THE INCREASE IN SPAWNING BIOMASS OF NORTHERN ANCHOVY, ENGRAULIS MORDAX

The northern anchovy, Engraulis mordax, is a common fish off the west coast of North America. The various methods of deriving anchovy spawner biomass from the sardine spawner biomass and analogous census estimates of sardine and anchovy larvae are reviewed. A new compilation of anchovy and sardine larval data is presented for 1940, 1941, 1949, 1950, and 1951-69. The effect of several errors of estimate are examined and it is concluded that none is important enough to affect measurably the trend of increase between 1951 and 1966. Lastly, a current interpretation of the larval survey data is used to estimate the spawning biomass of both sardine and anchovy. Its biomass has increased markedly since 1951.