Antarctic krill use a variety of strategies to cope with, and thrive in the highly variable Southern Ocean environment. Despite much detailed information on its basic biology produced so far, the linkages between krill populations and the environment are yet to be systematically investigated. There is a practical need to have standardised indicators to assess the 'condition' of krill in relation to seasonal cycles and shifts in physical regimes and this study has aimed to develop such indicators. The level of nucleic acids in abdominal tissue was determined as an estimator of growth rates of individual krill that could otherwise only be obtained by on-board experiments. The dynamics of the major digestive organ, the digestive gland, in its size, protein and lipid content and enzyme activities, were examined in relation to changing food regimes. The potential of using eye diameter as a long-term starvation indicator was also examined. The amount of RNA and RNA:DNA ratio in krill muscle exhibited a significant relationship with individual growth rates, although the predictability was only modest. This was the case with both field-caught specimens and experimental juveniles. RNA-based indices were clearly different between well-fed, high-growth krill and underfed low-growth krill, and the RNA content levelled off when the growth rates became negative. The moult cycle had no significant effect on nucleic acid content. Overall, the content of nucleic acids varied considerably between individuals. Starved krill also tended to have higher DNA per unit biomass, which implies shrinkage of cells rather than loss of cells. The experimental krill showed a rapid response to the food conditions in their growth rates, either in a positive or negative direction, well within a single moult cycle. The digestive enzyme activities in the digestive gland of field-caught adults decreased considerably during one week of starvation. The size of the gland decreased substantially both in length and weight, accompanied by a loss of lipid and protein, with the former being more readily utilised. In a laboratory experiment where juvenile krill were alternately fed and starved, the digestive enzyme activities changed in response to the food regime. These changes largely mirrored the mass gain and loss of the digestive glands. The gland size-specific activities of digestive enzymes showed no consistent trends even after a long period of starvation. When the food supply was resumed, the gland regained its mass and enzyme activities. The digestive gland appears to serve as a reserve, which can provide against a few days' starvation and be rebuilt relatively quickly. Its size showed a prompt and steady response to short-term changes in feeding regime, proving a reliable indicator of recent feeding activities. By tracking individuals over time and examining specimens sampled as groups, it was demonstrated that fed and starved krill are distinguishable by the relationship between the eye diameter and body length. The eye diameter of starved krill did not decrease even when the animals were shrinking in overall body length. The eye digmeter of well-fed krill continued to increase as overall length increased. This created a distinction between fed and starved krill while no simultaneous separation was detected in terms of the body length to weight relationship. It would take approximately 2 moult cycles of shrinkage or more at modest rates for the eye diameter to body length relationship to significantly change. Whether this feature is manifested in the wild would be best seen at the end of winter, after the most likely period of extended food limitation. Nucleic acid content has only limited predictive power as an estimator of growth rates. Growth rates measured by the 'instantaneous growth rate' technique are still the best representation of in situ growth, which is determined by the condition during the period since the last moult. The size of the digestive gland of krill, a crucial short-term storage organ, was more responsive to food condition than enzyme activities. The gland size is a result of feeding activities over the past few weeks and will not be affected by immediate past events such as cod-end feeding. The digestive gland size should, at least, be a simple measure of whether krill have recently undergone severe, sustained food shortage. Long-term, seasonal starvation and the shrinkage it caused over a few moult cycles can be seen in the body length to eye diameter relationship more obviously than the traditional body length to weight relationship. This suite of measurements will provide a matrix of methods to determine the 'condition' of krill, in time scales from a week to a few months. These techniques are now ready for repeated measurements in the field over wider temporal and spatial extent to examine their applicability and to contribute to unravelling the outstanding questions in krill biology.

Striped trumpeter, Latris lineata (Forster), are being experimentally cultured by the Tasmanian Aquaculture and Fisheries Institute (TAFI) at Taroona, Hobart, Tasmania, Australia. Fish that survive beyond 30 days develop nervous aberrations associated with a severe granulomatous meningoencephalomyelitis. The myxozoan parasite Pentacapsula neurophila was described as the parasite causing the disease in the striped trumpeter juveniles. Molecular Bayesian phylogenetic analysis using small subunit ribosomal DNA (ssu rDNA) gene sequence and the covariotide evolutionary model, has shown P. neurophila to reside firmly within the clade comprised of Kudoa species, histozoic parasites of fish from the order Multivalvulida with 4 or more shell valves containing polar capsules. This has provided molecular evidence resulting in the proposed new combination of the Kudoidae to include this Pentacapsula species. A polymerase chain reaction (PCR) diagnostic assay was developed from the ssu rDNA gene sequence to detect Kudoa neurophila (formerly known as Pentacapsula neurophila). The assay is sufficiently species specific and sensitive enough to detect a small fragment of the parasite ssu rDNA gene (0.1 spore or 60 fg DNA or 4 spores g-1 /25 microlitres PCR reaction). Specifically, the test is capable of detecting early stages of the life cycle within the fish host and consequently diagnosing an infection not normally detected using histology. The PCR test can also be used to screen water supplies and prey cultures throughout the hatchery system to determine bio-security efficacy, assist in epizootiology studies, identify infected alternative or other primary hosts indicating the location of the disease reservoir, and enable a targeted approach to disease prevention in an aquaculture situation. Histology and in situ hybridisation techniques were incorporated into the study of the histopathology of the disease caused by this parasite to elucidate its entry point on the fish host and migratory pathway to terminal stage sporulation. Kudoa neurophila enters the fish via epithelial cells as early as 25 days post hatch (dph). Parasite cells then appear within plasmodia in skeletal muscle tissue between 50-80 dph. This appears to be the first key proliferation stage which is followed by another plasmodial stage in the peripheral nerve pathways near the spinal cord (70-115 dph). It is during this stage that clinical signs of the disease, such as whirling, become apparent. The presporogonic cells then enter the spinal cord where terminal stage sporulation occurs throughout the brain and spinal cord (105-130 dph) causing acute pathology, eventually resulting in the death of the animal. The information gained from the research conducted in this thesis, along with incorporated epizootiology studies, form the foundation of understanding that has assisted the hatchery management team to make informed health management decisions with an outlook to produce healthy juvenile striped trumpeter for on-going research into the development of this species for marine sea cage aquaculture.

This thesis examines the development of sustainability indicator systems (SIS) as a tool to implement the concept of sustainability into fisheries management. This research focuses upon the identification and evolution of these systems, their application as a management tool, and their response to problems in fisheries sustainability. The thesis presents a series of ten case studies that outline differing approaches to developing SIS in marine capture fisheries. These national, regional and non government case studies provide an opportunity to strategically assess and evaluate the use of SIS in fisheries management. The United Nations Conference on Environment and Development in 1992 addressed sustainable development as a means to satisfy the needs of human societies within the constraints presented by natural systems. Over the last ten years, sustainable development has been adopted by local, regional, national, and international institutions and instruments. Implementing and operationalising the concept of sustainable development has, however, provided significant challenges. Marine capture fisheries witnessed rapid development in the second half of the 20th Century. As pressure increases on capture fisheries, it is important that measures are introduced to ensure sustainable use of such fisheries. These measures include methodologies and frameworks for the assessment and management of fisheries incorporating biological, environmental, economic and socio-political relationships - the core of sustainable development. This thesis examines the viability of sustainability indicators as a tool for assessing progress towards sustainability. Indicator systems have been implemented across a range of fisheries jurisdictions with varying degrees of success. In assessing SIS in practice, several key components were distilled from the case studies and the assessment framework. The research demonstrates that SIS are used in national environmental reporting and fisheries specific systems across a range of legal and policy contexts, can link directly to the fisheries management process, and focus at the scale of fishery operations. Target species indicators are well advanced in SIS practice, ecosystem indicators are being rapidly developed and tested, and socio-economic and governance indicators require further progress. In terms of addressing sustainability outcomes, SIS are shown to facilitate scientific and policy coordination, increase transparency, accountability and co-management, increase the participation of environmental and non-government organisations, and provide the structure to implement ecosystem based management and precautionary approaches. While some SIS have been successful in developing measurement frameworks, criteria, objectives and indicators and adapting to specific policy contexts, further progress is required in developing reporting protocols, visualisation tools and aggregation methods.

Several major reviews have recently highlighted the interest amongst life scientists in understanding the ecological and evolutionary significance of animal personality traits (e.g., Wilson 1998; Gosling 2001; Sih et al. 2004a). The term personality trait as it is used here simply refers to consistent individual differences in an animal's behavioural style (as opposed to its discrete acts), and therefore, represent a potential suite of behavioural traits that can describe behavioural individuality in animals. Using personality descriptors such as shyness-boldness, activity, etc., has the advantage in that we can describe holistic, aggregate behaviour of animals that may be important for selection between individuals. Understanding how animal personalities interact with life history strategies may help explain how individuals make-up populations, an important issue in evolutionary and population ecology. While intuitively appealing, our knowledge of how intra-population individual differences in behaviour influence life histories is in its infancy (Wilson 1998). Cephalopods are well-known for their inter-individual variation in several key life history traits (e.g. growth and age-at-maturity), represent important commercial species in a number of worldwide fisheries, and also display complex individual behaviours (Sinn et al. 2001). Through a series of four experiments this project investigated personality traits in squid and their biological and ecological consequences. Four traits (shy-bold, activity, reactivity, and bury persistence) were identified across two ecologically important contexts in wild-caught adult squid. Trait expression was sex-independent, context-specific (i.e. bold squid in threat tests were not necessarily bold in feeding ones), and was related to body size and reproductive maturity. There was high individual variability in developmental processes associated with all traits, but some of this variation was partially explained by context, age, and developmental groups of squid. A quantitative genetic study was undertaken to describe the genetic structure of traits, in order to understand the potential for traits to respond to selection as well as provide a genotypic basis to understand potential fitness-related processes. In general, there were significant patterns of additive genetic variance for threat traits but not their feed counterparts, while age-related patterns of heritability indicated age-specific genetic expression for traits in both contexts. Reproductive experiments indicated no direct relationship between a female squid's personality and her short-term fitness, but an individual's levels of feeding boldness did have consequences for its subsequent success in mate pairings. Finally, a three year field study examined the frequencies of personality phenotypes across two populations in relation to density, body size, and sex ratios of squid within each population. Observations indicated differences between years and populations in mean change and patterns of frequencies of behavioural phenotypes, but these changes appeared to be independent of patterns in population body size and sex-ratio. This study is a first attempt to relate individualized behaviour to life history variables in a cephalopod mollusc, and the results should contribute to our knowledge of how individuals make up populations, a process that is of importance to a number of life sciences, including behavioural, population, fisheries and evolutionary ecology.

A study was initiated to determine the effect of selected factors on the reproductive development and early life history of blacklip (Haliotis rubra) and greenlip (H. laevigata) abalone relevant to their wild fisheries or aquaculture. In both species, the rate of gonadal and larval development was proportional to water temperature, but the relationship was not simply multiplicative, rather there was a critical minimum water temperature below which development was arrested, known as the Biological Zero Point (BZP). The BZP for gonadal development was 7.8 degrees C for H. rubra and 6.9 degrees C for H. laevigata. Corresponding BZP values for larval development were 7.8 degrees C and 7.2 degrees C, respectively. Observations of larval development relative to temperature enabled a description of the Effective Accumulative Temperature (EAT; the cumulative difference between the culture temperature and the BZP, calculated hourly) for prominent developmental stages. The difference between the EAT for metamorphic competence and that for hatchout (i.e. the interval during which the larvae remain in the water column) was 1120 and 1160 EAT degrees C-h for blacklip and greenlip abalone, respectively. These values, in combination with water temperature data, enable the prediction of the dispersal window for each species in situ. Spawning performance of blacklip and greenlip abalone was also affected by temperature, with both sexes of each species producing significantly more gametes when conditioned at 16 degrees C than 18 degrees C. Sperm production of H. rubra was an order of magnitude greater than that of equivalent sized H. laevigata. There was no apparent difference in the lipid or fatty acid composition of the ovary or testis between pre- and post-spawning animals of either species, presumably because of partial spawning and/or incomplete resorption of the gonad. Likewise, a 4 degrees C difference in conditioning temperature (i.e. 14 degrees C vs 18 degrees C) was insufficient to elicit changes in tissue biochemistry. There was a significant interaction between sperm density and contact time on the fertilisation success of eggs from both blacklip and greenlip abalone. Prolonged exposure (> 1200 s for H. rubra and > 480 s for H. laevigata) to concentrated sperm (i.e. 107 ml-1) resulted in egg destruction. Analysis of CoVariance of F50 values (i.e. the sperm concentration required for 50% fertilisation, derived from the linear regression of logit (proportion of eggs fertilised) versus sperm density) between species across a range of contact times demonstrated that contact time had a significant effect (p < 0.001) whereas species did not (p = 0.22). The lack of a species effect suggests that the fertilisation potential of blacklip and greenlip abalone eggs are similar, at least across the range of sperm densities and contact times used.

This thesis documents research on two aspects of the biology of the giant crab Pseudocarcinus gigas: the development, behaviour, and rearing of the larvae; and the reproductive biology of both sexes. Larvae were reared from hatch to juvenile crabs. The larval development of 5 zoeal and one megalopal stages were described which permitted identification of P. gigas larvae from plankton samples. Samples from different depths were sorted to obtain information on vertical migration patterns, although few P. gigas larvae were collected. Vertical migration was further investigated in experiments which analysed the swimming response to gravity, light intensity, change in light intensity, light wavelength, change in pressure, current, temperature, and thermoclines. Response to temperature involved a feed-back mechanism that positioned larvae at temperatures optimal for growth, survival, and metamorphosis to megalopa (14-16C). Light intensity and photoperiod had little effect on survival although larvae reached megalopa most rapidly with long photoperiod and high intensity and were smaller in continuous darkness treatments. Cannibalism of stage 1 and 2 zoeas was highest with long photoperiod and low intensity. Mycosis and epibiotic fouling of larvae necessitated trials with prophylactic treatments. Survival was highest with a broad spectrum antibiotic (oxytetracyline) while promising results were obtained with carbendazim and copper oxychloride. Suitable concentrations for indefinite baths were established by monitoring toxic effects as increased mortality, deformity, prolonged intermoult, or death during moulting. The male reproductive tract is typical of brachyurans with ovoid, enveloped, spermatophores stored in the mid vas deferens (MVD). Males pass through three morphological stages (of chela development) and individuals from all three stages had spermatophores in the MVD. Mating pairs were never observed but patterns of limb loss indicate that mating involves female-centred competition. Females appear to mate while soft-shelled with stored sperm remaining viable for at least four years. Broods are produced annually although females occasionally skip a reproductive season, which may be associated with moulting. Several broods may be produced between moults although fecundity declines with successive broods. The hepatopancreas underwent little change in composition during gonadogenesis. Fecundity increased with female size, although not in a simple cubic (volumetric) relationship as larger females produced larger eggs. This increase in egg size was associated with a significant, albeit small, decrease in protein and carotenoid, and an increase in moisture, while lipid appeared unaffected. Protein was used preferentially to lipid during embryogenesis. Techniques for immobilising, humanely killing, and internal imaging of crabs were employed for research on reproduction and are described.

No description available.

Management of organic waste is a major problem for the New Zealand Mussel Industry. Currently most waste is discarded, and this represents a potential loss of both resources and revenue, unless an alternative use for this waste could be developed. Waste types were first identified, then quantified, first seasonally, then annually, to provide an estimate of total industry-wide waste production. Possible uses for this waste were then identified. Little investigative research has been undertaken on identifying alternative uses for mussel industry organic waste. The uses of organic waste as organic fertilizers, and the economic benefit of adding treated waste products to cement mix to improve its compressive strength and thermal insulation, are two primary objectives of this dissertation. The possibility of using mussel shell in agricultural liming as a substitute is also explored. The potential value of pre-grade waste as an organic fertilizer was explored by addition of decomposed tissue to tomato seedlings and by monitoring plant development and condition. Growth of treatment and control seedlings was monitored by counting the number of branches, stem heights, leaf numbers and total biomass. Analyses prove Perna canaliculus pre-grade organic waste has the potential to be exploited as an expensive, effective organic fertilizer, whereas Mytilus galloprovincialis pre-grade organic waste may not. Moreover, there is further potential to develop P. canaliculus pre-grade organic waste into an odourless, chemically stable fertilizer product. The potential value of post-grade waste in cement mixes to improve compressive strength was explored by addition of shell aggregate to cement mix. Analyses indicate that, as an aggregate, mussel shell has little to no structural potential, but does have latent thermal insulating properties. Recommendations are made to: - Separate Perna and Mytilus pre-grade waste products. - Further explore the thermal insulating potential of mussel-shell concrete. - Further explore techniques for treatment of Perna pre-grade waste as a fertilizer. - Further explore the use of crushed mussel shell as a potential limestone or sand substitute for agricultural, construction and engineering purposes. - Explore markets for Mytilus potential export, to reduce pre-grade waste production and problems of resettlement.

Doctor of Philosophy (PhD) / The management of fisheries has progressed over the past century in an attempt to solve the problem of open access. A range of controls, both economic and non-economic in nature, have been used to ration the use of marine resources. Unfortunately, many controls have failed to correct open access problems. Whilst a recent development in fishery control, protected areas defined as an area with a fishery free of extractive pressure, have been put forward as an arrangement which may, in conjunction with other controls, be used to overcome the over-exploitation of marine resources. Marine protected areas have been advocated in areas where other forms of fishery management are impractical or unsuccessful (Sumaila 1998). Arguments for protected area use are based around the heterogeneous nature of fisheries, uncertainties in marine populations and as a hedge strategy to reduce risks of over-exploitation (Conrad 1999a). Through the protection of biodiversity, improving the resilience of the ecosystem, protected areas may mitigate the effects of negative shocks (Ludwig et al. 1993 and Bostford et al. 1997). Further, protected areas have been suggested as a means to manage uncertainty and environmental stochasticity (Grafton and Kompas 2005 and Grafton et al. 2005). The protection of biomass and habitat has the potential to improve fishery returns even when stocks are not overly exploited, with the benefits accruing even from small-sized protected areas (Grafton et al. 2005). The use of marine protected areas as a management tool has resulted from a recognition that it is important to preserve biological habitats as well as stocks. From a societal point of view, the use of protected areas should be evaluated in the context of changes in resource rent and improvements in welfare. As fishery resources are often owned by a common group, usually society, management objectives should be to maximise the return from use of the resources, whether for extractive or non-extractive purposes. Given this decision criterion, protected areas can be evaluated in the sense of opportunity costs and benefits. Protected areas will influence the return from fishery resources through changes in access to fishing grounds, and thus harvest, effort and resource rent. Once a protected area is established, the flow of biomass from the protected area to the remaining fishing ground, may increase biomass, influence the effects of uncertainty and stochasticity, thus effecting mean harvests, effort and resource rent may increase. Changes in resource rent are dependent on other controls. Protected areas are a ‘blunt’ policy instrument, in the sense that they are not an instrument to capture resource rent or change the incentives of fishers. Models of marine protected areas in fisheries vary in complexity, however, a few key elements are necessary in analysing the effects of protected area creation. First, multi-species interactions have the potential to be significant in determining the outcome from a protected area; second, effort expended in the fishery must be dynamic, that is, it must be endogenously determined by the model as fishers will respond to changes in rent brought about through the establishment of a protected area; third, institutional structures that govern the expenditure of effort within a fishery will play an important role in the effectiveness of protected areas in increasing the resource rent of a fishery; and fourth, environmental stochasticity and uncertainty need to be included in the analysis. A stochastic and deterministic model of a predator-prey meta-population fishery was developed to analyse the effects of protected area creation within a fishery. Such a model has not previously been used to analyse protected area creation. The model was analytically solved to find the optimal biomass of each species in an individual patch. This allowed for a comparison of protected areas under a range of management controls ranging from those which led to open access fishing to those which led to an optimal steady-state biomass. The model allowed for linkages between sub-populations based on differing density related flows. Further, due to the linkages between species on both environmental and economic grounds, the effect of protected areas on different groups which target different species could be analysed. The benefits from protected area creation were classified into unique and non-unique benefits. Unique benefits were defined as those which solely flow from the use of a protected area as a tool in fisheries management. Two unique benefits were defined: • Improvements in the resilience of the fishery; and • Reductions in environmental stochasticity. The ability of a protected area to both improve the resilience of the fishery, and smooth fluctuations in environmental stochasticity have been shown to lead to increases in mean resource rent. Thus, protected areas were shown to form part of an optimal fisheries management structure. Generally, the resilience benefits were maximised for small-sized protected areas, whereas the reduced environmental stochasticity benefits were maximised for larger protected areas. The dispersal system between the protected area and the fishing ground affected the unique benefits from protected area creation. Sink-source dispersal increased the unique benefits from protected area creation, as stock movements occurred independently of relative population densities. The independent flow improved the ability of the protected area to hasten the return of the fishery to a steady-state and lessened the variation of harvests in the open fishing grounds. However, in the case where the protected area led to large differences in population densities, and if the area formed a sub-population that was linked to the surrounding fishing ground by density-dependent dispersal, the unique benefits are likely to be greater than under sink-source dispersal. The non-unique benefits were defined as those which could be obtained from other control mechanisms. These benefits were non-unique as they could be achieved from more stringent controls on fisher behaviour. The determinants of the non-unique benefit in terms of dispersal were the same as for the unique benefits. However, the economic conditions of the fishery determined the magnitude of the non-unique benefits. For fisheries with sub-optimal biomass, the unique benefits were greater than those with optimal steady-state biomass. The non-unique benefits identified from protected area creation were: • Changes in biomass towards optimal levels; • Changes in species biomass ratios towards optimal levels; and • Changes in effort towards optimal levels. Protected areas in fisheries may be an optimal policy choice to achieve the non-unique benefits of protected area creation. Protected areas, it has been argued, are a relatively low cost management tool, due to the lower monitoring and enforcement costs. Thus, the use of protected areas offer a solution to the problems of over extraction of fishery resources for lower transaction costs, which may erode the non-unique benefits under different policy instruments. If this is the case, then a protected area larger than is required to maximise the unique benefits of protected area creation could form part of an optimal fisheries management strategy. Whether the protected area is larger or smaller than the size that maximises both the unique and non-unique benefits of protected area creation would depend on the level of transaction costs involved in using alternative policy instruments. Protected areas were found to have distributional effects on the fishery due to changes in the species biomass ratio towards the predator species post protected area creation. The creation of a protected area will have distributional effects on the fishing industry if different fisheries target the different species separately. Fishers targeting predator species are likely to gain from the establishment of a protected area, as now the aggregate level of stocks of this species is greater, leading to both greater unique and non-unique benefits. For fisheries that target prey species, the benefits of protected area creation are lessened. The increased predation within protected area boundaries limited the unique benefits of the protected area. The low cost nature of a protected area will influence the portion of the fishery used for this type of control given an optimal policy programme. If protected areas are relatively low cost in comparison with other controls they should be used relatively more intensely. Further, the use of protected areas may hasten the evolution of fisheries away from open access exploitation towards controls which maximise the value of the fishery. With lower transaction costs, the ability to adopt protected areas over other forms of management is greater, and by doing so, the movement towards optimal exploitation will improve the discounted value of the fishery. The analysis presented in this thesis examined the benefits of protected areas to fisheries. The focus of the study was placed on the benefits to flow to a fishery if a protected area was used as a tool for wild-harvest fisheries management. Marine protected areas also have the potential to generate a range of other benefits, such as recreational values, non-use values, and potential improvements in consumer surplus from fish caught within fisheries that use protected areas. These other benefits would need to be considered when determining whether or not a protected area should be created in a fishery.

No description available.