California WaterBlog

By Rachael E. Ryan, Cho R. Adolfo, Emily K. Chen, Stephanie M. Carlson

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California’s “Uncommon” Salmonid

Amidst the decline of California’s salmonid populations is an unexpected uptick of pink salmon. In recent years, biologists monitoring California waterways have been reporting sightings of pink salmon. We became curious about these observations; were they simply a result of more intensive monitoring and information sharing, or did they reflect a real increase in pink salmon occurrence in California? After doing some extensive digging into the mystery, we recently published our findings in Transactions of the American Fisheries Society (Adolfo et al. 2026).

Due to their sporadic and sparse nature in California, no formal monitoring practices exist for pink salmon across the Golden State. However, scattered pink salmon observations in California have occurred throughout history. While Washington represents the southernmost location for significant self-sustaining populations, accounts place pink salmon as far south as La Jolla in the ocean (Hubbs 1946) and, in California, as far north as the McCloud River in the 19th century (USFC 1894). Many of the early observations we encountered came from pink salmon caught in fisheries, such as inland Sacramento River fisheries (Jordan and Evermann 1896) and coastal fisheries in Humboldt County (Collins 1892). Because pink salmon appeared consistently, though in low numbers, in the Sacramento River fisheries, they earned the nickname the “lost salmon”, reflecting the mystery of provenance (Jordan and Evermann 1896). Previous reviews summarized many of these historical observations and suggested that pink salmon may once have persisted in small, intermittent runs across the state (Skiles et al. 2013; Moyle et al. 2008). Regular observations of pink salmon in a few California rivers in recent years suggested that an update on their status and trends was in order. 

Thus, we compiled a state-wide database of pink salmon observations. We surveyed monitoring programs, conducted online searches, and reached out to fish biologists monitoring salmon across California. We had a tremendous response from field biologists who enthusiastically shared their observations of pink salmon from recent surveys. More generally, we uncovered a treasure trove of pink salmon records in California found in blog photos, monitoring notes, and even email chains amongst biologists surveying California rivers (Figure 1). We also received reports of chum salmon, another uncommon salmonid species in California suggesting avenues for future work on rare salmonids in California. 

Overall, pink salmon were detected in small coastal streams to large tributaries in the Central Valley (Figures 2 and 3), including regularly in a small handful of systems (e.g., Redwood Creek, Figure 3). They were more often detected in odd years but encountered in even years too, with detections mainly consisting of adults, though a few cases observed fry (suggesting successful reproduction, Figure 3). In no case was the monitoring program designed with pink salmon in mind, suggesting the compiled observations underrepresent the occurrence of pink salmon in California waterways. 

Pink Salmon Are Increasing in California

To test whether observations of pink salmon have increased through time and across watersheds, we standardized sightings by survey effort using information from monitoring programs. We then identified 18 California watersheds with sufficiently consistent records to evaluate trends in adult pink salmon sightings between 1996 and 2023 and found that sightings increased significantly over time.

We then asked a series of follow-up questions: Are pink salmon more likely to be observed in northern watersheds, which are closer to major populations in the north, such as in Washington and British Columbia, or are they tied to broader increases in pink salmon abundance across the Pacific Ocean? Are pink salmon more likely to be observed in larger or smaller watersheds? Are salmon monitoring programs that start later in the fall less likely to detect pink salmon due to a phenology mismatch (e.g., more likely to miss the window that pink salmon are present)? 

While latitude or watershed size were not significant predictors, monitoring programs that began earlier in the season when pink salmon are more likely to be spawning (i.e., late summer/early fall) were more likely to encounter pink salmon. We also found that sightings in California tracked overall pink salmon abundance across the North Pacific; in years when pink salmon populations surged across the Pacific, sightings in California tended to increase as well, suggesting these observations reflect broader Pacific-wide population dynamics.

Is the Future Pink?

Pink salmon abundances are exploding globally, particularly at their northern edge and where they have been introduced outside their native range (Ruggerone and Irvine 2018). The apparent increase in pink salmon sightings in California is particularly striking given the widespread declines of other salmonids across the state. Why might pink salmon be responding differently? One answer may be that they are less reliant on freshwater habitats, which have been widely degraded, than many other species of salmon and trout. Pink salmon often breed in lower stretches of river systems and their offspring migrate to the ocean quickly after emergence, in some cases days or weeks after they emerge from the nest. Moreover, they have a short, two-year life cycle in their native range and are often assumed to stray at a higher rate than other salmonids, allowing them to adapt more rapidly to change. For example, recent observations suggest they are dispersing more regularly into Arctic waters as warming ocean temperatures and melting sea ice open previously inaccessible habitat (e.g., Dunmall et al. 2024). Whether pink salmon are establishing more persistent populations in California remains unclear, but their growing presence raises interesting questions about which species are most likely to adapt to rapidly changing environmental conditions, and whether the future may indeed be pink (Breda 2026).

Keep Your Eyes Open!

A key takeaway of our study is the importance of monitoring rare species to better detect ecological changes and understand the causes and consequences of their presence. California already has extensive monitoring programs for salmonids, creating an excellent opportunity to also document less common, non-target species like pink and chum salmon. Developing a centralized system for reporting and compiling sightings could help extend and strengthen the time series we began in our study, but until then, our survey is still open for responses! Find it here: Pink Salmon Sightings in California.

About the Authors

Rachael E. Ryan is a postdoctoral researcher at the Center for Watershed Sciences at UC Davis studying ecology of endangered salmon. 

Cho R. Adolfo is a Staff Research Associate in the Department of Environmental Science, Policy and Management at UC Berkeley, synthesizing salmonid species trends and ecological recovery objectives in partnership with CalTrout.

Emily K. Chen is a research scientist at CalTrout evaluating the status of California salmonids and studying salmon population dynamics to inform their management and conservation

Stephanie M. Carlson is a Professor and A.S. Leopold Chair in Wildlife Biology in the Department of Environmental Science, Policy and Management at UC Berkeley.

Further Readings

Adolfo, C. R., Chen, E. K., Ryan, R. E., & Carlson, S. M. (2026). Pink Salmon sightings are increasing at their southern edge in California, Transactions of the American Fisheries Society, vnag013, https://doi.org/10.1093/tafafs/vnag013    

Breda, I. (2026, March 15). Why this salmon species, unlike others, is booming in the Northwest. The Seattle Times

Collins, J. W. (1892). Report on the fisheries of the Pacific Coast of the United States. Report of the Commissioner for 1888. Appendix, page 3-269. United States Commission of Fish and Fisheries, Washington, D.C., USA. 

Dunmall, K. M., Langan, J. A., Cunningham, C. J., Reist, J. D., & Melling, H. (2024). Pacific salmon in the Canadian Arctic highlight a range-expansion pathway for sub-Arctic fishes. Global Change Biology, 30, Article e17353. 10.1111/gcb.17353 

Hubbs, C. L. (1946). Wandering of Pink Salmon and other salmonid fishes into southern California. California Fish and Game, 32, 81–86. 

Jordan, D. S., & Evermann, B. W. (1896). The fishes of North and Middle America: A descriptive catalogue of the species of fish-like vertebrates found in North America, north of the Isthmus of Panama, part 1. Smithsonian Institution. 

Moyle, P. B., Israel, J. A., & Purdy, S. E. (2008). Salmon, steelhead, and trout in California: Status of an emblemantic fauna. Center for Watershed Sciences, University of California Davis. 

Ruggerone, G. T., & Irvine, J. R. (2018). Numbers and biomass of natural- and hatchery-origin Pink Salmon, Chum Salmon, and Sockeye Salmon in the North Pacific Ocean, 1925–2015. Marine and Coastal Fisheries: Dynamics, Management, and Ecosystem Science, 10,152–168.10.1002/mcf2.10023

Skiles, T. D., Yoshiyama, R., & Moyle, P. B. (2013). Pink Salmon (Oncorhynchus gorbuscha) in the Salinas River California: New record and historical perspectives. California Fish and Game, 99, 55–59. 

USFC (United States Fish Commission). (1894). Report of the Commissioner for the year ending June 30, 1892. United States Commission of Fish and Fisheries, Washington, D.C., USA.