Social insects have complex forms of social organization. Molecular mechanisms involved in the regulation of their reproduction are not fully understood. This dissertation investigated the vitellogenin receptor (VgR), short neuropeptide F (sNPF) receptor, and two insulin receptors (InRs) in the red imported fire ant Solenopsis invicta, focusing on their possible roles in the regulation of queen reproduction. Knowledge of these receptors may provide novel ways to manipulate either reproductive castes or overall reproductive outcome, diminishing the fire ant impact as invasive pest. Fire ant virgin queens have more abundant VgR (SiVgR) transcripts than newly-mated queens, but limited egg formation. To elucidate whether queen maturation involved changes in SiVgR expression, we investigated both virgin and mated queens. In both queens, immunofluorescence analysis of ovaries revealed differential SiVgR localization in early and late stage oocytes; however, mated queens showed higher SiVgR expression than virgin queens. In virgin queens, the SiVgR signal was first observed at the oocyte membrane beginning at day 12 post-emergence, coinciding with the maturation period required before a mating flight. SiVgR silencing in virgins through RNA interference abolished egg formation, demonstrating that SiVgR is involved in queen ovarian development pre-mating. The sNPF and insulin signaling pathways have been implicated in the regulation of food intake and body size, and these peptides also play a gonadotropic role in the ovaries of some insect species. To elucidate the sites of action of the sNPF peptide(s), the sNPF receptor tissue expression and cellular localization were analyzed in the queen brain, subesophageal ganglion (SEG), and ovaries by immunofluorescence. Results suggest that the sNPF signaling cascade may be involved in diverse functions, and the sNPF peptide(s) may act in the brain and SEG as neurotransmitter(s) or neuromodulator(s), and in the ovaries as neurohormone(s). In addition, to elucidate the role of insulin signaling pathway in the fire ant, two putative InRs were cloned. Transcriptional expression analyses show that the receptor abundance was negatively correlated with body size and nutrition status in fire ant immatures. In queens, the expression of InRs in different queen tissues correlates with tissue requirements for queen reproductive physiology and behaviors.

Managed honey bee colonies face severe winter losses in northern climates. In my studies, interactions between genotypes of bees (genetically selected stock and unselected stock) with different levels of resistance and tolerance to varroa mites were assessed under a variety of treatment combinations to quantify effects of queen pheromone, acaricide treatment, wintering method, ventilation condition and pathogen infection on the costs and benefits associated with mite removal and mite-tolerance behaviors. In most of the experiments, mite-resistance caused greater varroa mite mortality within selected stock relative to unselected stock. Artificial and natural sources of queen pheromone caused greater varroa mite mortality within honey bee colonies relative to queenless colonies. While mite resistance had significant benefits, I showed that when producers selected colonies containing some mite resistance traits, it was traits associated with mite-tolerance and not mite-resistance were maintained and contributed to wintering success. Tolerance was effective at two levels of mites as obtained by late autumn treatment of colonies with oxalic but treatment did not improve wintering performance of either stock. Selected stock showed greater colony size, survival and resulted in more viable colonies in spring in comparison to unselected stock with similar initial mite levels (0.16 mites per bee). Selected stock showed greater relative wintering success than unselected stock when wintered indoors than when wintered outdoors but indoor wintering improved colony survival in both stocks relative to outdoor wintering. Carbon dioxide level increased within the winter bee cluster when colonies were maintained under restricted-ventilation (mean 3.82±0.031%, range 0.43-8.44%) and restricted ventilation increased mite mortality by 138% relative to standard-ventilation (mean 1.29±0.031%, range 0.09-5.26%), but restricted-ventilation did not affect bee mortality in comparison to standard-ventilation. In a laboratory study, I showed that Nosema inoculation (with co-infections of N. ceranae and N. apis) suppressed the effectiveness of mite removal behavior within selected bees relative to unselected bees. N. ceranae was more abundant than N. apis. Bees with greater mite removal capacities had higher costs associated with varroa-resistance as indicated by greater bee mortality rates when inoculated with varroa but bee mortality was not affected in Nosema inoculated bees.

This study investigates the contribution of including local stakeholders in the early stages of identifying local attributes of vulnerability, adaptive capacity and resiliency to climate change impacts. The research is specific to two remote coastal communities on Haida Gwaii (The Queen Charlotte Islands), British Columbia. It includes community feedback on research tools, as well as on local attributes of vulnerability and adaptive capacity. I employ multiple methods and a participatory approach for data collection. Using this approach I discovered that some of the attributes I originally believed contributed to vulnerability were perceived by participants as strengthening their community. Other attributes which I believed to be strengthening, were viewed by participants as contributing to vulnerability. This thesis illustrates how the use of multiple methods and a participatory approach contribute to greater knowledge and understanding, by both the researcher and the community, of local attributes of vulnerability and adaptive capacity to projected climate change impacts.

Descent with modification (Darwin, 1859) overwhelmingly occurs through the process of natural selection on genetically variable traits. Following deglaciation in the Pleistocene, morphologically conservative marine stickleback (Gasterosteus aculeatus) from two distinct mitochondrial DNA lineages colonized freshwater habitats on the Haida Gwaii archipelago. These freshwater populations have radiated in response to a diverse selective landscape on the archipelago and exhibit morphological diversity that equals or exceeds the known range for the species in the circumboreal distribution. I investigated the body shape of 3808 stickleback from 125 isolated populations from Haida Gwaii using geometric morphometrics. Relative warp and discriminant function analysis were used to quantify lateral shape differences based on partial warp scores. which were generated from twelve homologous landmarks digitally placed on each specimen's image. The possibility of ontogenetic shifts and sexual dimorphism of body shape were examined for each population on the archipelago. Stickleback body-shape changes during ontogeny were highly variable, and cannot be predicted by the volume and water clarity of the habitat. I found a slight sexual dimorphism in adult body shape, the magnitude of which could not be predicted by habitat volume and clarity. A number of comparisons were made to elucidate the possible causes for selection for divergence of adult body shape among Haida Gwaii populations. Body shape of parapatric lake-river stickleback populations differed significantly in concordance with hydrodynamic principles. Comparing the body shape of Haida Gwaii populations to the shape of sympatric benthic-limnetic species pairs from southwestern British Columbia. I found that benthic and limnetic body-shape ecotypes differ by up to 56% of the total variation among Haida Gwaii populations. Tests for phenotypic plasticity of body shape were conducted with two morphologically distinct stickleback populations that had been transplanted into two separate experimental ponds that were the ecological opposites of the respective source lakes. I found evidence for some phenotypic plasticity in body shape; the difference between each source and experimental population was approximately 11% of the total variation in body shape among populations throughout the archipelago. Throughout the islands adult body shape and size can be predicted by both abiotic and biotic factors of the habitat. Populations with derived shape (CV1+), including thicker peduncles, posteriad and closely spaced dorsal spines, anteriad pelvis, short dorsal and anal fins, and smaller body size occur in small, shallow, stained ponds, and populations with less derived shape (CVI-). with smaller narrow peduncles. anteriad and widely spaced dorsal spines. posteriad pelvis. longer dorsal and anal fins, and larger size occur in large, deep. clear lakes. There were large-bodied populations with derived shape (CV2-). including smaller heads and shallower elongate bodies in open water habitats of low productivity, and populations with smaller size and less derived shape (CV2±), with larger heads and deeper bodies, in higher productivity, structurally complex habitats. Populations with robust defensive adaptations have less derived shape (CV1-) and larger size, in response to salmonid predation, while populations with weak defences had derived shape (CV 1+), in response to bird/invertebrate predators. The ecomorphological relationships were consistent between mitochondrial lineages and replicated in each geographical region on the archipelago among geographically distant populations, suggesting the parallel evolution of body shape governed by the hydrodynamic constraints of each habitat. Although initially colonized by ancestors with conserved morphology, the stickleback populations on Haida Gwaii exhibit body shapes suited to the hydrodynamic landscape of the habitat, demonstrating the predictability of natural selection in adaptive radiations.

I analyse the emergence of a co-management system for protected area governance at Gwaii Haanas National Park Reserve and Haida Heritage Site on the northwest coast of Canada. Of primary concern is the analysis of the co-management structure for properties that are essential for maintaining a sustainable trajectory and an exploration of the key mechanisms for its development. The underlying framework for the analysis in this thesis is panarchy which is based on four categories of factors for building resilience: 1) learning to live with change and uncertainty; 2) nurturing diversity for re-organization and renewal; 3) combining different kinds of knowledge; and 4) creating opportunity for self-organization. This framework emerges from the conclusions of a multi-year team study of the dynamics of socio-ecological systems and how to enhance the resilience of these complex systems to tackle complexity, uncertainty and global environmental change. As the Archipelago Management Board (AMB) is the institutional structure that is managing the future of Gwaii Haanas, therefore, I focus on how this structure facilitates resilience. 1 argue that it should be an arena for flexible collaboration with multi-level governance that facilitates adaptive management (learning and building ecological knowledge into the institutional structure) and nurturing elements of resilience (cultural and ecological memory). The Lyell Island blockade in 1986, was a collective action against a crisis (cultural and environmental degradation caused by industrial logging) where key stewards and several Haida elders provided leadership, vision and trust. Parks Canada helped end the conflict by offering a management approach that accommodates Haida rights to their traditional lands, the formation of Gwaii Haanas National Park Reserve and Haida Heritage Site. Here I argue that the power-sharing structure of the AMB provides political space for experimentation. As such, the AMB appears to be an adaptive co-management system that is flexible, community-based, tailored to specific situations and supported by and working in collaboration with a concerned government agency to ensure sustainable resource management. So far, this arrangement has been able to successfully move away from a less desired trajectory toward a more sustainable one with the capacity to nurture the ecological health of Gwaii Haanas and the Haida culture on which it depends. I discuss the key role of co-management in re-coupling society to ecological feedback, creating political space for experimentation, accommodating varied ways of knowing and learning, including traditional ecological knowledge to link management with ecological understanding, and extending management into the social domain. I conclude that management in the implementation of protected area policy in Canadian National Parks could benefit from a more explicit collaboration with local communities who have special interests and site-specific ecological knowledge to better understand and monitor complex systems for long-term sustainability of protected areas.

Tectonic processes and seismic hazard along the west coast of British Columbia result from oblique convergence between the continental North America plate and the oceanic Pacific and Juan de Fuca plates. This dissertation integrates seismic and geodetic techniques to examine the tectonic interaction along these plate boundaries. The Queen Charlotte Fault zone is the transpressive boundary between the North America and Pacific plates along the northwestern margin of British Columbia. Two models have been suggested for the accommodation of the -20 mm/yr of convergence along the fault boundary: (1) underthrusting; (2) internal crustal deformation. Strong evidence supporting an underthrusting model is provided in this dissertation by a teleseismic receiver function analysis that defines the underthrusting slab. Forward and inverse modelling techniques were applied to receiver function data calculated at two permanent and six temporary seismic stations within the Islands. The modelling reveals a --10 km thick low-velocity zone dipping eastward at 28° interpreted to be underthrusting oceanic crust. The oceanic crust. which may be anisotropic, is located beneath a thin (28 km) westward shallowing (10°) continental margin. The majority of seismicity along the Queen Charlotte Fault zone plots within the modelled underthrusting crust, suggesting that these earthquakes are occurring on faults that extend down into the slab or they might be intraslab events. None of the earthquakes within the Queen Charlotte Basin have occurred deep enough to be intraslab earthquakes. The Wadati-Benioff seismicity may be inhibited beneath the basin by the hot young oceanic crust or by the short distance of underthrusting. GPS measurements have been recorded within the Queen Charlotte Islands during 8 years of campaign surveys. The crustal velocity field derived from the GPS data indicates northward margin-oblique motion of 10-15 mm/yr. Comparisons of the observed velocities with elastic dislocation modelling showed that the majority of the transpressive Pacific/North America motion is accommodated along the locked Queen Charlotte Fault zone and thrust fault with the remaining plate motion taken up by north-northeast migration of the margin at rates of --6 mm/yr. The migration is also supported by the stress pattern derived from focal mechanisms. However. the GPS determined deformation rates are much greater than the rates estimated in the Queen Charlotte Basin from the seismicity catalogue. The extra shortening could be accommodated by large characteristic thrust earthquakes within the basin. The deformation rates estimated from the seismicity along the Queen Charlotte Fault zone are consistent with the relative Pacific/North America plate motion: however. the seismic moment released by thrust earthquakes along the fault is insufficient to account for the component of convergence. This suggests that large thrust earthquakes may occur along the plate boundary. An additional part of this dissertation involved constraining the rupture parameters of the Nisqually earthquake. a M 6.8 event which occurred on February 28. 2001 within the subducting Juan de Fuca slab at the Cascadia subduction zone. The fault parameters of the event were estimated from moment tensor solutions, and by comparing the surface displacements from GPS and InSAR data. with predictions from elastic deformation models. The results are in agreement with the earthquake mechanism from waveform analyses. but provide substantially stronger constraints.

Porphyra abbottiae Krishnamurthy (Rhodophyta) is an intertidal red alga harvested by a number of coastal First Nations in British Columbia. The Kwakwaka’wakw have a long history of harvesting P. abbottiae as food and medicine, reflected in the language, songs and stories of the Kwakwaka’wakw oral tradition. Harvesting and drying practices for this alga have undergone changes with the introduction of new technologies and a decrease in time available for seaweed harvesting. The adoption of timesaving equipment into the seaweed harvest has given harvesters the flexibility to work around constraints including work and school obligations, tides, long distances to harvesting sites, and unpredictable weather conditions. Harvesting and drying practices reflect a thorough understanding of the lifecycle, biology, and ecology of P. abbottiae. Timing of the harvest during the seasonal round optimizes the taste and texture of P. abbottiae fronds while avoiding the seaweed in its reproductive stage. Songs and taboos associated with the harvest promote safety and efficiency while harvesting the seaweed. Concerns about potential contamination of edible seaweed led to the second part of this research: testing for metal contamination. Inductively coupled plasma mass spectrometry analysis for selected metals and trace elements revealed the presence of arsenic, cadmium, lead, and mercury in Porphyra abbottiae sampled from the southern Queen Charlotte and Broughton Straits. Mercury concentrations fell below the detection limit of 0.01 ng/mL in 28 of 112 samples. Calcium was the most abundant element measured, averaging 1445 mg/kg dry seaweed. The remaining metals, in decreasing order of concentration, are: Fe>As>Zn>Mn>Cu>Cd>Pb>Cr>Co>Se>Hg. Copper-zinc (r=0.835) and copper-lead (r=0.948) concentrations are significantly correlated (p<0.05), suggesting selective uptake of these elements. PCA analysis suggests that the location of harvesting sites within specific water channels is influencing metal concentrations. Hazard quotients calculated using guidelines set by Health Canada and the World Health Organization revealed that, among the suite of elements surveyed, arsenic followed by cadmium ranked the highest in relative risk for consumers of P. abbottiae. An average 60 kg adult consumer can safely consume approximately 9.4 g dried seaweed per day and not exceed tolerable upper intake limit guidelines. In conclusion, Porphyra abbottiae can be eaten in moderation with minimal risk of chronic metal contamination. Kwakwaka’wakw consumers can also benefit from cultural reconnection with this important traditional food. / Graduate

Despite recent interest in understanding long-term trends in ocean acidity, natural variations of carbon chemistry on short timescales are still poorly understood. Unfortunately, historical observations of the oceanic CO2 system are relatively few in number. Such data are particularly scarce along the highly productive Canadian Pacific coast. However, hydrographic data such as temperature, salinity, oxygen and nutrients have been collected regularly in this region. I developed a fully cross-validated statistical model to predict the aragonite saturation state (Ωarag), a biologically relevant measure of the carbonate system. Different sensitivity tests were performed to assess the robustness of the statistical modelling skill to different model structures. In particular, this study found that in situ temperature and O2 used together were strong predictors of Ωarag. The carbon data used to build this statistical model came from five hydrographic surveys along the Pacific coast of Canada (in July 1998, August 2004, late May 2007, February 2010 and early August 2010) that contain direct measurements of CO2 system parameters. Only data from a depth range of 0-750 m were used, as data from below 750 m showed biases due to calcium carbonate dissolution. Although processes such as solar warming and gas exchange occur in the surface and could possibly introduce biases in the model, I show that these surface data can be included. The ability of the statistical models to compute robust estimates of Ωarag was assessed by exploring the generalizability of the model through cross-validation procedures using different partitions of the data. By predicting lnΩarag rather than Ωarag directly, I obtained a strong and robust predictive relationship. This MLR model form yielded a high value in the squared correlation coefficient between predicted and observed values (0.96) and a low percentage in erroneous prediction of undersaturated conditions (3.1%). This relationship was found to be insensitive to changes in spatial domain or interannual variability in the data. These results suggest that the model can be used to estimate the distribution of Ωarag along the outer west coast of Canada when basic hydrographic data on temperature and O2 are available. Predictions of Ωarag from historical observations (1980-2009) in this region reveal that the saturation horizon (Ωarag=1) tended to be more stable in winter and spring and highly variable and occasionally shallow in summer and fall during and following the upwelling season. Undersaturation with respect to aragonite was more likely to occur at shallower depths over the shelf relative to adjacent offshore waters likely as a result of upwelling. The Ωarag saturation horizon tended to be more variable in depth on the shelf compared to offshore waters. The saturation horizon tended to occur at deeper depths over the Queen Charlotte Sound (QCS) shelf and be more stable with respect to the west coast of Vancouver island (WCVI). Thus, the WCVI may experience adverse effects of ocean acidification more acutely than QCS. The use of this approach may provide insight into natural variability and the key controls of Ωarag in future studies at a low cost. However, this predictive model cannot hind-cast data to evaluate the presence of the anthropogenic signal. / Graduate

The thesis focuses on four sets of official portraits of Queen Victoria and Prince Albert, which were painted by the German-born elite portrait specialist Franz Xaver Winterhalter (1805-1873) between 1842 and 1859. These portraits are examined in detail and are placed within the contexts of the existing scholarship on Franz Xaver Winterhalter, British portrait painting of the 1830s and 1840s, and the patronage of portraiture in Britain during the reigns of William IV and Queen Victoria. The thesis compares and contrasts these works with official representations of Queen Victoria and her husband by British artists; and examines the concept of “gender reversal” within the accepted notion of marital pendants by highlighting Winterhalter’s innovations in the genre of official portraiture.The thesis challenges the perception that Winterhalter’s employment at the court of Queen Victoria was due to the Queen’s alleged penchant for “all things German” by placing Winterhalter’s portraits within the context of the British Royal Collection. It examines the reasons for the artist’s success at the British court, accentuating among others Winterhalter’s ability to conceptualise in his portraits of Prince Albert the hierarchically-complex position of the Prince Consort. The overarching arguments of the thesis focus on two propositions - that by employing a foreign artist as her official image maker, Queen Victoria acquired ultimate control over the production, distribution and popularisation of her own imagery; and that this patronage is illustrative of the emergence of a royal and aristocratic international iconography that overrode the competing concept of ‘national’ schools of art.

The overall aim of this thesis was to determine the size and age compositions, growth and reproductive biology of Western Blue Groper (Achoerodus gouldii), Blue Morwong (Nemadactylus valenciennesi) and Yellowtail Flathead (Platycepahlus endrachtensis) in south-western Australian waters, in which these three species have divergent life cycle characteristics. As A. gouldii and N. valenciennesi are commercially and recreationally important in coastal waters and P. endrachtensis is one of the most recreationally important species in the Swan River Estuary, these biological data were then used to produce estimates of mortality and spawning stock biomass per recruit for each of these species. The biological data and stock assessment parameters were finally employed comparatively to ascertain whether any of the three species possessed characteristics that would make them particularly susceptible to the effects of fishing and whether there was evidence that any of the species is fully or even overexploited. Achoerodus gouldii typically uses reefs in protected inshore waters along the coast and around neighbouring islands as a nursery habitat and then, as it increases in size, moves to deeper, offshore reefs, where it spawns between early winter and mid-spring. The maximum total length and age of A. gouldii were 1162 mm and 70 years, the latter being the greatest age by far yet recorded for any species of labrid. However, most growth occurs in the first 20 years of life. Histological and demographic analyses demonstrated that all individuals begin life as females and, after attaining maturity, many become males, i.e. A. gouldii is a monandric protogynous hermaphrodite. The L50 at maturity and sex change were 653 and 821 mm, respectively, which correspond to ages of c. 17 and 37 years, respectively. As sex change took place over a narrower range in lengths (650 to 900 mm) than in ages (15 to 49 years), that change is apparently related more to size than age. Since sex change is typically accompanied by a change from green to blue, body colour can be used as a proxy for determining the length (L50) at which females change to males. von Bertalanffy growth curves fitted to the lengths at age of individuals of each sex of this hermaphroditic species using a novel technique demonstrated that, with increasing age, the lengths of males became increasingly greater than those of females. Thus, at ages 15, 30 and 60 years, the estimated lengths at age of females were c. 600, 670 and 680 mm, respectively, whereas those of males were c. 695, 895 and 975 mm, respectively. As A. gouldii is very long-lived and sexual maturity, and even more particularly sex change, occur late, this labrid is potentially very susceptible to overfishing. Thus, because the mortality estimates and per recruit analyses indicated that, at present, this species is close to or fully exploited, fisheries managers will need to take a precautionary and watchful approach to managing and thus conserving the stocks of this species. As with A. gouldii, N. valenciennesi moves to deeper, offshore waters as it increases in size and then matures and spawns in those waters. Although N. valenciennesi has a maximum length of nearly 1 m and thus, like A. gouldii, is moderately large, it has a far shorter life span, i.e. 19 vs 70 years. While female N. valenciennesi does not grow to as large a size as its males (max. lengths = 846 and 984 mm, respectively), the maximum age of both sexes was 19 years. From the growth curves, the females by ages 3, 6 and 10 years havd attained, on average, lengths of 435, 587 and 662 mm, respectively, compared with 446, 633 and 752 mm, respectively, for males. Both sexes grew little after 10 years of age. Juvenile N. valenciennesi < 400 mm in total length were found exclusively in shallow, coastal waters on the south coast, whereas their adults were abundant in offshore waters of both the south and lower west coasts. The females and males typically mature in offshore waters of the south coast at lengths of c. 600-800 mm and ages of c. 7-9 years. In contrast, the vast majority of females caught in offshore waters of the lower west coast (where they were of a similar length and age range to those in offshore waters on the south coast) became mature at lengths of 400-600 mm and 3-4 years of age. The attainment of maturity by N. valenciennesi at far lesser lengths and ages on the lower west coast than south coast suggests that the former coast provides better environmental conditions for the gonadal maturation and spawning of this species. Furthermore, the contrast between the almost total absence of the juveniles of N. valenciennesi in nearshore waters on the lower west coast and their substantial numbers in comparable waters on the south coast indicates that the larvae of this species produced on the lower west coast are transported southwards to the south coast, where they become juveniles. As spawning occurs between mid-summer and late autumn, the larvae, which spend a protracted period in the plankton, would be exposed, on the lower west coast, to the influence of the southwards-flowing Leeuwin Current at the time when that current is at its strongest. Although N. valenciennesi is caught by recreational line fishing and commercial gillnet fishing when they are as young as 3-4 years old, they do not become fully vulnerable to these fisheries until they are about 9 years old. Consequently, the individuals of this species can potentially breed over a number of years before they become particularly prone to capture by fishers. Mortality estimates and per recruit analyses suggested that N. valenciennesi in south-western Australia is not currently overfished. A greater resilience to fishing by N. valenciennesi than A. gouldii presumably reflects, in part, its far shorter lifespan, earlier maturity and possession of gonochorism rather than hermaphroditism. Platycephalus endrachtensis spawns in the Swan River Estuary between late spring and early autumn and completes the whole of its life cycle in this system. Although females attain a far larger length (615 mm) than males (374 mm), females and males were present in each age class. These data, together with a detailed examination of histological sections of a wide size and age range of individuals, demonstrated that this species, unlike some of its relatives, is not a protandrous hermaphrodite, i.e. it does not change from male to female with increasing body size. The combination of the presence of females and males in all age classes and the observation that all of the large number of individuals between 374 and 615 mm were females shows that the far greater length attained by that sex is largely related to its faster growth rate. The fact that females outnumbered males in each age class of P. endrachtensis in which the sample size was substantial, i.e. > 25, with the overall sex ratio being 2.7 females: 1 male, indicate that there has been strong selection for egg production in this species. As the minimum legal length for retention of P. endrachtensis is 300 mm, and relatively few males exceeded this length, the recreational fishery which targets this species is based largely on its females. The estimates of mortality and results of per recruit analyses provided no evidence that P. endrachtensis is currently overfished. From a management point of view, it is advantageous that the current size limit for this species exceeds the average length at which its females (259 mm) attain maturity. Furthermore, this species appears to be resilient to capture and release. The data presented in this thesis demonstrate that A. gouldii possesses biological characteristics which make it potentially more prone to the effects of fishing than is the case with either N. valenciennesi or P. endrachtensis. This presumably accounts, at least in part, for the indications that A. gouldii is the only one of these three species that is likely to be close to or at full exploitation.