Partners seek 100% sterility with novel fish egg treatment

United States-based fish genetics services provider the Centre of Aquaculture Technologies (CAT) is seeking to advanced and commercialise a new way of inducing sterility in salmon and other species.

CAT, located in San Diego, has signed a licensing agreement with the University of Maryland, Baltimore County (UMBC) covering two of the university’s patents related to the use of Morpholinos to induce sterility in fish eggs through bath immersion.

Morpholinos are synthetic, modified nucleic acid strands used in molecular biology to block gene expression, and have been used by UMBC scientists Ten-Tsao Wong and Yonathan Zohar to develop a patented method of inducing sterility in eggs from aquatic animals.

Improved efficiency

CAT chief executive Dr John Buchanan said the deal will enable the company “to bring further pioneering sterility technology closer to commercial reality, supporting healthier fish, stronger ecosystems, and more efficient production systems”.

In a press release, CAT said there are many reasons to produce animals that do not undergo sexual maturation, including improved performance, addressing regulatory concerns about introgression between wild fish and fish that escape from farms, and reducing stress and aggression associated with sexual maturation.

“We are pleased to be working with CAT to advance the development of sterility technology in aquaculture,” said Zohar, professor at UMBC and chair of the Department of Marine Biology at the University System of Maryland's Institute of Marine and Environmental Technology (IMET).

“This collaboration, including a sponsored research agreement, aims to improve sterility success rates in Atlantic salmon, with potential applications across all finfish species. Our partnership with CAT will enable us to achieve 100% sterility and bring this technology to the aquaculture industry.”

Approved for humans

Wong, associate professor at IMET, said: “Morpholinos have been approved by the FDA (US Food and Drug Administration) for human medicine and are being used to treat Duchenne muscular dystrophy (DMD). This new agreement with CAT can accelerate our efforts to expand this technology to produce sterile fish. We look forward to collaborating with CAT to bring this technology to market.”

Morpholino sterility induction silences genes critical for germ cell development in fish embryos through bath immersion.

The fish grow normally but are sterile, avoiding the negative effects of early sexual maturation on growth, flesh quality, and survival.

Unlike other methods like triploidy, the approach is said to preserve high-performance genetics while addressing animal welfare concerns.

A flexible alternative

CAT’s Buchanan said Morpholino technology complemented the company’s genome editing solutions for sterility by offering a quick and flexible alternative.

“It can be used in situations where sterility is urgently needed, and while the introduction of sterility through genome editing into a breeding population is still in progress,” said the CEO.

“For example, in salmonids, where breeding cycles are longer, this technology provides a timely option. Additionally, our Morpholino technology will be made available in situations where genome editing is not being used. Sterility is a critical issue for the aquaculture industry, and this gives us another reliable tool that we can call on.”