Assessing the Risk of Interstate Imports, Aquaculture and Stress to Amplify Virus Diversity and Prevalence in Maryland Blue Crabs

Principal Investigator:

Eric Schott

Start/End Year:

2022 - 2024


Institute of Marine and Environmental Technology, University System of Maryland

Co-Principal Investigator:

Tsvetan Bachvaroff, Institute of Marine & Env. Tech., UMCES; Mingli Zhao, Institute of Marine & Env. Tech., University of Maryland Baltimore County


Strategic focus area:

Sustainable fisheries and aquaculture


Rationale: Blue crab harvests and populations are highly variable in Maryland. Viral disease is a possible cause of blue crab mortalities, but  little is known about viruses in crabs. Interstate transport of blue crabs may introduce new viruses into the bay.

  • Objective 1. Identify new viruses in blue crab with metagenomic sequencing:   a. viruses in Chesapeake Bay blue crabs that die in soft-shell  production; b. viruses in imported blue crabs that die during transportation.
  • Objective 2. Investigate the prevalence of viruses in blue crab populations. a. Conduct a complete survey to investigate the prevalence of known and newly identified virus in Chesapeake Bay blue crabs. b. Conduct a  survey to quantify these virus prevalence and intensity in blue crabs that are being imported into the Chesapeake Bay from states in the Gulf of Mexico or Florida Atlantic coast.
  • Objective 3. Test the pathogenicity of newly identified  viruses
  • Objective 4. Outreach to managers, scientists, and industry participants:
    • Communicate with scientists and industry at a national conference;
    • Communicate with blue crab modelers and managers;
    • Communicate with fishermen about safe methods of discarding dead crabs.

Methods: Metagenomics of both RNA and DNA will be used to discover virus genomes in collected crabs. PCR-based tools verify and investigate prevalence. Experimental injections will assess pathogenicity of viruses.

Value to constituents: Managers need to understand causes of crab mortality. Biosecurity in transport and aquaculture is not being addressed by managers.
Outreach: The outreach plan is intended to reach managers and industry practitioners using two main strategies: 1) Presentation to the Chesapeake Bay Stock Assessment Committee and other management bodies.
2) Organize a session for the National Shellfisheries Association meeting on biosecurity of crab transportation and discards. 3) Work with Louisiana Sea Grant on printed outreach to discourage in-water discards."

The Blue Crab: Callinectes Sapidus

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pile of cooked crabs