Kalkbreath":1kehc158 said:
Being that Im always way ahead of the game.......No scientists have come out and pointed to the sharks as the reason fish levels have plumited in certain areas of Florida or that having hundreds or thousands cruzing the beach shallows might be excessive.
A simple search yields:
Hundreds of sharks close Florida beaches
http://www.boston.com/news/nation/artic ... a_beaches/
Oh, sounds ominous. Until you realize that this happens EVERY SINGLE YEAR, and the only reason it *SEEMED* more pronounced this year was due to clearer than normal water, making them more visible than in more average years. Yes, they've also come in a bit more closer than average. And it would be pure speculation as to why.
Schools of sharks normal for Florida
http://www.sciencedaily.com/upi/index.p ... sharks.xml
Study: Sharks are essential to coral reefs
http://www.sciencedaily.com/upi/index.p ... sharks.xml
The central issue Kalk raises, that sharks are the reason why fish levels are getting lower and lower, is not supported by the evidence.
But getting to this means you have to leave the layman's media and delve into the journals - And I realize how unexciting this is.
http://www.pnas.org/cgi/reprint/102/15/5443
(May not work from outside, Reference
www.pnas.orgcgidoi10.1073pnas.0501562102
PNAS April 12, 2005 vol. 102 no. 15 5443–5447)
Interaction strength combinations and the overfishing
of a marine food web
Jordi Bascompte*†, Carlos J. Melia´ n*, and Enric Sala‡
Goes on to show how removal of top-level predators leads to reef degradation. A combination of factors in the Carribean has led to the reef degradation there. Removal by overfishing of most of the herbivorous fish led directly to one species becoming the dominant herbivore, the Diadema sea urchin. After a bacteria disease basically wiped this species out, reefs have gone progressively from coral-dominated to algal dominated reefs. Algal dominated reefs do not support the same kinds or levels of species.
So you had the trophic food web destroyed on the one end. Over the past few years (or probably decade now), sharks, the top level predator, have been decimated in much of the Carribean. The paper referenced above shows how this has some pretty massive effects downward and across the trophic food web. Vitz was right, attacking the top and bottom of the food web is a bad idea, and the entire Carribean ecosystem has shifted across the board.
A normal, yearly migration of sharks does not mean the numbers have gone up drastically overall. There is no evidence to support the existence of more sharks than normal. And the evidence that does exist shows the opposite of Kalk's assertion to be true - that lower shark numbers are a leading cause of undesirable trophic cascades, ones that lead to lower fish numbers and reef degradation.
Regards.
Mike Kirda