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Climate Change, Delta, Fish Report

The San Joaquin River floods Newman, California in March 2011.

Water surged over roadways and spilled onto sidewalks along the coast last week as California witnessed a king tide event, or the highest (and lowest) tides of the year. These extreme tides happen when the moon and sun are closest to the earth and exert their greatest gravitational pull. While the king tide naturally occurs every year, it also provides a glimpse into the not-so-distant future, when rising sea levels turn such floods and surges into more frequent events. 

California’s sea level is expected to climb between 3 and 4.5 feet in the next 90 years from the expansion of warming ocean water and the melting of glaciers and ice sheets (Pacific Institute 2009). As the ocean creeps higher each year, the highest tides also reach farther onto shore. Many groups use the king tide event to raise awareness about sea level rise, since today’s extreme water levels will one day become commonplace. The California King Tide Initiative hosts a website where residents can share photos of the king tides in their communities. Such photos preview the conditions that lie ahead, offering a chance to reflect on needed preparations, and ways to slow the warming of our planet.

Rising sea levels won’t just inundate California’s coastline—they may splash the Central Valley as well. Higher tides can push all the way through to the Sacramento-San Joaquin River Delta, and pose just one of many threats to the Delta’s aging levee system. About two-thirds of the Delta sits below sea level—without the levees, it would be a huge, flooded marsh. Some 1,100 winding miles of levees keep the water at bay, many built more than a century ago. In 2006, California declared a State of Emergency for the levee system, and repairs to shore against earthquakes and flooding have been underway ever since. FISHBIO is currently helping to monitor how recent levee repairs affect salmonids and other fish species in the Sacramento River.

This post featured in our weekly e-newsletter, the Fish Report. You can subscribe to the Fish Report here.

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Delta, Fish Report

In this post-Katrina world, California is struggling to find a balance between the protection of its environment and its citizens. Much of the destruction and loss of life in New Orleans resulted from levee failure and subsequent flooding. In the wake of the devastation the U.S. Army Corps of Engineers (Corps) began a nation-wide evaluation of levee systems and many didn’t make the cut. In 2007, the Corps released a white paper announcing that they wanted the removal of a substantial amount of vegetation from the banks levees maintained by both federal and non-federal entities nation-wide to increase stability of the levee systems. The levee vegetation removal policy was in response to the Katrina disaster, however, before the Corps released the new policy, it was determined that levee failures that occurred during Katrina were a result of engineering and construction issues and not the vegetation. In response to the new national policy, the California Department of Fish & Game (CDFG) has filed suit against the Corps, stating that the policy does not comply with the federal Endangered Species Act, National Environmental Policy Act, and federal Administrative Procedure Act.

The national policy that the Corps adopted seems counterproductive to what they have been working towards in recent years in California. Since 2006, the Corps, CDFG, California Department of Water Resources, U.S. Fish & Wildlife Service, National Marine Fisheries Service and other agencies have been involved with the Sacramento River Bank Protection Interagency Working Group in an effort repair levees and increase habitat by planting a substantial amount of vegetation on the banks. The white paper lists reasons why vegetation can be destructive to levees including impeding access for maintenance and inspections, hindering emergency flood fighting operations and removing soil from the levee when uprooted by wind. However, CDFG states that the newly adopted policy disregards other national policies, and is a complete reversal of studies previously conducted by the Corps. CDFG argues that studies conducted by the Corps reveal that vegetation on levees can minimize the effects of flooding and in the past the Corps has encouraged (even in some cases required) the planting of trees and shrubs on California levees. The removal of riparian habitat would likely have detrimental effects on several endangered species including Chinook salmon, steelhead, valley elderberry longhorn beetle, riparian brush rabbit, western yellow-billed cuckoo and Swainson’s hawk. It is estimated that only five percent of the original riparian forests remain in the Central Valley and the new policy would reduce this further at a steep price of $7.5 billion. The Corps recognizes some of the beneficial elements of vegetation on levees, such as forming habitat for wildlife, decreasing surface erosion caused by rain, and creating visually appealing landscapes, but determined that the dangers are not worth the risk.

With a quickly growing population and considerable development within the floodplains, efforts to protect lives and property have sometimes caused destruction of habitat for endangered species in the Central Valley. In order for both society and the environment to benefit, the federal, state and local agencies need to work together to come to an agreement on the best approach to the levee system. Recently, the Corps declared 180 miles of levee systems in California ineligible for federal rehabilitation assistance if they are damaged during a flood due to a lack of detail in a new state and local levee maintenance plan along with inadequate inspections. Their intentions are good, but the conflict has only been worsening in recent weeks and there is no resolution in sight.

This post featured in our weekly e-newsletter, the Fish Report. You can subscribe to the Fish Report here.

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Conservation, Delta

freshwater asian clamAs flows receded in a Central Valley river, these Asian clams (Corbicula fluminea) became exposed along this gravel bar and were left to bake in the sun. The Asian clam is one of the most widespread non-native aquatic bivalve mollusks (e.g., “mussels” or “clams”) in North America. Non-native mollusks get a lot of attention because of there alien status, but native mollusks are largely underappreciated. In fact, North America has the greatest diversity of freshwater mussels in the world (approximately 290 species), but 72% are listed as recently extinct, endangered, threatened, or of special concern (Williams et al). Mussels are commonly considered biological monitors of water quality since they are sensitive to pollutants in rivers and lakes.

Perhaps the most interesting characteristic of freshwater mussels is their reliance on fish to complete their life-cycle. When adult mussels reproduce, the males release sperm into the water column and the females draw the sperm into their shell cavities to fertilize their eggs. The fertilized eggs develop into larvae, called glochidia, and then 75,000 to 3,000,000 glochidia per female are released into the water column. Once released, glochidia must attach to the gills or fins of an appropriate fish host to complete their metamorphosis into the juvenile stage. After anywhere between 1 to 25 weeks the juvenile mussel detaches from its host and falls to the substrate to complete its development into a sedentary, but free-living adult. Some mussel species may successfully use a variety of fish species, including salmonids, but the majority are thought to be host-specific. Without the right host fish mussels can’t complete their life cycle, therefore, they are dependent on the conservation of the host fish.

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Delta

There are numerous trawl surveys conducted through out the year in the San Francisco Bay-Delta to monitor species such as Delta smelt (Hypomesus transpacificus), longfin smelt (Spirinchus thaleichthys), striped bass (Morone saxatilis), American shad (Alosa sapidissima), splittail (Pogonichthys macrolepidotus), threadfin shad (Dorosoma petenense) and all races of Chinook salmon smolts (Oncorhynchus tshawytscha). Midwater trawling has been conducted by the U.S. Fish and Wildlife Service (USFWS) in the spring at Chipps Island since 1976 to monitor the outmigration of Chinook salmon. This survey is used to estimate the number of unmarked salmon emigrating from the Delta and to recover marked smolts released in mark and recapture survival experiments like VAMP. Midwater trawls utilize a single boat towing a net with a large opening 15ft. by 30ft. (4.6m by 9.1m) that reduces down to a cod end. The sampling consists of ten 20-minute trawls per day, three to seven days per week (seven days per week during coded wire tagged fish recovery periods).

A Kodiak trawl has been operated since 1988 in the lower San Joaquin River from Mossdale to the Head of Old River. Two boats are required to pull a 6ft. by 25ft. (1.8m by 7.6m) net into the flow. The ‘Mossdale Trawl’ is currently operated by California Department of Fish & Game (CDFG) during the spring, and USFWS the rest of the year. Sampling by CDFG normally occurs during a 10-week period beginning in April and extending through mid-June. Sampling consists of ten trawls daily for 20-minute intervals, three to seven days per week, depending on fish abundance. The purpose of this annual survey is to estimate the juvenile Chinook (smolt) outmigration from the San Joaquin River; evaluate temporal and spatial distributions; and examine the relationship between juvenile Chinook salmon abundance and environmental variables. As you can see from the graph above, peak catch of 2011 outmigrating Chinook salmon occurred in mid-June and migration was completed by the end of the month.

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Delta

The Sacramento-San Joaquin Delta is a complex system to navigate and structures like the Delta Cross Channel (DCC) gates can turn a navigable waterway into an unexpected dead end. The DCC was constructed in 1951 to divert water from the mainstem of the Sacramento River into the Mokelumne River and through the interior Delta. The United States Bureau of Reclamation (USBR) built the DCC as a response to saltwater intrusion into the Delta, which occurs when water is exported from the South Delta. The gates can be opened and closed depending on water quality, flood protection, and fish protection requirements.

There are many structures in the Delta and Suisun Marsh designed to control salinity and water quality levels. Salinity intrusion is a major concern for agricultural and municipal water users that draw water from the Delta. Water managers use the 2 practical salinity unit isohaline, better known as “X2”, for tracking the direction and magnitude of fluctuations in salinity. The X2 is tracked as the distance upstream from the Golden Gate and is maintained by releasing water from upstream reservoirs and adjusting export rates. The position of the X2 is legally established through the 2008 biological opinion (OCAP) and subsequent court decisions.

The Suisun Marsh Salinity Control Gates (SMSCG) are large, radial arm floodgates similar to the DCC, which restrict the flow of high salinity water from Grizzly Bay into Montezuma Slough and maintain lower salinity in the brackish marsh. Additionally, the California Department of Water Resources (DWR) annually installs three agricultural barriers and one fish barrier in the South Delta. The agricultural barriers in Old River, Middle River and Grant Line are rock barriers designed to increase water height, circulation, and quality. The Head of Old River Barrier (HORB) is a fish barrier designed to improve operational flexibility of the State Water Project and help reduce fishery impacts by preventing migrating fish from entering Old River. Before heading out to explore the California Delta it’s best to do your homework and check on the status of the delta structures to prevent running into a dead end.

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Delta

In his annual State of the State address, California Gov. Jerry Brown reiterated a desire to move forward with the Bay Delta Conservation Plan (BDCP) and have a proposal ready this summer outlining a project that is intended to restore the Delta ecosystem while still providing water to communities throughout the state (the co-equal goals of the BDCP). Of course, he is referring to the controversial peripheral canal project, which would divert water from the Sacramento River around the delta (or through, depending on the alternatives) and directly to the main aqueducts of California via the state and federal pumping stations.

The existing system draws water from the southwest section of the Delta, manipulating flow throughout the estuary. One study suggests that increasing exports likely increases the number of salmon from the Sacramento River that stray into the southern Delta and become entrained in the pumps (Newman and Brandes, 2009). Another study demonstrated that survival is lower for San Joaquin River salmon using the Old River route during outmigration (that leads towards the pumping stations), than for salmon migrating in the mainstem of the river (VAMP 2011). If the pumps entrain fish, they are salvaged and trucked to several release sites throughout the western Delta; however, not all entrained fish will survive the salvage process. The California Department of Fish and Game (CDFG) released the 2011 data showing that a record 11 million fish were salvaged while a record amount of water was drawn at the pumping stations. It is yet to be determined if the abundance of salvaged fish is a sign that the populations are rebounding or if the higher numbers are due to the record volume of pumped water, or most likely a combination of the two.

A total of $125 million has been spent since 2006 on the BDCP and Delta Habitat Conservation and Conveyance Plan (DHCCP) planning activities and another $115 million is expected to be spent through 2013. Estimates indicate that the peripheral canal could cost roughly $12 billion, but there is no way to truly know the price tag until a plan is drawn up and an environmental impact report is conducted.

One thing is certain, the Delta is a vulnerable ecosystem that is being pushed to its limits. If there is not a strategy to modify the way we utilize our resources or present ways that we can reduce the amount of resources used, then we will continue to struggle with prioritizing social matters and environmental concerns.

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Delta, Other Fish Species, Salmon

Last Wednesday the California Department of Fish and Game (DFG) hosted a public meeting in Rio Vista to unveil proposed changes to striped bass fishing regulations. The DFG is required to make changes to the regulations under a lawsuit settlement earlier this year. The meeting was heated and emotional at times with approximately 300 in attendance, representing sport fisherman throughout the state. Many expressed their concerns over the impacts the proposed regulation might have on the future of striped bass fishing in California.

The lawsuit by the Coalition for a Sustainable Delta against the DFG was settled in April 2011. Under the settlement, a comprehensive proposal to address striped bass predation in the Delta must be developed by state and federal fishery management agencies. As part of the settlement DFG must make appropriate changes to the bag limit and size limit regulations to reduce striped bass predation on the listed species, develop an adaptive management plan to research and monitor the overall effects on striped bass abundance, and create a $1 million research program focused on predation of protected species.

The striped bass regulations include raising the daily bag limit for striped bass from 2 to 6 fish with a possession limit of 12, and lowering the minimum size for striped bass from 18 to 12 inches. There will also be a “hot spot” for striped bass fishing at Clifton Court Forebay with a daily bag limit of 20 fish, a possession limit of 40 fish and no size limit. Fishing the hot spot will require a report card to be filled out and deposited it in an iron ranger or similar receptacle.

These proposed regulations are not designed to extirpate the striped bass population in California, but are expected to help reduce predation pressure by striped bass on native salmonids and Delta smelt. There are multiple factors, such as diversion facilities, loss of habitat, water quality and predation that have adverse effects on endangered fish in the Delta. In order to address recent declines in salmonid and Delta smelt populations various changes in management practices have been implemented. These practices include, the Biological Opinions on the long-term operations of the Central Valley Project and State Water Project, the Central Valley Project Improvement Act (CVPIA), Total Maximum Daily Load (TMDL) requirements and state and federal fishing regulations. The proposed striped bass reduction plan would join the line up of controversial policies aimed at minimizing the effects of these potential stressors.

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Delta, Field Crew, Salmon

hatchery fish juvenile chinookCalifornia’s three main state hatcheries (Nimbus-American River, Feather River, and Mokelumne River hatcheries) were constructed to mitigate for production of anadromous Chinook salmon lost as a result of dam construction, but a large majority of these fish never make it back to their natal stream. In an effort to increase survival, approximately 10-12 million state hatchery fish are trucked to the Bay-Delta each year, and in most years they are released into net pens where they are allowed to acclimate before being released into the Bay-Delta. Since some of the hatchery fish are coded-wire tagged (CWT) prior to release, data can be collected on these fish once they are harvested or when their carcasses are recovered after spawning. 

A review of the CWT data collected from fish released from the Mokelumne River Fish Facility (MRFF) indicates that hatchery fish released into the Bay-Delta contribute a greater proportion to the ocean fisheries compared with those released in river, but contribute proportionally less to escapement in the Mokelumne River compared with fish released into the river (Smith and Workman 2004). Part of the reason for this discrepancy is that the salmon released in the Bay-Delta that do return to spawn are known to have a high rate of straying (e.g. they return to rivers other than their river of origin), which is presumed to be because fish that are trucked to the bay are not given the opportunity to properly imprint on their natal stream. It is believed the straying rate of the fish released in the Bay-Delta could exceed 70% (California Department of Fish and Game and National Marine Fisheries Service 2001).

Unlike the state hatcheries, Coleman National Fish Hatchery (CNFH), a federal hatchery operated by U.S. Fish & Wildlife, releases most of their production directly into the river near the hatchery. Studies indicate straying is fairly low when hatchery fish are released into the river and rates are generally less than 10%. On a few occasions, when CNFH released fish into the Bay-Delta (e.g. 1989-1991 because of drought conditions in-river and 2008 to supplement Bay-Delta releases following a drastic decline in salmon) straying was extremely high (75.3%) and comparable to the state hatcheries.

There is a trade-off that California hatcheries make between survival to the ocean and straying of escapement. Data analysis suggests releases in the Bay-Delta result in higher ocean contribution rates and likely higher overall survival than upstream releases. However, as a consequence a high percentage of fish that were released in the Bay-Delta stray and spawn in other rivers, complicating restoration of specific runs and reducing the genetic and life history diversity.

 

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Delta

duck weed on pondWhat looks like a pond creature from a late-night Sci-Fi movie is actually millions of tiny floating plants. Aquatic plants that are able to cover an entire water body in a very short period of time are usually thought of as invasive, nuisance species like water hyacinth, but that is not always the case. Duckweeds (Lemna sp.), native to the Western U.S., are some of the smallest flowering plants in the world, but can have an impressive impact. They rapidly multiply, doubling their mass in as little as two days, forming solid mats across a water surface. 

Although duckweeds generally don’t negatively impact water quality, they can foul up water diversion screens. These tiny aquatic plants can be quite useful as well. They have been shown to lower water temperature in ponds and slow moving waterways, and reduce evaporation rates by blocking out sunlight. Because of their rapid growth rate and ability to absorb nutrients such as ammonia, nitrates, phosphorous, and potassium, duckweed has been used in the treatment of effluent in wastewater treatments facilities (Ran, N. 2004). Under certain conditions, duckweed has the ability to absorb heavy metals, and can be used as an indicator of pollution or excess nutrients in water bodies (Nasu Y., and M. Kugimoto 1981).

In Southeast Asia, duckweed is harvested and fed to livestock to provide a good source of protein and minerals. Duckweed has even shown potential as a source of organic biomass for the production of ethanol (Kesaano M. 2011). Perhaps someday duckweed can be utilized to treat our sewage, then used to produce ethanol to fuel our cars… talk about recycling!

 

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Delta

central-velley-delta

Last week FISHBIO attended the Delta Multiple Stressors Workshop in Sacramento, CA. The workshop was held by the Delta Independent Science Board in response to requests by members of the California Senate and Assembly for a list and assessment of Delta stressors. At first glance creating a list of “stressors” may not seem difficult, but it quickly became apparent that this was not the case. While every researcher, law maker and citizen of Northern California has an opinion on what the main “stressors” are to the health of the Delta ecosystem and the reliability of the water supply (the co-equal goals of Delta Stewardship Council), the catch is listing them in an appropriate manner. First, it became clear that even among Delta researchers there is confusion over whether the terms “stressor”, “threat”, “pressure” and “driver” are analogous or interrelated. Secondly, it was evident that the appeal came from a the lawmakers’ desire to rank the stressors by importance. However, to rank something by importance you need a clear idea of the purpose of the ranking – is it ecosystem triage? Water distribution? Cost allocation? Much of the day was spent in a long discussion of how to categorize stressors, criteria for a potential ranking system, and the general merits of ranking stressors.

Another issue is that by simply listing stressors, it appears that ‘all stressors are created equal’, when this is clearly not the case. Stressors vary over time and space; dredging has relatively short term and localized effects, while sea level rise will have long term effects on the entire system. Thus, in order to make the list meaningful, you need to connect stressors and measurable goals to the appropriate spatial and temporal scale. Suddenly, the list is beginning to look like an Amtrak timetable.

Last, but definitely not the least of the ISB’s concerns is that many of these stressors are related and cannot be treated or assessed separately. For example, the average salinity in the Delta has changed over time due to the decline in Delta outflows, and the food web has changed due to the introduction of non-native species. How do you describe these relationships on paper? There were various examples shown of complex flow charts that make your head spin, which one researcher referred to as a plate of ‘spaghetti and meatballs’ (big circle text boxes linked by squiggly lines). It seems that the ISB’s task for the next few weeks will be to merge the ‘Amtrak timetable’ with the ‘spaghetti and meatballs’ into something comprehensible for the Senate, Assembly and general public. As one Delta researcher put it, no matter what you call them, these “stressors” are really stressing people out.

The memo is slated for release to the public January 27th.

Photo source: FISHBIO