California WaterBlog

by Peter Moyle

William A. Bennett (1955-2024)  was a top-notch scientist/biologist who spent much of his career improving our understanding of the ecology and management of native and non-native fishes in the SF Estuary (SFE) especially delta smelt and striped bass.  Those of us who had the good fortune to work with him knew Bill as an insightful biologist who worked hard to retain his objectivity on controversial fish management issues in the SFE.  

I got to know Bill when he joined my lab as a graduate student in Ecology at UCD in 1987. I agreed to sponsor him because I was impressed by his outstanding academic record as both a teacher and researcher at U. Mass. Boston.   Bill also spent time as a research assistant working with the famous ecologist Richard Levins, where he learned about ecological modeling and gained an appreciation for Loop models, dialectics and holistic approaches to theoretical ecology.  His first published paper (1990) dealt with competitive interactions between house sparrows and house finches, published in the prestigious journal American Naturalist.

Once his M.S. degree was in hand, Bill decided to obtain his PhD studying fish ecology in a different ocean (Pacific) than the one he grew up with (Atlantic), although both had striped bass in common.  I provided him with the opportunity to study fish in the SFE, and he took advantage of it.  He quickly became knowledgeable about the SF Estuary and its fishes.  Soon, he began working with other faculty (e.g., David Hinton) and wrote the grant that funded (including much of his salary, 1988), a study on the ecology and effects of contaminants on larval striped bass. 

An important aspect of Bill’s work in diverse laboratories was that he brought with him 20 years of working as a carpenter and machinist in Boston (1965-1986). This meant he could build and fix almost anything. Thus, in the early days (1980s) of my monthly fish sampling of Suisun Marsh, he was a key person in keeping the project afloat. For a while, it seemed the project was in its final days because of lack of funding and because my research boat was falling apart from years of abuse.  Bill stepped in and said he could restore the boat with the limited funding I had available.  I was skeptical, but he convinced me that he could do it.  The next thing I knew, he had the boat in his driveway, stripped down to its aluminum hull. A month later, the boat was on the water, so we could continue the Suisun sampling. But the outboard motor on the boat was also failing, beyond the capacity of even Bill to fix it. In desperation, I went to the Dean (Graham Gall) to beg for some emergency funding.  He was impressed with all the work had been done to keep the Suisun sampling program afloat and provided funds for a new outboard motor.  This gave the project the ‘breathing room’ it needed for me to finalize project funding.  Today, many years later, the Suisun  Marsh fish sampling program is stronger than ever. The monthly sampling is now a key component of fish sampling programs in the entire San Francisco Estuary. The Suisun Marsh fish sampling program employed and trained many students over the years, thanks to Bill.

Bill received his PhD (1993) with a dissertation as complex as the rest of his work: “Interaction of food limitation, predation, and anthropogenic intervention on larval striped bass in the San Francisco Bay estuary.”   To keep his project rolling,  he worked as a research scientist with the UCD Center for Watershed Sciences and then at the Bodega Marine Laboratory. In Bill’s words, his main research focus was “understanding the population dynamics and forces structuring fish assemblages in the San Francisco Estuary and near-shore marine environments in California.”  His first work on larval striped bass  (published in 1995) showed how water contaminated with herbicides at times was an important cause of high mortality in early life stages of pelagic SFE fishes.  Subsequently, he worked with a coalition of other scientists to determine the habitat requirements of pelagic fishes, especially the endangered delta smelt and longfin smelt, as seen in the list of selected publications below.  

These studies by Bill and colleagues at San Francisco State University and at the USGS were large multi-disciplinary field campaigns that involved virtually all the large vessels in the Interagency Ecological Program, and dozens of people from multiple agencies, all sampling continuously and simultaneously around the clock in the Suisun Bay/Confluence region.  These studies were important because persistence of pelagic fishes (e.g., delta smelt, longfin smelt, striped bass) depends on management strategies that maintain zooplankton populations.  His publication list also reveals that he played an important role in developing an understanding of zooplankton movements in relation to tides, freshwater inflow to the “Entrapment Zone”  and their availability as prey for smelt and other pelagic fishes.  He demonstrated that zooplankton populations were a critical part of the food web.  Few people understood this better than Bill because he applied a broad understanding of how the estuary worked  (or did not work) to support pelagic fishes, especially delta smelt.  His work was central to numerous project reports that were part of the CALFED Bay-Delta Ecosystem Restoration program and the Interagency Ecological Program as well as various technical reports for agencies.

Colleagues who worked closely with Bill during this time were impressed by how courageously he dealt with the intense pressure associated with his work on delta smelt during the period when the delta smelt declining population began to restrict exports of water from the Delta.   Bill often had to deal with politics associated with Endangered Species Act protections for delta smelt.   For example, Bill and a few colleagues had concerns regarding the viability of the so-called 2-Gates Fish Protection Demonstration Project.  This was an $80 million dollar project, endorsed by Senator Diane Feinstein and Governor Arnold Schwarzenegger, that aimed to increase protections for delta smelt and for water reliability.  Somehow these concerns reached David Nawi, Senior Advisor to Secretary of Interior Ken Salazar.  David set up a meeting of SFE scientists and the proponents of the 2-Gates project to discuss the scientists’ concerns. Before the meeting, Bill joked it could be their last day working in the Delta.  But no one lost their job and Bill noted that the outcome of this meeting was another large experiment designed to address concerns associated with the 2-Gates project.  The 2-Gates Project was never implemented.

Not surprisingly, Bill was frequently an invited speaker and workshop participant, where his broad knowledge of estuarine food webs and sense of humor were appreciated and valued. In fact, Bill’s talks at the annual Interagency Ecological Conference at Asilomar were legendary because his work on delta smelt invariably put him in the “hot seat”. Yet, he returned to Asilomar year after year for over a decade. Often Bill would weave in rock and roll lyrics into his seminar and paper titles (see Bennett and Burau, 2015, for an example), combining his love for estuarine science and music. He was the Principal Investigator on over 25 major grants from agencies that worked towards addressing major issues in the estuary.  His keen intellect combined with a unique perspective led to novel approaches and new insights into estuarine fish ecology.

Bill also worked in the nearshore marine environment collaborating with his wife Dr. Laura Rogers-Bennett in their laboratory at the Bodega Marine Laboratory studying sea urchins, the rockfish fishery and larval fishes. In their work together, Bill added elegant multivariate statistical analyses to help demonstrate plasticity in sea urchin morphology from different habitats and compare multiple growth models. In the nearshore rocky reefs, Bill worked to examine contrasting patterns of recreational fishing pressures in southern compared to northern California showing the influence of climate change on fishery landings. In another collaboration, Bill and Laura lived in a tiny trailer with their new baby Brian working to test the impact of inland silverside predation and turbidity on the survival of larval fishes in large mesocosm experiments in Suisun Marsh. 

In short, Bill Bennett was a highly valued member of the SFE research community, whose publications and interactions with other researchers have led to an improved understanding of the dynamics of estuarine fishes, especially endangered delta smelt.  He was also a colleague who produced influential publications, some listed below.  For example, he was a co-author (with six other scientists) of the 2010 book, produced by the Center for Watershed Sciences, on the future of the Delta.  He was asked to join the author team because of his deep knowledge of the estuary ecosystem and its fishes. For the past 10 years or so, he was an advisor on science issues for The Bay Institute. Amazingly, he was actively working on critical TBI initiatives right up to his death, including a briefing for a group of scientists on recent delta smelt modeling efforts. 

Bill Bennett is survived by his two children Brian Bennett (Dive and Boating Safety Officer), his daughter Lucy Bennett (graduate student in Landscape Architecture and Environmental Planning at UC Berkeley) and their mother Dr. Laura Rogers-Bennett. Bill’s siblings are Susan Bennett, Linda Cook and Robert Bennett and he is predeceased by his mother, Dorothy Creutz, and father Edward Bennett. Bill will be missed by his family, his colleagues, his friends and all who knew him.  A celebration of  Bill’s life is planned for June 2, at the Bodega Marine Laboratory.

Peter B. Moyle is a Distinguished Professor Emeritus at the University of California, Davis and is Associate Director of the Center for Watershed Sciences. 

Selected publications

Bennett, W.A., D.J. Ostrach, and D.E. Hinton. 1995. Condition of larval striped bass in a drought- stricken estuary: pelagic food web limitation. Ecological Applications 5: 680-692.

Rogers-Bennett, L., Bennett, W.A., Fastenau, H.C., and C.M. Dewees 1995. Spatial variation in red sea urchin reproduction and morphology: implications for harvest refugia. Ecological Applications 5:1171-1180.  

Bennett, W.A. and P. Moyle. 1996. Where have all the fishes gone?: factors producing fish declines in the San Francisco Bay Fishes. In, San Francisco Bay: the Ecosystem. J.T. Hollibaugh, editor. Pacific Division, American Association for the Advancement of Science, San Francisco, California.

Kimmerer, W.J., J. Burau, and W.A. Bennett. 1998. Tidally-oriented migration and position maintenance of zooplankton in northern San Francisco Bay. Limnology and Oceanography 43: 1697-1709. 

Kimmerer, W.J., J. Burau, and W.A. Bennett. 2002. Persistence of tidally-oriented vertical migration by zooplankton in a temperate estuary. Estuaries 25:359-371

Bennett, W.A., W.J. Kimmerer, and J.R. Burau. 2002. Plasticity in vertical migration by native and exotic estuarine fishes in a dynamic low-salinity zone. Limnology and Oceanography 47: 1496-1507.

Kimmerer, W.J., J. Burau, and W.A. Bennett. 2002. Persistence of tidally-oriented vertical migration by zooplankton in a temperate estuary. Estuaries 25:359-371

Rogers-Bennett, L., Rogers, D.W. Bennett, W.A. and T.A. Ebert. 2003. Modeling red sea urchin growth using six growth models. Fishery Bulletin 101:614-626. 

Bennett, W.A., Roinestad, K., Rogers-Bennett, L. Kaufman and B. Heneman 2004. Inverse regional responses to climate change and fishing intensity by the recreational rockfish fishery in California. Can. J. Fish. Aquat. Sci. 61:2499-2510.

Bennett, W.A. 2005. Critical assessment of the delta smelt population in the San Francisco Estuary, California. San Francisco Estuary and Watershed Science. 3(2): 71pp . (http://repositories.cdlib.org/jmie/sfews/ vol3/iss2/art1/)

Hobbs, J.A., Q. Yin, J. Burton-Hobbs, and W.A. Bennett. 2005. Retrospective determination of natal habitats for anestuarine fish with otolith strontium isotope ratios. Journal of Freshwater and Marine Research. 56: 655-660.

Hobbs, J.A. , W.A. Bennett, and J. Burton-Hobbs. 2006. Assessing nursery habitat quality for native fishes in the low-salinity zone of the San Francisco Estuary, California. Journal of Fish Biology 69: 907-922.

Hobbs, J.A., W.A. Bennett, and J. Burton-Hobbs. 2007. Modification of the biological intercept model to account forontogenetic effects in laboratory-reared delta smelt (Hypomesus transpacificus). U.S. Fishery Bulletin. 105:30-38.

Hobbs, J.A., W.A. Bennett, J. Burton-Hobbs, M. Gras. 2007. Classification of larval and adult delta smelt to nursery areas by use of trace elemental fingerprinting. Transactions of the American Fisheries Society 136:518-527

Hobbs, J.A. W.A. Bennett, and J. Burton-Hobbs. 2006. Assessing nursery habitat quality for native fishes in the low-salinity zone of the San Francisco Estuary, California. Journal of Fish Biology 69: 907-922.

Lund, J., E. Hanak, W. Fleenor, W. A. Bennett, R. Howitt, J. Mount, and P. Moyle. 2010. Comparing Futures for the Sacramento-San Joaquin Delta. University of California Press, Berkeley, CA.

Thomson, J., W. Kimmerer, L. Brown, K. Newman, R. MacNally, W. Bennett, F. Feyrer, and E. Fleishman. 2010.  Bayesian change-point analysis of abundance trends for pelagic fishes in the upper San Francisco Estuary. Ecological Applications 20(5): 1431-1448.

Bennett, W.A. and J. R . Burau , J.R.. 2015. Riders on the storm: selective tidal movements facilitate the spawning migration of threatened Delta Smelt in the San Francisco Estuary. Estuaries and Coasts 38:826-835.