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Determining spatial and temporal scales for management: lessons from whaling
Author(s) -
Clapham Phillip J.,
Aguilar Alex,
Hatch Leila T.
Publication year - 2008
Publication title -
marine mammal science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.723
H-Index - 78
eISSN - 1748-7692
pISSN - 0824-0469
DOI - 10.1111/j.1748-7692.2007.00175.x
Subject(s) - whaling , population , minimum viable population , geography , ecology , spatial ecology , habitat , fishery , biology , endangered species , demography , sociology
Selection of the appropriate management unit is critical to the conservation of animal populations. Defining such units depends upon knowledge of population structure and upon the timescale being considered. Here, we examine the trajectory of eleven subpopulations of five species of baleen whales to investigate temporal and spatial scales in management. These subpopulations were all extirpated by commercial whaling, and no recovery or repopulation has occurred since. In these cases, time elapsed since commercial extinction ranges from four decades to almost four centuries. We propose that these subpopulations did not recover either because cultural memory of the habitat has been lost, because widespread whaling among adjacent stocks eliminated these as sources for repopulation, and/or because segregation following exploitation produced the abandonment of certain areas. Spatial scales associated with the extirpated subpopulations are frcequently smaller than those typically employed in management. Overall, the evidence indicates that: (1) the time frame for management should be at most decadal in scope ( i.e. , <100 yr) and based on both genetic and nongenetic evidence of population substructure, and (2) at least some stocks should be defined on a smaller spatial scale than they currently are.