A Tale of Two Species (in The Age of Not Knowing)

Underreported and less known is how climate change affects the oceans.

Climate change is likely the most serious threat to sockeye salmon.

(LOS ANGELES, Calif.) - It was the best of times, it was the worst of times. It was the age of information, it was the age of not knowing.

As climate change has impacted fisheries and marine ecosystems across Alaska and the Pacific Northwest, the data gathered have been surprising. The same can be said for species in the warmer climate of the South Pacific.

Sockeye

Nutrient poor, this thermal emitter has negatively impacted marine ecosytems and may disorient salmon trying to find their way back to natal streams.

The increase of carbon dioxide in the atmosphere, and therefore in the ocean, is causing the ocean acidification significantly impacting the salmon’s food chain.

Back on land, warming weather has increased the water temperatures in the rivers and streams, increasing the growth of parasites, spreading disease, and attracting predators.

The heat also reduces snowpack and causes glaciers to retreat, meaning the rivers and streams have less water. Low water makes it more difficult for salmon to travel. Shifting weather patterns have led to more severe storms and floods, which wash away salmon eggs and destroy spawning habitat.
Sockeye salmon and climate change (World Wildlife Fund)

Studies indicate that tidewater glaciers deposit nutrient material from the land to the water that stimulates the growth of marine plankton, lunch to the recently escaped juvenile salmon (smolts).

We are new to this process of collecting data points and have not yet transformed our previously limited understanding of planetary and thermographic systems into a clearer and more predictive "picture."

The media mainly focus on how climate change, through higher temperatures, storms, and sea levels, affects us here on land.

Underreported and less known is how the oceans change too, and how these changes may have economic consequences. Warm ocean temperatures are causing widespread coral bleaching in the Caribbean. In Alaska, Warm ocean temperatures are causing some species to move north.

Will the U.S. scientists and fishery managers have enough data to react? Will subsistence villages, family operations and shore-based boats be able to adapt as fish move away?

According to Rutgers:

"Climate change will force hundreds of ocean fish and invertebrate species, including some of the most economically important to the United States, to move northward, disrupting fisheries in the United States and Canada.

"Fish are sensitive to the temperature of the water where they live, and as it becomes too warm, populations often shift to where the water temperature is right for them.

"This process has already begun, though at different rates in different places. As climate change continues and the oceans warm up, the study shows, more species of fish will move north to where the temperature range is habitable for them."
-NOAA

Researchers have found that "recent shifts in the geographic distribution of marine species have been linked to shifts in preferred thermal habitats.

"Species from the U.S. and Canadian west coast including the Gulf of Alaska had the highest projected magnitude shifts in distribution, and many species shifted more than 1000 km under the high greenhouse gas emissions scenario."

Following a strong mitigation scenario, presumably this would not be the case.

Kruse warned the Senators that Bering Sea crabs may fare poorly in warming water. In contrast, the rising water temperatures favor pollock and Pacific cod, according to a news story by UAF's Carin Bailey.

"Unfortunately, some of the species that are responding well to global warming, such as arrowtooth flounder, spiny dogfish and Pacific and Jack mackerel, are species that prey on species that are highly valuable for Alaska's commercial fishermen," said Kruse.

"Arrowtooth flounder not only eat our high-value species, but they are also species that have a low market value."

Kruse said that the warming trend in Alaska waters are also punctuated by temperature spikes from more intense and more frequent El Ninos that may provide windows into Alaska's warmer future.
-The Alaska Report, Doug O'Harra

Pacific salmon appear to be expanding their range into Arctic ecosystems and may be acting as effective sentinels of climate change.

Salmon harvests voluntarily reported through the Pacific Salmon Collection Program (PSCP) suggest recent increases in both the abundance and distribution of Pacific salmon in the Arctic over the past decade.

Pacific Salmon in the Arctic: Harbingers of Change

Blue Fin

For these islands however, the tide could soon go out.

(Conservation International) Fueled by greenhouse gas emissions, ocean warming will alter the habitats of tuna, causing these fish to move outside the jurisdictions — or Exclusive Economic Zones (EEZs) — of many Pacific Islands.

Using modelling to predict how tuna stocks could move by 2050, a team of experts — led by Conservation International’s Johann Bell — found that an exodus of tuna could cut the average catch by a staggering 20 percent in 10 Pacific Island states, from Palau in the west to Kiribati in the east.

Researchers from Spanish research institute AZTI investigated the patterns of six tuna species, including albacore, Atlantic bluefin and yellowfin, between 1958 and 2004 and found that 20 of 22 tuna stocks studied had shifted their ranges towards cooler waters because of climate change.

"On average, tuna habitat distribution limits have shifted poleward 6.5 km (4 miles) per decade in the Northern Hemisphere and 5.5 km (3.1 miles) per decade in the Southern Hemisphere," the researchers wrote.

"Larger tuna distribution shifts and changes in abundance are expected in the future, especially by the end of the century."
-The Weather Channel, Pam Wright

According to (Alaska Oceanographer, Gordon) Kruse, the President's Professor of Fisheries at the University of Alaska Fairbanks School of Fisheries and Ocean Sciences, one consequence of global warming will be greater uncertainty about future productivity of fish stocks.

"Under science-based management, increasing uncertainty translates into more precaution, which means more conservative fish harvests in Alaska."
-The Alaska Report

Professor Kruse concludes by recommending more research, including improved ecosystem monitoring, more process-oriented studies, increased climate-fisheries modeling and the expansion of ecosystem-based fisheries management.

He forecasts that sightings of ocean sunfish and albacore tuna may become much more common in the future, as far north as the Bering Sea.

Rising global temperatures, due to human causation, can influence a wide array of changes in the earth’s climate including extreme weather, ocean acidification, and sea level rise.

The impacts of climate change will continue to intensify unless agreements are enacted to reduce our anthropogenic footprint.