The Giant Manta, predator of the sea

Fish & Invertebrate sightings and descriptions, hosted by resident NWDC ID expert Janna Nichols (nwscubamom).
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maprn11
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The Giant Manta, predator of the sea

Post by maprn11 »

I was watching a short docu the other day, and there was a piece on the Giant Manta. The show said "The Giant Manta, predator of the sea". My question for everyone is, if an animal only eats plankton passively, meaning it doesn't hunt it's prey it just swim around with it's mouth open and eats whatever happens to be in the way, does that make that animal a predator? I say NO, what do you think?
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Greg Jensen
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Re: The Giant Manta, predator of the sea

Post by Greg Jensen »

I agree. Although strictly speaking the fact that it ingests larvae of various types (fish, crab, etc.) makes it a predator, it seems misleading to call it one. If you do, where do you draw the line? When a goat eats a plant with aphids on it, does that make it a predator?
Tidepool Geek
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Re: The Giant Manta, predator of the sea

Post by Tidepool Geek »

Greetings,

According to Wikipedia (if you can't trust them, who can you trust?):
"When foraging, it [the manta ray] slowly swims around its prey, herding it into a tight "ball" and then speeds through the bunched organisms with a wide-open mouth"
To me personally, that sounds like true predation.
Arguably, defining the term "predator" is an almost metaphysical experience:
At one extreme you've got Dr. Walter H. Adey referring to herbivores as "predators on plants" and at the other you've got things like cougars and great white sharks that target specific prey individuals.
How about baleen whales - Humpbacks use sophisticated 'herding' techniques to concentrate their food while Bowheads and Rights presumably do not but both are eating a pretty specific animal based diet. Is one more of a predator that the other?
Further, what can be made of an isopod (often a cirolanid) that will attack a much larger fish, eat its fill, and then drop off (often without killing the fish); then repeat the sequence the next time it's feeling hungry? Is it necessary to kill something to be a predator?

Philosophically yours,
Alex
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