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In the 1960s there was a population explosion of Acanthaster and many marine
biologists feared they would do irreversible damage to the reefs. Many schemes
for reducing their numbers were devised, but the sea star soon returned to
normal numbers and the fear passed. Many hypotheses exist about the causes of
the population explosion, most of them citing human activity. Natural predators of
the Acanthaster include giant clam, grouper, painted shrimp, pufferhsh, triggerfish
, and ...
They were named "right whales" by commercial whalers because they float after
being harpooned and were therefore easily brought aboard ship. This
unfortunate characteristic lead to overhunting, which significantly reduced their
numbers. The blue whale is the largest animal ever known to have lived on the
earth, reaching lengths of 1 10 feet and weights of 100 tons. Depleted to near-
extinction by commercial whalers for their high yield of oil, the blue whales'
population has been ...
Living alone in the huge open sea, their chances of finding a mate are slim,
especially when one considers their small post-whaling population. Even before
they were hunted, the blue whales numbered only 100,000 worldwide, not a
large population. Although fully protected by the International Whaling
Commission, the blue whale is not, by any means, out of danger. All whales are
known for their effective means of communicating. The toothed whales
communicate by emitting from ...
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I purchased all three books in this set and taught a short course to a small group of high school kids. We had a great time with this course! We did 10 experiments and held very intense all-day ... Read full review