A new $1.5 million research initiative led by Washington State University (WSU) could soon deliver major productivity gains for U.S. rainbow trout producers while offering simpler, more reliable environmental safeguards.

Funded by a Foundation for Food & Agriculture Research (FFAR) Growing Impact Award with matching support from WSU and commercial egg supplier Troutlodge, the project focuses on developing practical, biologically driven sterility solutions tailored for commercial hatcheries and grow-out operations.

For USTFA members, reliable sterility translates directly to improved bottom lines and smoother operational management:

• Superior Energy Allocation: Because sterile fish do not expend energy on sexual maturation and gonadal development, more feed energy goes directly into muscle mass – improving growth rates and feed conversion ratios (FCR).
• Guaranteed Biosecurity & Compliance: Biologically sterile stock eliminates the risk of escaped farm fish interbreeding with wild populations, protecting native ecosystems and easing regulatory hurdles around wild-stock interaction.

Moving Beyond Traditional Triploidy

While triploidy (induced via pressure or temperature shocks) has historically been the primary tool for producing sterile trout, it is not always 100% effective and can sometimes compromise fish health, thermal tolerance, or survival rates under farm conditions.

Led by Associate Professor Michael Phelps in WSU’s Department of Animal Sciences, this research takes a different path by leveraging trout’s natural biology to control fertility across generations.

The research team is testing two scalable breeding approaches:

• Inherited Female Sterility: Utilizing specially developed male broodstock that consistently pass down a trait rendering all female offspring sterile.
• Germ-Cell Suppressed Lineages: Breeding female broodstock whose eggs naturally produce offspring incapable of forming functional sperm or eggs.

Commercial Scaling & Next Steps

After verifying health, fertility control, and growth traits over several generations at WSU’s Pullman facilities, top-performing lines will move into field-scale commercial trials in partnership with Troutlodge.

With domestic seafood demand continuing to outstrip supply – the U.S. imported 7.4 billion pounds of seafood in 2023 – advancements in broodstock science help ensure American trout farmers remain competitive, sustainable, and productive.

Read the complete release at WSU CAHNRS News.