In this action, a group of environmental organizations seek to compel Defendant County of San Luis Obispo (“Defendant”) to make changes to how it operates a dam and related infrastructure in the Arroyo Grande Creek (“AG Creek”) watershed.
Plaintiffs claimed that the County’s operations have caused significant harm to the South-Central California Coast Steelhead trout (the “Steelhead”).
The Steelhead is a protected species under the Endangered Species Act (“ESA”). At least two other ESA-listed species inhabit the AG Creek: (1) the tidewater goby (“TWG”); and (2) the California red-legged frog (“CRLF”).
Defendant has presented evidence that juvenile Steelhead are predators of the California red-legged frog (“CRLF”) larvae and the tidewater goby (“TWG”).
Mark R. Jennings, a former USFWS biologist that Defendant has retained as an expert, therefore suggested that measures to increase the AG Creek’s Steelhead population may come at the expense of its CRLF and TWG populations.
Tevin Schmitt, a Watershed Scientist that Plaintiffs offered as an expert acknowledged that the Steelhead is a meso-predator but contended there is no evidence that Steelhead predation is, or could become, a major factor affecting the AG Creek’s CRLF and TWG populations.
Defendant filed a Daubert motion challenging the declaration of Tevin Schmitt. Plaintiffs have also filed objections to the declaration of Dr. Mark R. Jennings.
Watershed Expert Witness
Tevin Schmitt holds a Bachelor of Science in Environmental Science and Resource Management with a minor in Biology from California State University (“CSU”) Channel Islands. He conducted ecological research on Southern California coastal ecosystems, petroleum toxicology research, and water quality analysis projects in the Santa Clara River watershed during his time as a research assistant for CSU Channel Islands.
Fisheries Expert Witness
Mark Russell Jennings, Ph.D earned a Bachelors degree in Fisheries and a Masters in Natural Resources (with emphasis in Fisheries) from Cal Poly Humboldt, and a Ph.D. in Wildlife and Fisheries Science from the University of Arizona. He is a versatile ecologist, with specialties in both herpetology and fisheries biology. For the past 49 years, he has worked extensively with a wide variety of fishes.
Discussion by the Court
Tevin Schmitt
In relevant part, Defendant argued that Schmitt lacked professional experience to qualify as an expert on the CRLF and TWG because he “only has an undergraduate minor in biology and no track record of research or publication on either species.”
The Court agreed that Plaintiffs have not presented sufficient evidence to show Schmitt is qualified to opine on how Plaintiffs’ requested relief would impact the CRLF and TWG.
Plaintiffs claimed that Schmitt is qualified to opine on the CRLF and TWG as an experiential expert. In support, Plaintiffs refer the Court to evidence that Schmitt has conducted nocturnal surveys, conducted habitat assessments, and collected acoustic monitoring data for the CRLF in the Santa Clara River Watershed. Plaintiffs also refer the Court to evidence that Schmitt has conducted water quality and habitat monitoring in the Santa Clara River Estuary and Ormond Lagoon to “assess habitat conditions for endangered species, like the TWG, that rely on these coastal lagoon habitats.”
However, Plaintiffs have not directed the Court to evidence, or presented sufficient argument, to explain how this experience would qualify Schmitt to opine on, among other topics, (1) whether an increase to the Steelhead population would adversely affect the AG Creek’s CRLF and TWG populations; (2) the likelihood that increasing water flows could displace CRLF and TWG eggs; (3) how that displacement would impact the CRLF and TWG’s overall population stability; and/or (4) whether the cumulative benefits of an increase in water flows to the CRLF and TWG would outweigh the potential loss of CRLF and TWG eggs.
Therefore, Plaintiffs have not met their burden to show, by a preponderance of the evidence, that Schmitt is qualified to address CRLF and TWG behavior, ecology, and population dynamics, and the Court will not consider Schmitt’s opinions on these topics.
Mark Jennings
Plaintiffs argued that Jennings has not sufficiently explained why the 2007 IDRS flow regime would be less detrimental to the CRLF and TWG than Plaintiffs’ proposed flow regime.
Plaintiffs also argued that Jennings’ opinions are unreliable because he failed to consider certain statements in the County’s 2025 Draft Habitat Conservation Plan (“HCP”) that contradict his opinions.
Based on the Court’s review of the Jennings Declaration, the Court is satisfied that Jennings has sufficiently explained why he believes Plaintiffs’ requested flow regime would harm the CRLF and the TWG. To the extent Jennings’ opinions are inconsistent with statements in the 2025 Draft HCP, Plaintiffs have not presented evidence sufficient for the Court to determine that the statements in the 2025 Draft HCP are accurate and the challenged testimony in the Jennings Declaration is inaccurate.
Held
- The Court granted the Defendant’s motion to exclude Tevin Schmitt’s proposed testimony.
- The Court overruled Plaintiffs’ objections to the declaration of Dr. Mark Jennings.
Key Takeaway
Schmitt “claims to have field experience with CRLF and species like the TWG” but this experience is insufficient for Schmitt to qualify as an expert on either species because “he does not hold the certifications that are required for him to handle, collect, or otherwise engage with these species in the wild.”
Case Details:
| Case Caption: | San Luis Obispo Coastkeeper V. County Of San Luis Obispo |
| Docket Number: | 2:24cv6854 |
| Court Name: | United States District Court, California Central |
| Order Date: | June 29, 2026 |
