Automaton

Okay.
The article referenced never states that though. The ocean is not uniformly 5 miles deep, but in a 1x1x30380.6 foot^3 (assuming an international nautical mile) collumn, that would be .9 herring per square foot, which is pretty damn crowded.
Thanks for the rhetoric, but it misses the point. Some relevent figures would be nice, and it's always good practice to include them in a written article where mathematics-based conclusions are given, and it does only take into account surface.
They were feeding on magical invisible pixie dust in the air and water. They always had the ability to eat normal food, but never had the instinct or inclination to do so, until all the pixie dust disappeared after the Flood.
Yeah, and...?
The article was talking about animal biomass, not plants.
God cast a spell that protected it before, during and after the flood (before it could fin suitable human hosts).
I don't need to, I didn't find faults with those part of the argument. I'm an atheist and accept the scientific model of the geological history of Earth.

Asha'man

Just a note about the distribution of life in the sea:

While the oceans are 3 dimensional, the livable area is not very deep. I would guess that 99% of all the biomass in the ocean lives within the first 1000 feet. That is where the sunlight is able to penetrate for the plants, and therefore where the food is for everything else.

I know about deep water scavangers and bottom dwellers in the deep, but I think they will easily fit into the last 1%.

ps418

Here's something I wrote about crinoids in the geologic record, along with a correction (I originally gave a vast underestimate). I have not tried to calculate how deep the crinoids would have to have been on the preflood earth, but obviously it would be very deep, and would leave no room for all the other stuff that would need to fit in somewhere (like the plants represented in the world's coal reserves).

Begin quote:

There are vast deposits of limestone (packstones) consisting >50% of crinoid elements ('regional encrinites'). According to Ausich et al. (In Hess et al., 1999), on the order of 10^13 - 10^16 crinoids are represented in such deposits (this does not include the crinoid material found outside of regional encrinites). The surface area of the earth is about 0.5 x 10^15m2. Assuming that there are 10^15 crinoids represented in the geologic record, and that crinoids were distributed equally across the globe before the flood, this works out to about 20 crinoids per m2.

CORRECTION:

This is incorrect. I misinterpreted a statement in Hess et al. (1999) which cites Ausich (1997). Now that I've read Ausich (1997), I see that he estimates that 10^15 - 5 x 10^16 crinoids are represented in the Lower Mississippian Burlington and Keokuk limestones of Iowa, Illinois, and Missouri alone (p.510). This does not include all of the other Mississippian regional encrinites, or those which occur in older and younger strata. Ausich (1997) writes:

Ausich (1997) notes that although these Mississippian examples are the most extensive examples of regional encrinites, other regional encrinites are present from the Ordovician to the Triassic. Examples cited (p. 513) include the Ordovician Holston Formation of Tennessee, the Silurian Brassfield Formation of Ohio and Kentucky, the Silurian Irondequoit, Gasport, and Wiarton formations of New York, Pennsylvania, and Ontario, the Devonian Coeymans, Keyser, and New Creek limestones of New York and West Virginia, the Devonian Sadler Ranch Formation of Nevada and California, the Devonian Edgecliff Member of the Onondaga Limestone, New York, the Triassic Lower Muschelkalk of Germany, and the Jurassic Smolegowa Limestone of Poland.

Ausich, W.I., 1997. Regional Encrinites: A Vanished Lithofacies. In Brett, C.E., and Baird, G.C., eds., Paleontological Events: Stratigraphic, Ecological, and Evolutionary Implications; Columbia Univ. Press, New York, pp. 509-519.

Hess, H., Ausich, W.I., Brett, C.E., and Simms, M.J., (eds.), 1999. Fossil Crinoids. Cambridge University Press, 275 pp.