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Water circulation in Puget Sound is important for flushing out nutrients and affects dissolved oxygen. This overview describes Puget Sound's two-layer circulation process where fresher surface water flows out to sea while saltier ocean water flows in along the bottom. Dissolved oxygen in Puget Sound basins varies by location and season, and is

This overview describes how nitrogen in the marine environment changes depending on oxygen levels and can be lost from the system as nitrogen gas. In spring and summer, nitrogen near the surface of the Salish Sea may become low enough to limit primary production, and organic carbon that settles into sediments can reduce dissolved oxygen.

A state plan calls for reductions in nutrients across 163 distinct watersheds in Puget Sound, including non-point-source pollution. Agencies and restoration practitioners are looking at ways to measure the problem and hope to work with a broad slew of landowners and other partners to help control it. This article is part of an occasional series on

Short-finned pilot whales occur around the world as distinct populations, but records of their occurrence in the Salish Sea are rare. Pilot whales are highly social, with some of the strongest bonds known among cetaceans. Unfortunately this makes them vulnerable to mass strandings and hunting.

The 15th annual Puget Sound Marine Waters Overview combines summaries of monitoring data for marine conditions occurring in 2025. It represents the collective work of federal, tribal, state, and local agencies, academia, nonprofits, and private and volunteer groups.

Described as ‘ocean nomads,’ sperm whales range widely throughout the world’s oceans. In Puget Sound and the Salish Sea, there has been only one documented record of a sighting in Haro Strait in 2018.