It used to be that to win the fishing derby, only the biggest fish mattered. That’s changed this year — starting this weekend.

In a move to spur more interest in the annual sportfishing contest by making every catch a possible winner, the chamber of commerce will award $2,700 in cash prizes for the nine catches closest to hidden weights. 

There still will be prizes for the largest king salmon, coho salmon and halibut hauled in during the three-month derby, but starting this weekend there will be the additional prizes for the lucky-weight catch rather than the biggest fish on four weekends.

No one will know the weight until after the fishing closes for the weekend, when computer software will generate the hidden weight to determine the winners, explained Sylvia Ettefagh, chamber of commerce board president.

“We give it an upper and lower limit,” she said of instructions to the random-number generating software.

The winning weights will fall between 10 and 300 pounds for halibut; 5 and 15 pounds for coho salmon; and 15 pounds and higher for king salmon.

Each hidden-weight winner will be worth $300 to the derby ticket holders who pulled in the catch.

The designated weekends for the new prizes are Saturday and Sunday, June 20-21 (Father’s Day weekend), with $300 each for the king salmon and halibut closest to the weight; July 5, with prizes for the lucky king, coho and halibut; Bearfest weekend of Aug. 8-9 for coho and halibut; and Labor Day weekend of Sept. 5-7 with $300 each for a coho and halibut.

The derby started June 7 and will close Sept. 7, with the traditional prizes for the largest fish awarded after the derby closes. The cash prizes will be $1,000 each for the biggest king, coho and halibut.

Derby tickets, at $35 each, are on sale at Sentry Hardware, the Stikine Inn and the chamber office in the Nolan Center.

The weekday weigh-in station is at Peninsula Seafoods at the Marine Service Center.

Boaters who bring in catches evenings and weekends can go to a weigh-in station at Reliance Harbor, across from the harbormaster’s office, or call ahead to arrange a weigh-in 907-874-3901, 907-305-0552 or 907-305-0553.

As of Sunday, only a few fish had been entered in the derby, but Ettefagh said she is not worried about the slow start to fishing. “It will pick up.”