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1. Spatial management of marine ecosystems requires detailed knowledge of spatio-temporal mechanisms linking physical and biological processes. Tidal currents, the main driver of ecosystem dynamics in temperate coastal ecosystems, influence predator foraging ecology by affecting prey distribution and ecology. The mechanistic links between tidal currents and how they influence predator-prey behaviour and interactions at a fine scale are poorly understood. 2. Studies of fine-scale changes in oceanography, prey and predator behaviour with tidal currents require repeated surveys of the same location over brief time-scales. Such data are highly temporally and spatially autocorrelated and require appropriate analytical tools. 3. We used functional data analysis (FDA), specifically functional principal component analysis (FPCA), to analyse repeated, fine-scale, survey data collected in the North Sea. FPCA was used to explore the relationship between the behaviour of an important North Sea prey species (sandeel Ammodytes spp.) and a vulnerable surface-foraging predator (black-legged kittiwake Rissa tridactyld) with fine-scale tidally driven changes in bio-physical characteristics (temperature stratification and maximum subsurface chlorophyll concentration). 4. The FPCA indicated that sandeels were aggregated close to the surface at maximum ebb (ME) currents. Surface-feeding kittiwakes were also found in highest numbers during ME in locations of both high subsurface chlorophyll concentration and shallow sandeel aggregations. We suggest that the combination of a well-stratified water column with the movement of tidal currents over uneven topography results in surface aggregations of sandeels which kittiwakes exploit. 5. Synthesis and applications. Functional Data Analysis provides a useful tool for examining spatio-temporal patterns in natural ecosystems. In combination with fine-scale repeated survey design, we identified the importance of tide in driving prey behaviour and hence predator foraging behaviour. This has implications both for critical marine habitat identification for Marine Protected Area selection and for fisheries stock assessments. We therefore recommend that tidal aspects should be taken into account when designing marine surveys in temperate coastal ecosystems both to ensure the best identification of critical marine habitat and to improve the accuracy offish stock assessments.

Background The use of biologging tags to answer questions in animal movement ecology has increased in recent decades. Pop-up satellite archival tags (PSATs) are often used for migratory studies on large fish taxa. For PSATs, movements are normally reconstructed from variable amounts of transmitted data (unless tags are recovered, and full data archives accessed) by coupling geolocation methods with a state-space modelling (SSM) approach. Between 2018 and 2019, we deployed Wildlife Computers PSATs (MiniPATs) from which data recovery varied considerably. This led us to examine the effect of PSAT data volume on SSM performance (i.e., variation in reconstructed locations and their uncertainty). We did this by comparing movements reconstructed using partial (< 100%) and complete (100%) geolocation data sets from PSATs and investigated the variation in Global Position Estimator 3 (GPE3; Wildlife Computers’ proprietary light-based geolocation SSM) reconstructed locations and their certainty in relation to data volume and movement type (maximum dispersal distance). Results In this analysis, PSATs ( n  = 29) deployed on Atlantic bluefin tuna ( Thunnus thynnus ) transmitted data after detaching from study animals for between 0.3 and 10.8 days (mean 4.2 ± 3 days), yielding between 2 and 82% (mean 27% ± 22%) of total geolocation data. The volume of geolocation data received was positively related to the amount of time a tag transmitted for and showed a weak negative relationship to the length of the tag deployment. For 12 recovered PSATs (i.e., 100% of geolocation data; mean ± 1 S.D. = 301 ± 90 days of data per fish), (i) if ABT travelled short-distances (< 1000 km), movements reconstructed from partial data sets were more similar to their complete data set counterpart than fish that travelled over longer distances (> 1000 km); (ii) for fish that travelled long distances, mean distance of locations from corresponding complete data set locations were inversely correlated with the volume of data received; (iii) if only 5% of data was used for geolocation, reconstructed locations for long-distance fish differed by 2213 ± 647 km from the locations derived from complete data sets; and, (iv) track reconstructions omitted migrations into the Mediterranean Sea if less than 30% of data was used for geolocation. Conclusions For Wildlife Computers MiniPATs in our specific application, movements reconstructed with as little as 30% of the total geolocation data results in plausible outputs from the GPE3. Below this data volume, however, significant differences of more than 2000 km can occur. Whilst for a single species and manufacturer, this highlights the importance of careful study planning and the value of conducting study-specific sensitivity analysis prior to inclusion of modelled locations in research outputs. Based on our findings, we suggest general steps and refinements to maximise the value of light geolocation data from PSATs deployed on aquatic animals and highlight the importance of conducting data sensitivity analyses.

Research on the direct effects of capture and tagging on post-release behaviour is typically limited to short-term deployments. To investigate the initial and longer-term behavioural responses to capture and tagging, we deployed eight Cefas G7 tags (1Hz depth and temperature, and 20 Hz triaxial acceleration) for 21–94 hours and 12 Wildlife Computers MiniPATs (depth, temperature, light and triaxial acceleration, each at 0.2 Hz) for 110–366 days on Atlantic bluefin tuna (ABT) in the English Channel. Post-release, ABT exhibited a strong, highly active initial swimming response, consistent with patterns reported in previous bluefin tuna, billfish and elasmobranch tracking studies. Accelerometry tags revealed that activity (VeDBA g), tailbeat amplitude (g) and dominant stroke frequency (Hz) were greater (2.4, 3.2 and 1.4 times respectively) within the first hour post-release than the subsequent 24 hours, stabilising at lower levels within 5–9 hours. However, lower resolution accelerometry data (0.2 Hz), obtained from longer periods from MiniPATs, revealed that fish then maintained this reduced activity for 11 ± 7.9 days (mean ± 1 SD; range: 2–26 days), during which they displayed disrupted diel patterns of activity and allocated on average 5 minutes of each day to burst energy events, compared to 14 minutes (max 74 minutes) during “recovered” periods. Subsequently, their activity levels increased again and were characterised by higher magnitude acceleration events (which may constitute feeding events) and became more active during the day than at night. Year-long deployments revealed that consistent diel vertical migration, diurnal patterns of activity, and increased time allocation to fast starts are normal for ABT off the British Isles in summer months, and their absence at the start of data collection may be related to the effect of capture and tagging, which may be longer lasting, and more complex than previously appreciated.

Bats inhabiting northern latitudes are faced with short reproductive seasons during which they must produce and rear pups before fattening up in time to survive the winter hibernation. Therefore, the timing of parturition has considerable impacts on future fitness prospects for the mother and pup. However, little is known about individual variation in breeding phenology and its consequences for postnatal development within bat populations. Here, we studied the phenology of breeding in Eptesicus nilssonii across 7 years using data collected by day‐to‐day monitoring of a breeding colony in Norway (60.1° N) for which the identity and age of each mother (N = 8) and pup (N = 28) were known. Using mixed‐effect models, we found that arrival at the colony was influenced by temperature conditions from mid‐April to mid‐May across all females, but that there were strong and consistent individual differences in arrival‐ and parturition time across years. Females generally arrived ~32.1 days before giving birth, but the gestation duration was reduced if females arrived late and prolonged if females left the colony when faced with cold weather conditions. Pups born later in the season were born smaller but had higher growth rates during the most rapid growth period (<10 days old). The within‐individual effects suggest that the higher growth rates could be due to mothers compensating (e.g. through increased food intake) for late parturition rather than by improved food availability. Date of parturition did not influence adult body size in pups. Pups became volant at the earliest only 13.1 days after birth and approached adult flight patterns during their first flight week. Our results suggest that E. nilssonii is highly adapted to a short breeding season by producing large, fast developing and early volant pups, despite the environmental pressures bats face at northern latitudes. Here, we studied individual‐level breeding phenology and postnatal development in Eptesicus nilssonii across 7 years, using data collected by day‐to‐day monitoring of a breeding colony in Norway. We show evidence of strong and consistent maternal differences in breeding phenology in bats across years. Our results further suggest that E. nilssonii is highly adapted to a short breeding season by producing large, fast‐developing, and early‐volant pups despite the environmental pressures bats face at northern latitudes.

Background In Europe, bat rabies is primarily attributed to European bat lyssavirus type 1 (EBLV-1) and European bat lyssavirus type 2 (EBLV-2) which are both strongly host-specific. Approximately thirty cases of infection with EBLV-2 in Daubenton’s bats ( Myotis daubentonii ) and pond bats ( M. dasycneme ) have been reported. Two human cases of rabies caused by EBLV-2 have also been confirmed during the last thirty years, while natural spill-over to other non-flying mammals has never been reported. Rabies has never been diagnosed in mainland Norway previously. Case presentation In late September 2015, a subadult male Daubenton’s bat was found in a poor condition 800 m above sea level in the southern part of Norway. The bat was brought to the national Bat Care Centre where it eventually displayed signs of neurological disease and died after two days. EBLV-2 was detected in brain tissues by polymerase chain reaction (PCR) followed by sequencing of a part of the nucleoprotein gene, and lyssavirus was isolated in neuroblastoma cells. Conclusions The detection of EBLV-2 in a bat in Norway broadens the knowledge on the occurrence of this zoonotic agent. Since Norway is considered free of rabies, adequate information to the general public regarding the possibility of human cases of bat-associated rabies should be given. No extensive surveillance of lyssavirus infections in bats has been conducted in the country, and a passive surveillance network to assess rabies prevalence and bat epidemiology is highly desired.

Aim: Studies focussing on long-term changes in squid populations are rare due to limited availability of fisheries-independent data. However, squid play an important role as predator and prey in marine food-webs and have also become an increasingly important target for fisheries. Their short life history is thought to make them particularly sensitive to changes in the environment, potentially leading to strong fluctuations in population size. Here, we investigate whether squid have increased in the North Sea, in terms of distribution and abundance, and whether these patterns are related to variability in environmental and climatic factors. Location: North Sea, north-east Atlantic Ocean. Methods: We extracted squid catches from a unique 35-year time series of bottom trawl survey data in the North Sea (1980-2014), collected during late summer (August-September). Changes in distribution and abundance were compared with climatic variables known to be linked with various ecosystem components in the area. Results: We found that squid distribution across the North Sea increased over the 35-year time series. Loligo expanded southward from a predominantly north-easterly distribution, compared to northward expansions by Alloteuthis and the Ommastrephidae from their core distributions in the southern and central North Sea respectively. In addition, all squid species studied here displayed an overall increase in biomass over the time series and there were large annual fluctuations. Significantly positive relationships were found between this increase and climate variables for each of the dominant individual taxa studied and when all species were combined. Main conclusions: The results suggest a strong causal relationship between climate variability, notably warming sea temperatures, and squid populations. At least for the last 35 years, climate change appears to have been largely favourable for squid and with changes in climate set to continue, squid may end up beneficiaries where many finfish struggle.

AIM: We investigated the effects of disease on the local abundances and distributions of species at continental scales by examining the impacts of white‐nose syndrome, an infectious disease of hibernating bats, which has recently emerged in North America. LOCATION: North America and Europe. METHODS: We used four decades of population counts from 1108 populations to compare the local abundances of bats in North America before and after the emergence of white‐nose syndrome to the situation in Europe, where the disease is endemic. We also examined the probability of local extinction for six species of hibernating bats in eastern North America and assessed the influence of winter colony size prior to the emergence of white‐nose syndrome on the risk of local extinction. RESULTS: White‐nose syndrome has caused a 10‐fold decrease in the abundance of bats at hibernacula in North America, eliminating large differences in species abundance patterns that existed between Europe and North America prior to disease emergence. White‐nose syndrome has also caused extensive local extinctions (up to 69% of sites in a single species). For five out of six species, the risk of local extinction was lower in larger winter populations, as expected from theory, but for the most affected species, the northern long‐eared bat (Myotis septentrionalis), extinction risk was constant across winter colony sizes, demonstrating that disease can sometimes eliminate numerical rarity as the dominant driver of extinction risk by driving both small and large populations extinct. MAIN CONCLUSIONS: Species interactions, including disease, play an underappreciated role in macroecological patterns and influence broad patterns of species abundance, occurrence and extinction.

Lesser sandeels Ammodytes marinus are eaten by a range of predatory fishes including commercially fished species, but are also exploited at large scale by industrial fisheries. Is availability of sandeels, as key prey source, linked to the body condition of predatory fishes? In the North Sea, the largest sandeel biomass is concentrated in the Dogger Bank region. Here we studied predator–sandeel interactions at two sites differing widely in sandeel abundance and local sandeel fishing effort. Surveys took place in 2004, 2005, and 2006, years when local sandeel densities observed at these sites were low, intermediate, and high, respectively. Five predator species––whiting, lesser weever, grey gurnard, plaice, and haddock––showed better body condition indices in either the years or study area (or both) characterised by higher local sandeel densities, when compared to sandeel-poorer conditions. Moreover, whiting, weever, and gurnard condition was better for those individuals actually observed to have eaten sandeels (based on stomach contents) than for those that had not. As body condition relates to growth, reproduction, and survival, predators in sandeel-rich conditions may be inferred to have a higher fitness. These links between sandeel availability, sandeel consumption, and predator condition hint that, if large-scale localised depletions of sandeels were to occur, negative indirect effects on predatory fish might become apparent, underlining the importance of considering the sandeel fishery in an ecosystem context.

Forest management rarely considers protecting bats in Fennoscandian regions although all species rely on forest habitat at some point in their annual cycle. This issue is especially evident as wind parks have increasingly been developed inside Fennoscandian forests, against the advice of international bat conservation guidelines. In this study, we aimed to describe and explain bat community dynamics at a Norwegian wind park located in a boreal forest, especially to understand potential avoidance or attraction effects. The bat community was sampled acoustically and described using foraging guilds (short, medium, and long‐range echolocators; SRE, MRE, LRE) as well as behavior (commuting, feeding and social calls). Sampling was undertaken at two locations per turbine: 1) the turbine pad and 2) a paired natural habitat at ground level, as well as from a meteorological tower. We used a recently developed method for camera trapping nocturnal flying insects synchronously with bat acoustic activity. Our results reveal trends in feeding and general bat activity across foraging guilds in relation to insect availability, habitat type, wind, temperature, and seasonality. We show how seasonal patterns in behavior across guilds were affected by habitat type, temperature, and wind. We found that SRE commuting and especially feeding activity was highest in natural habitats, whereas LRE overall activity at habitats more season dependent. We found that nocturnal insect availability was positively correlated with total bat feeding activity throughout the night. Our results provide evidence for both direct and indirect risks to bat communities by wind parks: SRE bat habitat is lost to wind energy infrastructure and LRE bat may have an increased risk of fatality. Our findings provide important insights on seasonal and spatial variability in bat activity, which can inform standardizing monitoring of bats acoustically in boreal forests, at wind parks, and in combination with non‐invasive insect monitoring.

Recent studies in the marine environment have suggested that the limited phenotypic plasticity of cold-adapted species such as Atlantic cod Gadus morhua L. will cause distributions to shift toward the poles in response to rising sea temperatures. Some cod stocks are predicted to collapse, but this remains speculative because almost no information is available on the thermal tolerance of cod in its natural environment. We used electronic tags to measure the thermal experience of 384 adult Atlantic cod from 8 different stocks in the northeast Atlantic. Over 100000 d of data were collected in total. The data demonstrate that cod is an adaptable and tolerant species capable of surviving and growing in a wide range of temperate marine climates. The total thermal niche ranged from –1.5 to 19°C; this range was narrower (1 to 8°C) during the spawning season. Cod in each of the stocks studied had a thermal niche of approximately 12°C, but latitudinal differences in water temperature meant that cod in the warmer, southern regions experienced 3 times the degree days (DD; ~4000 DD yr–1) than individuals from northern regions (~1200 DD yr–1). Growth rates increased with temperature, reaching a maximum in those cod with a mean thermal history of between 8 and 10°C. Our direct observations of habitat occupation suggest that adult cod will be able to tolerate warming seas, but that climate change will affect cod populations at earlier life-history stages as well as exerting effects on cod prey species.