Studies of spatial ecology of demersal sharks are critical to understanding the significance of habitat variation; however, limited information exists. Spatial ecology of adult Heterodontus portusjacksoni was studied at three locations on the central and southern coast of New South Wales, Australia, from January 2002 to December 2005. Juveniles within a nursery area were studied from December 2002 to December 2005. Tag-recapture, day and night underwater visual census, and acoustic tagging were used. Adults returned annually to the same coastal breeding reefs for up to four consecutive years. Individual juveniles resided within a sea-grass nursery area for at least 2 yr and were not uniformly distributed throughout the nursery. Adult females often sheltered in aggregations in gutters as a male avoidance strategy, and both sexes utilized the sand/reef interface in the absence of gutters. Juveniles aggregated infrequently due to absence of habitat features that mediated aggregation. Acoustic tracks of adults revealed periods of inactivity up to 27 hr. Juveniles spent significant amounts of time inactive, punctuated with short bouts of swimming. Juveniles utilized moderate activity spaces (3,510–583,990 m2) centered over a core area of the sea-grass bed but also ranged over much larger areas of the bay. Use of space by H. portusjacksoni is strongly influenced by habitat characteristics throughout its life history.
