42 resultados para THERMOCLINE WATERS

em Deakin Research Online - Australia


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The concentrations of cadmium, copper, mercury, and zinc were determined in muscle (body, claw, and leg), hepatopancreas, and gill tissues of Pseudocarcinus gigas, an exceptionally large, long-lived, and deep-dwelling crab species. The accumulation patterns observed are discussed in terms of both intra- and interspecies variations, with particular attention to the possible consequences of the extreme size and depth range of P. gigas. Metal concentrations did not depend significantly on sex of the crab. Significant differences between tissues were detected for all metals, and the distribution of metal between the tissues was different for each metal. Significant correlations were found between metal concentrations in the various tissues and crab size, and these are discussed and rationalised. The concentrations of mercury and zinc in muscle tissue increased with crab size and were high compared to other crab species. The concentrations of cadmium and copper present in edible tissues were not especially high compared to other crab species, but the concentration of cadmium in the hepatopancreas is of dietary concern.

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The mean total length (LT), mass and age of ready to migrate female silver shortfin eels Anguilla australis from the Hopkins River estuary and the mouth of the Merri River in south-eastern Australia, were 83·2 ± 1·2 cm, 1051 ± 51 g, and 17·2 ± 1·79 years, respectively. The eye index (IE) of the silver shortfin eels was < 5·2 (mean 7·64 ± 0·29) and differed significantly from that of the yellow shortfin eels collected from two other sites. The IE increased with LT (mm) and was related by log IE= 2·656 log LT6·925. The per cent moisture, protein and ash content of the liver of silver shortfin eels was significantly lower than in yellow shortfin eels, but lipid content was significantly higher in the former (35·5 ± 2·0%). The mean mass μg mg lipid ‾) of saturates (230·4 ± 2·6 v. 181·7 ±2·6), monoenes (367·4 ± 6·3 v. 290·8 ± 8·9) and PUFA (177·3 ± 5·3 v. 159·7 ± 4·6) in muscle was significantly higher, and the great majority of individual fatty acids was found also in higher quantities in silver shortfin eels. In the liver, the PUFA found in the highest quantity was 22:6n-3, except in shortfin eels from Hopkins River estuary, and the amount of 18:2n-6 in the liver of silver shortfin eels was significantly higher than that in yellow shortfin eels but the reverse was true of 20:4n-6. In both muscle and liver tissues the saturate 16:0 and the monoene 18:ln-9 collectively accounted for >50% of all the fatty acids in the lipid.

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This study was based on wild-caught blacklip abalone Haliotis rubra L., from Port Fairy waters, south eastern Australia (142°15′E; 38°21′S), from July  1998 to November 1999, and was initiated to evaluate the spawning season and other aspects of its reproductive biology. The shell length and body weight of female and male abalone sampled ranged from 12.0 to 18.6 and 12 to 15 cm, and 137 to 529 and 148 to 585 g, respectively. The sex ratio did not vary significantly from 1:1 through the year. The gonadosomatic index (GSI) ranged from 3.0% to 8.4% in males, and 2.5% to 14.1% for females, and the highest GSI as well as the highest proportion of mature animals were recorded from September to October. During these months the hepatosomatic index (HSI) was low, and an inverse correlation between GSI and HSI (P < 0.05) was evident. Fecundity of blacklip abalone ranged from 1.09 to 7.5 million eggs for females of 12–14.5 cm in length, and 115–487 g in total body weight, respectively. The lipid content of the female gonad increased significantly from about July to November, and an opposite trend was observed for lipid content of the digestive gland. Seasonal changes in the protein and ash contents of the gonad and/or the digestive gland were not always significant.

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Loxocythere (Novoloxocythere) pelius subgen. et sp. nov. is described from Upper Miocene strata of the Port Phillip and Western Port Basins. Victoria. It has its acme in shallow open marine facies of latest Miocene (Cheltenhamian) age. This species, along with Loxocythere (Novoloxocythere) kerryswansoni Yassini and Jones, 1995, forms a discrete group of rotund Australian Loxocythere species that possess posterior extremities in both valves that are positioned well above mid carapace height (i.e. adjacent to dorsal margin). This feature along with a sub-triangular inner margin outline, defines a carapace shape that is distinct from that of rotund species of Loxocythere (loxocythere) Hornibrook, 1952 and Antarctiloxoconcha Hartmann, 1986. The type species of Antarctiloxoconcha – A.frigida (Neale. 1967), possesses internal carapace features that are very similar to the type species of Loxocythere - L. crassa Hornibrook, 1952. Both have relatively short carapaces and sub-quadrate inner margin outlines with posterior extremities in both valves positioned below mid carapace height. Species of Loxocythere (Novoloxocythere), in particular L. (N.) kerryswansoni, have a carapace shape that is transitional between Loxocythere and Loxoreticulatum Benson, 1964. Species of Loxoreticulatum generally possess a sub-parallelogram shaped carapace/inner margin and arched median hinge element. The latter feature is distinct from the mostly straight median hinge elements of Loxocythere (Loxocythere) and Loxocythere (Novoloxocythere) species. Species of Loxocythere (Novoloxocythere) are also readily distinguishable from relatively elongate species of Loxocythere, such as L. (L.) hornibrooki McKenzie, 1967, as the latter possess long (for genus), sub-rectangular shaped carapaces/inner margin outlines and posterior extremities below mid height.

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The concentrations of 12 trace metals were assessed in wild and cultured specimens of blacklip abalone, Haliotis rubra, from each of two sites, Geelong and Port Fairy, in Victoria, Australia. Cadmium, copper, iron and zinc were quantified in the foot muscle of specimens from all four populations but the concentrations of aluminium, arsenic, beryllium, chromium, lead, manganese, nickel and vanadium were below the detection limits of the instrumental techniques employed. When similar sized specimens from each population were compared, the concentrations of each of the quantifiable metals varied according to location. The Geelong wild population had the highest or equal highest concentrations of each metal. Metal concentrations in the wild populations were usually greater than or equal to the concentrations in the corresponding cultured population. The concentrations of the regulated essential elements, copper and zinc, decreased with an increase in abalone length whereas the concentrations of iron, manganese and cadmium were independent of length. Metal concentrations in H. rubra from all sites complied with the Australian Food Code and other standards of food safety.


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The diet and feeding of sea sweep (Scorpis aequipinnis) was investigated from 230 specimens collected from the south-western Victorian coastline between January and July, 2002. Stomach content analysis indicated that S. aequipinnis are browsing omnivores (55.6% algae, 25.4% animal, by dry weight), with rhodophytes found to be the most important component of their diet (93.5% frequency of occurrence; 42.6% dry weight; 45.5% prey-specific abundance). However, the relative proportions of the major dietary components differed significantly between size classes. The dietary composition of small individuals ( < 150 mm total length) was significantly different to larger individuals, primarily due to a higher degree of carnivory exhibited by the smaller fish. S. aequipinnis were found to be highly flexible feeders exploiting both benthic and pelagic food resources, characterised by irregular periods of selective carnivorous feeding.

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Egg cases from nine skate species occurring in Tasmanian waters were examined and measured. A species-specific identification key is provided for eight of these species. The key was developed primarily from fresh egg cases dissected from the oviduct, although specimens collected from the ocean floor or found dried on the beach were also used to test the key. Egg cases for the ninth species could not be included because the only egg case pair recovered was partially fomled. A diagnosis of the posterior end of this egg case is provided.

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Monitoring Ecological Impacts provides the tools needed to design  assessment programs that can reliably monitor, detect and allow  management of human impacts on the natural environment. The procedures described are well-grounded in inferential logic. Step-by-step guidelines and flow diagrams provide clear and useable protocols, which are applicable to real situations.

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The Western Antarctic Peninsula (WAP) is a biologically rich area supporting large standing stocks of krill and top predators (including whales, seals and seabirds). Physical forcing greatly affects productivity, recruitment, survival and distribution of krill in this area. In turn, such interactions are likely to affect the distribution of baleen whales. The Southern Ocean GLOBEC research program aims to explore the relationships and interactions between the environment, krill and predators around Marguerite Bay (WAP) in autumn 2001 and 2002. Bathymetric and environmental variables including acoustic backscattering as an indicator of prey abundance were used to model whale distribution patterns. We used an iterative approach employing (1) classification and regression tree (CART) models to identify oceanographic and ecological variables contributing to variability in humpback Megaptera novaeangliae and minke Balaenoptera acutorstrata whale distribution, and (2) generalized additive models (GAMs) to elucidate functional ecological relationships between these variables and whale distribution. The CART models indicated that the cetacean distribution was tightly coupled with zooplankton acoustic volume backscatter in the upper (25 to 100 m), and middle (100 to 300 m) portions of the water column. Whale distribution was also related to distance from the ice edge and bathymetric slope. The GAMs indicated a persistent, strong, positive relationship between increasing zooplankton volume and whale relative abundance. Furthermore, there was a lower limit for averaged acoustic volume backscatter of zooplankton below which the relationship between whales and prey was not significant. The GAMs also supported an annual relationship between whale distribution, distance from the ice edge and bathymetric slope, suggesting that these are important features for aggregating prey. Our results demonstrate that during the 2 yr study, whales were consistently and predictably associated with the distribution of zooplankton. Thus, humpback and minke whales may be able to locate physical features and oceanographic processes that enhance prey aggregation.

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The concentrations of heavy metals in the edible tissue of commonly fished species of the Victorian coast of Australia are reported. The metals studied were As, Cd, Cu, Hg, Pb, Se, and Zn and the fish species examined were snapper (Pagruss auratus), flathead (Platycephalus bassenssis and Neoplatycephalus richardsoni), lobster (Jasus edwardsii), and abalone (Haliotis rubra). None of the fish species studied had average concentrations exceeding the maximum levels specified for As, Cd, Hg, and Pb by the Food Standards Australia and New Zealand Food Standards code. Additionally, the concentrations of Cu, Se, and Zn were close to or below the median values generally expected in these species. Essential trace elements Se and Zn were found to be well regulated by all fish species. Although also essential, Cu was not so well regulated, especially in abalone. Nonessential metals As, Cd, and Hg are not regulated in the studied fish and their concentrations in the fish tissue are dependent on size and fishing zone. Metal concentrations were not largely affected by sex. Surprisingly, the concentrations of metals in fish in Port Phillip Bay, a zone, which includes the major cities of Melbourne and Geelong and is known to have high concentrations of metals in the water and sediment, were not consistently higher than those in other less-populated fishing zones.

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The Victorian Marine Mapping Project will improve knowledge on the location, spatial distribution, condition and extent of marine habitats and associated biodiversity in Victorian State waters. This information will guide informed decision making, enable priority setting, and assist in targeted natural resource management planning. This project entails benthic habitat mapping over 500 square kilometers of Victorian State waters using multibeam sonar, towed video and image classification techniques. Information collected includes seafloor topography, seafloor softness and hardness (reflectivity), and information on geology and benthic flora and fauna assemblages collectively comprising habitat. Computerized semi-automated classification techniques are also being developed to provide a cost effective approach to rapid mapping and assessment of coastal habitats.

Habitat mapping is important for understanding and communicating the distribution of natural values within the marine environment. The coastal fringe of Victoria encompasses a rich and diverse ecosystem representative of coastal waters of South-east Australia. To date, extensive knowledge of these systems is limited due to the lack of available data. Knowledge of the distribution and extent of habitat is required to target management activities most effectively, and provide the basis to monitor and report on their status in the future.

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Since 1989, and in comparison to the global trend, inland aquaculture production of European finfish has declined. To date, the yearly European freshwater aquaculture production is 371,727 tons, valued at over US$1 billion. Indigenous species accounted for less than one-third of the production, whereas alien species (a species that has been moved beyond its natural range of distribution) accounts for the remainder. However, in general, indigenous species command a higher market price. Currently, food quality and food safety are leading concerns of consumers, and European consumers are also becoming alert to environmentally detrimental practices. Therefore, to aim at economic sustainability, the sector needs to satisfy consumer expectations of environmentally friendly practices. It is believed that farming alien finfish species can threaten local biodiversity through escapes, and this represents a current environmental concern relative to aquaculture. In this context, an attempt is made in this paper to understand and quantify the impacts of alien finfish cultivation in European inland waters, and to suggest remedial measures.

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An evaluation of the effectiveness of Marine Protected Areas (MPAs) in temperate waters of Australasia has been conducted for this thesis. The aim was to identify key elements needed in a strategy for establishment and management of MPA’s in temperate waters of Australasia. This aim was achieved by assessing how effective a sample of MPA’s has been in meeting the conservation objectives for their establishment and by identifying factors that have contributed to success or failure of the MPA’s in meeting these objectives. Particular attention was paid to the objectives of ecological sustainability and biodiversity preservation. A MPA for the purposes of this research was defined as an area of coastal or marine environment, with a substantial subtidal component, set aside by law primarily for conservation purposes. The study region encompassed the coastal zones of Victoria, Tasmania and South Australia (Australia) and New Zealand. The questions posed in order to address the aim of this thesis were; a) Have existing MPA’s been effective in achieving conservation objectives? b) What have been the important influences on effectiveness of existing MPA’s? c) What are the key elements required for implementation of effective MPA’s? The thesis is divided into three parts. Part I is a review of the literature on implementation and effectiveness of MPA’s. Part II presents a detailed evaluation of one MPA: Point Lonsdale Marine Reserve (PLMR), Victoria, Australia. Part in is an evaluation of a number of Australasian temperate MPA’s based on information provided in a survey of people involved in management of MPA’s, and from a variety of published and unpublished documents. The MPA’s are described, evidence about ecological effectiveness is presented and factors that have enhanced and limited the ability of these MPA’s to achieve conservation objectives are derived. A substantial amount of scientific evidence was found for increases in abundance, mean size and size range of fish and invertebrate populations within the boundaries of ‘no-take’ MPA’s, Some evidence was found for ‘spillover’ of adults and juveniles into adjacent fishing grounds. Ecological effects detected within ‘no-take’ MPA’s in Australasia matched those described in the literature. The abundance and mean size of a number of previously exploited species have increased, migration into adjacent fishing grounds has been documented, and species richness has increased in at least one MPA. The PLMR was established primarily to protect the scientifically significant intertidal rock platforms. The results of the case study suggest that this objective has been achieved. Opinions about effectiveness were obtained for 28 MPA’s. Of these 19 were considered to be achieving some objectives and 10 were considered to be performing well in terms of overall ecological effectiveness. Positive effects on biodiversity were generally assumed as a result of reduction of damaging anthropogenic effects on habitat. Many questionnaire respondents noted an increase in community awareness about and support for marine conservation as a result of proclamation of MPA’s, Overall, the results support the value of MPA’s for sustainability of fish stocks and preservation of biodiversity, but there is substantial doubt over whether some of the MPA’s are too small to maintain benefits in the long-term. ‘No-take’ MPA’s, particularly those more remote from the impacts of human activities, have been the most effective in achieving objectives. A number of interacting factors important to eventual success of MPA’s were identified. The most important enhancing factors identified for the PLMR were physical attributes that limit the extent of human use and a strong conservation ethic amongst many of the visitors to this marine reserve. Limiting factors were far more numerous. Of most concern is the inadequacy of at-site management. Almost half of visitors to the area were not aware of its marine reserve status, despite the fact many were frequent visitors. The need for better educational and interpretative material on-site is highlighted by the results of the PLMR visitor survey. A total of 56 factors that have enhanced effectiveness and 46 factors that have limited effectiveness of Australasian temperate MPA’s were identified. A number of factors were important in more than one MPA and this was used to derive a set of critical, or key, factors. For example, a conclusion of all three approaches used in this study is that failure to implement day-to-day management through lack of resources was a major constraint on effectiveness. The importance of MPA’s to marine conservation depends, in part, on how well they are managed. The key factors that influence MPA effectiveness were used as the basis for derivation of the main requirements for implementation of MPA’s that will be capable of meeting the objectives for their establishment. The most important needs are: • that ‘no-take’ areas surrounded by buffer zones form the basis for a system of MPA’s; • that a high level of protection is bestowed by legislation and regulations; • that a minimum size be set for the ‘no-take’ core areas; • that the selection of sites for MPA’s takes into account land-based impacts; • that institutional arrangements are developed specifically for MPA’s; • that funding for MPA’s is increased to enable effective management; • that day-to-day management is implemented in all MPA’s, with enforcement and education programs as priority areas; • that a monitoring program for one or more MPA in each 'State' is established to provide evidence of ecological effects of reservation; • that public and stakeholder involvement in development and implementation of MPA’s is encouraged as this will influence the degree of public support and compliance; • that community-based programs to educate the general public, stakeholders, the media and decision-makers about the value of MPA’s are essential; and • that measures to reduce financial impact on affected stakeholders be implemented.

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Resin acids are reported to be of major toxicological importance in pulp mill effluents for Rainbow Trout. Their determination, using a high performance liquid chromatographic method, is described.