Welcome to the California Fisheries Blog

The California Sportfishing Protection Alliance is pleased to host the California Fisheries Blog. The focus will be on pelagic and anadromous fisheries. We will also cover environmental topics related to fisheries such as water supply, water quality, hatcheries, harvest, and habitats. Geographical coverage will be from the ocean to headwaters, including watersheds, streams, rivers, lakes, bays, ocean, and estuaries. Please note that posts on the blog represent the work and opinions of their authors, and do not necessarily reflect CSPA positions or policy.

Are Hot Rivers in Summer the New Norm?

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The much anticipated salmon season opener on the Sacramento River will be a bust, just as it was last year.

USA Fishing reports on July 15, 2017: “The Central Valley rivers open to salmon fishing on Sunday July 16th. The good news is that reservoirs are full and we have cold water and much higher releases than we have seen (for the opener) in years.”

The sad news is that despite record inflow to reservoirs, the “new norm” in the lower Sacramento River is low water, high water temperatures, and no salmon during summer. This “new norm” is a consequence of the fact that federal and state regulators have changed the rules as they are applied on the ground, with little or no public input. Federal EPA and State water quality standards are no longer being enforced. The summer 68oF limit for the lower Sacramento River between Red Bluff and the Delta no longer applies. The “new norm” is 72-75oF (22-24oC), as is evident in Figures 1 and 2, below. This new norm is in direct contrast to 2006 and 2011, the last two wet years (Figures 3 and 4). The apparent reason is an absolute prioritization of using Shasta Reservoir storage for water contractors and winter-run salmon. Fall-run salmon, the backbone of ocean and river salmon fishing alike, no longer rate protection. Shasta Reservoir is just about full, but the Bureau of Reclamation is using none of the water stored there to maintain water temperatures in 200 miles of the lower Sacramento River.

Why are flows and water temperatures important in the lower 200 miles of the Sacramento River? In spring, millions of upper river hatchery and wild salmon and steelhead smolts pass through the lower river on their way to the ocean. Also in spring, white and green sturgeon spawn and rear in the lower river. Adult winter-run and spring-run salmon also pass upstream through the lower river during the spring on their way to upper river and tributary spawning grounds. In summer, adult fall-run salmon begin their upstream run in July, with a peak in August-September. The lower river is home to rearing juvenile salmon, steelhead, and sturgeon all summer; high water temperatures and low flows are detrimental to their survival and favorable to predators. High water temperatures and low flows in the river also increase the likelihood of higher water temperatures and lower flows through the Delta to the Bay, leading to poorer survival of longfin smelt, Delta smelt, and other native Delta fishes.

Figure 1. Water temperature (daily high and low) and flow at Wilkins Slough of lower Sacramento River, June-July 2017. Source for all figures: https://waterdata.usgs.gov/nwis/

Figure 2. Water temperature (daily high and low) and flow at Verona of lower Sacramento River, June-July 2017.

Figure 3. Water temperature (daily high, median, and low) and flow at Wilkins Slough of lower Sacramento River, June-July 2011.

Figure 4. Water temperature (daily high and low) and flow at Wilkins Slough of lower Sacramento River, June-July 2006.

Splittail Status end-of-June 2017

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Last time I posted on splittail, it appeared that the species remained relatively abundant (though declining) in its core population centers in the Bay. I was concerned about population recruitment during the 2012-2015 drought and whether there were sufficient adults remaining to bring about a strong brood year in wet year 2017. The traditional summer and fall surveys will be the best indicator of success. At the end of spring, the best interim indicator is splittail salvage at south Delta SWP and CVP export facilities. In wet years, south Delta export salvage likely best reflects San Joaquin River splittail production.

I compare salvage in 2011 with 2017 in Figures 1 and 2 for the SWP and CVP, respectively. These were the only wet years since 2006. Wet years provide good spawning and rearing conditions for splittail. These conditions often create strong year classes of juvenile and adult splittail as shown in summer and fall fish surveys in the Delta and the Bay.

Though the density of juvenile splittail in salvage is lower in 2017 than 2011, winter and early spring flows were higher in 2017, which could have led to broader dispersal. Very high late winter and early spring flows in the lower Sacramento River system including the Yolo Bypass may have transported north-of-Delta splittail production directly to the Bay, bypassing the south Delta and its export facilities. Spring flows in the two years were similar in magnitude when young splittail traditionally move downstream through the Delta toward the Bay. It remains to be seen whether the difference in salvage plays out as a discrepancy in recruitment in the Bay populations. Local spawning recruitment in the Napa and Petaluma rivers and in Suisun Bay/Marsh could be strong in years like 2017 and could make up for lower recruitment from the Sacramento and San Joaquin river valleys. The primary concern is long term trends in the core adult population centers in the Bay that for now remain strong.

Splittail Salvage at SWP Byron Facility

Figure 1. Splittail salvage density (number per 10,000 cubic meters exported) at State Water Project Delta export facility in May and June 2011 and 2017.

Splittail Salvage at CVP Tracy Facility

Figure 2. Splittail salvage density (number per 10,000 cubic meters exported) at Central Valley Project Delta export facility in May and June 2011 and 2017.

Improving Hatchery Salmon Survival

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One way to effectively increase the California coastal salmon population is to increase survival of Chinook salmon smolts released by the three large Sacramento Valley hatcheries. These three hatcheries produce nearly 30 million fall-run smolts a year and account for 70-90% of California’s ocean and river fishery catch. A one percent smolt survival leads to 300,000 adult returns to the fisheries and escapement to spawning rivers. Doubling survival to two percent would increase returns to 600,000 adults. With survival at or below one-half percent in recent drought years, returns have fallen to near 100,000.1

How can we get survival back to one or even two percent or higher? Fortunately at least a quarter of the smolts are tagged to allow estimates of their survival and contributions to fisheries and escapement back to spawning rivers. Survival estimates are now available for hatchery smolts released up to 2013. Figures 1-3 show a summary of survival from the three largest hatcheries for salmon brood years 2008-2012 (smolt releases from 2009-2013). I drew the following conclusions from the figures:

  1. Releasing smolts in the spring of drought years in the rivers near the hatcheries provides only about a half percent survival in drought years (release years 2009 and 2013). Survival improves to 1-3 % in wetter years (release years 2010 and 2011), likely a consequence of better transport flows, lower water temperatures, and lower predation because of higher turbidity.
  2. Poor ocean survival (2008-2009, and 2014-2015) likely contributes to poor survival (percent returns) for those brood years rearing in the ocean under poor conditions.
  3. Transporting the salmon smolts via truck to San Francisco Bay for release into acclimation pens markedly increases survival in dry and wetter years into the 1-3% range. The benefit appears smaller in the wetter years, but remains significant and substantial. The Feather and American state hatcheries continue transporting the bulk of their smolts in recent years, while the federal Coleman hatchery has greatly reduced the practice because of apparent higher straying rates.
  4. The program of releasing Feather smolts to coastal bay pens sharply increases returns to coastal fisheries. However, the threat of these fish straying to coastal streams with different genetic stocks now limits this practice.
  5. Lastly, barging fish from near their hatcheries to the Bay shows much promise. Barging may triple survival in drier years when survival is one percent or less, and may reduce straying. A multiyear study of barging is currently underway.

In conclusion, adult salmon stocks in coastal waters continue to benefit from transporting smolts to Bay net pens. Further benefits may derive from barging the smolts 100 to 200 miles to the Bay. Potential benefits of barging over trucking include higher survival and reduced straying. Release of hatchery smolts directly to Sacramento Valley rivers near the hatcheries provides minimal survival especially in drier years. Increasing survival factors like augmenting flow releases from reservoirs at the time of river hatchery releases may improve survival, but trucking and barging appear necessary to keep ocean and river fisheries afloat in the short term.

Figure 1. Feather River hatchery fall-run salmon return rates by release method for brood years 2008-2012 (release years 2009-2013). Source of data: http://www.rmpc.org/

Figure 2. American River hatchery fall-run salmon return rates by release method for brood years 2008-2012 (release years 2009-2013). Source of data: http://www.rmpc.org/

Figure 3. Sacramento River (Coleman) hatchery fall-run salmon return rates by release method for brood years 2008-2012 (release years 2009-2013). Source of data: http://www.rmpc.org/

Delta Status End of June 2017

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Despite the fact that it is a record wet year with abundant spring snowmelt, early summer conditions in the Delta in 2017 are not looking good.  Rapidly falling Delta inflows and a late June heat wave have led to salt water intrusion and extremely warm water temperatures detrimental to salmon and smelt throughout the Delta.

Notably, lower Sacramento River flows at Wilkins Slough upstream of the mouth of the Feather River are down about a third compared to the last Wet year, 2011 (Figure 1).  Flow is only about 7000 cfs and water temperatures are 73-75°F, well above the water quality standard of 68°F.  Winter-run and spring-run adult salmon will not move up the river at these temperatures.  Why is flow so low?  Good question.  Shasta is nearly full but releases are down about a third for a wet year at 8000 cfs.  In contrast, the San Joaquin River flow coming into the Delta near Stockton is 13,000-15,000 cfs, with water temperatures of 71-73°F.

Feather River flow contributions to the Sacramento River are very low (Figure 2).  Yuba and American River flow contributions remain strong at about 4000 cfs each.

Overall Delta outflow in late spring 2017 is lower than Wet year 2011 (Figure 3).  Delta inflow is approximately 34,000 cfs, with about equal contribution from the Sacramento and San Joaquin rivers. Delta exports have been maximum through June at 11,400 cfs.  With in-Delta use taken into account, Delta outflow is estimated at 19,000-21,000 cfs. (Note: USGS measured outflow about 14,000 cfs with tides taken into account on June 22.)

With sharply falling Delta inflow and outflow, high exports, and the heat wave, the Delta is unusually warm at 72-75°F. Such temperatures are detrimental to juvenile smelt, salmon, and sturgeon survival.  Juvenile salmon have been present in the Delta well into June on their seaward migrations (Figure 4).

 With falling Delta inflow and high exports, the Delta is stagnating and salt water is intruding at the west end at Chipps Island (Figure 5).  The Low Salinity Zone with the few Longfin and Delta smelt that are left is moving into the Delta on incoming tides.  The water temperature at the head of the LSZ is already 72°F (Figure 6).  Higher temperatures would be very detrimental to surviving smelt and seaward-moving juvenile salmon.  The further east the LSZ moves, the warmer it usually becomes.

There is a consistent late spring pattern in the operation of State Water Project and Central Valley Water Project in which they cut reservoir releases while exporting the remnant freshwater pool in the Delta.  Even in this very wet year we are again witnessing this water supply control strategy.  The problem is the rivers get too warm even to the point of violating water quality standards.  With less water and warmer water entering the Delta, the Delta also becomes too warm.  Delta water quality standards and endangered species permits are supposed to keep this from happening.  Come July 1, conditions will only get worse, especially as snowmelt declines and San Joaquin flows drop sharply.

What can be done?  Both Shasta and Oroville reservoir releases are lower than normal.  Just keeping their cold-water releases near normal and allowing the flows to pass through the Delta would nearly fix the problem.  Exports in the 1970’s and 1980’s were limited to 6000-9000 cfs in June-July of Wet years.  Reducing the present export level of 11,000 cfs would also help.  These would be very reasonable actions given present water supplies in the Central Valley.

Figure 1. Flow in the lower Sacramento River at Wilkins Slough in late spring of 2011 and 2017.

Figure 2. Lower Feather River flow at Gridley upstream of the mouth of the Yuba River.

Figure 3. Delta outflow in late spring 2011 and 2017.

 

Figure 4. Salmon salvage at Delta fish facilities in June 2017. Source: https://www.wildlife.ca.gov/Conservation/Delta/Salvage-Monitoring

Figure 5. Salinity (EC) at Mallard Island gage near Chipps Island (eastern end of Suisun Bay) in June 2017.

Figure 6. Water temperature at Mallard Island gage near Chipps Island (eastern end of Suisun Bay) in June 2017.

Sometimes it doesn’t take a lot of water.

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In a May 29 post, I discussed how a small diversion of cold water from the West Branch of the Feather River sustains the Butte Creek spring-run Chinook salmon, the largest spring-run salmon population in the Central Valley. In a May 8 post, I described how the Shasta River, despite its relatively small size, produces up to half the wild fall-run Chinook salmon of the Klamath River. In both examples, it is not the amount of water, but the quality of the water and the river habitat that matters. In the former case, man brought water to the fish. In the latter, man returned water and habitat to the fish.

While both examples are remarkable given the relatively small amount of water involved, the relatively small restoration effort required on the Shasta River and the minimal effect on agricultural water supply make it almost unique.

Just take a look at the present late May 2017 hydrology of the Klamath River (Figure 1). There was only 140 cfs flowing in the lower Shasta River. At the same time, there was 25,000 cfs flowing in the lower Klamath, 2000 cfs in the upper Klamath below Irongate Dam, and 2000 cfs in the Scott River. What is different is that most of the Shasta flow is spring fed, some of which is sustained through the summer. Of the roughly 300 cfs base flow in the river in late May 2017, about 200 was from springs (Figure 2). By mid-summer, flow out of the Shasta River into the Klamath will drop to about 50 cfs, with agricultural diversions from the Shasta at about 150 cfs. October through April streamflow is generally sufficient to sustain the fall-run salmon population. Summer flows are no longer sufficient to sustain the once abundant Coho and spring-run Chinook salmon.

Figure 1. Lower Klamath River with late May 2017 streamflows in red. Note Shasta River streamflow was only 140 cfs near Yreka, California. Data source: CDEC.

Figure 2. Selected Shasta River hydrology in late May 2017. Roughly 150 cfs of the 300 cfs total basin inflow is being diverted for agriculture, with remainder reaching the Klamath River. Red numbers are larger diversions. The “X’s” denote major springs. Big Springs alone provides near 100 cfs. Of the roughly 100 cfs entering Lake Shastina (Dwinnell Reservoir) from Parks Creek and the upper Shasta River and its tributaries, only 16 cfs is released to the lower river below the dam. Red numbers and arrows indicate larger agricultural diversions. Up to 15 cfs is diverted to the upper Shasta River from the north fork of the Sacramento River, west of Mount Shasta.