Dr. Ellen Pikitch:

One really needs to take at least annual measurements. There is a need for annual monitoring. Let me give some examples to show how it is done. I do not want to stick to one method only because some methods are better for certain species. For example, one method that is used a lot in the California current region involves looking at egg production because the species concerned produce a lot of eggs which tend to float to the surface. One can take a net and count the number of eggs produced. That gives one a pretty good idea of how many spawning fish there are. This method has been used a lot in the case of sardines off the Pacific coast of the United States. With some species, one can use acoustic methodologies which is a fairly straightforward way of looking at biomass over time. When one cannot use these methodologies, one must go with the standard fisheries assessment methods whereby one make some catches to get the age composition. One has to have a model to put it all together. These fish are more amenable to some of the acoustic and egg production methods than many other species. It actually could be easier to monitor them.