As part of the San Francisco Estuary RMP 2025 Summer Cruise monitoring, Pacific EcoRisk (PER) was contracted to perform evaluations of the chronic toxicity of ambient waters collected from the San Francisco Estuary system in August and September of 2025. These evaluations consisted of the performance of the US EPA chronic (7-day) survival and growth test with the mysid shrimp Americamysis bahia. In order to assess the sensitivity of the test organisms to toxicant stress, a reference toxicant test was performed. This report describes the performance and results of these tests.