Animal of the Week July 11, 2005 -- Fish-eating jelly-fish

Hola Animalistas,

Hope everyone is OK, and my sincerest condolences, thoughts, and good wishes to anyone who, for whatever reason, is not.
So, AOTW will now resume normal service for the foreseeable future, fulfilling the promise of its moniker by weekly delivery.
This week's animal of the week, Erenna sp, is all over the science news but probably wont cross over to general media. This newly discovered deep-sea species belonging to the same phylum (Cnidaria) as jellyfish, corals, and anemones is attracting media attention with the red fluorescent organs it uses to lure prey. Few creatures that live at great ocean depth can see red light because light with longer wavelength travels poorly through water, hence throughout evolution predatory animals at depth have lost the ability to see red light and prey animals have developed red pigmentation. However, some canny (not canned) fish have cottoned onto this fact and realised that over small distances myriad red animals stick out, quite literally, like sore thumbs (although this simile is wasted on fish) and make easy pickings. Now, this as yet unnamed species of the genus Erenna exploits the fact that some small fish hunt out the red light omitted by their prey copepods. With their red fluorescence they trick fish into thinking they are a tasty bite of tiny crustacean, when it turns out they're in reality a baguette sized bundle of stinging cells and venom. Neat!

And the best thing about the whole story is that the chief researcher is a marine biologist called Dr Steven Haddock.