The waters of the Alaskan Aleutian Islands registered the warmest temperatures of winter in more than a century, as part of a decade-long warming according to the report published from the National Oceanic and Atmospheric Administration.
The record-breaking temperatures in the central and western Aleutians were tempered during the course of this year. However, temperatures were warmer than normal for the remainder of the year in the waters surrounding the 1,100-mile chain stretching from southwest Alaska according to 2023’s NOAA Fisheries Ecosystem Status report for the region.
The Aleutians report is among three annual reports on the state of ecosystems released from NOAA Fisheries for marine areas in Alaska. The reports, prepared by huge teams of scientists were released earlier in the month and were presented at the North Pacific Fishery Management Council which is the body that decides on the rules for commercial fishing regulations in the federal waters around Alaska.
The annual reports offer a snapshot of the current climate and provide information about the conditions to come in a warmer climate, details needed to oversee the harvest of fish and other tasks, NOAA Fisheries said in an announcement.
“Warming at rates that are four times higher than that of the ocean the Alaskan Arctic ecosystems serve as a gauge for the effects of climate change. More than ever, having climate-related and ecosystem data and information is vital to ensure adaptive resource management, as well as resilient recreational, commercial, and subsistence fisheries as well as coastal and rural communities,” Robert Foy, director of the NOAA’s Alaska Fisheries Science Center, stated in the statement.
The Bering Sea and the other sea waters around Alaska are the source of more than half of all the country’s commercially harvested seafood.
In the Aleutians the species most susceptible to the warming conditions include Pacific cod, as stated in the Aleutian state of the ecosystem report. There are many reasons for this, NOAA Fisheries biologist Ivonne Ortiz informed the council in her presentation of the report.
“Pacific cod is found to have a limited range of temperatures needed for eggs to hatch,” Ortiz said. The range, which spans between 3 and 6 degrees, has not been overextended in the oceans she mentioned.
Temperatures rising also raise Pacific cod’s energy requirements, Ortiz explained. “The costs of life are greater and the costs of feeding, growing or pooping, having sexual activity, and swimming around, is more expensive which means they must either eat prey with a greater calorific content or consume more prey in order to make up for this,” she said. However, food of high-quality for Pacific cod is not readily accessible throughout the Aleutian region, she added.
Additionally, they are susceptible and tolerant to temperature increases are Atka mackerel, a key species used for commercial harvests as per the status report of the ecosystem. However, pink salmon that originate from the eastern part of Kamchatka located situated on the Russian side of the ocean, are flourishing, and have the third highest number of individuals recorded in the report.
Warmer temperatures mean higher risk of toxins from algal sources, and the record of this year is proof of this. Mussels that were discovered in June in Sand Point, Unalaska, False Point and Akutan, communities in the Aleutians’ eastern region or near the western end in the Alaska Peninsula, had levels of paralytic shellfish toxin levels that were 47 times higher than the amount considered safe for humans to eat, as per the Aleutians ecological status report.
“Cooled however, it’s not super cool’
The Bering Sea and the Gulf of Alaska are recovering from the extreme heatwaves which struck the region in recent times as per the reports on ecosystem status released for these regions. Temperatures are now back to more normal levels, however the unprecedented heatwaves continue to have consequences, as per the reports.
The Bering Sea is still warmer than the average for the past few years although it has been cooling following the heatwaves, NOAA Fisheries biologist Elizabeth Siddon informed that the North Pacific Fishery Management Council during her report. document.
“It has cooled, but it isn’t cool.” she added.
The ecological conditions are diverse complicated and, in some instances, difficult to explain, Siddon said.
On the flip side certain crab stocks are continuing to suffer their decline that led to the closure of their harvests in a disruptive manner as per the report on that marine zone. In the northern region of the Bering Sea jellyfish, which are a less nutritious food source for fish species in the food chain and an adversary to groundfish as a source of food sources – are growing. In the southern region of eastern Bering Sea, there has been a continuation of the decade-long decline in the production of high-quality plankton which is the foundation of food chains. In the year of 2018 it was the lowest levels for several years in this region of the Bering Sea, Siddon said. In contrast there was a continued trend towards high levels of coccolithophores. This is a form of phytoplankton, which is considered a unfit for consumption in on the web of food, Siddon explained.
On the bright side in the report, as per the Bering Sea ecosystem report, there was a slight increase in the juvenile Chinook as well as chum salmon in the northern regions suggesting a possible improvements for Western Alaska salmon runs that had been declining in recent times. The reproduction rate was higher for some seabirds. This is an outcome that comes after several years of bird deaths in the report.
The Gulf of Alaska, where the extreme heatwaves that hit the ocean have caused Pacific cod stock to plummet to the point that harvests were cancelled in the last few years and there’s an ongoing pattern of low cod populations along with a decrease in the population of for arrowtooth and halibut flounder as per the region’s state of the ecosystem report. However, sablefish populations and perch, two important commercial species, continue to grow in accordance with the report.
Be on the lookout to watch out for El Nino effects
The warming of spring that is predicted with the current El Nino weather pattern could create more chaos in into the Gulf of Alaska, NOAA Fisheries biologist Bridget Ferriss said in her speech before the council.
Because larvae and juvenile groundfish are the most vulnerable to temperature changes warming seas may cause harm to the cod larvae as well as pollock and the northern rock sole NOAA Fisheries biologist Bridget Ferriss said to the council. “These won’t be the species that we’ll be fishing the next time around,” Ferriss said. But that could be a problem for the stock of future years she added. Adults could be at risk as well, since warming will reduce the quality and the fat content of zooplankton she explained.
Adult fish that are potentially vulnerable such as pollock will not necessarily be less plentiful however, their bodies may be altered, Ferriss said. “We may see thinner fish next year because they’ve got a smaller prey base that zooplankton feeds on,” she said.
One of the species that may benefit from El Nio-driven warm temperatures are sablefish. They have seen a surge in popularity in recent years alongside the arrowtooth flounder, the southern rock sole, and Halibut larvae Ferriss stated.
The effects of marine heatwaves are profound as research has demonstrated.
The latest study describes why the unusually hot temperatures on the Bering Sea in 2018 – the year that had the lowest amount of winter sea ice in the Bering Sea since the records started in 1850 changed the phytoplankton population that form the foundation of our food web.
Normally, sunlight in spring can stimulate algae development on the underside of the sea ice and the algae continues to grow when the melting ice begins to melt. The phytoplankton then falls into the ocean floor, acting as food to bottom-dwelling species which are part of what is known under the designation of benthic zones. If ice isn’t present the blooms of spring phytoplankton occur in open waters, feeding marine life that is closer to the surface and is considered to be the pelagic zone but not being able to reach the benthic zone that is at the bottom.
Benthic species include clams as well as snails, which are eaten by mammals, such as seals and walruses. The species that are pelagic include herring, salmon, and pollock and seabirds that feed on fish..
The study, conducted by scientists at NOAA as well as University of Washington, University of Washington and other institutions, tracks the varying Bering Sea spring blooms that took place from 1998 until the year 2018. It concluded that, while the time of blooms did not change during the time period, the nature of the blooms did alter.
When the cycle of warm-years increases and the spring shifts are more intense, phytoplankton blooms could remain in favor of pelagic species especially in the northern parts of the Bering Sea according to the study’s authors.
