The goal of this research was to better understand how climate change will affect fishes with different life histories and habitat associations across the San Francisco Estuary. Existing datasets were incorporated in synthetic analyses and cutting-edge statistical models to identify fish community responses to climate, flows, and habitats along the estuarine salinity gradient. This synthesis-science project used rich long-term datasets that have been collected by Bay-Delta researchers for decades in a reproducible and open science framework.
The team investigated how freshwater flow and sea surface temperature impacted juvenile fish species in the lower and upper estuaries and found differing tolerances. Additionally, they looked at both the biological and spatial structures within the communities and concluded preserving diversity is key to stabilizing juvenile fish recruitment in response to changing environmental conditions. Even in highly dynamic environments such as estuaries, climate change will likely result in winners and losers among species. With an increase in the frequency and duration of drought and marine heatwaves, estuaries may become less hospitable to species that are environmental specialists, such as freshwater or cool water dependent species. This may lead to lower recruitment success. Ultimately, climate change may negatively affect species persistence, food web dynamics and ecosystem function.
The proposed project is driven by the need to understand how land use has changed historically in California's Central Valley due to various drivers including environmental changes and socio-economic developments. Given the region's dependency on agriculture and its vulnerability to climate change—marked by shifts in precipitation patterns and water availability—it's crucial to model these dynamics accurately to forecast future conditions and plan effectively. Using Agent-Based Modeling (ABM) provides a sophisticated means to dissect past interactions between land use and environmental factors at a granular level. This historical understanding is pivotal as it sets the stage for projecting future scenarios. Additionally, the integration of future hydrology data generated from the CalSim3 model and socio-economic scenarios allows for a comprehensive analysis of potential future states. This analysis aims to explore strategic land use modifications that can meet future socio-economic goals under varying water availability scenarios.
This research supports several key science actions, making it highly relevant to current policy discussions. It provides actionable insights into large-scale experiments (Science Action 1C), assesses the impact of climate on ecosystems (Science Action 6A), and explores water allocation strategies (Science Action 6E), thereby equipping policymakers and stakeholders with the necessary tools for informed decision-making. These decisions are crucial for maintaining ecological flows and ensuring the longterm viability of both the agricultural sector and the natural ecosystems upon which they depend.
SacPAS serves to provide information integration services to the Central Valley Project Improvement Act and practitioners working on matters related to ESA-listed fishes. The web-based services relate fish passage to environmental conditions and provide resources for evaluating the effects of river management and environmental conditions on salmon passage and survival.
The work performed as part of this agreement includes developing, maintaining, and making accessible query tools and decision support tools to access: historical, real-time and forecasted data; data summaries and visualizations; and hindcasts, forecasts, and scenario-derived predictions from statistical and mechanistic models. More specifically, the objectives are to:
1) Maintain and extend a secondary data repository of historical, real-time, and forecasted fish, environmental, and operational data from the Sacramento River and other river systems in the Central Valley, integrated from primary, public databases.
2) Maintain and improve the data query and visualization tools and services provided through the SacPAS website (https://www.cbr.washington.edu/sacramento/) for historical, real-time, and forecasted environmental and fish data.
3) Conduct research and provide access to modeling tools for fish survival and migration, through the SacPAS website, in support of Reclamation-funded and ESA-mandated activities, especially in efforts to predict, track, and evaluate the efficacy of proposed or actual actions.
