When a Wildfire Raged Outside L.A., These Biologists Went on a Rescue Mission—for a Fish
After surviving last summer’s Sand Fire, endangered sticklebacks are getting cozy in their new forest.
The Copper Fire ripped through the San Francisquito Canyon north of Los Angeles in 2002, burning through 23,400 acres. The fire blazed for about a week, but its impact on local aquatic ecosystems was permanent. Wildfires are obviously dangerous to wildlife, but the unarmored threespine stickleback—an endangered two-inch fish that lives in San Francisquito Creek—were in a particularly tight spot.
The Copper Fire’s flames didn’t harm the fish, but the ash and debris it created eventually washed into the creek with the rain. Surveys confirmed that “tremendous amounts of debris and sediment” gagged up the waterway. As years passed, more and more sediment washed into the stream bed. By 2006, a few sticklebacks were still in there making a go of it in the muck, but when scientists returned the following year, the fish were gone. No one has seen a stickleback in the San Francisquito Creek since.
A few centuries ago, you could find unarmored threespine sticklebacks in large stretches of the Los Angeles, San Gabriel, and Santa Ana Rivers, and the fish were abundant throughout the Los Angeles Basin as recently as 1917. But only eight disconnected populations now remain in the area. Worldwide, various subspecies inhabit every continent except Australia and Antarctica, but not all of them have fared well with the relatively recent expansion of humankind. Such has been the case with California’s sticklebacks. Urban development, rerouted water flows, pollution, and the introduction of exotic predators, such as bullfrogs, bass, and crayfish, have significantly shrunk the fish’s habitat.
Fast-forward about a decade to July 2016, when Los Angeles faced an even bigger blaze, the Sand Fire. Over the course of almost two weeks, the wildfire scorched some 41,000 acres, leading county officials to declare a state of emergency and evacuate 10,000 homes. This time, the sticklebacks of Soledad Canyon were stuck.
With the sting of the lost San Francisquito population still in memory, state and federal wildlife agencies decided to try a rescue operation to save at least some of the sticklebacks in the Sand Fire’s path.
“We realized that if we had some substantial rains that following winter, we could lose the stickleback population in Soledad Canyon,” says Chris Dellith, a senior biologist with the U.S. Fish and Wildlife Service.
So, did the scientists risk life and limb, jumping out of helicopters wearing gas masks and carrying axes? Nah. The fish were in an area that hadn’t burned yet, so the biologists just walked in and scooped up 151 of them with dip nets.
The plan for last summer’s stickleback refugees was to keep the fish at the Fillmore Trout Hatchery over the winter and return them to Soledad Canyon whenever its water quality was given the all clear. But when they returned to the canyon to do some tests in the spring, Dellith and his colleagues at the California Department of Fish and Wildlife and the U.S. Forestry Service found that there wasn’t actually any water to test—what was once a free-flowing stream was now a solid plume of ash and sediment. “You’d expect some kind of surface flow,” says Dellith, but “what was left had the consistency of saturated sand.”
Good thing they had a backup plan. An assessment of whether creeks in nearby Angeles National Forest might be hospitable for stickleback restorations was already underway, says Eric Morrissette, another senior biologist with the Fish and Wildlife Service. Repeated visits to Soledad Canyon showed no signs of improvement (even after the Forest Service bulldozed part of the creek in hopes of saving a population of threatened red-legged frogs). So the sticklebacks were headed to a new home in the Angeles forest.
Morrissette, Dellith, and their team released the 151 fish in April, and while it’s still too early to celebrate, the biologists have noted a few promising signs. For starters, no sticklebacks died in the collection, overwintering, or release. That’s pretty awesome, considering we’re talking about a little pipsqueak of a fish. And within just a few minutes of swimming around their new home, the scientists observed the sticklebacks attempting to nibble on some native insects, evidence that they were ready to get back to hunting. The scientists even saw some nesting behavior on one visit and discovered a few larvae on the next.
They hope to perform more of these restorations in the future. That way, Morrissette says, there won’t have to be a rescue every time a fire breaks out in the hills above Los Angeles. (Good thing, considering that catching fire is something Southern California does often.)
And the effort may be worthwhile for reasons other than the inherent value of preventing an extinction. Note the “unarmored” portion of the fish’s full name. Sticklebacks appear to gain and lose scales in response to the amount of predators in their habitat. The fish from L.A.’s canyons are scale-less because they haven’t had to deal with many toothy mouths, whereas sticklebacks in coastal or marine areas—where the aquatic neighbors are a little more dangerous—don a full suit of scale armor. Other populations sport partial scales for a sort of Goldilocks, in-between look. What’s remarkable is that sticklebacks can shift between one morph and another in relatively rapid time, evolutionarily speaking.
“Whatever’s going on at that molecular or genetic level could be a benefit to humankind,” says Dellith. Scientists don’t yet know exactly what that benefit might be, but they definitely don’t want to lose the chance to solve that mystery the next time Los Angeles starts to smoke.
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