Largemouth Bass Production in the Delta

Posted on March 19, 2016 by Tom Cannon

I had the unique opportunity to study fish use of shallow inshore waters of the western Delta in 1978-79 and again in 2004-05. One of the biggest differences I noticed after 25 years was the increase in Largemouth Bass production. Mitigation areas where levees were breached allowing tides to enter-and-leave tidal ponds without flow-through were virtual Largemouth breeding factories. Areas where channel entrances had filled in and circulation reduced also were prone to aquatic plant proliferation and an abundance of non-native lake/pond fish including Largemouth, sunfish, and shiner minnows. Flow-through areas and tidal channels with two ends had lower Largemouth production (and more native fishes). Limited tidal circulation also caused prolific amounts of aquatic vegetation including water hyacinth, Egeria, milfoil, Parrots Feather, and Potamogeton. Dense beds of aquatic vegetation also occurred in bays, dead-end sloughs, breached islands, and protected shorelines.

A recent study¹ relates higher Largemouth production to increases in aquatic plants, specifically relating the abundance of young Largemouth to Egeria. They also found young Largemouth more abundant in warmer waters, another feature of backwater areas. Aquatic plants slow currents, capture sediment, and absorb sunlight, which all contribute to warming of shallow waters.

One of the paper’s conclusions related to future habitat restoration:

“While these efforts will expand the largely missing shallow-water habitat in the Delta, a major concern is that increased shallow water area will expand the habitat for Brazilian waterweed and consequently increase the abundance of Largemouth Bass, creating a predation sink for target native fishes (Brown 2003).”

I have some points of disagreement with these conclusions. First, I do not believe the Delta lacks shallow water habitat. The problem, rather, is that too much of existing shallow water habitat is bad habitat more conducive to non-native warm water fish. Second, good shallow habitat along the edges of the bays and rivers has been and continues being lost to riprapping, ship-channel dredging, remnant soft-levee erosion, and filling with sediment.

I concur with the paper that much planned restoration will create more bad habitat. Instead we should be protecting good habitat and converting more of the bad habitat to good habitat.

For more on the subject of Delta habitat restoration see: http://calsport.org/news/cspas-assessment-of-historical-habitat-restoration-in-the-delta/ .

http://www.tandfonline.com/doi/full/10.1080/00028487.2015.1114521 ↩

Feinstein Objects as State and Federal Regulators Hold Back on Delta Exports

Posted on March 12, 2016 by Tom Cannon

The Sacramento Bee ran an article on March 11, 2016 that reported how state and federal water managers have limited Delta exports to protect endangered salmon and smelt. The article also reported that Senator Feinstein had called for increased exports, and quoted a representative from Westlands Water District lamenting the loss of stormwater to the ocean.¹

The facts are that limiting exports to about 6,000 cfs (maximum is 11,400 cfs) under present rules is reasonable given the risks to endangered Winter Run salmon and Delta smelt. As stated in the article, most of remnant Winter Run salmon and Delta smelt are in the Delta.

It was not so long ago that high late winter exports contributed to the decline of both species. In 2001, late winter exports of 8,000-11,000 cfs resulted in high salvage counts of salmon (Figure 1 – up to several hundred per day of Winter Run) in contrast to several hundred for the entire winter in 2016. Delta smelt salvage at South Delta Fish collection facilities reached several hundred per day in 2001 (Figure 2), in contrast to only a total of 12 in winter 2016. Winter 2001 Delta outflows were also high (Figure 3), but exports rules were not as strict.

Also noteworthy is the fact that the multi-agency Smelt Working Group has been recommending even lower exports this winter² because of the record low numbers of smelt and the high risks to smelt from exports.

Restrictions on exports are reasonable and necessary to protect smelt and salmon.

Figure 1. Chinook salmon salvage at South Delta fish facilities in 2001. CVP is federal Tracy facility. SWP is state Clifton Court facility. Export rates are in acre-ft per day. Daily export rate in cubic feet per second (cfs) is approximately 50% of the rate in acre-ft. Winter 2016 salvage totals in contrast total only several hundred. (Source³)

Figure 2. Delta smelt salvage at South Delta fish facilities in 2001. CVP is federal Tracy facility. SWP is state Clifton Court facility. Export rates are in acre-ft per day. Daily export rate in cubic feet per second (cfs) is approximately 50% of the rate in acre-ft.

Figure 3. Delta outflow in winter 2001. Winter 2016 outflow ranged from 10,000 to 66,000 cfs. (Source: CDEC)

Saving Shasta, Trinity and Klamath Salmon in 2016

Posted on March 10, 2016 by Tom Cannon

Salmon in the Sacramento, Klamath, and Trinity rivers depend on maintaining cold water releases from Shasta and Trinity reservoirs through the summer and early fall. Major die-offs of salmon on the lower Klamath and lower Sacramento below Shasta have occurred under conditions of low flows and high water temperatures. In summer and fall of dry years, flows and water temperature cannot be maintained if there is too little reservoir storage, especially the cold-water portion in the bottom of the reservoirs.

The biggest overall threat is that one of the reservoirs will run out of cold water in September and October when salmon eggs and embryos are in the gravel spawning beds in the rivers. For Winter Run salmon in the Sacramento, eggs are in the gravel from June through August. For Klamath-Trinity and Sacramento Spring Run salmon, eggs are in the gravel beginning in September or October; Fall Run eggs in each river are in the gravel beginning in November. In addition to the high water temperatures that can kill any of the eggs, flow reductions in the Sacramento in September and October can also dewater spawning beds after initial spawning in higher flows has occurred.

Government agencies have typically blamed large scale mortality events on the more than a decade-long series of droughts and competition between irrigation demands and water for salmon. But better water management of the Shasta and Trinity divisions of the Central Valley Project by the Bureau of Reclamation and other federal and state agencies can reduce mortality. Massive salmon die-offs in the Klamath, such as the one that occurred in 2002, have been avoided by targeted late summer and early fall cold-water releases from Trinity Reservoir during the past two multiyear droughts. However, failures of the 2014 and 2015 Winter Run broods below Shasta on the Sacramento River were not avoided.

Salmon runs continue to decline during droughts, with hatcheries making up a greater proportion of the runs in both river systems. On the Trinity, wild Spring and Fall Run salmon are at only 32% and 17%, respectively, of restoration program goals.¹ All the Sacramento runs are down, especially the Winter Run, and prognosis for future years is poor based on broodyear failure the past two years. Ocean stocks of Klamath-Trinity and Central Valley salmon are also down this year, which will likely lead to severe sport and commercial fishery restrictions.²

So what measures are in the works for 2016 for protecting salmon? Depending on what precipitation falls in the remainder of winter and this spring, there has been speculation of further restrictions on irrigation deliveries and water supplies, and the allocation of more colder water below the dams for salmon.

In addition to the many actions I identified in previous posts,³ there are several further options that should be considered for 2016 to benefit salmon:

The Klamath-Trinity system should get more emphasis because of potential risks to its salmon, and because it has not fared as well as the Sacramento system in the latest multiyear drought. Shasta Reservoir has reached 60% of capacity as of 1 March (Figure 1). Trinity Reservoir has reached only 40% (Figure 2). This summer, less water could be delivered to the Sacramento River from Trinity Reservoir via Whiskeytown Reservoir to the Sacramento River below Shasta Reservoir than last summer (Figure 3). Water delivered through Whiskeytown is warmer than water delivered from Shasta; reducing deliveries through Whiskeytown would thus save Trinity storage and the cold-water pool supplies in both Trinity and Shasta reservoirs.
Increasing the relative contribution of Trinity Reservoir to the Sacramento River in April and May (and reducing the summer contribution) would save the cold-water pool supplies in both Trinity and Shasta reservoirs. April-May releases from Whiskeytown Reservoir to the Sacramento River below Shasta are colder (<53°F) than the summer releases (58-59°F) (Figure 4) that threaten Winter Run salmon.
Reducing hydropeaking power production during summer would reduce the demands on the cold-water pools. Much of the water released from Shasta, Trinity, and Whiskeytown reservoirs in summer is released in the hot afternoon hours for hydropower production peak demands, leading to warmer waters in Keswick and Lewiston reservoirs. To ensure water that released from these two reservoirs is not too warm for salmon in the rivers below, Bureau of Reclamation operators should optimize daily water deliveries through powerhouses for water temperatures rather than for the value of power.

Figure 1. Shasta Reservoir storage March 2014 to March 2016. (Capacity is 4,552,000 AF.)

Figure 2. Trinity Reservoir storage March 2014 to March 2016. (Capacity is 2,447,650 AF.)

Figure 3. Water deliveries to Whiskeytown Reservoir from Trinity Reservoir via Lewiston Reservoir outlet to Carr powerhouse March 2014 to March 2016. Water then proceeds to Keswick Reservoir immediately below Shasta Reservoir on the Sacramento River. Approximately 100-200 cfs of these flows is also released to Clear Creek, which flows into the Sacramento River below Redding.

Figure 4. Water temperature in Spring Creek Powerhouse June to September 2015.

Spring Run Salmon Restoration in San Joaquin River – Some Questions

Posted on March 8, 2016 by Tom Cannon

Pilot study release of Feather River hatchery smolts at the Golden Gate. (DFW photo)

50,000 Spring Run Chinook smolts from the Feather River Hatchery will soon be released into the San Joaquin River near Merced, as was the case in 2014 and 2015. The action is part of the effort to restore Spring Run to the lower San Joaquin below Friant Dam near Fresno. The smolts each have a coded-wire tag in their nose and an adipose fin clip so their survival can be monitored.

So how have the first two releases fared? Were any collected in Delta surveys, at south Delta pump salvage facilities, in Chipps Island trawls, ocean fisheries, spawning surveys? Data available now from these surveys should be providing early indications of success rates for comparison with other restoration programs. After all, it is an adaptive management program.

Given that the last three years have been dry years especially in the San Joaquin, I do not hold out much hope for the survival of these three years of smolt releases. I hope I am wrong, but information is lacking on the first two releases. Did any make it down the river to the South Delta pumps? Did any make it to the Bay (Chipps Island trawls)?

If not, then some adjustments should be made this year.

Hatchery trucks from Fresno could travel further downstream to the Delta or Bay.
Smolts could be barged from Merced or Stockton to the Golden Gate (see photo above).¹

At a minimum, some early indicators would help us all see some progress for the program and deflect the naysayers who would write off the whole program.²

An Opportunity Missed?

Posted on March 4, 2016 by Tom Cannon

The U.S. Fish and Wildlife Service has released 400,000 Winter-Run Chinook salmon smolts from the Livingston Stone Fish Hatchery into the Sacramento River near Redding. But according to the US Fish and Wildlife Service’s Steve Martarano, “The release won’t occur until we see a significant increase in density and flow in the Sacramento River. It’s based on a rain event.” ¹

Last year Reclamation released some water from Shasta for the “event” (Figure 1). This year there was no such an “event” (Keswick release) (Figure 2). The real question is whether they missed the “real” flow event in January (Figure 3) when storm flows from Cow, Cottonwood, and Battle Creeks downstream of Redding brought flows near Red Bluff to 10,000-40,000 cfs. Why didn’t Reclamation and the Service coordinate release of water from Keswick and the salmon smolts at Redding in late January? Shasta inflows in January reached 40,000 cfs.(Figure 4.) Such a release would have also helped the wild salmon emigrate from their spawning reach at Redding to San Francisco Bay and the Ocean.