The Caspian seal (Pusa caspica), which is endemic to the Caspian Sea, is listed as 'endangered' by IUCN due to a severe population decline and a number of unresolved threats. The results of aerial surveys of the Caspian seal population on their breeding ice habitat 2005-2012 are outlined in the Chapter 2. They demonstrated extreme fluctuations in pup production estimates between consecutive years which might be result of sampling error or underlying biological drivers influencing the fecundity of the population. The results of satellite tracking of Caspian seals in 2008-2012 are presented in the Chapters 3 and 4 including analysis of movements and habitat use respectively. In Chapter 3 the true path of seals was predicted by state-space modelling (SSM) and two behavioural states were distinguished from the locations: 'travelling' and 'foraging'. Chapter 4 used SSM results to identify important foraging areas and seasonal patterns of habitat usage. The results revealed high individual variation in habitat use which suggested individual foraging specialization in Caspian seal. The North Caspian is suggested to be a highly important habitat area for the Caspian seals throughout the year, where seals breed, moult, forage during their migrations and large proportion of seals (40% in our sample) stay for the whole all ice-free period. Chapter 5 presented first quantitative assessment of fisheries by-catch mortality of Caspian seals by interviews in fishing communities along the coasts of Russia (Kalmykia, Dagestan), Kazakhstan and Turkmenistan and revealed high by-catch rates related with sturgeon poaching. High by-catch mortality rates and overlap between critical habitat areas used by seals and human activities revealed by the study should cause concern for stakeholders. These results of the thesis can be used for developing and implementing effective conservation strategies for Caspian seals.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:634441 |
| Date | January 2013 |
| Creators | Dmitrieva, Lilia |
| Publisher | University of Leeds |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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