SORMI Assay Development

Summer Oyster Resilience & Mortality Index — a quantitative tool for improving field survival of Pacific oysters

WRAC-funded · Multi-institutional collaboration
Supported by the Western Regional Aquaculture Center (WRAC) — USDA National Institute of Food and Agriculture
About the project

Why SORMI?

Summer mortality events are a persistent, costly challenge for Pacific oyster (Crassostrea (Magallana) gigas) aquaculture across Washington, Oregon, and California. Rather than isolating a single cause of mortality, SORMI asks a different question: why do oysters survive?

We are developing a quantitative stress resilience index composed of rapid, affordable physiological assays. The index will be used by breeding programs to select for resilience and by growers to assess real-time stress in commercial stocks, enabling pre-emptive harvest decisions and reducing catastrophic losses.

Assay Development

Stress Resilience Assay Panel

Five candidate traits were selected based on established stress-response literature, low cost (<$10/sample), and compatibility with high-throughput 96-well plate formats suitable for breeding programs and on-farm evaluation.

Resazurin Metabolic Rate
Organismal metabolic rate

Non-lethal, colorimetric measure of whole-organism metabolism. Lower metabolic rate under stress and faster recovery predict field performance.

< $1.00 / sample
Na+/K+ ATPase
Cellular stress management

Transmembrane pump activity essential for osmotic regulation. Higher activity is positively associated with stress resilience.

~$2.50 / sample
Glycogen Content
Energy storage

Critical carbohydrate stores fueling metabolism and reproduction. Higher baseline glycogen and retention under stress correlate with survival.

~$5.00 / sample
Citrate Synthase
Aerobic metabolic capacity

Marker of oxidative metabolic potential. Higher activity indicates greater capacity to generate energy under stress.

~$5.70 / sample
Lactate Dehydrogenase
Anaerobic metabolic capacity

Measures anaerobic energy production when oxygen is limited. Higher LDH activity is expected to improve stress tolerance.

~$4.10 / sample
Research Objectives

Project Goals

  1. Develop the Stress Resilience Index

    Establish protocols for the physiological assay panel, characterize trait responses to acute thermal stress, and identify traits most predictive of field survival through correlation and model-selection analyses.

  2. Evaluate in POGS Breeding Families

    Apply the index to 50+ families from the USDA Pacific Oyster Genomic Selection (POGS) program deployed in Willapa Bay, WA and Tomales Bay, CA. Quantify heritability and the genetic correlation between stress resilience and market survival.

  3. Regional Community of Practice

    Engage commercial growers across WA, OR, CA, and AK through workshops, farm visits, and sample evaluation services — building capacity for data-influenced management decisions.

Open Science

Data & Protocols

All assay development data, analysis code, and protocols are shared openly. Current work includes glycogen (Glycogen-Glo), Na+/K+ ATPase, and resazurin assay optimization for M. gigas.

GitHub Repository Glycogen Assay Na/K ATPase Resazurin Assay
Investigators

Project Team

Bobbi Hudson
Lead PI
Pacific Shellfish Institute
Steven Roberts
Co-PI — Assay Development
University of Washington, SAFS
Neil Thompson
Co-PI — POGS Breeding
USDA-ARS, Pacific Shellfish Breeding Center
Mackenzie Gavery
Co-PI — Assay Development
NOAA Northwest Fisheries Science Center
Kevin Marquez Johnson
Co-PI — Extension & Outreach
Cal Poly & California Sea Grant
Louis Plough
Collaborator
USDA ARS
Sam Gurr
Collaborator
Oregon State University