Trout tallied in Big Chico Creek survey
The first week of August, on the heels of PG&E and the California Department of Fish and Wildlife counting spring-run chinook salmon in Butte Creek, five researchers working with Chico-based FISHBIO were snorkeling in Big Chico Creek tallying trout.
The purpose of the survey, conducted in Chico State’s Big Chico Creek Ecological Reserve (BCCER), was to get an initial count of the creek’s native fish—steelhead and rainbow trout—as well as its population of brown trout, which were introduced a number of years ago. It’s been more than a decade since a fish count of any kind was conducted in the creek. The 4,000-acre BCCER sits off Highway 32, about 10 miles east of Chico and borders Upper Bidwell Park.
FISHBIO, which is located in downtown Chico, did the survey without compensation.
“It’s a way of just giving back to the community,” said founder Doug Demko, who attended Chico State 25 years ago. He said the count is the first step in what he hopes will be an ongoing project to monitor the health of the creek by taking note of fluctuations in fish populations.
“The Butte Creek count is for the spring-run salmon,” Demko said. “They are the focus of all the time and money because they are the icon species for California. People can see them, they come back to the rivers, people like to fish for them—and so that is where the research dollars go.”
Rainbow trout and steelhead are basically the same species of fish. The difference is in their respective lifestyles. Rainbow trout never leave freshwater habitats. Steelhead, however, which tend to be larger (18 inches in length or longer), lead an anadromous life—they live in the ocean, but return to their native freshwater creeks to spawn.
According to a report by Fish and Wildlife, “Anadromous forms of the trout can convert to resident populations when drought events or damming of rivers blocks their access to the ocean. Conversely, resident-trout populations can become anadromous if ocean access becomes available. … It has been speculated that there is a food-availability-related trigger which determines whether a particular fish emigrates to the ocean or remains in the stream. It may be that if there is abundant food in the stream and a fish is growing at a rapid rate, it will remain in the stream. If food is limited and growth is slow, the fish will have a tendency to emigrate.”
Demko said this adaptive behavior simply makes sense in the fight for survival.
“If you’re getting lots of food where you are at, why go anywhere else?” he said. “It’s like, ‘I’m not going to migrate to the ocean. Life is good right here.’”
Matt Peterson has worked as a researcher for FISHBIO for the past year and a half. He was one of the five divers involved in the survey. The fish count, he said, covered about 4 1/2 miles of the creek.
“Basically, we broke up the stream into different habitat types—pools, ripples and runs,” he explained. “And we also had what we call ‘cascades,’ which are units that we couldn’t sample due to poor visibility for snorkeling or hazardous conditions for the divers.”
He said the survey took 2 1/2 days to complete, compiling numbers from 35 spots—or “units”—on the creek. In 20 of those units, the divers made four passes to make sure they got a full count and then extrapolated those counts to the full survey.
“We’d dive through a unit once and we’d make a count, and then we’d go through it three more times,” Peterson said. “That kind of gives us an indication of how many fish we missed on the first pass. Then you can slightly adjust the numbers upward or downward for the rest of the units.”
The fish acknowledge the divers’ presence, but they don’t panic, Peterson said.
“Generally, they might shift out of the way a little bit when they see you crawl or swim by, but then they generally go right back as soon as you pass,” he said.
Demko said the fish actually cash in on the presence of the divers.
“You are disturbing the insects and aquatic life, and the fish come in and are feeding around you,” he said. “They are following you as you’re moving up the stream, and they are eating and probably thinking, ‘Hey, this is kind of cool.’”
Peterson said the initial data indicates there are a total of about 560 fish of all kinds—native and non-native—per mile of creek. FISHBIO is still crunching numbers to come up with totals for each kind of trout counted in Big Chico Creek.
Without a recent fish count, there’s no way of judging what FISHBIO’s numbers might mean, Demko said.
“It would be good to be able to call Fish and [Wildlife] and go, ‘Hey, what was it last year, or what was it five years ago, or what is it on Deer Creek, or what is it on Butte Creek?’ But nobody does these surveys.
“They do everything related to the chinook and then just assume, ‘Well, if we are improving conditions for chinook, you know, we think we’re going to make more steelhead, too.’ But we just don’t know at this point.”
Scott Huber, who serves as the reserve’s education and research coordinator, also took part in the fish count. He said the school bought the 4,000 acres in 1999 in large part to protect the salmon and steelhead in the creek.
“That was really the impetus behind the purchase of the reserve in the first place,” he said. “We have other threatened [species] or species of special concern [on the property], but it was the salmon and steelhead that were the main drive to set aside that property.”
Demko said the plan is to do surveys three or four times a year for the foreseeable future.
“It’s the long term that brings value to it,” he said. “Right now, we are scratching our heads and going, ‘What does this mean?’”
While FISHBIO received no funding for the initial survey, Demko noted his company did the same thing in Southeast Asia’s Mekong Delta a few years ago.
“This is a smaller scale, but we did the same thing on the Mekong,” he said. “In the future, somebody may come along and this may turn into a bigger study that somebody wants to fund, which is always nice. That is what happened with the Mekong—we started doing the research and then the funding started to follow.
“But here, the point is to make a community-based program. And hopefully, start to answer some questions.”