[MARMAM] Age determination workshop announcement

F.L. Read f.read at erasmusmc.nl
Tue Feb 14 04:56:24 PST 2006

Dear Marmamers,

Workshop announcement for age determination in marine mammals at this
years ECS conference.


Fiona Read


Age determination in marine mammals: with special reference to
techniques employed, interpretation of GLGs and anomalies, using both
tooth sections and digital photos. 

Saturday 1st April 2005, 8:30 - 17.00 

The workshop will be held immediately prior to the 20th European
Cetacean Society in Gdynia, Poland at the Institute of Oceanography,
University of Gdansk (Pilsudskiego 46) - only 15 min. walk away from the
conference venue. Equipment available will include stereo microscopes
(magnification x 10-50) and a laptop and a beamer/projector. 

Organisers: Fiona Read1, Patricia Lastra2 and Christina Lockyer3 
(1) Department of Virology, Erasmus Medical Centre, Rotterdam, The
Netherlands (f.read at erasmusmc.nl ) 
(2) Department of Zoology, University of Aberdeen, Aberdeen, U.K.
(p.lastra at abdn.ac.uk ) 
(3) Age Dynamics, Kongens Lyngby, Denmark (agedynamics at mail.dk ) 

Max. attendance: 20 

Registration: The workshop is aimed at people already working on
materials for determining age parameters and the number of participants
is limited to 20 people. Registration will cost 10 euros per person,
excluding lunch and pre-registration is essential. To register please
contact Fiona Read (f.read at erasmusmc.nl). 

For those who are interested in bringing their own material (either
teeth preparations or digital images), we would be deeply grateful
whether you could let us know as soon as possible. 

Background and objectives: 

The estimation of age is important for the interpretation of many
aspects of the biology, ecology and physiology of marine mammals and to
provide information on population structure to underpin conservation and
management measures. 

Interpretation of incremental and depositional structures (tooth dentine
and cement, tympanic bulla, jaw bones, baleen plates, ear-plug, etc.,)
is routinely used to estimate age in long-lived species such as marine
mammals. Pinnipeds and Odontocetes are readily aged by counting
incremental growth lines or Growth Layer Groups (GLGs; sensu Perrin &
Myrick, 1980) present in dentine and/or cementum (Klevezal &
Kleinenberg, 1967; Perrin & Myrick, 1980; Hohn et al., 1989; Lockyer,
1995; Hohn, 2002). 

Different preparation techniques and viewing platforms have been
developed for estimating age in cetaceans and each has advantages and
disadvantages. Nevertheless, the reliability of the technique depends on
methodology, interpretation of GLGs, reader variability and availability
of known-age animals to validate readings. 

Objectives The aim of this workshop is to bring together biologists
working on life histories and population biology of marine mammals to
discuss recent advances in age determination methods. We will review
advantages and disadvantages of different techniques and identify gaps
in knowledge. Finally, we will compile all the information gathered into
a short report on the current status of age determination methods for
marine mammals. 

Main aspects to be covered during the workshop 

1- General background: Importance of age determination in the study of
population biology in marine mammals. 

2- Review of materials and methods (baleen, teeth, ear bones, eye lens,
aspartic acid racemisation, etc.) and techniques used. Discuss new
techniques / approaches for age determination and problems people have
experienced during their work. 

3- Discuss the term Growth Layer Group (GLG): Group discussion with a
practical session. Split everyone into small groups to analyze prepared
teeth from various species using different methods and then draw
together an interpretation of GLGs. 

Discuss approaches to calibration of age in marine mammals:
   Known-age or known history animals
   Time-marking hard tissues by using tetracycline antibiotic treatments 
   Other biological parameters supporting age: pregnancy records, female
ovulation, etc.

Tooth reading exercises using slides of own preparations. 

Discuss results from the practical session: 
   Use of dentine and / or cementum
   Comparisons of our readings: inter-reader comparison. 

4- Anomalies: Investigate and interpret unusually contrasting layering
patterns present in the tooth ultra-structure (dentine &/or cement) of
marine mammals. 
   a- Slides presentation of different kind of anomalies
   b- Discuss causative factors likely linked to anomalies
   c- Discuss how to deal with such problems
   d- Use of anomalies in distinguishing populations, and life-history

Practical session: Small groups focusing on anomaly interpretation in
different species. Summarized by a short group discussion. 

5- Microscope investigations of prepared tooth sections with age trials
followed by a question and answer session focusing on the slides

6- Summary and conclusions of workshop and future work 


Materials: All participants are encouraged to bring samples to the
workshop, especially from known-age animals, teeth with anomalies,
time-marked specimens, and samples from all types of marine mammals e.g.
cetaceans, pinnipeds, polar bears, otters, etc. NOTE that this will be
easy within the EC countries. If coming from outside the EC, a CITES
permit for export and import may be necessary, and may need to be
initiated a.s.a.p.. To circumvent this issue, we suggest bringing
digital photographs instead wherever possible! 

Hohn, A.A., 2002. Age Determination. Encyclopedia of marine mammals.
Edited by W. F. Perrin, B. Würsig and J. G. M. Thewissen. San Diego,
Academic Press: 6-13. 

Hohn, A.A., Scott, M.D., Wells, R.S., Sweeney, J.C. and Irvine, A.B.
1989. Growth layers in teeth from known-age, free-ranging bottlenose
dolphins. Mar. Mamm. Sci. 5(4): 315-342. 

Klevezal, G.A. and Kleinenberg, S.E. 1967. Age determination of mammals
from annual layers in the teeth and bones. Translated from Russian by
the Israel Program for Scientific Translations, Jerusalem, Israel, 1969:

Lockyer, C. 1995. A review of factors involved in zonation in odontocete
teeth, and an investigation of the likely impact of environmental
factors and major life events on harbour porpoise tooth structure.
Rep.int. Whal.Commn (Special Issue 16) : 511 -529. 

Perrin, W.F. and Myrick Jr, A.C. (Eds) 1980. Age determination of
toothed whales and sirenians.Rep.int.Whal.Commn (Special Issue 3) :

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Fiona Read
Life History of Harbour Seals
Department of Virology
Erasmus MC
P.O. Box 1738
3000 DR Rotterdam
The Netherlands

Tel: +31 (0)10 408 8069
Fax: +31 (0)10 408 9485

E-mail: f.read at erasmusmc.nl

Visiting address:
Dr Molewaterplein 50
3015 GE Rotterdam

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