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horseshoe crab  (Source: web.rollins.edu)
Sea-level rise and ocean temperatures are affecting horseshoe crab breeding

New research from the U.S. Geological Survey (USGS) reveals that horseshoe crab populations may be declining due to changes in the climate

Horseshoe crabs are arthropods that have lived on the planet for approximately 450 million years. These ancient creatures have declined in population in more recent years, and the main reason is because of overharvesting (for fertilizer and bait) and coastal habitat destruction. But now, climate change may have some part in the dwindling numbers as well.

"Using genetic variation, we determined the trends between past and present population sizes of horseshoe crabs found that a clear decline in the number of horseshoe crabs has occurred that parallels climate change associated with the end of the last Ice Age," said Tim King, lead author of the study and a scientist with the USGS.

According to research by the USGS, accompanying water temperature fluctuations and sea-level rise have contributed to limited horseshoe crab interbreeding and distribution. This leads to a reduction in population, which is what happened when temperatures rose after the last Ice Age.  

Horseshoe crabs are not the only creatures affected by their decline, though. Migrating sea birds like the Red Knot depend on horseshoe crab eggs for food each spring. Red Knots usually eat horseshoe crab eggs at Delaware Bay during migration, but severe population declines in horseshoe crabs have occurred all along the eastern seaboard of the United States. Significant declines have also occurred in the eastern Gulf of Mexico. 

In addition, Atlantic loggerhead turtles have experienced a change in population due to the lack of adult horseshoe crabs in Chesapeake Bay. 

Now, conservation managers are using certain findings, such as the fact that adult male horseshoe crabs travel from bay to bay while females stay in one place, to create both local and regional strategies to help sustain the horseshoe crab populations, and help them to continue reproducing.  

"Consequently, harvest limitations on females in populations with low numbers may be a useful management strategy, as well as relocating females from adjacent bays to help restore certain populations," said King. "Both studies highlight the importance of considering both climatic change and other human-caused factors such as overharvest in understanding the population dynamics of this and other species."

This study was published in Molecular Ecology in August of this year.




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If I were as bad at my job . . .
By Denigrate on 9/3/2010 8:52:32 AM , Rating: 5
If I repeatedly performed at the low level shown by Ms. Kaiser, I would have been fired long ago.

It's sad how low the level of journalism has fallen at this once great website. If it continues to be so poor, I may have to cease my daily visits to Daily Tech.




RE: If I were as bad at my job . . .
By phxfreddy on 9/4/2010 12:27:13 AM , Rating: 5
This website long ago became "Monthly Tech" for me!


By nstott on 9/8/2010 9:55:59 AM , Rating: 2
My thoughts exactly. I hope Kris is paying attention.


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