A DAILY FECUNDITY REDUCTION METHOD OF BIOMASS ESTIMATION WITH APPLICATION TO DOVER SOLE MICROSTOMUS-PACIFICUS

A daily fecundity reduction method was applied to Microstomus pacificu s, commonly known as Dover sole, a pleuronectid flatfish of the upper continental slope (200 to 1,500 m) of the west coast of North America. This method was developed for estimating adult biomass of fishes with determinate annual fecundity and utilizes the daily decline in reprod uctive potential of the population and the numbers of planktonic eggs. Daily decline in reproductive potential was estimated from the declin e of the product of the standing stock of advanced oocytes and the num bers of females with reproductively active ovaries. Daily production o f planktonic eggs was estimated from the numbers of eggs in quantitati ve oblique plankton tows. We describe the survey design, data assembly , statistical estimation procedures, and the possible biases due to th e limitation of surveys.