Concerns over the fate of an estimated 1,500 Chinook salmon congregating in the mouth of the Shasta River have slackened somewhat since last week.
Fish and Game biologist Mark Pisano reported that an increase in river flow levels over the weekend has helped create more favorable conditions for the migrating salmon.
“I am feeling more comfortable that the fish will be OK in the canyon until additional flow releases are made, which will probably be Friday or maybe as early as Thursday,” Pisano said on Tuesday morning.
Pisano also noted that recent drops in air temperatures also factor in favorably, as they contribute to river cooling, as well.
“The fish are still in the pools,” said Pisano, referring specifically to a handful of key pools, roughly in the vicinity of Pioneer Bridge, that contain several hundred fish each.
Through radio telemetry and a fish counting weir, biologists have been able to determine the location and overall number of the fish in the river system.
The recent influx in water to the system is due to an effort by some irrigators to forego their allotted water rights for this last week of the irrigation season.
Adriane Garayolde of the Shasta Valley Resource Conservation District said that, beginning last Friday, her organization has made an effort to put the word out about the situation, encouraging irrigators to reduce their water take if possible.
Shasta River Watermaster Ira Alexander, who is entrusted with the task of overseeing the water apportionment process for the California Department of Water Resources, reported on Saturday that he knew of six irrigators who were foregoing their diversions in an effort to help provide the additional flow.
Alexander emphasized that it is his job to enforce the Shasta Decree, and that he has no authority to regulate the flow.
“We can, however, talk with Fish and Game about who to talk to and (give them information) about who is diverting,” said Alexander, expressing his hope that the extra “slug” of water released would assist the stalled salmon.
Amy Hoss of the Nature Conservancy reported that Big Spring Ranch had shut off their irrigation, contributing an estimated 13 cfs to the depleted river.
RCD representative Garayolde applauded the efforts of the irrigators who had agreed to curtail or cease their irrigation.
She noted that because of recently installed variable speed irrigation pumps, an RCD project, it is now possible for some irrigation districts to reduce their take. “It used to be a matter of just being on or off,” she said.
Klamath runs earlier and larger
Fish and Game fisheries biologist Morgan Knechtle reported that the Shasta River Chinook run has come earlier and stronger this year.
Knechtle reported that the numbers have been consistant with projections for the entire Klamath system, which he said is forecasted to be over 130,000 returning salmon.
As a regional Klamath Project coordinator, Knechtle monitors the fish counting program in the middle Klamath tributaries, which includes the weir at the mouth of the Shasta.
Knechtle and his crew have been monitoring the salmon build-up since the fish first started appearing on Sept. 4. “We are concerned about the fish and the conditions that they are being subject to,” he said, noting that as they maintain their holding pattern in the lower canyon and the school grows in numbers, they are more susceptible to disease.
“If the densities (of fish) go up, the chance of spreading ich or columnaris increases,” he said, referring to two common fish diseases. “These were what affected the salmon in the main stem fish kill incident in ’02,” he continued, referencing the massive fish kill that resulted in the death of an estimated 60,000 salmon.
Knechtle and his crew have kept their eye on fish numbers and location, as well as water temperatures, as the canyon build-up has unfolded. “The river has been warm but not critically warm,” he said last week. He said the 71F is high but not unusual.
“We have been observing an additional 80 to 150 fish entering the system every day,” he added.
Wading the river to inspect one of the fish packed holes, Knechtle stopped to sample a dead fish.
Spawning mortality, he noted, is a natural occurrence, something that occurs with any salmon migration. He said that his crews had recovered a handful of dead salmon and that this is well within the parameters of a natural run.
Upon locating the fish, Knechtle took measurements of the 12 to 15 pound Chinook, as well as extracting a sample of the fishes odilith bone (located in the inner ear) “This bone is like rings on a tree,” he explained. “It will tell you how old the fish is and each ring also provides information about the water quality… we are looking for chemical signatures,” he said, saying that these signatures help biologists understand migration patterns and other useful information about the fish.
Record low flows
The past month has seen several record low river flows on both the Shasta and the Scott Rivers, prompting concern by agency officials and environmental groups.
Pisano noted that irrigation season ends on Oct. 1.