, was 71% (5/7) compared to a retention rate of 100% for resident tortoises. There was no significant difference in the minimum convex polygon area, total distance moved, or the number of relocations during the activity season between resident and translocated tortoises. Our results suggest that a forced in-activity soft release consisting of translocating Egyptian tortoises just before the aestivation season may be effective in minimizing dispersal from the release site.

Background The discovery of CRISPR-based gene editing and its application to homing-based gene drive systems has been greeted with excitement, for its potential to control mosquito-borne diseases on a wide scale, and concern, for the invasiveness and potential irreversibility of a release. Gene drive systems that display threshold-dependent behavior could potentially be used during the trial phase of this technology, or when localized control is otherwise desired, as simple models predict them to spread into partially isolated populations in a confineable manner, and to be reversible through releases of wild-type organisms. Here, we model hypothetical releases of two recently engineered threshold-dependent gene drive systems—reciprocal chromosomal translocations and a form of toxin-antidote-based underdominance known as UDMEL—to explore their ability to be confined and remediated. Results We simulate releases of Aedes aegypti, the mosquito vector of dengue, Zika, and other arboviruses, in Yorkeys Knob, a suburb of Cairns, Australia, where previous biological control interventions have been undertaken on this species. We monitor spread to the neighboring suburb of Trinity Park to assess confinement. Results suggest that translocations could be introduced on a suburban scale, and remediated through releases of non-disease-transmitting male mosquitoes with release sizes on the scale of what has been previously implemented. UDMEL requires fewer releases to introduce, but more releases to remediate, including of females capable of disease transmission. Both systems are expected to be confineable to the release site; however, spillover of translocations into neighboring populations is less likely. Conclusions Our analysis supports the use of translocations as a threshold-dependent drive system capable of spreading disease-refractory genes into Ae. aegypti populations in a confineable and reversible manner. It also highlights increased release requirements when incorporating life history and population structure into models. As the technology nears implementation, further ecological work will be essential to enhance model predictions in preparation for field trials.

Large carnivores are frequently reintroduced into protected areas to compensate for anthropogenic-driven losses. The lack of post-release monitoring has impeded our knowledge on how these carnivores adapt to their new environment, which often results in uncertainty of whether or not reintroductions were successful. Between 2011 and 2012, six leopards (Panthera pardus) and three lions (Panthera leo) were reintroduced into Majete Wildlife Reserve, Malawi, and each animal was fitted with a GPS or VHF collar to monitor their post-release movements and behaviour. All individuals survived longer than two and a half years post-release and successful breeding events were recorded for all females, except one leopard. Released felids showed little initial exploratory behaviour, none homed to their capture location and all individuals displayed at least some degree of release site fidelity. Lions established permanent ranges between five and seven months after release, with a mean home range of 82.1km2 (95%, T-LoCoH). Three leopards established permanent ranges between four and eight months, with a mean home range of 181.6 km2 (95%; T-LoCoH). Two leopards did not establish fixed home ranges, but rather exhibited continuous shifts in range which were likely due to natural disruptive events such as season, prey availability and other competitors. Our findings suggest that reintroduced felids may take longer to establish permanent home ranges than previously thought, highlighting the importance of long-term post-release monitoring. Based on our study, reintroduction appears to be an effective and viable tool to restore large carnivores in protected areas in Malawi.

The movements of adult Atlantic salmon Salmo salar were determined as they migrated to spawning habitats in a large lacustrine catchment, Lough Neagh, in Northern Ireland. The minimum average ground speed of S. salar through the lake was 2·1 km day(-1) and the mean residence time was 11 days. Tagged S. salar tended to actively migrate through the lake which represented a transitory habitat for adult S. salar. Migration time from the release site, through the lake, to a spawning tributary decreased during the migratory period. During the 4 year study period between 20·5 and 41·6% of tagged S. salar which entered the lake each year, explored at least one other channel before ascending the final spawning tributary. Exploratory behaviour was more likely in S. salar which spawned in the tributaries furthest from the sea. Exploratory behaviour was also more likely to occur during periods of reduced discharge in the natal stream. The fishery management implications of complex pre-spawning behaviour in a mixed stock lacustrine system, are discussed.

There is growing concern about mitigation-driven translocations that move animals from anthropogenic threats at donor sites because of their failure rate and lack of application of scientific principles and best practice. We reviewed all known lizard translocations in New Zealand between 1988 and 2013 and identified 85 translocations of 30 lizard taxa to 46 release sites. Most translocations (62%) were motivated by conservation goals for the species or the release site, and one-third were mitigation-driven translocations, typically motivated by habitat loss due to development. Mitigation-driven translocations began in 2003, and since that time have equalled the number of conservation-motivated translocations. Conservation-motivated translocations usually released lizards on islands without mammalian predators, whereas mitigation-driven translocations usually relocated lizards to mainland sites with introduced predators. Long-term monitoring has been sparse and often rudimentary. Eight lizard trans...

The home range and characteristics of Cottus koreanus were investigated using passive integrated transponder (PIT) telemetry in the Gulji Stream, Korea, where the target species was artificially translocated. After release, tagged individuals moved up to 78 m away from the release site in search of proper habitats. The average distance moved until settlement was 17.1 m. The observed home range of settled individuals had longitudinal sections of 9.9 ± 3.6 m and surface areas of 7.2 ± 2.7 m2. This is comparable to congeneric species that inhabit similar ecological habitats. Once individuals had settled, they rarely moved from that site except during the spring season. The typical microhabitat characteristics of the sites where the released individuals settled are: water depth of 5–10 cm, water velocity of 0.1–0.3 m s−1, and the size of boulders and cobbles of 10–20 cm in diameter. This study of translocated C. koreanus individuals provides detailed information about habitats that can be used for eff...

The abundance and distribution of salmon lice Lepeophtheirus salmons originating from fish farms in a northern Norwegian fjord during the summer of 2010 was investigated by means of a numerical model, underpinned by field observations. In order to evaluate the robust- ness of the simulated distribution of the lice, we re-ran the simulation several times, changing the vertical responses of the lice to environmental cues such as light and turbulence, in addition to altering their vertical swimming velocity. The model was able to realistically reproduce the observed currents and stratification in the region. The simulated distribution of lice was not sensi- tive to different implementations of surface light nor to the light sensitivity level of the lice. How- ever, the vertical swimming velocity and a mixing parameter influenced both their vertical distri- bution and horizontal dispersion. The aggregation of lice along land was influenced by their response to turbulent water. The simulated infectious stages of the lice were transported on aver- age 20 to 45 km from their release site. The simulated concentrations of infectious lice varied in synchronisation with lice infestations observed on wild fish in the area. Less than 1% of the simu- lated lice reached a farm site. The ratio between internal and external exposure ranged from 7 to 57%. Farms in the north of the fjord system were more exposed to lice released in the south than vice versa.

Smolt-to-adult survival (SAS) and straying of subyearling fall Chinook Salmon Oncorhynchus tshawytscha that were acclimated in waters of their release site before river release was compared with those of fish that were transported to the river and released directly into the river. Results showed that there were no differences in average SAS, which was 0.08% for both acclimated and direct-release groups, or straying, which averaged 33.8% and 35.3% for direct and acclimated release groups, respectively. We conclude that an acclimation period may not improve these metrics in subyearling-released salmon.Received June 19, 2015; accepted October 31, 2015

Abstract ContextTranslocation is a widely used non-lethal tool to mitigate human–wildlife conflicts, particularly for carnivores. Multiple intrinsic and extrinsic factors may influence translocation success, yet the influence of release-site landscape context on the success of translocations of wildlife involved in nuisance behaviour is poorly understood. Moreover, few studies of translocated wildlife involved in nuisance behaviour have provided estimates of translocation success under different scenarios. AimsWe evaluated the role of intrinsic (age, sex) and extrinsic (translocation distance, landscape composition) features on translocation success of American black bears (Ursus americanus) involved in nuisance behaviour and provide spatially explicit predictions of success under different scenarios. MethodsWe analysed data from 1462 translocations of 1293 bears in Wisconsin, USA, from 1979 to 2016 and evaluated two measures of translocation success: repeated nuisance behaviour and probability of returning to a previous capture location. Key resultsTranslocation distances ranged from 2 to 235km (mean=57km). Repeated nuisance behaviour was recorded following 13.2% of translocation events (192 of 1457) and was not significantly affected by translocation distance. Bears repeated nuisance behaviour and were recaptured at their previous captures site (i.e. returned) after 64% of translocation events (114 of 178). Return probability decreased with an increasing translocation distance, and yearling bears were less likely to return than were adults. The proportions of agriculture and forest within 75km and 100km respectively, of the release site had positive and negative effects on return probability. ConclusionsMangers can use bear characteristics and landscape context to improve translocation success. For example, achieving a 10% predicted probability of return would require translocation distances of 49–60km for yearlings in low-agriculture and high-forest landscapes. In contrast, estimated return probability for adults was ≥38% across all translocation distances (0–124km) and almost all landscape contexts. ImplicationsOur results emphasise the importance of considering the effects of landscape conditions for developing spatially explicit guidelines for maximising translocation success.

Sterile insect technique (SIT) is a promising, environmentally friendly alternative to the use of pesticides for insect pest control. However, implementing SIT with Aedes aegypti (Linnaeus) mosquitoes presents unique challenges. For example, during transport from the rearing facility to the release site and during the actual release in the field, damage to male mosquitoes should be minimized to preserve their reproductive competitiveness. The short flight range of male Ae. aegypti requires elaborate release strategies such as release via Unmanned Aircraft Systems, more commonly referred to as drones. Two key parameters during transport and release are storage temperature and compaction rate. We performed a set of laboratory experiments to identify the optimal temperatures and compaction rates for storage and transport of male Ae. aegypti. We then conducted shipping experiments to test our laboratory-derived results in a ‘real-life’ setting. The laboratory results indicate that male Ae. aegypti can survive at a broad range of storage temperatures ranging from 7 to 28°C, but storage time should not exceed 24 h. Male survival was high at all compaction rates we tested with a low at 40 males/cm3. Interestingly, results from our ‘real-life’ shipping experiment showed that high compaction rates were beneficial to survival. This study advances key understudied aspects of the practicalities of moving lab-reared insects into the field and lies the foundation for further studies on the effect of transport conditions on male reproductive fitness.

Re-introduction programme has been adopted in solving the conflict issues related with the Malayan sun bears in Peninsular Malaysia. Two rehabilitated sun bears (#1533 and #1532) were collared and released in Tembat Forest Reserve, Hulu Terengganu to study the home-range and activity pattern. Tracking of sun bear in wild have be conducted manually by using telemetry devices namely radio frequency systems and GPS-UHF download system. A total of 912 locations were recorded. The home range size (indicate by the size of convex polygon) of bear #1533 is larger than bear #1532, with value of 95% minimum convex polygon was 130 km2 compared to its counterpart was 33.28 km2. Bears moved to forest (primary and secondary) and oil palm area. Bear #1533 and #1532 were more active in daytime (diurnal) especially from sunrise to midday. Activity pattern of both rehabilitated bears suggested influence by their daily activity in captivity. This study has proposed two guidelines in re-introduction, 1) minimum distance between release site and possible conflict area is 10–13 km and 2) release during the bear’s active time.Re-introduction programme has been adopted in solving the conflict issues related with the Malayan sun bears in Peninsular Malaysia. Two rehabilitated sun bears (#1533 and #1532) were collared and released in Tembat Forest Reserve, Hulu Terengganu to study the home-range and activity pattern. Tracking of sun bear in wild have be conducted manually by using telemetry devices namely radio frequency systems and GPS-UHF download system. A total of 912 locations were recorded. The home range size (indicate by the size of convex polygon) of bear #1533 is larger than bear #1532, with value of 95% minimum convex polygon was 130 km2 compared to its counterpart was 33.28 km2. Bears moved to forest (primary and secondary) and oil palm area. Bear #1533 and #1532 were more active in daytime (diurnal) especially from sunrise to midday. Activity pattern of both rehabilitated bears suggested influence by their daily activity in captivity. This study has proposed two guidelines in re-introduction, 1) minimum distance betw...

According to the olfactory navigation hypothesis, birds are able to exploit the spatial distribution of environmental odourants to determine the direction of displacement and navigate from non-familiar locations. The so-called "olfactory activation hypothesis" challenged the specific role of olfactory cues in navigation by suggesting that olfactory stimuli only activate a navigational system that is based on non-olfactory cues, predicting that even artificial odourants alone are sufficient to allow unimpaired navigation. In this experiment, we compared tracks of experimental birds exposed to different olfactory stimuli before being made anosmic at the release site prior to release. One group of pigeons was exposed to purified air enriched with artificial odourants, while a second group was exposed to environmental air. The birds stimulated with artificial nonsense odourants displayed several behavioural differences from both untreated controls and anosmic pigeons exposed to environmental air prior to release: nonsense odourants birds were unable to determine the home direction, they mostly flew within a space outside the homeward oriented quadrant, and they flew shorter distances on the day of release. Our data failed to support a mere activational role of olfactory stimuli in navigation, and are consistent with the olfactory navigation hypothesis. published

Homing tracks of two groups of pigeons, Columba livia f. domestica, were analyzed in view of difference between individual birds and correlations between characteristic variables, looking at the initial phase while the pigeons were still at the release site, and the homing phase separately. Individual birds differed significantly in their flying speed during the initial phase, and one pigeon tended to stay longer at the release site than the others. There were no significant differences in steadiness and efficiency, indicating that all pigeons homed equally well. Differences in correlation dimension, a variable reflecting the complexity of the navigational process, reflect differences in the use of navigational information, with one bird apparently using less complex information than others. The flying speed during the initial phase was positively correlated with the flying speed during the homing phase. During the homing phase, the steadiness of flight and the efficiency of homing were closely correlated, and both tended to be positively correlated with the correlation dimension, suggesting that birds that use more complex navigational information home more efficiently.

Reintroductions are used to re-establish populations of species within their indigenous range, but their outcomes are variable. A key decision when developing a reintroduction strategy is whether to include a temporary period of confinement prior to release. Pre-release confinement is primarily used for the purpose of quarantine or as a delayed-release tactic to influence the performance or behaviour of founders post-release. A common difference between these approaches is that quarantine tends to be conducted in ex situ captivity, whereas delayed releases tend to involve in situ confinement at the release site. Although these practices are commonly viewed independently, it may be possible for a single confinement period to be used for both purposes. We tested whether temporarily holding wild eastern bettongs Bettongia gaimardi in ex situ captivity for 95–345 days prior to release (delayed release) influenced their body mass, pouch occupancy or survival during the first 1.5 years post-release, compared to founders released without confinement (immediate release). Our results suggest that exposing founders to captivity did not alter their body mass or performance post-release, despite being heavier and having fewer pouch young when released. We conclude that, for this species, ex situ captivity does not represent a tactical opportunity to improve post-release performance but can be used for quarantine without affecting the probability of establishment.

In this study, behaviour and survival following catch-and-release (C&R) angling was investigated in wild Atlantic salmon Salmo salar (n = 75) angled on sport fishing gear in the River Otra in southern Norway at water temperatures of 16.3-21.1 °C. Salmo salar were tagged externally with radio transmitters and immediately released back into the river to simulate a realistic C&R situation. The majority of S. salar (91%) survived C&R. Most S. salar that were present in the River Otra during the spawning period 3-4 months later were located at known spawning grounds. Downstream movements (median furthest position: 0.5 km, range: 0.1-11.0 km) during the first 4 days after release were recorded for 72% of S. salar, presumably stress-induced fallback associated with C&R. Individuals that fell back spent a median of 15 days before commencing their first upstream movement after release, and 34 days before they returned to or were located above their release site. Mortality appeared to be somewhat elevated at the higher end of the temperature range (14% at 18-21 °C), although sample sizes were low. In conclusion, C&R at water temperatures up to 18 °C had small behavioural consequences and was associated with low mortality (7%). Nevertheless, low levels of mortality occur due to C&R angling and these losses should be accounted for by management authorities in rivers where C&R is practised. Refinement of best practices for C&R may help to reduce mortality, particularly at warmer temperatures.

Initial orientation of crested newts Triturus cristatus and smooth newts Lissotriton vulgaris was measured following passive displacement to arenas placed at 12 test sites 0.213–24.2 km distant from the breeding pond. Newts were transported by car without visual and olfactory outward journey information, but had full access to local orientation clues at the release site during the night and early morning before testing. Within the area of previous migratory experience, the initial directional choice of both species was significantly directed to home. Outside the area of familiarity, the initial orientation was indistinguishable from random in all but one site each at 3 and 20 km distance, respectively. We suggest that short-distance orientation was probably based on olfactory beaconing and on a learned spatial map integrating visual and olfactory information. The failure of homeward orientation following long-distance displacement indicates the absence of a spatial map which allows for extrapolation into ...

Translocations are increasingly used in species conservation, but success rates can be low. Experimental approaches are needed to compare the outcomes of translocation strategies, including those involving head-starting (the rearing of juveniles in captivity before release). Here, we studied the reintroduction of head-started and wild-caught juveniles of a distinctive reptile, the tuatara Sphenodon punctatus, on the South Island of New Zealand. We compared morphometric, ecophysiological, behavioural and spatial aspects for juveniles from three groups (wild-caught from a warmer climate, head-started from a warmer climate and head-started from the local climate), focusing on the first 5 months of summer following release. Group did not affect body condition at recapture, but wild-caught juveniles, despite being the only animals with ticks at release, grew faster and had higher inferred body temperatures than individuals head-started in a warmer climate. Wild-caught juveniles were less frequently seen emerged than juveniles head-started at the release site, and no animals had ticks at the summer's end. Mean dispersal distance and home-range size did not differ significantly between groups, and all groups had high survival (96.4–100% over first summer; at least 66.7–73.3% after the first winter following release). We conclude that, for most metrics, post-release performance of head-started and wild-caught juvenile tuatara was similar, and that head-started groups can differ between each other as much as between captive and wild. Our results emphasize the species-specific nature of translocation outcomes.

Dispersal away from the release site is among the main obstacles that reduce translocation success. Scientists should therefore test a variety of translocation methods to reduce dispersal when moving wildlife between sites. The objective of this research was to examine how translocation method (hard- vs. soft-release) and habitat structure (continuous vs. patchy) affect movement of translocated turtles. A hard-release consists of releasing individuals to their new environment without any prior acclimation, whereas a soft-release forces animals to spend time at the release site prior to release. Our results suggest that the most effective translocation technique depends upon habitat structure. A soft-release was effective in minimizing post-release dispersal of translocated turtles in a continuous lotic habitat as there was no difference in the movement of soft-released and resident turtles. However, hard-released turtles undergo extensive movement when translocated to a continuous lotic habitat as hard-released turtles had greater movement than resident turtles. When the release site consists of a patchy wetland complex, a hard-release translocation may be effective as there was no difference in the movement between resident and hard-released turtles. Our study suggests that both the habitat structure of the release site and translocation method play a role in the movement patterns of translocated wildlife. Semi-aquatic turtles or species with poor vagility may make better candidates for hard-release translocations in patchy habitats because these species may be less likely or unable to disperse long distances as result of their behavior, physiology, or the structure of the release site.