Pesky Red Swamp Crayfish

Jul 28, 2014

Malibu Creek–tracie7779 FlickrThere are a lot of acronyms involved in this story, like MRT, OBA, and NPS. These are the “big dogs” behind 5 Pasadena students, and many other volunteers, who have been making their way to Malibu in order to restore a balanced environment.

It seems Malibu Creek has been overrun with non-native crayfish, specifically the Red Swamp crayfish, and they  need to be evicted.

The Mountain Restoration Trust (MRT) works with government agencies to “maintain a cooperative relationship between urbanization and native land,” and, needless to say, the Red Swamp boys are not cooperating. Charles H. Thomas, National Park Service (NPS) Youth Programs manager and former executive director of Outward Bound Adventures (OBA), which has been based in Pasadena for the last 52 years, has coordinated a project to eliminate the “invasive” Red Swamp crayfish.

The goal: “100% eradication.”


The project is being funded by the California Department of Fish and Wildlife (CDFW) and is “the first project of its kind in attempting to clean an entire watershed of crayfish.”

In the early 1900s, these crayfish were introduced into Malibu Creek. They were used as bait for sport fishing and also released into the water. But they “cause problems with riverine biome and reduce biodiversity,” which can lead to ecosystem and food web problems. And besides, they’re “a pest.”



Actually, the Resource Conservation District of the Santa Monica Mountains is more blunt: “The red swamp crayfish (Procambarus clarki) is a predator and scavenger with potentially devastating impacts on native amphibian, fish, and invertebrate populations.” (

Removal will be done with minnow traps, which will have a “low impact on native reptiles and amphibians,” setting up barriers every 100-150 yards to ensure that the crayfish don’t migrate to other parts of the stream, and for the stragglers, seine nets will be used.


The captured critters will be “humanely euthanized by freezing,” then given to CDFW-approved wildlife centers to use for feeding injured and recovering animals.

Two sets of four people will be, on a daily basis, checking traps, performing seine net sweeps, and keeping the temporary barriers in good working order.

What they hope to achieve in two months time is:

  • 1200 yards of crayfish-free creek
  • A greater population of macroinvertebrates & healthy indicator species
  • Less erosion
  • A return of native plants
  • An increase of biodiversity


What they hope the Pasadena students will achieve:

  • Teamwork skills
  • Appreciation of the outdoors
  • Development of life skills, which are applicable to all walks of life & employments
  • Development of a scientific mind, meaning critical and inquisitive thinking

Oh, yes, and how to enjoy getting muddy!

According to the MST website, over 40,000 Red Swamp crayfish have been removed from the creek.

Students normally volunteer Thursday, Friday, and Saturday, 9:30-11 a.m.

Charles Thomas kindly shared some important additional information:
OBA is providing the crew leader and transportation but the City of Pasadena Summer Rose program is paying the salary for the youth in the program.  The program is unique in that National Park Service and the City of Pasadena have created a Careers in Conservation Program that is directed at engaging youth, (especially urban youth of color) in outdoor careers, where that demographic is all but absent. 

Want more information? Visit

Source reference: “Non-Native Crayfish Removal from Malibu Creek Watershed,” Mountains Restoration Trust 2014.


Photo of Malibu Creek State Park, top right, by tracie7779 at Flickr/Creative Commons




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