A $32-million commercial fishery has inexplicably and completely collapsed this year on the B.C. coast.

The sardine seine fleet has gone home after failing to catch a single fish. And the commercial disappearance of the small schooling fish is having repercussions all the way up the food chain to threatened humpback whales.

Jim Darling, a Tofino-based whale biologist with the Pacific Wildlife Foundation, said in an interview Monday that humpbacks typically number in the hundreds near the west coast of Vancouver Island in summer. They were observed only sporadically this year, including by the commercial whale-watching industry.

“Humpbacks are telling us that something has changed,” he said. “Ocean systems are so complex, it’s really hard to know what it means. For one year, I don’t think there’s any reason to be alarmed, but there is certainly reason to be curious.”

Humpbacks instead were observed farther offshore, possibly feeding on alternative food sources such as herring, sandlance, anchovies, or krill, but not in the numbers observed near shore in recent years.

The sardine, also known as pilchard, has a uniquely fascinating history.

Sardines supported a major fishery on the B.C. coast in the mid-1920s to mid-1940s that averaged 40,000 tonnes a year.

Then the fish mysteriously disappeared — for decades — until the first one was observed again in 1992 during a federal science-based fishery at Barkley Sound on the west coast of Vancouver Island.

With the re-emergence of the sardines came the humpbacks, around 1995, becoming so numerous in coastal waters off Vancouver Island that they supplanted grey whales as the star attraction of the whale-watching industry.

Peter Schultze, a senior guide and driver with Ocean Outfitters, said humpbacks are normally found seven to 10 kilometres or closer to shore, but this year were about 18 to 32 kilometres out. That meant for more travel time and fuel burned and less time with the humpbacks, if they were observed at all. “There were a lot of days where people got skunked.”

Overfishing had long been blamed for the disappearance of sardines from B.C. waters. But scientists today attribute the overriding cause to changes in ocean conditions that proved unfavourable to sardines.

B.C. started commercial fishing for sardines in 2002, and in 2013 had an allowable catch of about 25,000 tonnes, which compares with a total estimated population of 659,000 tonnes.

“This year was unexpected,” said Lisa Mijacika, a resource manager with Fisheries and Oceans Canada in Vancouver, noting fishing did take place in California and Oregon. “They are a migratory fish heavily influenced by ocean conditions.”

Scientists from Canada, the U.S., and Mexico will meet in December to try to find answers to the sardine’s movements.

There are now 50 B.C. commercial sardine licences, half held by First Nations.

The fishery normally operates from July to November, but not this year.

“They’ve given up looking, pulled the plug,” confirmed Lorne Clayton, executive-director of the Canadian Pacific Sardine Association. “It certainly was disappointing. It’s cost them time, fuel, and crew to go out and look, with no compensation.”