Do largemouth bass like droughts?

By Andrew L. Rypel

“The Delta is full of species that thrive in the lakes in southern Arkansas” ~Bill Bennett

Aerial photo of Lake Lanier, GA during the 2007 drought. Photo source:

by Andrew Rypel

As we rapidly enter another drought, long-standing questions on ecological impacts of increased temperatures, reduced water levels and flows re-emerge. This reality recently reminded me of some of my own previous work looking at growth rate variations of largemouth bass in response to droughts in the southeastern USA (Rypel et al. 2009). Results from this work may be useful/interesting for biologists and managers in California considering similar questions.

While droughts elsewhere occur, they do so on different time tables and climatic cycles than in CA. Yet many of the species and underlying ecological dynamics remain similar (Marchetti et al. 2001, Scott and Helfman 2001, Rahel 2002, Moyle & Mount 2007). The homogenization of ecological communities on Earth is one of our greatest challenges, and parallels human modifications to landscapes, cities and food systems. For example, when traveling to far flung destinations, one could with little effort, eat at all the same restaurants, shop at the same stores, and access almost the exact same products. Similarly, most aquatic systems with suitable temperatures and fish habitat across North America (and other continents!) contain species like bluegill, largemouth bass, common carp and so on. Today, we’ll focus on largemouth bass, a species common throughout California. Indeed it is important to remind ourselves that California shares a non-native fish fauna with other states, that we can learn from, and that warm-water fishes are expanding in CA. California is home to some of the largest black bass captured on Earth, and there is some evidence that they compete with and prey on our rapidly declining native fishes. So, they’re definitely worth thinking about.

(Top) A fisher with a 16 lb largemouth bass captured in Telfair County, GA. Source (Bottom) Example of an uncut and sectioned largemouth bass otolith. In this case, eight annular rings were exposed. Photo source:

During the mid-2000s, I was assisting the Georgia Department of Natural Resources by researching largemouth bass populations from some of their reservoirs. Biologists had been extracting otoliths from bass populations to calculate and study the usual metrics: growth mortality, age class diversity and reproductive success. Otoliths are calcified bony structures in the inner ear of fishes. They provide fishes a sense of equilibrium in the water, and lay down concentric rings, much like tree-rings. I had similar samples from ecosystems in Alabama and Mississippi.

Bass fisheries are the primary focus for many fisheries managers in the southeast, and generate extraordinary economic impact locally (Chen et al. 2003). Bass fisheries are also important in California, but receive somewhat less adulation than in southeast.

During this work (circa 2006-2008), a historic drought struck the region, and reservoir levels plunged. This quickly led to concern among anglers and the public over what might be happening with fish populations. Coincidentally, I was also exploring dendrochronology (tree-ring) techniques applied to fish otoliths, and the idea was hatched to measure incremental growth of each fish in all of its years of life. Using this approach, we might better understand conditions when bass growth well or poorly, including how bass responded to drought, specifically.

I examined 397 bass otoliths from 13 waterbodies across Georgia, Alabama and Mississippi. Using the annual increments led to a much larger sample of 1450 annular growth increments. Each growth history for each fish was detrended to remove growth trends related to fish growing more when they are younger and less when older. Interseries correlations were high, ranging 0.27-0.88, with a mean of 0.62. This result indicated that, within populations, individual bass growth was highly synchronous over time among individuals. It was also immediately clear that the years 2000 and 2007 (two major drought years) were “pointer years” – with exceptionally high growth across populations. In contrast, 1994, 1997, and 2003 were usually poor years of growth.

Examples of nonage-related variation in annual growth of bass across reservoirs . High growth ‘pointer years’ were usually observed during drought years.

When growth rates were correlated with various climate indices, the pattern became clear: Bass growth tended to increase with temperature and decrease with precipitation. Droughts appeared to be good for bass. In fact, the pattern was so strong that ~50% of bass growth in any ecosystem could be predicted based solely on climate variables. I found this statistic to be astounding, especially given that density-dependent effects (e.g., growing less when population sizes are large) in bass populations can be quite strong. However, a related study clearly indicated that lipid (fat)  deposits in seven warmwater species and thousands of fish in an Alabama Reservoir spiked up to 5x during the 2000 drought (Rypel and Bayne 2009).

There are a few potential explanations for the pattern. Most importantly, largemouth bass are a warmwater fish species. As such, their metabolism and vital rates increase directly as a function of temperature, up to some very high thresholds (Glover et al. 2012), especially compared to California’s cold-adapted native fish fauna (Jobling 1981, Zillig et al. 2021). Second, reduced water levels may concentrate prey like sunfishes and shad (Schlosser 1985, Craven et al. 2010). Finally, reduced water levels may also stimulate nutrient cycling and primary production. For example, large algal blooms are often observed in reservoirs during unusually hot and dry summers (Braga et al. 2015), which can temporarily boost food availability for small fish.

So unfortunately, increased temperatures and droughts are likely boons for non-native warmwater non-native species like largemouth bass. It is worth noting that this study was done on the other side of the country; thus we don’t know if these results translate to the arid West and California. However, black basses have been on the march for some time (Rypel et al 2017). In the upper midwest, largemouth bass populations have increased dramatically, while populations of native cool- and cold-water fishes like Walleye and Cisco have declined (Sharma et al. 2011, Rypel et al. 2018).  There is no reason these patterns should be different in California ecosystems. Indeed they may even be more pronounced because the benefits to basses during droughts will likely assist non-native populations further expand their footprint. A statewide assessment of climate change effects on native and non-native fishes indicates that warmwater fishes such as largemouth bass will benefit from increased temperatures and lower reservoirs, while most native fishes will have their declines hastened (Moyle et al. 2013).

The future is now, and it looks like it is going to involve large and fast-growing black bass populations.

A view of Lake Shasta from 3/21/201. Photo by Amy Holland/USBR. Source:

Further Reading

Braga, G. G., V. Becker, J. N. P. d. Oliveira, J. R. d. Mendonça Junior, A. F. d. M. Bezerra, L. M. Torres, Â. M. F. Galvão, and A. Mattos. 2015. Influence of extended drought on water quality in tropical reservoirs in a semiarid region. Acta Limnologica Brasiliensia 27(1):15-23.

Chen, R., K. Hunt, and R. Ditton. 2003. Estimating the economic impacts of a trophy largemouth bass fishery: issues and applications. North American Journal of Fisheries Management 23(3):835-844.

Craven, S. W., J. T. Peterson, M. C. Freeman, T. J. Kwak, and E. Irwin. 2010. Modeling the relations between flow regime components, species traits, and spawning success of fishes in warmwater streams. Environmental Management 46(2):181-194.

Gaeta, J. W., G. G. Sass, and S. R. Carpenter. 2014. Drought-driven lake level decline: effects on coarse woody habitat and fishes. Canadian Journal of Fisheries and Aquatic Sciences 71(2):315-325.

Glover, D. C., D. R. DeVries, and R. A. Wright. 2012. Effects of temperature, salinity and body size on routine metabolism of coastal largemouth bass Micropterus salmoides. Journal of Fish Biology 81(5):1463-1478.

Jobling, M. 1981. Temperature tolerance and the final preferendum—rapid methods for the assessment of optimum growth temperatures. Journal of Fish Biology 19(4):439-455.

Marchetti, M. P., T. Light, J. Feliciano, T. Armstrong, Z. Hogan, and P. B. Moyle.  2001.  Homogenization of California’s fish fauna through abiotic change.  Pages 269-288 in J.L. Lockwood and M.L. McKinney, editors.  Biotic Homogenization.  Kluwer/Academic Press, New York.

Moyle, P.B. and J. Mount. 2007. Homogenous rivers, homogenous faunas. Proceedings of the National Academy of Sciences 104: 5711-5712.  

Moyle, P.B., J. D. Kiernan, P. K. Crain, and R. M. Quiñones. 2013. Climate change vulnerability of native and alien freshwater fishes of California: a systematic assessment approach. PLoS ONE 8(5): e63883.

Rahel, F. J. 2002. Homogenization of freshwater faunas. Annual Review of Ecology and Systematics 33(1):291-315.

Rypel, A. L. 2009. Climate–growth relationships for largemouth bass (Micropterus salmoides) across three southeastern USA states. Ecology of Freshwater Fish 18(4):620-628.

Rypel, A. L., and D. R. Bayne. 2009. Hydrologic habitat preferences of select southeastern USA fishes resilient to river ecosystem fragmentation. Ecohydrology 2(4):419-427.

Rypel, A. L., D. Goto, G. G. Sass, and M. J. Vander Zanden. 2018. Eroding productivity of walleye populations in northern Wisconsin lakes. Canadian Journal of Fisheries and Aquatic Sciences 75(12):2291-2301.

Rypel, A. L., J. Lyons, J. D. T. Griffin, and T. D. Simonson. 2016. Seventy-year retrospective on size-structure changes in the recreational fisheries of Wisconsin. Fisheries 41(5):230-243.

Schlosser, I. J. 1985. Flow regime, juvenile abundance, and the assemblage structure of stream fishes. Ecology 66(5):1484-1490.

Scott, M. C., and G. S. Helfman. 2001. Native invasions, homogenization, and the mismeasure of integrity of fish assemblages. Fisheries 26(11):6-15.

Sharma, S., M. J. Vander Zanden, J. J. Magnuson, and J. Lyons. 2011. Comparing climate change and species invasions as drivers of coldwater fish population extirpations. Plos One 6(8):e22906.

Zillig, K. W., R. A. Lusardi, P. B. Moyle, and N. A. Fangue. 2021. One size does not fit all: variation in thermal eco-physiology among Pacific salmonids. Reviews in Fish Biology and Fisheries 31:95-114.

Andrew Rypel is a professor of Wildlife, Fish, and Conservation Biology and Co-Director of the Center for Watershed Sciences at the University of California, Davis.

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How dry is California? What should we prepare for?

by Jay Lund

California is in the second year of a drought. Governor Newsom this week made his first drought declaration.  

Just how dry is this drought, so far?  What are some likely implications?  And what might State and local governments do about it?

How dry is it? 

California Data Exchange Center has some excellent collections of water data:

Precipitation – Northern California has received about 48% of average historical precipitation for this time of year.  This is the 3rd driest water year on record, so far.  Only 1924 and 1977 were drier in precipitation over the last 101 years.  At this time of year, there will probably be little more precipitation until fall.

Snowpack – Statewide snowpack is about 30% of average for this date.  Snowmelt will only help reservoir storage a little this year, but we will be glad to get any of it.

Temperatures – Temperatures have been warmer than historically, and we should watch how they develop over the year.  In the 2012-2016 drought, warmer temperatures increased evaporation and dried soils much more quickly, further reducing streamflows, groundwater recharge, and stressing already-dry forests and aquatic ecosystems.

Surface water runoff – With warmer temperatures, this year might develop to rank drier in streamflow than precipitation, but it is too early to tell yet.  Historically, precipitation this low would lead to Sacramento Valley annual streamflow of about 5-6 million acre-ft, compared to an average of about 18 million acre-ft., more than 2/3 loss of average surface water available. 

Reservoir storage – Statewide, reservoirs are at about 74% of their long-term average.  Last year was dry, and this year’s runoff hasn’t helped.  The table below shows the major Sacramento Valley reservoirs are all quite low.  Shasta, Oroville, Folsom, and New Bullards Bar are all lower today than they were on this date in any year of the 2012-2016 drought.  This is especially concerning remembering that in both 2014 and 2015, Shasta ran out of cold water early, killing about 95% winter run juveniles, in 2014 suburban water utilities were quite worried for their Folsom supplies, and in 2015 levels were low enough to build a salinity barrier in the Delta.  This drought seems to be off to a faster start than the 2012-2016 drought.

Figure 1. Some major current reservoir levels today and over the last few years, including the 2012-2016 drought (US Army Corps of Engineers)

The Colorado River’s huge reservoirs are very low, 56% of average storage (only 41% of capacity). Colorado River drought plans are being triggered.

What are some likely implications? 

The drought could end quickly, or it could go on for several more years.  We will all hear informed (and uninformed) speculation on this.  The informed speculation will be interesting, but perhaps not useful (such as the great El Nino distraction of the previous drought).

Cities seem mostly well prepared for this drought with stored surface and groundwater, and water banking and purchase agreements with farmers. They have continued drought preparation and water conservation efforts since the last drought.  Conditions for cities might worsen with additional dry years, so more water purchases might be negotiated, given the surplus water conveyance capacities available this year.  There will likely to be calls for more water conservation, mostly to help save water for potential additional dry years and to make some water available for other uses.  Urban water use is only 20% of all water diversions, so conservation mostly tends to help cities bank water for later, but isn’t bad for others either.

Agriculture is a much greater water user and has less banked water, but still has access to considerable groundwater, which compensated for about 70% of lost irrigation water in the previous drought.  Water markets and selective fallowing will further reduce the economic impacts of remaining agricultural shortages, as they did in the previous drought.  Some farmers surprised by shortages in the 2012-2016 drought should be better prepared for this one, so far.  Droughts these days are tougher on agriculture than cities, given their relative water demands and greater difficulties preparing irrigated agriculture for drought, especially with the growing share of more profitable, but hard-to-fallow, permanent crops. Farm worker unemployment is likely in regions with more fallowing.

Groundwater always becomes a problem during drought, with less surface water inflows and much more pumping, mostly for agriculture.  Users of shallower rural wells suffer most directly from this.  This drought will make implementing the State’s Sustainable Groundwater Management Act (SGMA) for ending groundwater overdraft much more difficult, but also provide opportunities for local Groundwater Sustainability Agencies and state regulatory agencies (DWR and SWRCB) to provide more forceful and specific guidance and motivations for implementing practical and effective local groundwater management (meaning more pumping cut-backs and less delusional recharge estimates).

Rural drinking water supplies always worsen with drought.  This process will continue in every drought until SGMA is well-implemented and better support exists for rural water systems.  A few rural water systems have been connected to more secure supplies since the last drought and quite a few deeper wells have been drilled. But we should expect to hear of rural community and household water supplies becoming scarce or dry – hopefully fewer than before.

The Delta is always dicey in drought.  Lower freshwater flows greatly reduce water availability for exports and reduce water quality in various ways (not just salinity).  These conditions are worse for native species and better for invasive species.  It seems hard to predict exactly what will happen in the Delta’s ecosystem with drought, but it is usually not good.  Although sometimes less bad than predicted, each drought seems to bring a step decline in native fishes which does not recover after the drought. 

With such low reservoir levels, calls to reduce freshwater and environmental outflows from the Delta seem likely (rhetorical outrage machines will run overtime again.)  Any reductions in Delta environmental outflows should probably be stored (not exported), to support environmental flows in future drought years if needed.  And at the end of the drought, any remaining stored environmental water in reservoirs should be sold if it results in earlier resumption or increases in Delta exports – this has not been the case in previous droughts.  Ecosystems should see some benefits from any necessary drought reductions in outflow that benefit other water users (Lund and Moyle 2015). 

Ecosystems have the greatest difficulty preparing for drought, so they are the most vulnerable.  We are the least organized to prepare ecosystems for drought, manage them in drought, and recover them after drought.  In California’s highly variable climate, no wonder our ecosystems are declining.

Forest ecosystems will be stressed by drier and warmer-drier conditions, leading to greater spread of tree diseases and insect infestations.  The previous drought killed over 100 million trees in California and increased catastrophic wildfires for several years after the drought, with wildfire damages and loss of life far greater than all traditional drought damages combined.

Native fish populations always seem to decline during drought, and fewer recover after the drought.  This drought ratcheting effect on aquatic ecosystems has been part of this ecosystem’s ongoing declines. 

Waterbirds need wetlands, which become scarcer during drought.  Fortunately, waterbirds need less water than fish, and California’s system of national, state, NGO, and private refuges, duck clubs, and rice farming has become well organized over decades to support the Pacific Flyway.  In recent droughts, these groups have collaborated, planned, and managed wetlands for migratory waterbirds quite effectively.  They show what can be done when environmental interests are effectively organized and funded.

Should the Governor have already declared a statewide drought?

The Governor declared drought emergency conditions in two counties clearly hard hit by this drought and where an emergency declaration will facilitate tangible and effective state and local actions to reduce drought impacts.  The Governor’s statement also moves forward a range of activities that prepare for additional State drought actions regionally and statewide, without yet making a statewide drought emergency declaration. 

Droughts are long disasters, and they are mismanaged by both panic and complacency.  The current measured incremental approach seems wise.  It makes clear that State government is neither complacent nor panicked, and allows limited state agency resources to focus on and emphasize particularly urgent problems early while foreshadowing that other actions are being prepared, and that others should help prepare as well.   It allows public and media attention to grow as drought conditions and needs worsen, and allows this attention to adapt as the situation evolves.  If drought conditions become truly dire and widespread, draconian changes in public behavior will be needed.  And to get such a public response, it will be necessary to maintain (and in these times build) public trust in water management institutions by acting in measured ways.

We all should prepare for a dry time, and for the likelihood of drier times.  This could be a long haul, prepare earnestly, and don’t get exhausted too soon.  And prepare to make one outcome of this drought be better preparation for the next drought.

Further reading

Durand JR, Bombardelli F, Fleenor WE, Henneberry Y, Herman J, Jeffres C, Leinfelder–Miles M, Lund JR, Lusardi R, Manfree AD, et al. 2020. Drought and the Sacramento-San Joaquin Delta, 2012–2016: Environmental Review and Lessons. San Franc Estuary Watershed Sci. 18(2). doi:10.15447/sfews.2020v18iss2art2.

Lund, J., A.L. Rypel, and J. Medellin-Azuara (2021), California’s New Drought,, March 14, 2021.

Lund J, Medellin-Azuara J, Durand J, Stone K. 2018. Lessons from California’s 2012–2016 Drought. J Water Resour Plan Manag. 144(10):04018067. doi:10.1061/(ASCE)WR.1943-5452.0000984.

Lund J and PB Moyle, Water giveaways during a drought invite conflict,, March 23, 2015.

Stone, K. and R. Gailey (2019),Economic Tradeoffs in Groundwater Management During Drought,”, June 10, 2019.

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Suisun Marsh fishes in 2020: Persistence during the Pandemic

by Teejay O’Rear, John Durand, Peter Moyle

Two fishes that rely on Suisun Marsh for persistence in the San Francisco Estuary: striped bass and Sacramento splittail

Suisun Marsh is central to the health of the San Francisco Estuary. Not only is it a huge (470 km2) tidal marsh in the center the northern estuary (Figure 1), but it is an extremely important nursery area for species such as splittail, striped bass, longfin smelt, and, formerly, delta smelt. Since January 1980, a team from The University of California, Davis, in partnership with the California Department of Water Resources (DWR), has systematically monitored the marsh’s fish populations. The team had been sampling the fish and invertebrates every month with trawls and beach seines, with a nearly unbroken record. Then Covid-19 restrictions settled in, making it hard to continue sampling with a crew of four people in a 19-ft boat. How does one maintain a six-foot distance and still operate the boat and sampling nets? After a two-month hiatus in sampling, a solution was found: do the sampling with just two experienced people. The two-person crew was led each month by Teejay O’Rear, the highly experienced field manager of the Suisun Marsh project. Sampling took three exhausting days, but the data stream continued its flow. The following is a brief summary of what they learned about the marsh in 2020.

Figure 1. Suisun Marsh study area (“GYSO” = Goodyear Slough Outfall, “MIDS” = Morrow Island Distribution System, “RRDS” = Roaring River Distribution System, “SMSCG” = Suisun Marsh Salinity Control Gates, and “WWTP” = the Fairfield-Suisun Sanitation District’s wastewater treatment plant discharge point into Boynton Slough; map by Amber Manfree).

After the wet year of 2019, Suisun Marsh was subjected to very dry conditions in 2020. Delta outflow was lower than average throughout the year (and accompanied by little floodplain inundation), resulting in higher-than-average salinities. Two increasingly common conditions recurred in 2020: water was warmer than average (Figure 2), and clearer than average in summer and autumn.

Figure 2. Monthly average water temperature in Suisun Marsh in 2020 and for all years of the study (1980 – 2020); error bars are standard deviations in 2020 (* = no samples). See O’Rear et al. 2021 for details.

Fish catches in Suisun Marsh in 2020 reinforced three common observations: (1) lower flows and higher salinities are unfavorable for many common marsh fishes, whether native or non-native; (2) small, dead-end sloughs are key for supporting abundant fish populations; and (3) Suisun Marsh is disproportionately valuable to fishes of conservation importance. Nearly all fish species, both native and non-native, were less abundant than usual in 2020, especially those needing fresh water to spawn (Figure 3). In particular, the native, floodplain-spawning Sacramento splittail and non-native fishes that eat zooplankton and spawn in fresh water [threadfin shad, American shad, and striped bass] had reduced numbers. However, their numbers were relatively higher in Suisun Marsh than in the rest of the estuary. The frequently high numbers of all four species in Suisun Marsh since the early 2000s are notable given they are coincident with estuary-wide declines in plankton productivity and chronically low abundnaces of pelagic fishes in the estuary’s main rivers and bays (the “Pelagic Organism Decline”; Sommer et al. 2007). Many age-0 longfin smelt, a native zooplankton-eating species, were caught in Suisun Marsh in spring, which had not happened since 2013. Large fish catches most frequently occurred in small, dead-end sloughs where plankton concentrations are usually higher. Overall, Suisun Marsh is crucial for sustaining populations of valuable fishes, both native and non-native, particularly zooplanktivorous fishes and Sacramento splittail. The general pattern of native and non-native fish species responding in similar ways to environmental change suggests development of a novel ecosystem composed of species from all over the world (Figure 3; Aguilar-Medrano et al. 2019).

Figure 3. Annual average catch per trawl of native and non-native species in Suisun Marsh, 1980-2020.

We conclude with a discussion of two fish species that seem especially dependent on conditions in Suisun Marsh: Sacramento splittail and juvenile striped bass. 

Sacramento Splittail

Figure 4. Annual catches per trawl of three ages classes of Sacramento splittail in Suisun Marsh, 1980-2020. 

The splittail is a native minnow that spawns in areas that flood during winter months, especially the Yolo Bypass and Cosumnes River. Juveniles rear on flooded vegetation but emigrate en masse as water levels drop and move down the Sacramento River. Many, if not most, juveniles wind up in Suisun Marsh, when they are 40-50 mm long. They rear in the marsh for 2-3 years, until maturity, and then migrate with older fish to the spawning areas. They are repeat spawners, living 7-9 years. While splittail presumably once spawned and reared in many places in the rivers and estuary, today most of the population appears to spawn in the bypass and rear in Suisun Marsh, making them highly vulnerable to environmental change.

In the marsh, splittail numbers dropped considerably from 2019 to 2020, reflecting limited flooding. Nevertheless, catches were above average for the 40-year sampling period (Figure 4), reflecting in part a healthy adult population and quality rearing conditions in smaller sloughs for juveniles that did make it to the marsh. Extended drought may change this picture.

Striped Bass

Figure 5. Annual catch per trawl (purple squares) and catch per beach seine haul (red triangles) of striped bass. Most of the catch is young-of-year (age 0) bass. Figure from O’Rear et al. (2021).

Striped bass are not native but are one of the best indicators of ecological conditions because they complete their entire life history in the estuary watershed: they need healthy rivers, a healthy estuary, and a healthy coastal ocean to flourish. In our samples, striped bass catches consist mainly of young-of-year (age 0) individuals, but abundances plummeted in 2020 and were below average compared to all other years (Figure 5). Juvenile striped bass were most abundant in small sloughs, where planktonic food (i.e., opossum shrimp) was most abundant. The distribution and relatively low numbers of age-0 striped bass in 2020 was consistent with low flows in rivers supporting little successful spawning by adult bass and high zooplankton food in small, dead-end sloughs.


Sampling in Suisun Marsh has been the responsibility of many graduate students and others over the years, including Donald Baltz, Robert Daniels, Bruce Herbold, Lesa Meng, Scott Matern, Robert Schroeter, Patrick Crain, Alpa Wintzer, Sabra Purdy, and Brian Williamson. They have been assisted by literally hundreds of volunteers and student assistants. Huge thanks to Jacob Katz and Jacob Montgomery for their support in the tough year of 2020. We appreciate the continued support of the sampling program over the years by DWR. Randall Brown of DWR kept the program going during its early uncertain years. The views expressed in this report are those of the authors and do not reflect the official policy or position of DWR.

Further Reading

Aguilar-Medrano, R., J. R. Durand, V.H. Cruz-Escalona and P.B. Moyle. 2019. Fish functional groups in the San Francisco Estuary: understanding new fish assemblages in a highly altered estuarine ecosystem. Estuarine, Coastal and Shelf Science

Aha, N.M., P.B. Moyle, N.A. Fangue, A.L. Rypel, and J. R. Durand. 2021. Managed wetlands can benefit juvenile salmon in a tidal marsh. Estuaries and Coasts

Colombano, D.D., T.B. Handley, T. O’Rear, J.R. Durand, and P.B. Moyle 2021. Complex tidal marsh dynamics structure fish foraging patterns iin the San Francisco Estuary. Estuaries and Coasts. 

Colombano, D. D., J.M.Donovan, D.E. Ayers, T.A.O’Rear, and P.B. Moyle. 2020. Tidal effects on marsh habitat use by three fishes in the San Francisco Estuary. Environmental Biology of Fishes.

Colombano, D. D., A.D. Manfree, T. A. O’Rear, J.R. Durand, and P.B. Moyle. 2020. Estuarine-terrestrial habitat gradients enhance nursery function for resident and transient fishes in the San Francisco Estuary. Marine Ecology Progress Series 637: 141-157.

Moyle, P.B., A. D. Manfree, and P. L. Fiedler. 2014. Suisun Marsh: Ecological History and Possible Futures. Berkeley: University of California Press

O’Rear, T. A., J. Montgomery, P. B. Moyle, and J. R. Durand. 2021 (in review). Trends in Fish and Invertebrate Populations of Suisun Marsh, January 2020 – December 2020. Annual Report for the California Department of Water Resources Sacramento, California.

Sommer, T., C. Armor, R. Baxter, R. Breuer, L. Brown, M. Chotkowski, S. Culberson, F. Feyrer, M. Gingras, B. Herbold, W. Kimmerer, A. Mueller-Solger, and K. Souza. 2007. The collapse of pelagic fishes in the Upper San Francisco Estuary. Fisheries 32: 270-277.

Young, M., E. Howe, T. O’Rear, K. Berridge, and P. Moyle. 2020. Food web fuel differs across habitats and seasons of a tidal freshwater estuary. Estuaries and Coasts.

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Increasing groundwater salinity changes water and crop management over long timescales

by Yiqing “Gracie” Yao and Jay Lund

Salinity has often become a major limit for irrigated agriculture in semi-arid regions, from ancient Mesopotamia to parts of California today. A previous blog post showed that conjunctive use with more saline groundwater can differ fundamentally from freshwater aquifers. Higher salinity limits groundwater use for irrigation during dry years, when less surface water is available to dilute groundwater salinity, and increases aquifer pumping in wetter years to avoid water-logging. Brackish groundwater can no longer serves as drought storage, but becomes a supplemental water supply in all years, limited by availability of fresh surface water for diluting salts. This greatly reduces groundwater’s ability to support permanent crops and increases variability in annual crop acreage across different water years, thus reducing profit.

This post extends the analysis timescale of groundwater management with salinity to a century, examining groundwater storage management and cropping patterns as salts accumulate in an undrained aquifer. This discussion is based on results from a recent hydro-economic optimization model (Yao 2020), which conjunctively manages surface water and groundwater for irrigating a mix of annual and permanent crops over a range of dry to wet years to maximize agricultural profits. The modeling examined conditions similar to California’s western San Joaquin Valley.

The biggest change in long-term groundwater management with salinity is that more net recharge of groundwater storage and less overall pumping occurs in early decades to slow the rise in groundwater salinity. This prolongs the use of groundwater to supply some irrigation water (when diluted with available surface water), particularly for more profitable perennial crops.

With low initial groundwater salinity, greater early pumping lowers groundwater storage to a minimum allowable level, raising early profits, and groundwater recharge occurs in the last decades to recover aquifer levels (when recharge cost is most discounted). With modest groundwater salinity, costly artificial recharge occurs in early decades (Figure 1.a) when initial groundwater storage is low, to achieve the final storage target and slow accumulation of salinity to prolong the viability of more profitable perennial crops. With higher initial groundwater storage, aquifer levels are only lowered to the storage target towards the end (Figure 1.b) for the same reason.

Figure 1. Groundwater management strategy changes greatly with modest salinity (  = 500 mg/L) with a discount rate of 3.5% and final storage target of 10 MAF.

When initial groundwater salinity is high enough to reduce perennial crop yields, groundwater recharge is increased and occurs earlier to slow groundwater salination (Figure 1.a). Net extraction moves to the last decades if initial groundwater storage is high (Figure 1.b), which means profit from pumping in the first decades cannot offset losses in later decades from groundwater salinity accumulating from early pumping.

From an earlier blog post on conjunctive use without groundwater salinity, high initial planting costs and profits for perennial crops lead to maintaining perennial crop acreages as high as possible to reduce planting costs in later decades. However, in an undrained basin, as groundwater salinity grows, perennial crop acreage must shrink, driven by low fresh surface water availability in dry years to dilute more saline groundwater. However, the high value of salt-sensitive perennial crops drives the model to suppress growth in groundwater salinity in early stages to prolong crop yields.

The cost of groundwater salinity becomes huge. When groundwater salinity becomes high enough, it is no longer suitable for irrigation and must be disposed of to avoid water-logging. In our modeling, restoring the aquifer with fresher surface water never makes more profit than managing the salinated aquifer at a near-constant level and pumping away excess drainage. However, slowing the increase in groundwater salinity occurs in early decades when benefits of larger early less-impaired perennial crop acreages are less discounted. 

It is almost impossible to lower groundwater salinity without extensive artificial recharge or expensive desalination. So, over time groundwater salinity gradually increases and perennial crop acreage decreases. The loss in total profit over 10 decades from initial groundwater salinity of 500 mg/L to 1,500 mg/L can be several hundreds of million dollars. Salination diminishes groundwater’s ability to serve as a drought reservoir for drier years and eventually makes groundwater unfavorable for agricultural water supply by reducing crop yields.

Interest rates are important (Figure 2). Lower discount rates further increase the value of controlling groundwater salinity by early aquifer recovery, deferring net extraction to the last decades when the initial groundwater salinity is still low (Figure 2.a). When initial groundwater salinity is higher, more water than required is recharged to the aquifer in early decades to slow salination and prolong production, despite some recharged water being wasted to meet the final storage goal (Figure 2.b).

Figure 2. Lower discount rates cause more aggressive groundwater recharge in early decades and shift pumping to the last decades.

A drier climate worsens conditions for irrigated agriculture with groundwater salination. It is the battle between recharging the aquifer to have lower groundwater salinity for middle decades and pumping to irrigate more perennial crops to make more profit in early decades. However, a drier climate dramatically increases the cost of recharging (especially in the first decades) because less available surface water can dilute less groundwater, meaning fewer less-impaired perennial crops can be supported, while less deep percolation from crops requires more artificial recharge in wetter years for aquifer recovery, reducing annual crops. A drier climate further increases the loss from groundwater salinity, by 200 M$ in this example.

Overall, groundwater salinity changes conjunctive water management for decadal timescales, shifting pumping from drier years to wetter years, when more surface water can dilute more saline groundwater for irrigation. Groundwater salinity also changes groundwater management at longer timescales, moving artificial recharge to earlier decades and shifting pumping to later decades (only to avoid water-logging). Even with these changes, agricultural production suffers greatly from groundwater salinity, which reduces crop yields and diminishes groundwater ability to serve as a drought backup.

In undrained parts of California and the world, irrigated agriculture faces problems of excess salinity, even if groundwater overdraft ends.

Dr. Gracie Yao recently completed her PhD in Civil and Environmental Engineering at the University of California – Davis.  Jay Lund is a Professor of Civil and Environmental Engineering at the University of California – Davis

Further reading

Yao, Y. and J. Lund (2021), Managing Groundwater Overdraft – Combining Crop and Water Decisions (without salinity),, January 17, 2021

Yao, Y. and J. Lund (2021), Managing Water and Crops with Groundwater Salinity – A growing menace,, March, 2021

Yao, “Gracie” Yiqing (2020), Managing Groundwater for Agriculture, with Hydrologic Uncertainty and Salinity, PhD dissertation, Department of Civil and Environmental Engineering, University of California – Davis.

Dogan, M., I. Buck, J. Medellín-Azuara, J. Lund (2019). Statewide Effects of Ending Long-Term Groundwater Overdraft in California, Journal of Water Resources Planning and Management, Vol 149, No. 9, September.

Escriva-Bou, A., R. Hui, S. Maples, J. Medellín-Azuara, T. Harter, and J. Lund (2020), Planning for Groundwater Sustainability Accounting for Uncertainty and Costs: an Application to California’s Central Valley, Journal of Environmental Management, Vol. 265, 110426, June 2020.

Faunt, C., ed. (2009). Groundwater Availability of the Central Valley Aquifer, California: U.S. Geological Survey Professional Paper 1766, 225p. USGS Professional Paper 1766: Groundwater Availability of the Central Valley Aquifer, California.

Hansen, J. A., Jurgens, B. C., & Fram, M. S. (2018). Quantifying anthropogenic contributions to century-scale groundwater salinity changes, San Joaquin Valley, California, USA. Science of the Total Environment, 642, 125-136.

Harou, J. and J. Lund (2008). Ending groundwater overdraft in hydrologic-economic systems, Hydrogeology Journal, Volume 16, Number 6, September, pp. 1039-1055.

Howitt, R., Kaplan, J., Larson, D., MacEwan, D., Medellín-Azuara, J., Horner, G., Lee, N. The Economic Impacts of Central Valley Salinity. Final Report to the State Water Resources Control Board Contract. March 2009.

Pauloo, R.A., Fogg, G.E., Guo, Z., Harter, T. (2021), Anthropogenic Basin Closure and Groundwater Salinization (ABCSAL), Journal of Hydrology, Vol. 593, 125787, February 2021.

Pauloo, R.A., Fogg, G.E. (2021), “Groundwater Salinization in California’s Tulare Lake Basin, the ABCSAL model,”, Posted on February 21, 2021    

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Looking for a new challenge? – Retrain as a Delta Smelt

Cool smeltHelp restore one of California’s most endangered species while supporting California’s water supplies in a time of drought.

The Federal government is beginning a program for the unemployed to retrain as much-needed Delta Smelt.  Following a two-day course, candidates will learn to:

  • Seek out turbid waters
  • Spawn in sand at secret locations
  • Surf the tides
  • Make themselves present for counting in mid-water trawls

Major California water projects and water users are preparing to hire successful graduates for 1-2 year non-renewable contracts.  Minimum qualifications:Smelt 2

  • Must be shorter than three inches
  • Swim poorly
  • Smell slightly of cucumber
  • Be translucent

Occupational risks include:

  • Consumption by bass
  • Entrainment by pumps
  • Getting lost in Delta channels
  • Relocation to Southern California

As an endangered species, actual employment conditions will likely comply with State social distancing requirements.

For information, please contact:

Smelt touch

Looking for a new career?

What do you want to do ?

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Field courses help young people see the real world

by Andrew L. Rypel

It was perhaps unsurprising I wound up a field ecologist. Raised in Wisconsin, I spent almost all my childhood free time roaming largely unchaperoned in nature, pre-internet. It was there that I developed a deep love for nature, water and fish that would stay with me my whole life. It was a privileged upbringing. And yet somehow it was years later, when I was 22 and taking a university field course, that I finally figured out I wanted to pursue a career in fish and ecology. It’s unclear how many biologists trace their paths back to experiences like these, but I suspect there are many. Field courses are so impactful, and we need them now, more than ever before. 

As a young college student, I struggled at my mid-sized liberal arts college to find a curricula that connected my outdoors interests (nature, fishing, camping, hiking) together. Years later, I recognized that field broadly as ecology, but at the time, I didn’t know that’s what I was searching for. Most of the science courses and majors at my institution were annoyingly pre-health. I briefly toyed with the idea of a double major in English and a natural science field. Eventually I declared the best major I could find – environmental science (awarded through the geology department) with biology as a minor. At that time, environmental programs were somewhat rare at many US institutions, so I was happy enough I had majored in something vaguely reflecting my values.

Group photo from 2002 “Biology of the Southern Appalachians”. Yours truly looking dour and scraggly in the back row. Photo from Meredith Latimer.

I finally took my first real field course during my Master’s program in fisheries several years later at Auburn University (War Eagle!). The course was Biology of the Southern Appalachians, taught by Professor George Folkerts. It hadn’t been offered in years, and I had privately heard it was something special. Now, I could write an entire series of blogs on George, but most people who know Auburn, or natural history of the southeastern USA, or Tuesday trivia night in Auburn – all knew George. He was gentle, patient, brilliant, and a walking encyclopedia of biodiversity and ecology, especially rare and declining organisms like bog plants, salamanders, turtles, beetles, arthropods of longleaf forests – basically everything. I consider him one of my “academic parents”, and he was later a close friend.

George took about 15 students including myself (~50/50 undergrad/grad) in vans for the better part of two months collecting plants and animals from Auburn, AL northeast to parts of Maryland. It was one of the best periods in my life. To help write this blog, I resurrected my old field notebook from the course to recall some of what we collected. For example, I see that we collected a black racer snake, hiked through a stand of smoke trees, observed cave bats, snorkled for freshwater mussels, observed rare bog turtles, collected aquatic insects, seined for fishes, captured a jumping mouse with our bare hands, used live traps for small mammals, sampled terrestrial snails, collected at least five species of cockroach (!), identified millipedes, collected a baker’s dozen species of salamanders, hiked to the top of Clingman’s Dome to see the completeness of the damage done to forests by acid rain and the balsam woolly adelgid, visited a cataract bog with stands of live mountain sweet pitcher plants (I described them as uniformly tall, beautiful, and with insects trapped in the pitchers). And this list was just for the first half of our trip!

From the dusty bottom of moving boxes – my field notebook from 2002. 

One afternoon, early in the trip, we were hiking through Joyce Kilmer National Forest in NC – famous for its old growth tulip trees. We’d been hiking for an hour or so when George stopped at the base of a large tulip tree. He sat down, pensively, and swigged some water out of his canteen. He then said something I’ve never forgot

“Don’t let anyone tell you to get into the real world. Science and academics is the search for knowledge. And it’s more real than anything you’ll ever find in the “real world”.”

I’d never considered science as a career before then. Was I good at that? I had always figured I would get a fisheries degree, find a great job at a state or federal agency, and move back near home. Over time, I came to learn that I was good at science, and it became a passion. I wanted to understand how things worked – and I wanted to use that information to improve conservation, especially for my beloved fishes.

Over the years, I’ve come to realize my experience wasn’t unique. Many students pursue environmental and science-based careers after taking field courses. We observe this frequently at the Center for Watershed Sciences at UC Davis. Many of our students, alumni, and staff began their journeys after taking Ecogeomorphology (EcoGeo for short). The brain child of Jeff Mount and Peter Moyle, EcoGeo is an interdisciplinary idea, where upper level undergraduate students study watershed issues in multidisciplinary teams. The course culminates with an extended summer field trip to the watershed where field research is conducted. UC Davis teams have traveled to places like the Kobuc River (AK), Santa Cruz Island (CA), Grande Ronde (OR/WA), Skeena River (BC), Copper River (AK), and the Grand Canyon (several times). So many UC Davis students have started careers with these courses; it is one of the great and enduring legacies of the Center, and one that I would like to see multiplied in coming years.

UC Davis EcoGeo students and instructors are gathered in the Grand Canyon in the nightly Circle of Science, where each night a student makes a presentation on some issue relevant to river management. Then everyone discusses how the topic relates to different disciplines. Photo credit: Joe Proudman

We know these courses are effective at generating extraordinary learning outcomes. Elkins and Elkins (2007) demonstrated that for introductory geology information, there was significantly higher improvements in basic geoscience understanding for field course students compared to 29 other introductory geoscience courses from across the United States. Durrant (2015) showed that aside from basic intellectual gains, students of field courses themselves realized integrative learning gains had taken place while attending a field course. These results suggest field courses also work on sharpening metacognition or ‘thinking about how you think’ – considered one of the higher forms of human thought. 

Finally, field courses can reset our values framework. For many young people, especially those without privilege, nature has never been fully experienced. Our society, especially in California, is increasingly urban, populated, and disconnected from nature and wilderness. We work and manage within reconciled contexts – urban parks, working landscapes, backyard ecology. These frameworks are necessary to realistically preserve and manage the ecological function we have left. Yet there is also a need to visit, study and protect the best – wild places – where the true real word is right in front of you. It is important for humans to experience these environments. 

In an alarming study by Soga and Gaston (2016), we see that children especially are having decreased basic contact with nature. For example, the percentage of children who had never fished increased from ~20% in 1998 to ~50% in 2009. The percentage of children who had never climbed a mountain increased from ~50% in 1998 to ~70% in 2009. Other simple indicators of participation (climbing trees, catching bugs, birdwatching) have all declined in young people over time. This is scary – and may do us in faster than many other existential threats that we worry about! 

It is rightful to ask, “How will our society be capable of protecting nature if many have never fully experienced it?” Field courses don’t solve this problem alone, but they do address the root of the problem for those who take them. Field courses also represent an opportunity to aid in diversifying the fields of natural resource management and conservation, which are notably lacking in recruitment and retention of women and people of color. For our part, we will journey on. Maybe you’ll see some of our graduates out on the river, or fighting for science-based decision-making in a meeting or public forum near you.

Further reading

UC Davis Center for Watershed Sciences education webpage,

Durant, K.L. 2015. The Integrative Learning Value of Field Courses. Journal of Biological Education 49: 385-400.

Elkins, J.T., and N.M.L. Elkins. 2007. Teaching Geology in the Field: Significant Geoscience Concept Gains in Entirely Field-based Introductory Geology Courses. Journal of Geoscience Education 55: 126-132.

Soga, M., and K.J. Gaston. 2016. Extinction of experience: the loss of human-nature interactions. Frontiers in Ecology and the Environment 14: 94-101.

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That Time Warren Buffett Got Involved in California Water

by Andrew L. Rypel

Famous quote by Warren Buffett

As if 2020, wasn’t completely strange enough, it wound up also being a time when Warren Buffett was plunged headlong into California water. Buffett of course is an American business tycoon – primarily an investor, and currently the 4th richest person on the planet. Although 90 years old, Buffett continues as chairman and CEO of Berkshire Hathaway – a multinational holding company headquartered in Omaha, Nebraska – Buffett’s hometown. Buffett is also a mega-philanthropist that has pledged to give away 90% of his wealth, mostly through the Bill & Melinda Gates Foundation. Thus it was with some surprise that last year Warren Buffett found himself recently embroiled in a hugely important California water issue – removal of the Klamath River dams.

The socioecological effects of dams on the Klamath River have been massive, almost uniformly negative, and ongoing. The Klamath watershed has been estimated as the third-most productive drainage on the West Coast for salmon and steelhead. Yet salmon runs declined substantially over the last century in part because dams fragment and isolate salmon from their historical upland spawning habitats (Brown et al. 1994, Hamilton et al. 2016). Other complicated ecological problems that harm salmonids persist in the basin and can vary by taxa and watershed position (Quiñones et al. 2014). Finally, climate change and certain aspects of current dam operations increase vulnerability of salmon to disease, notably C. shasta (Som et al. 2019, Lehman et al. 2020). 

Klamath River before and after installation of Iron Gate Dam. Photo source:

Indigenous peoples have disproportionately dealt with the brunt of ecological impacts from dams on the Klamath River (Most 2007, Norgaard and Reed 2010, Hormel and Nogaard 2009). Fish kills and declining salmon populations have left indigenous nations and fishers scrambling to adapt, and developing legal strategies for defending their ancestral heritage and sacred natural resources. And as if fighting legal battles for the river and salmon weren’t enough, examples abound of tribal members being harassed for hunting and fishing using traditional methods. Technicalities and cover-ups were used to arrest and harass indigenous peoples and negate fishing rights. The landmark Boldt Decision of 1974 re-affirmed the rights of indigenous people to hunt and fish using ancestral methods, and to also co-manage their fisheries with the US and its state governments. Nonetheless, various other methods and campaigns were created after the Boldt Decision to functionally invalidate tribal fishing rights. These battles mirror unsavory behavior in other inland fisheries following the Boldt Decision, such as with the walleye fishery in the Ceded Territory of Wisconsin (Nesper 2002).

Plans to remove four large hydroelectric dams along the Klamath River have been developing for some time. The genesis of the Klamath Dam removals is multi-faceted. Part of it comes from endangered species like salmon and the native Klamath River suckers having gained protective ascendancy under the law. In addition, tribes have been exercising their senior water rights, which can date back to original treaties – making tribal nation owners some of the oldest water right holders on the river. However, there is also an important business case for removing the dams. Like all dams, these four (Iron Gate, John C. Boyle and Copco Dams 1 & 2) have been ageing. And unlike fine cheeses and wines, dams tend to get worse with age – not better. For example, there are concerns about structural stability and costs to rehabilitate or retrofit them for functionality and safety in the coming century. Ultimately, to renew the operating license for the dams, PacifiCorp would have had to shell out $400M for upgrades to ensure compliance. Part of this compliance would have included installation costs for fish ladders at each of three dams for fish migration. Removing the dams would likely cost less, but the theme is the same – PacifiCorp is the major entity on the hook.

Photo of salmon carcasses taken 9/28/02 along the banks of the Klamath River. Photo source: Ron Winn/The Herald And News via AP

Berkshire Hathaway, under Buffett’s leadership, acquired Pacificorp in 2006 for $9.4B from Scottish Power – a UK company. And while Buffett made his name on a reputation for acquiring good companies and letting them run more or less autonomously, that is not how the Pacificorp acquisition unfolded. Rather, the day of the merger with MidAmerican (Birkshire’s energy holdings subsidiary), Pacificorp was reorganized into three separate units and an East and West Division. Almost all top managers were replaced and a top-down chain-of-command structure established to run the company in the Birkshire way. That is – using financial discipline, respecting the chain-of-command, and focusing on the bottom line. Thus, the history of Birkshire’s involvement in the Pacificorp yielded a window into how the company might approach the Klamath dams quagmire.

A 2016 accord provided hope that the removals would indeed occur. Under this agreement, Pacificorp would transfer its federal hydroelectric licenses for the dams to the Klamath River Renewal Corporation – a nonprofit coalition of stakeholders deeply invested in the project. The removal cost is estimated at $450M, so the cost is more than the $400M it would take for PacifiCorp to upgrade the infrastructure – but not much more. Under the 2016 agreement, Pacificorp customers would contribute $200M for the project while the utility would avoid additional liability costs. The additional $250M would come from a 2014 water bond approved in California.

Artistic rendering of the Klamath River at Copco Lake before versus after dam removal.

But things got spicy again in summer of 2020. The Federal Energy Regulatory Commission (FERC) decided to approve the transfer of the FERC license from PacifiCorp to the Klamath River Renewal Corporation, but on the stipulation that PacifiCorp remain as co-licensee. FERC expressed concerns that while the new nonprofit could likely carry out the work, they would undoubtedly be faced with issues they may not be equipped to deal with. This was a game changer because it meant PacifiCorp and its rate payers, and by proxy, Berkshire, would be on the hook for liabilities from any fish kills, lawsuits, blue green algae blooms, and other issues. 

Copco Dam on the Klamath River, one of the four large dams slated to be removed. Photo source:

Fortunately, an accord was again struck in fall of 2020 with Buffett and Berkshire. Governors Gavin Newsom (CA) and Kate Brown (OR), together with partner tribes and NGOs, pushed Berkshire and Buffett hard towards a new solution. In the new agreement, California and Oregon will sign on as co-licensees of the dams alongside the Klamath River Renewal Corporation. The stipulation is that the two states and PacifiCorp will split costs equally should the project overrun funds set aside for the project. However, the deal still requires approval of the FERC board that rejected the previous proposal, so nothing is final yet. At a press conference announcing the deal, the Chairman of the Yurok tribe, Joseph James articulated the following (watch also in video below): 

“To me this is who we are. We have a free-flowing river, just as those who have come before us, and here now for those generations to come. This is a place in time for our prayers, our songs, our dances, our ceremonies which will continue with more water and more fish. Our ecosystem will continue to heal and provide substance to all of us. We are connected with our heart and our prayers to these creeks, lands, animals, and our way of life will thrive with these dams being out. We’ll be able to have salmon and our traditional food once again because there is no other place than our villages and sense of place than along the Klamath River. I’d also like to highlight and discuss who we are. We’re a prayer people. We’re traditional people. We’re a natural resource tribe. It is our duty and our oath to bring balance to the river. In this effort, it is fulfilling that duty.”

The Berkshire Energy Chair Greg Abel later commented that “It was an honor to be there for the important milestone, which underscored his company’s commitment to “economic, social and racial justice.

As is often the case, the road to water policy change in California has been long and winding. Some have pointed out that the deal isn’t perfect, claiming that the new deal struck is a bad one for California and Oregon taxpayers that are now on the hook for costs and liability. The dam removals also cut into the capacity to have a more reliable source of energy available for an ailing electric power grid. However, the Klamath dams are an example of what it takes to build real solutions for complex water problems. Critical decisions that were difficult to predict threw wrenches into already complicated processes. There will be more detours and problems in the coming years. Stakes are high. Patience is essential. Compromises were made. Yet culture, economics, politics, and ecology collide to pave and sometimes divert the road towards something quite special in California – this should be celebrated. The solution struck seems reasonable and ensures the Klamath River will finally have a chance to recover. We hope to provide more blogs on the Klamath dam removals and related Klamath basin topics in the coming years.

Klamath River. Photo source:

Further Reading

Brown, L. R., P. B. Moyle, and R. M. Yoshiyama. 1994. Historical decline and current status of coho salmon in California. North American Journal of Fisheries Management 14(2):237-261.

Hamilton, J. B., D. W. Rondorf, W. R. Tinniswood, R. J. Leary, T. Mayer, C. Gavette, and L. A. Casal. 2016. The persistence and characteristics of Chinook salmon migrations to the upper Klamath river prior to exclusion by dams. Oregon Historical Quarterly 117(3):326-377.

Hormel, L. M., and K. M. Norgaard. 2009. Bring the salmon home! Karuk challenges to capitalist incorporation. Critical Sociology 35(3):343-366.

Lehman, B., R. C. Johnson, M. Adkison, O. T. Burgess, R. E. Connon, N. A. Fangue, J. S. Foott, S. L. Hallett, B. Martinez–López, and K. M. Miller. 2020. Disease in Central Valley Salmon: Status and Lessons from Other Systems. San Francisco Estuary and Watershed Science 18(3).

Most, S. 2007. Salmon people: crisis and continuity at the mouth of the Klamath. California History 84(3):5-22.

Nesper, L. 2002. The Walleye War: The Struggle for Ojibwe Spearfishing and Treaty Rights. University of Nebraska Press, Lincoln, Nebraska USA.

Norgaard, K. M., and R. Reed. 2010. Salmon Feeds Our People: Challenging Dams on the Klamath River. Conservation International.

Quiñones, R. M., M. Holyoak, M. L. Johnson, and P. B. Moyle. 2014. Potential factors affecting survival differ by run-timing and location: linear mixed-effects models of pacific salmonids (Oncorhynchus spp.) in the Klamath River, California. PloS One 9(5):e98392.

Som, N. A., N. J. Hetrick, R. Perry, and J. D. Alexander. 2019. Estimating annual Ceratonova shasta mortality rates in juvenile Scott and Shasta River coho salmon that enter the Klamath River mainstem. U.S. Fish and Wildlife Service, Technical Report.

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California’s New Drought

By Jay Lund, Andrew L. Rypel, and Josue Medellin-Azuara

As March begins to drag on with little precipitation in the forecast and few weeks left in California’s traditional wet season, we are in another dry year. This is California’s second dry year in a row since the 2012-2016 drought.  Statistically, California has the most drought and flood years per average year than anywhere in the US.  This statistical fact seems to becoming increasingly extreme, as predicted by many climate change models.

Figure 1. Some major current reservoir levels today and over the last few years, including the 2012-2016 drought (US Army Corps of Engineers)

As Californians have adapted to drought over the last 150 years, drought damages and losses have changed.  Traditional drought water supply losses to cities and agriculture have fallen tremendously, as a percent of urban and agricultural economies.  The 2012-2016 five-year drought had total direct damages of about $10 billion statewide, without direct loss of life (Lund et al 2018).  For a state economy exceeding $2 trillion/year, drought impacts were often large locally, but statewide water shortage impacts were less than 0.09% of the state’s economy.  Traditional drought impacts are important, but are manageable if managed well (we sometimes have trouble with this).

Yet, wildfires in the four following years worsened considerably from the drought-related deaths of over a hundred million forest trees and other factors.  These wildfires caused a record of over $55 billion in direct property losses and 175 direct deaths, with many weeks of widespread air pollution with still larger and more widespread economic and health impacts, including estimates of more than 1,000 additional deaths.  Additional health impacts from these events are likely chronic and poorly understood (such as increased risk of cancer and lung damage from particulate inhalation). The drought was not responsible for all these wildfire impacts, but probably some substantial share of them.

Arguably, the 2012-2016 drought’s impacts occurred mostly after the drought ended.  And most economic and health drought impacts were to people who suffered no water shortages.

California’s new drought, with higher temperatures and greater resulting wildfire and air pollution impacts, and perhaps other untold ecological and human health impacts, is a new aspect and era for drought in California.  Wildfire-related air pollution affects almost everyone in California, even the majority who don’t see traditional water shortages – but do see often-delayed drought-related shortages of safe air to breathe.

State of this drought today. Today, northern California has about 52% of average precipitation for this time of year.  Snowpack levels are at 62% of average, but this is less important because California’s reservoirs are only 57% of long term average total storage.

Some of California’s major reservoirs are as low in this second year of drought as they were in the third and fourth years of the 2012-2016 drought.  Today, storage in Shasta reservoir is 2.28 million acre feet. Since 2012, only 2014 had a lower storage at this time of the year (at 1.94 million acre feet). These conditions pose major challenges for endangered fishes like winter-run Chinook salmon that have extended freshwater rearing periods during the summer. If temperatures are as warm as the last drought, we might see problems supplying cold water for young winter-run salmon below Shasta dam, a problem which killed more than 90% of this salmon run in 2014 and 2015.

High drought temperatures seem likely again, as temperatures have been high for recent years, including the previous drought.  In the last drought, higher temperatures were responsible for about 25-30% of the drought’s total moisture deficit, which increased tree mortality in forests.  Higher temperatures also make it harder to maintain cold water for salmon and other species.  Less cold water is available, and it warms faster as it travels downstream.  Increasing temperatures have been noted as a major challenge for the embattled delta smelt, which is near extinction.  Its close threatened relative, longfin smelt, also is sensitive to temperature (Yanagitsuru et al. 2021). We have barely begun to understand, detail, or try to manage the more complex effects of warm droughts, especially for ecosystems.

Groundwater Redux and Future

The biggest traditional drought impacts are likely to occur from increased agricultural groundwater pumping to partially compensate for reduced surface water supplies: 

  • Many rural community and household wells will be left dry or become contaminated as deeper wells pull nitrate contamination deeper (Stone and Gailey 2019). 
  • Some environmental surface flows will be drawn underground by lower aquifer levels.
  • Additional land subsidence will reduce capacities for surface canals and floodways.
  • Accumulated overdraft from additional drought years and the years elapsing during this drought will make achieving SGMA groundwater sustainability objectives harder without additional reductions in agricultural acreages in deeply overdrafted basins.  (The magical magnitudes of water espoused from Flood-MAR will become still less plausible, even though plausible amounts remain useful.  Droughts often test our assumptions.)

The Delta

The Delta is always a pivotal weak point in California’s water system.  Managers are always very attentive to Delta management and its drought challenges.  Much will depend on details we don’t know yet about this drought.  A few things to watch:

  • Reduced water supplies from the Delta are certain in the drought, but the exact amount of reductions won’t become clear for some time.
  • Warmer temperatures and lower Delta channel flows seem to have accelerated the spread of invasive aquatic plants during the last drought.  This might well happen again.  These same conditions also could increase harmful algal blooms, with both water quality and potential public health impacts, and are being studied by a variety of agency and independent scientists.
  • Delta salinity barriers are likely under continued severe conditions. 
  • Struggles for native Delta fishes remains a perennial issue which peaks in times of drought.  Will this be the true end of Delta Smelt?

Other usual, but still important, impacts

  • California’s hydropower generation, usually about 15% of state electricity production, will fall.
  • Continued shifts in forest and rangeland ecosystems can be expected.
  • Agricultural water shortages, and resulting unemployment and financial stress to irrigation districts.
  • Local urban water shortages, and financial stress to water utilities from reduced water sales and perhaps to poorer water customers
  • Water markets – prices up
  • Water right curtailments – seem likely, with details becoming clearer in the months ahead.

Drought in California is always an old story and a new one.  Alas, we probably will need the N-95 masks episodically after the pandemic to combat drought impacts in the coming years.

Some data sources

Here are some data-rich sites useful for folks who want to follow the drought.  The main overall go-to data site is DWR’s excellent CDEC, – Bon apetit!



Reservoir levels:

A nice table of major reservoir storages throughout California, produced at the end of each month.

A nice table comparing major reservoir levels for this time over the last few years, including the previous drought.

Jay Lund and Andrew Rypel are professors and Co-Directors of the Center for Watershed Sciences at the University of California – Davis.  Josue Medellin-Azuara is a professor at the University of California – Merced.

Happy Pi Day! (3/14)

Further reading

Durand JR, Bombardelli F, Fleenor WE, Henneberry Y, Herman J, Jeffres C, Leinfelder–Miles M, Lund JR, Lusardi R, Manfree AD, et al. 2020. Drought and the Sacramento-San Joaquin Delta, 2012–2016: Environmental Review and Lessons. San Franc Estuary Watershed Sci. 18(2). doi:10.15447/sfews.2020v18iss2art2.

Lund J, Medellin-Azuara J, Durand J, Stone K. 2018. Lessons from California’s 2012–2016 Drought. J Water Resour Plan Manag. 144(10):04018067. doi:10.1061/(ASCE)WR.1943-5452.0000984.

Stone, K. and R. Gailey (2020),Economic Tradeoffs in Groundwater Management During Drought,”, June 10, 1919.

Ullrich, P.A., et al. (2018), “California’s Drought of the Future: A Midcentury Recreation of the Exceptional Conditions of 2012–2017”, Earths Future. 2018 Nov; 6(11): 1568–1587.

Woodhouse, C. A., Pederson, G. T., Morino, K., McAfee, S. A., and McCabe, G. J. (2016), Increasing influence of air temperature on upper Colorado River streamflow, Geophys. Res. Lett., 43, 2174– 2181, doi:10.1002/2015GL067613.

Yanagitsuru, Y., et al. (2021), “Effects of temperature on hatching and growth performance of embryos and yolk-sac larvae of a threatened estuarine fish: Longfin smelt (Spirinchus thaleichthys),” Aquaculture, Vol. 537.

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Managing Water and Crops with Groundwater Salinity – A growing menace

by Yiqing “Gracie” Yao and Jay Lund

Salinity is an eventual threat to agriculture and groundwater sustainability in parts of California, and other irrigated parts of the world. Irrigation, lower groundwater levels, and natural conditions have dramatically increased groundwater salinity in parts of California over the last 150 years (Hansen et al. 2018). Nearly two million tons of salt accumulates per year in the San Joaquin Valley (CV-SALTS), where 250,000 acres of irrigated land have been fallowed, 1.5 million acres are potentially salt-impaired (Great Valley Center 2005), with $1.2 – $2.2 billion/year losses by 2030 (Howitt et al. 2009) without management. Managing groundwater with salinity can differ fundamentally from conjunctive water management without salinity, which was summarized in a previous blog post.

Salts accumulate in soils and shallow groundwater in arid and semi-arid areas because higher evapotranspiration rates and lower precipitation leave salt in the soil, requiring more irrigation water (also containing salts) to leach soil salinity to groundwater or drainage systems. However, without drainage from a basin, as occurs when low groundwater tables prevent salt drainage to rivers, soil salinity collects in underlying aquifers and groundwater salinity can only increase with time (Pauloo and Fogg 2021). 

With every pumping-and-recharge cycle, the groundwater becomes saltier. This is common in western parts of California’s San Joaquin Valley (Hansen et al 2018). Salts in soil and irrigation water reduce crop yield and quality, with foreseeable salinization and agricultural losses for the San Joaquin Valley.

Groundwater salinity and conjunctive use of surface water and groundwater

A recently-completed hydro-economic optimization model examines conjunctive water use and cropping patterns for extensive irrigated agriculture with increasingly saline groundwater (Yao 2020). It models crop planting and water management to maximize profits over a 10-year period with surface water availability varying from dry to wet years (event 1 = driest to event 5 = wettest), considering salinity’s harm to crop yields. The modeling was applied for conditions similar to the western San Joaquin Valley. For simplification, the model assumes blended irrigation water to reduce salinity effects on crop yields. 

Model results show that conjunctive use with more saline groundwater differs fundamentally from conjunctive use without salinity (Figure 1). With little groundwater salinity, semi-arid agricultural regions tend to pump more groundwater in drier years to supplement scarcer surface water. As groundwater become saline enough to reduce crop yields, economically optimal conjunctive use shifts to pumping less in drier years and pumping more in wetter years (Figure 1), when surface water can dilute more saline groundwater.

Figure 1. More saline groundwater fundamentally shifts groundwater operations from pumping more in dry years to pumping more in wetter years, when more saline groundwater can be diluted with fresher surface water (Yao 2020), while maintaining groundwater storage.

Cropping patterns and crop water use with groundwater salinity

Figure 2 shows water use for perennial and annual crops over the range of dry to wet years for different groundwater salinities.

At low groundwater salinities, more perennial crop acres are grown. As groundwater salinity rises to the salt tolerance of the perennial crop, groundwater’s ability to furnish useable water for dry years to grow perennial crops diminishes rapidly, because driest years have the least surface water to blend with more saline groundwater. Otherwise, perennial crop yields decrease uneconomically. Reduced pumping in drier years substantially reduces a region’s ability to support perennial crops and can eliminate annual crops with lower value in dry years.

To maintain groundwater levels, groundwater pumping increases in wetter years when more surface water is available to dilute more saline groundwater, but the additional pumping is used to grow lower-value annual crops. With higher groundwater salinities, annual crop acreage in wetter years is limited by irrigation water salinity. If all available water (surface water plus groundwater) is used to grow crops in the wettest years, the additional deep percolation forces more groundwater pumping to avoid waterlogging. More pumping increases salinity in irrigation water as the amount of surface water is fixed for each water year type, while more saline irrigation water reduces crop yields. Therefore, fewer annual crops are planted, and excess water must be disposed from the basin (brown arrows in Figure 2). 

Figure 2. Relationship between crop water requirement and irrigation with no overdraft. Brown arrows in the wettest year for high salinity cases are unused water externally drained.

Economic value of water with groundwater salinity

Table 1 summarizes how groundwater salinity affects the economic value of surface water and groundwater. When groundwater salinity is low, groundwater has greater value, as it can help support more perennial crops in dry years (when surface water is unavailable). With higher groundwater salinity, this drought buffering is unavailable and becomes a cost to agriculture, as pumping makes irrigation water too salty for perennial crops, reducing both crop yield and profit. At the two highest groundwater salinities, groundwater is so undesirable (in this model) that saline groundwater is pumped only for discharge outside the basin to avoid waterlogging (imposing pumping and disposal costs without profit).

Table 1. Summary of economic values of water ($/AF) in different hydrologic events with different groundwater salinities for a no-overdraft goal.

Salination of groundwater makes surface water more economically valuable, as it makes useable water scarcer overall. Surface water availability in the driest years limits the extent of profitable perennial crops, making farmers willing to pay more for this water (roughly the cost of desalted water in this case). The range of economic values for surface water widens across years as groundwater becomes more saline. For low salinities, the availability of fresh groundwater dampens water price variation across years. But with more saline groundwater, the variability in surface water’s economic value expands, rising for dry years and declining, eventually to zero, for wetter years. 

A drier climate further increases the value of surface water in the driest year and reduces agricultural profit. When groundwater salinity is low, overall usable dry-year water scarcity is less, and we value groundwater more. However, if groundwater salinity is too high, groundwater reduces agricultural profitability for drier climates.

Artificial recharge in the context of groundwater salinity

From Figure 2, high groundwater salinity leads to externally discharging water in the wettest years to physically remove both salt and excess recharge (deep percolation) from the basin. In such cases, raising water tables can be more profitable (if waterlogging is not an issue), by reducing need to pump (and waste) saline groundwater, having the same acreages of perennial crops with more lower-value annual crops in wettest years (Figure 3) as no pumping occurs in these years and irrigation water salinity is not a concern anymore. Artificial recharge of fresh surface water also can reduce groundwater salinity, at least locally, to make more groundwater fresher for dry year use in the future. Starting artificial recharge with fresh surface water early can slow groundwater salination and reduce its effects on water and crop management.

Figure 3. With high groundwater salinity (Cgw = 6,000 mg/L), mild aquifer recovery can be more profitable. Also, artificial recharge somewhat dampens the difference in surface water variability in wetter years.

Unlike pumping decisions, which are limited by irrigation water salinity, artificial recharge occurs in wetter years when perennial crops are irrigated only by fresh surface water. Therefore, artificial recharge still serves the original function of conjunctive use to dampen surface water variability. Annual crop acreage in years without artificial recharge should never exceed annual crop acreage in years with artificial recharge, and annual crop acreage is the same across years with artificial recharge (Figure 3).


For parts of California where salts accumulate in groundwater without drainage from the basin (mostly western San Joaquin Valley), growing groundwater salinity seems destined to bring a somber future for agriculture. Here eventually, salinizing groundwater will have diminishing ability to serve as a drought reservoir for drier years, and perennial crop acreage will become limited by surface water available in drier years, with greater annual crop acreage fluctuations. Profitable agriculture will still exist, but will be smaller, less profitable, and more variable across wetter and drier years. Though costly, earlier restoration of the aquifer levels, with reduced pumping and increases surface water recharge, can slow salination of groundwater and prolong the value of the aquifer for agriculture.

Many variants of this problem and solutions can be explored; some will be helpful.  Desalting of groundwater for irrigation will continue to be intensely explored and advocated, but will always remain expensive and unsuitable for lower-valued crops.  There is no cheap and permanent escape from the Valley’s water and salt balance problems.

Salinity accumulation is an ancient menace for irrigated agriculture, from ancient Mesopotamia to the present day. After groundwater overdraft is tamed, groundwater salinity will drive changes in groundwater management and overlying agriculture. 

Dr. Gracie Yao recently completed her PhD in Civil and Environmental Engineering at the University of California – Davis.  Jay Lund is a Professor of Civil and Environmental Engineering at the University of California – Davis

Further Reading

Yao, Y. and J. Lund (2021), Managing Groundwater Overdraft – Combining Crop and Water Decisions (without salinity),, January 17, 2021

Yao, “Gracie” Yiqing (2020), Managing Groundwater for Agriculture, with Hydrologic Uncertainty and Salinity, PhD dissertation, Department of Civil and Environmental Engineering, University of California – Davis.

Dogan, M., I. Buck, J. Medellín-Azuara, J. Lund (2019). Statewide Effects of Ending Long-Term Groundwater Overdraft in California, Journal of Water Resources Planning and Management, Vol 149, No. 9, September.

Escriva-Bou, A., R. Hui, S. Maples, J. Medellín-Azuara, T. Harter, and J. Lund (2020), Planning for Groundwater Sustainability Accounting for Uncertainty and Costs: an Application to California’s Central Valley, Journal of Environmental Management, Vol. 265, 110426, June 2020.

Faunt, C., ed. (2009). Groundwater Availability of the Central Valley Aquifer, California: U.S. Geological Survey Professional Paper 1766, 225p. USGS Professional Paper 1766: Groundwater Availability of the Central Valley Aquifer, California.

Hansen, J. A., Jurgens, B. C., & Fram, M. S. (2018). Quantifying anthropogenic contributions to century-scale groundwater salinity changes, San Joaquin Valley, California, USA. Science of the total environment, 642, 125-136.

Harou, J. and J. Lund (2008). Ending groundwater overdraft in hydrologic-economic systems, Hydrogeology Journal, Volume 16, Number 6, September, pp. 1039-1055.

Howitt, R., Kaplan, J., Larson, D., MacEwan, D., Medellín-Azuara, J., Horner, G., Lee, N. The Economic Impacts of Central Valley Salinity. Final Report to the State Water Resources Control Board Contract. March 2009.

Marques, G., J. Lund, and R. Howitt (2010). Modeling Conjunctive Use Operations and Farm Decisions with Two-Stage Stochastic Quadratic Programming, Journal of Water Resources Planning and Management, Vol 136, Issue 3, pp. 386-394.

Pauloo, R.A., Fogg, G.E., Guo, Z., Harter, T. (2021), Anthropogenic Basin Closure and Groundwater Salinization (ABCSAL), Journal of Hydrology, Vol. 593, 125787, February 2021.

Pauloo, R.A., Fogg, G.E. (2021), “Groundwater Salinization in California’s Tulare Lake Basin, the ABCSAL model,”, Posted on February 21, 2021

Reilly, T., K. Dennehy, W. Alley, and W. Cunningham (2008). Groundwater Availability in the United States: U.S. Geological Survey Circular 1323, 70p. USGS Circular 1323.

Singh, A (2014). Conjunctive use of water resources for sustainable irrigated agriculture, Journal of Hydrology, Volume 519, Part B, pp. 1688-1697, November 2014.

Zhu, T., G. Marques, and J. Lund (2015). Hydroeconomic Optimization of Integrated Water Management and Transfers under Stochastic Surface Water Supply, Water Resources Research, Vol 51, Issue 5, pp. 3568-3587.

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Celebrating Black Scientists in Fisheries & Biology

By Kim Luke, Christine Parisek, Rachelle Tallman, Marissa Levinson, Sarah Yarnell, Miranda Bell Tilcock, Andrew Rypel, and Jay Lund

In honor of Black History Month, the Center for Watershed Sciences would like to highlight the contributions of Black scientists in our field. These prominent researchers have not only pushed the social and scientific boundaries of fisheries biology, but have also acted as dedicated mentors. We recognize that scientists of color, and women, experience discrimination and have had more strenuous journeys to succeed in their fields. Out of respect for their lived experiences, the focus of this article is to share their important work, not speak on behalf of their experiences as scientists of color.  

First in her Field

Dr. Roger Arliner Young was a marine biologist, and the first Black woman to receive a PhD in zoology in 1940 from the University of Chicago. Dr. Young was also the first Black woman in her field to have her research paper “On the Excretory Apparatus of Paramecium” published in the journal Science in 1926. She was the student of another prominent Black marine biologist, Dr. Ernest Everett Just, who recruited Young during her undergraduate studies at Howard University. Dr. Young assisted Dr. Just with his pioneering experiments on marine organism fertilization at the Marine Biological Laboratory at Woods Hole. She went on to teach at several universities and head the Department of Zoology for Dr. Just while he was overseas. 

Fisheries & Anthropogenic Issues

Dr. Daniel Pauly is a fisheries biologist and professor at the University of British Columbia. He has worked all over the world, focusing his research on overfishing and global fish trends, particularly in developing parts of the world. Some of Dr. Pauly’s notable contributions include the fish encyclopedia FishBase, the modeling program Ecopath, and the research initiative for fisheries data, Sea Around Us. One of his papers, “Fishing down marine foodwebs” is widely considered to be one of the preeminent classics, and required reading for many fisheries courses. This paper was also included in the book “Foundations of Fisheries Science” that features reprints of critical fisheries work. Dr. Pauly has also written many books on fisheries and marine ecosystems, and has been given seven honorary doctorates from universities in Europe and Canada.

Working in the Public Sector

Dr. Mamie Parker is a fish and wildlife biologist, and was the first African American Fish and Wildlife Service Regional Director. She also served as FWS Chief of Staff, and Assistant Director of Habitat Conservation/ Head of Fisheries. One of the many highlights of Mamie’s work with fish habitat management, was her role in negotiating with General Electric to clean up the Hudson River. Dr. Parker now works as a principal consultant, success coach, and public speaker.

Population Genetics in Fisheries

Dr. Sheila Stiles has been a research geneticist at the Northeast Fisheries Science Center for more than 50 years. Dr. Stiles received a B.S. in Biology from Xavier University (Louisiana, USA), an M.S. from University of Connecticut (Storrs, USA), and finally, Ph.D. from the University of Massachusetts (Amherst, USA) in fisheries and genetics. Dr. Stiles was the first African American woman hired at the Milford Laboratory which later became part of the Northeast Fisheries Science Center when NOAA was created in 1970. Dr. Stiles is the project leader of a collaborative research program with a tiered focus on mussel breeding, molecular genetics, and field work in order to provide various economic and conservation applications. Dr. Stiles is also strongly involved in recruitment, retention, and mentoring activities of young scientists from elementary to college level.

Science meets Management

Dr. Cecil Jennings is Unit Leader at the USGS Georgia Cooperative Fish and Wildlife Unit in the Warnell School of Forestry & Natural Resources at the University of Georgia. He holds a bachelor’s degree in biology, natural science, and conservation from Carthage College, a master’s degree in wildlife and fisheries ecology from Mississippi State University, and a Ph.D. in fisheries science from the University of Florida. He has studied fisheries for over >32 years.

Dr. Jennings is widely known for developing science for improving conservation management of freshwater fishes throughout North America. He has worked extensively with rare and diverse fish species in the southeastern USA, but also fisheries with intense connections to people and communities. He has highly cited papers detailing aspects of the biology and management of sturgeons, suckers and paddlefish. Over his career, Dr. Jennings has mentored a small army of graduate students, post-doctoral research associates, and technical staff who continue to protect and manage fisheries for future generations. In 2020, Dr. Jennings was selected as the 2nd Vice President of the American Fisheries Society.

Founder of “Minorities in Aquaculture”

Imani Black founded Minorities in Aquaculture. Imani is currently a faculty research assistant working at the Horn Point Laboratory in University of Maryland’s Center of Environmental Sciences (UMCES), and soon-to-be graduate student at UMCES in 2021. Imani entered the aquaculture field through internships and trainings at the Oyster Restoration Team at Chesapeake Bay Foundation (Virginia) and Virginia Institute of Marine Science’s Oyster Aquaculture Training Program (OAT), and through work as an assistant hatchery manager at Hooper Island Oyster Company (Cambridge, MD). Imani was bothered that little to no people of color held management or leadership roles in aquaculture around her. With a desire to improve recruitment and retention of women and diversity in the marine sciences, Imani became founder and president of a new non-profit organization “Minorities in Aquaculture”.

Diversity, equity, and inclusivity in the ecology and fisheries workforce promotes a rich variety of perspectives, worldviews, creativity, innovation, skills, and experiences required to tackle the  complex socio-ecological issues we face. We must create individual and systemic changes to foster a scientific community to reflect this. We acknowledge that we selected just a few trailblazers, but we encourage readers to continue honoring Black History Month year round by researching other Black scientists and activists. 

“In fisheries science, we often celebrate the biodiversity of species. That celebration, however, exists in tension with the low diversity of gender and race or ethnicity in our workforce.”

Arismendi and Penaluna 2016 

To learn more about the featured scientists experiences, research, and accomplishments visit the following sites:

Dr. Roger Arliner Young:

Dr. Daniel Pauly:

Dr. Mamie Parker:

Dr. Sheila Styles :

Dr. Cecil Jennings:

Imani Black:

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