Study: Harbor Seals Consume up to a Third of Steelhead Migrating out of Nisqually River Delta
Unchecked predation may undermine recovery actions, researchers find.
Harbor seals consume as many as a third of young steelhead smolts migrating out of the Nisqually River’s delta in southern Puget Sound, new research shows.
The finding indicates that recovering populations of predators can derail salmon and steelhead recovery, especially when fish populations are small and struggling.
Scientists said the results, published in the journal Marine Ecology Progress Series, demonstrate the need to test new management actions to exclude seals from areas where salmon are most vulnerable. Although seals are protected by the Marine Mammal Protection Act, some steps may help limit their impacts.
“If we can identify areas with outsized predator impacts on salmon such as river deltas, managers...