138 The N.Z. Journal of Science and Technology. [May 
It is of interest to note that in 1916 fish-oil (exclusive of cod-liver oil, 
which can be made here) to the extent of 40,850 gallons, valued at £3,626 
(Is. 9d. per gallon), was imported into this country. On the other hand, 
of phosphatic manures (including blood-and-bone manure), no less than 
92,898 tons, valued at £324,548, were imported. The demand for fish- 
manure, which combines both phosphatic and nitrogenous materials, is 
therefore great, and there is room for a very considerable manufacture. 
Miscellaneous Aquatic Products. 
Under this heading Dr. Prince refers to several other substances obtain¬ 
able in one way or another from the sea, of which I would refer to three— 
viz., fish-roe, fish-powder, and kelp. 
Dr. Prince points out in his paper that there is great waste of roe or 
fish-eggs ; and this is as true of New Zealand as of Canada. A certain small 
trade is done in this direction in fresh roes, chiefly of warehou in the north 
and of groper in the south. These are only sold fresh ; but roes of fish pre¬ 
pared with a proportion of fat, salt, and spice, and either potted or tinned, make 
a most excellent and tasty food. At present these things are all wasted. 
Prepared roes of cod, haddock, and other well-known fish in northern waters 
are extensively used in the sardine industry in France. At present this is 
largely in abeyance, but there is no doubt that it will be revived again after 
the war. The eggs are used as bait, and are scattered on the surface of the 
water to attract the shoals of sardines. These roes appear to be essential to 
the success of the industry in France; and their scarcity is always a serious 
matter—curtailing the catch, reducing the income of the fishermen, and 
often producing distress among the fisherfolk. The French sardine fishery 
is absolutely dependent on this bait, and at the beginning of the century 
the importation into France amounted to from 40,000 to 45,000 barrels of 
salted roes, valued at about £60,000. 
Fish-powder for making soup, or a coarser form for feeding pigs or cattle, 
is largely made in some countries. For the latter purpose very inferior 
fishes, dried and powdered, prove to be a very fattening material. In the 
discussion which followed the reading of Dr. Prince’s paper Mr. Fielding 
made some remarks on this subject which I quote : “ Some ten or fifteen 
years ago I was engaged with Herr Jaffe, head of the German Hanoverian 
fisheries, in investigating methods of utilizing the fish-waste at Wilhelms- 
haven and other places in Germany. They have developed an enormous 
industry in the creation of fish-meal. I was the first man to take it up in 
England. It was a fish-food for fish-culture establishments. About fifteen 
years ago I recommended Dr. Hugh Smith and Mr. Ravenal, and two or 
three of the United States fish-culturists, to experiment with it, and I believe 
they did. The dog-biscuit manufacturers, including Spratt’s and other 
well-known firms, took it up. Then it was taken up by the pig-food manu¬ 
facturers to replace tankage. We know the cost of tankage in this country 
is very high, and the average farmer is rather frightened of it. Fish-meal 
can be put on the market a good deal cheaper, and, I think, is of the same 
if not higher protein value, and probably of better oil value. The possi¬ 
bility of its tainting the flesh has been urged, but I am rather inclined to 
think that it does not do so if properly mixed with other materials and 
treated only as a concentrate.” Later on the same gentleman said, 
“ There is a plant at Wick, in the north of Scotland, where they make a 
most agreeable foodstuff for human use called ‘ marvis.’ At one time it 
had a large market for making fish-soups and souffles, and anything you 
