SeaWeb - Science: Did You Know?

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Current illegal, unreported and unregulated (IUU) fishing losses worldwide have been estimated at between $10 billion and $23.5 billion annually.

IUU fisheries continue to be a major global problem. They contribute to overfishing, are an impediment to the recovery of fish populations and ecosystems and, in some regions, threaten food security. A recently published study reported on its impacts in the Raja Ampat Archipelago, an area of 45,000 square kilometers and some 600 islands in eastern Indonesia. It was found that for six fisheries—reef fish, tuna, anchovy, shark, sea cucumber and lobster—the illegal and unreported catch exceeded the reported catch by more than 1.5 times or some 40 thousand tonnes.

Source: Varkey, D.A., Ainsworth, C.H., Pitcher, T.J., Goram, Y. and Sumaila, R. 2010. Illegal, unreported and unregulated fisheries catch in Raja Ampat Regency, Eastern Indonesia. Marine Policy 34(2): 228-236.

High levels of small plastic particles have been found floating hundreds of miles off the North American east coast.

A recent study compiled results from 22 years of documenting plastic particles caught in plankton nets towed along the North American east coast. While low levels where found closer to land, rotating wind-driven currents led to far greater accumulations hundreds of miles offshore along an area stretching from about Baltimore to the Bahamas. Surprisingly, overall amounts have remained about the same over the monitoring time frame even though plastics use in the US has more than doubled in the interim. This has led some researchers to wonder whether the eastern US has improved in reducing plastics pollution or if there is another dynamic in play. For example, plastics particles may be disintegrating into pieces too small to be ensnared by the plankton nets. Or they may be eaten by zooplankton or fish, thus raising concerns over potential poisoning by the toxic chemicals within the plastic.

Source: Law, K.L. et al. 2010. Plastic accumulation in the North Atlantic subtropical gyre. Science DOI: 10.1126/science.1192321.

Researchers have spent 18 years and $200 million on understanding the Steller sea lion decline in Alaska, but the cause(s) are still unclear.

After approximately $200 million in research over 18 years—and a testament to the formidable complexity of the natural world—it remains unclear as to what caused the 80 percent decline in Alaska’s Steller sea lions during the 1960s and 70s, and why in some areas numbers continue to fall. Adding to the mystery has been the rapid recovery of the eastern population while the western population continues to struggle, even though both populations inhabit similar, heavily fished areas. Surveys of the western population have now found that numbers of adult sea lions in the far western Aleutian Islands have dropped by 45 percent and pup production by 43 percent during the past nine years. While cause(s) of the current decline in this region are unclear, a low birth rate is an indicator of a shortage in food. As a result, marine mammal scientists argue that commercial fishing for Atka mackerel and Pacific cod should be shut down in the western Aleutians given the importance of these species in the Steller sea lion diet.

Gradual progress toward ecosystem-based management of nearshore coral reef ecosystems is being made in Hawai'i.

The Hawaiian Islands encompass approximately 85 percent of the coral reef area of the United States. Many of these reef areas are facing severe fisheries depletion along with the impacts associated with a growing human population, habitat destruction, advanced fishing technologies and the gradual loss of traditional conservation practices. Increased awareness of the threats facing coral reefs was the main factor prompting a move toward an ecosystem-based management approach. Progress has been particularly successful on the western coast of the island of Hawai'i where community-based co-management and a marine protected area network have been implemented. Difficulties remain, however, in achieving the same successes in other coastal areas of Hawai'i. These include limited community involvement and weak legislative and administrative support for community-based co-management and marine protected areas, conflicts arising from the larger array of stakeholders found in more populated regions and weak enforcement of fishing regulations.

Source: Tissot, B.N. et al. 2009. Hawaiian Islands marine ecosystem case study: ecosystem- and community-based management in Hawaii. Coastal Management 37(3-4): 255-273.

Sharks and other top marine predators may use math to find their dinner.

Scientists have found a pattern of movement in 14 open-ocean marine predators, including tuna, swordfish, marlin and sharks, that indicates they use mathematical strategies to forage for food. Such movements—called Lévy flights—are characterized by random, or Brownian, motion punctuated by long forays in any direction. This system of seeking food has been recorded in waters where plankton, fish and other prey were scarce, whereas in areas where food was plentiful, these predators moved mostly in random patterns. This seems to indicate that optimal Lévy flights have naturally evolved as a search strategy for food.

Sea turtles can migrate across thousands of miles, which makes tracking their populations challenging.

Sea turtles are notoriously difficult to monitor because they live for decades and complete wide migratory travels over a large range of environments. This makes determining their population numbers difficult. All six species of sea turtles found in U.S. waters are either classified as threatened or endangered. However, a recently released study by the National Research Council (NRC) concluded that accurate determination of their numbers is not possible with the biological and life history information currently available. According to the NRC, a national plan to assess sea turtle populations is required so that effective conservation and management plans can be developed.

Read more: See the July 27, 2010, edition of Ocean Update

Source: Committee on Sea Turtle Population Assessment Methods; National Research Council, "Assessments of Sea Turtle Status and Trends: Integrating Demography and Abundance"

More than a fourth of the oil and gas produced in the United States comes from offshore areas.

The new National Ocean Policy will offer cohesive management for multiple uses of our ocean, Great Lakes and coasts, including offshore energy production and extraction of resources such as oil and gas. Offshore renewable energy sources such as wave, current, wind and solar have significant potential, but are far from being fully developed. After nine years of regulatory review, the federal government approved the nation's first offshore wind farm this past April. The plan is to build 130 wind turbines off the coast of Cape Cod.

Source: http://ocsenergy.anl.gov/guide/ocean/index.cfm

Invasive, non-indigenous species are one of the main threats to biodiversity.

The range of impacts of invasive non-indigenous species on biodiversity are well-documented. They alter ecosystem processes, reduce native species abundance and richness, change community structure and alter genetic diversity. Preventing the spread of invasive species is more cost effective than trying to tackle the issue after they have become established. However, the Global Invasive Species Programme coordinated a study that concluded a growing number of threatened species are becoming more so due to the increasing introduction and spread of non-indigenous species. The study further concluded that a substantial increase in political will and financial investment is needed to reduce the spread and control existing populations of non-indigenous invasives if many native species around the world are to be saved from extinction.

Read more and view Bioinvasion Country Profiles at www.gisp.org.

Source: Melodie A. McGeoch1 et al. 2010. Global indicators of biological invasion: species numbers, biodiversity impact and policy responses. Diversity and Distributions, 16, 95–108.

Community participation increases the success of marine reserves.

Research shows that supportive communities are one of the most important factors for the success of marine reserves. Such support has helped promote compliance to conservation rules, typically the prohibition of fishing to allow fish populations to rebound. Researchers stress the importance of including community members in the process of establishing and monitoring reserves to ensure future success.

Scientists recently found life 600 feet below the ice in Antarctica.

NASA scientists found a jellyfish-like creature and shrimp-like creature below the ice in the Western Antarctic, more than 12 miles from the sea. These findings challenge previous scientific beliefs on animals' ability to survive in extreme conditions and will likely inspire researchers to rethink what they know about life in harsh environments.

Illegally caught whale meat has been found in restaurants around the world.

Scientists used DNA to trace the origins of whale meat samples taken from restaurants in Seoul, South Korea and Los Angeles, Calif., in 2007. The meat originated from several species not listed among the respective countries' catch, including the Antarctic minke, which is an endangered whale species whose trade is banned. The findings suggest that smuggling of whale meat from Japanese whaling ships is occurring despite international bans on the trade of whale meat.

More than one billion coastal people depend upon healthy coastal and nearshore environments for survival.

More than one billion coastal people worldwide have daily living requirements that are inextricably linked to clean, fully productive and undamaged coastal and near-shore environments.

Source: Cohen et al., Estimates of coastal populations. Science 278: 1211–1212, 1997

The ocean currently absorbs more than 25 percent of the carbon dioxide that humans release into the atmosphere.

The ocean has taken up an estimated one-half of the carbon dioxide produced from the use of fossil fuels since the beginning of the Industrial Revolution. However, the ocean's ability to act as the planet's most important carbon "sink" is gradually being compromised. The massive uptake of carbon emissions has led to substantial changes in ocean chemistry and, now, is reducing its capacity for further uptake.

Sources: Bala, G., et al., Multicentury changes to the global climate and carbon cycle: Results from a coupled climate and carbon cycle model, J. Climate, 18(21), 4531–4544, 2005; Cox, P., et al., Acceleration of global warming due to carbon-cycle feedbacks in a coupled climate model, Nature, 408, 184–187, 2000.