Diminutive little critters, only about two inches (five centimeters) in length, but they represent a tremendous, irreplaceable part of the world’s ecosystem. These shrimp-like crustaceans are the base foodstuff of much of planet earth.
Krill feed on phytoplankton; the microscopic, single-celled plants that drift near the ocean’s surface and live off CO2 and sunlight. They are the main staple of literally hundreds of different species; without krill, most of the life forms in the Antarctic would disappear.
Alarmingly, there are recent studies that show Antarctic krill stocks may have dropped by 80 percent since the 1970s. Scientists attribute these declines in part to ice cover loss caused by global warming. This ice loss removes a primary source of food for krill: ice-algae.
Pink and opaque, Antarctic krill are among the largest of the 85 known krill species. Their estimated numbers range from 125 million tons to 6 billion tons in the waters around Antarctica. During certain times of year, krill congregate in swarms so dense and widespread that they can be seen from space.
Antarctic krill can live up to 10 years, an amazing longevity for such a heavily hunted creature. They spend their days avoiding predators in the cold depths of the Antarctic Ocean, some 320 feet (100 meters) below the surface. During the night, they drift up the water column toward the surface in search of phytoplankton.
Besides the phytoplankton they feed upon, krill are perhaps the most important species on the planet; we'd likely all perish without them.
Antarctica At Risk For Environmental Disaster?
By Philip Ross
A Chinese fishing ship that caught fire in the Antarctic on Wednesday highlights a pervasive environmental concern: The overfishing of krill in the Antarctic region.
A crew of 97 people was out fishing for krill in the waters off Antarctica, about 34 miles from Chile's Bernardo O'Higgins research base near the northern tip of the Antarctic Peninsula, when the Chinese fishing vessel caught ablaze. AP reports that a nearby Norwegian vessel rescued the 97 members of the fishing boat, Kai Xin, and took them aboard the Juvel.
Fishing Expedition Gone Awry
Unsure of how much fuel the ship carried, Chilean officials worried about a possible environmental hazard should the ship sink. Chile's air force is flying to the ship today to check on the status of the ship on fire in Antarctica. It's possible that the ship will be towed to Punta Arenas, a harbor near the southern tip of Chile, as long as it doesn't start to sink, according to AP.
While the immediate danger from the ship was a possible oil spill, the disaster highlights another, more pervasive environmental concern.
Greenpeace, a non-governmental environmental group that focuses on environmental issues like global warming, deforestation and overfishing, pointed out that the Chinese fishing ship that caught fire was part of a fleet of 50 other krill fishing vessels. The Commission for the Conservation of Antarctic Marine Living Resources, or CCAMLR, authorized the fleet to fish for krill off the Antarctic coast.
"They don't know how the ecosystem might be affected by fishing for krill, which forms part of the foundation for the entire ocean food chain," Milko Schvartzman, a Greenpeace campaigner, told AP.
Are krill being overfished, and is the Antarctic at risk for an environmental disaster?
Krill Fishing On The Rise
Krill, which are tiny shrimp about the size of a paperclip, are the primary food source for many marine mammals like blue whale and seals. According to National Geographic, scientists estimate that the combined weight of all the krill in the Antarctic is more than the total weight of all humans on the planet; some say it's as high as 6 billion tons.
Recent studies show that since the 1970s, Antarctic krill stocks may have declined by 80 percent. This population degradation is attributed mainly to the loss of ice cover due to global warming, as ice-algae is the main food source for krill.
"Simply put, without krill, most of the life forms in the Antarctic would disappear," National Geographic reports.
Environmental Disaster On The Way?
The CCAMLR, which makes annual reviews of fishing areas in the Antarctic, sets catch limits for krill fishing in the areas surrounding Antarctica. CCAMLR's annual catch limit in the Southern Ocean is 3.47 million tons of krill. According to the commission, Krill fishing spiked in the mid-1980s and 1990s, but one study reports that new and efficient fishing techniques has the commercial catch of krill on the rise.
The Guardian reports that fished krill is mainly used as fish-farm feed and to make Omega 3 oil, among other health supplements. The global fish-farming industry is relying more heavily on krill-based fish feed, according to the Nature Publishing Group.
Another worry is the number of fishing vessels being deployed in the Southern Ocean. Norway is now operating three ships, for example, and China is expected to rapidly increase its krill fishing after sending its first vessel this year. "If China starts fishing in a big way, catch will expand rapidly, outstripping our ability to orderly manage it," says Steve Nicol, a marine ecologist with the Australian Antarctic Division in Kingston, Tasmania, who advises the Australian government on krill fisheries.
Could the rise in krill fishing coupled with the ever-increasing demand for krill feed mean an environmental disaster for the Antarctic region?
Antarctic krill populations decreasing
Some fear havoc in food chain
From Correspondent Rusty Dornin
SAN FRANCISCO (CNN) -- These are tough times at the bottom of the food chain.
Krill -- tiny shrimp-like creatures eaten by whales, seals, birds and fish -- are dwindling in number. Observers fear they may disappear altogether from the sea's menu.
"There has been almost a 90 percent decrease in krill abundance since 1980," said Valerie Loeb of the Moss Landing Marine Laboratory.
Krill is a main food source; its loss might cause a domino effect that could wreak havoc on the marine ecosystem. "Should this decline continue I would expect to see dramatic reductions in whale populations in that same area," said Kenneth Coale, also of Moss Landing.
Krill feed on algae beneath the ice. During the past 20 years the supply of sea ice has melted as temperatures have risen in Antarctica.
Many scientists blame global warming, which has been linked to fossil fuel emissions. "Some people view krill as the canary in the coal mine of global warming," Coale said. "It is certainly a wake-up call for scientists."
Already some penguin populations on Antarctic islands have been reduced by up to 50 percent.
Krill also is used as a supplement for chicken and cattle feed. Some 300,000 tons are harvested annually.
If the krill population is declining, researchers say harvesting could make the situation worse.
"The extent to which humans continue to harvest large amounts of krill will now, even more so, affect those natural populations of whales and penguins in the Antarctic," Coale said.
As the waters warm and the krill disappear, another creature, salp, replaces them. The problem is the salp has little appeal to hungry Antarctic creatures.
"Whales don't eat them. Penguins don't eat them. They're kind of a dead end for the food chain down there," Coale says.
If the warming is just a climatic fluctuation, krill population may return once temperatures cool. If not, Loeb says, "the Antarctic peninsula region in 20 years will be very different than it is today."
NOAA Bans Commercial Harvesting Of Krill
The National Oceanic and Atmospheric Administration (NOAA) has published a final rule in the Federal Register prohibiting the harvesting of krill in the Exclusive Economic Zone (EEZ) off the coasts of California, Oregon, and Washington. Krill are a small shrimp-like crustacean and a key source of nutrition in the marine food web.
"Krill are the foundation for a healthy marine ecosystem," said Mark Helvey, NOAA's Fisheries Service Southwest Assistant Regional Administrator for Sustainable Fisheries. "Protecting this vital food resource will help protect and maintain marine resources and put federal regulations in line with West-Coast states."
While the States of California, Oregon and Washington currently have regulations prohibiting the harvesting of krill within three miles of their coastlines, there was no similar federal restriction within the three to 200-mile confines of the EEZ.
The krill prohibition was adopted as Amendment 12 to the Coastal Pelagic Species Fishery Management Plan (FMP), which was developed by the Pacific Fishery Management Council (PFMC) under the Magnuson-Stevens Fishery Conservation and Management Act. The krill harvest prohibition was originally proposed to the PFMC and NOAA Fisheries Service by NOAA's Office of National Marine Sanctuaries. Today's rule implements Amendment 12 to the FMP and is intended to preserve key nutritional relationships in the California Current ecosystem, which includes five National Marine Sanctuaries.
"This is a great success for protecting the entire California Current ecosystem", said William Douros, West Coast Regional Director for NOAA's Office of National Marine Sanctuaries. "This decision reflects strong teamwork within NOAA and a commitment to addressing the issues raised by the Pacific Fishery Management Council and Sanctuary Advisory Councils."
Amendment 12 adds all species of krill under a new category, "prohibited harvest species." This new group may not be caught or taken by any fishery or gear type within the EEZ.
Krill are important because they convert microscopic phytoplankton into a food source for numerous other species and are a principal food source for many species of fish, seabirds and marine mammals. Some of the species that depend on krill as prey are listed as threatened or endangered under the Endangered Species Act, and many others are important as target species for commercial and recreational fisheries on the west coast.