bering sea

Disappearing snow crabs

November 21, 2023 By EarthWise Leave a Comment

Alaska snow crabs are a cold-water species found off the coast of Alaska in the Bering, Beaufort, and Chukchi Seas. They are one of ten commercially-fished species in Alaskan waters. The perils of crab fishing in this region have been well documented for many years in the reality TV series Deadliest Catch.

Last year, officials in Alaska canceled the winter snow crab season for the first time ever due to a sharp population decline. While the number of juvenile snow crabs was at record highs just a few years earlier, approximately 90% of snow crabs mysteriously disappeared ahead of the 2021 season.

This year, officials in Alaska have once again canceled the snow crab harvest season for the second year in a row, citing the overwhelming numbers of crabs – in the billions – missing from Alaskan waters.

Scientists have suspected that the warming ocean temperatures triggered this snow crab population collapse. But did the crabs move someplace else or die off? According to a new study recently published by scientists at the National Oceanic and Atmospheric Administration, warmer ocean temperatures likely caused the snow crabs to starve to death. The research team found a significant link between recent marine heat waves in the eastern Bering Sea and the sudden disappearance of the snow crabs that began showing up in surveys in 2021.

According to the study, warmer ocean water dramatically increases snow crabs’ caloric needs. But with the warmer water also disrupting much of the region’s food web, snow crabs had a hard time foraging for food and weren’t able to keep up.

Researchers expect the population may eventually find refuge in colder waters further north.

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Climate Change And Crabs

Billions of crabs went missing around Alaska

Photo, posted August 28, 2013, courtesy of Boris Kasimov via Flickr.

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Climate Change And Crabs | Earth Wise

November 8, 2022 By EarthWise Leave a Comment

Globally, there are more than 6,000 species of crabs. In Alaska’s waters alone, there are 18 species, including 10 that are commercially fished. The perils of crab fishing in this region, including freezing temperatures, turbulent seas, and raising full pots that can weigh well over a ton, have been highlighted for many years in the reality TV series Deadliest Catch.

One of those commercially-fished species is the Alaska snow crab. Alaska snow crabs are a cold-water species found off the coast of Alaska in the Bering, Beaufort, and Chukchi Seas.

In October, officials in Alaska announced that the upcoming winter snow crab season would be canceled for the first time ever due to a sharp population decline. While the number of juvenile snow crabs was at record highs just a few years ago, approximately 90% of snow crabs mysteriously disappeared ahead of last season. Officials also canceled the Bristol Bay red king crab harvest for similar reasons for the second year in a row.

The closures dealt a severe blow to crab fishers in the region. According to the Alaska Seafood Marketing Institute, Alaska’s crab fishing industry is worth more than $200 million.

The canceled seasons also raise questions about the role of climate change in the snow crab population crash. While the causes of the decline are still being researched, scientists suspect that warmer temperatures are responsible. Temperatures in the Arctic region have warmed four times faster than the rest of the planet.

As the climate continues to change, the warming waters around Alaska may become increasingly inhospitable to snow crabs and other species.

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Alaska’s Bering snow crab, king crab seasons canceled

Alaska cancels snow crab season for first time after population collapses

Photo, posted November 16, 2010, courtesy of David Csepp / NOAA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Shrinking Ice In The Bering Sea | Earth Wise

October 19, 2020 By EarthWise Leave a Comment

The Bering Sea forms the divide between the two largest landmasses on Earth: Eurasia and the Americas. Recent analysis of vegetation from a Bering Sea island has determined that the extent of sea ice in the region is the lowest it has been for over 5,000 years.

St. Matthew Island, a small island in the middle of the Bering Sea, has essentially been recording what is happening in the ocean and atmosphere around it, in the form of the composition of peat layers on the island. By analyzing the chemical composition of peat core samples, scientists can estimate how sea ice in the region has changed over the course of time.

Changes in the relative amounts of two oxygen isotopes in the sediment and plant debris trapped in the peat on the island reflect the nature of precipitation during the period when the peat layers formed. That ratio is correlated with the amount of sea ice in the region. Satellite data acquired over the past 40 years confirms this correlation.

Analysis of the data shows that the current ice levels are unprecedented in the last 5,500 years. These long-term findings affirm that reductions in Bering Sea ice are due to more than recent higher temperatures associated with global warming. Atmospheric and ocean currents, which have also been altered by climate change, play a large role in the presence of sea ice.

Summertime sea ice in the Arctic was expected to reach its second-lowest extent in September in 40 years of observation. Sea ice typically builds up again each winter, but the changes in ice extents actually lag behind changes in greenhouse gas level by decades. Future ice loss is already built into the system.

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Bering Sea ice extent is at most reduced state in last 5,500 years

Photo, posted December 2, 2012, courtesy of Bering Land Bridge National Preserve via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Record Low Ice In The Bering Sea | Earth Wise

January 30, 2020 By EarthWise Leave a Comment

The Bering Sea is the area of the far northern Pacific Ocean that separates Alaska from Russia. Sea ice in the Bering Sea shrank to its lowest levels in recorded history in 2018, an event with profound effects on northwest Alaska residents who depend on marine resources for food, cash, and culture.

The loss of ice is indicative of very rapid change in the entire northern Bering Sea ecosystem with ramifications for everyone in the region. A new peer-reviewed study published in the Bulletin of the American Meteorological Society examined the details and consequences of the drastic changes in the Bering Sea.

The study found that the maximum daily Bering Sea ice was the lowest on record, and the widespread impacts of that fact include unprecedented weather effects, marine wildlife die-offs, and sightings of animals outside of their normal range. Ecological changes included the first documented mass strandings of ice-associated seals, a redistribution of thermally sensitive fish, and a multispecies die-off of seabirds due to starvation.

Persistent and anomalous warm winter weather contributed to poor ice conditions that resulted in a fatal accident on an ice road and retreating and fractured sea ice led to ice-laden flooding that caused power outages and infrastructure damage. In addition, there have been more than 50 reports of unusual events related to weather and marine wildlife.

The record-low sea ice is a consequence of the warming climate resulting in a warmer ocean, later arrival of sea ice, and more frequent storms than in the pre-industrial era. These conditions are continuing to increase in occurrence.

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Record low level of Bering Sea ice causes profound, widespread impacts

Photo, posted April 7, 2014, courtesy of Allen Smith via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Saildrones For Science

July 11, 2018 By EarthWise Leave a Comment

Nine years ago, engineer Richard Jenkins broke the world land speed record for a wind-powered vehicle with a sailboat on wheels driving across a dry lakebed at 126 miles per hour. After years of engineering development, his technology has now taken on the form of a saildrone that can autonomously sail the sea gathering ecologic, oceanic and atmospheric data.

Strange Ocean Current Behavior

January 18, 2018 By EarthWise 4 Comments

The Beaufort Gyre is a massive wind-driven current in the Arctic Ocean. Located north of Alaska and Canada’s Yukon Territory, it is like a giant spinning top that corrals vast amounts of sea ice in the far north.