A fast automatic new method, the "spray technique", for the separation of fish eggs from plankton samples has been developed; each egg-sorting procedure requires less than 3 min (removal of zero up to hundreds of eggs). A targeted accuracy can be achieved by repeating the procedure. The spray method can be easily applied onboard research vessels and it appears to cope well with different plankton compositions. Tests suggest that the method is 25, 60 and 110 times faster than the traditional manual method when using samples with low, medium and high plankton content. Sorted egg fractions contain less contamination by plankton particles than with the manual method. This new method is much less prone to human error and can be standardised. However, as plankton samples vary, it is crucial to estimate regularly the accuracy of the sorting. The method should only be used with standard operating procedures and pre-determined accuracy targets. Accuracy can be estimated afterwards by sorting thoroughly; checking whether any eggs had been left.