It was formerly urged against trawling that it was very destructive to the spawn, at that time supposed to be lying on the sea bottom. But the investigations of the late Professor Sars, for the Swedish Government, into the spawning habits of sea fish, have conclusively revealed the fact that the ova of fish float on the surface of the water during the whole period of their development. Not only have the floating ova of the cod and haddock been reared, but the common plaice, the representative of the flatfish family, including the brill, the sole, and the turbot, is also known to spawn near the surface. The eggs of the mackerel and the garfish have likewise been found floating, and successfully hatched. Now, no fish comes so close to the land as does the mackerel, yet it is certain that it never makes its way into the estuaries and inlets till after spawning is finished--for that it spawns in the open sea is almost without a doubt. These facts consequently do away altogether with the old statements concerning the destructive results of trawling. The yield from the English trawleries alone is computed to be over 200,000 tons annually, and as the price for trawled fish at the Billingsgate market averages 12 pounds per ton, this represents about two and a half million pounds. And, in addition to these weighty figures, Professor Huxley's words deserve to be well remembered, for, says he, "Were trawl fishing stopped, it would no longer be a case of high prices, but that ninety-nine out of a hundred would hardly be able to afford any at all--herrings and a few other fish caught in the old way excepted." Indeed, it is chiefly by this method of beam trawling that London and the interior are supplied with brill, turbot, and soles; while by it thousands of tons of plaice, haddock, and other fish are brought within the reach even of the poorest. DRIFT-NET AND OTHER DEEP-SEA FISHING. Important though the beam-trawl may be, there is another mode of deep-sea fishing which deserves to be well known by us in Australia, and which undoubtedly must come into general use before we can make any pretensions with regard to our fisheries. I refer to that by means of drift-nets. As the trawl is absolutely necessary, on the one hand, for capturing fish which frequent the bottom, so, on the other, the drift-net is essential for those whose resort is the upper portion of the sea. It is by this method alone that fish like the herring, the mackerel, and the pilchard--which may be termed surface fish--are caught in great quantities for food supply.