Endangered Southern California fish saved after population threatened by fire

An unarmored threespine stickleback swims in new habitat after being released into a creek in the Angeles National Forest by a team of biologists and scientists from the U.S. Fish and Wildlife Service and the California Department of Fish and Wildlife. One hundred and fifty-one fish were released following an emergency rescue late last year in response to a fire that threatened their habitat. Credit: Tim Hovey/CDFW

By Robyn Gerstenslager
May 8, 2017


One hundred and fifty-one unarmored threespine sticklebacks (Gasterosteus aculeatus williamsoni) were rescued and then released on the Angeles National Forest this past month.

Nearly a decade ago the U.S. Fish and Wildlife Service, the California Department of Fish and Wildlife, the U.S. Geological Survey, the U.S. Forest Service, and conservation partners came together with the ultimate goal of species recovery, through implementation of the species recovery plan. The plan identifies a goal of reaching sustainable populations, through the creation of additional unarmored threespine stickleback populations, or the reintroduction into new sites.

Chris Dellith (left), a senior biologist with the U.S. Fish and Wildlife Service in Ventura, discusses release plans for unarmored threespine sticklebacks with Tim Hovey, DFW. Credit: Robyn Gerstenslager/USFWS

At the time, one of the team’s first actions was to assess the Santa Clara River watershed for potential suitable habitat for unarmored threespine sticklebacks. This proved critical when in June 2016 the Sand Fire burned more than 41,000 acres adjacent to Soledad Canyon, near Santa Clarita, California, threatening a population of unarmored threespine sticklebacks with ash and sediment flow from impending winter rains. These flows create a toxic environment for the fish.

“Whenever you get something like that, you’re really concerned with ash, sediment and debris that will wash into the creek during even minimal precipitation or rain,” said Tim Hovey, a senior environmental scientist, specialist with CDFW’s South Coast Region Inland Fisheries Program. “So when we saw that, we knew that either we immediately pull those fish out of there, or the next rain we get is going to wash debris and ash down there and threaten to kill them all.”

Collaboration between federal and state wildlife agencies was critical.

“It was a fortuitous opportunity, despite it coming about in response to a crisis,” said Chris Dellith, a senior fish and wildlife biologist with the Service in Ventura, California. “We went and rescued fish knowing, based on prior experiences, that we could lose them all.”

Tim Hovey, with the California Department of Fish and Wildlife, releases unarmored threespine sticklebacks.  “Usually when species are kind of at the door of extinction their adaptation threshold is really low,” said Hovey. Credit: Robyn Gerstenslager/USFWS

Together, the Service and CDFW planned to collect the fish from Soledad Canyon and relocate them to a new site in the Angeles National Forest that was determined to be suitable habitat for unarmored threespine sticklebacks.

“Finding sites like this one in Angeles National Forest that can sustain unarmored threespine sticklebacks are few and far between in the Santa Clara River watershed,” said Eric Morrissette, a senior fish and wildlife biologist with the Service. “We are hopeful that we will be able to find more sites like this to help achieve the recovery goals.”

Tim hovey peers into a container of  unarmored threespine sticklebacks along with biologists and scientists from the Service and California Department of Fish and Wildlife. The team rereleased 151 unarmored threespine sticklebacks into new habitat after conducting an emergency rescue of the fish. Credit: Robyn Gerstenslager/USFWS

But nature had other plans. A week before the planned rescue and relocation operation, the new site had become unsuitable for the fish. Simultaneously, weather forecasts were predicting rain in the area. Despite not having an available site in which to release the fish the team decided an emergency rescue was warranted.

“It was at that point that we determined captivity may be the only choice because there appeared to be no other options,” Morrissette said.

The team collected the unarmored threespine sticklebacks and moved them to CDFW’s Fillmore Fish Hatchery for safe keeping.

However, heavy rainfall in a short amount of time kept the translocation creek unsuitable for release for nearly six months. And, as the team had feared, winter storms caused post-fire debris and ash to fill Soledad Canyon from where the unarmored threespine sticklebacks were rescued; had they not rescued the fish, they probably would have been lost.

Unarmored threespine sticklebacks at the California Department of Fish and Wildlife's Fillmore Fish Hatchery. A team of biologists and scientists from the Service and CDFW moved a small population of the fish to the hatchery late last year. Credit: Robyn Gerstenslager/USFWS

Early one sunny, yet chilly, Southern California spring morning the team of biologists and scientists released the tiny unarmored threespine sticklebacks back into the wild, and the fish immediately began to feed and explore their new habitat.

“We were relieved that the rescue worked, and we were able to get them back in the wild. It was great to see how well they responded soon after we put them in the site,” said Morrissette. “We are encouraged that this reintroduction is part of the larger recovery of unarmored threespine sticklebacks that we are trying to work toward for the whole watershed.”

Unique, endangered subspecies

Chris Dellith, (left)  watches as John O'Brien, a senior environmental scientist with CDFW, tests water quality for its viability to support unarmored threespine sticklebacks. Credit: Robyn Gerstenslager/USFWS

Unarmored threespine sticklebacks, which are native to Southern California, are federally listed under the Endangered Species Act and are listed as endangered and fully protected by the State of California. They are a unique freshwater subspecies of threespine sticklebacks, which are typically common in marine environments.

“This particular subspecies has developed traits that allow it to morph and change its plates from partially armored to unarmored,” said Dellith. “We have so much yet to learn about this remarkable animal.”

Unarmored threespine sticklebacks remain endangered due to loss of suitable habitat. The fish do best in small clean pools in streams with constant water flow through the pool. Drought, coupled with water reallocation has steadily diminished suitable habitat for the fish, which is only two to three inches in length and breeds frequently. As an annual species the majority typically live for about one year.

Hope for the subspecies

The team has begun to monitor the fish and their new habitat, in the hopes that they will soon begin to breed and move toward creating a self-sustaining population of unarmored threespine sticklebacks.

“Usually when species are kind of at the door of extinction their adaptation threshold is really low,” said Hovey. “In other words they can’t adapt to the changing conditions environmentally, and changing habitat. So I look at the stickleback as one of those species. It’s losing habitat, it needs water - and water now in Southern California is like gold.

a small fish in a tank

An unarmored threespine stickleback at the CDFW Fillmore Fish Hatchery. “This particular subspecies has developed traits that allow it to morph and change its plates from partially armored to unarmored,” said Service biologist Chris Dellith. “We have so much yet to learn about this remarkable animal.” Credit: Robyn Gerstenslager/USFWS

“If we can start understanding that and finding new areas where they can live and restoring habitat there’s probably hope for them, but it’s all going to come down to places to put them…and in Southern California those places are definitely numbered,” he said.

 

Robyn Gerstenslager is a public affairs specialist in the Ventura Fish and Wildlife Office. Biologists and natural resource professionals in the Ventura office work with partner organizations along the central and Southern California coast from Santa Cruz County to northern Los Angeles County to conserve, protect, and enhance fish, wildlife, plants, and their habitats.