Two miles downstream from the City of Riverbank there is an underwater fence in the Stanislaus River.
Boaters passing over it may not realize it is there. But fish — and other creatures such as frogs that swim upstream — are forced to swim around it and through a tank that takes photos.
The technology is accurate and far superior to state sampling techniques used to estimate fish populations such as the Delta Smelt.
The data collected show that the rainbow trout population has increased on the Stanislaus River since 2007 topping 15,000 in recent years while the critical fall Chinook salmon run tied into spawning has more than doubled. Spawning adult numbers after being in the 1,000 to 2,000 range from 2006 through 2011 now consistently surpass 5,000 despite the drought.
The scientific research conducted by FISHBIO over the past decade and underwritten by the South San Joaquin Irrigation District and Oakdale Irrigation District is being used by the two water agencies to discredit state claims that the only way to increase salmon on the Stanislaus River — and the neighboring Tuolumne and Merced rivers — is by ratcheting up unimpaired flows to 40 percent between February and June.
Public input on the state plan is being accepted during a meeting of the State Water Control Board this Friday at 9 a.m. at the Stockton Civic Auditorium. SSJID officials will be among those speaking on the plan.
The state board will also conduct a public hearing on Tuesday, Dec. 20, at 9 a.m. at the Modesto Centre Plaza.
The SSJID and OID argue that scientific research does not support simply running more water down river as an effective way to enhance fish populations. They point to habitat restoration — such as the $1.1 million Honolulu Bar restoration project completed by OID in 2012 — as well as replicating how gravel was naturally dispersed in the river before gold dredging in the 19th century, creating floodplain habitats, controlling water temperature, and addressing non-native predators as has been done in the Pacific Northwest to protect endangered fish on the Columbia River as being much more effective.
The California Department of Water Resources conducted a study in 2014 that determined 95 percent of young salmon and steelhead are eaten by predators before they reach the Delta.
FISHBIO notes non-native bass and other predators lurk in deep pools between Riverbank and the confluence of the Stanislaus and San Joaquin rivers south of Manteca preying on young fish.
Congressman Jeff Denham has been pushing legislation to get various federal agencies to conduct a five-year pilot program to determine the best ways to reduce predation.
The last major dam built in the United States — New Melones that can hold 2.4 million acre feet of water — is seen by some experts as triggering what has been a decades decline in adult salmon on the Stanislaus River. The highest peak since 1950 was an estimated 35,000 plus in 1953. California Department of Water Resources statistics show the fall runs were much more robust in the 1950s, 1960s, and 1970s and then started to taper off after the New Melones dam was built in 1980.
A 1992 federal law known as the Central Valley Project Improvement Act mandates that the Bureau of Reclamation work to rebuild Chinook salmon populations.
The fall run on the Stanislaus, Tuolumne and Merced rivers typically starts toward the end of September and peaks in November before tapering off in December.
For years, the accepted scenario was that mature fish return not just to lay eggs after spending two to five years in the Pacific Ocean but do so in the gravel beds of their birthplace. FISHBIO now points to evidence that many of the trout returning to the Stanislaus to spawn and die did not originate from the Stanislaus but ether on the Merced or Tuolumne or the Sacramento River Basin.
The state plan calls for commandeering 360,000 acre feet of water between February and June each year to bump up the unimpaired flows on the Stanislaus, Merced, and Tuolumne rivers to 40 percent. The state contends that will lead to a maximum of 200 more fish on each of the three rivers on an annual basis.
In exchange roughly 240,000 acres of farmland will be permanently fallowed under drought conditions that exist today, 2,000 to 3,000 jobs tied directly to agriculture would vanish, and annual losses to the economies of San Joaquin, Stanislaus and Merced counties will hit $260 million.
To contact Dennis Wyatt, email email@example.com