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January 2012 Issue

Left to Breed in Warmer Waters, Damselfish Offspring Adapts
Australian scientists have discovered that one species of tropical fish, by adjusting over several generations, has a greater capacity to cope with rising temperatures than previously thought.

The scientists, a team from the ARC Centre of Excellence for Coral Reef Studies, James Cook University and the Commonwealth Scientific and Industrial Research Organisation, were studying how fish would cope with the elevated sea temperatures expected by 2050 and 2100.

The team first exposed damsel fish to water temperatures 1.5° to 3° C above what is typical today, causing a decline in the fish's aerobic activity and affecting their ability to swim quickly from predators. After several generations at higher temperatures, however, the offspring were found to have almost completely adjusted.

The scientists said they have yet to fully understand the mechanisms involved that allow offspring to cope, but "it doesn't seem to be simple Darwinian selection over a couple of generations," said team leader Philip Munday of the ARC Centre. "Instead, there has been a transmission of information between the generations that enables damselfish to adjust to higher water temperatures."

The two temperatures used in the trial represent likely tropical ocean temperatures at the midcentury and by 2100, based on trends in CO2 emissions. The researchers caution the finding applies so far only to a single coral reef fish species. It also does not address the more complex issue of the survival of the coral habitat itself or the effects of warming on plankton in the food chains on which fish depend.

There are likely to be penalties for fish that successfully adapt, the team said; initial observations suggest the offspring are on average smaller. For more information, visit www.coralcoe.org.au.

Nautilus Drilling Campaign Boosts Resource Estimates
A 99-hole, 1,475-meter drilling campaign in the Bismarck Sea conducted between November 2010 and May 2011 has increased Nautilus Minerals' (Toronto, Canada) indicated copper and gold resources by about 25 percent.

The updated resource assessment, released in November, focused on the area containing the Solwara 1 deposit. A total of 71 holes were drilled in this lease area, for a total of 1,147 meters. The remainder of the drilling was conducted in Exploration Lease 1374, which hosts Solwara 12.

The resource update was prepared by Golder Associates Pty Ltd. (Hawthorn, Australia). Contained copper in indicated resources at Solwara 1 increased 25 percent to about 74,000 tonnes, while contained copper increased 23 percent to about 166,000 ounces. A maiden inferred resource has been declared at Solwara 12, 25 kilometers to the northwest of Solwara 1, of 230,000 tonnes, grading 7.3 percent copper and 3.6 grams of gold per tonne of ore.

Nautilus said the increases in contained metal within the resource are a result of additional tonnes and higher grades due to successful resource drilling that identified further high-grade ore zones. The increase in tonnes was also partly due to a reduction in the cut-off grade from 4 percent copper, used in the prior 2008 resource statement, to a copper equivalent cut-off grade of 2.6 percent in the 2011 resource, following refinements in the project design. For more information, visit www.nautilusminerals.com.

Genetic Marker Test Could Help Feds Enforce Seafood Regulations
Research in marine forensics by scientists at the Virginia Institute of Marine Science could allow federal agents to genetically test blue marlin to quickly and accurately determine their ocean of origin. The test is needed to ensure that the blue marlin sold in U.S. seafood markets were not taken from the Atlantic Ocean.

The research team—graduate student Laurie Sorenson, molecular biologist Jan McDowell and professor John Graves—reported the findings in the October issue of Conservation Genetics Resources.

The new test uses "microsatellite markers," repeating sequences of genetic material along the strands of DNA that lie within an organism's cells. Closely related individuals, such as those within either the Atlantic or Indo-Pacific stock, tend to share similar patterns of repetition, thus providing a "genetic fingerprint" for identification.

The team identified the new markers by examining blue marlin heart tissue and tested their effectiveness by analyzing tissues from 40 blue marlin—20 from mid-Pacific waters near Hawaii and 20 from the coast of Ghana in the equatorial eastern Atlantic. For more information, visit www.vims.edu.

In Warming Seas, Marine Life Must Swim Faster, Study Finds
Sea life, particularly in the Indian Ocean, the Western and Eastern Pacific and the subarctic oceans, will face growing pressures to adapt or relocate to escape extinction, according to a study by an international team of scientists published in Science.

Using 50 years of data of global temperature change, the researchers analyzed shifting climates and seasonal patterns to understand how rising ocean temperatures will affect life over the coming century. Under global warming, land animals and plants are migrating polewards at a rate of about 6 kilometers a decade. As a general rule, however, it seems sea life will have to move a lot faster and farther to keep up with temperature shifts in the oceans, the research found.

"Unlike land-dwelling animals, which can just move up a mountain to find a cooler place to live, a sea creature may have to migrate several hundred kilometers to find a new home where the water temperature, seasonal conditions and food supply all suit it," said John Pandolfi of the ARC Centre of Excellence for Coral Reef Studies and the University of Queensland.

The migration is likely to be particularly pronounced among marine species living at or near the sea surface, or subsisting on marine plants and plankton that require sunlight, and less so in the deep oceans.

At the same time, sea life living close to the poles could find itself overwhelmed by marine migrants moving in from warmer regions in search of cool water. The team's future research will focus on how different ocean species respond to climate change, and the scientists are compiling a database on this for the Intergovernmental Panel on Climate Change. For more information, visit www.sciencemag.org.


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