Sebastien Lemieux

McGill University
Ph.D. candidate

Supervisor: Murray Humphries
Véronique Lesage, DFO
Start: 2009-09-01
End: 2019-01-01


Integrating distribution and behaviour to identify critical habitats: a case study focused on St Lawrence beluga whales
In recent decades, the identification of critical habitats has been central to major conservation laws protecting endangered species in North America. The focus on critical habitats of endangered species follows evidences that habitat loss, fragmentation and degradation are the main drivers of modern species extinction, range contraction and decreased abundance. Identifying and conserving critical habitats is thus considered an essential step in minimising the effects of habitat loss on endangered species. However, approaches used to identify critical habitats vary greatly across different species, ecosystems and designation context. There is hence a necessity to develop specific approaches for the effective identification of critical habitats of endangered species. The St Lawrence population of beluga whales (Delphinapterus leucas) is classified as threatened under the Canadian Species At Risk Act and non-recovering despite over 30 years of protection. Reasons for this situation are unclear, but may include several factors related to the quality of available habitats. This underlines the urgent need to define and protect the critical habitat of this endangered population. My general research objectives are thus to: Review the different approaches used to identify critical habitats of Canadian species at risk and relate those to their general ecology in order to identify which factors influence the critical habitat identification process. This review will allow me to examine the advantages and disadvantages, as well as opportunities and constraints, associated with the different approaches and/or species considered. Use data on St. Lawrence belugas collected during the past 25 years through individual remote tracking and herd visual survey to establish the functions, characteristics and critical nature of preferred habitats over an extensive spatial coverage. This research will follow the general approach of habitat selection studies, but will also integrate behavioural and habitat information to assess how belugas behave in different habitats, what habitat differences may lead to habitat-specific behaviour, and how these factors can reveal the critical habitat of St. Lawrence belugas.


Critical Habitat, St. Lawrence Beluga Whale, Habitats essentiels, Béluga, Estuaire du St-Laurent, Ecologie comportementale/Behavioural ecology