Rhithron Associates Inc.

Rhithron Associates Inc., a woman-owned small business and self-certified small disadvantaged business based in Missoula, Montana, provides macroinvertebrate identification, aquatic ecosystem monitoring, and freshwater ecology analysis services to federal natural-resource agencies as a prime contractor operating entirely on full-and-open contracts without set-aside designation. The vendor competes on GSA Multiple Award Schedule and smaller purchase orders across the Department of the Interior, Department of Commerce, and USDA, with no subcontractor activity and no set-aside recurrence across the prime footprint.

Rhithron's capability portfolio centers on benthic macroinvertebrate analysis, taxonomic identification of algal and aquatic biota, water-quality monitoring, aquatic habitat assessment, and invertebrate sorting and identification to support ecological restoration and monitoring programs. Representative recent work includes a $36,900 Multiple Award Schedule delivery order with the National Park Service Pacific West Region for macroinvertebrate sample processing and analysis on the Klamath Inventory and Monitoring Network (awarded September 2023); a $150 thousand purchase order from the National Oceanic and Atmospheric Administration for drift-sample analysis (awarded June 2024); a $24,750 purchase order from the Department of the Interior Pacific West Region for macroinvertebrate analysis and monitoring in Jackson County, Oregon (awarded September 2025); and an $18,050 purchase order awarded August 2026 for macroinvertebrate analysis on the same Klamath Inventory Network program with ultimate completion in August 2027.

Customer concentration sits primarily with natural-resource and environmental agencies. The top five customer components account for 71% of awards by count and 79% of combined potential value, led by the National Oceanic and Atmospheric Administration (19 awards, $489 thousand combined potential value), the U.S. Geological Survey Office of Acquisitions and Grants (18 awards, $332 thousand), and the National Park Service Pacific West Region (15 awards, $420 thousand). The GSA Federal Acquisition Service anchors the potential-value ranking with one award valued at $740 thousand, while NOAA and NPS Pacific West drive award frequency and recurring work. Rhithron places 33 task orders across the Multiple Award Schedule (MAS) and 6 across the Professional Services Schedule (PSA), with MAS carrying $605 thousand combined potential value.

Award volume has contracted significantly since the mid-2020s — three awards in 2024, one in 2025, and one in 2026 — reflecting a shift from the program's historical three-to-six-award-per-year baseline. Only one award (valued at $18 thousand) reaches ultimate completion within the next twenty-four months, presenting minimal recompete exposure in that window. The vendor's primary NAICS footprint is Environmental Consulting Services (44 awards), with secondary presence in Testing Laboratories and Services (20 awards). The Service Contract Inventory dataset reports minimal activity — 1.4 FTEs delivered via two SCI-reportable sub records in FY2025 — reflecting the vendor's small scale and the low-dollar nature of most awards, most of which fall below the SCI reporting threshold. Rhithron operates with no subcontractors and generates no documented subcontractor revenue, functioning as an owner-operated technical service provider rather than a prime aggregating subs or labor pools.

Taxonomic determinations of aquatic invertebrates; algae, periphyton, diatoms, phytoplankton, zooplankton, fish diet analyses, metric calculations; interpretive reports; statistical analysis of bio/habitat data; study design/consultation regarding sampling, analysis, and QA; field sampling.