Where sea otters play, salt marshes stay, new study shows

[Judi Lynn]

by Elizabeth Claire Alberts on 7 February 2024

A new study has found that sea otters are helping to slow down salt marsh erosion in Elkhorn Slough in California by eating burrowing crabs.

Drawing on a range of data sources, which included surveys and field experiments, the authors found that in places where sea otters were abundant, the erosion of the salt marsh slowed by as much as 80-90% over the course of the study.

Salt marshes worldwide are disappearing due to climate change-driven factors such as rising sea levels and other human pressures.

Sea otters are slowing down the erosion of salt marshes, thanks to their rapacious appetite for crabs, according to new research.

But it took some sleuthing to figure this out.

Marine ecologist Brent Hughes said he and his colleagues first noticed sea otters (Enhydra lutris) using the tidal creeks and salt marshes of Elkhorn Slough estuary, near Monterey, California, about a decade ago. This got them thinking about the relationship between the otters and the coastal wetlands they inhabited — or rather, reinhabited. Otters used to be abundant in many estuaries along the West Coast of the United States but were virtually wiped out by fur traders in the 19th century. But now, the otters are back.

“This presented a really unique opportunity to study the effects of a recovering top predator on a salt marsh ecosystem that was under a lot of [stress due to] anthropogenic effects and negative effects,” Hughes told Mongabay.

Salt marshes are estuarine habitats that thrive on the ebb and flow of tides. These coastal wetlands provide a myriad of ecosystem services. For instance, they act as giant filters, trapping pollutants such as pesticides, herbicides and heavy metals that would otherwise wash out to sea. They also provide critical habitat for fish and other species, help stabilize shorelines, and even store carbon. Yet, in many parts of the world, salt marshes are disappearing due to rising sea levels — a result of human-induced climate change — which leads to the erosion of these coastal habitats. They’re also threatened by other human-led factors, such as coastal development, aquaculture, pollution, and an influx of invasive species.



More:
https://news.mongabay.com/2024/02/where-sea-otters-play-salt-marshes-stay-new-study-shows/



(On edit, I think the thing lying across otter's nose is a strip of seaweed! It does look as if someone tried to put a muzzle on it. They love seaweeds. )

This otter has wrapped itself in kelp.









For afternoon snacks, an urchin assortment.