Author Archives: Tom Cannon

Are Striped Bass about to make a comeback?

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Unlike most of the Central Valley native fishes including salmon and smelt, striped bass have an inherent natural advantage or resilience: they are long-lived, have ten or more spawning year-classes in any spawning year, and produce a thousand times more eggs per female. This advantage has come into play after a decade of drought: in the spring of 2016, there are optimal spawning and early rearing conditions for striped bass.

The late April 20-mm Survey results indicate a possible strong year class for stripers compared to recent years. The distribution of larvae in late April 2016 (Figure 1) is the product of moderate normal year Delta outflow with low Delta exports. The 2016 distribution is a dramatic improvement over the critically dry year 2015 (Figure 2), the drought-year 2009 (Figure 3), and also the normal year 2010 (Figure 4).

Normal water year spring Delta outflows that place the Low-Salinity-Zone westward in Suisun Bay, combined with a strong spring plankton bloom, bode well for the growth and survival of young stripers. In contrast, conditions were poor in 2015, when young stripers were confined to the Delta under low Delta outflows and low productivity, and were subject to Delta exports and diversions (Figure 2). Chances of a comeback in the fall-index (Figure 5) remain to be seen, given the lack of summer Delta protections since 1995 under the existing Delta Water Quality Control Plan. Expected high summer exports and low Delta outflows, such as those in normal water year 2010 (the record low fall-index year), may yet preclude a comeback.

Figure 1. Striped bass larvae density distribution in 20-mm Survey #4, Apr 25-28, 2016.

Figure 1. Striped bass larvae density distribution in 20-mm Survey #4, Apr 25-28, 2016.

Figure 2. Striped bass larvae density distribution in 20-mm Survey #4, Apr 27-30, 2015.

Figure 2. Striped bass larvae density distribution in 20-mm Survey #4, Apr 27-30, 2015.

Figure 3. Striped bass larvae density distribution in 20-mm Survey #4, Apr 20-24, 2009.

Figure 3. Striped bass larvae density distribution in 20-mm Survey #4, Apr 20-24, 2009.

Figure 4. Striped bass larvae density distribution in 20-mm Survey #4, Apr 26-29, 2010.

Figure 4. Striped bass larvae density distribution in 20-mm Survey #4, Apr 26-29, 2010.

Figure 5. Striped bass fall index of young striped bass 1967-2013. Not shown are the near record low indices in 2014 and 2015 (59 and 52, respectively).

Figure 5. Striped bass fall index of young striped bass 1967-2013. Not shown are the near record low indices in 2014 and 2015 (59 and 52, respectively).

USBR – Increase Shasta Cold Water Releases

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Water Year 2016 on the Sacramento River has been designated a “Below Normal” year.  Water Year 2010 was also a Below Normal year.  Both years followed multiyear droughts.  In both years, Shasta Reservoir was nearly full at the end of April (2010 was 4.4 maf; 2016 was 4.2 maf).  In early May 2010, Keswick releases were 7500 cfs, and release water temperatures were 50-52°F.  In early May 2016, Keswick releases have been 5200-6200 cfs, and release water temperatures have been 53-55°F.

In April and May, 2010, water temperatures in the upper river remained below 56°F.  In contrast, the warmer, lower flows in 2016 have led to excessively warm water temperatures in the upper Sacramento River.  Water temperatures have reached 60-62°F in the upper river (Figure 1), which are well above the prescribed water quality standard of 56°F necessary to protect spawning salmon and sturgeon.  Winter-run salmon began spawning in late April.  Green and white sturgeon spawn in May.

Figure 1. Water temperature in the upper Sacramento River below Shasta Reservoir in early May 2016. In contrast, water temperatures at these locations during early May 2010 were 56°F or lower.

Figure 1. Water temperature in the upper Sacramento River below Shasta Reservoir in early May 2016. In contrast, water temperatures at these locations during early May 2010 were 56°F or lower.

Reclamation’s CVP operations should strive to maintain the 56°F standard through the spring and summer, as prescribed in the Basin Plan and in the NMFS biological opinion for Shasta operations. This temperature can be achieved by increasing Shasta releases or by lowering the water temperature of releases using the temperature control tower/device (TCD) at the dam, or by a combination of these elements. In the last few days, Reclamation has increased releases and has added colder water, resulting in slightly colder Keswick releases (Figure 1). Reclamation has decreased the temperature of releases by opening one the six middle outlets of the Shasta Temperature Control Device (Figure 2). However, downstream temperatures remain high, because air temperatures and water diversions downstream are also increasing.

While there is some logic behind Reclamation’s decision to minimize reservoir releases to save Shasta storage, it is inappropriate to jeopardize endangered fish in the upper Sacramento River with excessively warm water this year, given the abundance of cold water in the reservoir. 1

With Shasta releases expected to increase soon to meet increasing irrigation demands, it will be imperative that water temperatures upstream of Red Bluff remain below 56°F to protect spawning salmon and sturgeon and their young into and through the summer.

The “official” temperature target and control point since April 15, 2016 have been 58°F at Redding (station CCR). In 2010, the target temperature was 56°F, and the control point was at Jellys Ferry (RM 267), 20 miles downstream of Redding. The State Board and NMFS should immediately change the target temperature to 56°F, and move the control point at least downstream to Jellys Ferry. Preferably, the compliance point should be further downstream at Red Bluff, to be in compliance with the NMFS biological opinion (56°F at Red Bluff – RM 243). The Basin Plan puts the compliance point further downstream still, (56°F at Hamilton City – RM 200). 2

Following catastrophic losses of winter-run in the Sacramento below Shasta during the past two years, it is imperative to meet the summer water temperature goals as prescribed in the NMFS biological opinion. The Shasta cold-water pool and storage available are more than adequate to meet these objectives.

Figure 2. Shasta Dam’s temperature control tower/device or TCD has multiple options for releasing water from the reservoir. One middle outlet was recently opened to reduce the temperature of the water released to the Sacramento River. (Source: USBR MidPacific Division)

Figure 2. Shasta Dam’s temperature control tower/device or TCD has multiple options for releasing water from the reservoir. One middle outlet was recently opened to reduce the temperature of the water released to the Sacramento River. (Source: USBR MidPacific Division)

  1. A disproportionate amount of Sacramento River Delta inflow this spring has come from Oroville Reservoir (Feather River) and Folsom Reservoir (American River) storage releases. Excessive use of Folsom storage to meet Bay-Delta needs could lead to loss of its cold-water pool this summer and greater mortality of over-summering juvenile salmon and steelhead in the American River. ↩
  2. A plan for summer operations from Reclamation is due by May 15, 2016 ↩

Rare Bay-Delta Spring Bloom may benefit Smelt

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A rare Bay-Delta spring plankton bloom in 2016 may benefit longfin and Delta smelt (and other fish).  The bloom (a condition in which chlorophyll concentrations consistently exceed 10 micrograms per liter of water) commenced in late April.  Geographically, it extended from Suisun Bay up into the Delta to Rio Vista on the Sacramento River and to near Stockton on the San Joaquin River (Figure 1).

Figure 1. Bay-Delta phytoplankton bloom late-April to mid-May 2016. Plots show chlorophyll concentrations at selected stations from mid-April to mid-May. Source: CDEC.

Figure 1. Bay-Delta phytoplankton bloom late-April to mid-May 2016. Plots show chlorophyll concentrations at selected stations from mid-April to mid-May. Source: CDEC.

The bloom coincided with a drop in previously high early spring Delta inflow and outflow, as well as with low exports and the implementation of San Joaquin River pulse flows.1 Delta outflows were moderate, relatively steady, and higher than in recent drought years, and consistent with a “normal“ year pattern (Figure 2). San Joaquin River pulse flows occurred after mid-April (Figure 3). The Low Salinity Zone or LSZ (0.5-6 ppt) was located in Suisun Bay. X2 (2 ppt) migrated with the tides from Honkers Bay (northwest of MAL) to Sherman Island (northeast of ANH) within eastern Suisun Bay. The head of the LSZ (500-1000 EC) and the bloom extended upstream to Rio Vista on high tides (Figures 4 and 5). Water quality standards (D-1641) that require 14-day average X2 to be at Chipps Island (MAL) or further west helped to ensure consistent Delta outflow.

Longfin smelt concentrated near X2 and may benefit from plankton bloom (Figure 6). Remaining Delta smelt may also benefit as they too concentrate near X2. Maintaining the LSZ and X2 in Suisun Bay is generally thought to promote Bay-Delta productivity and higher smelt survival. In the past four years of drought, the LSZ and X2 during spring and summer have generally been upstream of Suisun Bay, in the Delta.

Figure 2. Delta outflow mid-April to mid-May 2016. Source: CDEC.

Figure 2. Delta outflow mid-April to mid-May 2016. Source: CDEC.

Figure 3. San Joaquin River inflow to the Delta at Mossdale April-May 2016. Source: CDEC.

Figure 3. San Joaquin River inflow to the Delta at Mossdale April-May 2016. Source: CDEC.

Figure 4. Bottom salinity in Sacramento River several miles downstream of Rio Vista in early May 2016. Source: CDEC.

Figure 4. Bottom salinity in Sacramento River several miles downstream of Rio Vista in early May 2016. Source: CDEC.

Figure 5. Chlorophyll concentrations at Rio Vista in early May 2016. Source: CDEC

Figure 5. Chlorophyll concentrations at Rio Vista in early May 2016. Source: CDEC

Figure 6. Catch distribution of young Longfin smelt in late April 2016 along with extent of plankton bloom (red boundary). Smelt were concentrated (larger green dots) near X2 in central and eastern Suisun Bay. Source: CDFW 20-mm Survey.

Figure 6. Catch distribution of young Longfin smelt in late April 2016 along with extent of plankton bloom (red boundary). Smelt were concentrated (larger green dots) near X2 in central and eastern Suisun Bay. Source: CDFW 20-mm Survey.

  1. The bloom also occurred after a winter of moderate Yolo Bypass flood spills that may have contributed nutrients to fuel the bloom. Elevated Bypass flows continued through mid-April. ↩

Water Quality Standards Optional

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On May 5, I reported on the “chumming of stripers” with the late season release of millions of hatchery smolts into the warm, low flows of the Sacramento and Feather rivers.  So what more could the state and federal managers do to improve conditions for our salmon, steelhead, smelt, sturgeon, and other fish resources?    They could start by obeying and enforcing the rules already on the books.

Because of the restrictions placed on South Delta state and federal water project exports by rules governing San Joaquin River steelhead, exports are now restricted to no more than about 2500 cfs.  Such low exports at this time of year have in fact been the norm for the past 20 years under water quality standards and endangered species biological opinions.  The steelhead biological opinion for the San Joaquin is relatively restrictive this year because of the San Joaquin’s dry-year designation.

So what is the problem?  Because it cannot export, the US Bureau of Reclamation is releasing minimum flows from the warm surface waters of a full Shasta Reservoir.

This causes violations of the standards for Sacramento River water temperature.  The upper Sacramento River standard of 56°F has been violated: water temperatures have been running 60-62°F.  The lower river standard of 68°F has also been violated. water temperatures are running 70-72°F.  These conditions contribute to:

  1. Poor survival adult winter and spring run salmon in their peak migration perio;,
  2. Poor egg survival of winter run in the first month of spawning season;
  3. Poor late fall run salmon fry survival;
  4. Poor sturgeon egg survival during their peak spawning season; and
  5. Poor hatchery and wild smolt survival to the Bay.

The Delta outflow-salinity standard under D-1641 requires salinity at Chipps Island to be no more than 2.64 mmhos on a 14-day running average; the most recent 14-day average is above 3.0 mmhos.  With minimal Sacramento River inflow, Delta outflow has reached as low as 8,000 cfs in early May 2016.  These conditions contribute to:

  1. Poor migratory flows for adult and juvenile fall, winter, and spring run salmon, steelhead, and green and white sturgeon;
  2. Poor longfin and delta smelt survival; and
  3. Poor Delta and Bay productivity.

The standards (rules) governing the Central Valley rivers and Delta are there for a reason: to protect water quality, fish, and ecosystem function.  They do not contain the caveat: ‘Comply when convenient.’  They don’t have an exception that reads: ‘No Exports?  No Problem.  Release what meets your sense of order.’  With such gross disregard for the rules, it is no wonder our fisheries resources are in such a poor state.

Water temperature in past month at Bend Bridge near Red Bluff. Note: in 2010, the last below normal water year, water temperature did not exceed 58°F during first 12 days in May.

Water temperature in past month at Bend Bridge near Red Bluff. Note: in 2010, the last below normal water year, water temperature did not exceed 58°F during first 12 days in May.

River flow in past month at Wilkins Slough below Colusa on middle Sacramento River. Note: flow was 7000-13,000 cfs during first 12 days of May 2010, the last below-normal water year

River flow in past month at Wilkins Slough below Colusa on middle Sacramento River. Note: flow was 7000-13,000 cfs during first 12 days of May 2010, the last below-normal water year

Delta outflow in past month. Note: outflow in the first 12 days of May 2010, the last below normal year, was 20,000-30,000 cfs.

Delta outflow in past month. Note: outflow in the first 12 days of May 2010, the last below normal year, was 20,000-30,000 cfs.

Hatcheries Release Salmon Smolts into Low Flows and Warm Water – April and early May, 2016

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April 13. CBS San Francisco reports:

The federal government is funding the release of millions of Baby Chinook salmon into Battle Creek at the Coleman Federal Hatchery outside Red Bluff. Brett Galyean, deputy project leader at Coleman Federal Hatchery, said, “It’s a big day. It’s the first time in two years that we were able to release all the fish on station…. Because of the drought the last two years, the environmental conditions in the Sacramento River — warm water, low flow — caused us to truck fish.”… However, of the 12 million fish released, only one percent are expected to return to Battle Creek in three years to spawn.

April 29. Recent fishing report states:

This spring’s striper fishing on the Sacramento River has been going very well with daily limits of large Sacramento River striped bass. Most of the action has been from Colusa downriver through Verona as the Sacramento River is very low due to minimal releases from Keswick Dam and high volumes of irrigation pumping from the lower Sacramento River. Stripers mostly 18 to 24 inches are coming in daily with some very large female stripers 15 to 25 pounds coming in as well. Drifting live jumbo minnows has been working best in the daytime while black worms or white swim baits are working at night. The Coleman National Fish Hatchery has released the remaining 6 million fall-run juvenile salmon smolt into the Sacramento River. With low flows coupled with the massive irrigation pumping, the lower Sacramento River from Butte City downriver through Verona is extremely low, leaving exposed sand and gravel bars across the river. This is setting the stage for an incredible striper fishing as the smolts arrive in the lower Sacramento River. Striper fishing should be incredible as the stripers feed day and night on the hatchery salmon smolt just like last month when the first round of hatchery Sacramento River salmon smolt were released. Sacramento fishing.com fishing guide Dave Jacobs has witnessed countless striper boils as the spawning stripers have fed around the clock on the salmon smolts from Butte City downriver through Verona.

May 1. Yet another fishing report notes:

The striper action has been incredible for the past several weeks. While many of the stripers are post spawn they are hanging out and destroying recent salmon plants coming out of the hatcheries…. Before the past weekend, he found great action on the Feather River, but heavy boat traffic over the weekend slowed down the Feather since an armada showed up. Salmon smolts were released in the Feather this past week, and the combination of low flows and clear water made for a killing zone for the smolts…. The bite lasted until most of the baby salmon made it to the Sacramento River, and I was able to follow them down the Sacramento a couple of miles until the fishing got tough…. The California Department Fish and Wildlife hatchery on the Feather river is planning on releasing their final stock of 1 million into the Feather river instead of trucking them around the river and Delta pumps to the Suisun Bay. The Federal hatchery on Battle creek released 4 plus million salmon fry this past week and will dumping an additional 1.9 million fall run fish into Battle Creek this coming Friday. The is [sic] opposed to these releases due to the current lower flows and clear water. With high numbers of spawning stripers and low / clear flows most of these fish will never make it as far as Sacramento. Past studies have shown that 94% of hatchery salmon released on the upper Sac never make it to San Pablo bay in these conditions.

May 2. SacBee Fishing continues the theme:

SACRAMENTO RIVER, Red Bluff to Colusa – Salmon smolts have been released from Coleman National Fish Hatchery, and are expected to fuel a hot striper bite from Butte City to Verona. The river is dropping, which caused many of the stripers to drop downstream last week. Anglers now expect stripers to move upriver to feed on the salmon smolts.

Sacramento River Conditions

The Sacramento River water quality Basin Plan objective requires no water temperature greater than 56°F upstream of Hamilton City and no temperature greater than 68°F upstream of Sacramento. Water temperature Red Bluff (upstream of Hamilton City) has already reached a daily average of 62°F, well above the required limit (and this with Shasta full of cold water). Water temperatures below Hamilton City have reached 69°F (at Wilkins Slough). Downstream-migrating smolts are stressed and more vulnerable to predation as water temperatures approach 60°F, yet managers continue to release hatchery smolts from the Battle Creek and Feather River hatcheries. Adult winter-run and spring-run Chinook salmon, now migrating upstream in the Sacramento River, are also being stressed by water temperatures greater than 65°F. The 60-65°F range is optimal for striped bass feeding and metabolism. ARE THE HATCHERY SMOLTS SIMPLY CHUM FOR STRIPERS???

Sac at Red Bluff