Fish around the world are in trouble. The changing temperatures of water are changing how they live, where they want to live, and even their migration and mating patterns. The sockeye salmon are hit hard by rising water temperatures, dams that make spawning difficult, and overfishing. In fact, fishing of the sockeye salmon has become heavily restricted because the numbers are down.

In Idaho, the sockeye salmon have begun to return to the river after their numbers went down below 100- but this is only after aggressive efforts by local authorities and wildlife activists to help them get around dams and protect them through the now fragile mating season and spawning run.

The salmon of Canada, though, may be facing an adversary that cannot be circumvented the way dams are: rising water temperatures. Just as humans are wondering what we will do about a warmer environment and climactic changes in the weather patterns, fish are dealing with similar issues in their “air-“ water. And at first glance, “dealing with” means not doing well.

One expert from the University of British Columbia warned in the 1990’s that there would be lower numbers when the sea-surface temperatures rose- and it is possible that that prediction is now coming true.

“It was some of the first work ever of that kind, and nobody's really followed up,” said UBC professor Scott Hinch.

Salmon numbers in the Fraser River are down 80% this year and Hinch believes it’s due to the hottest summer on record. He published a paper in 1995 stating that warmer sea temperatures could impede the growth of plankton, leading to fewer salmon that feed on the plankton.

“Assuming that growth rate is related to survivorship in the ocean, and it should be, then, yeah, it suggested that fewer adults may come back and they would be smaller,” Hinch said. “And it also carried the logic further out of the ocean into the river and said that smaller adults, those with lower energy, should have a more difficult time completing the river migration.”

Other experts have said that while juvenile numbers leaving area lake systems are normal, their arrival rates at spawning waters are low, implicating the ocean travel and supporting Hinch’s theory.

Is warming water truly the cause of lower salmon numbers, though? Or is it, as many who are close to rivers up and down the west coast, more an issue of the salmon farms and other obstructions- like the dams that the salmon in Idaho have to maneuver around or through?

Many in Alaska seem to say that the rivers without fish farms have returning fish numbers that are just fine, even during the warmest summer on record. The rivers that are in trouble, they say, are the ones where returning salmon have to deal with the fish farms.

The point is the fish are in trouble- real trouble: fish farms, warmer water temperatures, dams and overfishing all contribute to lower survival rates. Just as the scientists can identify rising temperatures as a factor to lower plankton growth which leads to fewer salmon in the river, you can trace that back even further to all of the causes related to causing climate change in the first place. In one sense fish farming is a necessity now if the natural numbers are not coming back- but at the same time it may be causing a faster decline.