“We have recently shifted from looking at the feeding behavior of the fish at depth and are focusing more on what’s happening on the surface,” said Feed Manager Tim O’Hara. It’s difficult to accurately interpret when fish stop eating, he added, saying that the company is now using the feed management principle that as long as the fish have enough feed to meet their growth potential, they will increase their weight at a satisfactory rate and be harvest-ready at the appropriate time.
Immediately following the merger, it was critical that all sites moved in the same direction at the same time in regards to feeding. Feed guidelines that weren’t necessarily as flexible as they had been in the past were introduced in order to provide consistency. “Now that everyone is singing from the same song sheet, since late last summer, we’ve been more able to take into consideration site variables such as environmental and staff fluctuations. This means giving back a larger degree of control over feeding to each site and becoming more flexible as circumstances dictate.
Because such a large portion of a site’s operating cost is feed, it’s crucial to ensure that every pellet finds a mouth and that every fish has plenty opportunity to “sit at the table” at each meal. With the new feeding regime, each pen is fed for a minimum of 40-45 minutes per day, at a rate that makes certain every pellet that enters the water is eaten, explained Tim. In order to accomplish this goal, a minimum feeding time and maximum rate of feed per minute was introduced. Although the improvement in feed conversion rate (FCR) is starting to flatten off, Marine Harvest continues to pursue further substitution of marine proteins and oils with poultry and veggie products in feed. This will decrease the marine index (the amount of factory fish swimming in the ocean that is needed to produce a kilogram of farmed salmon).
We’re at a point where large improvements in FCR have already happened so we’re looking to feed management to further fine tune inputs to the day to day needs of our fish, commented Tim. The introduction of a feeding behavior scale that is used by all sites helps with this. The key is to ensure widespread distribution of feed over the entire pen for a consistent amount of time fuelling the nutritional needs of the fish and not how much they can eat.
By Gina Forsyth