The influence of prey distribution on marine top predator movements

Predation is an ecological process that relies on spatial and temporal co-occurrence of predators and their prey. In marine ecosystems, killer and humpback whales are considered sentinels of ecosystem health, given their critical roles as top predators in shaping marine food webs and their responsiveness to ecosystem changes. As they are seldom influenced by natural threats, they are model species for the study of predator-prey dynamics since their movements, as observed by multidimensional biotelemetry, can reveal interactions occurring underwater and out of sight. This thesis is comprised of three papers that investigate how various prey influences the movements of killer and humpback whales within the Norwegian and Barents Seas. Paper I combined herring density data with whale satellite telemetry to explore how killer whale movements respond to patchy distributions of Norwegian spring spawning herring. This revealed that killer whales follow herring along the Norwegian coast, adjusting their movements in response to herring density. Paper II examined movement differences associated with Norwegian killer whale seal predation as compared to fish predation. Differences in travel routes, shore proximity, and directionality towards seal haul-out areas were observed, emphasizing how these predators optimize their foraging strategies for their prey. Paper III investigated how humpback whale horizontal and vertical movements were influenced by capelin density in the Barents Sea. Both lateral and vertical whale movements responded to capelin density variations, highlighting their tendency to target the densest prey aggregations on both horizontal and vertical scales. Collectively, this thesis revealed nuanced foraging movements in response to varying prey distributions, underscoring the need for more comprehensive models to account for the complexities of predator-prey dynamics, particularly in the face of the rapidly changing Arctic marine ecosystems. It also serves as a foundation for future research incorporating finer-scale biologging tags to connect prey distribution with predator movements.Predasjon er en økologisk prosess hvor et dyr spiser et annet. Hvor mye som kan spises avhenger både av tid og sted og hvor mye overlapp i tid og rom det er mellom rovdyret og byttedyrene. Spekkhoggere og knølhval er på toppen av den marine næringskjeden, såkalte toppredatorer. Disse påvirkes derfor av endringer som skjer nedover i næringskjeden i økosystemene. Derfor kan de også være gode indikatorer til helsestatusen på økosystemene. Siden toppredatorer har få naturlige fiender, er de gode modellarter for å studere dynamikken mellom rovdyr og byttedyr. Ny sporingsteknologi muliggjør nå at vi kan «spionere» på disse dyrene ved hjelp av såkalt «satelittmerker» som festes til dyret. Da kan vi følge disse kontinuerlig via signaler som sendes til satellitter inntil merket faller av. Vi kan da beskrive adferden og bevegelsene til dyrene kontinuerlig både over og under vann, uten å selv måtte observere dem. Gjennom tre studier bruker denne doktorgrads avhandlingen slik sporingsteknologi og innsamlet informasjon om byttedyrtetthet til å undersøke hvordan bevegelsene til spekkhoggere langs norskekysten og knølhvaler i Barentshavet blir påvirket av byttedyrene deres. Det første studiet sammenligner data om tetthet av norsk vårgytende sild langs norskekysten med vandringene til merkede spekkhoggere for å studere hvordan disse hvalenes bevegelser påvirkes av silda. Resultatene viste at spekkhoggere var veldig gode til å finne de høyeste tetthetene av silda når denne flytter seg langs norskekysten. Jo mer sild, jo mere spekkhoggere. Derfor kan også disse hvalene brukes som «forskningsassistenter» for å indirekte beskrive forandringer i silda sin vandring over tid. I det andre studiet undersøkte vi bevegelsesmønsteret til spekkhoggere som jaktet på sel deler av året. Her ble vandringene til disse selspisende spekkhoggerne sammenlignet med sildespisende spekkhoggere i samme tidsrom. Resultatene viste at de selene som jaktet sel gjorde dette tett opptil kysten og ofte i retning mot de kjente hvileplasser til sel. Til forskjell oppholdt de sildespisende spekkhoggerne mest i åpent farvann lengre fra kysten, noe som viser hvordan disse rovdyrene til enhver tid tilpasser sine bevegelser i forhold til byttet de jakter på. I det siste studiet undersøkte vi hvordan den horisontale bevegelsen i havet og dykkingen til knølhval ble påvirket av loddetettheten i Barentshavet. Resultatene viste at også kvølhvalen var svært god til enhver tid å finne områdene med høyest tetthet av byttedyret sitt. Dette gjorde den både horisontalt over store områder og i forhold til dybde gjennom døgnet, dvs. når lodda sto dypt om dagen og høyt i vannsøyla om natta. Samlet viser denne avhandlingen at begge hvalartene er svært gode til å finne områder med høy tetthet av byttedyr, som viser hvordan vi ved hjelp av ny teknologi og avanserte modeller bedre kan forstå hvordan forholdet mellom rovdyr og byttedyr fungerer. Ved å studere vandringene til hval får vi derfor også indirekte viktig informasjon om fordelingen av byttedyrene til hvalene, dyr som ofte er nøkkelarter i økosystemene og derfor påvirker alle ledd både ned og opp i næringskjeden, helt fra mikroskopiske plankton til store toppredatorer som hval. Dette er også viktige data til å danne et godt grunnlag for å undersøke og forutsi hvordan endringer i de nordlige marine økosystemene vil kunne forandres over tid, eksempelvis hvordan klimaendringer, fiskeri og annen menneskelige aktivitet påvirker økosystemene fra bunn til topp i næringskjeden. I tillegg hjelper slike data oss med å påvise viktige områder for toppredatorer gjennom året og dermed også sannsynliggjøre hvor menneskelig aktivitet vil kunne ha størst påvirkning på disse dyrene

The preparation, training and support requirements of expatriate trailing spouses

BACKGROUND : Decades have passed since trailing spouses were first identified as the primary causes of expatriate failure. This has led to numerous studies to determine how best to avoid such failures. In particular, it was determined that through the preparation, training and support of trailing spouses multinational enterprises (MNEs) can not only assist with their adjustment to the host country, but also reduce the likelihood of expatriate failure. AIM : With the impact of the trailing spouse still being a major concern for the success of an international assignment decades after it was first identified as such, this research aimed to determine the preparation, training and support requirements of trailing spouses prior to, and during an international assignment. SETTING : The article includes the responses from trailing spouses who at the time of the study were on assignment in 52 countries on six continents. METHODS : Both non-probability judgement sampling and snowball sampling were used to identify the 218 respondents who completed a self-administered questionnaire which respondents were able to access online. The data was then analysed using exploratory factor analysis, Cronbach’s alpha, a t-test and paired t-test. RESULTS : Statistically significant differences were found between the preparation, training and support required by trailing spouses and what was offered to them by MNEs for all the specific forms of preparation, training and support measured in this study. CONCLUSION : MNEs are still falling short of the preparation, training and support needs of trailing spouses. In particular, MNEs seem to focus on some operational aspects of spousal adjustment while the social aspects are still not sufficiently addressed.National Research Foundation of South Africahttp://www.sajems.orghj2020Business Managemen

Predation research with electronic tagging

Predation is a fundamental aspect of ecology that drives ecosystem structure and function. A better understanding of predation can be facilitated by using electronic tags that log or transmit positions of predator or prey species in natural settings, however, there are special considerations that must be made to avoid biased estimates. We provide an overview of the tools available for studying predation with electronic tags including the tag types and analytical tools that can be used to identify where, when and how prey are killed by predators. We also discuss considerations for experimental design when studying predation using electronic tags, including how to minimize effects of capture and tagging procedures. Ongoing innovation and integration of sensors for tags will provide more detailed data about the performance of tagged predators and the fate of tagged prey. Where analysts can effectively resolve the timing of predation using state-of-the-art tags and analytical tools, we foresee exciting advances in our understanding of animal demographics, evolutionary trajectories and management systems. Prospects to develop new tools and approaches for tracking predation while designing studies to more effectively limit bias are an important frontier for understanding ecosystems and addressing human–wildlife conflicts. Given great uncertainties about environmen-tal change and intensifying conflicts between humans and predators, effective study designs integrating electronic tagging to study predation have a promising future in fundamental and applied ecologypublishedVersio

Determination of zeta potential via nanoparticle translocation velocities through a tunable nanopore: using DNA-modified particles as an example

Here we use a polyurethane tunable nanopore integrated into a resistive pulse sensing technique to characterize nanoparticles surface chemistry via the measurement of particle translocation velocities, which can be used to determine the zeta potential of individual nanoparticles

A deep dive into fat: Investigating blubber lipidomic fingerprint of killer whales and humpback whales in northern Norway

In cetaceans, blubber is the primary and largest lipid body reservoir. Our current understanding about lipid stores and uses in cetaceans is still limited, and most studies only focused on a single narrow snapshot of the lipidome. We documented an extended lipidomic fingerprint in two cetacean species present in northern Norway during wintertime. We were able to detect 817 molecular lipid species in blubber of killer whales (Orcinus orca) and humpback whales (Megaptera novaeangliae). The profiles were largely dominated by triradylglycerols in both species and, to a lesser extent, by other constituents including glycerophosphocholines, phosphosphingolipids, glycerophosphoethanolamines, and diradylglycerols. Through a unique combination of traditional statistical approaches, together with a novel bioinformatic tool (LION/web), we showed contrasting fingerprint composition between species. The higher content of triradylglycerols in humpback whales is necessary to fuel their upcoming half a year fasting and energy-demanding migration between feeding and breeding grounds. In adipocytes, we assume that the intense feeding rate of humpback whales prior to migration translates into an important accumulation of triacylglycerol content in lipid droplets. Upstream, the endoplasmic reticulum is operating at full capacity to supply acute lipid storage, consistent with the reported enrichment of glycerophosphocholines in humpback whales, major components of the endoplasmic reticulum. There was also an enrichment of membrane components, which translates into higher sphingolipid content in the lipidome of killer whales, potentially as a structural adaptation for their higher hydrodynamic performance. Finally, the presence of both lipid-enriched and lipid-depleted individuals within the killer whale population in Norway suggests dietary specialization, consistent with significant differences in δ15N and δ13C isotopic ratios in skin between the two groups, with higher values and a wider niche for the lipid-enriched individuals. Results suggest the lipid-depleted killer whales were herring specialists, while the lipid-enriched individuals might feed on both herrings and seals

Foraging movements of humpback whales relate to the lateral and vertical distribution of capelin in the Barents Sea

Understanding how individual animals modulate their behaviour and movement patterns in response to environmental variability plays a central role in behavioural ecology. Marine mammal tracking studies typically use physical environmental characteristics that vary, and/or proxies of prey distribution, to explain predator movements. Studies linking predator movements and the actual distributions of prey are rare. Here we analysed satellite tag data from ten humpback whales in the Barents Sea (north-east Atlantic) to examine how their spatial movement and dive patterns are influenced by the geographic and vertical distribution of capelin, which is a key prey species for humpback whales. We used capelin density estimates based on direct observations from a trawl-acoustic survey and sun elevation to explore the drivers of changes in movement patterns. We found that the humpback whales’ exhibited characteristic area restricted search movement where capelin density was the highest. While horizontal movements showed both positive and negative individual relationships with sun elevation, humpback whale dive depth was positively correlated with diurnal variations in the vertical distribution of capelin. This suggests that in addition to whales foraging in regions of high capelin density, they also target the densest shoals of capelin at a range of depths, throughout the day and night. Overall, our findings suggest that regions of high capelin density are important foraging grounds for humpback whales, highlighting the central role capelin plays in the Barents Sea marine ecosystem

Fine-mapping identifies multiple prostate cancer risk loci at 5p15, one of which associates with TERT expression

Associations between single nucleotide polymorphisms (SNPs) at 5p15 and multiple cancer types have been reported. We have previously shown evidence for a strong association between prostate cancer (PrCa) risk and rs2242652 at 5p15, intronic in the telomerase reverse transcriptase (TERT) gene that encodes TERT. To comprehensively evaluate the association between genetic variation across this region and PrCa, we performed a fine-mapping analysis by genotyping 134 SNPs using a custom Illumina iSelect array or Sequenom MassArray iPlex, followed by imputation of 1094 SNPs in 22 301 PrCa cases and 22 320 controls in The PRACTICAL consortium. Multiple stepwise logistic regression analysis identified four signals in the promoter or intronic regions of TERT that independently associated with PrCa risk. Gene expression analysis of normal prostate tissue showed evidence that SNPs within one of these regions also associated with TERT expression, providing a potential mechanism for predisposition to disease

Disaster Risks Research and Assessment to Promote Risk Reduction and Management

Natural hazard events lead to disasters when the events interact with exposed and vulnerable physical and social systems. Despite significant progress in scientific understanding of physical phenomena leading to natural hazards as well as of vulnerability and exposure, disaster losses due to natural events do not show a tendency to decrease. This tendency is associated with many factors including increase in populations and assets at risk as well as in frequency and/or magnitude of natural events, especially those related to hydro-meteorological and climatic hazards. But essentially disaster losses increase because some of the elements of the multidimensional dynamic disaster risk system are not accounted for risk assessments. A comprehensive integrated system analysis and periodic assessment of disaster risks at any scale, from local to global, based on knowledge and data/information accumulated so far, are essential scientific tools that can assist in recognition and reduction of disaster risks. This paper reviews and synthesizes the knowledge of natural hazards, vulnerabilities, and disaster risks and aims to highlight potential contributions of science to disaster risk reduction (DRR) in order to provide policy-makers with the knowledge necessary to assist disaster risk mitigation and disaster risk management (DRM)

Adaptation of pineal expressed teleost exo-rod opsin to non-image forming photoreception through enhanced Meta II decay

Photoreception by vertebrates enables both image-forming vision and non-image-forming responses such as circadian photoentrainment. Over the recent years, distinct non-rod non-cone photopigments have been found to support circadian photoreception in diverse species. By allowing specialization to this sensory task a selective advantage is implied, but the nature of that specialization remains elusive. We have used the presence of distinct rod opsin genes specialized to either image-forming (retinal rod opsin) or non-image-forming (pineal exo-rod opsin) photoreception in ray-finned fish (Actinopterygii) to gain a unique insight into this problem. A comparison of biochemical features for these paralogous opsins in two model teleosts, Fugu pufferfish (Takifugu rubripes) and zebrafish (Danio rerio), reveals striking differences. While spectral sensitivity is largely unaltered by specialization to the pineal environment, in other aspects exo-rod opsins exhibit a behavior that is quite distinct from the cardinal features of the rod opsin family. While they display a similar thermal stability, they show a greater than tenfold reduction in the lifetime of the signaling active Meta II photoproduct. We show that these features reflect structural changes in retinal association domains of helices 3 and 5 but, interestingly, not at either of the two residues known to define these characteristics in cone opsins. Our findings suggest that the requirements of non-image-forming photoreception have lead exo-rod opsin to adopt a characteristic that seemingly favors efficient bleach recovery but not at the expense of absolute sensitivity

Inspiring the Next Generation: Challenges and Strategies for Onboarding and Retention in an Undergraduate CubeSat Design Team

The University of Toronto Aerospace Team (UTAT) Space Systems Division is a fully student levy-funded, student-led undergraduate design team that develops CubeSats with research-oriented payloads. UTAT’s mission is to provide undergraduate students with unique opportunities to develop engineering design skills outside of the classroom, and therefore has a distinct focus on member growth and education. As an undergraduate student team, UTAT faces a unique set of challenges in onboarding members and maintaining a strong knowledge base on the team. These challenges include onboarding members with limited technical experience, equipping them with satellite design skills, and maintaining high interest levels among volunteer members with limited time to contribute. The team has implemented a wide range of strategies related to onboarding and member development over the past two years. Notable examples include hosting workshops and regular work sessions, and employing practice projects for technical skill development. This paper presents these practices in depth and evaluates their impacts using both quantitative and qualitative metrics of team success including retention rates, team demographic data, and individual perceptions of team dynamics. It also evaluates these practices against scientifically backed models, while evaluating the effectiveness of these models in the student team environment. Lessons learned include the importance of emphasizing a culture of inclusivity and psychological safety as well as utilizing workshops and skill-building modules both in the onboarding phase and throughout the year to generate and maintain interest in the team. The practices presented here are relevant and transferable to similar organizations including student teams, industry projects, and research initiatives