In a number of previous reports observations on the seasonal abundance of the pelagic young of teleostean fish in the plankton off Plymouth have been recorded for the years 1924 to 1938 inclusive. Owing to the outbreak of war the series for the year 1939 is unfortunately not complete. Collections were, however, made until the last week in August. Previous records have always shown that the numbers of young fish caught in the last four months of the year, September to December, are insignificant and in consequence it is desirable that the results for 1939 should be published since they cover fully the period of production of almost all species of fish. It is, also, essential that these records should not be lost as the year 1939 has been the worst yet recorded and sets a new low limit to the production of fish. It is much to be deplored that the sequence of observations may be broken, so that we may never know what point the trough of the decline may reach.