bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimates of annual production for some aquatic insects from the La Trobe River, Victoria
Authors: Marchant R
Published: November 2005

Annual production was estimated by the size-frequency method for Ephemeroptera (Tasmanocoenis
tonnoiri, two species of Baetis, Atalonella spp., Atulophlebioides sp.), Plecoptera (Leptoperla spp.) and
Trichoptera (Ecnomus sp.) at four sites on the lowland section of the La Trobe River. Annual production
(P) of individual ephemeropteran species (or genera) varied from 0.02 to 0.7 g m-2 while total annual
production of this order at two sites was 0.7-1 . 5 g m-. Annual production of Leptoperla spp. was
0.03 g m-2 at one site while Ecnomus sp, averaged 2 g m-2 at two sites. Estimates of annual production
were subject to an error of at least t 50%. Annual turnover ratios (P/B; B is mean biomass) varied from
9 to 19 and were three to four times higher than published values for similar-sized macroinvertebrates in
the temperate zone (generally < 15°C mean annual habitat temperature). This probably resulted from the
higher average temperatures (17-18°C) at most sites.
Dietary studies of Aquatic insects from two Victorian rivers
Authors: Chessman BC
Published: November 2005

A preliminary assessment of the feeding habits of 127 taxa of pre-imaginal Coleoptera, Diptera, Ephemeroptera,
Plecoptera and Trichoptera from the La Trobe and Tanjil Rivers was made from analyses of digestive tract
contents and observations of captive specimens. Ultrafine (<50 �n) detritus was the dominant material
in gut contents of all five orders, and fine (< 1 mm, > 50 �lm) detritus (mostly leaf and wood fragments),
benthic algae (especially diatoms) and remains of invertebrate prey were also important. Bacteria, fungi and
planktonic algae were present in minor quantities. Many species were shown to be capable of shredding
dead leaves and wood. Dietary diversity was particularly high in the families Elmidae, Chironomidae,
Leptophlebiidae, Gripopterygidae and Leptoceridae.
Nematodes, including a new record of Tobrilus diversipapillatus in Australia, as potential indicators of sewage effluent pollution
Authors: Arthington AH , Yeates GW , Conrick DL
Published: November 2005

Nine nematode taxa were collected during a study of the effects of sewage effluent on benthic macroinvertebrates in Bulimba Creek, Brisbane. The nematode, T. diversipapillatus, previously unknown from Australia, comprised 80% of the collection, and was most abundant at polluted sites with high biological oxygen demand and high levels of total organic carbon. Free-living adult and juvenile Mermithidae made up 15.6% of the collection and were most abundant at sites with low biological oxygen demand. The potential of T. diversipapillatus and Mermithidae to serve as biological indicators of organic enrichment and toxic pollution is discussed in terms of these preliminary findings and literature data.
Light attenuation in a small tropical reservoir (Solomon Dam, North Queensland): seasonal changes and the effects of artificial aeration
Authors: Hawkins PR , Griffiths DJ
Published: November 2005

Seasonal changes in light attenuation are described for a small tropical reservoir (Solomon Dam) at Palm Island, north Queensland, and the attenuation characteristics are compared with those reported for other Australian water bodies. The major components of the water column that affect attenuation of photosynthetically available radiation (PAR) were studied over a 4-year period, including 16 months when the reservoir was artificially aerated. The pattern of light attenuation varied at different times of the year, depending largely on the stratification conditions and on the dominant phytoplankton species. The vertical attenuation coefficient for PAR varied on a seasonal basis, the major peaks being related to periods of high phytoplankton densities. The only time tripton contributed significantly to attenuation of PAR was coincident with the start of artificial aeration. Gilvin concentrations in Solomon Dam were moderately high, especially in the hypolimnion of the strongly stratified reservoir. Artificial aeration moderated the range of seasonal fluctuations in light attenuation, by reducing the density of phytoplankton in the surface layers.
An ecological classification of the burrows of Australian freshwater crayfish
Authors: Horwitz PHJ , Richardson AMM
Published: November 2005

A classification of freshwater crayfish burrows, based on their relationship to the water-table, is presented. Burrows are divided into three classes, the third of which is apparently not found outside Australia and contains burrows which are independent of the water-table, receiving their water from surface run-off. The classification is compared with Hobbs classification of North American crayfish which is based on their burrowing behaviour.
Life histories of some Australian Siphlonurid and Oligoneuriid mayflies (Insecta : Ephemeroptera)
Authors: Campbell IC
Published: November 2005

The life histories of nine populations of mayflies were investigated through monthly field collections over a 3-year period. Seven species were studied, one each from the genera Tasmanophlebia, Ameletoides and Mirawara (Siphlonuridae) and four from Coloburiscoides (Oligoneuriidae). Nymphs were sorted and measured and life histories inferred from size frequency diagrams, and cohorts were separated using a technique for distinguishing multiple overlapping normal distributions. The life histories were all relatively poorly synchronized with adult emergence extended over 5 months or more in every case. A wide size range of nymphs was present in most populations for most of the year and these often formed multiple overlapping cohorts. The time required for development by different cohorts of a single population was quite varied. Marked differences in the length and timing of the adult emergence period, and of the importance of particular cohorts, were apparent in different years. It was concluded that more than a single year's data from one site was necessary to interpret the life histories of Australian mayflies adequately. The four Coloburiscoides species investigated displayed a wide range of development times and patterns, the shortest being displayed by C. haleuticus. This species had some cohorts that seemed to complete their development in about 6 months, whereas C. giganteus had some cohorts that required up to 3 years and also appeared to have a nymphal or early-instar diapause of between 9 and 11 months. The life-history patterns found in this study did not readily fit into the classification schemes proposed by Northern Hemisphere workers. The general asynchrony found in this and previous Australian studies makes it doubtful that a useful classificatory system for Australian mayfly life histories can be developed.
Validation of aging and length back-calculation in rainbow trout, Salmo gairdneri Rich., from Dee Lagoon, Tasmania
Authors: Davies PE , Sloane RD
Published: November 2005

Fin-clipped S. gairdneri yearlings, derived from wild stock, were released into Dee Lagoon, central Tasmania, in 1978 and 1979. A further release of yearlings without fin-clips was made in 1980. Recaptures from 1979 to 1983 allowed validation of scale aging and back-calculation of length from collected scale samples. Back-calculation of size at release, Lr was possible due to formation of a distinct scale check associated with liberation. All back-calculated estimates of Lr and the lengths at the third and fourth winters, L3 and L4, agreed within 5% of actual values. Difficulty in identifying the location of the second winter check initially led to consistent underestimates of L2 but did not affect the accuracy of scale aging. Retention of only precise observations of the second check in the calculations increased the estimate of L2 to agreement with real values. The importance of validation of aging techniques is stressed.
Feeding selectivity of a guild of piscivorous fish in mangrove areas of north-west Australia
Authors: Blaber SJM
Published: November 2005

Piscivorous fish are unusually abundant in mangrove creeks in the Dampier region of north-west Australia
(20°40′S.,1 16°40′E.). Penetration of mangroves by predators is relevant to the role of such waters as nursery
grounds. Caranx ignobilis, Carcharhinus limbatus, Scomberoides commersonianus and Scornberomorus
semifasciatus were the most numerous predators. More than 50% of suitably sized potential prey fish
species were consumed; the most common prey were Atherinidae, Gobiidae, Ambassis sp. and Sillago
spp. Small (1-9 cm), permanently resident species constituted 60% of prey, and juveniles of larger species
made up the balance. Feeding selectivity was assessed on three electivity indices and caution in their use
is emphasised. Although the results conflicted, only the linear index could be statistically tested and two
interesting points emerged. Firstly, of the three most common prey species, two were positively selected
and one negatively selected, and the remainder were consumed in approximate proportion to their
abundances. Secondly, the indices gave similar rank order preferences, with Atherinidae, Sillago spp.
and Harengula sp. the most preferred and Ambassis sp. the least preferred.
Genetic subdivison of stocks of Snapper, Chrysophrys unicolor, in Shark Bay, Western Australia
Authors: Johnson MS , Creagh S , Moran M
Published: November 2005

Variation of allozymes in C. unicolor from Shark Bay was examined as a test for subdivision of the stocks. Samples from the three major areas of the bay (outer bay, and eastern and western gulfs) were genetically differentiated from each other, showing different allelic frequencies at three of the four polymorphic loci studied. The observed genetic differences support the view that snapper from different areas of Shark Bay represent separate breeding populations.
Karyology of the Indo-Pacific Parioglossus raoi (Herre) (Teleosstei : Gobioidei) from Fiji
Authors: Webb CJ
Published: November 2005

The diploid number of chromosomes from gills, spleen and gonads of Fijian specimens of P. raoi was 46, 23 bivalents being observed during the meiotic division in spermatocytes. The karyotype comprised 23 pairs of telocentric chromosomes, giving an arm number of 46. There was no evidence for morphologically identifiable sex chromosomes. Comparisons with other gobioids indicate that the karyotype of P. raoi is superficially similar to those of a number of taxonomically diverse members of the suborder and bears no special resemblance to species from a similar ecotope.
Different reproductive strategies in a sex-changing coral reef fish Centropyge bicolor (Pomacanthidae)
Authors: Aldenhoven JM
Published: November 2005

A model is developed which evaluates the reproductive advantage of staying female or changing sex and becoming a male, using field data for the angelfish C. bicolor. Changing sex can lead immediately to taking over a territory and mating with a harem, or it may involve a period of time as a bachelor which waits for a territory vacancy. Bachelor males carry an initial cost of little or no reproduction but on the death of a dominant male have a better chance than females of acquiring territories and haremmating success. The model predicts that to be a bachelor is better than to stay female up to a certain density of bachelors. The predicted frequency of bachelors agrees with their natural density in the area in which they occur. The model also predicts that under some conditions there will be no advantage in becoming a bachelor; this agrees with observations at three study sites.
Impact of the 1983 wildfires on river water quality in East Gippsland, Victoria
Authors: Chessman BC
Published: November 2005

Eleven stream stations within the basins of the Bemm, Cann, Thurra, Wingan and Genoa Rivers were sampled during a 3-month interval following a prolonged drought and intense and extensive forest fires. Emphasis was placed on flows resulting from three major storms that occurred during this period. Water-quality impacts of the fires were intermingled with those of the preceding drought, and flow- related comparisons with pre-drought data showed appreciable increases in colour, turbidity, suspended solids, potassium and nitrogen levels in the Bemm River, which was only marginally affected by the fires. In the Cann and Genoa Rivers, with much larger proportions of catchment burnt, electrical conductivity and phosphorus concentrations also rose substantially. Marked depletion of dissolved oxygen (to <6 mg I-1) was unique to streams with burnt catchments, but resulted from stagnant conditions at the end of the drought as well as from changes occurring at the time of the first post-fire storm. The fires had little obvious effect on temperature and pH regimes. Peak turbidities and concentrations of suspended solids and phosphorus were much greater in the Cann and Genoa river systems than elsewhere. Maximum values for these indicators were 130 NTU, 2300 mg I-1 and over 0.8 mg I-1, respectively. In the Thurra and Wingan basins, which were also burnt, stream suspended-solids levels were lower (<200 mg I-1), but solutes sometimes reached very high maxima (indicated by peak electrical conductivities of up to 110 mS m-1). Variations in catchment topography and soils and the relative importance of surface and subsurface flow probably account for these differences. The first post-fire storm produced the highest measured levels of many indicators in most streams, although the greatest flows were associated with the third storm. Nitrite and ammonia were notable exceptions to this generalization. Estimates of catchment exports indicated high sediment yields and moderate to high phosphorus yields from the Cann and Genoa catchments, by comparison with other Australian data.
Copper-complexing capacity of South Pacific waters
Authors: Mackey DJ
Published: November 2005

The strong copper-complexing capacity of seawater from the western tropical Pacific Ocean and the Coral Sea has been measured by a method based on competition between naturally occurring ligands and Chelex-100 ion-exchange resin. In the nutrient-depleted surface waters, the values ranged from 4 to 72 nM. For deeper waters there were larger variations with values ranging from 2 to 136 nM in the region of the salinity minimum at approximately 800-1000 m. There was no evidence for increased complexing capacity due to the sediment-water interface. Since changes in complexing capacity are ultimately of biological origin, the variability must have arisen when the waters were in the euphotic zone at polar latitudes. The samples were unfiltered and the complexing capacity could be due to either dissolved organic compounds or to particles so small that their settling velocities are negligible compared with the time elapsed since the water parcel was last in the euphotic zone. There is no direct correlation between complexing capacity and water density or concentration of nutrients. The results suggest that parcels of water up to 100 km wide can travel distances up to 10 000 km and maintain a chemical signature different from the surrounding water.
Spawning stock-recruitment relationships and environmental influences on the tiger prawn (Penaeus esculentus) fishery in Exmouth Gulf, Western Australia
Authors: Penn JW , Caputi N
Published: November 2005

A stock-recruitment relationship (SRR) between the spring spawning stock levels and the following autumn recruitment has been established for P. esculentus in Exmouth Gulf. The basic SRR fits the data well with the exception of 2 out of the 14 years when particularly severe cyclones occurred. This has been taken into account by using multiple regression techniques to incorporate the amount of rainfall in January and February as variables representing indices of cyclone activity (multiple correlation of 0.97). An hypothesis for the observed positive and negative effects of cyclones on recruit survival has been presented. The relationship between autumn recruitment and resultant spring spawning stock (RSR) later that year and the effects of fishing, measured in effective effort units, has also been established (multiple correlation of 0.94). An examination of the interaction between the SRR and RSR relationships has been reported which suggests that, under average environmental conditions and high levels of effort, recruitment will move towards a new lower equilibrium level. The robustness of the relationships with respect to assumptions involved and potential sources of bias in the variables used have been evaluated and discussed.
Effects of wind and tide on upper-layer currents at Davies Reef, Great Barrier Reef, during MECOR (July-August 1984)
Authors: Pickard GL
Published: November 2005

At Davies Reef, flow over the east reef flat was unidirectional downwind at 10-20 cm s-1 with strong winds and smaller tides but was semi-diurnal tidal reversing at 5-15 cm s-1 with lighter winds and higher tides. The flood direction was to the south-east out of the lagoon and the ebb into the lagoon. Wave overtopping was estimated to contribute at least 40% of the flow over the reef flat-the first estimate of this component of flow over reef flats. Transit times over the reef flat were 30-170 min and flushing times for the east lagoon were estimated as ½ -1 day for strong winds to the north-west but 2-4 days for lighter winds. In the east lagoon, the upper-layer currents were semi-diurnal tidal reversing all the time at speeds up to 20 cm s-1, with longer-term net flow downwind at about 2 cm s-1 with strong winds but upwind at 0.2 cm s-1 with light winds. In the east passage, the strongly tidal currents (up to 60 cm s-1.) had a long-term net flow to the south at about 2 cm s-1 without any clear correlation with the wind.
Distribution of cadmium, lead and zinc amongst the marine sediments, seagrasses and fauna, and the selection of sentinel accumulators, near a lead smelter in South Australia
Authors: Ward TJ , Correll RL , Anderson RB
Published: November 2005

The concentrations of Cd, Pb and Zn in 23 species of marine animal and three species of seagrass were determined from samples collected near a large lead smelter. The spatial patterns of metal distribution in sediments, seagrasses, crustaceans and fish could be described in terms of distance from the smelter, although the fit of the mathematical model was often improved by the inclusion of other environmental variables, such as clay content of the sediment or time of sample collection. In the fish and seagrasses, Zn was the most widely dispersed metal, followed by Cd, then Pb, which was least dispersed. In general, organisms at higher trophic levels (fish) had lower metal concentrations than primary producers (seagrass). There was evidence for bioaccumulation of metals in many species, especially in the molluscs, but no biomagnification of any metal could be detected. The strong relationship between distance and metal content of several species of seagrass, fish and crustacean indicates that they are potential sentinel accumulators for monitoring the distribution of Cd, Pb and Zn. Although bivalve molluscs contained high concentrations of Cd, Pb and Zn, their contents did not consistently relate to distance from the smelter, suggesting that, except for Pinna bicolor, they are of little value as sentinel accumulators for these metals. The implications of the results for the design of monitoring programs using sentinel accumulators are discussed.
Haemosiderosis in Platycephalus bassensis and Diodon nicthemerus in south-east Australian coastal waters
Authors: Langdon JS
Published: November 2005

The degree of haemosiderin deposition in the spleen, liver, and kidney of P. bassensis and D. nicthemerus was compared in specimens from Port Phillip Bay, and Lakes Entrance, Victoria, Bass Strait, and the Derwent estuary, Tasmania. D. nicthemerus displayed extensive visceral haemosiderosis and fatty infiltration of the liver at all sites, apparently as normal conditions. P. bassensis from Port Phillip Bay displayed severe visceral haemosiderosis, whereas specimens from the remaining sites had only low background levels of haemosiderin deposition. It is suggested that high levels of visceral haemosiderin in fish species normally displaying low levels are indicative of a suboptimal health status in fish populations. No infectious cause of the haemosiderosis in Port Phillip Bay fish has been identified, and toxic or pollution-related causes are thus considered likely to be responsible.
Descriptions of the nisto stage of Scyllarus demani Holthuis, two unidentified Scyllarus species, and the juvenile of Scyllarus martensii Pfeffer (Crustacea : Decapoda : Scyllaridae), reared in the laboratory; and behavioural observations of the nistos of S. demani, S. martensii and Thenus orientalis (Lund)
Authors: Barnett BM , Hartwick RF , Milward NE
Published: November 2005

Live final-stage phyllosoma larvae of T. orientalis, S. martensii, S. demani, and an unidentified specimen,
Scyllarus sp. A, were obtained from the mid-shelf region of the Great Barrier Reef. While held in the
laboratory, larvae of all species metamorphosed to the subsequent, nisto, stage; the nisto of S. martensii
developed further to the first juvenile phase. An additional, nisto, Scyllarus sp. B, obtained in a plankton
sample, remains unidentified. In this paper, the nistos of S. demani, Scyllarus sp. A, and Scyllarus
sp. B, and the juvenile of S. martensii are described; and behavioural observations of live material, including
nistos of T. orientalis, are discussed.
Population structure and trophic composition of the free-living nematodes inhabiting carbonate sands of Davies Reef, Great Barrier Reef, Australia
Authors: Alongi DM
Published: November 2005

Population structure and trophic composition of free-living nematodes from carbonate sands within different functional zones (reef crest, reef flat and lagoon) of Davies Reef in the Great Barrier Reef were examined. At the reef crest (station C) and at a shallow lagoon area unprotected by the back wall of the reef flat (station G), sediments were subjected to intense wave action and supported significantly (P < 0.05) lower mean nematode densities (<60 individuals per 10 cm2) than sands within the other reef zones (100-400 individuals per 10 cm2). Mean nematode densities and numerical species richness were highest (P < 0.05) in a shallow lagoon habitat protected from hydrodynamic- induced disturbances by the back wall of the reef flat (station H). Differences in population densities among the reef zones were not related to water depth or sediment granulometry. Species diversity was low within the reef, with only six species present in deep lagoon sands co-inhabited by actively bioturbating ghost shrimps (Callianassa spp.). Normal classification, nodal analysis and detrended correspondence analysis indicated that faunal groups were distinct among the different reefal zones. Very coarse to medium sands at the reef crest and across the reef flat were inhabited primarily by omnivorous and epistrate-feeding nematodes. Most nematodes within the very fine to fine sands of the lagoon were non-selective or selective deposit feeders. Nematode community structure from the reef crest to the shallow lagoon appears to be determined primarily by sediment granulometry as controlled by reef hydrodynamics, whereas in the deep lagoon nematode communities are negatively affected by the presence of thalassinid ghost shrimps.
Feeding ecology of Macruronus novaezelandiae (Hector) (Teleostei : Merlucciidae) in south-eastern Australia
Authors: Bulman CM , Blaber SJM
Published: November 2005

The diet and feeding ecology of the demersal merlucciid M. novaezelandiae from three areas of the upper continental slope (420-550 m) of south-eastern Australia are described. The food consists almost entirely of mesopelagic fauna. The major prey are myctophid fish Lampanyctodes hectoris, other fishes, natant decapods, euphausiids and squid. Energy values of major prey items were determined by bomb calorimetry. Although euphausiids occur frequently in the diet, fish make up 90% of the energy intake. There is little regional variation. M. novaezelandiae undertakes diel vertical migrations that are similar to those of its prey, bringing it within 50 m of the surface at night. There is a seasonal trend towards cannibalism by adults on juveniles.
Biology of two commercially important carcharhinid sharks from northern Australia
Authors: Stevens JD , Wiley PD
Published: November 2005

Sharks represent 78% of the total catch by weight of a Taiwanese surface gill-net fishery off northern
Australia. Two carcharhinids, Carcharhrnus tilstoni (previously described as C. limbatus) and C. sorrah,
together comprise 83% of this shark catch by number. C. tilstoni is distinguished from C. limbatus by
differences in enzyme systems, vertebral counts, size data and pelvic fin coloration. Of the specimens
of C. tilstoni and C. sorrah caught in the Arafura and Timor Seas from 1981 to 1983, 43% and 47%,
respectively, were female; at birth these proportions were 46% and 50%, respectively. In both species,
females tended to be relatively more abundant in catches of mature fish, except around March, when
males predominated. In northern Australia, the usual size at maturity for C. tilstoni is 110 cm for males
and 115 cm for females; for C. sorrah, it is 90 cm and 95 cm, respectively. Both species exhibit placental
viviparity and have almost identical restricted reproductive cycles. Mating occurs in February-March,
ovulation in March-April and the main parturition period is in January. The gestation period is 10 months
and individual fish breed each year. The average litter size for both species is three. The size at birth
is about 60 cm for C. tilstoni and 50 cm for C. sorrah. Stomach contents indicate that teleost fish are
an important component of the diet of both species and there is some indication of a change in feeding
depth with shark size.
Gill net mesh selectivities for gummy shark, Mustelus antarcticus Günther, taken in south-eastern Australian Waters
Authors: Kirkwood GP , Walker TI
Published: November 2005

Experiments designed to estimate length-specific selectivities for gill nets used to catch gummy shark, M. antarcticus, were carried out in south-eastern Australian waters between 1973 and 1976. Eight nets were used, with mesh sizes ranging from 5.08 to 22.78 cm (2-9 in.) in steps of 2.54 cm (1 in.). Existing methods for estimating mesh selectivities are reviewed, and an alternative method, which overcomes some problems in the existing methods, is described. In this method, an assumed selectivity function is fitted directly to catch data for a number of different mesh sizes, with the parameters of the selectivity function being estimated simultaneously across mesh sizes and length-classes. The new method is used to estimate selectivities for the gummy shark data, on the assumption that the selectivity function takes the shape of a gamma distribution. Data from the 2- and 3-in. mesh nets did not satisfy the assumptions of the procedure, but estimates of mesh selectivities were successfully obtained for the 4-9-in. mesh nets.
Effects of 0.2mm membrane-filtered seawater as a culture medium on fertilized eggs and larvae of the pacific oyster, Crassostrea gigas
Authors: Garland CD , Cooke SL , McMeekin TA , Valentine JE
Published: November 2005

Early stages of C. gigas were reared in the laboratory at 25.5� C in 500-ml culture vessels devised to exclude contaminating microorganisms, and were fed axenic microalgae. Raw seawater or 0.2-�m membrane- filtered (m-f) seawater was used as the culture medium, changed at 2-day intervals. Eggs fertilized in raw seawater transformed at normal rates into trochophore and D-shape larvae when suspended in m-f seawater. However, the use of m-f seawater in larval culture was counterproductive in controlling bacterial populations. Compared to animals reared successfully in raw seawater, D-shape larvae failed to develop normally in m-f seawater. The animals grew minimally, exhibited shell and velum abnormality, and most were dead by 9 days of age. During the 2-day periods, total bacterial levels (loglo units) increased from < 1 to >6 ml-1 in m-f seawater, but from 3.95 to < 6 ml-1 in raw seawater. Fatal disease of oyster larvae was due to mixed bacterial populations rather than to Vibrio strains.
Ecology of humic and non-humic dune lakes, Fraser Island, with emphasis on the effects of sand infilling in Lake Wabby
Authors: Arthington AH , Burton HB , Williams RW , Outridge PM
Published: November 2005

Aspects of physicochemical limnology and the zooplankton, littoral invertebrates and fish of dune lakes on Fraser Island are described and compared. The comparisons highlight differences between perched, humic lakes and the non-humic Lake Wabby, a water-table window with some morphometric and biological features typical of dune barrage lakes. Lake Wabby has been partially infilled by a mobile sand dune moving mainly in a north-westerly direction across the northern end of the lake. The maximum rate of dune advance estimated from aerial photos was 5.03 m year-1, between 1948 and 1958. Sand infilling between 1975 and 1984 altered the morphometry and substrate characteristics of the lake's eastern region and reduced maximum depth from 13.0 to 11.5 m and volume by 43%. The number of benthic invertebrates was reduced from 14 taxa in 1975 to six taxa in 1984; there was also a significant decrease in abundance of benthic Chironomini during this period (ANOVA, P < 0.05). In both years, an undescribed species of Conochironomus was the most abundant benthic invertebrate in Lake Wabby (250-700 individuals m-2). A new genus of Chironomini (near Paralauter borniella) was discovered. Lake Wabby supported 11 species of fish in 1975 and 1984, but the perched lakes had only one or two species. The five most abundant species in Lake Wabby in 1975 showed evidence of partitioning of food resources, of which the main components were benthic invertebrates and filamentous algae. Allochthonous food resources were not important in fish diets. The possible long-term effects of sand infilling on food resources, fish diets and the composition of the zooplankton in Lake Wabby are discussed.
Rotifera from Australian inland waters. I. Bdelloidea (Rotifera : Digononta)
Authors: Koste W , Shiel RJ
Published: November 2005

In this paper, the first of a series providing a systematic revision of all Rotifera now known from Australian inland waters, the common bdelloid rotifers are reviewed. The group is epiphytic or epibenthic in habit, but some species commonly occur in open water of billabongs, lakes and rivers, particularly in association with algal blooms. Frequent occurrence of bdelloids in plankton collections necessitates diagnostic keys to their identification. For the common species only, morphological features of taxonomic significance are described and figured to facilitate further study.
Comparative recruitment of the banana prawn, Penaeus merguiensis, in five estuaries of the south-eastern Gulf of Carpentaria, Australia
Authors: Staples DJ , Vance DJ
Published: November 2005

Recruitment patterns of postlarvae immigrating into mangrove nursery areas of five major estuaries around the south-eastern Gulf of Carpentaria, as well as juveniles emigrating offshore into coastal waters, were compared for the banana prawn, Penaeus merguiensis, from September 1978 to March 1979.. Although considerable variability was observed among rivers, some basic recruitment patterns were discernible. Recruitment of postlarvae tended to follow a 28-day cycle with increased immigration on alternate spring tides. Variability between rivers in the number of resident juvenile prawns at any one sampling time resulted mainly from differences in the relative magnitude of postlarval settlement from these monthly cohorts. After the first heavy rainfall of the monsoon season, the lower reaches of rivers with !xger catchment areas a!! ran fresh, setthg up a physica! barrier to further past larval immigration. In contrast, post larval immigration continued throughout the study period in the river with the smallest catchment. There was a trend for more successful immigration earlier in the more northern rivers. Offshore emigration was influenced by rainfall, tide height and number of resident juvenile prawns at the time of emigration. The relative importance of these three factors differed among rivers, depending on the timing of rainfall in relation to the timing of juvenile population changes and the degree of flooding. These local differences in the timing of emigration of juveniles could be detected in the abundance and size of adolescent prawns in the offshore coastal area of the south-eastern Gulf which in turn influenced the size composition of prawns available to the commercial fishery.
A study of the species composition and distribution of commercial penaeid prawns of Torres Strait
Authors: Somers IF , Poiner IR , Harris AN
Published: November 2005

Fishermen's logbook data were used to describe the distribution of fishing effort and the composition of the commercial catches in Torres Strait. Catches consist of tiger, endeavour and king prawns. Additional information on the distribution and abundance of the individual species was obtained from four trawl surveys carried out at 3-monthly intervals during 1985. Each survey extended over the entire area of the commercial prawn fishery in Torres Strait. The species composition of the trawl surveys (48% tiger, 44% endeavour and 8% king) differed noticeably from that of the commercial catch (60% tiger, 36% endeavour, 4% king). This difference was attributed to a combination of the commercial fishery's concentration on the higher-priced tiger prawns and the different spatial and temporal distributions of the species. The tiger prawn catch consisted of two species, Penaeus esculentus (99.6%) and P. semisulcatus (0.4%). The king prawn catch comprised P. longistylus (97.5%) and P. latisulcatus (2.5%). The endeavour prawn catch was represented by a single species, Metapenaeus endeavouri. Spatial differences in the species distributions were found to be associated with the distribution of bottom sediments. Tiger prawns were most abundant on fine sediments with a mud content greater than 50%; P. semisulcatus was restricted to sediments with a mud content greater than 70%. The king prawns, unlike the tiger prawns, were most abundant on the coarse sediments with a mud content less than 20%. Endeavour prawns were the most widespread of all the species, being equally abundant on all sediment types.
Distribution and abundance of the tiger prawns Penaeus esculentus and P. semisulcatus in the north-western Gulf of Carpentaria, Australia
Authors: Somers IF , Crocos PJ , Hill BJ
Published: November 2005

Trawl surveys in the north-western Gulf of Carpentaria were carried out each lunar month from August 1983 to March 1985 to assess the temporal and spatial distribution and abundance of P. esculentus and P. semisulcatus. The information obtained was then compared with that from fishermen's logbooks. Water temperature and salinity were monitored during the study and their possible influence on the distributions has been inferred. The distributions of juveniles of less than 20 mm carapace length indicated that, for both tiger prawn species, the main nursery areas in the region were in Blue Mud Bay and in the bays along the northern coast of Groote Eylandt. Although the two species shared the same nursery areas, the juveniles were concentrated in different parts of Blue Mud Bay and were most abundant at different times. Catches of juvenile P. esculentus increased substantially in October and peaked in November, whereas catches of juvenile P. semisulcatus increased in November and peaked in January. Catches of both species showed a secondary peak in March 1984, coincident with the heaviest monthly rainfall of the summer monsoon season. The distribution of larger prawns showed spatial separation of the two species in the offshore fishery. The monthly pattern of the catch-per-unit-effort (CPUE) of the two tiger prawn species combined was similar to that obtained from fishermen's logbooks; the logbook data are therefore generally reliable. Monthly CPUE from the trawl surveys for the individual species showed distinct peaks in late summer, which were apparently related to recruitment of small prawns into the fishery. CPUE for P. semisulcatus peaked in February and April (juvenile abundance had peaked in January and March); CPUE for P. esculentus peaked in January and May (juvenile abundance had peaked in November and March). However, a distinct CPUE peak in spring (August/September) for P. semisulcatus could not be related to a previous peak in juvenile abundance; this was presumably a result of an increase in catchability. Although there was evidence linking changes in the catchability of P. semisulcatus to changes in water temperature, a similar link was not as evident for P. esculentus.
Reproductive dynamics of the grooved tiger prawn, Penaeus semisulcatus, in the north-western Gulf of Carpentaria, Australia
Authors: Crocos PJ
Published: November 2005

The reproductive cycle of female P. semisulcatus was investigated in the region north of Groote Eylandt in the Gulf of Carpentaria from August 1983 to March 1985. Approximately 1750 trawls were carried out over 21 monthly sampling cruises, and 13 748 females were examined. The minimum size at maturity was 29 mm carapace length (CL), and 50% of the population were mature at 39 mm CL. The proportion of females which had mated increased sharply above 34 mm CL with a maximum of 80% of females inseminated in the size range 38-54 mm CL. An index of population egg production, calculated from female abundance, the proportion of females spawning and fecundity according to size, was used as an indicator of reproductive output. Egg production was markedly seasonal, with a major spawning peak in August-September, and a minor one in February. Spawning occurred in a limited area within rhe study area. The spawning stock of P. semisulcatus is likely to be vulnerable to fishing pressure because the area and time of major spawning coincides with the major fishing effort in the region.
Reproductive dynamics of the tiger prawn Penaeus esculentus, and a comparison with P. semisulcatus, in the north-western Gulf of Carpentaria, Australia
Authors: Crocos PJ
Published: November 2005

The reproductive cycle of female P. esculentus was investigated in the Groote Eylandt region of the Gulf of Carpentaria from August 1983 to March 1985. The minimum size at maturity for P. esculentus was 25 mm carapace length (CL), and 50% of the population were mature at 32 mm CL. The proportion of females which had mated increased sharply above 28 mm CL to a maximum of 80% inseminated in the size range 32-50 mm CL. An index of population egg production, calculated from female abundance, the proportion of females spawning and fecundity with size, was used as an indicator of reproductive output. Egg production tended to be spread throughout the year, but with eggs being produced most consistently in late winter and early spring. Spawning occurred in a limited area within the study area. A comparison of P. esculentus and P. semisulcatus showed that P. esculentus matures at a smaller size (50% at 32 mm CL) than P. semisulcatus (50% at 39 mm CL), fecundity is lower, spawning is nearer inshore and egg production is less strongly seasonal.
Distribution of seagrasses and associated juvenile commercial penaeid prawns in north-eastern Queensland waters
Authors: Coles RG , Lee Long WJ , Squire BA , Squire LC , Bibby JM
Published: November 2005

Thirteen species of seagrass and six species of juvenile penaeid prawn of commercial importance were found in seagrass beds in waters between Cape York and Cairns. The pioneering seagrass species, Halodule uninemis (Forsk.) Aschers, and Halophila ovalis (R. Br.) Hook. f., were present in almost all coastal areas. Two seagrass species often dominant in the tropics, Enhalus acoroides (L.f.) Royle and Thalassia hemprichii (Ehrenb.) Aschers., were uncommon. This is likely to have resulted from environmental stress during periods of reduced salinity and high turbidity associated with seasonal summer rainfall. Halophila decipiens Ostenfeld was the only species found in depths > 11 m. Three depth-related zones of species are described. With the exception of E. aroroides, most seagrasses were <20 cm in height. Seagrass biomass was greatest in 2-6 m of water. Maximum dry weight of above-ground plant material and maximum leaf area from a square metre of bottom was 99.6 g and 4.5 m2, respectively, at the Flinders Group of islands. The distribution of prawns and seagrasses did not show a trend with latitude. Penaeus esculentus Haswell and Metapenaeus endeavouri (Schmitt), the most numerous penaeid prawn species in commercial trawl catches, were also the most numerous juvenile prawns in seagrass beds. Juvenile P. longistylus Kubo were found for the first time in northern Queensland seagrass beds. Although juveniles of this species appeared to occupy only a narrow habitat range, these habitats were found in coastal bays, in estuaries and on coral-reef platforms where conditions were suitable. Size-class data suggest that reef prawns and coastal prawns are parts of the same population. The timing of the life cycle of the major commercial prawn species differed from that found previously in the Gulf of Carpentaria.
Surficial sediments of the western Gulf of Carpentaria, Australia
Authors: Jones MR
Published: November 2005

Modern sedimentation in the Gulf of Carpentaria is confined principally to marginal areas in water depths of less than 50 m. Within this zone, the distribution of sediments is irregular, being controlled by proximity to sediment sources and degree of exposure to waves and tidal activity. This is particularly so in the western gulf, where fluvial sediments supplied to Limmen Bight have been transported by waves and tides northwards beyond that embayment to accumulate in the sheltered environment of Blue Mud Bay. Limmen Bight is exposed to the south-easterlies, which produce sufficient wave action in the nearshore zone to prevent the widespread deposition of fine-grained terrigenous sediments. As a result, relict sand deposits occupy much of the floor of Limmen Bight in areas shallower than about 25 m. In deeper areas, terrigenous muds are deposited at a low rate over relict fluvial and marine sediments. The relict deposits accumulated in continental and nearshore marine environments during low-sea-level periods of the late Pleistocene.
Natural diet of the tiger prawns Penaeus esculentus and P. semisulcatus
Authors: Wassenberg TJ , Hill BJ
Published: November 2005

Foregut contents of 702 P. esculentus and 426 P. semisulcatus collected from seagrass and offshore habitats in the Gulf of Carpentaria, Torres Strait and Moreton Bay between December 1983 and March 1984 were analysed, and the numerical composition and frequency of occurrence of food items in the diet were compared statistically. Periodicity in feeding was examined in adult prawns collected in hourly 20-min trawls overnight. Gut contents from these prawns were weighed and corrected for size by an empirically derived relationship V = 0.00931l2.818 between gut volume (V, �l) and carapace length (I, mm). The guts of both species were partially filled with food throughout the night. Bivalves, gastropods, ophiuroids, crustaceans and polychaetes were the most abundant food items of both species. Dietary composition overlapped for both species caught in the same trawl, but significant differences (P<0.05) were found in average numbers of pariicuiar items. No significani differences (P > 0.05) in numerical composition or frequency of occurrence of dietary items were found between the sexes of either species. Bivalves, gastropods and crustaceans were the most common items in juvenile and adult P. semisulcatus. Bivalves and gastropods were the most common food items in juvenile and adult P. esculentus. Bivalves were more common in adult than in juvenile P. esculentus. Ophiuroids were found more frequently with larger size of P. esculentus but were constant in all sizes of P. semisulcatus. The only meiofauna found in either species in significant numbers were harpacticoid copepods and these were found mainly in prawns from seagrass beds. P. esculentus and P. semisulcatus appear to eat similar taxa of benthic fauna. Quantitative differences between the diets of both species of prawns captured in the same trawl suggest that they are selective in their diet. Strong regional differences in diet were probably due to differences in the availability of prey.
Feeding behaviour of adult tiger prawns, Penaeus esculentus, under laboratory conditions
Authors: Hill BJ , Wassenberg TJ
Published: November 2005

Adult tiger prawns, P. esculentus, when offered a choice of food, showed significant preferences. They preferred feeding on tissue from the prawn Metapenaeus bennettae to tissue from the bivalve Perna canaliculus but preferred P. canaliculus to the prawn Penaeus longistylus. When given a choice of two bivalves, they preferred Donax deltoides to Perna canaliculus. Prawns preferred fresh food to food that had been soaked for several hours. If food was given only at dusk, feeding occurred mainly in the first half of the night. If additional fresh food was given at midnight, then an equal amount of feeding occurred after midnight. The prawns spent short periods (mean 9.3 min) at the food. These were separated by non-feeding intervals with a mean length of 42 min. This behaviour was repeated about six times each night. Tiger prawns filled their foreguts to about 60% of capacity within 10 min of beginning feeding and could clear about 50% of the content in 30 min and nearly 55% in 60 min. Females and males spent the same amount of time feeding. When starved, P. esculentus emerged from the substrate for longer periods at night, moved around more, and emerged during the day.
Movements and breeding of the ornate rock lobster, Panulirus ornatus, in Torres Strait and on the north-east coast of Queensland
Authors: Bell RS , Channells PW , MacFarlane JW , Moore R , Phillips BF
Published: November 2005

The principal biological question examined by the investigation was whether the resource of P. ornatus fished in Papua New Guinean waters was the same as that fished in Australian waters. In all, 11 932 specimens of Panulirus ornatus were tagged in Torres Strait and on the north-east coast of Queensland over a 3-year period from February 1980 to March 1983. By June 1984, 300 tagged P. ornatus had been recaptured. Of the 9632 P. ornatus tagged on the east coast of Queensland, none was recaptured in Torres Strait, while most of the 24 recaptures showing movements occurred to the south of the tagging sites. Of the 2300 P. ornatus tagged in Torres Strait, 8 were recaptured at sites to the north-east of the tagging sites in September and October 1980, coincident with the annual breeding emigration of P. ornatus from reefs in Papua New Guinean waters in northern Torres Strait, across the Gulf of Papua to breeding grounds near Yule Island. Results of this tagging study showed that P. ornatus from western Torres Strait also emigrate into Papuan New Guinean waters, where they are fished by both Australian and Papua New Guinean fishermen. However, recapture data also indicated that the population of P. ornatus in south-east Torres Strait and on the east coast of Queensland does not take part in this breeding emigration and may be a separate resource. During the study, 39 berried female P. ornatus were found on the north-east coast of Queensland but none in Torres Strait. The breeding stock near Yule Island may be the source of recruitment to both the Torres Strait and north-east coastal Queensland fisheries.