Students who serve themselves a horseradish-crusted wild salmon sandwich at lunch in a residential college dining hall on Friday may not realize just how “wild” the dish is.

A single delivery of 30,000 pounds of sustainably fished salmon from an Alaskan fishery back in the fall has provided all the salmon served in dining halls since then. The purchase also provided the secret ingredient for Wednesday night’s Iron Chef competition, which was sponsored in part by the Alaska Seafood Marketing Institute, said Regenia Phillips, director of residential operations for Yale Dining.

The salmon was professionally frozen within 24 hours of its being caught, said Gerry Remer, assistant director of sustainability and supply management for Yale Dining. Remer said that this process ensures that the salmon will stay fresh for “considerably longer” than a year. But, she noted, Yale Dining projects the entire purchase will be consumed well within a year. At that time, she added, Yale Dining will make a similar purchase of more salmon.

Yale Dining is accustomed to purchasing its food supplies, even sustainable options, in bulk. But since the expansion of Yale Dining’s sustainable options in 2006, dining administrators have been investigating new ways to serve sustainable options year round. This includes looking for new ways to preserve seasonal foods, such as vegetables grown in Connecticut, Remer said.

Yale Dining decided to purchase the salmon after recognizing the popularity of salmon dishes in Yale’s dining halls, Remer said. She added that Yale Dining received a discount for the salmon by buying in bulk.

“We’ve always found salmon to be a successful menu item,” Remer said.

Phillips credited the purchases to Rafi Taherian, executive director of Yale Dining. Phillips said Taherian is currently pursuing purchasing a large order of cod, also from Alaska. The cod is on the current Monterey Bay Aquarium’s Seafood Watch list, which names the year’s most sustainable seafood options.

According to the Monterey Bay Aquarium, sustainable fishing practices ensure that fish populations are not destroyed and natural food chains are not disrupted. For wild seafood, sustainable fishing requires that overfished species are not consumed. On the other hand, farming fish is sustainable when certain practices are undertaken to prevent habitat damage, to contain non-native fish and to provide sustainable fish feed.

Seven of 11 students interviewed praised Yale Dining for providing high quality fish throughout the year.

Elizabeth Roberts ’12 said she would not have guessed that this year’s salmon came from one bulk shipment. She said she appreciated Dining’s efforts to maintain sustainability with only a little loss of quality.

But three students interviewed said they had seen a drop in quality through the year.

“The quality has deteriorated over the past year,” Steve Gonzales ’10 said, adding that he noticed salmon has been served more frequently this year than in the past.

Still, Gonzales said he recognized the need to freeze a bulk purchase of fish because there is no other realistic way to preserve it.

Lorraine Abdulahad contribued reporting.