- Email: [email protected]
Mystery of fluctuations in sea lion populations
Volume
X/Number
4/.4pril
1998
Jim Frank and his colleagues at the Argonne National Laboratory developed a new technique funded by the NTEC. Previous techniques only ever produced 60% ester concentrations as the water produced in the reaction eventually halted it. Expensive distillation techniques were then the only way to concentrate it into a usable form. However the new system employs a very fine membrane through which only very small molecules can pass. This means that the water evaporates to the other side of the membrane and the lactate esters produced are nearly pure. This will reduce the costs making the new solvents available at about $2 per kilogram which puts them in the same bracket as the current halocarbon solvents. This ester can be used in all paint thinners and cleaning agents in all aspects of industry and could replace about 80% of the current ozone-depleting solvents. A commercial plant is expected to be open by the year 2000:
In Alaska, the Stellar sea lion, has been reclassified from a threatened to an endangered species as the populations continue to decline and efforts are being made to try and understand this trend. In this case there seems to be a more obvious link between the decline and decreased food availability. There have been considerable system changes in the Bering Sea and the Gulf of Alaska which could have led to this decline in food. However, it is very difficult to collect really accurate information on available food species. Fish sanctuaries were set up in 1990 around the sea lion rookeries where trawling is banned within 10 miles of the sites and boat movements within three milts. Reductions in the populations are not expected to increase, however, continuing research is needed to try and unravel the underlying causes of this decline.
Mystery of Fluctuations Sea Lion Populations
In many parts of the world attempts to prevent further demise in turtle populations are in operation. Greenpeace have been involved in two areas recently in attempts to protect a number of turtle species in the Americas and Cyprus. An Inter-American Convention for the Protection and Conservation of Marine Turtles has been signed by Brazil, Costa Rica, Nicaragua, Peru, the US and Venezuela. However a number of countries, in spite of their intcrcst, have yet to sign, in particular Mexico, who originally supported the Convention. This has caused surprise and concern at Grecnpcace and the World Wildlife Federation. Mexico had been working with regional experts to strengthen protection of the marine turtle in 1994 and 1995. They also have had a ban on the capture marine turtles since 1990 and a ban on the removal of eggs from nesting sites since 1996. Greenpeace have challenged the Mexican Ministry of the Environment and the Mexican Congress to urgently sign the proposed Convention. It is thought that if they signed another group of countries would also participate. Turtles had been a major part of local economies in Mexico since the 1950s both meat and shells being traded. Problems with the populations really began after 1986 when a very large number were caught, totalling 15,000 tons and there was subsequent severe drop in the population. Commercial swordfish fishing also appears to be one of the greatest threats to turtles with over 2000 being killed in the operations each year. Even the commercial shrimp fishing in the Gulf of Mexico is considered a threat. Meanwhile, the British army has been prevented from carrying out military exercises on the Akamas peninsula in response to calls from Greenpeace that the operations affect the turtle nesting sites in the area. They will bc carrying out their exercises elsewhere. The Cyprus government has also undcrtakcn to negotiate a
in
Sea lion populations in both Australia and Alaska do not seem to be rccovcring as effectively as many seal populations. The underlying causes of this remain mysterious and calls for increased research are being made in both countries. Inexplicable fluctuations in the Australian sea lion populations have been recorded in a report by the Commonwealth Scientific and Industrial Research Organisation (CISRO) and the National Parks and Wildlife South Australia. There is concern that the population has levelled off and may even be declining in spite of the efforts being made to conserve the species. Pup mortalities in two colonies have been shown to hc very variable, in the last two years ranging from as low as 4% to as high as 50%. There seemed to be no obvious reasons for these fluctuations. The mortality of thcsc.pups could be due to a number of factors such as parasitic infection of hookworm, food shortage for the females during lactation and even adult male aggression, However, interaction with humans may also be a problem. The Australian sea lion is an endemic species and very popular with tourists. Thousands of tourists visit the colonies every year although there is no evidence that this could be causing disturbance to their rather sensitive and unusual breeding cycle. This species is the only pinniped to have a changing breeding season. As the gestation period is eighteen months, the pupping season alternates between winter and summer or spring and autumn. This makes it more difficult to unravel the reasons for the population fluctuations. It may in fact be suffering from increased competition with the fur seal which is doing very well, or just settling out at the population’s previous normal levels. More intensive research is being called for.
Turtle Preservation Attempts
253
X/Number
4/.4pril
1998
Jim Frank and his colleagues at the Argonne National Laboratory developed a new technique funded by the NTEC. Previous techniques only ever produced 60% ester concentrations as the water produced in the reaction eventually halted it. Expensive distillation techniques were then the only way to concentrate it into a usable form. However the new system employs a very fine membrane through which only very small molecules can pass. This means that the water evaporates to the other side of the membrane and the lactate esters produced are nearly pure. This will reduce the costs making the new solvents available at about $2 per kilogram which puts them in the same bracket as the current halocarbon solvents. This ester can be used in all paint thinners and cleaning agents in all aspects of industry and could replace about 80% of the current ozone-depleting solvents. A commercial plant is expected to be open by the year 2000:
In Alaska, the Stellar sea lion, has been reclassified from a threatened to an endangered species as the populations continue to decline and efforts are being made to try and understand this trend. In this case there seems to be a more obvious link between the decline and decreased food availability. There have been considerable system changes in the Bering Sea and the Gulf of Alaska which could have led to this decline in food. However, it is very difficult to collect really accurate information on available food species. Fish sanctuaries were set up in 1990 around the sea lion rookeries where trawling is banned within 10 miles of the sites and boat movements within three milts. Reductions in the populations are not expected to increase, however, continuing research is needed to try and unravel the underlying causes of this decline.
Mystery of Fluctuations Sea Lion Populations
In many parts of the world attempts to prevent further demise in turtle populations are in operation. Greenpeace have been involved in two areas recently in attempts to protect a number of turtle species in the Americas and Cyprus. An Inter-American Convention for the Protection and Conservation of Marine Turtles has been signed by Brazil, Costa Rica, Nicaragua, Peru, the US and Venezuela. However a number of countries, in spite of their intcrcst, have yet to sign, in particular Mexico, who originally supported the Convention. This has caused surprise and concern at Grecnpcace and the World Wildlife Federation. Mexico had been working with regional experts to strengthen protection of the marine turtle in 1994 and 1995. They also have had a ban on the capture marine turtles since 1990 and a ban on the removal of eggs from nesting sites since 1996. Greenpeace have challenged the Mexican Ministry of the Environment and the Mexican Congress to urgently sign the proposed Convention. It is thought that if they signed another group of countries would also participate. Turtles had been a major part of local economies in Mexico since the 1950s both meat and shells being traded. Problems with the populations really began after 1986 when a very large number were caught, totalling 15,000 tons and there was subsequent severe drop in the population. Commercial swordfish fishing also appears to be one of the greatest threats to turtles with over 2000 being killed in the operations each year. Even the commercial shrimp fishing in the Gulf of Mexico is considered a threat. Meanwhile, the British army has been prevented from carrying out military exercises on the Akamas peninsula in response to calls from Greenpeace that the operations affect the turtle nesting sites in the area. They will bc carrying out their exercises elsewhere. The Cyprus government has also undcrtakcn to negotiate a
in
Sea lion populations in both Australia and Alaska do not seem to be rccovcring as effectively as many seal populations. The underlying causes of this remain mysterious and calls for increased research are being made in both countries. Inexplicable fluctuations in the Australian sea lion populations have been recorded in a report by the Commonwealth Scientific and Industrial Research Organisation (CISRO) and the National Parks and Wildlife South Australia. There is concern that the population has levelled off and may even be declining in spite of the efforts being made to conserve the species. Pup mortalities in two colonies have been shown to hc very variable, in the last two years ranging from as low as 4% to as high as 50%. There seemed to be no obvious reasons for these fluctuations. The mortality of thcsc.pups could be due to a number of factors such as parasitic infection of hookworm, food shortage for the females during lactation and even adult male aggression, However, interaction with humans may also be a problem. The Australian sea lion is an endemic species and very popular with tourists. Thousands of tourists visit the colonies every year although there is no evidence that this could be causing disturbance to their rather sensitive and unusual breeding cycle. This species is the only pinniped to have a changing breeding season. As the gestation period is eighteen months, the pupping season alternates between winter and summer or spring and autumn. This makes it more difficult to unravel the reasons for the population fluctuations. It may in fact be suffering from increased competition with the fur seal which is doing very well, or just settling out at the population’s previous normal levels. More intensive research is being called for.
Turtle Preservation Attempts
253