Sea Technology

MAY 2013

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in the past, with nearly 400 pups rescued in Los Angeles alone. San Diego, Orange, Santa Barbara and Ventura counties have also seen high numbers of abandoned pups. Because of overcrowding, shelters have sent pups up the coast to facilities that have more space. Of the pups born in June, almost half have died. Typically, the statistic is less than one third. Scientists are struggling to understand what NOAA has called an "unusual mortality event." Most of the rescued pups have weighed in about 20 pounds less than average. Scientists suspect the pups are swimming to shore, as April is usually when they frst leave their mothers. Scientists believe that a shortage in the sea lions' food supply, anchovies and sardines, or disease could be behind the overwhelming number of starving pups. Researchers predict that more sea lions will be found and the trend will continue up the California coast. High Levels of Nitrogen Found in Upwelling Regions The upwelling regions of oceans typically have nutrient-flled waters. ARGENTINA AUSTRALIA AUSTRIA AZERBAIJAN BANGLADESH BELGIUM BELIZE BERMUDA BOTSWANA BRAZIL BRITISH WEST INDIES BRUNEI BULGARIA CANADA CANARY ISLANDS CENTRAL AFRICAN REP. CHANNEL ISLANDS CHILE CHINA 76 st / MAY 2013 COLOMBIA COOK ISLANDS COSTA RICA CROATIA CUBA CYPRUS CZECH REPUBLIC DENMARK DOMINICAN REPUBLIC ECUADOR EGYPT ENGLAND ESTONIA FAEROE ISLANDS FIJI FINLAND FRANCE GERMANY GHANA Microbes in these regions convert nitrogen into other gases, causing scientists to predict low levels of nitrogen fxation. However, research has found high levels of nitrogen fxation in these areas, according to a study in Geophysical Research Letters. The study examined the microbes in an upwelling region of the Atlantic near the equator throughout May and June 2009. The results showed that nitrogen fxation was up to seven times higher during upwelling. The researchers suggest that waters rich in iron but with a low ratio of nitrate to phosphate create a bloom of nondiazotrophic phytoplankton, which remove the nitrate. The microbes will use the leftover iron and phosphate, causing the rate of nitrogen fxation to rise. The fndings could lead to a better understanding of nitrogen and carbon dynamics in upwelling regions. Overfshing Leads to Genetic Changes The common practice of removing the largest fsh from the population could make smaller, less fertile fsh GREECE HONDURAS HONG KONG ICELAND INDIA INDONESIA IRAN IRELAND ISRAEL ITALY JAMAICA JAPAN JORDAN KAZAKHSTAN KENYA KOREA KUWAIT LAOS LATVIA LITHUANIA MACEDONIA MALAYSIA MALDIVES MALTA MAURITIUS MEXICO MONACO MOROCCO NORTHERN IRELAND NAMIBIA NETHERLANDS NEW CALEDONIA NEW ZEALAND NICARAGUA NIGER NIGERIA NORWAY OMAN www.sea-technology.com more prominent, according to a paper in Frontiers in Ecology and the Environment. The paper discusses a lab study that suggests that these changes are occurring at the genetic level. The study modeled a naturally occurring fshing environment and looked at the genetics behind the size of fsh. Smaller size and fewer offspring has increasingly become the trend among fsh populations throughout the past century. Scientists have noted the pattern, but have not yet been able to pinpoint the cause. Two theories have developed to explain the downsize. The harvesting of the largest fsh in the population and the animals' response to a changing environment, like an altered food supply, were both cited as reasons. Changes in DNA will make it more diffcult for fsheries to recover from depleted sources. Harvesting higher numbers of smaller fsh could help to mitigate the problem. The study suggests that commercial fshers will need to consider the evolutionary changes in the fsh population if fsh are to remain a major source of food. n PAKISTAN PERU PHILIPPINES POLAND PORTUGAL QATAR REPUBLIC OF CHINA REPUBLIC OF KOREA REPUBLIC OF PANAMA ROMANIA RUSSIA SAUDI ARABIA SCOTLAND SERBIA SINGAPORE SLOVENIA SOLOMON ISLANDS SOUTH AFRICA SPAIN SRI LANKA SWEDEN SWITZERLAND TAIWAN THAILAND TONGA TRINIDAD & TOBAGO TUNISIA TURKEY TURKS & CAICOS ISLANDS UKRAINE UNITED ARAB EMIRATES UNITED STATES URUGUAY VENEZUELA VIETNAM WALES WEST INDIES

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