Blue-green algae can cause off-flavors in farmed catfish, leading to costly harvesting delays. How can these off-flavors be eliminated? Recently USDA and HeroX launched a challenge to protect the natural flavor of catfish. Winning Solutions will Share a $60,000 Prize Purse.
Exposure to certain varieties of blue-green algae, also known as cyanobacteria, can cause undesirable changes to the flavor of farmed catfish. This off-flavor delays the harvest for roughly 50% of catfish ponds each year in the United States.
Annually, this delay alone can cost catfish farmers millions of dollars in lost revenue and expenses to maintain the fish until flavor quality returns.
USDA-ARS scientists, as well as industry experts, have worked for decades to find new solutions for this problem. While methods to combat off-flavor in catfish have been identified, they are only partial solutions, requiring repeated treatments to reduce off-flavor occurrence, and providing no guarantee of successfully eliminating off flavors.
“In the United States, nearly 400 million pounds of farm-raised Channel and Blue catfish are harvested annually, primarily in the Mississippi delta region. Prior to harvesting, sample fish are captured and tested to ensure high quality.”
One of the most important evaluations performed is taste. Professional food tasters briefly cook the fish in a microwave and taste it, without seasoning or other preparations, in order to evaluate the innate flavor of the fish.
Unfortunately, exposure to compounds from varieties of blue-green algae, or cyanobacteria, can cause unpleasant tastes in catfish, described by taste testers as “earthy” or “muddy”.
If a sample fish is found to have these off-flavors, there are several options. The pond can be left alone and fish retested after several months to see if flavor has improved, or the pond water must be treated to remove these algae before harvesting can proceed.
“Treatments can take weeks to months before they are fully effective at removing the off-flavor from the fish. Both approaches result in lengthy and costly harvest delays.”
Research has identified several effective methods for treating affected catfish ponds but these methods are generally not implemented until an off-flavor fish is found. One potential method is to relocate the entire school of catfish to a new pond with water uncontaminated by blue-green algae.
The downside to this, apart from the additional cost to the farmer, is the additional stress placed on the fish – stress which itself can impact the flavor and texture quality of the harvested fish. Another treatment method is the application of algicides like copper sulfate or diuron to the affected pond water.
“While effective, public perception of additional chemical usage can limit deployment, as can the potential for unintended consequences for the overall pond ecology.”
A Global Aquaculture Alliance article estimates that US catfish farmers lose as much as $47M a year due to off-flavors. Since additional costs caused by off-flavor can account for as much as 17% of total production costs, the development of new tools to help catfish farmers maintain the natural flavor of the catfish is critical.
Competition guidelines
USDA-ARS, working in conjunction with the farmed catfish industry, has researched this topic extensively and believes that input and insight from the global innovation community can positively impact this persistent problem.
USDA-ARS has identified three different points in the process where new methods or technologies could be implemented to address off-flavors in catfish:
• Pre-harvest management practices: new methods/technologies that work to prevent the development of off-flavor causing blue-green algae in catfish ponds
• Pre-harvest treatment technologies: new methods/technologies to remove off-flavor from catfish once it has been detected in sampled fish prior to harvest
• Post-harvest treatment technologies: new methods/technologies that would allow processors to remove off-flavors from catfish after harvesting
Ideally, proposed approaches will meet the following performance criteria:
• Reduce or mask off-flavor compounds to a level undetectable to professional flavor testers (~100ng/kg)
• Cost the same or less than current treatments (currently ~$177/acre-ft, which translates to ~$8000 per pond. The average catfish pond is a 10-acre pond, 4 ft deep)
• Maintain catfish well-being
• Be neutrally or positively viewed by consumers
• Environmentally safe for both pond and surrounding areas
• Safe for operators and other personnel
USDA-ARS believes that exciting new technologies and innovations are possible and welcomes the global community to provide insight in all forms to this topic, regardless of approach.
Prizes
ARS will award up to $60,000, to be split among the top-scoring and eligible submissions, with at least one prize winner in each category. Each prize awarded will be up to $30,000 and no less than $5,000.
• Category 1: Pre-Harvest Management Practices
• Category 2: Pre-Harvest Treatment Technologies
• Category 3: Post-Harvest Treatment Technologies
Furthermore, it is the intention of ARS to facilitate the implementation of new technologies in the field to the benefit of the industry.
To that end, ARS will consider postchallenge discussions between ARS scientists and winners, engaging with winners in joint publication efforts or in collaborative work to further develop proposed technologies. The USDA-ARS Office of Technology Transfer will assist with cooperative research agreement options as warranted.
Timeline
Submission deadline December 15, 2020 @ 5pm ET
Judging December 15, 2020 – February 23, 2021 Winners Announced March 2, 2021
To qualify for an award, your proposal must, at a minimum:
• Prevent, eliminate, or mask off-flavor in farmed catfish
• Have supporting data, or a strong scientific rationale
• Be safe for the fish, the environment, and users
All rules for this contest, as well as participation eligibility criteria, and the platform for registration and submission of participations are available at the website: https://www.herox.com/catfish
