The following key questions related to factors causing or contributing to the decline
of Steller sea lions are structured as follows: [Specific
type of effect] [Reason for the decline]
[Mechanism].
F1: Have removals of prey
by fisheries reduced ecosystem-wide prey
abundance or availability resulting in decreased
survival or births of sea lions through
nutritional stress?
F2: Have removals of prey
by fisheries reduced local prey abundance or
availability resulting in decreased
survival or births of sea lions through nutritional
stress? (This question also address the
timing of local fisheries during the year (e.g.,
winter) and effects on sea lion prey
availability.)
F3: Have disturbances of
prey by fisheries reduced the density of
individual prey patches and their availability
resulting in decreased survival or birth
of sea lions through nutritional stress?
F4: Have disturbances of
prey by fisheries changed the distribution,
size, or number of prey patches and their
availability resulting in decreased
survival or births of sea lions through nutritional
stress?
F5: Have competitive
spatial disturbances by fisheries changed the
availability of prey resulting in decreased
survival or births of sea lions through nutritional
stress?
F6: Have fishery catches
changed the composition of the fish community
and the abundance, availability, or quality of
prey resulting in decreased survival or
births of sea lions through nutritional
stress?
F7: Have fishery catches
changed the composition of the fish community
causing increased predation (i.e., trophic
cascade) on sea lions resulting in decreased
survival through direct mortality?
F8: Have fishery catches
changed the composition of the fish community
causing increased competition for prey with
sea lions resulting in decreased survival or
births through nutritional stress?
