During 1963 and 1964, studies were conducted aboard the research vesselG.B.Reedto test schemes for sampling individual trawl catches of groundfish, principally Pacific ocean perch (Sebastodes alutus), for size composition, weight and numbers caught, and sex ratio. A species sort into tub lots preceded sampling. Empirical tests were used to evaluate sampling methods for all parameters except sex ratio. Size composition and sex ratio samples were evaluated with chi-square tests. Estimates of weight and numbers caught were arbitrarily evaluated on the basis of their percentage deviations from actual values.For ocean perch the size composition, weight caught, numbers caught, and sex ratio were best estimated from a stratified sample consisting of the first 2, middle 2, and last 2 full tubs weighed. For 21 test hauls, the error range for weight estimates was −6 to +5%; for estimated numbers caught, −5 to +4%. Sex ratio was homogeneous among tubs within hauls.For six other groundfish species, weight caught was satisfactorily estimated from a serial sample consisting of the first 6 full tubs weighed, providing the tubs within hauls were filled uniformly. For 13 tests, the error range was −3 to +1%.