Critical Life Stages Research Articles

Palliative care: Benefits when included early to treat cancer

This paper aims to understand palliative care (PC) when included as part of the treatment for patients with cancer and when there is no need to wait for the person to be in an advanced or terminal stage of the disease. Palliative care is considered as the care required by patients living critical stages of life. Therefore, palliative care should be included from the diagnosis phase of the disease in order to go hand in hand with treatment. This situation is of great importance, because as we are human beings, we have emotional, social, and spiritual needs so that we perceive ourselves in a wholesome way.

Using the VEMCO Positioning System (VPS) to explore fine-scale movements of aquatic species: applications, analytical approaches and future directions

Recent advancements in telemetry have redefined our ability to quantify the fine-scale movements of aquatic animals and derive a mechanistic understanding of movement behaviours. The VEMCO Positioning System (VPS) is a fine-scale commercial positioning system used to generate highly accurate semi-continuous animal tracks. To date, VPS has been used to study 86 species, spanning 25 taxonomic orders. It has provided fine-scale movement data for critical life stages, from tracking day-old turtle hatchlings on their first foray into the sea to adult fish returning to natal rivers to spawn. These high-resolution tracking data have improved our understanding of the movements of species across environmental gradients within rivers, estuaries and oceans, including species of conservation concern and commercial value. Existing VPS applications range from quantifying spatio-temporal aspects of animal space use and key aspects of ecology, such as rate of movement and resource use, to higher-order processes such as interactions among individuals and species. Analytical approaches have seen a move towards techniques that incorporate error frameworks such as autocorrelated kernel density estimators for home range calculations. VPS technology has the potential to bridge gaps in our fundamental understanding of fine-scale ecological and physiological processes for single and multi-species studies under natural conditions. Through a systematic review of the VPS literature, we focus on 4 principle topics: the diversity of species studied, current ecological and ecophysiological applications and data analysis techniques, and we highlight future frontiers of exploration.

Is there a critical life stage to promote physical activity for preserving cognitive function? Results from a population‐based birth cohort

AbstractBackgroundPhysical activity improves cognitive function across the life course, reducing the risk of all‐cause dementia in older ages. We aimed to identify the life course model that best describes the association between physical activity throughout life and cognitive performance at age 50.MethodAdults aged 50 participants of the National Child Development Survey (NCDS) were followed from birth (1958) to 2013. Physical activity was accessed using a self‐reported questionnaire in each wave. Participants were classified as physically active or inactive. Short‐term memory was assessed by word recall test while the executive function was assessed by letter cancelation and animal naming tests. Scores from both cognitive domains were reported as standard deviation (SD). The most appropriate life course model (critical, sensitive, or accumulation) to explain cognitive performance at age 50 was identified by partial F‐tests.ResultData from 4,103 adults were analyzed (53.8% women). At age 50, most participants were employees (74.3%), non‐smokers (80.3%), and overweight or obese (64.7%). Whilst 175 (4.0%) of participants were physically inactive at age 7, 44.9% practiced physical activity once a week or less at age 50. Physical activity at age 42 was defined as a critical period for better memory and executive function at age 50 in men. Among women, physical activity at age 23 was identified as a critical period for executive function while the sensitive model best explained the association between physical activity through the life course and memory at age 50. Women who were physically active at age 23 had a better executive function (1.13 [95%CI 1.06, 1.20] SD) than inactive counterparts. Better performance on memory test was observed in women physically active at age 7 (0.18 [95%CI: 0.02, 0.34] SD), 23 (0.11 [95%CI: 0.03, 0.18] SD) and 50 (0.08 [95%CI: 0.01, 0.15] SD). Physically active men at age 42 showed better performance in memory test (0.12 [95%CI: 0.03, 0.21] SD) and executive function (0.11 [95%CI: 0.04, 0.18] SD) than inactive respondents.ConclusionEarly childhood and adulthood for women and late‐adulthood for men were identified as important life stages to promote physical activity for preserving cognitive function at age 50.

Using metabolomic profiling to inform use of surrogate species in ecological risk assessment practices

The U.S. EPA frequently uses avian or fish toxicity data to set protective standards for amphibians in ecological risk assessments. However, this approach does not always adequately represent aquatic-dwelling and terrestrial-phase amphibian exposure data. For instance, it is accepted that early life stage tests for fish are typically sensitive enough to protect larval amphibians, however, metamorphosis from tadpole to a terrestrial-phase adult relies on endocrine cues that are less prevalent in fish but essential for amphibian life stage transitions. These differences suggest that more robust approaches are needed to adequately elucidate the impacts of pesticide exposure in amphibians across critical life stages. Therefore, in the current study, methodology is presented that can be applied to link the perturbations in the metabolomic response of larval zebrafish (Danio rerio), a surrogate species frequently used in ecotoxicological studies, to those of African clawed frog (Xenopus laevis) tadpoles following exposure to three high-use pesticides, bifenthrin, chlorothalonil, or trifluralin. Generally, D. rerio exhibited greater metabolic perturbations in both number and magnitude across the pesticide exposures as opposed to X. laevis. This suggests that screening ecological risk assessment surrogate toxicity data would sufficiently protect amphibians at the single life stage studied but care needs to be taken to understand the suite of metabolic requirements of each developing species. Ultimately, methodology presented, and data gathered herein will help inform the applicability of metabolomic profiling in establishing the risk pesticide exposure poses to amphibians and potentially other non-target species.

Can Weight Watchers (WW) Help Address Maternal Obesity? An Audit of Weight Change in Women of Childbearing Age and Mothers-To-Be, Referred into a Commercial Slimming Programme

ObjectivesThe scale of overweight and obesity amongst women of childbearing age or mothers to be, living in Wales, places a considerable burden on the NHS and public health. High BMI (over 30) during pregnancy increases the health risks for mother and baby. Policy advice recommends weight management services are available to help women lose weight before and whilst planning pregnancy. In parts of Wales, NHS partnerships with commercial companies provide weight management services for women considering or planning pregnancy. This study evaluates whether an established referral Weight Watchers (WW) programme, known to be effective in adults in England, can help mothers-to-be living in North Wales lose weight.MethodsAnalysis used routine data from 82 referrals to WW between June 2013 and January 2015. Participants received a referral letter inviting them to attend face-to-face group workshops combined with a digital experience. The programme encompassed healthy eating, physical activity and positive mind-set. Trained WW staff measured bodyweight before, during and at 12 weeks. On entry to the course, participants had a median age of 31.4 years (interquartile range (IQR) 28–34) with a median BMI of 36.8 kg/m2 (IQR 33.3–43.7).ResultsWomen completing the course (n = 34) had a median weight loss of 5.65 kg (IQR 0.45–10.85), equating to 5.7% (SD 3.46) of initial body weight. Intention-to-treat analysis (last observation carried forward), which included lapsed courses n = 66, showed a median weight loss of 3.6 kg (IQR − 2.53 to 9.73), equating to 3.7% (SD 3.62) of initial body weight. Overall, there was significant weight loss during the WW programme (Wilcoxon signed rank test Z = − 6.16; p < 0.001). Weight loss was significantly correlated with the number of workshops attended (Spearman correlation coefficient 0.61 p < 0.001). The proportion of all 82 participants (intention to treat, baseline observation carried forward) that achieved a weight loss of ≥ 5% initial weight was 30.5%.Conclusions for PracticeReferral of obese mothers-to-be into WW can successfully achieve short-term weight loss, at or above 5%, in approximately one third of participants. The dose–response effect supports a causal inference. Successful weight loss at this critical life stage may provide women with the necessary motivation to initiate weight loss for healthy pregnancy, however further research is required.

Boat noise impacts early life stages in the Lusitanian toadfish: A field experiment

Marine traffic is the most common and chronic source of ocean noise pollution. Despite the evidence of detrimental effects of noise exposure on fish, knowledge about the effects on the critical early life stages - embryos and larvae - is still scarce. Here, we take a natural habitat-based approach to examine potential impacts of boat noise exposure in early life stages in a wild fish population of the Lusitanian toadfish (Halobatrachus didactylus). In-situ experiments were carried out in the Tagus estuary, an estuary with significant commercial and recreational boat traffic. Nests with eggs were exposed to either ambient (control) or boat noise (treatment), for 1 fortnight. Eggs were photographed before being assigned to each treatment, and after exposure, to count number of eggs and/or larvae to assess survival, and sampled to study development and oxidative stress and energy metabolism-related biomarkers. Data concerns 4 sampling periods (fortnights) from 2 years. Results indicate that offspring survival did not differ between treatments, but boat noise induced a detrimental effect on embryos and larvae stress response, and on larvae development. Embryos showed reduced levels of electron transport system (ETS), an energy metabolism-related biomarker, while larvae showed higher overall stress responses, with increased levels of superoxide dismutase (SOD) and DNA damage (oxidative stress related responses), ETS, and reduced growth. With this study, we provided the first evidence of detrimental effects of boat noise exposure on fish development in the field and on stress biomarker responses. If these critical early stages are not able to compensate and/or acclimate to the noise stress later in the ontogeny, then anthropogenic noise has the potential to severely affect this and likely other marine fishes, with further consequences for populations resilience and dynamics.

Associations of Diet Quality with Midlife Brain Volume: Findings from the UK Biobank Cohort Study.

Higher quality diets may be related to lower dementia rates. Midlife is emerging as a critical life stage for a number of dementia risk factors. This study examines whether diet quality is related to brain structure during midlife, and if this differs by sex. This study used data from 19184 UK Biobank participants aged 40-65 years. Diet quality was assessed using three dietary indices including the Mediterranean Diet Score (MDS), Healthy Diet Score (HDS), and Recommended Food Score (RFS). MRI brain measures included total, grey, white and hippocampal volume. Linear regression examined associations between diet quality and brain volume, controlling for potential confounders. Better quality diet across all indices was significantly related to larger grey matter volume: MDS β= 429.7 (95%CI: 65.2, 794.2); HDS β= 700.1 (348.0, 1052.1); and RFS β= 317.1 (106.8, 527.3). Higher diet scores were associated with greater total volume: HDS β= 879.32 (286.13, 1472.50); RFS β= 563.37 (209.10, 917.65); and white matter volume: RFS β= 246.31 (20.56, 472.05), with the exception of Mediterranean diet adherence. Healthy eating guidelines and dietary variety associations with total and grey matter volume were more prominent in men. Findings suggest that diet quality is associated with brain structure during midlife, potentially decades prior to the onset of dementia.

Abortion: Life-Course Stages and Disruptive Life Events

AbstractPregnancy termination and its interplay with critical life stages and events has rarely been subjected to careful scrutiny in the social sciences, mainly due to a lack of high-quality survey data. Using the first eleven waves (2008–2018) of the German Family Panel Study (pairfam) and employing linear probability models, we examine women and also men with partners who either had induced abortion (N=260 women; N=170 men) or became parents (N=1478 women; N=1220 men). We frame abortion as a social process in which life circumstances and disruptive life events fundamentally shape the decision to carry a pregnancy to term or to discontinue it. We find that teenage or late pregnancy, educational enrollment, previous children, partnership dissolution, and economic uncertainty are associated with induced abortion. Our evidence suggests that abortion decisions are powerfully shaped by life-course contingencies and their complex intertwining.

Do correctional facilities correct our youth?: Effects of incarceration and court-ordered community service on personality development.

Millions of individuals are currently incarcerated in the United States. However, little is known about the effects of incarceration on personality development, particularly during the critical life stage of adolescence. In a large longitudinal sample, adolescents and young adults (N = 7,736) regularly completed personality measures and assessments of court-ordered punishments over more than 10 years. Using propensity score weighting and multilevel growth curve modeling, we found that personality prospectively predicted the likelihood of incarceration and court-ordered community service. Specifically, individuals who were higher in sensation seeking, impulsivity, and depressive symptoms were more likely to be incarcerated-results for community service youth mostly mirrored these findings. Mixed evidence was found for patterns of trait change. Incarcerated, community service, and nonoffending youth were similar in several ways-all increased on sensation seeking and self-esteem and decreased on impulsivity over the 10-year period. However, between-person models found that incarcerated youth evidenced a greater decrease in depressive symptoms and a slower decrease in impulsivity, and youth assigned community service increased more quickly on sensation seeking than their nonoffending peers. Within-person analyses also suggested personality differences; for example, sensation seeking was lower after incarceration while impulsivity was higher compared with before. Overall, this work highlights that personality predicts incarceration and court-ordered community service in youth and that personality changes linked with these experiences do not have a uniformly "corrective" pattern of change, with few effects observed overall and some in seemingly unfavorable directions. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Exposure of Helicoverpa punctigera pupae to extreme temperatures for extended periods negatively impacts on adult population dynamics and reproductive output.

Understanding the impact that heat stress has on critical life stages of an organism is essential when assessing population responses to extreme events. Heat stress may occur as repeated small-scale events or as a single prolonged event, which may cause different outcomes to the organism. Here, we subjected Helicoverpa punctigera (Wallengren) pupae to two temperatures (44.2°C and 43°C) and two exposure treatments - a single 3-h prolonged exposure prolonged and three repeated 1-h exposure period with 24h recovery time between bouts - to assess the biological traits of individuals. The maximum temperatures were used as they were just below the critical thermal maximum (CTmax) 47.3°C±0.3°C of pupae for which they could survive exposure. Adults in the prolonged and repeated heat-stressed treatments had 1.70 and 3.34 more days to emergence and 1.57 and 3.30 days extended life span compared to those kept under a constant 25°C temperature (control treatment). Both pre-oviposition and oviposition periods were extended in the heat-stressed groups. Fecundity in the prolonged and repeated heat-stressed females was reduced by 34.7% and 65.5% eggs in the 43°C treatment group and by 94.3% and 93.6% eggs in the 44.2°C treatment group compared to the control group. No eggs from females in either the prolonged and repeated heat-stress groups hatched. We establish that heat stress on pupae can influence the population dynamics of H. punctigera by reducing fecundity as well as extending the pre oviposition period, and affecting adult development. Also, as heat exposure on the parent generation resulted in no offspring production, it is critical to assess cross-generational responses to extreme heat stress.

Absence of Fathers in Childrens' Lives of Divorced Parents: Impact and Implication

The purpose of this study is to determine through scientific methods to what extent children experience parental divorce and the lack of fathers in families. This paper focuses on measuring the impact it has on adolescent children, between 13-18 years, in Tirana, Albania. Adolescence is one of the most critical stages of life and is very decisive for the future of children. This goal is enabled through the achievement of the following objectives such as: How and to what extent divorce and the lack of father affect the psychoemotional development and perception of children with divorced parents (ChDP) about their future and love relationships; to what extent does the lack of father affect this segment of children, and the identification of consequences to these children. Methodology: This involves a primary survey with the help of a structured questionnaire among children from the age group of 13-18 years in Tirana. The consequences of divorce are theoretically explained and give the opportunity to raise research questions in recent years. Questionnaire is the research instrument which includes questions about the relationship of children with their non-custodial parent, the impact of missing obligations, and the possible consequences for this segment of children. The data are compared with children of the same age, but from intact families, and have led to conclusions and recommendations on social policies to be followed towards this segment in the future.

100 years of insulin-enormous gratitude for my extra 65 years!

My name is Peter Davies, and with this year being the one hundredth anniversary of insulin, it is a tremendous honour to be invited to write this account of my life with Diabetes.

Environmental threats and conservation implications for Atlantic salmon and brown trout during their critical freshwater phases of spawning, egg development and juvenile emergence

AbstractAtlantic salmonSalmo salarL. and brown troutSalmo trutta farioL. are species of high socio‐economic and ecological value. Declining populations make them target species of fisheries management. This paper reviews the direct effects of deficient longitudinal connectivity, changes in discharge, high water temperatures, oxygen depletion, changes in water chemistry and increasing loads of fine sediment on the critical life stages of spawning, egg incubation and emergence. It further provides an overview about the basic autecological requirements of Atlantic salmon and brown trout and summarises important thresholds of physico‐chemical tolerances. This collection of information provides important baselines for assessing historical, ongoing and new threats relevant for the management of both species in fresh waters. Critical early‐life stages of both species are almost identical, creating synergies in conservation and restoration. Seaward‐migrating forms are exposed to further stressors, but improving starting conditions can also greatly improve their resilience.

Water level induced changes of habitat quality determine fish community composition in restored and modified riverbanks of a large alpine river

AbstractBank habitats provide important functions for riverine fish. Yet, they have been heavily modified by land use, technical flood protection measures, and hydropower installations. Fish species requiring specific habitats to complete their life cycle have strongly declined and therefore become target species of river restoration measures. This study compared abiotic conditions and fish community composition of three bank habitat types in a large alpine river, comprising different degrees of alteration compared to the natural state (concrete profile, bank riprap, and naturally restored riverbank). Significant differences in abiotic habitat characteristics such as bed material, water depth, turbidity, submerged vegetation, and temperature were detected between the three bank habitat types and sampling seasons. These water level‐dependent structural changes had the strongest effect on fish community composition as detected by distance‐based linear modeling. Small specimens between 3 and 13 cm TL and juveniles were most abundant in the restored areas, except for Lota lota, which was most abundant in the man‐made bank riprap. Target species of conservation were mostly detected in restored areas, particularly the critical young life stages of Chondrostoma nasus, Barbus barbus, and Thymallus thymallus. Water level strongly determined accessibility and suitability of bank habitats, with shallow, gravel‐dominated habitats comprising flat bank angles being most beneficial for these species. The findings of this study provide evidence for the success of bank habitat restoration in structurally impacted alpine rivers on target species of conservation. Fluctuating water levels and discharges typical for alpine rivers should be better considered in restoration planning, particularly in light of climate change, affecting the timing and amplitude of discharge in these systems.

Subchronic impacts of 2,4-D herbicide Weedestroy®AM40 on associative learning in juvenile yellow perch (Perca flavescens).

Aquatic herbicides are commonly used to control a wide variety of invasive and nuisance plants. One common active ingredient used in commercial herbicide formulations in Midwestern states is 2,4-dichlorophenoxyacetic acid (2,4-D). Due to the stability of 2,4-D in aquatic environments, many non-target aquatic species experience prolonged exposure throughout critical developmental life stages that can affect essential behaviors. However, the impacts of 2,4-D exposure on learning behaviors in juvenile fish are poorly understood. Therefore, we conducted a series of experiments using a maze environment to determine the effects of a commercial 2,4-D amine salt herbicide formulation (Weedestroy®AM40; WAM40; at 0.00, 0.50, 2.00, and 50.00 mg/L 2,4-D acid equivalent (a.e.)) exposure on juvenile yellow perch's ability to perform a feed associated learning behavior. We observed a significant decrease in the ability of yellow perch to correctly complete the feed associated learning behavior within 200 s when exposed to WAM40 at 2.00 and 50.00 mg/L 2,4-D as compared to controls (p=0.0002; p < 0.0001, respectively) and within 600 s when exposed to WAM40 at 2.00 and 50.0 mg/L 2,4-D as compared to the controls (p=0.0107 and p < 0.0001). These data suggest that exposure to 2,4-D in WAM40 can both increase the amount of time it takes for yellow perch to complete a feed associated learning behavior and/or obstruct the behavior altogether. Further experiments showed no significant decreases in locomotion (p > 0.05), hunger motivation (p > 0.05), and a visually guided startle response (p > 0.05), in all treatment groups tested as compared to controls. This suggests that 2,4-D in WAM40 does not inhibit feed associated learning behaviors via interaction with these mechanisms. Altogether, the results indicate that the use of 2,4-D herbicides for weed control in aquatic ecosystems could present risks to cognitive functions that control essential behaviors of yellow perch.

Habitat Preferences of Italian Freshwater Fish: A Systematic Review of Data Availability for Applications of the MesoHABSIM Model

The MesoHABitat SImulation Model (MesoHABSIM) is the preferred method to calculate spatio-temporal variation in the fish habitat availability in Italian rivers. With the aim of improving the applicability of the MesoHABSIM approach in the Italian territory, we carried out a systematic review of physical habitat preferences for 31 freshwater fish species and three freshwater lampreys, representing 75% of the total indigenous freshwater fish community of Italy. Information related to suitable ranges of depth, flow velocity, biotic/abiotic substrates, covers/shelters was collected and summarized for two critical life stages (adult and juvenile) and two bioperiods (rearing/growth and spawning). Overall, 250 publications were reviewed, classified as 206 peer-reviewed papers, 20 books, 7 PhD thesis, and 17 grey literature sources. Our analysis revealed substantial deficits of information about habitat requirements for more than 30% of Italian freshwater fish species. This information is particularly scarce for the most threatened endemic species, especially for their most critical bioperiod (i.e., spawning). With the aim of preserving freshwater fish biodiversity as required in the EU Biodiversity Strategy for 2030 (European Commission, 2020), accurate information on physical habitat requirements for spawning is crucial. As an example application of MesoHABSIM, the collected habitat preference information was used to define and apply mesohabitat suitability criteria for one fish species (Telestes muticellus) in a regulated river reach of Argentina Creek (Province of Imperia, Italy). This analysis demonstrates the potential for applying information from the current review to other fish species.

Sex Steroids and the Shaping of the Peripubertal Brain: The Sexual-Dimorphic Set-Up of Adult Neurogenesis.

Steroid hormones represent an amazing class of molecules that play pleiotropic roles in vertebrates. In mammals, during postnatal development, sex steroids significantly influence the organization of sexually dimorphic neural circuits underlying behaviors critical for survival, such as the reproductive one. During the last decades, multiple studies have shown that many cortical and subcortical brain regions undergo sex steroid-dependent structural organization around puberty, a critical stage of life characterized by high sensitivity to external stimuli and a profound structural and functional remodeling of the organism. Here, we first give an overview of current data on how sex steroids shape the peripubertal brain by regulating neuroplasticity mechanisms. Then, we focus on adult neurogenesis, a striking form of persistent structural plasticity involved in the control of social behaviors and regulated by a fine-tuned integration of external and internal cues. We discuss recent data supporting that the sex steroid-dependent peripubertal organization of neural circuits involves a sexually dimorphic set-up of adult neurogenesis that in turn could be relevant for sex-specific reproductive behaviors.

A role for metabolism in determining neonatal immune function.

Immune responses of neonates differ markedly to those of adults, with skewed cytokine phenotypes, reduced inflammatory properties and drastically diminished memory function. Recent research efforts have started to unravel the role of cellular metabolism in determining immune cell fate and function. For studies in humans, much of the work on metabolic mechanisms underpinning innate and adaptive immune responses by different haematopoietic cell types is in adults. Studies investigating the contribution of metabolic adaptation in the unique setting of early life are just emerging, and much more work is needed to elucidate the contribution of metabolism to neonatal immune responses. Here, we discuss our current understanding of neonatal immune responses, examine some of the latest developments in neonatal immunometabolism and consider the possible role of altered metabolism to the distinctive immune phenotype of the neonate. Understanding the role of metabolism in regulating immune function at this critical stage in life has direct benefit for the child by affording opportunities to maximize immediate and long-term health. Additionally, gaining insight into the diversity of human immune function and naturally evolved immunometabolic strategies that modulate immune function could be harnessed for a wide range of opportunities including new therapeutic approaches.

Spatial variation in the gastrointestinal microbiome, diet, and nutritional condition of a juvenile flatfish among coastal habitats

Gut microbiota are important for the health, fitness and development of animal hosts, but little is known about these assemblages in wild populations of fish. Such knowledge is particularly important for juvenile life stages where nutritional intake critically determines early development, growth, and ultimately recruitment. We characterise the microbiome inhabiting the gut of young-of-the-year European plaice (‘YOY plaice’) on sandy beaches, their key juvenile habitat, and examine how these microbial communities vary spatially in relation to diet and nutritional condition of their plaice hosts. Body size, diet (stomach fullness and eukaryotic 18S ribosomal sequencing), nutritional condition (RNA:DNA) and gut microbiota (16S prokaryotic ribosomal sequencing) were compared in fish at two spatial scales: between beaches separated by 10s of kilometres and between sites at different depths on the same beach, separated by 10s of metres. The main microbial phyla in YOY plaice guts were Proteobacteria, Spirochaetes, Tenericutes and Verrucomicrobiae. Within the Proteobacteria there was an unusual dominance of Alphaproteobacteria. Differences in body size, diet and nutritional condition of YOY plaice between beaches were accompanied by differences in gut microbial assemblage structure. Notably, substantially reduced nutritional condition and size at one of the beaches was associated with lower stomach fullness, reduced consumption of annelids and differences in the abundance and presence of specific microbial taxa. Differences were also detected in microbial assemblages, body size, and diet between depths within the same nursery beach, although stomach fullness and nutritional condition did not vary significantly. The functional links between the environment, gut microbiota, and their hosts are potentially important mediators of the development of young fish through critical life stages. Our study indicates that these links need to be addressed at 10 km and even 10 m scales to capture the variability observed in wild populations of juvenile fish.

Movement patterns and activity levels are shaped by the neonatal environment in Antarctic fur seal pups

Tracking studies of juveniles are rare compared to those of adults, and consequently little is known about the influence of intrinsic and extrinsic factors on activity during this critical life stage. We used hourly GPS data, collected from 66 Antarctic fur seal pups from birth until moulting, to investigate the explanatory power of multiple individual-based and environmental variables on activity levels. Pups were sampled from two nearby breeding colonies of contrasting density during two subsequent years, and a two-state hidden Markov model was used to identify modalities in their movement behaviour, specifically ‘active’ and ‘inactive’ states. We found that movement was typified by central place exploration, with active movement away from and subsequent return to a location of inactivity. The probability of such directed exploration was unaffected by several factors known to influence marine mammal movement including sex, body condition, and temperature. Compared to pups born at the high-density colony, pups at low-density were more active, increased their activity with age, and transitioned earlier into the tussock grass, which offers protection from predators and extreme weather. Our study illustrates the importance of extrinsic factors, such as colony of birth, to early-life activity patterns and highlights the adaptive potential of movement.