Jellyfish and Turtles

[Myra]

Did the hurricane at least get rid of the Jelly fish in GTC? I have never seen so many as we did this summer. We were told it was a bad sign for the turtles. Anyone care to elaborate?

[Keyscaptain]

HI M

Craig Q. of Reef Relief and I discussed the abundance of moon jellyfish relative to the decrease in the turtle population.

Craig recalled a day a decade or so back when he and his wife were cruising off S America in the midst of a migration of 1000's of turtles. He doesn't remember so many jellyfish back then.

Its hard to not justify his theory that a lot more turtles would likely mean a lot less jellyfish.

Turtle anyone?

adam

[ranno]

Turtles eat Jellyfish. A part of there diet along with crustaceans

Ron

[PELLUCID]

The prime factor in moon jelly populations is food supply:
http://plankt.oupjournals.org/cgi/content/abstract/20/5/805

Hurricane Agnes caused a noticable reduction in the sea nettle population of Chesapeake Bay in 1972, have no idea whether this would affect moon jellies or not:
http://www.mdsg.umd.edu/MarineNotes/Jul-Aug94/side1.html
http://www.intercom.net/local/shore_journal/jp010716.html

Moon jelly population explosions in the northern Gulf of Mexico have been variously blamed on fertilizer runoff and the habitat provided by oil rigs:
http://www.eurocbc.org/page727.html

The leatherback turtle is the only sea turtle which eats jellyfish and related animals almost exclusively. Some estimates indicate that these turtles eat their weigh in jellyfish every day. HOWEVER -- while the decline in nesting leatherback females from 115,000 (1980) to 34,500 (1995) is nothing short of alarming, it is impossible for such a small number of predators to have a significant impact on the billions of jellyfish produced in a summer bloom:
http://www.sararegistry.gc.ca/status/showASCII_e.cfm?ocid=177