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Preface:

This report summarises the available knowledge
on odontocete (toothed whale) distribution, behaviour, migration and threats and was compiled for the Bonn Secretariat of CMS.
First of all, how is the term “migration” to be interpreted?
According to the Bonn Convention on the Conservation of Migratory Species of Wild Animals, “Migratory species” means the entire population or any geographically separate part of the population of any species or lower taxon of wild animals, a significant
proportion of whose members cyclically and predictably cross one or more national jurisdictional boundaries".

What methods were employed to compile this review? While I compiled published information, I sent several emails via the marine mammal science (MARMAM) and the European Cetacean Society (ECS) list servers in order to obtain the latest information from the specialists in the field. The information returned, for which I am very grateful, is cited as (pers. comm.) in the report where appropriate. With respect to scientific
papers, I used the Aquatic Science and Fisheries Abstract (ASFA Silver Platter) from 1978–2003 as well as the Biological Abstracts Service from 1990–2003 available at the library of the Institut für Meereskunde, Kiel. Both services monitor a very wide variety of biological,
aquatic and marine scientific literature and are very good sources of full abstracts of scientific papers. To select relevant publications, I used the coarsest possible filter, i.e. the species name, and then selected
“by hand” as well as via the Reference Manager software the appropriate sources from the wide variety of information presented. Where possible, I obtained the original papers in order to incorporate firsthand information in this report. Moreover, this review summarises
information spread over a variety of media, i.e. books, scientific papers, conference abstracts and the internet. All sources are quoted individually for each species or genus. This paper is intended to summarise available information
on migratory patterns of odontocetes on a species and population level. However, in many cases we still know too little to subdivide odontocete species into reproductively isolated populations. Rice (1998) stated that: “Initial faith in the near-infallibility of molecular studies has now been tempered by a more sober appraisal
of their strengths and weaknesses. Molecular techniques are not free of many of the difficulties that beset morphological techniques, and they have some of their own… Perhaps the most serious deficiency that has compromised the credibility of many molecular
phylogenetic studies is that each higher taxon is usually represented by only one or a few of its species. Another serious deficiency has been the routine use of only one or at most few specimens to represent each species, so that no cognisance is taken of individual or geographic variation. For example, in a cladogram based on the amino acid sequences of myoglobin, one specimen of Delphinus delphis formed a clade with Tursiops truncatus and Stenella frontalis, but another specimen formed a clade with Globicephala melas and Orcinus orca.” (Rice 1998) With respect to migratory behaviour, another word of caution came from Robin Baird (pers. comm.): “I know that for most species of cetaceans the information available on possible migratory patterns is pretty sparse,
and what is available is often fraught with sampling
biases. I’m amazed how often people conclude animals migrate because they don’t see them during the winter (when the days are short, the amount of survey effort is minimal etc.).” Finally, I would -point out that the range states mentioned under the heading
“Remarks” are not necessarily countries where the species has been directly sighted (these are found under “Distribution”) but those states touched by the distribution of the species as shown on the maps. With these limitations in mind, I hope that the reader will find this “snapshot”-review of available information useful, be it as a basis for future conservation efforts, or to outline the necessity for further research.
I would like to thank W.F. Perrin, La Jolla, California for proof-reading the first version of the MS, for his constructive and helpful criticism, and for sharing with me the most recent IWC literature. Special thanks go also to R.Strempel of ASCOBANS, Bonn, Germany, for proof-reading this final version and his many helpful comments.
Kiel, December 2004 Boris Culik