10. A possibility that has not yet been raised is that there may be aspects of the northern cod life-cycie and/or behavior that are density-dependent or age-structure-dependent. Below some critical value, mating behavior may not be triggered or fertilization may be erratic. Recent work by DFO scientist George Rose suggests an even more dire possibility. Using stateof-the-art hydro-acoustic technology, he tracked the inshore migrations of major concentrations of fish which were apparently lead by a few large old females IREFS?CFI. Rose's findings seem to indicate that cod have some sort of rudimentary culture --aspects of their annual round that are learned through inter-generational transmission. The assessment surveys show that what's left of the stock has a highly compressed and truncated age structure with the vast majority representing only two year-classes --1986 and 1987. The population may be starving to death or failing to reproduce successfully because there are not enough older fish left to teach the remainder the migration routes to the feeding and spawning grounds.