THE Ministry of Agriculture and Fisheries Report on the Salmon and Freshwater Fisheries for the year 1930 brings to our notice that that year was characterised throughout Great Britain by the marked shortage of salmon from our rivers. Furthermore, this had followed on from a shortage that was already apparent in 1929. In both years it was the four-year-old fish which failed to come up to number, which indicates that for some reason the smolt crop of two successive seasons, in 1927 and 1928, has not returned from the sea. All available evidence goes to show no reason that would cause the smolt run from the rivers to the sea in those years to have been a failure, and one is left to conjecture that “unfavourable factors in the sea caused the destruction of the main body of smolts which descended”. With most of our food fish from the sea, the abundance of future stocks is probably determined at a very early stage of the fish's life—during the first year at any rate, as shown by the successive predomination of one-year's stock from year to year in the catches. It is easy to imagine factors which may bring about heavy mortality when the fish are at a young and delicate stage, or that may even curtail spawning efforts; but the salmon are already sturdy grown fish by the time they enter the sea, and, barring excessive depredation by enemies, it is difficult to suggest a reason for their non-return.