Partitioning the Lifecycle: Domains

Defining the spaces and times in the salmon lifecycle to focus attention on understanding mortality processes

Consideration of the range of space-time domains occupied by salmon as they transition across life stages and change habitats is important when discussing the range of changing conditions, possible pressures, and the potential drivers of the survival patterns we see in populations through time. The conditions and factors influencing salmon in these series of domains will vary and may result in a direct response (e.g. death or poor growth). They may be expressed cumulatively with responses in a subsequent domain or act together in more complex (synergistic) ways on salmon survival chances.

Challenges undoubtedly remain when proposing the spatial and temporal limits for many of the marine phase domains, as those representing migration routes will vary in location and duration by salmon stock, whilst a different pattern of use may be represented by stocks sharing the main feeding ground domains in the Norwegian and West Greenland Seas. Thankfully, science is rapidly advancing our understanding of salmon marine phase domains and is increasing the opportunities to extend our reach out from freshwater–based science and start to link up valuable data resources that could help uncover the processes driving changes in marine survival.

The MSA Likely Suspects Framework Team are currently involved in maximising the opportunity for researchers to gain access to existing knowledge resources to facilitate the development of a clearer picture of marine survival process in Atlantic salmon. These efforts are directed initially by a thirst to address key mortality questions (i.e. test specific hypotheses) and focus efforts on associated salmon domains.

There are five focal domain categories associated with the subset of eleven initial priority mortality hypotheses. These categories can be used to search available knowledge resources, structure queries and assess the extent of available resources to advance with testing hypotheses.