Do microplastics increase disease susceptibility in steelhead trout?

Two small fish are shown side by side in a clear container of water.

Virginia Institute of Marine Science and partners will examine whether microplastic ingestion increases disease susceptibility in steelhead trout.

Type of Project: Research

Region: Mid-Atlantic

Project Dates: August 2019 - July 2021

Who is involved?
With the support of a NOAA Marine Debris Program Research Grant, researchers from the Virginia Institute of Marine Science, The College of William and Mary, and with assistance from the Gulf of Alaska Keeper, will conduct laboratory experiments to examine the relationship between microplastics and disease susceptibility in steelhead trout. 

What is the project and why is it important?
In the environment, animals may be exposed to many stressors at the same time, such as pollution, overfishing, disease, etc. Research suggests that animals exposed to microplastics and microfibers may experience negative impacts to their immune system. Thus, to better understand how microplastics are impacting animals, we should consider the relationship between microplastic ingestion and exposure to these other stressors. In situations where an animal ingests microplastics, their immune system may be compromised and thus be less capable of dealing with additional stress, such as viral infection.  

This project will examine whether microplastic ingestion influences disease susceptibility in Pacific Northwest steelhead trout. Steelhead trout are prone to disease, including the Infectious Hematopoietic Necrosis Virus (IHNV), especially when these fish are reared in close proximity to one another in large numbers, such as in aquaculture farms. In the lab, steelhead trout will be raised from eggs, and kidney immune cells (from the fish) will be exposed to three sizes of microplastics. Researchers will observe the immune system response by these cells after exposure. Polystyrene and nylon, two types of plastic, are the likely forms of microplastics encountered by fish in aquaculture farms and researchers will use these types of microplastics for this study. The project will measure fish mortality in response to various microplastic concentrations, microplastics combined with the IHNV virus, and a control where fish are exposed to natural cotton fibers. This study will advance the state of marine debris research and help us better understand the links between microplastics, fish health, and disease.