bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Hypoxia on Oxygen consumption by two species of Freshwater Mussel (Unionacea: Hyriidae) from the River Murray
Authors: Sheldon F , Walker KF
Published: November 2005

The mussel Alathyria jacksoni typically occurs in the main rivers of the Murray-Darling Basin and not in slow-flowing or standing waters. Conversely, Velesunio ambiguus is typical of billabongs and creeks and rarely occurs in big rivers except in the vicinity of impoundments. The exclusion of V. ambiguus from the main rivers probably reflects its weak anchorage, whereas the exclusion of A. jacksoni from billabongs may reflect its inability to withstand low levels of oxygen (hypoxia). At normal oxygen levels the mean rates of oxygen consumption for A. jacksoni and V. ambiguus are 21.5 (s.d. = 6.43, n = 17) and 13.5 (s.d. = 5.85, n = 10) �mol g-0.75 (dry tissue) h-1, respectively (a body-mass exponent of 0.75 was included in calculations of the mass-specific oxygen consumption rate). When exposed to declining oxygen, A. jacksoni shows little or no regulatory ability, whereas V. ambiguus maintains a steady rate of oxygen consumption down to 65 torr. Under extreme hypoxia, A. jacksoni loses muscular tone but V. ambiguus closes its values and remains inactive. On removal from water A. jacksoni incurs a significant oxygen debt after 10 days, but V. ambiguus shows no oxygen debt after 15 days. In general, animals adapted to lotic environments may need more oxygen, and may be more susceptible to hypoxia, than those adapted to lentic environments.
Variation in the life History of Diadromous and Lanlocked populations of the Spotted Galaxias, Galoxias truttaceus Valenciennes, in Tasmania
Authors: Humphries P
Published: November 2005

Variations in life history traits such as age class distribution, growth, gonadal development, reproductive investment and spawning time were studied in two stream-dwelling diadromous and two landlocked freshwater lake populations of the spotted galaxias, Galaxias truttaceus, in Tasmania. Whereas stream populations were dominated by 0+, I+ and 2+ age-class fish, lake populations had a smaller proportion of these younger individuals and a larger proportion of age classes older than 2 +. Growth in both lake and stream populations was slow over winter and more rapid during spring and summer. The majority of fish of both sexes matured at age two, irrespective of size, although some lake-dwelling males matured in their first year. Gonadal development commenced at the beginning of summer (December) in all populations. Spawning in stream-dwelling populations occurred before winter (May) and was associated with decreasing water temperature and photoperiod. By contrast, landlocked populations spawned in early spring (September), at which time both temperature and photoperiod were increasing. At spawning, landlocked females invested more energy in reproduction than did riverine females. This appeared to be a function of larger egg size in females from one lake population and greater fecundity in females from the other. Although G. truttaceus fits the general life-history model for diadromous galaxiids, having relatively large numbers of small eggs, the shift in spawning time for landlocked populations, and the inter-population variations in egg size and fecundity suggest considerable flexibility in the characteristics of this species' life history.
Impact of timber harvesting and production on streams: A review
Authors: Campbell IC , Doeg TJ
Published: November 2005

Timber harvesting operations have significant effects on both water quantity and water quality. The effects on water quantity have been well documented both in Australia and elsewhere. The effects on water quality are less widely appreciated, and include elevated concentrations of dissolved salts, suspended solids and nutrients, especially during peak flow periods. Several Australian studies have failed to measure peak flow transport of suspended solids, or have measured it inadequately, thus severely underestimating transport. The major short-term effects of timber harvesting on the aquatic biota result from increased sediment input into streams or increased light through damage to, or removal of, the riparian vegetation. Sediment which settles on, or penetrates into, the stream bed is of more concern than suspended sediment, and can lead to long-term deleterious changes to fish and invertebrate populations. Increased light causes an increase in stream primary production which may increase invertebrate densities, and alter community composition. These biological consequences have not yet been adequately investigated in Australia. Longer-term effects, as yet not investigated in Australia, include changes to stream structure as the regrowth forest has fewer large logs to fall into the stream. These large logs play a major role as habitat and retention structures in streams. There has been no attempt to evaluate the effects of timber production activities, including pesticide use and fuel reduction burning, on the Australian stream biota. Likewise, although buffer zones are widely advocated as a protection measure for streams in Australia, there have been no studies to evaluate their effectiveness.
Current-Shelf interactions during the Australian Coastal experiment
Authors: Louis JP
Published: November 2005

Current-meter records from the Australian Coastal Experiment are examined. In addition to the long, coastal-trapped waves with λ > 800 km that this experiment was specifically designed to investigate, the current records also show distinct event-like bursts of wave activity. These events appear to be related to offshore current structures and are observed over the slope as low-frequency current oscillations with periods of 3-5 days and lasting for 3-4 cycles. It is postulated that these topographic waves are generated by the interaction of the East Australian Current and associated eddies with the sloping topography of the East Australian shelf region. Outside the intensely nonlinear region where these waves are initially generated, they take on the appearance of a set of dispersing internal shelf waves.
Larval descriptions of the Hydrobiosidae, Philopotamidae, Hydropsychidae and some Ecnomidae (Trichoptera) from South-western Australia, with notes on Biology
Authors: Dean JC , Bunn SE
Published: November 2005

At least 51 species of Trichoptera, in 10 families, are now known from south-western Australia. Larvae of the Hydrobiosidae, Philopotamidae, Hydropsychidae and some species of Ecnomidae are briefly described, and notes on their distribution and biology are presented. A key to species is also provided for the larvae of most families of Trichoptera recorded from this region.
High incorporation of esential fatty acids by the Rotifer Brachionus plicatilis fed on the Prymnesiophyte Alga Pavlova lutheri
Authors: Nichols PD , Holdsworth DG , Volkman JK , Daintith M , Allanson S
Published: November 2005

The lipid and fatty acid compositions of rotifers (Brachionus plicatilis) fed on yeast or on the unicellular prymnesiophyte Pavlova lutheri, an alga commonly used in Australian hatcheries, were compared by TLC-FID, GC and GC-MS. Significantly higher relative proportions of energy-rich triacylglycerol were present in the Pavlova-fed rotifers than in the yeast-fed animals, and total lipid content reached a maximum between 12 and 24 h. High incorporation of the essential fatty acids eicosapentaenoic acid (EPA; 20: 5ω3) and docosahexaenoic acid (DHA; 22:6ω3) occurred in the Pavlova-fed rotifers. EPA and DHA content was 11.6% of total fatty acids after 3 h of feeding and reached 20 and 23% after 24 and 48 h respectively. The proportion of essential fatty acids in rotifers fed Pavlova compares very favourably with data obtained by overseas workers using a variety of microalgae and dietary supplements. On the basis of fatty acid composition alone, these results confirm the suitability of P. lutheri as a feedstock for Australian mariculture operations.
Feeding biology of Caranx bucculentus Alleyne and Maclay (Teleostei: Carangidae) in Albatross Bay, Gulf of Carpentaria, with special reference to predation on penaeid prawns
Authors: Bewer DT , Blaber SJM , Salini JP
Published: November 2005

Caranx bucculentus is an abundant predator in the commercial prawn grounds of Albatross Bay in the Gulf of Carpentaria. The stomachs of samples taken from Albatross Bay contained mainly teleosts (48%) and crustaceans (46%), with commercially important prawns contributing 15% by dry weight to the total diet. The proportion of teleosts, penaeids, brachyurans, 'other crustaceans' and molluscs in the diet changes as the fish grow and their diet shifts from mainly crustaceans to mainly teleosts. Although the percentage of teleosts, penaeids, brachyurans and 'other crustaceans' eaten varied with the time of sampling, no seasonal variation was noted. Only the numbers of penaeids and 'other crustaceans' eaten varied significantly over 24 h. Caranx bucculentus less than 200 mm SL ate most penaeid prey during the day and primarily took small, commercially unimportant species. In contrast, fishes more than 275 mm long took larger, commercially important species, and mainly at night. The abundance of large C. bucculentus and the high incidence of commercial penaeids in their diet indicate that this species may have a considerable impact on the prawn resources of Albatross Bay.
Age and growth of Freshwater Herring, Potamalosa richmondia Macleay (Clupeidae: Hyperlophinae), in the Bellinger River, NSW
Authors: Pidgeon RWJ
Published: November 2005

The freshwater herring, Potamalosa richmondia Macleay, is a catadromous fish that inhabits coastal rivers of New South Wales. Estimates of the age and growth of this species in the Bellinger River were made from scales. Comparison of scale ages with those from whole otoliths and burnt otolith sections from a sample of 30 fish aged at 2 to 8 years resulted in a 73 and 79% exact agreement and a 97 and 100% agreement within one year, respectively. Marginal-increment analysis of the scales indicated that the annulus was formed during the winter, which is also the spawning season. The ageing method was validated for age classes of 2 to 8 years by these procedures. The age at the first annulus and at ages 9 to 11 years could not be validated. The oldest fish examined was estimated to be 11 years old. The growth rate was very slow in comparison with that of other clupeids. Parameters of the von Bertalanffy growth equation, based on lengths and ages at capture, were L∞ = 252.7 mm, K = 0.126, and t0 = -2.77 years. There was no difference between the sexes in their growth in length. However, the length-weight relationships of males and females were different, with females longer than 180 mm weighing more than males of the same length. The predicted weights at the asymptotic length were 213.2 g for males and 257.6 g for females.
An experimental study of Phototactic responses of Tanytarsus barbitarsis Freeman (Diptera: Chironomidae
Authors: Kokkinn MJ , Williams WD
Published: November 2005

A series of salt lakes near Port Augusta, South Australia, supports large larval populations of Tanytarsus barbitarsis Freeman, a chironomid midge. When adults emerge they often fly to nearby artificial lights, and when large numbers do so a considerable nuisance to local residents is caused. In an investigation designed to provide control advice, those parts of the spectrum of particular attractivity to adults were identified in an experimental study of phototactic responses. Results indicated that the peak of attractivity lies in the near-ultraviolet part of the spectrum (370-400 nm). A second, weaker peak lies between 490 and 510 nm. Light intensity does not appear to be important. Certain sorts of commercially available lamps emit light with peaks in those parts of the spectrum attractive to T. barbitarsis and may be suitable for control purposes.
Manipulation of fishing effort in Australia's penaeid Prawn Fisheries
Authors: Somers IF
Published: November 2005

The potentially detrimental side-effects of prawn trawling are coming under increasing scrutiny in Australian waters, particularly in such ecologically sensitive areas as Queensland's Great Barrier Reef, and various restrictive measures are being suggested. Before changes are imposed on the prawning industry, the effects of trawling on the target prawn species and the long-term management of these effects need to be fully understood. Using a simulation model of a simplified prawn fishery, this paper describes the basis for the current regulatory mechanisms for Australian's prawn fisheries, in particular the manipulation of both the level and pattern of fishing effort. It is shown that even in moderately fished stocks, the fishery manager has several options, such as seasonal and nursery area closures, that are consistent with the goal of minimizing the impact of prawn trawling, while in no way penalizing the industry economically. With these in mind, possible ways of resolving or reducing the conflict with groups outside the prawning industry are discussed.
By-catch from Praen trawling in the Hawkesbury River, New South Wales: Species Composition, distribution and Abundance
Authors: Gray CA , McDonall VC , Reid DD
Published: November 2005

This study examined spatial and temporal variability in the composition, distribution and relative abundance of by-catch from prawn trawl sampling in the Hawkesbury River, New South Wales. It also determined whether there were differences in the fauna between sections of the river that are open and closed to prawn trawling. By-catch was sampled monthly between March 1986 and February 1988 in three areas along the river that differed in distance from the mouth of the estuary and in salinity. The total incidental catch comprised 75 species of fish, 13 species of crustaceans and 5 species of molluscs: 42 species were commercially and/or recreationally important. Classification and ordination analyses showed that the species composition of the by-catch differed between the area closest to the mouth of the estuary and that furthest upstream, and that this difference was relatively consistent throughout time. The number of species in the by-catch decreased with increasing distance upstream. Annual and seasonal changes in the number of species were similar in all areas along the river: more species were caught in 1987 than in 1986, and in autumn and winter each year. In contrast, the number of individuals caught differed among areas and these differences varied between years. Similarly, seasonal fluctuations in the numbers of individuals caught varied between years, but these variations were similar in all areas. In the area furthest upstream there were no apparent differences in the numbers of species and individuals caught by prawn trawl sampling in sections of the river open or closed to prawn trawling.
Review of the effects of trawling on Macrobenthic Epifaunal communities
Authors: Hutchings P
Published: November 2005

This review summarizes the available information on the macrobenthic epifaunal communities in tropical areas of Australia, with regard to species composition and seasonal changes in these com- munities. A synopsis is given of the information available on their growth rates and reproduction, together with a consideration of the role they play within tropical marine communities. Little is known about this role. Changes in the composition of these communities that occur as a result of trawling are discussed, together with the factors that must be considered before plans of management can be drawn up and implemented. There is a paucity of information on macrobenthic epifaunal communities and their role in Australian tropical marine ecosystems.
Changes in the stock composition and abundance of spawning Gemfish Rexea solandri (Cuvier), Genpylidae, in South-eastern Australian waters
Authors: Rowling KR
Published: November 2005

Data collected during a study of the New South Wales trawl fishery showed a marked increase in landings of gemfish Rexea solandri (Gempylidae) during the late 1970s, which was due to the exploitation of winter spawning aggregations. Catches peaked at 5100 t in 1980, but declined to about 3000 t over the following few years, rising again to around 4000 t in 1987. Daily landings data for individual vessels were analysed for the period 1973-86. Fishing effort (target days) was standardized by comparison of each vessel's catch per target day with that of an arbitrary standard vessel. Catch per standard day declined by about 70% between 1980 and 1983. The mean caudal fork length of gemfish from spawning run catches declined from 79 cm to 71 cm over the period 1975-85, reflecting a reduction in the number of large fish in the catch and the recruitment of smaller fish into the spawning aggregations. Ages of gemfish were estimated from counts of hyaline zones on the sagittal otoliths. For age classes 1 to 3, otolith-determined ages were validated by means of modal analysis of monthly length-frequency data, but no validation was possible for the older age classes. Males sampled from spawning-run catches were estimated to be predominantly 4-8 years of age, with a maximum age of 11, whereas females were estimated to be predominantly 5-10 years old, reaching a maximum age of 16. For each sex, the proportion of older fish in the catch declined between 1980 and 1986, and there was a corresponding increase in the prominence of newly recruited age classes. It was concluded that there had been a substantial decline in the relative abundance of spawning gemfish, and that significant changes had also occurred in the size and age composition of the stock, consistent with the effects expected to result from exploitation.
Pilot studies for designs of surveys of human disturbance of intertidal habitats in NSW
Authors: Underwood AJ , Kennelly SJ
Published: November 2005

Data are presented from pilot studies as the first step in the design of large-scale surveys of the effects of human recreational activities on intertidal habitats in New South Wales. People visiting the seashore were counted and interviewed. Numbers of organisms removed for food or bait were determined, as were the numbers of fishermen and scavengers frequenting the shore. Data from pilot studies using these methods assessed the various effects of human recreation during school terms or holidays, on week-days or week-ends and on sunny or overcast days. Pilot sampling at different locations provided estimates of the variability from place to place within 30 km. Sampling was in a fully orthogonal design which allowed tests of various factors and their interactions. More people affected the shore during school holidays than during term-time, but there were no differences between week-ends and week-days. There were significant effects due to weather, with more potential impact occurring on sunny than on overcast days. There were also substantial differences in effects at different places. Other potential sources of variation which should be considered in designing surveys of the effects of human recreation are briefly considered. These include variability due to time of day, the state of the tide, prevailing weather and various spatial and temporal scales. Such pilot sampling enables the efficient design of the large-scale, long-term surveys that are a necessary prerequisite to determining the magnitude and effects of human disturbances and their eventual management.
Methods of Assessing Ovarian development in Fishes: a Review
Authors: West G
Published: November 2005

An important component of many studies of fish reproductive biology is the assessment of the stage of gonad development of individual fish. The methods in use vary from highly detailed to cursory, but there are few reviews of their reliability or usefulness. This review examines histology, measurements of oocyte size, staging based on the appearance of whole oocytes, staging based on the external appearance of the ovary, and gonad indices. Histology is the most accurate technique, but it is time- consuming and expensive. Staging based on the appearance of whole oocytes can be a useful alternative but may be inaccurate with oocytes in transitional stages of development. Staging based on the external appearance of the ovary is the simplest and most rapid method, but it may be subjective and its accuracy is uncertain. Oocyte size may be used as a predictor of developmental stage if the size ranges of the various stages are known, but the sizes of different oocyte stages may overlap, which complicates this approach. Oocyte size may be used on its own to measure development but gives little information on the physiological status of the ovaries. Gonad indices (gonad size relative to body size) provide a useful insight into changes in ovary size and complement results obtained using staging methods. However, gonad indices, like oocyte size, may be biased when samples of fish of different body sizes are compared.
Occurrence of Hypolimnetic blooms of the Purple Sulfur Bacterium, Thiopedia rosea, and the Green Sulfur Bacterium, Chlorobium limicola, in an Australian Reservoir
Authors: Banens RJ
Published: November 2005

Seasonal blooms of green and purple sulfur bacteria were found in the anoxic hypolimnion of Puddledock Reservoir, a small, eutrophic water-supply storage in north-eastern N.S.W. These blooms were dominated by the green sulfur bacterium C. limicola, and were sometimes overlain by a bloom of the purple sulfur bacterium T. rosea. They generally formed a plate just below the oxycline at a depth of between 4 and 6 m in the shallow, sulfuretted, nutrient-rich hypolimnion. The blooms increased in density from about mid summer until holomixis, when the return to oxygenated conditions killed the sulfur bacteria. Maximum bacterial chlorophyll levels varied with the light regime, but typically reached 250�g L-1, although the maximum recorded value was 410�g L-1. The Secchi transparency during summer stratification was variable, but was typically around 1.2 m, with extremes ranging from 4.5 m on one occasion to as low as 0.8 m for an extended period, as a result of epilimnetic algal levels of 40�g L-1 chlorophyll. Gilvin (g440) levels during these bacterial blooms were always less than 2.5 m-1. Sulfur bacteria were absent during one summer; this was attributed to a dramatic change in the light regime as a result of a major inflow event. The latter resulted in a Secchi depth of 0.75 m associated with very high gilvin levels of 7.5-11.0 m-1 and high inorganic turbidity levels, which would have resulted in a very dim red light regime in the hypolimnion. This study is the first report of a bloom of purple sulfur bacteria in Australian fresh waters, and the first to detail the occurrence of blooms of green and purple sulfur bacteria in a seasonally stratifying water body.
Physicochemistry and Vegetation of Piccaninnie Ponds, a Coastal Aquifer-fed Pond in South-eastern South Australia
Authors: Scholz O
Published: November 2005

The aquatic vegetation and physicochemistry of Piccaninnie Ponds are described and recent annual losses of aquatic vegetation investigated. The aquifer-derived waters of the Ponds are characterized by their clarity, low nutrient content, low salinity, and lack of thermal and chemical stratification. In 1985, large areas of aquatic vegetation within the Ponds degraded and were lost. Subsequent faster regeneration of denuded areas by Ruppia polycarpa resulted in the displacement of Lepilaena cylindrocarpa. The annual uprooting of R. polycarpa, which has occurred since, results from Ruppia's comparatively poorer anchorage capacity in the loose sediment floc. Gradual expansion of L. cylindrocarpa into freshly uprooted regions restricts the regrowth of R. polycarpa and hence the area susceptible to denudation in the following year. It is expected that the displacement of R. polycarpa will continue until only small isolated stands remain, which will be prevented from uprooting by the root matrix of surrounding vegetation.
Temperature inversions at intermediate depths in the Antarctic Intermediate waters of the South-western Pacific
Authors: Hamilton LJ
Published: November 2005

Deep (about 1000 m) marked temperature inversions and/or salinity reversals found in conductivity- temperature-depth profiles in the south-western Pacific for 1985 to 1987 are shown to arise from confluences of different branches of the Antarctic Intermediate Water (AAIW). Salinity reversals lead to the presence of several intermediate-depth salinity minima instead of the simple broad minimum in the vertical usually described as characterizing the presence of AAIW in this area. The anomalies are found at particular locations, often near ridges and rises. Significantly differing thermohaline properties acquired by the branches from mixing over separate travel paths apparently allows the formation of temperature inversions by isentropic penetrations. Some perturbations are dynamically caused in that at least one branch of AAIW is transported in association with strong surface currents with deep influence. Other confluences are caused by topographic control on AAIW flows moving independently of surface currents. Perturbations south of the Subtropical Convergence are related to the initial formation of the AAIW, but these are not of major interest in this analysis, being well known and simply explained. Locations of perturbations correspond in some areas to flow patterns of intermediate waters inferred by researchers using historical data, and they indicate other areas where the flow patterns need more investigation. Some comments are made on East Australian Current outflows from the Tasman and Coral Seas that have considerable influence on the flow of branches of the AAIW. Other remarks are made concerning the peculiarities of the temperature-salinity regime of the Tasman Front, which inhibits the formation of temperature inversions at depth. In general, the medium- and fine-scale structure in the central Tasman is that of the stepped type, with intrusive type in other areas.
Influence of surface gravity waves on wind-driven circulation in intermediate depths on an exposed coast
Authors: Black KP , McShane PE
Published: November 2005

Coastal experiments in 18 m depths showed the systematic reduction of wind-driven longshore currents in the presence of surface waves. Predicted wind-driven currents were found to be nearly an order of magnitude greater than measurements if the wave influence was neglected. However, satisfactory predictions were made when the increased effective bed friction due to the non-linear interaction between the waves and currents was accounted for. This paper assesses the applicability of wave/current interaction theory to natural open-coast environments. The results are relevant to the prediction of dispersal (e.g. of pollutants or larvae) on open coasts.
Squalene content and neutral lipis composition of Livers from Deep-sea sharks caught in Tasmanian waters
Authors: Deprez PP , Volkman JK , Davenport SR
Published: November 2005

Deep-sea sharks (mainly dogfish) are a significant by-catch of trawls for the deep-water fish orange roughy (Hoplostethus atlanticus). To test whether the livers of these sharks might be a source of commerically valuable squalene and other lipids, 16 sharks of 8 species were collected from Tasmanian waters at depths of 700-1200 m during research cruise S02/88 of FRV Soela. The sharks were Centroscyrnnus crepidater (longnose velvet dogfish), Centroscyrnnus owstoni (Owston's dogfish), Centroscyrnnus coelolepis (Portuguese dogfish), Deania calcea (shovelnose dogfish), Etmopterus baxteri (Baxter's dogfish), Etmopterus sp. nov. (unnamed dwarf dogfish), Dalatias licha (kitefin or seal shark) and Centrophorus squarnosus (leafscale gulper shark). Squalene content, triacylglycerols, diacylglyceryl ethers, total fatty acids, pristane and other lipids were analysed by capillary gas chromatography and thin-layer chromatography-flame ionization detection. The livers contained high levels of squalene (15-69% by weight), except for the liver of C. squarnosus (I%), which had an unusually high amount of diacylglyceryl ethers (79%). Triacylglycerol and diacylglyceryl ether contents in the livers ranged from 1 to 26% and from 7 to 79% by weight respectively. The C19 isoprenoid alkane pristane was a minor constituent in all samples (0.01-0.56% by weight of liver). The three major esterified fatty acids in all samples were palmitic (16:0), oleic [18: 1 (n - 9)] and eicosa-11-enoic [20: 1 (n - 9)] fatty acids. Polyunsaturated fatty acids were minor constituents. These data indicate that shark livers could provide a profitable by-catch from deep-water trawls, but it is unlikely that shark could form the basis for a target fishery due to their susceptibility to overfishing.
Partitioning of Lindane between sediment, water and the Crustacean Metapenaeus macleayi
Authors: Just AC , Hawker DW , Connell DW
Published: November 2005

The partitioning behaviour of lindane between sediment, water and the prawn Metapenaeus macleayi was investigated. The sediment-to-water partition coefficient was determined with sealed glass vials in laboratory experiments and found to be 9.52, or 2164 on an organic carbon basis. This is in agreement with relevant literature data and confirms that the organic matter of the sediment is the primary sorption site in this process. The bioconcentration factor was evaluated from laboratory experiments with prawns in sealed glass jars in which the lindane seawater solution was changed frequently. Under these conditions, effective equilibrium was attained after 24 h. Measured uptake (k1) and clearance (k2) rate constants were smaller than predicted on the basis of existing general relationships between k1, k2 and the octanol/water partition coefficient (Kow) for crustaceans. The bioconcentration factor (KB) was found to be 5.50, or 1273 on a lipid basis, which is also smaller than values estimated from general relationships. The sediment-to-prawn bioaccumulation factor was 0.58, which means that biotic concentrations will be significantly less than those observed in sediments.
Seasonal pattern and inferred phosphorus limitation of phytoplankton biomass in two tropical reservoirs in northern Australia
Authors: Townsend Simon A.
Published: November 2005

Manton River Reservoir (MRR) and Darwin River Reservoir (DRR) are two small
impoundments in the Australian wet/dry tropics. Over an eight-year period,
chlorophyll a concentrations in the mixed layer averaged
3.6 µg L−1 in DRR, and 7.1 µg
L−1 in MRR. The seasonal pattern of chlorophyll
a at MRR was influenced by wet season wash-out (February
average 4.8 µg L−1 ), and dry season
destratification and nutrient enrichment of the surface waters (July average
8.4 mg L−1 ). In contrast, DRR exhibited near
uniform chlorophyll a concentrations over the year. The
seasonal patterns of DRR and MRR chlorophyll a are
typical of tropical water bodies which tend to have a smaller annual range
than temperate lakes, though this can be modified by significant wash-out.
Empirical evidence suggests that the phytoplankton biomass of each reservoir
is phosphorus limited, relative to the potential provided by other nutrients
and light energy. This conclusion is based on a regression of total phosphorus
and chlorophyll a concentrations of pooled DRR and MRR
data (P < 0.001;
r2 = 0.90), and the high
total-nitrogen to total-phosphorus concentration ratios (by weight) of 50 and
37 in DRR and MRR, respectively. Annual chlorophyll a
and total phosphorus concentrations for both reservoirs are in accord with the
OECD regression for temperate lakes and reservoirs.
Heat contents, thermal stabilities and Birgean wind work in Dystrophic Tasmanian Lakes and Reservoirs
Authors: Bowling LC
Published: November 2005

Values of whole-lake standard energy parameters (heat content, thermal stability and Birge's work of the wind) for ten dystrophic standing waters from western Tasmania were lower than expected for lakes of their depth and area. Although controlled principally by morphometric factors, the degree of shelter from wind and the extent of each lake's dystrophy also had considerable effects. These factors allowed only surface waters to contribute to the annual heat exchange cycle, thereby reducing the magnitude of each lake's heat budgets and influencing stability and wind work values. The lakes show considerable short- and long-term fluctuations in heat content, stability and wind work values in response to the capricious maritime meteorological conditions of the area. However, long periods between successive samplings may have caused some underestimation of the ranges of these three parameters. Despite this, the study reveals that these standard energy parameters are effective in describing the annual energy input and resistance to wind-induced mixing of these dystrophic Tasmanian lakes.
Partitioning of unsubstituted Polycyclic Aromatic Hydrocarbons between surface sediments and the water column in the Brisbane River Estuary
Authors: Kayal SI , Connell DW
Published: November 2005

In all, 23 sediment samples and 8 water column samples from the Brisbane River estuary, Queensland, Australia, were analysed for polycyclic aromatic hydrocarbons (PAHs) in order to assess the field partitioning behaviour of these hydrocarbons. Twelve PAHs, ranging in molecular weight from naphthalene to benzo[a]pyrene, were identified and quantified. Their partition coefficients, indexed to sediment organic carbon and lipid content, were calculated after filtering to remove particulates and making a calculated adjustment for colloids, or organic matter, in the water phase. In logarithmic form, the partition coefficients were related to the physico-chemical properties of the compounds (Kow, Sw, RRT) by relationships having a parabolic shape rather than being linear. However, compounds with log Kow values of less than 5.5 gave linear relationships comparable to, but distinctly different from, those obtained from laboratory experiments. It is suggested that field conditions have distinctive differences from laboratory experiments that do not allow the direct translation of laboratory-based relationships to the natural aquatic environment.
210Pb/226Ra Disequilibria in Otoliths of Blue Grenadier, Macruronus novaezelandiae; Problems associated with Radiometric ageing
Authors: Fenton GE , Ritz DA , Short SA
Published: November 2005

Otoliths from blue grenadier (Macruronus novaezelandiae), which had been aged previously by annuli analysis, were analysed for the naturally occurring radionuclides 210Pb and 226Ra in an attempt to independently verify their age. However, the radiometric technique could not be applied to determine age because the results showed that 226Ra was not incorporated at a constant rate throughout the life of M. novaezelandiae. Uptake of 226Ra was greater in juveniles than in adult fish. This was probably due to the juvenile phase inhabiting inshore/estuarine waters.
Studies on Southern Australian Abalone (Genus Haliotis). XII. Long-term recruitment and mortality dynamics of an unfished population
Authors: Shepherd SA
Published: November 2005

The recruitment strength and natural mortality of an isolated, unfished population of the abalone Haliotis laevigata Donovan at West Island, South Australia, were estimated from 1970 to 1987. Recruitment, as judged by the appearance of 2-year-old abalone, varied widely from year to year, and the frequency of distribution of annual recruitment was found to be best fitted by a log-normal curve. No evidence was found that estimates of spawning stock size were a significant variable contributing to this variability. During the 18-year period, the population size oscillated up and down twice; the increases were due to successive years of strong recruitment, the declines to the dampening effect of density-dependent mortality, which ranged from 0.02 to 0.86 per annum. The changing mortality rates were attributed to the behavioural response of stingrays to abalone densities. Analysis of dead shells collected from the study site for 5 years indicates that stingrays may cause 70-94% of the total mortality of abalone 3 years and older and that octopuses, crabs and unknown causes are responsible for the remainder.
Robustness of classification and ordination techniques applied to Macroinvertebrate communities from the La Trobe River, Victoria
Authors: Marchant R
Published: November 2005

The robustness of site groupings produced by ordination (DECORANA) and classification (TWINSPAN) techniques to variations in the quality of the raw data was investigated, using two data sets on macroinvertebrate communities from the La Trobe River. Ordinations or classifications based on the presence or absence of species were not substantially different from those based on actual abundance levels. However, when taxonomic discrimination was reduced from the species (or genus) level to the family level, distortions occurred in the resulting ordinations and classifications. In addition, ordinations based on 10 replicates per sample were little different from those based on a subset of 5 or 6 of these replicates; fewer than 4 replicates did not adequately represent the patterns present in the full data set.
Macroalgae, in the Upper Yarra and Watts River catchments: Distribution and Phenology
Authors: Entwisle TJ
Published: November 2005

Studies on the floristics and phenology of macroalgal communities in the upper Yarra and Watts River catchments have shown that the urbanized reaches of the Yarra River near Warburton are relatively species-rich and that they include nearly all macroalgal taxa found in protected catchments upstream. The lower of three river sites near Warburton, however, includes fewer species and is seasonally dominated by Vaucheria bursata, a saproxenous alga. The macroalgal communities on solid rock are distinct from those on loose rock subject to flood movement, and they include more taxa with basally attached filaments. A nearby enriched tributary, McMahons Creek, is dominated by a Spirogyroideae species and is species-poor. Species richness is also low on small-weirs and natural stream habitats in protected upstream catchments. Experimental timber harvesting above a series of small-weirs introduced weed species into the streams, replacing some of the native macroalgal species. Indigenous macroalgal species return 5 or so years after selective timber thinning, but they do not return even 10 years after clear-felling and fertilizing. The macroalgae of the upper Yarra River basin can be grouped into those that can grow throughout the year, those whose growth is restricted by water temperature, and those with a distinct seasonality unrelated to water temperature.
Clinotactic responses of Larval Silver Perch (Bidyanus bidyanus) and Golden Perch (Macquaria ambigua) to simulated environmental gradients
Authors: Gehrke PC
Published: November 2005

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.
Effect of temperature on the Emergence, activity and feeding of male and female Sand Crabs (Portunus pelagicus)
Authors: Sumpton WD , Smith GS
Published: November 2005

The effect of temperature on emergence, activity and feeding of the sand crab, Portunus pelagicus (L.), was measured under laboratory conditions. Crab emergence was greatest at night, particularly shortly after dusk. Males were significantly more active than females, but the activity of both sexes declined with falling temperature. There were no significant differences in the amount of food consumed by male and female P. pelagicus within the temperature range 16.5-26�C. It was concluded that sexual differences in catchability, as a result of differential activity and feeding, were not responsible for the seasonal changes in catch per unit effort of male and female P. pelagicus in the Moreton Bay trap fishery.
Bathymetric distribution and behaviour of two Sympatric species of Oligometra (Echinodermata: Crinoidea) at Lizard Island, Great Barrier Reef
Authors: Vail L
Published: November 2005

Two sympatric crinoid species of the genus Oligometra are abundant on fringing reefs surrounding Lizard Island. Both species were present over all depths investigated. O. serripinna was most abundant in shallow water (6-19 m), and O. carpenteri in deeper water (22-25 m). Variation in behaviour between these two species includes differences in feeding periods and orientation of arms during daylight hours.
Is the rate of Embryonic development a predictor of overall development rate in Tanytarsus barbitarsis Freeman (Diptera: Chironomidae)?
Authors: Kokkinn MJ
Published: November 2005

Mathematical relationships describing the effect of water temperature on embryonic development and generation time for Tanytarsus barbitarsis, a nuisance chironomid from salt lakes near Port Augusta, South Australia, were compared. The aim of the comparison was to determine whether the relation- ship describing egg hatching could be extrapolated to determine the overall development rate of the species. Results indicated that the power function that closely described embryonic development, D(t) = 8712.32t-2.70, could not be fitted to the generation-time data. However, when an additional term, water salinity, was included, a highly significant relationship was derived: D(s,t)*=S4.0308t-4.471. This suggested that laboratory egg-hatching experiments could not account for the attenuating effect of environmental factors on overall development rates in the field.
Optical properties, of waters in the Murray-Darling Basin, South-eastern Australia
Authors: Oliver RL
Published: November 2005

Apparent and inherent optical properties were determined for a range of water types in the Murray- Darling basin by using a combination of field and laboratory techniques. The absorption coefficient was calculated directly from in situ irradiance measurements of photosynthetically active radiation, whereas the scattering coefficient was determined from the irradiance measurements in conjunction with published nomograms relating the apparent and inherent optical properties. The validity of the nomograms for use in these waters was confirmed by comparing values of the average cosine calculated directly from in situ measurements with those estimated from the nomograms. These were closely correlated except for sites with chlorophyll concentrations greater than 200 mg m-3. The scattering coefficients estimated from the nomograms were approximately numerically equal to the turbidity in nephelometric turbidity units, but the variability of the relationship made it unsuitable for checking the validity of the nomograms. The relative role of dissolved and particulate components in the absorption and scattering of irradiance was examined by using spectrophotometry and linear regression of inherent optical properties on concentrations of the components. Estimates of specific absorption and scattering coefficients for algae, non-chlorophyllous suspended particles, and dissolved yellow colour were comparable to similar coefficients reported in the literature. The relative importance of these components to absorption and scattering varied considerably between sites and demonstrated the need for information on inherent optical properties in understanding the factors causing changes in optical water quality.
An incident of Southern Occean oil pollution: Effects of a spillage of diesel Fuel on the rocky shore of Macquarie Island (Sub-Antarctic)
Authors: Pople A , Simpson RD , Cairns SC
Published: November 2005

On 3 December 1987, the Australian resupply ship Nella Dan ran aground at Macquarie Island, releasing approximately 270 000 L of oil, mostly light marine diesel, into the sea. This represented one of the few spills to have occurred in southern hemisphere cold waters. Following the spill, thousands of marine invertebrates were washed up dead on beaches along 2 km of the shore. Twelve months after the spill, a study was conducted to examine the shore community in 5 zones at 2 oil- affected and 2 control locations. Three sites were examined within each of these locations. Densities of marine invertebrates appeared to have been markedly reduced in the lower littoral and sublittoral zones in the vicinity of the wreck. In the upper littoral zones, algal cover and invertebrate abundance were similar at oil-affected and control locations. The significance of the spill and its long-term effects are discussed.
Efficiency estimates of a stream Benthos suction sampler
Authors: Growns IO
Published: November 2005

The efficiency of a modified Boulton suction sampler was tested in 2 riffle zones, using multiple
removals. Macroinvertebrate fauna was sampled with approximately 70% efficiency on first removal,
while organic matter was sampled with 55% efficiency. Sampling efficiencies for specific taxa ranged
from 86% (Plecoptera) to 66% (Chironomidae) and 59% (Trichoptera). The results of this study
indicate that sampling efficiency can be improved either by taking multiple samples at one location
or by increasing the time spent disturbing the substratum and pumping water from the stand pipe.
The results also indicate the importance of conducting pilot studies to determine the efficiency of a
sampler at sites where the efficiency is likely to be different.
Biology of the Nightfish, Bostockia porosa Castelnau, in a South-western Australian River
Authors: Pen LJ , Potter IC
Published: November 2005

The biology of the nightfish, Bostockia porosa, is described on the basis of data obtained from monthly samples collected from the southern branch of the Collie River in south-western Australia during 1984, 1985 and 1988. It is estimated that most of the 2463 fish caught during those years belonged to either the 0+ (81.8%) or 1 + (12.5%) age classes. Representatives of the 2+ and 3+ age classes contributed 4.2 and 1.0% respectively, and one fish as old as 6+ was found. The parameters of the von Bertalanffy growth curves (La∞ K and to) were, respectively, 92, 0.818 and -0.151 for males and 104, 0.669 and -0.176 for females. The lengths attained at the end of the 1st, 2nd and 3rd years of life were, respectively, 56 mm (- 1.8 g), 76 mm (-4.5 g) and 85 mm (-6.3 g) for males and 56 mm (-1.8 g), 79 mm (-5.1 g) and 91 mm (-7.8 g) for females. Sexual maturity was attained by most males (61.4%) at the end of the 1st year of life but not by females until the end of the 2nd year of life. The great majority of fish migrated into tributary creeks when these started to flow in the winter. Spawning occurred in the creeks during late August and early September, when freshwater discharge was still high and temperatures and daylight length had just begun to increase. Fecundity ranged from 230 to 1138, with a mean (�1 s.e.) of 608 � 49.1. Bostockia porosa is carnivorous, feeding on a wide range of benthic organisms, particularly ostracods and dipteran larvae. In contrast to Galaxias occidentalis, another abundant endemic species in the Collie River, B. porosa is more active during the night than during the day, spawns 1 month later, and feeds mainly on benthic fauna rather than terrestrial and planktonic fauna.