As legal and policy battles unfolded over water allocation to farmers in the Klamath Basin, one narrative from the expert marine biologists came front and center over the past four years: that marine biologists’ opinions are that Klamath Reclamation Project farmers in Southern Oregon are jeopardizing the survival of the Southern Resident Killer Whales (SRKWs). But what does the best available science say?

Let’s walk through the facts, backed by peer-reviewed research, migration data, and government documentation.

🐋 Who Are the SRKWs?

The SRKWs are an endangered population of 74 individual orcas spread across three pods: J, K, and L.

Only the K and L Pods (33 individuals) forage seasonally near the mouth of the Klamath River. J Pod remains in northern waters, primarily in the Salish Sea, and has virtually no dietary connection to salmon runs from the Klamath or Trinity Rivers (Hanson et al., 2021).

🍽️ What Do SRKWs Eat?

Southern Residents rely almost exclusively on Chinook salmon, with a preference for large, older adults (ages 4–5). According to Ford et al. (2021), only 2.2–2.3% of their total diet comes from the entire Klamath Basin—a region including both mainstem Klamath River and Trinity River Chinook stocks.

📊 Diet Breakdown: Klamath vs. Trinity Chinook

No peer-reviewed study has separated Trinity River Chinook from Klamath River Chinook in the orcas’ diet, but we can draw informed estimates based on timing and hatchery output:

• Fall-run Trinity Chinook peak in mid to late September, aligning with the SRKW fall coastal foraging period.

• Mainstem Klamath Chinook tend to run earlier, peaking in August–early September, often before SRKW presence increases.

• Trinity River fisheries contribute up to 40–50% of the Klamath Basin fall-run Chinook.

📈 Estimated Dietary Contribution (from Klamath Basin’s 2.5% total):

• Trinity River Chinook: ~1.3–1.8%

• Mainstem Klamath Chinook: ~0.7–1.2%

Assuming ~10 Full Size Adult Chinook per whale are eaten per day:

• 33 whales × 3,650 fish/year = ~120,450 Chinook

• 2.2% = ~2,650 fish/year from Klamath Basin

• Of that, an estimated 1,600–1,850 from Trinity River (not affected by the Klamath Reclamation Project), with only 800–1,000 from Klamath River affected by the Klamath Reclamation Project.

🚫 Does J Pod Eat Any Klamath Salmon?

No. J Pod’s territory is entirely north of the Columbia River, and genetic studies confirm their diet consists almost exclusively of Fraser River and Puget Sound Chinook stocks (Ford et al., 2021). That means:

Estimated Klamath/Trinity contribution to J Pod diet: ~0%

🧊 Where Are the ESA Listed Threatened Coho?

The policy debate began in 1997 involving the newly threatened SONCC coho salmon (Southern Oregon/Northern California Coast DPS). Are they at risk from water diversions by the Klamath Reclamation Project farmers?

According to Lestelle (2022):

• In summer (including August), juvenile coho do not rear in the mainstem Klamath River.

• They are found in cold tributaries (e.g., Scott, Shasta, and Salmon Rivers) and off-channel habitats such as beaver ponds and spring-fed wetlands.

• The mainstem exceeds 22°C in summer—often beyond coho thermal tolerance.

This means coho presence in the upper Klamath mainstem waters is negligible during critical irrigation months.

🧭 Review & Rebuttal: NMFS 2024 Biological Opinion on Klamath Project Operations

Date: November 2024
Author: Klamath Irrigation District Science Review Team
Subject: Scientific and Policy-Based Critique of the 2024 Biological Opinion by the National Marine Fisheries Service (NMFS) on Operations of the Klamath Reclamation Project

Executive Summary

The National Marine Fisheries Service (NMFS) issued a 2024 Biological Opinion (BiOp) concluding that the operations of the Klamath Reclamation Project may cause jeopardy to the continued existence of the Southern Resident Killer Whale (SRKW) and the Southern Oregon/Northern California Coast (SONCC) coho salmon. This determination is not supported by the best available science.

Key conclusions of the BiOp rely on flawed assumptions about:

• SRKW dietary dependence on Klamath River Chinook,

• Coho salmon presence in the mainstem Klamath River during irrigation season,

• The spatial connection between Upper Basin irrigation and oceanic whale foraging behavior,

• Hatchery mitigation obligations compensation.

This webpage provides a rigorous critique grounded in peer-reviewed science, NMFS’s own data, and hydrological facts.

🔍 1. Overstatement of SRKW Jeopardy from Klamath Basin Flows

BiOp Claim:

“Reductions in Klamath Basin Chinook abundance due to project operations may reduce prey availability for SRKWs and contribute to long-term jeopardy.” (NMFS BiOp, p. 545)

Scientific Rebuttal:

• Only ~2.2–2.3% of SRKW diet originates from the entire Klamath Basin—including both Trinity River and mainstem Klamath Chinook (Ford et al., 2021).

• J Pod (~1/3 of the SRKW population) does not forage off California at all, rendering them completely unaffected (Hanson et al., 2021).

• The NMFS BiOp does not disaggregate consumption by pod or location, despite clear geographic segregation.

• Estimated annual impact of Upper Klamath Basin flows on total SRKW prey base: <1%—well below the 10–15% prey reduction threshold linked to reproductive declines (Ford et al., 2010).

📉 Conclusion: The SRKW jeopardy finding exaggerates the ecological importance of Klamath Basin salmon and misrepresents spatial foraging realities.

🐟 2. Mischaracterization of Summer Habitat Use by Coho Salmon

BiOp Claim:

“Juvenile coho may occupy mainstem reaches during late summer and be affected by elevated temperatures from project operations.” [(NMFS BiOp, p. 519)]

Scientific Rebuttal:

• Peer-reviewed synthesis shows that SONCC coho are overwhelmingly found in tributaries and off-channel habitats during summer, not the warm mainstem (Lestelle, 2022).

• Water temperatures in the mainstem Klamath routinely exceed 22°C in August, approaching lethal limits for juvenile coho (Chesney et al., 2009).

• NMFS cites presence based on broad potential rather than verified occupancy—despite contradictory findings in their own cited literature.

📉 Conclusion: No evidence supports that mainstem Klamath habitats during peak irrigation season are critical for coho survival.

📍 3. Ignoring Geographic Disconnection Between Farmers and Ocean Whales

BiOp Claim:

“Project operations may reduce Chinook escapement and ultimately reduce prey availability to SRKW.” [(NMFS BiOp, p. 551)]

Scientific Rebuttal:

• The Klamath Reclamation Project lies over 250 miles upstream from SRKW foraging areas and well above historical salmon barriers such as Tule Lake and Lower Klamath Lake.

• NMFS fails to account for the limited-to-zero historic or present-day anadromous salmon habitat in the irrigation zone.

• Project return flows nearly equal diverted volumes, with a net effect of ~0% on summer river discharge at the mouth [(NMFS BiOp, p. 489)].

📉 Conclusion: NMFS inappropriately attributes downstream oceanic prey limitation to hydrological activity that occurs hundreds of miles from any foraging zone.

🏗️ 4. Neglecting Existing Hatchery Mitigation Obligations

BiOp Claim:

“Reduced flow and temperature may lower juvenile survival to ocean entry.” [(NMFS BiOp, p. 553)]

Scientific Rebuttal:

• Hatchery releases offset natural habitat limitations. For example:

  • Fall Creek Hatchery produces ~3.25 million fall-run Chinook annually (NOAA, 2024).

  • PacifiCorp’s FERC license requires Chinook mitigation, including 5 million fingerlings and 1 million yearlings per year (KHSA, 2022).

• Coho production, while smaller (~75,000 yearlings), is also maintained under state and federal oversight.

📉 Conclusion: NMFS overlooks long-standing mitigation mechanisms that compensate for any upstream habitat constraints.

✅ Final AI Conclusion: A BiOp Jeopardy Finding is Scientifically Unsupported

The 2024 NMFS BiOp significantly overstates the role of Upper Klamath agriculture in ESA-listed species decline and fails to incorporate geographic, genetic, and hydrologic scale into its risk assessment. This results in a policy mismatch unsupported by the best available science.

🔗 Key Documents and Sources

• NMFS 2024 Biological Opinion on Klamath Project Operations (PDF)

• Ford et al., 2021 – SRKW Diet Study

• Hanson et al., 2021 – SRKW Migration Memo

• Lestelle, 2022 – SONCC Coho Review

• KHSA Mitigation Requirements (PDF)

📚 Summary: No Biological Jeopardy from Farmers

✅ Conclusion

The idea that Upper Klamath Basin farming threatens orca survival is not supported by data.

Management actions should be based on ecological science, not perception.

Want to dig deeper?

• SRKW Diet Study – Ford et al. (2021)

• SONCC Coho Life History – Lestelle (2022)

• Hatchery Mitigation Mandate – KHSA Report

📢 Share this post to help bring facts back into the Klamath Basin water conversation.

#SRKW #KlamathBasin #WaterPolicy #ScienceBasedManagement #ChinookSalmon #CohoRecovery #ESA #Irrigation #Conservation #Hydrology #KlamathID