ABSTRACT. Estuaries and associated seagrass habitats are thought to be important nursery areas for many fishes. There is, however, no direct evidence for movement of fish from estuaries to reefs. The alm of this study was to determine if populations of Achoerodus viridis (Labridae) on rocky reefs were sustained by (1) recruitment to estuarine seagrass habitat followed by m o \ i e~~~c n t to rocky reefs, (2) direct recruitment to rocky reefs, or (3) a combination of the two. Recruits were collected from estuarine seagrass and rocky reef habitats and elements in their otoliths analysed by inductively coupled plasmamass spectrometry (ICP-MS) to determine if d~fferent 'elemental fingerprints' could be found. Higher concentrations of Zn, AI, Pb, Mn, Ba and CO were found in otoliths of recruits from estuar~ne seagrass habitat than In otoliths of recruits from coastal reefs, the latter 3 elements showing sign~ficant differences. Strontium occurred in significantly h~g h e r concentrations in otoliths of recruits from coastal reefs. Differences in concentrations of some elements In the otoliths of recruits allo\ved fish from the 2 env~ronments to be dlstinyuished 1~1 t h a high degree of dccuracy, enabling the contribution of estuarine recruitment to sustaining reef populations to be determined. Elemental composition of the juvenile core of otoliths from adults on reefs was related to the composition of otoliths of recruits from each environment to identify historical recruitment environments. Discriminant function analysis showed that 41 % of adults had recruited to estuaries and 59%) had recruited to reefs, but these figures may be overestimated because adults must be assigned to 1 of the 2 groups. There was evidence to suggest that some adults may form a third intermediate group. Further validation (e.g. comparison w~t h laser or probe based methods and tagging techniques) of our a p p r o~~c h is warranted. Elemental techniques may have great potential for resolving fisheries problems and identifying broader scale effects of environmental degradation.

Fish were collected from localities in the Sydney region, New South Wales, Australia, from March 1991 to September 1993. Achoerodus viridis is a benthic carnivore and consumes a wide variety of prey items. Size-specific differences in diet were found. The diet of recruits (17-26 mm SL) collected in seagrass environments was dominated by tanaids, whereas that of rocky reef recruits was dominated by harpacticoid copepods. The diet of rocky reef fish then shifted to gammarid amphipods and other crustaceans (fish 50-150 mm SL) and to mussels and urchins (fish >300 mm SL). Juvenile fish on rocky reefs (450 mm SL) foraged in shallow fringing habitat, whereas adult fish (>200 mm SL) foraged in deeper turf and barrens habitats, reflecting the depth distribution of the species. Feeding rate of larger fish tended to be less than that of smaller fish. Variations in diet and feeding rate were also detected over the year but the patterns were not consistent between years. Among sites, there were differences in diet but these were not related to the position of sites inside an estuary or on the open coast. The results of this study provide information on the feeding ecology of a large labrid fish; this information will aid in understanding the population dynamics of the species.

Achoerodus viridis (Pisces : Labridae) was sampled over two years at Little Bay, NSW, Australia, and comparative material was taken from a site 4.5 km away at Cape Solander. Population structure and gonadal structure showed that A. viridis was protogynous and monandric (i.e. no primary males were found). Histological sections of male gonads showed a gonadal lumen, general ovarian lamellar form and multiple sperm ducts running longitudinally through the gonad wall. Males dominated the larger size and age classes, whereas females predominated in the smaller size and age classes. The sex ratio of mature fish and the whole population was biased in favour of females. Individuals at both sites matured as females at 1+-2+ years. Fish at Little Bay functioned as females at ages ranging from 8+ to 18+ years before changing sex at a size between 480 and 580 mm SL. Fish at Cape Solander may function as females for up to 18+' years and change sex between 500 and 520 mm SL. Spawning occurred between July and October (1991-93).

Patterns of abundance and size-frequency distributions of Achoerodus viridis (Pisces: Labridae) in the Sydney region (New South Wales, Australia) showed greater numbers of small fish (c200 mm standard length, SL) on estuarine reefs than on open coastal reefs. In contrast, open coastal reefs had greater densities of large fish (>200 mm SL).Growth of A. vlrld~s was therefore invest~gated to determine to what extent differences in size-frequency distributions between estuarine and open coastal reefs could be explained by slower growth at estuarine reefs compared to open coastal reefs. No significant differences in growth of A. viridis were found between estuarine and coastal reef sites. Spatial differences in me-frequency distributions are most likely due to movement of f~s h from estuarine to coastal reefs, rather than differences in growth of fish.