Delta June 2019

Water year 2019 has been a very wet year.  Yet salmon and sturgeon survival was compromised by low flows and high water temperatures in the Sacramento River this spring.1 Young salmon survival has been further compromised by low flows, high exports, and high water temperatures in the Delta this past June.

Many of the wild smolts produced in Central Valley rivers this year entered the Delta in May and left (or died) by the end of June, as observed in Delta export salvage collections (Figure 1).  Many of the wild smolts captured in the south Delta likely originated from San Joaquin tributaries.  South Delta exports were near maximum at 10,000 cfs, about 70-80% of San Joaquin inflow to the Delta and 20% of total Delta inflow.  The high exports caused lower flows and associated high water temperatures (>20oC) in the Delta channel of the lower San Joaquin River (Figure 2), and contributed to similarly high temperatures in the lower Sacramento River channel (Figure 3).

The high Delta water temperatures (>20oC) compromised the survival of the salmon smolts in June.  Reducing the export limit to 5000-6000 cfs in June of this wet year would have kept the water temperature near a 20oC limit.  The water quality standards in the 1980’s and 1990’s under D-1485 had a 6,000 cfs June export limit.  In the past two decades under D-1641, the June export limit changed to 65% of total inflow.

New Delta water quality standards should provide export limits and inflow/outflow minimums that protect salmon through the spring months.

Figure 1. Chinook salmon salvage at south Delta export facilities in 2019. Note the prevalence of wild (non-hatchery) smolts in May-June.

Figure 2. Water temperature and tidally-filtered flow at Jersey Point in the lower San Joaquin River channel of the Delta in June 2019.

Figure 3. Water temperature and tidally-filtered flow at Rio Vista in the lower Sacramento River channel of the Delta in June 2019.

 

 

Sacramento River Salmon Opener Compromised

The California Department of Fish and Wildlife announced in May that the salmon season on the Sacramento River would commence below Red Bluff on July 16, with high expectations and expanded limits.

 “California’s inland salmon anglers can look forward to a better salmon fishing season than last year. A projected return of 379,600 spawning Sacramento River fall-run Chinook Salmon to Central Valley rivers has allowed fishery managers to return to a two salmon daily limit with four salmon in possession. This is a welcome increase over last year’s regulations, which restricted anglers to one salmon per day and two in possession.”

Yet despite near record water and a full Shasta Reservoir, the federal government is compromising the run with high water temperatures from low reservoir releases and high river diversions that violate state water quality regulations and water right permit requirements.

River flow near Red Bluff is just above 12,000 cfs (Figure 1), about 1000 cfs below average for this time of year.  River flow in the river a hundred miles downstream, upstream of the mouth of the Feather River, is just below 7000 cfs, also slightly below average (Figure 2).  The flow difference between the two locations reflects water deliveries to federal water contractors near 5000 cfs.

The high diversions and low flows result in high water temperatures in the lower river (Figure 3) that will compromise the fishery opener as well as survival and egg production of this fall’s spawning run.  The salmon run is already in a long-term decline (Figure 4) from poor water management and violations of standards and permits conditions.

Why allow the federal government to squeeze out more of California’s precious water and salmon?  Increasing Shasta releases or reducing diversions, or a combination thereof, by about 1000-2000 cfs should protect the migrating salmon and provide a better fishery opener.  With triple-digit weather forecasted for the latter half of July, it is imperative that river flows be increased.

Figure 1. Sacramento River flow near Red Bluff June-July 2019.

Figure 2. Sacramento River flow near Grimes at Wilkins Slough June-July 2019.

Figure 3. Sacramento River water temperature below Wilkins Slough June-July 2019. Note that water quality standard is 68oF, above which salmon become stressed.

Figure 4. Sacramento River fall-run salmon escapement 1952-2018.

Saving Killer Whales By Increasing Salmon Production

In a January 18, 2019 post, I related the state of Washington’s plan to increase the state’s hatchery salmon production to recover salmon populations and help the endangered southern population of killer whales.  In response to an executive order by the governor of Washington, the Washington Department of Fish and Wildlife’s proposed broad measures to increase the numbers of hatchery-raised salmon smolts released into killer whale migration areas that have minimal numbers of wild salmon.  The program would also enhance commercial and sport fisheries for salmon.  Much of the hatchery program would remain committed to recovery of threatened and endangered wild salmon stocks, which would also get a boost in essential habitat restoration.

The proposal in Washington state calls for an additional 30 million smolts for the Puget Sound estuaries (near Seattle) and an additional 20 million for the Columbia River estuaries, 50 and 20 percent increases, respectively.  The proposal recognizes:

 [H]atchery practices can pose serious genetic and ecological risks to wild populations if not managed carefully with full consideration of all that has been learned over the history of salmonid hatchery programs in the Pacific Northwest. However, the design of this proposal strives to minimize such negative impacts and to afford protection to the existing wild chinook populations to the greatest extent possible.

Elements of the program would include releasing hatchery smolts in lower river and estuary areas.  The program is designed to minimize effects on wild salmon by keeping these releases outside of the normal rearing and migration routes of wild salmon.  In some cases, hatchery salmon fry would be transported to net pens in lower rivers and estuaries for rearing and eventual release of smolts near the ocean, thereby further increasing smolt survival.  Returning adult salmon would home in on such sites, creating opportunities for terminal fisheries for hatchery salmon while retaining upriver spawning grounds for wild salmon.

A similar program is being planned and tested in California in the San Francisco Bay Estuary of the Sacramento and San Joaquin rivers.  Central Valley hatchery salmon smolts are already being trucked to the Bay and nearby coastal estuaries.  A new program element under consideration is the trucking of fry to local Bay estuary net pens for rearing.  If successful, this would create new terminal sport and commercial fisheries, while enhancing coastal fisheries and prey for the California Killer Whale populations.

One goal of the program in California would also be to shift hatchery salmon fisheries away from rearing areas and migration routes of wild salmon.  Rearing fry and releasing smolts in areas not frequented by wild salmon should reduce the effects of the hatchery program on wild salmon.  Similarly, terminal fisheries would focus harvest away from migration routes of wild salmon and reduce competition with wild salmon in spawning areas in upper rivers.  Commercial and sport fisheries would be enhanced along the coast.  New terminal fisheries would be created at estuary and coastal release sites that attract adults originally released at the sites as smolts.

If all goes well, such programs will benefit killer whales, sport and commercial fisheries, and wild salmon population (through reduced competition and better harvest management).

For more detail on Oregon and Washington Select Area Fisheries Enhancement programs see https://www.dfw.state.or.us/fish/OSCRP/CRM/reports/16_reports/2016%20_SAFE%20_Annual.pdf.

 

 

 

Delta Smelt – Spring 2019 Status

Late April and early May 20-mm Surveys provide an excellent picture of the status of Delta smelt population in the estuary. Since 2017, some surveys collected no Delta smelt (Figures 1-3) in the San Francisco Bay-Delta estuary. The 2018 and 2019 survey catches (Figures 1 and 2) are a new low for Delta smelt, lower even than the 2017 survey catch (Figure 3), and the lowest in the 1995-2019 survey period.

The outlook for the Delta smelt population remains grim after these lows. Despite good conditions in spring 2018 and 2019, the severely depressed number of adult spawners indicates a continuing weak potential for recovery.

Figure 1. Catch and lengths of Delta collected in the 20-mm Survey in spring 2019. None were collected in survey 3.

Figure 2. Catch and lengths of Delta collected in the 20-mm Survey in spring 2018. None were collected in surveys 4 and 5.

Figure 3. Catch and lengths of Delta smelt collected in the 20-mm Survey in spring 2017.

Napa River Smelt Sanctuary

The Napa River and its estuary are an important spawning and rearing area for longfin and Delta smelt, especially in wet years. Wet years, with their high Delta outflows (Figure 1) and modest Napa River flows (Figure 2) provide spawning habitat for the smelt in the Napa River and its estuary (Figures 3-6).

Wet year 2019 shows use by longfin (Figure 3), but little use by Delta smelt (Figure 7), which likely reflects their low population abundance.

Because the smelt populations have strongest recruitment in wet years,1 the Napa River estuary likely is an important contributor to their overall population health and abundance. The Napa River estuary deserves more attention in smelt recovery strategies. However, that should not take away from improving upper Bay-Delta estuary habitat conditions in all water year types.

Figure 1. Delta outflow in recent wet years 2011, 2017, and 2019.

Figure 2. Napa River flows 2009-2019.

Figure 3. 20-mm Survey results for Longfin smelt March 2019. Source

Figure 4. 20-mm Survey results for Longfin smelt March 2017.

Figure 5. 20-mm Survey results for Delta smelt April 2011.

Figure 6. 20-mm Survey results for Delta smelt April 2017.

Figure 7. 20-mm Survey results for Delta smelt April 2019.