Well, I would say that is the answer. I could look deeper into the matter, but I doubt I would find much. The Rabbis are probably even now formulating answers. I suspect those answers have to do with the copepods not being properly "food", any more than gelatin is food. Although in the USA, American koshrus groups do not give kosher labels to anything except gelatin made from kosher animals and vegetable matter, in some countries, gelatin of any sort (even made from pigs) is considered edible because by the time it gets to the consumer, gelatin is considered to be a non-food item. In other words, although it is passable through the digestion, it serves no legitimate purpose as food.
For example, a rock is neither kosher nor non-kosher. You can eat it if you wish, though I never met anyone that wanted to. In some countries, gelatin is classified as neither kosher nor non-kosher. You may eat it or not, just like a rock. In the USA, it is classified as a food, and therefore is subject to the kosher laws (in which case it has to come from a kosher animal or from plants. If it comes from a pig it is not kosher and cannot be eaten by Jews. In this country most gelatin comes from either cows or pigs, but no one knows which, therefore it is not kosher).
In the case of the water, since, like the gelatin, there is no value food-wise to the copepod, the Rabbis might just declare it NOT to be a food. Just like a rock, it might be edible, or like gelatin in some countries, where it has been ruled a non-food item. You can eat it or not as you choose.
To a non-Jew, this kind of formulation might not make sense, but to us it makes perfect sense. A food, to a Jew, is something that provides calories and nutrients. A rock does not do this. Gelatin does not do this, at least not in significant amounts. (Jell-o might, I don't know what else is in the stuff). Copepods do not do this, at least not in significant amounts (a whale has to eat a SHIT-ton of the stuff, I am guessing, to get any value out of it).
Now, I don't KNOW that that is the argument that the Rabbis will use. I am just guessing that they might. Or they might come up with something totally different. Just a thought.