After the collapse of the Sacramento River’s salmon fishery, many pointed a finger at “ocean conditions” to explain the decline, while many fishermen and activists focused instead on a California Delta they say was crippled by five years of record water diversions.
Now, the National Marine Fisheries Service has issued a new biological opinion (to replace the opinion a judge found wanting), and the information is staggering.
Only 20% of the salmon smolts survive the trip from Red Bluff to the Delta, and once there, the water project’s pumps decimate the remaining smolts – only only 16.5% of the juveniles survive at the state facility and only 35% survive at the federal pumps.
Ouch.
The rest of the report makes for equally grim reading; it’s clear that many of the populations are headed for extinction, and that water is dearly overpromised. You can read more at Dan Bacher’s eye-opening article for Indymedia and at this post on Dan Blanton’s excellent message board.
Here are a few facts excerpted from Blanton’s article:
Staggering losses of salmon and steelhead smolts take place in the Sacramento-San Joaquin Delta, according to the scientists. Indirect losses in the Central Delta were found to be far more significant than losses from direct impingement at the state and federal pumps.
When the cross channel gates on the Sacramento River in the North Delta are open, 65% of the juveniles perish as they are drawn into the Delta interior. When the gates are closed, more than 50% survive.
At the pumps themselves, only 16.5% of the juveniles survive at the state facility operated by the Department of Water Resources and only 35% survive at the federal pumps operated by the Bureau of Reclamation.
Once fish are pulled into Clifton Court Forebay, nearly all of them are lost. The net total loss in the Delta is approximately 60% of the fish entering the system. This number does not include those lost prior to getting to the Delta.
Overall, when the Sacramento River survival of 20% is combined with the Delta survival of 40%, only 8% of the smolts make it to the West Delta!
Interestingly, this opinion appears to provide vindication to retired DFG fishery biologist Frank Fisher, whose arrived at similar conclusions in the early 90s, but whose conclusions were widely derided by water project staff:
The biological opinion also documents the major contribution of high water temperatures on the Upper Sacramento to spawning and egg mortality, as well as the staggering loss of juveniles – 80 percent – between Red Bluff and the Delta. The scenario portrayed by the scientists is very similar to that revealed by Frank Fisher, a now retired DFG fishery biologist, when he documented in 1991-92 the direct correlation between the increase in Delta exports and the decline of Sacramento River salmon.
He documented a “Black Hole of Death” that occurred to migrating salmon smolts in the Delta, due to reverse flows, stranding and entrainment of fish in the pumps caused by increased water exports. Considered a “maverick” at the time, Fisher’s data and conclusions have been vindicated by the draft biological opinion.
You can read Bacher’s whole article here: Delta Exports a Key Factor in Salmon and Killer Whale Declines : Indybay.
Tom: Thanks for posting this. I saw similar reports on the same NMFS draft report in the SacBee and San Jose Mercury News, both of which were highlighting the jeopardy finding for Southern Resident Orcas. I was surprised that both articles almost totally ignored the connection between the water diversions and the salmon survival data. Given policymakers increasingly Delta-limited focus, the NMFS finding of significant impacts even upstream of the Delta should help refocus the debate on the viability of our overall approach to Central Valley water management.
RJ(Quote)