Julie Thayer, Ph.D.
Julie has worked in the California Current marine ecosystem for three decades, with a brief hiatus on the north coast of Brazil. She studied at the University of California at Santa Cruz/Long Marine Lab and UC Davis in Marine Biology and Ecology. Julie has conducted research on a variety of top predators (marine birds, mammals and predatory fishes) and their prey in relation to ocean climate. She has worked on forage fish population dynamics, quantified predator diet and bioenergetic consumption needs, analyzed thresholds of prey in the environment across predator taxa, and developed seabirds as indicators for various aspects of forage fish ecology. She integrates these into frameworks of ecosystem considerations for fisheries management. Recently she has become involved in predicting future abundance of commercially-important fishes off the US West Coast relative to changing ocean conditions. Julie is a Research Associate at the UC Santa Cruz Institute of Marine Science, has participated in various federal and state working groups, and collaborates regularly across a wide range of institutions.
Involvement in FI projects:
California Current Predator Diet Database - compilation of forage species in the diets of over 100 species of marine predators from 200+ scientific citations, spanning the last 100 years in various regions of the California Current Ecosystem, and feeding into ecosystem modeling
Field research: Alcatraz seabird monitoring - studies of population changes, diet, productivity, and human disturbance to Brandt’s Cormorants and Western Gulls since the early 1990s, in conjunction with the National Park Service
Forage fish populations - research on abundance and demographics (i.e., anchovy, herring), how they are used by predators (from seabirds to sharks, sea lions to salmon), and how the role of forage in marine food webs may be impacted by fisheries
Predators as indicators - developing seabird, sea lion, salmon and other predator diet as indicators of various aspects of forage fish ecology (e.g., abundance, community composition, length frequencies)
Ecosystem considerations for fisheries management - synthesizing data, developing indicators and integrating ocean and climate influences, predator-prey interactions and habitat needs into management-ready frameworks for forage fisheries (e.g., herring) as well as commercially-valuable predatory fishes (e.g., California halibut)
Marine Fisheries Climate Adaptation Plan for the Quinault Indian Nation - investigates how fisheries will be impacted by climate change along the mid outer coast of Washington State
Member of the Ocean Protection Council Science Advisory Team Microplastics Risk Assessment Working Group
Selected publications:
Thayer et al. 2021. Inter-annual variability in forage fish population size structure: Comparison of selectivity of traditional vs. non-traditional sampling devices. Fisheries Research. [pdf]
Sydeman et al. 2020. Sixty-five years of northern anchovy population studies in the southern California Current: From collapse to recovery and back. ICES Journal of Marine Science. [pdf]
Thayer et al. 2020. Ecosystem considerations for forage fisheries: San Francisco Bay herring case study. Marine Policy. [pdf]
Robinson et al. 2019. Novel vs. traditional approaches to sampling seabird diet: nest and pellet analysis of Brandt's Cormorants (Phalacrocorax penicillatus). Waterbirds. [pdf]
Thompson et al. 2019. Indicators of pelagic forage community shifts in the California Current Large Marine Ecosystem, 1998-2016. Ecological Indicators. [pdf]
Robinson et al. 2018. Changes in California sea lion diet during a period of substantial climate variability. Marine Biology. [pdf]
Sydeman et al. 2018. Forecasting herring biomass using environmental and population parameters. Fisheries Research. [pdf]
Koehn et al. 2017. Trade-offs between forage fish fisheries and their predators in the California Current. ICES Journal of Marine Science. [pdf]
Thayer et al. 2017. California anchovy population remains low, 2012-2016. CalCOFI Reports. [pdf]
Davison et al. 2017. Are there temporal or spatial gaps in recent estimates of anchovy off California? CalCOFI Reports. [pdf]
Thompson et al. 2017. Trends in Pacific herring (Clupea pallasii) in the California Current Ecosystem. CalCOFI Reports. [pdf]
Koehn et al. 2016. Developing a high taxonomic resolution food web model to assess the trophic position of forage fish and their predators of the California Current Ecosystem. Ecological Modeling. [pdf]
MacCall et al. 2016. Recent collapse of northern anchovy biomass off California. Fisheries Research. [pdf]
Szoboszlai et al. 2015. Forage species in predator diets: Synthesis of data from the California Current. Ecological Informatics. [pdf]
Thayer et al. 2014. Changes in California Chinook salmon diet over the past 50 years: relevance to the recent population crash. Marine Ecology Progress Series. [pdf]
Thayer et al. 2008. Forage fish of the Pacific Rim as revealed by diet of a piscivorous seabird: synchrony and relationships with sea surface temperature. Canadian Journal of Fisheries and Aquatic Sciences. [pdf]
Wells et al. 2008. Untangling the relationships between climate, prey, and top predators in an ocean ecosystem. Marine Ecology Progress Series. [pdf]
Thayer and Sydeman 2007. Spatial and temporal variability in diet and reproductive performance of an upper-trophic predator (Cerorhinca monocerata) relative to upwelling in the central California Current System. Marine Ecology Progress Series. [pdf]