Hake age and sex structure of catches landed. 1986-1998 period. During the 1986-1998 period the hake fishery turned from moderate to intense exploitation. Age and sex structure analysis showed a change in the exploitation pattern. During the three periods defined (1986-1989, 1990-1992 and 1993-1998) a trend towards catching young individuals and a predominance of females age 3 and older was observed. An increase of total mortality was also detected. As a consequence of the establishment of a closed area in mid 1997 ice-chilling and freezer fleets changed operation areas which brought about differences in the catch structure. Freezers showed higher percentages of older ages. An average decrease of 30% in yield (number of individuals por unit of effort) for all ages was also observed.