Movements and spatial usage of harbour seals in the Elbe estuary in Germany.

Harbour seals are top predators in the North Sea and regarded as sentinels for ecosystem health. A few hundred also occur in adjacent estuaries, such as the Elbe estuary, Germany. However, only little is known about how these animals use this dynamic tidally influenced habitat, which has been under high anthropogenic pressure for decades.

Vessel noise exposures of harbour seals from the Wadden Sea.

The North Sea faces intense ship traffic owing to increasing human activities at sea. As harbour seals (Phoca vitulina) are abundant top predators in the North Sea, it is hypothesised that they experience repeated, high-amplitude vessel exposures. Here, we test this hypothesis by quantifying vessel noise exposures from deployments of long-term sound and movement tags (DTAGs) on nine harbour seals from the Wadden Sea.

Magnetic-Field-Induced Dielectric Anomalies in Cobalt-Containing Garnets.

Here we present a comparative study of the magnetic and crystal chemical properties of two Co containing garnets. CaYCoGeO (which has been reported previously) and NaCaCoVO both exhibit the onset of antiferromagnetic order around 6 K as well as field-induced transitions around 7 and 10 T, respectively, that manifest as anomalies in the dielectric properties of the material. We perform detailed crystal-chemistry analyses and complementary density functional theory calculations to show that very minor changes in the local environment of the Co ions explain the differences in the two magnetic structures and their respective properties.

Drivers and constraints on offshore foraging in harbour seals.

Central place foragers are expected to offset travel costs between a central place and foraging areas by targeting productive feeding zones. Harbour seals (Phoca vitulina) make multi-day foraging trips away from coastal haul-out sites presumably to target rich food resources, but periodic track points from telemetry tags may be insufficient to infer reliably where, and how often, foraging takes place. To study foraging behaviour during offshore trips, and assess what factors limit trip duration, we equipped harbour seals in the German Wadden Sea with high-resolution multi-sensor bio-logging tags, recording 12 offshore trips from 8 seals.

Assessing seal carcasses potentially subjected to grey seal predation.

In order to conduct an objective evaluation of potential ecological effects of grey seal predation on marine mammals, it is essential to establish a broad knowledge base helping in the thorough identification of such cases during post-mortem examination. The aim of this work is to report and discuss outcomes resulting from a retrospective evaluation of harbour (Phoca vitulina) and grey seal (Halichoerus grypus) stranding and necropsy data (n = 3274). In addition, the results are compared to a recent case of definite grey seal predation from Germany as well as reports from other countries.