Wednesday, July 07, 2004

A History of Copepods

What's the deal with copepods? Did Chazal know about them? Did they drink their water not knowing of copepods, or did they know of them and drink their water anyway?
Or, did they not have copepods? Or, did they have copepods and therefore did not drink the water unless it was filtered?]

This post will be a work in progress for a while, since there is much to write.

Aristotle and copepods
The first to discuss copepods in scientific literature was Aristotle. In his book History of Animals, chapter 19 (about sea fish), Aristotle writes:

The tunny {J: = tuna} and the sword-fish are infested with a parasite about the rising of the Dog-star; that is to say, about this time both these fishes have a grub beside their fins that is nicknamed the 'gadfly'. It resembles the scorpion in shape, and is about the size of the spider. So acute is the pain it inflicts that the sword-fish will often leap as high out of the water as a dolphin; in fact, it sometimes leaps over the bulwarks of a vessel and falls back on the deck. The tunny delights more than any other fish in the heat of the sun. It will burrow for warmth in the sand in shallow waters near to shore, or will, because it is warm, disport itself on the surface of the sea.

A picture of a little tunny Posted by Hello

A picture of a swordfish Posted by Hello

Image of cyclops copepod
From the website:
Cyclops are crustaceans and related to lobsters, crabs and shrimp. They are invertebrates with a hard outer shell. They swim freely about.
The cyclops has 5 pair of legs and a divided tail-like appendage called a furca. The Cyclops is very small about 2-3mm long with one black or red eye in the middle of its head. The cyclops is named after the one-eyed monster of Greek legend. It is greenish, straw yellow, or grayish in color. It goes jerking through the water usually in very large numbers. The females carry the eggs (shown in picture) in little side sacs and they multiply rapidly. The cyclops is often seen near water fleas or Daphnia. Many water animals feed upon the cyclops. It has a very important role in the food chain.
 Posted by Hello


fairly large copepod parasites infesting frshwater and saltwater fish. most likely noticed by fisherman fairly early.

parasitic and non-parasitic (free-living) copepods.

freshwater Cyclops is non-parasitic.
Panella (parasitic copepod)
nearly every aqautic animal has copepod parasites.
Aristotle (384-322 BCE)
presumably fishermen brought them to his attention.
"It is a fact that this parasite copepod is found with a certain frequency on tuna and always near the fins, thus it would seem strange and could easily have excited the imagination of the first observers. It was only natural that Aristotle credited this animal with the form of a scorpion, maintaining the notion of discomfort to the host. Because of the parasite's varied extremities, caudal appendages, and egg sacs resembling feet, these could be thought of as sucking organs. It is admirable that Aristotle compared its size to that of a spider, and did not compare it to "insects" other than scorpions based on its external aspect. On the other hand, it had some characteristics of a worm, since Aristotle used the term "vermiculum." There were arguments much later that perhaps this parasite was an isopod, rather than a copepod, but the notation "worm," together with the other descriptive points, place it with the copepods. This uncertainly by Aristotle is hardly surprising, considering that even into the 1800s, zoologists were undecided about placing these organisms with insects, crustaceans, worms, or mollusks, or even into a separate group." (The Copepodologist's Cabinet)

Pliny the Elder (23-79 CE)
basically restates what Aristotle wrote.
"The animal is small, looks like a scorpion, has the size of a spider. When the tuna and the swordfish are crowded together even more than dolphins, this is fastened at a points under the fins and inflicts so much dicomfort, that the often jump into the boats. They run as one fearing the whip, so fast that they jump shaking across the boat."

Image of Sirius, the dog star Posted by Hello

Image of a scorpion Posted by Hello

Update: Johan Christian Lange, in 1756, published a book, in which he "surveyed Copenhagen's drinking water. He published drawings of three "water-fleas" (a Cyclops species), one of which was carrying egg-sacs... As advice to his readers, Lange suggested that they use a bag of hat felt to filter the "fish" (all the small creatures) and plants from the water before drinking, or, if desired, they could "enjoy a soup of them if the water was boiled." (The Copepodologist's Cabinet, pg 35-36)

i need to arrange much of the above material.
there is a difference between parasitic and free-moving copepods, with the former being larger and thus discussed first (by Aristotle, Pliny, etc.)

to be continued in this post...

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