Something about the food fishery in Newfoundland and Labrador stinks. But it doesn't stink like fish.

It's known around the province as blackberry — a stench caused by codfish eating a type of zooplankton.

"You don't even have to cut it open. You can smell it as soon as it gets in the boat," said Leo Hearn, a fisherman from Petty Harbour.

"It's a sulphur smell almost like rotten eggs and it's really bad."

The zooplankton have shells like snails, and according to Department of Fisheries and Oceans scientist Karen Dwyer, are eaten by the cod if they are available.

After devouring the zooplankton, the cod's stomach turns black. The infection then spreads to the flesh, which also turns black.

According to Hearn, fish harvesters are seeing more blackberry than ever before. He believes it is because the capelin are late rolling into shores around the province.

Dwyer is unsure if the fish are being affected at a higher rate, but did say without capelin, the cod are left to eat whatever they can find.

According to Karen Dwyer, with the Department of Fisheries and Oceans, cod are opportunistic eaters and will replace capelin in their diet with zooplankton. (Sherry Vivian/CBC)

"They are opportunistic eaters," she said. "They will eat whatever is around."

The arrival of capelin onshore varies from year to year, and varies among coves around the province.

According to an online capelin calendar, the tiny fish came into Middle Cove around the middle of July in 2015 and 2016. For the four years previous, however, the fish arrived in June.

Because of their nature as a staple fish, Hearn does not believe the capelin should be caught.

"Everything moves in with the capelin," he said. "You shouldn't be allowed to kill them, should just leave it. It's the food chain and they're interrupting the food chain."