Seasonal distribution and dive behaviour of harp seals (<Emphasis Type="Italic">Pagophilus groenlandicus</Emphasis>) of the White Sea–Barents Sea stock

Eight adult female harp seals (Pagophilus groenlandicus) of the White Sea–Barents Sea stock were tagged with satellite-linked dive recorders during the nursing period and followed from breeding in late February 1995 until moulting in late April 1995. Another ten adult harp seals of both sexes were tagged and followed from moult in early May 1996 until breeding in late February the following year. Between breeding and moult the seals were distributed along the coasts of Kola of Russia and eastern Finnmark of Norway, coinciding in time and space with the spawning capelin (Mallotus villosus). Between moulting and breeding they encircled the entire Barents Sea, mostly in open water, using the water column from 20 to 300 m, and in so doing by and large reflecting the annual migrations of the capelin. Capelin is therefore assumed to be the main source of prey for the White Sea–Barents Sea stock of harp seals, to be substituted, in part, by amphipods (e.g. Themisto libellula) in mid-summer and polar cod (Boreogadus saida) and herring (Clupea pallasii) in late autumn and winter. These data provide a baseline for the evaluation of the effects of future climatic change in the rich Barents Sea ecosystem.     

Movement patterns and water quality preferences of juvenile bull sharks (<Emphasis Type="Italic">Carcharhinus leucas</Emphasis>) in a Florida estuary

Acoustic telemetry was used to examine the size of daily activity space, small-scale movement patterns, and water quality preferences of juvenile bull sharks in the Caloosahatchee River, Florida. Movement pattern analysis included rate of movement, swimming depth, linearity, direction, tidal influence, diel pattern, and correlation with environmental variables. Manual tacking occurred before and after a large freshwater influx which divided the sharks into two groups based on movement patterns. The first group displayed increased rate of movement, distance traveled, and space utilization at night, and movements correlated with salinity, temperature, and dissolved oxygen. The second group had an increased rate of movement, distance traveled, and space utilization during the day, and movements correlated with temperature, dissolved oxygen, turbidity and pH. These juvenile bull sharks displayed distinct diel movement patterns that were influenced by physical factors, which may account for the distribution of this top-level predator in the Caloosahatchee River.     

The effects of interpolation error and location quality on animal track reconstruction

The Global Positioning System (GPS) gives precise estimates of location. However, the investigation of animal movement and behavior often requires interpolation to examine events between such fixes. We obtained 6,288 GPS locations from an electronic tag deployed for 170 d on an adult male gray seal ( Halichoerus grypus ) that ranged freely off the east coast of Scotland, and interpolated between subsamples of these data to investigate the growth of uncertainty within the intervals between observations. Average uncertainty over the path increased linearly as the interval between interpolating locations increased, reaching 12 km in longitude and 6 km in latitude at 2-d separation. The decrease in precision caused by duty-cycling, only collecting data in part of the day, was demonstrated. Adding noise to the GPS locations to simulate data from the ARGOS satellite system had little effect on the total errors for observations separated by more than 12 h. While the rate of growth in interpolation error is likely to vary between species, these results suggest that frequent, and preferably evenly spaced, location fixes are required to take full advantage of the precision of GPS data in the reconstruction of animal tracks.     

Development of Exposure Characterization Regions for Priority Ambient Air Pollutants

To evaluate the relationship between air pollution and morbidity and mortality in epidemiological studies, the exposure of populations must be defined. Generally, ambient air monitoring networks are the source of the exposure data for these studies. In this study, we developed methods to define population exposure regions that represent minimal variation in air pollutant concentrations. We evaluated the spatial and temporal variation in concentrations for particulate matter less than 2.5 μm (PM_2.5) and 10 μm (PM₁₀) and ozone (O₃) across New York State. The results from the PM_2.5 and ozone analysis indicate a significant degree of regional transport and showed regions of consistent concentrations of 100 and 50 miles, respectively, around each monitor. PM₁₀ analysis indicated little temporal and spatial variation for this pollutant and larger regions were adopted. The exposure characterization regions for PM_2.5, PM₁₀, and ozone have been used in ecological epidemiological investigations by the New York State Department of Health. This work was conducted under the Environmental Public Health Tracking grant from the Centers for Disease Control and Prevention.     

Distribution and diversity of the enterococcal surface protein (esp) gene in animal hosts and the Pacific coast environment

Aims:  This study sought to evaluate the distribution of the enterococcal surface protein ( esp ) gene in Enterococcus faecium in the Pacific coast environment as well as the distribution and diversity of the gene in Northern California animal hosts.
Methods and Results:  Over 150 environmental samples from the Pacific coast environment (sand, surf zone, fresh/estuarine, groundwater, and storm drain) were screened for the esp gene marker in E. faecium , and the marker was found in 37% of the environmental samples. We examined the host specificity of the gene by screening various avian and mammalian faecal samples, and found the esp gene to be widespread in nonhuman animal faeces. DNA sequence analysis performed on esp polymerase chain reaction amplicons revealed that esp gene sequences were not divergent between hosts.
Conclusions:  Our data confirm recent findings that the E. faecium variant of the esp gene is not human-specific.
Significance and Impact of the Study:  Our results suggest that the use of the esp gene for microbial source tracking applications may not be appropriate at all recreational beaches.     

The movement of African elephants in a human-dominated land-use mosaic

Land outside of gazetted protected areas is increasingly seen as important to the future of elephant persistence in Africa. However, other than inferential studies on crop raiding, very little is understood about how elephants Loxodonta africana use and are affected by human-occupied landscapes. This is largely a result of restrictions in technology, which made detailed assessments of elephant movement outside of protected areas challenging. Recent advances in radio telemetry have changed this, enabling researchers to establish over a 24-h period where tagged animals spend their time. We assessed the movement of 13 elephants outside of gazetted protected areas across a range of land-use types on the Laikipia plateau in north-central Kenya. The elephants monitored spent more time at night than during the day in areas under land use that presented a risk of mortality associated with human occupants. The opposite pattern was found on large-scale ranches where elephants were tolerated. Furthermore, speed of movement was found to be higher where elephants were at risk. These results demonstrate that elephants facultatively alter their behaviour to avoid risk in human-dominated landscapes. This helps them to maintain connectivity between habitat refugia in fragmented land-use mosaics, possibly alleviating some of the potential negative impacts of fragmentation. At the same time, however, it allows elephants to penetrate smallholder farmland to raid crops. The greater the amount of smallholder land within an elephant's range, the more it was utilized, with consequent implications for conflict. These findings underscore the importance of (1) land-use planning to maintain refugia; (2) incentives to prevent further habitat fragmentation; (3) the testing and application of conflict mitigation measures where fragmentation has already taken place.     

Detection of single quantum dots in model organisms with sheet illumination microscopy

Single-molecule detection and tracking is important for observing biomolecule interactions in the microenvironment. Here we report selective plane illumination microscopy (SPIM) with single-molecule detection in living organisms, which enables fast imaging and single-molecule tracking and optical penetration beyond 300 μm. We detected single nanocrystals in Drosophila larvae and zebrafish embryo. We also report our first tracking of single quantum dots during zebrafish development, which displays a transition from flow to confined motion prior to the blastula stage. The new SPIM setup represents a new technique, which enables fast single-molecule imaging and tracking in living systems.     

Twenty-four hours in the life of Zingel asper

For the first time, radio-tracking observations were made over 24 h cycles during the growing season to quantify the habitat use and home range of Zingel asper , a critically endangered fish species, endemic to the Rhône River with a high risk of extinction (IUCN). New advances in radio telemetry with regard to the size of tags provided an opportunity to collect behavioural and habitat use information while remaining non-lethal. Zingel asper was characterized by small ranges of habitat use and, contrary to previous assumptions, the species was diurnal as illustrated by a smaller home range during the night than during daytime.     

Animal migration: linking models and data beyond taxonomic limits

An international workshop on animal migration was held at the Lorentz Center in Leiden, The Netherlands, 2–6 March 2009, bringing together leading theoreticians and empiricists from the major migratory taxa, aiming at the identification of cutting-edge questions in migration research that cross taxonomic borders.