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Joint Effort to Monitor the Strait of Juan de Fuca

JEMS (Joint Effort to Monitor the Strait of Juan de Fuca) was established in 1999 out of a critical need to understand how oceanic conditions entering Puget Sound via the Strait were influencing inland water quality. The monthly cruises conducted out of UW-FHL on the R/V Centennial are crucial in establishing the boundary conditions for running the Puget Sound models. The JEMS data are also essential for interpreting Puget Sound’s water quality, since oceanic conditions are not static. Inflowing oceanic waters can sometimes have qualities e.g., low oxygen concentrations, that can complicate interpretation of water quality within the Sound.

The data from the JEMS cruises are available at

No data were available for these purposes prior to JEMS. The “Joint Effort” part of JEMS is a testament to strong regional partnership that formed in response to need. PRISM was a founding, and now sustaining, sponsor of JEMS. Currently the Washington Department of Ecology is the primary sponsor of JEMS. The cruises are run out of UW-FHL on the R/V Centennial, another sustaining sponsor.  Former sustaining sponsors of JEMS are the Marine Ecosystem Health Program (now Sea-Doc Society), King County Department of Natural Resources, Puget Sound Action Team (now Puget Sound Partnership), the Washington Department of Health, and NOAA.