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Grey seal predation Schleswig-Holstein; comprehensive advanced investigations regarding grey seal predation on marine mammals in German waters


Project leader: Prof. Prof. h. c. Dr. Ursula Siebert
Scientific work: Dr. Abbo van Neer
Project term: March 2016 through May 2019
Sponsorship: Ministry of Energy, Agriculture, the Environment, Nature and Digitalisation (MELUND)

Project Description 


In this project the findings regarding grey seal predation, which were obtained in an earlier pilot study, shall be applied and extended. Retrospective studies indicate that predation occurs for a longer time and on a larger scale than previously known. However, an uncertainty exists about several aspects, especially the range of this behaviour and the associated impact on marine mammal populations and their ecosystem. Against the background of these findings and the constantly increasing number of grey seals the ecological backgrounds, frequency and potential causes as well as consequences of this behaviour shall be assessed in this study.

Standardised and reproducible methods are required in order to conduct a scientifically verified evaluation and quantification. Therefore, methods for the evaluation of carcasses shall be established in this secondary project to analyse the cause of death of stranded marine mammals and to prevent misinterpretations in the future.

Following questions shall be investigate

  • Since when does this predation behaviour occur against other marine mammals?

If it is a recent behaviour, it is to be determined if and which alterations in the ecosystem caused this phenomenon.

  • Are the concerned grey seals individual animals?

In order to deviate the behaviour´s ecological relevance for the ecosystem, it shall be investigated if it is an anomaly of individual seals or if it is a prevalent and common behaviour.

  • Which age group and sex can these grey seals be allocated?

Existing data shall be analysed if it is a sex- or age-specific behaviour potentially. They shall assist to clarify the behaviour´s possible ethological origin.

  • Are there regional and seasonal foci of these incidents?

The spatial dimension of this behaviour shall be investigated as well as whether there are sensitive periods when this behaviour can be observed potentially. Hence conclusions on possible impacts on other marine mammal populations can be derived.

  • Which behaviour do predating grey seals exhibit?

This aspect is important for the evaluation of carcasses in order to better judge and assess lesion patterns.

  • Which diagnostic tools are available?

Histopathological analytical methods shall be tested and standardised to reliably estimate the carcasses´ cause of death.  

  • How can grey seal predations be distinguished from other kills, for example by terrestrial predators?

For this purpose cost-efficient genetic techniques shall be established, which can be utilised to detect grey seal predation in general.

The findings gained in the framework of this project shall facilitate a management of marine mammals in German waters and beyond, based on substantiated knowledge.



Grey seal induced injuries of a joung harbour seal (Phoca vitulina) © ITAW

Contact person

University of Veterinary Medicine Hannover, Foundation Institute for Terrestrial and Aquatic Wildlife Research Werftstr. 6 25761 Büsum


Abbo van Neer

E-Mail schreiben

Stiftung Tierärztliche Hochschule Hannover
Institute for Terrestrial and Aquatic Wildlife Research
Werftstr. 6
25761 Büsum
Tel.:+49 511 856-8162
Fax.:+49 511 856-8181
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