Christian Lydersen

Senior research scientist, marine biology
Christian Lydersen
+47 77750523
Tromsø
Norwegian Polar Institute
Publications
Projects

Current activities

  • Foraging ecology of bearded seals

During the next 3 years, we will perform a series of investigations to explore the dynamics of bearded seal foraging and the effects of these activities on benthic communities of the Arctic. We will:

  1. Complete data collection from captive bearded seal experiments in one final set of trials that includes pressure measurements (and also finish analysing and writing up the previously commenced anatomical investigations of whisker morphology and anatomy, and biokinematic studies with the captive animals);
  2. Deploy cameras on bearded seals in Kongsfjorden to document their foraging activities and its physical impacts on the substrate in the wild;
  3. Explore the relationship between the animals actual behaviour and assessments of behaviour based on dive profiles alone;
  4. Explore diet via isotope analyses of various tissues, and fatty acid profiles in bearded seals compared to potential prey and
  5. Directly explore benthic community assemblages at, near and outside bearded seal foraging areas in order to assess the impacts of bearded seal feeding on the benthic communities composition and productivity in the Arctic. In addition we will deploy state-of-the-art satellite tags in order to study the ontogeny of diving and add to our pup growth and pup-production estimates.

This work is being conducted by an international team of researchers including Drs. Kit M. Kovacs and Christian Lydersen of the Norwegian Polar Institute in Tromsø, Dr. Chris Marshall of Texas A & M University in Galveston Texas, Dr. Mark Hindell of the University of Tasmania, Hobart Australia and Dr. Mike Fedak of the Sea Mammal Research Unit, St Andrews University, St Andrews, Scotland.

  • Population biology of ringed seals (Phoca hispida) in Svalbard, Norway

The principal objective of this research programme is to provide data that will permit the assessment of population and ecological trends for ringed seals on Svalbard. The programme will also provide novel ecological knowledge about this species and essential management information for local, national and international authorities. Sub-goals of the programme include the study of

  • local population structure
  • haul-out behaviour
  • prey availability and territory size
  • density and abundance
  • population parameters 1980’s versus the present
  • seasonal diet
  • "health status" and condition
  • contaminant exposure and effects
  • and training and education of young researchers.
  • Climate impacts on the population ecology of ringed seals and polar bears at Svalbard

Climate change scenarios predict that Arctic regions will experience the most profound changes anywhere on the globe due to global warming in the coming decades. This is of great concern from a conservation and biodiversity perspective because this biome is dominated by specialists that have through evolutionary time adapted to extreme conditions, including cold temperatures and long winters – specialists that are found nowhere else on earth. Polar bears (Ursus maritimus) and ringed seals (Phoca hispida) are two such species. Both are long-lived, sea-ice-dependent, circumpolar high Arctic marine mammals. Foraging and reproductive success of these animals is directly affected by the dynamics of sea ice – which is a climate driven system. Ringed seals are the most abundant Arctic seal and are a keystone species in the Arctic marine ecosystem. Polar bears are the apex predator in this system. Both of these high trophic level animals are ideal indicators of climate- (or anthropogenic-) induced change in the Arctic system. This research programme will explore the impact of climate variability on the movement patterns, growth patterns and interactions of these two species, identify critical habitat features and develop a predictive model to assess the impact of future climate change on these animals and the ecosystem they occupy.

  • Population ecology of walruses on Svalbard
  • Walruses in Svalbard numbered in the hundreds of thousands before 3 centuries of over-harvesting brought the population to the verge of extinction. Today this stock is in an early phase of recovery; it consists of only a few thousand animals. Little is known about habitat utilization, foraging areas or behaviour in this population. This program will use satellite telemetry to identify important feeding areas for walruses. Geographical position data in combination with detailed dive information will provide novel insight into habitat use by this large pinniped. Scat analyses, isotope analyses and surveys of potential benthic prey will provide more specific information about diet. Haul-out behaviour studies, in addition to the satellite data activity budgets will permit the calculation of correction factors for aerial surveys. In addition, we will study the exposure to and effects of pollutants and conduct a general health assessment based on clinical serum chemistry parameters. We will also study the possible endocrine disruption potential of the contaminant mixtures the walruses are exposed to via their diet. Finally, based on information on haul-out behaviour from the satellite telemetry project and observational data, we will conduct a photographic aerial survey to produce a current, accurate population estimate.

Career

  • March 1998: Dr. philos. University of Oslo
  • Aug 1994 onward: Research Scientist, (marine mammals) - Norwegian Polar Institute Jan 1990 -
  • Aug 1994: Research scientist supported by the Norwegian Research Council, Department of General Physiology Institute of Biology, University of Oslo
  • May 1988 - Dec 1989: Research scientist at University of Oslo, Bioenergetics Group, Department of General Physiology, Institute of Biology. Responsible for scientific whaling programme (minke whales)
  • June 1986 - Dec 1987: Research scientist (term) Norwegian Polar Institute
  • March 1984 - May 1986: Contract biologist
  • 1984: MSc - Institute of Marine Biology and Marine Chemistry, University of Oslo
  • 1980: BSc - Faculty of Mathematics and Natural Sciences, University of Oslo

Areas of interest and expertise

  • Marine mammalogy and physiology
  • Population biology
  • Ecology

Supervision of students

  • Aili Labansen, MSc
  • Carina Johansen, MSc
  • Eli Skoglund, MSc
  • Carla Freitas, PhD
  • Bjørn Krafft, PhD

11 MSc students graduated