Fish are inclined to oxidation; one must take utmost care after catching them from the ocean. All these factors revolve around the manufacturing process, because that could be the place where quality can be compromised.
Most commercial farmers use a sample on hand, look at its ends up close. https://pressadvantage.com/story/68635-veteran-owned-garage-door-grunts-ramps-up-emergency-door-repair-services-in-phoenix