Conservation programs for breeding ducks in North America are typically designed to enhance nest success by establishing or restoring attractive perennial nesting cover or promoting favourable agricultural practices. Thus, a central objective is to attract ducks to habitats where females have higher survival and reproductive rates, primarily greater nest success. Using data collected from 1993 – 2000, I investigated hypotheses proposed to explain inconsistent patterns of habitat selection detected during nesting and brood–rearing stages in free-ranging mallards (Anas platyrhynchos) throughout the Canadian Prairie Parklands. By simultaneously considering indices of body condition and size of male and female mallards and plumage score of males, I also evaluated the role of male quality in reproductive investment and patterns of breeding success of females. In general, wild mallards mated assortatively by body condition but not body size. Yearling females nested earlier and had higher nest survival when mated to males with better plumage quality. When paired with larger-bodied males, yearling females renested more often, whereas nest and brood survival increased among older females. I characterized the habitat composition of 100 and 500 m radius buffers surrounding nest sites and related habitat features to survival of nests, broods and females. Habitat selection trade-offs were detected among perennial habitats and planted cover, such that nest survival increased in these habitats whereas duckling survival decreased. Furthermore, at large spatial scales, nest survival decreased in areas with greater amounts of cropland whereas duckling survival increased. Survival rates of females increased with greater amounts of seasonal wetlands, but nest survival decreased in such areas. Semi-permanent wetlands were associated with decreased nest survival at larger spatial scales, but associated with higher nest success at finer scales. Benefits of increasing perennial and planted cover habitats to increase nest survival could be partly offset by costs in terms of lower duckling survival, whereas opposite patterns existed in areas of abundant seasonal. The restoration of seasonal wetlands in perennial habitats could offset these trade-offs but net impacts of habitat selection and survival trade-offs on annual reproductive success must first be evaluated.

Within the latitude of a science-fictional elsewhere and elsewhen, women can establish their own social norms and accepted praxis. The modification encountered in alternate feminist spacetimes specifically incorporate many new ideologies concerning motherhood. Central to this discussion is the means by which feminist authors regard the influences of patriarchal institutions and the subsequent changes in society because of, or in spite of, these changes. The male-dominated fields of technological patriarchy (reproduction and fertility "specialists") and the military, for example, are areas upon which feminist authors speculate. Three feminist strategies for coping with a patriarchal social order, as seen in the works of science-fiction, are entrance into the male world and attempts to change it, competition in the patriarchal world on its own terms and total retreat from an oppressive society, accompanied by the creation of a feminist utopian otherworld. These feminist spacetimes share a number of convictions. Most important, conception is never an unwilled experience. The "maternal instinct", is redefined as a calling which, in some cases, extends to males and non-biological mothers. Traits that are salient in the childraisers are those which are mirrored by these alternate feminist spacetimes as a whole and which contribute to the definition of these societies as utopias. The treatment and/or possession of children as property is frowned upon in the novels. Some points of dissent amongst feminist SF authors include the existence of technology in an utopian or dystopian future for motherhood, and whether or not males are permitted and/or encouraged to participate in society as a whole and more precisely in the experience of mothering. The dystopia, for its part, can thus be regarded as a warning against the encroachment of rampant patriarchal enterprises through their representation of the extrapolation of male-centred value systems. (Abstract shortened by UMI.)

In the last three decades regulation as a public policy instrument has developed from a tool to manage markets to a means for government to offer protection or impose boundaries in areas associated with social and moral issues. Social regulatory mechanisms are broad, and have as their justification the public interest. It is one response by governments to the development of reproductive technologies. (For complete abstract open document)

What determines parenthood? The advent of IVF and the rapid growth of reproductive technologies have challenged the significance historically associated with biological relationships. It is now possible for a child to have many different people in the role of genetic, gestational, nurturing or legal parent and for the formation of many novel types of families. While frequently some or all of these roles are combined, it is now possible for someone to be a ‘parent’ in one sense, without necessarily taking on the obligations and rights associated with parenthood in a moral sense. Despite the expanded options for constructing families and the proliferation of novel arrangements for raising children, the essential feature of what it means to be a ‘real parent’ and to have a child of ‘one’s own’ is often grounded in the transmission of genes. This thesis examines the claim that genes define ‘moral’ parenthood. It investigates whether or not genetic relatedness is morally weighty in determining which individuals incur obligations for and rights over children. My thesis adopts a novel approach to address this question. It combines the analysis of both people’s views as captured through a qualitative study and those found in philosophical literature relating to the moral significance of genetic parenthood. I design and conduct a study to capture more directly the meanings that people attach to passing on their genes, which acts as a starting point for identifying and evaluating possible arguments about the moral relevance of genetic parenthood. I then analyse the principles imbedded in the participants’ views in light of the current philosophical literature.

Cambodian youth live in a country undergoing rapid development and modernization. The srey kalip or modern women of Phnom Penh are an emerging demographic group of young urban females driving social change in the context of globalization. Despite their obvious presence in society, very little is known about this growing demographic and even less is known about their sexual behavior. This research employed a range of ethnographic methodologies in order to capture one essence of Phnom Penh’s modern women—their reproductive health seeking behavior. The results of this study indicate that the adoption of a modern identity has changed constructions of traditional Khmer femininity. This introduced “liberalism” challenges traditional ideas about what it means to be a Khmer woman and what it means to be a sexual woman. The srey kalip’s sexual and reproductive health needs present a much broader profile than the existing health system is capable of providing for. The availability of existing sexual and reproductive health services does not dovetail with their modern identity. This inability to acquire adequate reproductive health care is a consequence of the disjunction between the srey kalip’s modern identity and a less modern health system. The tension between the modern and traditional body are drawn into focus when the srey kalip seek medical care for reproductive health services and are unable to obtain care that meets their unique needs. This is not a problem restricted to Cambodia. Many developing nations around the world have populations of urban youth who are more globally interconnected and more modern than their parent’s generation. Ministries of Health and health service providers around the world need to develop innovative and dynamic strategies to meet the sexual health needs of their burgeoning modern youth populations. The opportunity to meet the sexual and reproductive health needs of youth is a task that Ministries of Health around the world cannot afford to waste.

Research Doctorate - Doctor of Philosophy (PhD) / In temperate New South Wales, most fish species in the family Labridae have not previously been investigated with available knowledge restricted primarily to photographic identification guides providing brief notes on species distribution, habitat preferences and identification. This information is inadequate for assessing the impact of labrid harvesting on rocky reef systems and for making informed management decisions for the protection of these fishes. Therefore, this study aimed to fill some of the significant gaps in the understanding of labrid assemblages associated with rocky reefs of temperate eastern Australia. This was accomplished by concentrating primarily on three species - Ophthalmolepis lineolatus, Notolabrus gymnogenis and Pictilabrus laticlavius - which are abundant and co-occur in shallow waters (less than 20 m depth) on the central coast of New South Wales. The methods used in this study included SCUBA surveys of labrid assemblages; in situ observations of labrid behaviour on SCUBA; and acquisition of labrid specimens for the extraction of intestines, gonads and otoliths, and for measurements of fish weight and length. <br /> Labrids were found to be the most species rich family in the study region and were the most abundant of all non-planktivorous fishes. Overall, a higher number of labrid species and a higher number of labrid individuals occurred in sponge garden habitat (15-22 m depth) compared to fringe (3-7 m) and barrens (8-15 m), owing to greater densities of O. lineolatus, Austrolabrus gymnogenis and Eupetrichthyes angustipes. The common labrids, N. gymnogenis, Achoerodus viridis and P. laticlavius, occurred at higher densities in fringe habitat due mostly to a higher representation of juveniles in this habitat. The effect of habitat on labrid assemblages was subject to small-scale variation between sites (separated by hundreds of metres) and experienced temporal changes due primarily to a substantial increase in the abundance of recruits coinciding with late summer and autumn (April-May). Behavioural observations revealed that the three focal species differed substantially in their spatial structure. O. lineolatus were found to be temporary reef residents using home ranges in excess of 2500 m2 for periods of up to 1 year before permanently emigrating outside these temporary home ranges. In contrast, N. gymnogenis exhibit strong site fidelity to reef patches of less than 600 m2 in which they remain for periods in excess of 2 years. Reef patches are shared by up to at least 10 juvenile and female individuals and a single, highly territorial male in a mating system suggestive of resource defence polygyny. An understanding of the spatial structure of P. laticlavius was constrained by its cryptic behaviour, but behavioural observations suggest this species is home ranging and establishes temporary territories for the purpose of feeding and/or reproduction. Intensive ethological observations allowed for the description and quantifying of several major behaviours in which all species typically engaged including encounters and interactions with other fishes, lying, use of shelter, side-swiping, bending, gaping, cleaning by clingfishes (Gobiesocidae) and colour change. The occurrence of these behaviours often demonstrated substantial differences among species (e.g. lying, shelter and bending) and/or experienced shifts with ontogeny (e.g. interactions and area usage). These trends generally remained consistent at different times of the day and periods of the year, and at both locations. Dietary analyses revealed O. lineolatus, N. gymnogenis and P. laticlavius are generalist carnivores feeding on a variety of benthic invertebrates including polychaetes, amphipods, decapods, gastropods, bivalves, polyplacophorans, echinoderms and cirripedes. Differences in the volumetric contribution of prey items in the guts of each species showed that food resources are partitioned among species and observations of foraging behaviour demonstrated a partitioning of microhabitats used for feeding. Ontogenetic shifts in diet and feeding microhabitats demonstrate that food resources are further partitioned within a species. However, overall morphological and behavioural similarities within a species results in greater competition occurring among individuals of the same species than among individuals of different species. This was reflected in higher rates of intra-specific interactions compared with interactions between labrid individuals of different species. Observations of feeding episodes revealed the bite rates of all species were typically unaffected by the time of day and period of year in which sampling occurred, but a location effect occurred for O. lineolatus and P. laticlavius. A reduction in bite rate with ontogeny occurred for N. gymnogenis. The population structure of the three species suggests each exhibits the typical labrid reproductive strategy of protogynous hermaphroditism. O. lineolatus and N. gymnogenis are both monandrous species, but the occurrence of some P. laticlavius males at small sizes and young ages suggests this species may be diandrous. Similarities occurred between O. lineolatus and N. gymnogenis in the size/age at which individuals sexually matured (c.a. 180 mm, 2 years) and changed sex (c.a. 280 mm, 4.6 years), but these events occurred at substantially smaller sizes (95 and 138 mm, respectively) and younger ages (les than 0.9 and 1.9 years, respectively) in P. laticlavius. Sectioned otoliths were used to determine that the longevity of O. lineolatus, N. gymnogenis and P. laticlavius was at least 13.4, 9.6 and 4.8 years, respectively. Ages were validated using marginal increment analysis. Timing of reproduction in each species was asynchronous with peaks in the reproductive activity occurring in late summer to early autumn (February-March) for O. lineolatus, mid winter (July) for N. gymnogenis and mid spring to early summer (October-December) in P. laticlavius.

There has been an increase in reports of male reproductive disorders that include male infertility and testicular cancer worldwide. It has been suggested that agents such as xenoestrogens could be responsible. Xenoestrogens are chemical compounds that mimic the action of estrogens by binding to the estrogen receptors (ERs). The response ofa testicular cell line to estrogenic pesticides was examined. The effect of estrogenic pesticides on the growth and protein levels of ERα and ERβ of mouse Sertoli cells was investigated. Pyrethroids are widely used insecticides due to their insecticidal potency and low mammalian toxicity. In this study, the estrogenicity ofpyrethroid chemicals were tested using the yeast estrogen screen (YES) assay. The toxic effects of the pyrethroid compounds cypermethrin, 3-(4-hydroxy-phenoxy)benzyl alcohol (metabolite of permethrin), and the commercial product (Ripcord Plus) were evaluated. The Sertoli cells were exposed to pyrethroids at concentrations of 0.36 nM and 36 µM (cypermethrin and Ripcord Plus), and 0.69 nM and 69 µM (metabolite) for 100 h. The expression of the ERs was analysed through the use of Enzyme Linked ImmunoSorbent Assay (ELISA) experiments. The most toxic pyrethroid was the metabolite, followed by Ripcord Plus then cypermethrin. Overall the exposure of the cells to cypermethrin (36 µM), Ripcord Plus (36 µM) and the metabolite (69 µM) caused a significant decrease (p<0.05) in ERα levels. In the cultures exposed to the metabolite (69 µM), there was also a significant increase in ERβ levels. There appears to be a relation between cell toxicity and an increase in ERβ levels, which supports the theory that ERβ promotes apoptosis. Pyrethroids are rapidly excreted from the body, and it is unknown if there is accumulation in the male testes. Male fertility could be affected through molecular mechanisms involving the ERs, should cells in the male testes be exposed to these pyrethroids at physiologically relevant concentrations.

Many species have suffered severe range contractions as a result of human impacts, and require careful management if they are to persist. An understanding of the ecology, population structure and mating system is important for the conservation of these endangered species. Translocation has become a widely used tool in the conservation of threatened species; however, without proper planning and monitoring, many programmes end in failure. The bridled nailtail wallaby is one of the most endangered macropods in Australia, having suffered an extensive range contraction from the semi-arid region of eastern Australia to a single remnant population of ~ 500 animals at Taunton National Park in Queensland. In 1996, a translocated population of bridled nailtail wallabies was established at Idalia National Park, on the western edge of the former range of this species. The aims of this study were to: 1) determine the factors underlying variation in reproductive success among animals released at Idalia; 2) investigate the effects of a range decline on the genetic variation and population structure of the remnant population at Taunton; 3) assess the impact of captive breeding and translocation on the genetic diversity and structure of the established population at Idalia; and 4) investigate male and female mating strategies in this species. Chapter two investigated reproductive success among males released at Idalia National Park. The bridled nailtail wallaby is a sexually dimorphic, polygynous species and there is a large amount of variation in male reproductive success. Animals of different origin were released, including animals bred in captivity off the park, animals bred on-site in enclosures, and wild-caught animals from the remnant population that were moved directly to Idalia. There was significant variation in reproductive success among males released, but the origin of those animals did not explain this variation. Instead, large males were the most reproductively successful regardless of origin. Survival probability and release location were also important factors. This study highlighted the importance of considering mating system when choosing animals for translocation and suggests that, for polygynous species, a greater proportion of females and males of high breeding potential should be released. In Chapter three I investigated the genetic diversity and fine-scale genetic structure of the remnant population at Taunton. This last remaining population has been isolated for at least 60 years, corresponding to 30 generations for this species. Animals are patchily distributed in assemblages of different size that cover ~ 10% of suitable habitat on the park. Genetic diversity was surprisingly high within the population remnant and this species showed one of the highest levels of heterozygosity and allelic diversity of any macropod. The three sub-populations of animals sampled over 10 km were significantly differentiated, and fine-scale spatial genetic structure was also observed within a continuous sub-population of animals covering just 750 ha. Females were more related to each other than expected from random, whereas males were less related to each other than expected. Fine-scale genetic structure was observed among females but not males, providing evidence for female philopatry and male-biased dispersal. I suggest that fine-scale population structure and restricted gene flow among females but not males may maintain genetic diversity in this remnant population. Chapter four assessed the effect of translocation of animals of different origin on genetic diversity in bridled nailtail wallabies. Both wild-caught and captive-bred animals were initially released, but subsequent releases consisted of captive-bred animals only. In this study, I compared genetic diversity of released animals to animals sampled in the remnant population. Heterozygosity did not differ between the remnant and translocated population, however allelic diversity was significantly reduced among all groups released. Animals bred in captivity were significantly differentiated from the source population, whereas animals moved directly from Taunton were not. Releasing more captive-bred animals into the population after the initial release resulted in a decline in overall heterozygosity and allelic diversity. This study highlights the importance of sourcing animals directly from remnant populations in order to maintain genetic diversity and minimize genetic drift between source and recipient populations. The bridled nailtail wallaby has a polygynous mating system and reproductive success is skewed toward large males. However unlike most polygynous, sexually dimorphic macropods, the bridled nailtail wallaby is highly solitary; animals only associate to breed and males do not form stable dominance hierarchies. In Chapter five I investigated behavioural strategies used by males to secure matings, and mate choice among females. I found that males of different size adopted different mating strategies. Large males spent more time guarding females against other males and maintaining contact with them, whereas smaller males spent less time with guarded females in order to search for other females in oestrus. Females also preferred larger males and were more likely to engage in mate chases if there was a large number of males within the group.

The biology of four species of Choerodon (Labridae), the blue tuskfish C. cyanodus, the bluespotted tuskfish C. cauteroma, the baldchin groper C. rubescens and the blackspot tuskfish C. schoenleinii was studied in Shark Bay in Western Australia. These species are fished commercially and/or recreationally in this large subtropical marine embayment, which is a world heritage area. The biology of C. rubescens was also studied in the Abrolhos Islands, which are located ~ 300 km to the south of Shark Bay, where this labrid is an important commercial and recreational fish species. The broad aims of this project were to determine the following for the above four Choerodon species in Shark Bay. (1) Whether they are protogynous hermaphrodites, as is the case with many labrids. (2) The biological variables required for developing management plans for these species, such as the timing of spawning, the lengths and ages at both maturity and sex change, size and age compositions and growth parameters, and (3) the habitat types occupied during their life cycles and also of the purple tuskfish Choerodon cephalotes. Finally, comparisons are made between the age and size compositions, growth and reproductive biology of C. rubescens in Shark Bay and the Abrolhos Islands. Where relevant, the underlying hypotheses for the individual studies conducted during this PhD are included in the following chapters. A macroscopic and histological examination of the gonads of the full size range of C. cyanodus, C. cauteroma, C. rubescens and C. schoenleinii, together with an analysis of the length and age compositions of female, transitional (individuals changing sex) and male individuals, demonstrated that each of these species is a protogynous hermaphrodite, i.e. individuals change sex from female to male during their life cycle. The gonads of all small (< ca 100 mm) and young (< ca 1 year old) individuals of each species comprised solely ovarian tissue and thus the individuals of each species began life as a female. All individuals subsequently become sexually mature as females and then later in life some will change to males. Since this was found to be the only method of sex change in these species, they are termed monandric. Individuals that were changing sex contained “undelimited type 2” gonads sensu Sadovy and Shapiro (1987). These gonads contained both ovarian and testicular tissue that was intermixed and not separated by connective tissue. The males of each species possessed secondary testes, which retained structures of the ovary they had replaced, such as a membrane-lined ovarian lumen, lamellae and ovary wall. Furthermore, histological sections indicated that sperm were transported towards the outer walls of the testes, where the multiple sperm sinuses present in that region were presumably responsible for transporting sperm to the cloaca, rather than to a singular sperm duct as is the case with gonochoristic species. The typically large size and different colour of the males of C. rubescens, C. schoenleinii and C. cauteroma and the bias in the sex ratios of their adults towards females suggests that the males of each of these species are either haremic, i.e. permanently territorial, or form leks, i.e. are temporarily territorial during their spawning seasons. In these three species, the presence of ripe testes that are far smaller than ripe ovaries and the release by females of eggs in batches are consistent with a single male spawning with an individual female, as commonly occurs in haremic/lekking species. In contrast to the above species, C. cyanodus was not sexually dichromatic, the sex ratio was not biased towards either sex and the weight of ripe testes remained relatively constant as body weight increased. The latter implies that the relative investment of energy by males into testicular development during the spawning season declines with increasing fish size. Thus, the males of C. cyanodus may be opportunistic spawners when small, possibly spawning in groups, and may tend towards a haremic or lek mode of life when larger. The respective lengths and ages at which 50% of the females of C. cyanodus C. cauteroma and C. schoenleinii attained sexual maturity (L50m, A50m) in Shark Bay were ca 129, 196 and 253 mm and 2.3, 2.0 and 3.5 years of age. The corresponding L50m and A50m for C. rubescens in Shark Bay and the Abrolhos Islands were ca 274 and 279 mm, respectively, and 2.7 and 4.1 years of age, respectively. The respective lengths and ages at which 50% of the females of C. cyanodus, C. cauteroma and C. schoenleinii changed to males (L50c, A50c) in Shark Bay were 221, 310 and 556 mm and 4.1, 6.4 and 10.4 years of age. The length at which C. rubescens changed sex (L50c) was significantly greater in Shark Bay (545 mm) than in the Abrolhos Islands (479 mm), whereas the reverse pertained with respect to the age at sex change (A50c), i.e. 10.5 vs 11.9 years of age. Since some females were found in the oldest age classes of each species in Shark Bay and in the population of C. rubescens in the Abrolhos Islands, some of the females of each species do not apparently change sex. The trends exhibited by the gonadosomatic indices of females and males and the stages of ovarian development in sequential months demonstrated that the spawning periods of each species varied. Thus, C. rubescens (in both Shark Bay and the Abrolhos Islands) and C. cauteroma spawn predominantly in spring, whereas spawning occurs in late spring/early summer in C. schoenleinii and in summer in C. cyanodus. As C. schoenleinii, C. cyanodus and C. cauteroma occur predominantly within the inner gulfs of Shark Bay, the offset in the timing of their spawning periods would be likely to reduce any potential for competition between the larvae of those three species for resources. The trends exhibited by the mean monthly marginal increments in sectioned otoliths with differing numbers of opaque zones demonstrated that, in each species, those opaque zones were laid down annually. Thus, the numbers of opaque zones in the sectioned otoliths of individuals of each species could be used, in conjunction with the birth date and time of year when those zones are delineated, to determine their approximate ages at capture. The maximum ages recorded for the four Choerodon species in Shark Bay ranged only from 12 to 16 years. However, in that environment, the maximum lengths of C. rubescens (649 mm) and C. schoenleinii (805 mm) were far greater than those of C. cauteroma (424 mm) and C. cyanodus (382 mm). In contrast to the situation with C. rubescens in Shark Bay, this species reached a substantially older maximum age (22 years), but slightly shorter length (629 mm), and grew at a slower rate in the Abrolhos Islands, possibly reflecting the influence of greater productivity in Shark Bay and/or greater densities of this species in the Abrolhos Islands. Although a few C. rubescens and C. schoenleinii reach large sizes in Shark Bay, most of the individuals of these species were less than 400 mm, their minimum legal length (MLL) for capture. This raises the possibility that these two sought after species, i.e. the seventh and ninth most abundant species in the recreational fishery in Shark Bay, are subjected to substantial fishing pressure. Sampling for C. cyanodus was considered representative of the sites that this species occupies in Shark Bay and the sampling methods would have been likely to have captured the full size range of this tuskfish. Thus, the failure to catch any C. cyanodus greater than 400 mm indicates that, in Shark Bay, this species does not grow to the far greater lengths of about 600 mm reported for this species as a maximum by Allen (1999). Furthermore, the 400 mm MLL for this species in Western Australia precludes the retention by fishers of this species in this environment. Choerodon cauteroma was caught at lengths up to 424 mm, which is greater than the maximum of 360 mm reported for this species (Allen, 1999). Although there is no MLL for C. cauteroma, recreational fishers are restricted to a bag limit of four fish per person per day, as is the case with all other tuskfish species. Since fishers target large fish preferentially and the largest size classes of each of the species of tuskfish are dominated by males, heavy fishing pressure has the potential to remove a large proportion of the males of the Choerodon species that are fished in Shark Bay, i.e. C. rubescens, C. schoenleinii and C. cauteroma, and also of C. rubescens in the Abrolhos Islands. Since the ratio of females to males in catches of C. rubescens taken by the commercial fishery in the Abrolhos Islands are ca 1:1 and yet the typical adult sex ratio is heavily biased towards females (ca 14:1), that fishery is removing a substantial proportion of the males from the population. Protogynous hermaphroditic species are apparently able to respond to such pressure on the males by initiating a change in sex by the larger females. However, there is evidence from studies of other protogynous species that heavy size-selective fishing can lead to a reduction in the size and age at which a species changes sex and ultimately to a collapse in the stock. The results of visual surveys, when taken in conjunction with the locations of the catches of each of the five Choerodon species, demonstrated that C. rubescens lives on reefs in “oceanic” waters along the western boundary of Shark Bay, whereas C. schoenleinii, C. cyanodus, C. cauteroma and C. cephalotes are found predominantly in the two inner gulfs of this large embayment. Choerodon cephalotes lives almost exclusively in seagrass beds, while C. schoenleinii and C. cyanodus occupy predominantly inner gulf reefs and rocky shorelines and C. cauteroma occurs in all of those three habitats. Choerodon cauteroma was the only species that underwent an obvious size-related shift during its life cycle, moving from seagrass to hard substrates, such as inner gulf reefs and rocky shorelines, as it reached adulthood. The biological and habitat data produced during this thesis will provide fisheries and environmental managers with the types of information that will enable them to develop management plans for conserving tuskfish species and their habitats in Shark Bay. The biological data for C. rubescens in the Abrolhos Islands will be able likewise to be used to develop plans for conserving the stock of this species in waters in which it is heavily fished.

Research Doctorate - Doctor of Philosophy (PhD) / In temperate New South Wales, most fish species in the family Labridae have not previously been investigated with available knowledge restricted primarily to photographic identification guides providing brief notes on species distribution, habitat preferences and identification. This information is inadequate for assessing the impact of labrid harvesting on rocky reef systems and for making informed management decisions for the protection of these fishes. Therefore, this study aimed to fill some of the significant gaps in the understanding of labrid assemblages associated with rocky reefs of temperate eastern Australia. This was accomplished by concentrating primarily on three species - Ophthalmolepis lineolatus, Notolabrus gymnogenis and Pictilabrus laticlavius - which are abundant and co-occur in shallow waters (less than 20 m depth) on the central coast of New South Wales. The methods used in this study included SCUBA surveys of labrid assemblages; in situ observations of labrid behaviour on SCUBA; and acquisition of labrid specimens for the extraction of intestines, gonads and otoliths, and for measurements of fish weight and length. <br /> Labrids were found to be the most species rich family in the study region and were the most abundant of all non-planktivorous fishes. Overall, a higher number of labrid species and a higher number of labrid individuals occurred in sponge garden habitat (15-22 m depth) compared to fringe (3-7 m) and barrens (8-15 m), owing to greater densities of O. lineolatus, Austrolabrus gymnogenis and Eupetrichthyes angustipes. The common labrids, N. gymnogenis, Achoerodus viridis and P. laticlavius, occurred at higher densities in fringe habitat due mostly to a higher representation of juveniles in this habitat. The effect of habitat on labrid assemblages was subject to small-scale variation between sites (separated by hundreds of metres) and experienced temporal changes due primarily to a substantial increase in the abundance of recruits coinciding with late summer and autumn (April-May). Behavioural observations revealed that the three focal species differed substantially in their spatial structure. O. lineolatus were found to be temporary reef residents using home ranges in excess of 2500 m2 for periods of up to 1 year before permanently emigrating outside these temporary home ranges. In contrast, N. gymnogenis exhibit strong site fidelity to reef patches of less than 600 m2 in which they remain for periods in excess of 2 years. Reef patches are shared by up to at least 10 juvenile and female individuals and a single, highly territorial male in a mating system suggestive of resource defence polygyny. An understanding of the spatial structure of P. laticlavius was constrained by its cryptic behaviour, but behavioural observations suggest this species is home ranging and establishes temporary territories for the purpose of feeding and/or reproduction. Intensive ethological observations allowed for the description and quantifying of several major behaviours in which all species typically engaged including encounters and interactions with other fishes, lying, use of shelter, side-swiping, bending, gaping, cleaning by clingfishes (Gobiesocidae) and colour change. The occurrence of these behaviours often demonstrated substantial differences among species (e.g. lying, shelter and bending) and/or experienced shifts with ontogeny (e.g. interactions and area usage). These trends generally remained consistent at different times of the day and periods of the year, and at both locations. Dietary analyses revealed O. lineolatus, N. gymnogenis and P. laticlavius are generalist carnivores feeding on a variety of benthic invertebrates including polychaetes, amphipods, decapods, gastropods, bivalves, polyplacophorans, echinoderms and cirripedes. Differences in the volumetric contribution of prey items in the guts of each species showed that food resources are partitioned among species and observations of foraging behaviour demonstrated a partitioning of microhabitats used for feeding. Ontogenetic shifts in diet and feeding microhabitats demonstrate that food resources are further partitioned within a species. However, overall morphological and behavioural similarities within a species results in greater competition occurring among individuals of the same species than among individuals of different species. This was reflected in higher rates of intra-specific interactions compared with interactions between labrid individuals of different species. Observations of feeding episodes revealed the bite rates of all species were typically unaffected by the time of day and period of year in which sampling occurred, but a location effect occurred for O. lineolatus and P. laticlavius. A reduction in bite rate with ontogeny occurred for N. gymnogenis. The population structure of the three species suggests each exhibits the typical labrid reproductive strategy of protogynous hermaphroditism. O. lineolatus and N. gymnogenis are both monandrous species, but the occurrence of some P. laticlavius males at small sizes and young ages suggests this species may be diandrous. Similarities occurred between O. lineolatus and N. gymnogenis in the size/age at which individuals sexually matured (c.a. 180 mm, 2 years) and changed sex (c.a. 280 mm, 4.6 years), but these events occurred at substantially smaller sizes (95 and 138 mm, respectively) and younger ages (les than 0.9 and 1.9 years, respectively) in P. laticlavius. Sectioned otoliths were used to determine that the longevity of O. lineolatus, N. gymnogenis and P. laticlavius was at least 13.4, 9.6 and 4.8 years, respectively. Ages were validated using marginal increment analysis. Timing of reproduction in each species was asynchronous with peaks in the reproductive activity occurring in late summer to early autumn (February-March) for O. lineolatus, mid winter (July) for N. gymnogenis and mid spring to early summer (October-December) in P. laticlavius.