Menu
Contact Us Search

Science Spotlight

Science Institute News

rss

Recent accomplishments of CDFW's scientific community


Suisun Marsh Study Seeks to Unlock Mysteries of Western Pond Turtles

Suisun Marsh Study Seeks to Unlock Mysteries of Western Pond Turtles

A woman in a marsh holds a turtle
Two men in a marsh, one holds a turtle
Gloved hands hold a pond turtle with long claws
A man throws a trap into a marsh slough
A pond turtle in a marsh pond
Pond turtle's face, close-up
Gloved hands hold a pond turtle as someone neasures its height
Hands hold a six-inch pond turtle with long claws

Does the Western pond turtle (Actinemys marmorata), a freshwater species native to the Pacific Coast, hold secrets to survive climate change and adapt to rising sea levels? CDFW biologists want to know and have partnered with UC Davis and the Department of Water Resources to conduct a long-term study in Solano County’s Suisun Marsh to better understand the aquatic reptiles.

Officially, the Western pond turtle is a Species of Special Concern in California because of declining populations brought about by habitat loss, degradation and competition from that pet store favorite – the non-native, red-eared slider. The pet slider turtles are often released into the environment by their owners after outgrowing or outliving their welcome. They also outgrow and out-compete the medium-sized western pond turtles for food and critical basking spots. Western pond turtle populations are faring even worse in Oregon and Washington.

And yet in the Suisun Marsh, with its brackish water and high salinity, the Western pond turtle appears to be thriving. The Suisun Marsh, ironically, may now be home to one of the strongest populations of Western pond turtles on the West Coast.

“It’s just a really unique population in a place where we didn’t expect to see a freshwater species,” said Mickey Agha, the UC Davis Ph.D. student leading the link opens in new windowuniversity’s turtle research with Dr. Brian Todd, an associate professor in the UC Davis Department of Wildlife, Fish and Conservation Biology.

As if to underscore the point, researchers this summer collected a turtle with a barnacle attached to its shell – a testament to the marine-like environment to which the Suisun Marsh turtles have adapted.

Researchers also have been impressed with the age, health and size of the individual turtles. At 1 ½ to 2 pounds and with an upper shell that stretches up to 8 inches in length, researchers are discovering some of the largest Western pond turtles ever recorded in California.

“Looking at the ones we’ve collected, we’re seeing a lot of healthy turtles in good body condition,” said Environmental Scientist Melissa Riley, who is leading CDFW’s efforts.

The research began in the summer of 2016 with scientists trying to get a basic sense of turtle population numbers. The turtles are trapped in baited, floating hoop nets, their size, weight and age recorded. Before being released, each turtle is marked by filing a unique pattern of small notches along the edges of the upper shell. More than 125 turtles have been recorded in the project’s database.

Turtle trapping is taking place on three sites at the Suisun Marsh in and around the Grizzly Island Wildlife Area. Biologists are particularly interested in turtles at the Hill Slough Wildlife Area along Grizzly Island Road as 500 acres there will soon be restored to tidal marshland. Biologists plan to affix tiny, solar-powered, GPS tracking devices to some of the turtles to study their movements and see how they respond to the increasingly saltwater environment at Hill Slough and other parts of the marsh.

“That’s one of the many questions we have,” Agha said. “If sea level rise occurs, what happens to these turtles?”



Recent Posts

  • CDFW Bands Together with NWTF to Benefit Wild Turkey Hunters Posted 6 days ago
    Tim Hermansen of CDFW carries a turkey holding box to CDFW’s Levi Sousa while John Davis clears the net. Derek Schiewek of CDFW holds a turkey while CDFW’s Laura Cockrell measures the tarsus. Recent efforts to determine the number of turkeys ...
  • Replenishing Southern California’s Abalone Populations Posted 2 weeks ago
    WARC diver Shelby Kawana assesses habitat at one of the CDFW red abalone stocking sites located off the coast of southern California. WARC diver Armand Barilotti assesses habitat at one of the CDFW red abalone stocking sites located off ...
  • CDFW Pilot Study Establishing Foundation for Enhanced Study of Porcupines Posted 3 weeks ago
    Porcupine1: NRVP participants Greg Moore, Mike Maulhardt, Charles Brown and Ben Smith volunteered to service and maintain porcupine stations at Red Lake Wildlife Area. Not to put too fine a point on it, but studying California’s porcupines hasn’t traditionally been ...
  • Sierra Nevada Bighorn: A 21st Century Wildlife Success Story Posted last month
    These pregnant females will bolster the population of a newly established herd as well as provide an infusion of fresh genetic material to helps ensure their new herd’s health and long-term survival. Outfitted with an ear tag and two tracking ...
  • Saving the Burrowing Owls Posted last month
    A dwindling population of a tiny owl in Southern California has a chance at a comeback, thanks to a collaborative effort by scientists from CDFW, the San Diego Zoo’s Institute for Conservation Research (ICR), Caltrans and the U.S. Fish ...
Read More »

CDFW Science Institute logo