Scientists from the National Oceanic and Atmospheric Administration (NOAA) have found out that the gradual warming of water temperatures can significantly affect the survivability of the Arctic cod, a silvery fish that is an important part of the food chain in the Arctic region.
The discovery was made as researchers conduct the first successful breeding of the Arctic cod in captivity as part of the NOAA's ongoing project at the Alaska Fisheries Science Center in Newport, Oregon.
The study focuses on two different stages in the Arctic cod's breeding: the juvenile fish stage and the egg and larval stages.
Benjamin Laurel, a fisheries biologist from the NOAA, said that Arctic cods are usually found in the Bering Sea and in North American waters, but they are more prevalent in the Beaufort and Chukchi seas north of Alaska.
Laurel said that the process of spawning and growing Arctic cod in captivity is valuable to scientists as it allows them to experiment on varying water temperatures in a controlled environment.
He explained that the Arctic cod relatively grows more rapidly if the water temperature is at 32 degrees Fahrenheit.
If the water, however, reaches 35.5 degrees Fahrenheit, the Arctic cod's growth is stunted and it is overwhelmed by other fishes in the Bering Strait such as Pacific cod and walleye Pollock.
Water temperatures of up to 41 degrees Fahrenheit can also kill Arctic cod eggs, according to Laurel.
The researchers intend to use the study in order to predict how the Arctic cod will behave in relation to the increasing water temperature in the ocean. The NOAA estimate that surface temperature in the Chukchi Sea rises to about 1.8 degrees Fahrenheit every ten years.
"The concern is, if the Arctic cod are not there, what happens to the ecosystem, or what happens if they're replaced by something?" Laurel said.
Aside from the survivability of the Arctic cod in warming waters, the researchers also discovered that other species of fish in the Arctic respond better to the temperature change. These include the Pacific cod, the pollock and the saffron cod.
The saffron cod specifically could even take over much of the marine territory in the Arctic if the water temperatures continue to rise. Based on the NOAA's initial tests, these fish can survive in waters as warm as 68 degrees Fahrenheit.
Saffron cod can be found mostly in the Gulf of Alaska, but if the water temperatures continue to rise as predicted by experts, the numbers of these fish could increase in northern regions.
"Here's an animal that's already in the Arctic and poised to take advantage of additional warming," Laurel added.