Warmer Temperatures in Gulf of Alaska Could Have Effects on Fisheries
Temperatures in the waters of the Gulf of Alaska have been as high as five degrees Fahrenheit above average. Although fluctuation does occur naturally with the seasons, this particular increase is attributed to other factors.
El Nino is characterized by unusually warm temperatures in the equatorial Pacific. The National Oceanic and Atmospheric Administration predicts there’s a 65 percent chance of El Nino emerging in fall and early winter.
Research fishery biology with NOAA fisheries Joe Orsi says it’s a normal and natural occurrence to see changing water temperatures.
“What goes on in the Gulf of Alaska is you have a current that comes over from japan eastward and it strikes the west coast of North America by about 45 degrees around Vancouver Island and it splits. It has a southern branch called the California current and a northern branch called the Alaska coastal current. And that moves northward and that circulates counterclockwise into the Gulf of Alaska forming the Alaska Gyre. If you have anomaly warm water that’s in the southern part of these currents, it will work its way northward and spin its way into the gulf. And that’s what’s going on now.”
Orsi says a major factor to keep in mind when dealing with water temperature changes involves the fish. Usually fish use an invisible thermal barrier the waters usually maintain to know where they should swim. But when the currents shift, as they are now, fish that aren’t normally seen in Alaska are swimming north.
“I think back to 2005 when we had similar conditions but it was even more warm and stagnate out in the Gulf. We had a real poor ocean year for salmon entering the ocean. So what happened was salmon entered the ocean and they’re faced with predators that aren’t normal there, for example, blue sharks or humble squid or something that are with this warm water. They will be preyed on by them. Also salmon kind of has kind of an optimal temperature that they need for maximum growth and if the water is too warm then they have to eat more to grow the same rate as they would have at a lower temperature.”
Although this doesn’t mean great things for the salmon industry, fisheries won’t feel the impact until the salmon return in another two or three years. In 2005, salmon died off and three years later, when the salmon were supposed to return, several California fisheries shut down. However, it’s still unknown how this year’s temperature increase could affect the salmon run in years to come.