Something unusual is happening off the coast of British Columbia. Fish species normally found in the warm waters of the tropics are finding their way north — and a blob is being blamed.

Ian Perry, a research scientist with the Department of Fisheries and Oceans based on Vancouver Island, says butterfish, tope sharks, ocean sunfish, even a finescale triggerfish have all been spotted further north than usual.

"The triggerfish... seemed quite happy, feeding away...Perhaps the most unusual was a louvar, which is related to the surgeonfish. It feeds on jellyfish and swims in the open water. We've never seen those in B.C. before."

Perry says it's not uncommon for some of these fish to find their way northward every five to 10 years, whenever there's an El Nino, a massive patch of warm water that appears in the Equatorial Pacific every few years.

It affects weather patterns across the world. Typically, its appearance means more rain on the Pacific coast and a milder winter east of the Rockies.

But this year, the El Nino has yet to arrive.

Riding The Blob to B.C.

Instead, Perry says, a different drifting patch of warm water off the coast of North America — known more commonly as The Blob — might be to blame.

The anomaly was first detected in 2013 by University of Washington climate scientist Nicholas Bond, who gave it the nickname "blob."

Louvar fish Luvaris imperialis

The Louvar fish, which has been seen for the first time in B.C. waters this year, can grow up to two metres long. (royalbcmuseum.bc.ca)

Since the fall of that year, scientists have been tracking a large mass of water in the Pacific Ocean that is 1,000 kilometres long and at least 2 C warmer than usual.

The blob now stretches from Mexico to Alaska and scientists say heat is being trapped within it, making it feel like home for fish used to warmer climes.

"With that comes a number of species that live within the water column," says Perry. "So they tend to go with the currents and they go wherever they're comfortable."

Perry says an El Nino event is expected in the fall, which should keep the tropical visitors around for a while longer, but they'll probably disappear when winter arrives.

"These fish don't really know where they are ... As long as the currents take them north, and the temperature is warm enough and there's food to eat, they're quite happy to live and to grow."