Academic literature on the topic 'Golden perch'

Many freshwater fishes have been introduced outside their natural range. The consequences have included the decline or extinction of native fishes, principally due to competition and predation. Redfin perch (Perca fluviatilis) is a highly efficient predatory fish species that was introduced to Australia in the 1800s. It now has a broad distribution in the Murray–Darling Basin, but its impacts on native fishes are largely unstudied. It often cohabits with native golden perch (Macquaria ambigua ambigua), which is similar from a trophic ecomorphology perspective. We examine prey selection and diet overlap of adult redfin perch and golden perch under contrasting hydrological conditions in terminating lakes of the Murray–Darling Basin. Prey selection by both species varied substantially between drought and flood conditions. Diet overlap of redfin perch and golden perch was significant only during flood, and was apparently related to pelagic prey availability. There were dietary differences during drought that imply that resource partitioning occurred between the perches, possibly because competitive interactions were intensified. Conversely, the promotion of pelagic prey fishes during flooding apparently facilitated resource sharing. The findings suggest that redfin perch can directly compete with native piscivores for prey. The potential impacts on native piscivores and small-bodied fish populations warrant further experimental and field investigations.

Larval silver perch (Bidyanus bidyanus) and golden perch (Macquaria ambigua) were subjected to gradients of light, depth, flow and wood leachate from river red gum (Eucalyptus camaldulensis) as well as a control treatment with no gradient. Both species were strongly attracted to light, while golden perch larvae were also attracted to river red gum and were carried downstream by water flow. Neither species displayed any response to depth. Gradient responses of silver perch were significantly more variable (P < 0.05) than those of golden perch, which may result in silver perch larvae being more widely distributed in floodplain habitats. Golden perch larvae may be more closely associated with inundated river red gum than silver perch larvae.

Trials were conducted to evaluate coded wire tags for marking hatchery-produced golden perch and silver perch fingerlings prior to their release into the wild. Two size classes of fish were tagged: 'small' fish were 21-39 mm in total length and 'large' fish were 50-71 mm in total length. Tags were implanted into either the cheek muscle or the snout. Tagging rates were 200-548 fish h-1. Although tag retention in large cheek-tagged golden and silver perch was 100% after 30 days, rearing fish to this size was not practical. Retention rates for small cheek-tagged golden perch (94%) and silver perch (100%), the usual size of fingerlings when released to the wild, were considered to be sufficient for a tagging programme. Retention of tags in the snout was poor; only 6% of golden perch and 48% of silver perch retained tags after 30 days. Most cheek-implanted tags that were shed by fish during long-term tag-retention trials were lost in the first four months. With the exception of silver perch in one trial, which were infested by Ichthyophthirius multtfiliis, survival of tagged fish was 95-100% after 30 days. Factors affecting tag retention and survival of tagged fish, including fish size, tagging site and operator experience, are discussed. The results indicate that coded wire tags are a potential means of marking golden and silver perch fingerlings prior to stocking. Their use will assist fisheries managers in the assessment of the contribution of stocking programmes to commercial and recreational fisheries.

Fertilization of earthen ponds used to rear the larvae of golden perch, Macquaria ambigua, and silver perch, Bidyanus bidyanus, resulted in phytoplankton blooms dominated by the cyanobacterium Anabaena possibly because of a low N:P ratio. There was a zooplankton succession of rotifers (mostly Brachionus), Moina, Boeckella and Mesocyclops, and then Daphnia. An increase in Daphnia correlated with a decline in Anabaena, suggesting grazing on that cyanobacterium. Golden perch larvae included copepods in their diet whereas silver perch did not, and this was reflected in lower Boeckella numbers in the golden perch ponds. There was sufficient zooplankton forage, supplemented by chironomid larvae in the later stages of the rearing ponds, for fish growth. The limnological conditions and zooplankton communities in these ponds provide a model for evaluating nursery grounds for these fish.

Radio tagging and tracking are widely used to study freshwater fish; however, details of fish survival or tag retention rates are rarely reported. The results from five independent tagging trials associated with different tag attachment methods are reported in the present study. Implanted peritoneal cavity tags were trialled for two native Australia freshwater fish species (golden perch and silver perch) and introduced carp. Oesophageal and external tags were also trialled on silver perch. The results from the peritoneal cavity implantation trials in golden perch, silver perch and carp achieved an overall success rate of 81% (after 315 days), 18% (after 200 days) and 43% (after 323 days) respectively. The external attachment of radio tags to silver perch had limited success with all fish either rejecting their tags or dying before 256 days. Silver perch trialled with oesophageal tags had an overall success rate of 25% after 200 days. The trials indicate that internal tagging is suitable for longer-term radio tracking of golden perch, but further developments are required for longer-term applications to silver perch and carp. Tag rejection rates are unlikely to be constant between species or through time and this variability should be incorporated into the study design to prevent bias.

Effective fisheries management requires fish size, growth and mortality information representative of the population and location of interest. Golden perch Macquaria ambigua is long lived, potamodromous and widespread in the Murray–Darling Basin (MDB), Australia. Using a sample spanning 13 river systems and 10° of latitude, we examined whether the maximum size of golden perch differed by latitude and whether growth and mortality varied between northern and southern MDB regions. The length, weight and age ranges of golden perch sampled (n=873) were 52–559mm, 2–3201g and 0+ to 26+ years respectively, and maximum length and weight were unaffected by latitude. Length and age–length distributions represented by age–length keys varied by region, with greater variability in age-at-length and a larger proportion of smaller individuals in northern MDB rivers, which generally exhibit greater variability in discharge. Growth and mortality rates were similar between regions, and an MDB-wide von Bertalanffy growth model (L∞=447, k=0.32 and t0=–0.51) and instantaneous mortality rate (Z=0.20) best described the data. An MDB-wide length–weight equation also provided the best fit (W=6.76×10–6 L3.12). Our data suggest that the MDB can be treated as one management unit in terms of golden perch maximum size, growth and mortality parameters.

The Australian bass, M. novemaculeata, and the golden perch, M. ambigua, differed in the osmoregulatory response of the gills to salinity change. Bass displayed lower gill Na+/K+-transporting ATPase and succinate dehydrogenase activities in salt water than in fresh water, whereas golden perch displayed the opposite pattern. This difference may indicate that the golden perch has evolved further toward a fresh- water life cycle than the bass, with reduced osmoregulatory effort, particularly in the critical juvenile phase, in fresh water. The spawning and initial juvenile residence of bass in hypertonic conditions may similarly represent preference for, or adaptation to, a habitat that requires reduced osmoregulatory effort by the juveniles. It is suggested that artificial rearing conditions known to compromise the development of Na+/K+-transporting ATPase-dependent osmoregulation in other species should be avoided, particularly in bass reared in high salinities for stocking into fresh water.

Golden perch (Macquaria ambigua) larvae were studied in a pond and an adjoining inundated floodplain to determine the influence of water quality and prey density on larval dispersion. Mean catches in both pump and light-trap samplers were greatest at midnight (4.08 and 11.58 larvae per sample, respectively), with relatively few larvae caught at dawn, midday and dusk. A total of 1421 larvae were collected in 320 samples from the pond (4.4 larvae per sample), whereas only 354 larvae were caught in 480 samples (0.7 larvae per sample) from the floodplain. Neither total plankton density nor the density of specific size classes of plankton were correlated with the distribution of golden perch larvae. Dissolved-oxygen concentrations were higher in the pond than on the floodplain and were significantly correlated with the spatial distribution of golden perch larvae. Tannin and lignin concentrations were also greatest on the floodplain. These results suggest that water quality may exert a greater influence than does food availability on the distribution of native fish larvae in artificially inundated floodplain habitats.

Karyotypic data from Australian native freshwater fishes are scarce, having been described from relatively few species. Golden perch (Macquaria ambigua) and Murray cod (Maccullochella peelii) are two large-bodied freshwater fish species native to Australia with significant indigenous, cultural, recreational and commercial value. The arid landscape over much of these fishes’ range, coupled with the boom and bust hydrology of their habitat, means that these species have potential to provide useful evolutionary insights, such as karyotypes and sex chromosome evolution in vertebrates. Here we applied standard and molecular cytogenetic techniques to characterise karyotypes for golden perch and Murray cod. Both species have a diploid chromosome number 2n = 48 and a male heterogametic sex chromosome system (XX/XY). While the karyotype of golden perch is composed exclusively of acrocentric chromosomes, the karyotype of Murray cod consists of two submetacentric and 46 subtelocentric/acrocentric chromosomes. We have identified variable accumulation of repetitive sequences (AAT)10 and (CGG)10 along with diverse methylation patterns, especially on the sex chromosomes in both species. Our study provides a baseline for future cytogenetic analyses of other Australian freshwater fishes, especially species from the family Percichthyidae, to better understand their genome and sex chromosome evolution.

Populations of golden perch (Macquaria ambigua) were sampled from both sides of the Great Dividing Range (GDR): from the Murray-Darling drainage basin (Murray R., L. Keepit and Condamine R.), the L. Eyre internal drainage basin (Barcoo R. and Diamantina R.), and the internal drainage basin of the Bulloo R.-all to the west of the GDR-and from the Fitzroy drainage basin (Dawson R. and Nogoa R.) east of the GDR. Starch-gel and polyacrylamide electrophoresis of 12 enzyme systems plus two general muscle proteins was used to estimate the genetic variation within and between populations. Of the 18 presumed genetic loci examined, nine were either polymorphic at the P0.99 criterion level or exhibited fixed allelic differences between some of the populations. Within the Murray-Darling drainage basin, there was little indication of heterogeneity. Contingency Χ2 analyses of allelic distributions among drainage basins indicated significant levels of heterogeneity at six variable loci. The isolated L. Eyre population exhibited diagnostic alleles at four loci when compared with the Murray- Darling and Fitzroy populations. The genetic distance of the L. Eyre population (Nei's D=0.23) from these two populations indicates that the L. Eyre golden perch is most probably a previously unrecognized allopatric species. The level of divergence (0 = 0.06) between Fitzroy and Murray-Darling golden perch indicates differentiation at the subspecies level, with no fixed differences observed between these two populations. Finally, golden perch from the Bulloo R. represent either (i) an intermediate evolutionary unit between the presumed ancestral L. Eyre population and the derived Murray-Darling and Fitzroy populations or (ii) a complex hybrid between these populations. Average gene-flow statistics, FST = 0.760 and Nem=0.08, suggest that the populations in each of the four basins can be regarded as separate gene pools that have been isolated for different, and considerable, periods of time.

Dams and weirs are widely implicated in large-scale declines in both the range and abundance of aquatic fauna. Although many factors are involved, such declines are commonly attributed to the prevention or reduction of migration, reductions in available habitat, alteration of natural flow regimes and changes to physicochemical characteristics. In Australia, studies into the ecological effects of these impacts are limited, and have concentrated mainly on species of recreational and commercial importance. Subsequently, the adverse effects of dams and weirs, and suitable methods of mitigation, remain largely unknown for many other taxa. Therefore, the major aim of this thesis is to investigate the ecological effects of dam and weir construction on previously unstudied migratory assemblages of fish and macroinvertebrates in the Murray-Darling Basin. It is anticipated that the results of these studies will feed back into improved management strategies that help arrest the previously observed declines of aquatic fauna. Initially, fish communities were sampled, by boat electrofishing, from both reference sites and downstream of Balranald and Redbank weirs on the lower reaches of the Murrumbidgee River, Australia. Sampling was stratified over large spatial and temporal scales to gain a comprehensive understanding of species most affected by the presence of these two barriers. In general, the weirs obstructed fish migrations during summer and autumn and many species of small-bodied fish such as Australian smelt, western carp gudgeon, fly-specked hardyhead and crimson-spotted rainbowfish accumulated downstream of Balranald Weir. In addition, downstream accumulations of juveniles of larger-bodied species such as bony herring, common carp and goldfish were also detected. Although many previous studies had either documented or hypothesised that upstream migrating fish accumulate downstream of migration barriers, none attempted to quantify the size of such populations. Therefore, a simple but efficient method to estimate the size of migratory populations was assessed at the Balranald Weir site. The application of two commonly used estimation techniques yielded relatively reliable results for seven species that accumulated downstream of the weir. Population size estimates were greatest for most species during summer and autumn, where accumulations as high as 800 fish per day were detected. The largest calculated population size estimates, in addition to the greatest temporal variation, of any individual species was observed in bony herring. Given the simplicity of the technique and the relative accuracy of population estimates, it was concluded that these methods could easily be applied to other weirs where the size of migratory populations is of particular interest. A study investigating the effects of Yanco Weir on the diets of three migratory percichthyid species, Murray cod, trout cod and golden perch was also conducted. Observed spatial variation in a number of trophic processes strongly implicated Yanco Weir as a major contributor to increased competition among percichthyid species on the Murrumbidgee River. The greater relative abundance of percichthyids from downstream samples, combined with increases in dietary overlap and a greater percentage of empty stomachs, also suggested percichthyids may be significantly affecting the relative abundance of potential prey items such as freshwater prawns and Australian smelt. These significant changes in dietary composition were likely related to migratory behaviour, as these species accumulated downstream of the weir, and could be readily expected at other sites where passage is obstructed. It was suggested that the construction of suitable fish passage facilities would effectively reduce the probability of migratory fish accumulating and, subsequently, potential effects of dams and weirs on trophic processes. Since it was established that dams and weirs of the Murrumbidgee River were significantly affecting migratory fish communities, an innovative but relatively inexpensive fishway design, the Deelder fish lock (after Deelder, 1958), was constructed and assessed for wider application throughout the Murray-Darling Basin. The Deelder lock was effective at mitigating the effects of Balranald Weir by providing passage for a wide range of size classes and species of fish; but importantly, the structure enabled the passage of most species previously observed to accumulate downstream of the structure. Most significant was the ability of the fish lock to pass substantial numbers of small-bodied fish, which were previously not considered migratory, suggesting that these species should be considered when developing options to mitigate the effects of other dams and weirs throughout the Murray-Darling Basin. A significant finding of this study was the realisation that substantially more species and size classes of Australian native fish are migratory than previously thought. Subsequently, it is recommended that, when designing facilities to mitigate the effects of a dam or weir, the structure of the entire migratory community is considered when developing operating parameters. Various options for mitigating the effects of dams and weirs are discussed, but it was concluded that the construction of effective fishways would be the most appropriate means of restoring migration pathways to Australian native fish. A strategic approach for assessing and adaptively mitigating the effects of dams and weirs is presented and discussed.

Inland archaeological sites in the Australian arid zone contain few records of past environments. For those archives that do exist, such as sedimentary records, it can be difficult to associate the environmental conditions that they record directly with the time scales of human occupation. At the world heritage site of Lake Mungo, in north western New South Wales, lake shore dunes preserve a record of human occupation, and of alternating phases of wet and dry conditions in the adjacent lake. These two records provide a promising opportunity to generate commensurate behavioural and palaeoenvironmental information. As further surveying of the lunettes is completed and a more detailed and robust chronology using direct Optically Stimulated Luminescence (OSL) dating of the lunettes is constructed, a fuller more nuanced picture of changes in lake level, human occupation and climate will emerge. By finding new samples, new materials and new methods of analysis the chronology of human occupation and lake level changes at Lake Mungo and other Quaternary sites will become more detailed. This study investigates the potential of golden perch otoliths, which are found throughout the shoreline dunes of Lake Mungo, for providing additional detail about lake level fluctuations and general environmental conditions. Fish otoliths are bone-like structures that form in the inner ears of bony fish. They develop by the incremental deposition of calcium carbonate onto an organic matrix, forming annual growth rings. As otolith grow they take up and preserve a record of the trace element and isotopic composition of the ambient water. Some of these chemical markers are affected by changes in water level and temperature. This study analyses the δ18OCaCO3 values and trace element (Sr/Ca and Ba/Ca ratios) composition across the age increments of golden perch otoliths. The δ18OCaCO3 values of modern golden perch from tanks of known δ18OH2O values and temperature conditions were used to validate the assumption that golden perch otoliths form in isotopic equilibrium with the ambient water. Further analyses of modern otoliths from river populations of golden perch and from populations who died in an evaporating lake were examined to determine if known flooding and drying events were preserved in their microchemistry. The same analytical methods were applied to a collection of ancient otoliths excavated from the shorelines of Lake Mungo in the 1970s to investigate changes in water conditions (flooding and drying events) through time. These ancient otoliths were also radiocarbon dated to establish a more detailed chronology of the site. This study also investigates how mass balance models and ancient otolith δ18OCaCO3 values can be used to test scenarios of lake level change at Lake Mungo.

Golden perch (Macquaria ambigua) is a valuable freshwater fish native to south eastern Australia. The fishery for this species is diminishing and there exists an opportunity to develop aquaculture techniques for commercial production. Mass production techniques for fingerlings have been developed, but the paradigm that weaning of golden perch onto artificial foods essential for aquaculture development was difficult or impossible, impeded investigations into optimising aquaculture techniques for the species. The aims of this study were to develop aquaculture techniques for golden perch, focussing on three major issues: (1) weaning fingerlings on to artificial foods; (2) the nursery phase of production; and (3) growout of the fish to market size. Additional investigation of a destructive epizootic in aquaculture golden perch was also undertaken to develop control techniques for mixed motile aeromonad/ciliate protozoan infections. Weaning of fingerling golden perch was investigated after discussions with industry indicated that reliable, cheap, mass production of fingerlings was regularly undertaken and there was no real need to wean larvae or fry. Fingerlings used in weaning experiments (18-31 mm TL, 0.1-0.5 g) are produced by commercial hatcheries for recreational fishery enhancement. A weaning technique using frozen Artemia nauplii and formulated crumble food ice blocks was developed, in which the frozen Artemia was gradually replaced by crumble food particles. Artemia nauplii slurry was replaced with crumble food particles, with the proportion of crumble increasing by ten percent each day until 100% crumble food was being fed to the fingerlings after ten days. Iceblocks of pure Artemia slurry, presented in a mesh bag, were fed over an acclimation period to habituate fish. Subsequently prepared co-feeding (Artemia/crumble) iceblocks were fed using the same method. This method was successful resulting in 77% weaning success. Due to the relatively high cost of Artemia, frozen zooplankton was tested as an alternative and produced better weaning results than the control Artemia weaning treatment in terms of survival (16% better) and growth (1.57 g ± 0.55 g on zooplankton against 1.11 ± 1.07 g on Artemia). This was adopted as the control treatment and the method of choice for mass weaning of fingerlings for nursery and growout trials. After requests from industry for alternatives to plankton or Artemia in weaning fingerlings, commercially available seafood products were tested as cofeeding diets in the weaning process. Squid, fish roe, prawn, mussel, scallop, and fish were tested against a zooplankton control. The seafood materials were processed to be a similar size to the plankton control (500 μm – 1.5 mm) and co-fed with crumble as iceblocks in 10% increasing increments and compared to a zooplankton control. Weaning using zooplankton as a co-feeding diet was far superior to other treatments tested in terms of both survival and growth. The best survival rates of the seafood treatments (the fish roe co-feeding treatment) was 39% and the poorest survival rate of zooplankton co-fed controls was 87% in the first trial. End weights of golden perch on all weaning treatments were significantly different (P<0.05) to the control. The olfactory and organoleptic properties of the co-feeding weaning diets were suggested to be of great importance in success of weaning. Weaning techniques were further refined by investigating the effect of the duration of the transition period, the size of fingerlings, and light intensity on weaning success in fingerling golden perch. Attempts to reduce the co-feeding period or alter the ten-day transition period reduced weaning success significantly, from 62% feeding fish in the control treatment to between 36 and 46% for abbreviated treatments, suggesting that a minimum ten day transition period was essential for golden perch fingerlings. Mean weights at the end of the trial were also significantly different (P<0.05) (2.1 ± 0.97 g for controls, and 1.6 ± 0.83 g to 1.8 ± 0.99 g for treatments). The effect of size of fingerlings at weaning was tested (using fingerlings of the same age but different sizes), and no significant differences in weaning success were found between sizes from 0.1–0.24 g, suggesting that early weaning may provide significant benefits through a rapid transition to artificial diets. The effect of light intensity on weaning of golden perch fingerlings was tested, with bright light, low light level and no light treatments. Golden perch weaned best in low light (1.79±0.081 lux) and bright light (73.64±0.55 lux), but over 6% of those in the dark treatment (0.00965± 0.00275 lux) were weaned successfully. The low light treatment produced significantly better results in terms of condition (3.45 ± 0.01 compared to the bright treatment (2.9 ± 0.01) (P<0.05), but was not significantly different in terms of survival or growth. Two experiments were conducted on weaned golden perch to determine effects of density and diet on growth of golden perch in tanks. Firstly, in order to test the effect of density on growth of fingerlings, and to determine if density used in the weaning trials was suitable, golden perch fingerlings were grown in tanks at densities of 1000, 2000, 7500 and 10000/m3 for 82 days. At high stocking density there was less heterogeneity in growth than at low density, but overall growth was slower. Fish in the highest density treatment weighed significantly less (5.9 ± 0.3 g) than other groups (7.1± 0.3 g to 7.9 ± 0.4 g). Secondly, due to perceptions in industry that pellet texture was an impediment to golden perch feeding, a soft pellet was prepared using gelatine as a binding and moistening agent, and tested against the three commercially available dry pelleted feeds. Growth of golden perch fed on moist pellets (2.44 ± 0.07 g to 2.6 ± 0.07 g) was significantly less than that of fish fed dry pellets (3.4 ± 0.09 g and 3.83± 0.09 g). After the issues in weaning golden perch on to artificial foods were resolved, trials to assess growth rates of golden perch in pond culture conditions were undertaken. The initial trial was conducted at two densities (105, 000 and 31, 250 fish/ha) for 220 days, with two replicates for each treatment. There were differences between the treatments in terms of growth (low densities 96.86 ± 9.62 g and 121.92 ± 10.61 g; and high densities 83.75 ± 10.01 g and 89.02 ± 10.65 g), but only the heaviest high density treatment was significantly different to the others. The size frequency distribution of high density treatment was skewed to the left (i.e. a high proportion of small fish) and bimodal, whereas in low density treatments it was more normal. To determine the reason for the skewed distribution the density experiment was repeated with greater replication (3 replicates of each treatment) and fish were sampled regularly to determine the role of diet in growth patterns. The results showed that a large proportion (67-70%) of fish reverted back to eating natural foods and that these were generally much smaller (mean weight about 10g) than those which retained pellet eating behaviour (mean weight around 80g). For every percentage point of pellet in the gut the weight was on average increased by 0.6423%. Analysis of natural diets determined that golden perch are more selective feeders than previously thought with smaller fish selecting Moina as prey over copepods, and larger fish feeding on chironomids or Trichoptera but not on Ephemeroptera or Odonata. In order to test whether exposure to formulated food had a major influence on retention of weaned golden perch on pellets, a further experiment was run to test the effect of broadcast feeding. The results indicated that broadcast feeding significantly enhanced retention of fingerlings on pellets (42.5% retention in broadcast fed treatments against 25% in point feed treatments) and overall growth rates were therefore improved. Broadcast fed fish (15.639 ± 1.07 g) were significantly larger than point fed fish (10.74 ± 0.52 g and 10.899± 1.14 g) at the end of a four month nursery period. In addition, a commercial probiotic product was concurrently tria[l]ed to determine whether probiotics had positive effects on water quality or health of fish. The results were too variable to permit meaningful analysis, due to the inherent variability of pond based production systems. Growout of golden perch to market size after nursery phase was also conducted. To determine whether the smallest golden perch did have growth potential in a commercial setting, the entire contents of six ponds of fish were graded after nursery phase into the smallest 50% and the remainder. The different groups were then restocked into separate ponds. Ungraded controls (at the original density of 1265 fish/pond, approximately 4 fish /m2) were maintained as a control group. Sex ratios of the respective populations suggested that there was selective mortality of the fastest growing females due to grading (70% males in graded treatments compared to 62% males in the ungraded treatments). The majority of the small size class of fish did not reach market size in the six months after grading. Small fish started at 6.2 ± 0.4 g finished at mean weight of 107.6 ± 10.83 g, compared to large fish stocked at 15.7 ± 0.2 g which grew to a mean weight of 235.1 ± 20.56 g. Ungraded fish averaged 10.9 ± 1.14 g at the start of the experiment and averaged 165.7 ± 22.43 g at the end. Small fish did not appear to grow rapidly when separated from potentially dominant, larger fish, suggesting that factors other than behaviour influenced the size frequency distribution of golden perch cultured in ponds Finally, when a mixed motile Aeromonad and hymenostome ciliate infection destroyed fish in early growout trials during this study, the aetiology and pathology of the disease was documented and an effective treatment devised. It was determined that Tetrahymena corlissii is a primary pathogen to naïve golden perch, and that motile aeromonad bacteria were probably secondary invaders. An effective treatment using a systemic protozooicide was administered which halted mortalities. Previously, Tetrahymena had not been reported in Australia, or in food fish, as a primary pathogen of fish in well managed ponds. In summary, the results of this study indicate that golden perch can be weaned on to artificial foods and do have potential for aquaculture, although there are still issues regarding feeds and feeding (particularly retention of artificial foods), and handling of fish (and subsequent losses due to infections), which require further research for the industry to develop rapidly. However, their potential rapid growth, high market price, and tolerance of poor water quality engender them to profitable aquaculture production systems.

Australian freshwater systems have highly variable flow regimes influenced by El Nino dry- and La Nina wet- phases of the Southern Oscillation climate phenomenon (SOI). A system characterised by strong climate forcing offers opportunities to disentangle the links between fish growth and climate in order to determine how fish populations could respond to changes in flow arising from climate change or anthropogenic activities (water extraction, river regulation, etc). Life histories (an organism's schedules of growth, maturity and longevity) form the very essence of population dynamics and thus are likely to comprise a sensitive suite of characteristics for reflecting differences in the environment and climates that populations have experienced. An ideal way to investigate life-history variation is through the use of otoliths to extract age information and reconstruct growth chronologies. This thesis is novel in that otolith growth chronologies extracted from an extant fish species were firstly validated as environmental recorders of climate over a range of spatial scales (from single reservoir to river system), and then modem life-histories were compared with Pleistocene remains of the same species over truly evolutionary timescales. This PhD studied the otoliths of the Australian freshwater fish golden perch, Macquaria ambigua (Percichthyidae). Golden perch are common and widespread across fifteen degrees of latitude and occur in four major drainage basins across southeastern and central Australia. Given their broad distribution, extant populations currently experience a wide range of climatic regimes and large differences in age and growth were expected. This study firstly established that golden perch otoliths were suitable for reconstructing growth chronologies by validating the three central assumptions that otoliths could be aged accurately, measured precisely and that otolith growth sensitively reflected relative somatic growth. During this validation, a Biochronology macro was developed to improve the precision of otolith annual-growth measurements by ensuring their orthogonality to the direction of otolith growth even with changing annual opaque zone orientations across the otolith section. This Biochronology macro was then applied to golden perch collected from Googong reservoir, New South Wales, which is at the upper altitudinal and lower thermal limit of the biogeographical range for golden perch. Otoliths proved to be excellent archives of the local environmental conditions experienced over 1982 to 1999 as synchronous interannual growth fluctuations were recorded in the somatic and otolith increment width records for fish of all ages. 73 .4% of the inter-annual variation in the population growth chronology was explained by three environmental parameters: fluctuations in Googong reservoir's water level, minimum dissolved oxygen saturations, and the length of the growing season (number of degree days exceeding 20°C). Low water levels, low oxygen saturations and short growing seasons all combined to result in poor fish growth. These linkages between fish growth and local environmental conditions from a single reservoir were then scaled up to determine if there were synchronous fluctuations between widely separated populations in years of strong climate forcing. 1,240 golden perch otoliths were measured from seven populations that were isolated from one another by barriers to dispersal (dams and weirs). Five populations were clustered around the Australian Capital Territory and two populations were located hundreds of river kilometres downstream in New South Wales. The twenty-nine year growth chronology from 1972 to 2000 was highly correlated with the average annual values of the Southern Oscillation Index (SOI) over 1972-1992 but not over the final eight years 1993-2000 (correlations of 0.59 and -0.62 respectively). This highlights that rather than there being a predictable relationship between fish growth and the SOI through time, populations can drift in and out of synchrony dependent upon the relative combination, strength and autocorrelation of sub-components of high frequency climate disturbances. Growth chronologies were then constructed at the opposite climate extreme to the southern Murray-Darling Basin (MDB), focusing on golden perch inhabiting the intermittent rivers of the Lake Eyre Basin (LEB) that run through the deserts of Central Australia. However, similar to the results for golden perch growth in the cooler and less arid MDB, otolith chronologies in the LEB were highly synchronous among individuals and were significantly correlated with annual discharge. Annual discharge explained 74% and 18% of the inter-annual growth variation for fish from the Diamantina River and Cooper Creek respectively. Finally, the age and growth of golden perch at the two extremes of their extant range (MDB and LEB) were compared with Pleistocene remains of the same species 20- 17,000 years ago (calendar years). This was in order to estimate life-history divergence across modem populations as well as investigate the extent of change over thousands of years. The Pleistocene otoliths were from the dry Willandra Lakes in the MDB, dated back to an oscillatory lake phase shortly after the last glacial maximum (6-9°C cooler than modem). Although there have been no changes to external otolith dimensions, substantial age differences were described for fossil and modem samples. In particular, older age classes were far more common for Pleistocene golden perch (up to 43 years) when compared to their modem counterparts (up to 26 years). Otolith increment widths at age were also narrower, interpreted as representing slower somatic growth during the glacial climate phase. The slower growing and greater longevity Pleistocene golden perch could well have reached larger asymptotic sizes than historical records (23kg and 76cm) given the well known demographic trade-offs among these traits. For comparisons among modem populations, age distributions were similar for LEB and MDB populations, even though the lower mortality MDB environments were expected to have a greater frequency of older age classes. It is suggested that a lack of older age classes in the MDB may represent a legacy of commercial over-exploitation during the 19th and 20th Centuries as well as a disruption of ecological processes through river regulation. Comparisons of otolith growth patterns revealed that the LEB population had wider increment widths-at-age when compared to the MDB, most likely as a function of longer growing seasons, warmer temperatures and faster growth. Spatial divergence of modem life-histories were identified, but the magnitude of differences across modem climate extremes were nowhere near as substantial as the growth and longevity changes over the last 20,000 years of climate change. In conclusion, otoliths offer considerable potential as growth archives to retrieve the environmental histories of both individuals and populations over a wide range of spatial and temporal scales.

<em>Abstract.—</em>The brook trout <em>Salvelinus fontinalis </em>is endemic to the eastern United States, and historically was abundant in the lakes and ponds of the Adirondack Mountain region of New York State. Anthropogenic impacts have caused drastic declines in brook trout populations. A major cause of the decline has been introduction of competing fishes such as nonnative yellow perch <em>Perca flavescens</em>, bass <em>Micropterus spp</em>. and golden shiners <em>Notemigonus crysoleucas</em>. Range expansion of native fish species such as white suckers <em>Catostomus commersoni </em>and brown bullheads <em>Ameiurus nebulosus </em>has also been detrimental. Brook trout, a species that was commonly found alone or in simple communities with only one or two other fish species, is unable to compete successfully in these situations. Chemical reclamation using rotenone is the only viable tool that can restore these degraded systems. Follow-up studies by New York State biologists and Cornell University researchers have supported the findings of others; that the negative impacts of pond reclamation with rotenone are minor and short-term.

<i>Abstract</i>.—Recent studies have described nonlethally detectable techniques for externally marking fish with fluorescent compounds such as calcein. We describe the use of a portable fluorometer for the nonlethal quantitative measurement of fluorescence in calcein marked golden perch <i>Macquaria ambigua</i>. The results demonstrate that calcein marked fish could be unambiguously identified more than 2 years after marking when held in the laboratory; the body mass of the fish had increased from 0.8 to 1.3 g (median 1.0 g) to 6–44 g (median 11.1 g) over this period. Similarly, marked fish released into the wild at approximately 1 g were detected at up to 18 months postrelease and 66 g in weight. However, some deterioration in the detectability of the external marks was apparent in the larger fish recaptured from the wild. Based on these findings, we suggest that the technique has the potential to provide a practical and objective means of discriminating hatchery and wild fish under field conditions.

<em>Abstract</em>.—The Murray-Darling basin produces about 40% of the total value of Australia’s agricultural output from 1.9 million ha of irrigated agriculture that represents around 75% of the nation’s total irrigation. Major reservoirs in the southeastern states regulate the basin’s river systems for irrigation but also provide recreational fisheries. One of these storages is Lake Eppalock in the state of Victoria, a multi-use impoundment built in 1964 covering 3,230 ha and holding 312,000 ML at full supply level. It has been actively developed as a mixed species recreational fishery (golden perch <em>Macquaria ambigua </em>and Murray cod <em>Maccullochella peeli</em>) and is a popular angling water. The principal recreational target species in the lake compete with invasive pest species (common carp [also known as European carp] <em>Cyprinus carpio</em>). Drought is part of the natural variability of the Australian climate and its rainfall history features several periods of a decade or longer that have been distinctly drought-prone. Eastern Australia was in the eighth year of the latest drought cycle in 2007, and Lake Eppalock had fallen to less than 1% of its full supply level. These conditions highlighted increasing competition for water and brought into focus the interdependence and linkages between fisheries management and water needs, both for irrigation and for the environment. Fisheries managers faced a very strong likelihood of extensive fish deaths in the lake and elsewhere that could cause significant long-term impacts requiring many years to recover the recreational fishery. A planned partnership approach with the storage water authority was adopted in 2006 for integrated fisheries and water management, with response actions targeted to achieve storage conditions ensuring the maximum survivability of key recreational angling species in the lake through the drought. The framework for cooperation established in this study provides an example for future water allocation disputes.

Abstract The Kalgoorlie gold camp in the Yilgarn craton of Western Australia comprises the supergiant Golden Mile and the smaller Mt. Charlotte, Mt. Percy, and Hidden Secret deposits. Since the camp’s discovery in 1893, ~1,950 metric tons (t) of Au have been produced from a total estimated endowment of ~2,300 t. The camp is located within Neoarchean rocks of the Kalgoorlie terrane, within the Eastern Goldfields superterrane of the eastern Yilgarn craton. Gold mineralization is distributed along an 8- × 2-km, NNW-trending corridor, which corresponds to the Boulder Lefroy-Golden Mile fault system. The host stratigraphic sequence, dated at ca. 2710 to 2660 Ma, comprises lower ultramafic and mafic lava flow rocks, and upper felsic to intermediate volcaniclastic, epiclastic, and lava flow rocks intruded by highly differentiated dolerite sills such as the ca. 2685 Ma Golden Mile Dolerite. Multiple sets of NNW-trending, steeply dipping porphyry dikes intruded this sequence from ca. 2675 to 2640 Ma. From ca. 2685 to 2640 Ma, rocks of the Kalgoorlie gold camp were subjected to multiple deformation increments and metamorphism. Early D1 deformation from ca. 2685 to 2675 Ma generated the Golden Mile fault and F1 folds. Prolonged sinistral transpression from ca. 2675 to 2655 Ma produced overprinting, NNW-trending sets of D2-D3 folds and faults. The last deformation stage (D4; &lt; ca. 2650 Ma) is recorded by N- to NNE-trending, dextral faults which offset earlier structures. The main mineralization type in the Golden Mile comprises Fimiston lodes: steeply dipping, WNW- to NNW-striking, gold- and telluride-bearing carbonate-quartz veins with banded, colloform, and crustiform textures surrounded by sericite-carbonate-quartz-pyrite-telluride alteration zones. These lodes were emplaced during the earlier stages of regional sinistral transpression (D2) as Riedel shear-type structures. During a later stage of regional sinistral transpression (D3), exceptionally high grade Oroya-type mineralization developed as shallowly plunging ore shoots with “Green Leader” quartz-sericite-carbonate-pyrite-telluride alteration typified by vanadium-bearing muscovite. In the Hidden Secret orebody, ~3 km north-northwest of the Golden Mile, lode mineralization is a silver-rich variety characterized by increased abundance of hessite and petzite and decreased abundance of calaverite. At the adjacent Mt. Charlotte deposit, the gold-, silver-, and telluride-bearing lodes become subordinate to the Mt. Charlotte-type stockwork veins. The stockwork veins occur as planar, 2- to 50-cm thick, auriferous quartz-carbonate-sulfide veins that define steeply NW- to SE-dipping and shallowly N-dipping sets broadly coeval with D4 deformation. Despite extensive research, there is no consensus on critical features of ore formation in the camp. Models suggest either (1) distinct periods of mineralization over a protracted, ca. 2.68 to 2.64 Ga orogenic history; or (2) broadly synchronous formation of the different types of mineralization at ca. 2.64 Ga. The nature of fluids, metal sources, and mineralizing processes remain debated, with both metamorphic and magmatic models proposed. There is strong evidence for multiple gold mineralization events over the course of the ca. 2.68 to 2.64 orogenic window, differing in genesis and contributions from either magmatic or metamorphic ore-forming processes. However, reconciling these models with field relationships and available geochemical and geochronological constraints remains difficult and is the subject of ongoing research.

Genus Prunus includes all the stone fruits (peach, nectarine, plum, apricot, almond and cherry) comprise around 98 species and classified under three subgenera namely: Amygdalus (peaches, nectraine and almonds), Prunophora (plums and apricots) and Cerasus (cherries). Genus Prunus have attained a prime position among all the temperate fruit crops as delicious edible drupe, and many species have ornamental values as well. Major species of importance are Prunus persica (peach), Prunus armeniaca (apricot), Prunus salicina (Japanese plum), Prunus domestica (European plum), Prunus americana (American plum), Prunus avium (Sweet cherry), Prunus cerasus (Sour cherry), Prunus dulcis (almond), Prunus ceracifera (Cherry plum), Prunus mira (Behmi), Prunus cerasoides (Wild Himalayan cherry), Prunus mahaleb (Mahaleb cherry) etc. Interspecific hybrids namely: plumcots, pluots and apriums also produce very delicious edible fruits. Commercial cultivars of different stone fruits are J H Hale, Cresthaven, Flordasun, Florda Prince, Elberta, Glohaven, July Elberta, Redhaven, Kanto 5, Sun Haven etc. of peaches, Fantasia, Mayfire, Red Gold, Snow Queen etc. belongs to nectarine, Turkey, Charmagz, Perfection, St. Ambroise, Royal, New Castle etc. are apricots, Santa Rosa, Black Beauty, Kelsey, Green Gage, Methley, Satsuma, Frontier, Burbank etc. are plums, Regina, Burlat, Lapins, Kordia, Stella, Bing, Van, Black Heart, Compact Lambert, Compact Stella etc. are cherries, and California Paper Shell, IXL, Mission, Nonpareil, Drake, Ne Plus Ultra, Pranyaj, Merced etc. are almonds.

This chapter considers the generic and material conventions of writings by Egyptologists alongside those of fiction, observing a multifaceted intertextual relationship between these forms. I outline how book designs incorporating gilt mimicked Egyptian artefacts, capitalising upon the sensationalism with which discoveries of gold relics were reported whereby these objects were coded as ‘treasure’. Further to the physical parallels between Egyptological writing and fiction, this chapter charts mutual textual influences. With particular focus on the first two volumes of The Tomb of Tut·ankh·Amen (1923; 1928), it compares the published version of accounts of discovery to Howard Carter’s original notes recorded at the time of the excavations, shedding light on a revised and romanticised narrative, and paying attention to both the atmospheric effects of Harry Burton’s photographs as well as the tangible influence of the novelist Percy White. Considering, too, the account of the death of Carter’s canary published in Pearson’s Magazine as ‘The Tomb of the Bird’, it discusses Carter’s conflicted relationship with the notion of the pharaoh’s curse, proposed by some as being behind the death of Carter’s patron, the fifth Earl of Carnarvon – by this time a familiar trope of Gothic fiction.