Chief Science Correspondent
More than 90 percent of the world's big-fish stocks have been depleted to meet the rising demands of the global fishing market. The Antarctic was, until recently, the largest untouched region of marine wildlife on Earth.
The 1959 Antarctic treaty, currently held by fifty nations - including the United States, the United Kingdom, New Zealand and Chile - was established to designate use of the Southern Hemisphere for "peaceful purposes only...[and to establish] freedom of scientific investigation." The treaty protects the continental land, but not the surrounding waters. Despite an extreme environment with temperatures ranging from -2 to 10 degrees Celsius (28 to 50 degrees Fahrenheit), the Antarctic Southern Ocean is home to many of the most diverse marine ecosystems on Earth.
Since the 1970s, commercial fisheries have pushed to fish in the Southern Ocean - particularly, the Antarctic (Dissostichus mawsoni) and Patagonian (Dissostichus eleginoides) toothfishes. The Commission for the Conservation of Antarctic Marine Living Resources, comprised of 25 nations, currently regulates all legal commercial fishing in the Southern Ocean.
Dr. Joseph Eastman, professor at Ohio University, said fishing in the Antarctic is dangerous because very little is known about these species. Currently, scientists have acquired very limited data on the life cycle, feeding behavior and seasonal spawning patterns of these species. All of this information is critical to designing a system for wide-scale fishing. Without this information, these populations are at serious risk of being depleted or even, potentially, eliminated.
"[This lack of data] makes it extremely difficult to determine what fishing activity is appropriate for these species," Eastman said in an interview.
Eastman has traveled to the Antarctic nine times since 1971, and has contributed to a 40-year study in which he helped quantify size and abundance data for a population of Antarctic toothfish caught near McMurdo Sound. The team analyzed the catch per unit effort, and reported a fairly constant population for the first 20 years of the study. After 1997, however, the population dropped off dramatically and demonstrated a steep, statistically significant decline (Figure 8). Additionally, the proportion of large versus small fish began to change during this time, with larger fish becoming less common.
“If you look at the data set, these numbers have dropped dramatically," Eastman said. "I’m not sure what’s going on. It could partially be a result of climate change. But overall, a lot is unknown.”
"Our history of fishing worldwide has been to fish now and ask questions later. We often learn about the limitations of fishing only when we overfish."
-Cassandra Brooks, Stanford University o oceano
Commercial fishing companies have been extremely successful in marketing this international delicacy, which is commonly referred to as "white gold," to the public. The Patagonian toothfish, which has been collected and sold since 1977, is currently being removed from the Southern Ocean at an estimated rate of 12,000 to 17,000 tons per year, according to ccamlr.org. The Antarctic toothfish, which has been collected and sold since 1988, is currently being removed from the Southern Ocean at an estimated rate of 4,000 tons per year.
Cassandra Brooks, Stanford University marine scientist and a science policy expert, said the high seas toothfish fishery (located in the Ross Sea) operates under an "Olympic style," meaning that all boats compete for the catch. Brooks said this style of fishing can lead to overcrowding and vessel accidents.
Brooks said that although she believes most CCAMLR members use the "best available science" to set fishing policy for these species, the high profitability of these fishes has created pressure for increased fishing in the region. She added that current data on these species suggests they are vulnerable to collapse under high population pressure.
"Our history of fishing worldwide has been to fish now and ask questions later," Brooks said in an interview. "We often learn about the limitations of fishing only when we overfish."
Eastman said the Patagonian toothfish has been overfished to a greater extent than the Antarctic toothfish because it is more accessible, as it can be found in southern regions of the Atlantic, Pacific and Indian Oceans. The Antarctic toothfish resides exclusively in the Southern Ocean, near the Antarctic shelf.
Dr. Sylvia Earle, an oceanographer for National Geographic, said fisheries have been drawn to the Southern Ocean because the rest of the world's oceans have been almost completely depleted and cannot meet the current demand for luxury fishing. Now, the world's only truly "wild" ocean is being exploited - potentially at the cost of its remarkable biodiversity.
"If they had plenty of fish around their home turf there'd be no incentive," Earle said in an interview on the 2012 documentary, The Last Ocean. "But now...the fleets are going further and further and finally to the last wild place - the last ocean."
Legal access to the region is currently held by 13 licensed fisheries, including seven exploratory fisheries (meaning the fisheries have license to collect fishes from unexplored potential fishing grounds). Assessing the true rate of fishing can be a challenge, because the above numbers do not account for illegal fishing in the Southern Ocean.
CCAMLR estimates that toothfish were caught illegally at six-fold greater rates than their legal counterparts in the 1990s, but reports that the level of illegal, unreported and unregulated fishing has declined within the past two decades. Brooks said the organization has successfully reduced the level of IUU through a number of methods including "port state measures, a catch documentation scheme and an IUU vessel list." Brooks said CCAMLR may use satellite monitoring to track IUU activities in the future.
“The United States is the biggest market for this fish in the world. As Americans, it’s our responsibility to deal with that and to have American companies stand up and say, ‘We’re not going to be a part of it, and not only are we not going to be a part of it, we want to be a part of the solution’.”
–Casson Trenor, "The Last Ocean"
Very little is known about the ecological role in the Southern Ocean, but Brooks said the activity will almost certainly alter the region's delicate ecosystem. As a large predator fish, these species likely play a critical role in controlling other populations. Brooks said that CCAMLR's mandarte requires that fisheries maintain stocks of not only the target species, but all related and dependent species.
The toothfish compete with penguins to consume smaller Antarctic fishes, and are prey to Weddell seals and killer whales. Brooks said much remains unknown regarding this complex interspecies system.
"When I think about fishing in the Antarctic and the inevitable changes it will cause throughout the system, and the vulnerable nature of the Antarctic, particularly under the pressures of climate change, what would a sustainable fishery even look like?" Brooks said.
Depletion of the toothfish could have devastating ecological effects. Removal of the toothfish species could stimulate exponential growth in the penguin populations, causing the penguins to surpass their habitat's carrying capacity. Thus, the penguin population could be vulnerable to a population collapse. Alternatively, depletion of the toothfishes may cause an increase in population growth for other, smaller fishes. Again, the environment may be unsuited for this level of growth and result in a collapse. Overfishing has the potential to impact not only the toothfishes, but all marine life within the Southern Ocean.
Brooks said she believes the most effective way to protect the toothfish is by limiting consumer consumption. She said the nonprofit organization FishWise works with businesses (including Safeway) to ensure catch from non-sustainable fisheries is kept off the market.
The Chilean sea bass is listed on Greenpeace International's Seafood Red List. The fish is sometimes labeled as "Bass from Patagonia" to deceive environmentally-conscious consumers (the alternative name generally does not show up on species alert lists), and can be purchased in supermarkets and restaurants across the world. For consumers who wish to avoid purchasing this fish, experts recommend considering the black cod, which has a similar taste, as a more sustainable alternative.
"The United States is the biggest market for this fish in the world," Casson Trenor, Greenpeace USA campaigner said on The Last Ocean. "As Americans, it's our responsibility to deal with that and to have American companies stand up and say, 'We're not going to be a part of it, and not only are not going to be a part of it, we want to be a part of the solution."
Fishing in the Southern Ocean should not continue until scientists have gathered adequate data on this species. Until then, the future of the toothfishes cannot be guaranteed. The production of a luxury food item is not worth the potential devastation of marine life in the Southern Hemisphere. hing Fishing Fi