In the rugged wilderness of Northern California, a dedicated team of fisheries biologists is waging a critical battle against non-native pikeminnow to protect the iconic salmon of the Eel River. At the heart of this effort are two young heroes, Alex Juan and Jason Shaffer, who have brought their passion and expertise to the frontlines as they work to suppress pikeminnow and give juvenile salmon a better shot at making it to sea.
Alex, originally from the Midwest and now a graduate student at Cal Poly Humboldt, found his calling in the rich tapestry of California's trout and salmon ecosystems. "I could never, in my wildest dreams, have imagined what trout and salmon mean out here,” he says. Leaving behind the more modest fish of his Missouri upbringing, Alex embraced the opportunity to work with the Wiyot Tribe, immersing himself in the fight to safeguard the Eel River's imperiled salmon runs while also beginning his graduate work.
Working closely alongside Alex is Jason Shaffer, another recent arrival to Northern California and graduate of Cal Poly Humboldt, who traded his previous work with non-game fishes for the chance to contribute to the recovery of the region's iconic salmon. "I would be doing this for fun, and I'm doing it for work, so that's great," he says. His enthusiasm is palpable, as he describes the thrill of conducting snorkel surveys and processing data, all in service of the salmon's survival.
Guiding and supporting the efforts of the team is Andre Buchheister, a professor at Cal Poly Humboldt. "Alex and Jason have a toolbox that is very diverse,” Andre explains. “Not only do they understand the system and the field work, but they can then take that data, make sense of it, and provide important information that we need." It is this synergy of field expertise and analytical prowess that makes Alex and Jason such invaluable assets in the fight to protect the Eel River's salmon.
At the heart of their work lies the South Fork Eel River weir, a critical piece of infrastructure designed to impede the upstream migration of the invasive pikeminnow. "The weir's primary goals include blocking and collecting pikeminnow,” Jason explains. The weir is installed in the spring and removed in the fall. Every morning that the weir is in operation, Jason and Alex start their day by visiting it to ensure everything is still in place and to check if there are any fish in the trap box. If pikeminnow are collected in the trap box, they are euthanized and removed from the system. At the end of the day, they revisit the weir to perform the same checks.
Their efforts also extend beyond the weir, as the duo engages in active suppression tactics to target the larger pikeminnow that are more voracious predators of juvenile salmonids. One key suppression method is spearfishing. Alex, Jason, and the team snorkel through different sections of river to identify aggregations of pikeminnow to remove via spearfishing. This technique can require some practice as the pikeminnow are adept at evading capture. “But once you have that practice, like Alex, and you're a laser beam, you can go out and remove a lot of large fish, in not a lot of time,” says Jason. The team awards a trophy to the individual with the most spear fished pikeminnow each year, and last year, Alex won the trophy.
Another tactic is gill netting. This involves setting gill nets across the upstream and downstream ends of a pool known to harbor pikeminnow. The team then swims the nets down the river, herding the fish into the nets. This method can be quite physically demanding, as the crew must dive down to free the nets from obstacles on the river bottom.
E-fishing, or electrofishing, is also employed by the team. They set up nets at the upstream and downstream ends of a pool and then, via boat, they throw an electrical spear into the water to try to shock as many pikeminnow as they can. “Pikeminnow are smart and fast,” Alex explains. “You must get the tip of the spear within three to five feet at most of a fish for it to actually get shocked because if they see the shadow of the spear on the water they scatter. Then once it freezes, you can net it.” In good conditions, the team can remove upwards of 50 pikeminnow in one electrofishing session.
The goal of these active suppression efforts is to target the the larger pikeminnow since they are more voracious predators of juvenile salmonids. By reducing the numbers of these predatory fish, the team hopes to shift the balance in favor of the salmon, allowing more young fish to survive and thrive.
“There are a lot of pikeminnow in the Eel River, and it's an impossible wall to climb doing manual suppression,” Alex says. “But I do think we're already seeing an effect on the larger size classes of pikeminnow, which are the ones that eat salmon and steelhead. Hopefully, by shifting the amount of the larger fish that are in the river, we can shift the number of juvenile salmon that they eat.”
“If we can continually suppress and depress the population, I believe we can return the balance to what it should be,” Jason adds.
While removing pikeminnow from the system, Jason and Alex are also uncovering new information about pikeminnow and salmon in the Eel River through the data they collect. The more they learn, the more questions that emerge helping to better drive a more holistic understanding of this very complex system.
Dams block access to historical spawning and rearing habitats. Downstream, dams alter the timing, frequency, duration, magnitude, and rate of change of flows decreasing habitat quality and survival.
