Research

Funding: Industry (Feed manifacturing) , 22.000 EUR

Funding: Nationalparkstiftung Schleswig-Holstein, 22.500 EUR

Project Details:
The native harbor seal population has been severely depleted in the past, but rebounded after the end of hunting in the 1970s. Two seal distemper epidemics in 1988 and 2002 and an influenza epidemic drastically reduced the seal population in the Wadden Sea within a very short time. However, the population recovered each time, so that currently there are an estimated 40800 living in the Wadden Sea of the Netherlands, Germany and Denmark.
Despite the high profile of this species, some aspects of harbor seal ecology, such as precise movement patterns and habitat use in the Wadden Sea National Park and adjacent waters, as well as information on feeding ecology, are poorly studied. The few studies available suggest that harbor seals do make extended hunting excursions into the open North Sea. However, the ecological relevance of these excursions and the detailed, spatiotemporal resolution of foraging activity are based on purely theoretical approaches. Furthermore, it is not clear which prey organisms and prey size the seals prefer on their hunting trips and whether they show specific hunting tactics depending on prey size.
Therefore, this project aims to fill gaps in our knowledge about where, how often and what exactly seals feed on in the German North Sea.
A problem in this context is that seals spend most of their lives in the water, where it is very difficult to observe their movements. In this context, telemetry - i.e., the tagging of animals with small electronic devices - is an important method to obtain knowledge about habitat use and behavior of the animals. However, in terms of determining foraging and food acquisition, telemetry has a large element of uncertainty. While sensors can provide high-resolution movement data (geographic position, dive depth, dive length, dive distance, acceleration), a characterization of foraging behavior is usually based on a subjective assessment of theoretical assumptions. A direct observation of the feeding behavior can only be achieved by a camera directly on the animal. In the present project, seals will therefore be equipped with a special underwater camera ("CATS-Cam"). In the future, the knowledge gained can also serve as a basis for the optimization of management concepts, as well as for further studies, for example to validate data from conventionally used telemetry devices. Furthermore, the recorded videos can be used for public relations and environmental education.

Results:

In the present project, two seals were caught and equipped with special underwater cameras ("CATS-Cam"). As expected, the cameras detached from the animals after a few days and the stored video files could be read out and analysed. A first analysis showed that the concept was suitable for the study purposes. A total of 495 videos (total length of 21.8 hours) were recorded.

Further investigations will be carried out in the future to optimise the method, so that more data can be recorded and movement patterns that could be identified from the existing videos can be used as a template for further identifications in the movement data. Also, problems such as poor lighting conditions caused by high concentrations of suspended matter in the water are to be avoided through modifications to the device.

In the future, the further development of this method should also serve as a basis for optimising management concepts, for example to validate data from conventionally used telemetry devices.

https://www.tiho-hannover.de/universitaet/aktuelles-veroeffentlichungen/pressemitteilungen/detail/seehunden-ueber-die-schulter-schauen

Funding: Ministerium für Energiewende,Landwirtschaft, Umwelt, Natur und Digitalisierung des Landes Schleswig-Holstein, 53.000 EUR

Project Details:
Originally situated in east asia the racoon dog was introduced 1928 as a fur animal in the former soviet union. Since then the racoon dog spread continously west and inhabited new areas. In the late 1990 the first reproduction of racoon dogs in Schleswig- Holstein was recorded.

1927 racoons were released in the state of Hessen, in the following years other racoon dogs were set free or escaped form captivity in different parts of Germany. From this time on a free roaming population established. In 1975 the first reproduction of racoons was recorded in Schleswig- Holstein.

In our project we want to analyse the influence and the risk of these alien species on our native fauna. Therefore we want to asses the health status, especially the occurance of zoonotic and infectious diseases and the nutrition of the animals.

Shot animals or animals found dead are getting dissected at the institute for terrestrial and aquatic wildlife research of the TiHo Hannover. Samples for bacteriological, virological and parasitological diagnostics are taken and stomach content analysis and age determination is taking place. Based on the first results follow- up studies on the influence on native animal species and as a result of those a future long-term management can be developed

Results:

Malicious Mites?Sarcoptes scabiei in Raccoon Dogs (Nyctereutes procyonoides) in Schleswig-Holstein, Germany

https://www.mdpi.com/2076-0817/12/12/1379

Funding: Aarhus University, DK, 9.736 EUR

Project Details:
In 2021, data on the abundance and distribution of marine mammals were to be collected as part of an environmental impact assessment. The study area is located in the Kattegat near the Danish island of Hesselø. A new offshore wind farm is to be built there. The main target species of the present survey was the harbour porpoise (Phocoena phocoena).
The flight surveys were conducted by Aarhus University and followed the line transect method. In total, the area was surveyed three times in 2021. ITAW was commissioned by Aarhus University to accompany the planning and organisation of the new survey and to quality assure and evaluate the collected data.

Results:

For the three surveys of the study area, densities and abundances of harbour porpoises were estimated and the inaccuracies (95% confidence intervals and coefficient of variation (CV)) associated with the estimation were determined. The processed data and results were submitted to the client.

Funding: MELUND, 19.177 EUR

Project Details:
Since 2002, ITAW has been conducting flight-based surveys for harbour porpoises in the EEZ and the 12sm zone of the North Sea. A dedicated monitoring of harbour porpoises in the North Sea and Baltic Sea has been carried out in projects of the Federal Agency for Nature Conservation (BfN) since 2008. Within the framework of this survey and monitoring, valuable data series on the spatio-temporal occurrence and density of harbour porpoises could be collected including the area of the whale sanctuary in the Schleswig-Holstein Wadden Sea National Park.
ITAW also has proven expertise in bioacoustics and acoustic monitoring of cetaceans. Click Detectors (C-PODs) have already been used in numerous projects to study harbour porpoise habitat use and the effects of offshore wind farm construction and operation on harbour porpoises. The LKN POD monitoring has been operated by ITAW since 2011 and valuable data on acoustic harbour porpoise activity could also be collected in the area of the whale sanctuary in the Schleswig-Holstein Wadden Sea.
The aim of the project is to evaluate the whale sanctuary in terms of occurrence, abundance, seasonality and importance of the whale sanctuary as a habitat for harbour porpoises for feeding and as a calving and breeding area.
For this purpose, the following data sources are to be evaluated in depth:
a) Dedicated visual surveys to record harbour porpoise abundance in the German North Sea (12 nm plus EEZ);
b) Modelled density area maps to determine model-based abundance;
c) Acoustic monitoring of harbour porpoises using stationary click detectors (C-PODs) in the Wadden Sea.

Results:

Abschlußbericht im Auftrag des Landesbetriebes für Küstenschutz, Nationalpark und Meeresschutz Schleswig-

Holstein (LKN.SH) und des Ministeriums für Energiewende, Klimaschutz, Umwelt und Natur

(MEKUN)

https://www.tiho-hannover.de/fileadmin/57_79_terr_aqua_Wildtierforschung/79_Buesum/downloads/Berichte/Walschutzgebiet_Bericht_ITAW_20221012_final.pdf

Funding: Ministerium für Energiewende,Landwirtschaft, Umwelt, Natur und Digitalisierung des Landes Schleswig-Holstein, 20.000 EUR

Project Details:
Especially during sensitive life stages, i. e. the upbringing of offspring, predators can have a negative influence on their prey. This pilot study therefore aims to record and compare the spatiotemporal behavior of predator and their prey species. One focus hereby is the relevance of permanent landscape structures such as hedges as well as additionally created elements such as wildflower strips or fallow land.
Predators like the red fox (Vulpes vulpes) and the non-indigenous racoon dog (Nyctereutes procyonoides) as well as the European hare (Lepus europaeus) as a prey species occur in Schleswig-Holstein. To conduct the pilot study, individuals of these species are equipped with tags automatically collecting GPS data. Furthermore, the tags record spatial movements of the individual on three axes. With the received data, individual home ranges, nightly activities, and daily resting areas can be analysed. Eventually, captured patterns can be compared to identify overlaps between predators and their prey as well as the influence of structural landscape elements.

Results:

Abschlußbericht

https://www.tiho-hannover.de/fileadmin/57_79_terr_aqua_Wildtierforschung/79_Buesum/downloads/Berichte/2021_Praedatorenbericht.pdf

Funding: Aarhus University, DK, 4.451 EUR

Project Details:
On behalf of Aarhus University (Denmark), data on the abundance and distribution of marine mammals has been collected annually since 2012. Five Natura 2000 sites in the Danish North Sea and Skagerrak were surveyed in 2020. The main target species was the harbour porpoise (Phocoena phocoena). The flight surveys were conducted by Aarhus University and followed the line transect survey method. ITAW was commissioned to quality assure and evaluate the data collected. For the individual study areas, densities and abundances of harbour porpoises could be estimated and the inaccuracies (95% confidence intervals and coefficient of variation (CV)) associated with the estimation were determined. The processed data and results were submitted to the client.

Results:

Report of the Aarhus University (Denmark)

Videnskabelig rapport fra DCE - Nationalt Center for Miljø og Energi nr. 475

https://dce2.au.dk/pub/SR475.pdf

Funding: UKSH, Institut für Toxikologie und Pharmakologie für Naturwissenschaftler, Kiel, 8.404 EUR

Project Details:
Samples of bycaught common eiders from the danish Baltic Sea, which undergo post-mortem examinations at the Institute for Terrestrial and Aquatic Wildlife Research, are provisioned for toxicological analysis at the Christian-Albrechts-University Kiel.
At the Institute for Toxicology and Pharmacology for Natural Scientists, organ samples of liver, kidneys, muscle, brain and fat as well as bile are analysed for residues of explosive compounds of dumped munition. These are 2,4,6-Trinitrotoluene (TNT) and its derivates, which have been detected in blue mussels (Mytilus edulis) in other studies. The examination of common eider tissues will allow to draw conclusions about possible accumulation in the trophic chain.

Results:

https://doi.org/10.3390/ani12152002

Funding: Aarhus University, DK, 4.451 EUR

Project Details:
On behalf of Aarhus University (Denmark), data on abundance and distribution of marine mammals have been collected annually since 2012. Five Natura 2000 sites in the Danish North Sea and Skagerrak were surveyed in 2021. The main target species was the harbour porpoise (Phocoena phocoena). The flight surveys were conducted by Aarhus University and followed the line transect survey method. ITAW was commissioned to quality assure and evaluate the data collected.

Results:

For the individual study areas, densities and abundances of harbour porpoises could be estimated and the inaccuracies (95% confidence intervals and coefficient of variation (CV)) associated with the estimation were determined. The processed data and results were submitted to the client.

Funding: Bundesamt für Gewässerkunde, Koblenz, 29.583 EUR

Project Details:
Dietary analysis of otters found dead are the subject of this study. Relevant otters where dissected as part of a previous project that aimed at investigating anticoagulant rodenticides (rat poison) in predators. During necropsies, all stomachs and the intestinal content of otters was sampled, if available. Continuing, all remains found in the gastrointestinal tracts of the otters were specially prepared to allow identification of prey species. Two methods will be used therein: hard part analysis, which targets visible bones, scales etc., and metabarcoding, which identifies prey species genetically. In combination, both methods together will create a realistic overview of the prey spectrum of otters from Lower Saxony. All results will be presented as a short report.

Results:

The results of the hard component analysis confirm fish as the most frequently eaten prey class of otters in Lower Saxony. Furthermore, components of amphibians, plants, arthropods, and very sporadically of birds, mammals and molluscs were detected in the stomachs. The Cyprinidae family was the most frequently identified fish family. That otters are opportunistic predators that feed on a variety of fish species depending on availability in their range (Kruuk, 2006; Buglione et al., 2020) was confirmed by the metabarcoding results. The study was able to show that the combination of hard component analysis and metabarcoding is suitable to break down and describe the feeding ecology of otters in Lower Saxony. While metabarcoding could identify fish species that would otherwise have been overlooked, hard component analysis could provide estimates of the number of prey eaten.