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will be able to be carried out. In the deeper parts of the freshwaters, where the 
deposits are usually soft and the depths small, lighter bottom-samplers can certainly 
be used from small boats; if it is desired to use larger bottom-samplers from large 
ships such can probably be constructed quite easily. In the larger seas it is 
obvious that it would be an advantage to use large hottom-samplers, as at many 
places not many organisms will come into these; the reason why we our- 
selves have not 'felt it necessary to use larger is, that the small (0.1 m.?) are well 
suited for our fjords with their large number of small animals. 
We have here a new field of work, which is very large and seems 
promising. Enumeration of the bottom-animals does not take up so much time as 
counting of the plankton; and when the percentage of dry matter has been deter- 
mined for the different years, the number of individuals, as also the total rough 
weight of the species per 100 stations or fewer, will give good information regarding 
the mass of the animal life per m.? 
I am inclined to believe, that an evaluation with such bottom-samplers 
could be carried out comparatively easily, and would lead much further than 
plankton determinations alone can, in the direction of the determination of the 
mass of fish food. We may certainly with Hensen consider it a condito sine qua 
mon, that we must know on the main points the capacity of a water as regards 
the production of fish-nourishment, in order to be able to judge as to its rational 
exploitation in the interest of the fisheries. It will however scarcely be an easy 
matter to determine exactly, by quantitative investigation of the food- 
animals alone, the quantity of food available yearly, annual food-production, 
for the consumption of the fishes or other animals in any water; nor is it practi- 
cally possible in the case of the plankton; it is only the logical consequence 
of our scientific mode of working to attempt to do such a thing. Both 
Hensen and the present work endeavour therefore at the same time to find 
another, more direct way, namely, to determine the production of food by 
investigating, what is actually used of the food by fishes or other 
animals which have lived on this food. When we have determined in 
this way, how much å sea-bottom can produce, it is comparatively easy by means 
of the bottom-sampler to compare this bottom with another and thus obtain a 
good insight into, whether the one or the other is best suited for the production 
of the one or the other kind of food-animals, this or that species of fish, and 
whether on the whole it is more productive than the other. It is this I 
have in mind in using the expression ”valuation of the bottom”. The importance 
of such a valuation in the comparison of areas on land and in the whole practice 
of agriculture is well known; it is time we introduced similar methods in sea- 
culture. In the case of freshwater areas, one or several methods of valuation 
have been experimented with (Walter, Zuntz), with more or less success; that 
several important freshwater fishes take vegetable food as well as animal, compli- 
cates the conditions here a good deal; further the principal food-animals in fresh- 
water (Crustacea) seem to be very small and not specially bound to the bottom; 
enumeration and bottom-sampling are thus made difficult; it is much easier to 
count the plaice-food in the Limfjord. Perhaps the proper apparatus have not yet 
been found. I should be inclined to think, that suitable, modified forms of the 
