Kelp health is crucial to the health of the marine ecosystem, providing a foundation for forage fish, salmon, crabs and even whales.
A recent study by the state Department of Natural Resources discovered that South Puget Sound shorelines have lost two-thirds of their bull kelp forests since 1870.
There are 22 species of kelp in the state, but it’s bull kelp that most folks encounter on the water.
Using topographic maps from the 1870s to draft a baseline, scientists with DNR, Marine Agronomics and the U.S. Geological Survey found a 63 percent decline in kelp forests dating back to the baseline, and 80 percent compared with its maximum extent over 145 years.
Losing kelp forest habitat could be one of a long list of reasons for declines in crab and salmon populations in South Puget Sound.
A similar 2018 study of the Strait of Juan de Fuca and a portion of the Pacific coast was researched by Natural Resources’ Helen Berry along with Cathy Pfister of the University of Chicago and Tom Mumford of Marine Agronomics and published in the Journal Ecology.
The study found kelp forests have remained stable with the most abundant and persistent growth along the Strait of Juan de Fuca and the Pacific Coast from Cape Flattery to Destruction Island when compared with historical surveys conducted in 1911-12.
Meanwhile, kelp forests declined in the eastern Strait over that same time. The proximity of kelp forests to human population centers and their distance from cooler ocean waters likely accounts for the decrease.
Along the Strait and Pacific Coast, researchers discovered increased kelp cover occurred in conditions where seawater is colder and more nitrogen rich.
In Puget Sound, bull kelp growth has been found along shorelines with intense currents and mixing, where temperature and nutrient concentrations didn’t impact growth and high currents limited grazing. An example is the Tacoma Narrows area.
The greatest losses of kelp were found in areas with elevated temperature, lower nutrient concentrations and relatively low currents.
For more information, visit tinyurl.com/PDN-StraitKelp.
New boating law
The Coast Guard is advising operators of recreational vessels less than 26 feet in length of a new law taking effect April 1, requiring the use of an engine cut-off switch and associated link.
The engine cutoff switch and link prevent runaway vessels and the threats they pose.
The link, usually a lanyard-like cord that attaches to the switch near the helm or on the outboard motor if the vessel is tiller operated, attaches the vessel operator to a switch that shuts off the engine if the operator is displaced from the helm.
When enough tension is applied, the ECOSL disengages from the ECOS and the motor is automatically shut down.
Wireless ECOS have recently been developed and are also approved for use. These devices use an electronic fob that is carried by the operator and senses when it is submerged in water, activating the ECOS and turning the engine off. These can be purchased from retailers, and some boats are beginning to have them installed.
Fee-free day
Today is the third of 12 State Parks free days in 2021, when visitors are not required to display the Discover Pass for day-use visits to a park.
The free days apply only at state parks; the Discover Pass is still required on Fish and Wildlife and Natural Resource lands.
Upcoming free days in state parks include a spring free day on April 3 and Earth Day on April 22.
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Sports reporter Michael Carman can be contacted at 360-406-0674 or mcarman@peninsuladailynews.com.
