bluuebunny/crossref_metadata_2025 huggingface dataset:
Natural hybridization between Murray cod, Maccullochella peelii peelii (Mitchell) and trout cod, Maccullochella macquariensis (Cuvier) (Percichthyidae) in the Murray River, Australia
Authors: Douglas JW , Gooley GJ , Ingram BA , Murray ND , Brown LD
Published: November 2005

Hybridization is confirmed between two wild, naturally sympatric populations of Murray cod, Maccullochella peelii peelii, and trout cod, M. macquariensis, from the Murray River, Australia. Electrophoretic comparisons of proteins in muscle and liver tissues from trout cod, Murray cod, an artificially produced hybrid of Murray cod and trout cod, and putative wild hybrids from the Murray River indicated that the last group were first-generation interspecific hybrids. This is the first record of hybridization between naturally occumng populations of these two species. Naturally occurring wild populations of both trout cod and Murray cod are nonetheless genetically distinct and there is no evidence of introgression between the species. These findings have some implications for management policies and practices in relation to both species, and these are discussed.
Reproduction of the sea urchins Echinometra mathaei and Diadema savignyi on the South African eastern coast
Authors: Drummond AE
Published: November 2005

The reproductive cycles of Echinometra mathaei and Diadema savignyi on the South African eastern coast were investigated by means of gonad index and histological methods. Both species showed annual cycles, with spawning occurring during the summer months (December to March-April), but the degree of gametogenic synchrony differed markedly between the two species. In D. savignyi, gametogenesis within and between sexes was in close synchrony and there was evidence suggesting that repeated spawning with a monthly rhythm occurred. In contrast, gametogenesis in E. mathaei was poorly synchronized and spawning occurred over an extended period.
Aerial survey of the dugong (Dugong dugon Muller 1776) in coastal waters of the Lease Islands, East Inodonesia
Authors: de Iongh HH , Wenno R , Bierhuizen B , van Orden B
Published: November 2005

During December 1990 and August 1992, aerial surveys of dugongs were made along the coastlines of the Lease Islands in East Indonesia. The aerial surveys followed a strip transect covering the coastal shelf and totalled 3.5 h of observation. During the first survey, 17 dugongs were observed, one of which was a neonatal calf; during the second survey, 10 dugongs were seen but no neonates. The minimum population of dugongs was estimated to be between 22 and 37 animals. The population probably interacts with a larger unidentified reservoir of dugongs in the coastal waters of nearby Seram and Buru Islands.
Topographic influence on the pattern of flow through Bass Strait
Authors: Baines PG , Murray DL
Published: November 2005

A laboratory simulation of the flow through Bass Strait has been made with the aid of a physical model of the topography, situated in a tank on a rotating turntable. The throughflow was driven by a continuous supply of homogeneous water to the western end that was uniform with latitude. The effect of the depth variations within the strait were realistically represented and had a controlling influence on the flow pattern. In particular, the uniform inflow from the west was directed towards the south-eastern region, guided along contours of constant depth around the central depression by approximate conservation of potential vorticity. West of Flinders Island, the flow then splits into a northward branch that flows toward the Victorian coast and leaves the strait near Gabo Island and a southern branch that leaves through Banks Strait. This modelled flow pattern is generally consistent with the outflows inferred from observed temperature and salinity fields.
Geographic variation in the reproductive cycle of the saucer scallop, Amusium balloti, (Bernardi, 1861) (Mollusca:Pectinidae), along the Western Australian coast
Authors: Joll LM , Caputi N
Published: November 2005

The reproductive cycle of the saucer scallop Amusium balloti was examined at three sites spanning a large part of the north-south range of the species on the western coast of Western Australia. Variations in gonad dry weight were highly cyclical, with minimum gonad weights in Shark Bay (25�S) occurring between January and March and maximum gonad weights occurring around July or August. The pattern of variation in gonad weight at the Abrolhos Islands (29�S) and Fremantle (32�S) was similarly cyclical, but the times of high and low gonad weights occurred at similar times at both sites and approximately two months later than in Shark Bay. The variations in gonad weight were associated with large variations in meat weight and condition, which would need to be considered in any yield analyses of fisheries for this species. Gonad dry weight increased rapidly following the end of the resting period, and histological examination showed that gonads contained mature gametes within one to two months of the end of the resting period. Although gonad weights continued generally to increase over a period of three to four months following the end of the resting period, variations in gonad weight during this period indicated that partial spawning may be occurring before the time of peak gonad weight. Residual gametes were observed in the ciliated ducts of scallop gonads within one to two months of the start of the rapid increase in gonad weight until the onset of the resting period, indicating that partial spawning was occurring throughout this time. Estimation of the settlement dates of recruits supported the conclusion that spawning commenced shortly after gonads began their rapid weight increase and suggested that spawning may follow a lunar cycle. Partial spawning provides multiple opportunities for larvae to develop in environments conducive to high larval survival and may be an important factor in determining recruitment success.
Deterministic compartmental model for the eastern king prawn (Penaeus plebejus) fishery in New South Wales
Authors: Gordon GNG , Andrew NL , Montgomery SS
Published: November 2005

Eastern king prawns (Penaeus plebejus) migrate north from estuaries along the eastern coast of New South Wales and are subject to fishing during this migration. A constant-parameter deterministic compartmental model of the northward migration is described in which the compartments are zones of constant latitudinal width. Assumptions made for each zone are similar to those made for the Baranov catch equation, in which the population decays exponentially through constant instantaneous rates of natural mortality, fishing mortality and emigration. However, in addition to these assumptions, emigration from each zone is assumed to replenish the population in the next zone to the north. This results in the dynamics of the population being described by a system of constant-coefficient linear first-order differential equations. The solutions of this system and of equations for cumulative catch are given in a form that allows the model to be generalized to other migration patterns as a multi- zone analogue of the Baranov catch equation. A discretized form of the model with a restricted parameterization is used to analyse tag-return data from four tag releases. Estimated parameters are used in a yield-per-recruit analysis of prawns recruited to the ocean fishery from Botany Bay.
Biomass assessment of a deep-water fish, the orange roughy (Hoplostethus atlanticus), based on an egg survey
Authors: Koslow JA , Bulman CM , Lyle JM , Haskard KA
Published: November 2005

An egg survey was carried out in 1992 to estimate the biomass of the orange roughy stock that spawns off north-eastern Tasmania. Spawning occurs at depths of 700-1000 m around a single seamount from early July through early August. Orange roughy have determinate fecundity, and their fecundity and the depth distribution and development rate of the eggs are described elsewhere. A random stratified survey was designed for a limited area around the spawning site in order to sample the eggs fully during their first day of development. The eggs were sampled with vertical tows from 1000 m to the surface. There was no evidence of significant mortality or other egg loss during the first day after spawning, when the eggs are mostly below 400 m. Subsequently, egg numbers declined rapidly at an instantaneous loss rate of 0.036 h-1, primariIy through advection out of the survey area. The estimated biomass of spawning fish was 27 445 t. From the proportion of non-spawning fish in the population (29% of females and 10% of males) and estimated catch of spawners, total mid-season stock biomass in 1992 was estimated to be 34 593 t with a coefficient of variation (CV) of 47%. A bootstrap estimate of the variance indicated a somewhat lower CV of 41%. The point source of spawning activity appears to give rise to a highly patchy egg distribution, which results in the high variance of the biomass estimate. From the catch history of the fishery, virgin biomass of the stock was estimated to be approximately 96 900 t, and the stock was at 28% of virgin biomass at the end of season. An acoustic survey of the spawning orange roughy provided a similar estimate of stock size. The acoustic survey had greatly reduced statistical confidence limits (CV = 6%) but far greater non-statistical sources of uncertainty, i.e. the species composition of acoustic targets and the target strength of these species.
Distribution of organochlorines, polycyclic aromatic hydrocarbons, phosphorus and 137Cs in sediment profiles from Ellen Brook in Western Australia
Authors: Gerritse R , Hernandez F , Murray AS , Wallbrink PJ , Brunskill G
Published: November 2005

Profile distributions are compared of organochlorines (OCs), unsubstituted polycyclic aromatic hydrocarbons (PAHs), phosphorus and 137Cs and 210Pb in sediment cores from Ellen Brook, a tributary of the Swan River in Western Australia. Distributions and concentrations of OCs, phosphorus and 137Cs clearly reflect changes in their inputs to the catchment over time, whereas the distribution and concentration of PAHs in sediments is more difficult to relate to catchment inputs. A comparison of areal concentrations of 137Cs, OCS and PAHs - calculated from concentrations in sediment profiles from Ellen Brook - suggests that 137Cs and OCs trace similar soil materials, whereas PAHs behave differently.
Speculations on a spatial memory for the Port Jackson shark (Heterodontus portusjacksoni) (Meyer) (Heterodontidae)
Authors: O'Gower AK
Published: November 2005

SCUBA observations show that Port Jackson sharks repeatedly visit specific resting sites on ocean reefs at South Bondi (New South Wales) and, when disturbed, move directly from one site to another. The sharks also use specific resting sites in Sydney Harbour and, when transferred by boat to different localities within the harbour, up to 3 km away, return to their original resting sites. The sharks migrate from as far south as Tasmania to Sydney Harbour to lay their eggs in specific sites. Speculative extrapolation from the above observations suggests that Port Jackson sharks must have a highly developed spatial memory.
Diets of, and trophic resources exploited by, bathyal penaeoidean shrimps from the western Mediterranean
Authors: Cartes JE
Published: November 2005

The stomach contents of 115 specimens of Aristaeomorpha foliacea, 67 specimens of Parapenaeus longirostris, and 122 specimens of Solenocera membranacea were examined to establish the composition of the diets. All material was collected by bottom trawls at depths between 198 and 590 m in the Catalan Sea during 1991-93. S. membranacea and P. longirostris had highly diversified diets based mainly on benthic organisms (polychaetes, bivalves, gastropods and echinoderms). In addition, the diet of P. longirostris also included suprabenthic organisms (mainly gammarid amphipods) and a small proportion of pelagic organisms. These two penaeoidean species had high stomach fullness index values. Both trophic diversity and stomach fullness index values were lower in A. foliacea than in the other two penaeoidean species. A. foliacea is a highly specialized feeder on pelagic and suprabenthic organisms (i.e. euphausiids, isopods, Plesionika martia). Thus, a disparity in the food resources exploited was recorded for the three penaeoidean species. Analysis of the diets of Mediterranean bathyal penaeoideans yielded characteristically high values of H' of around 5 or above, substantially higher than the values for other bathyal decapod species in the same region. This finding may be generally typical of penaeoidean species in other geographical regions in both the bathyal and the abyssal zones as well as in shallow waters.
Calcium accumulation during the transition from puerulus to juvenile in the western rock lobster, Panulirus cygnus (Decapoda: Palinuridae)
Authors: Lemmens JWTJ
Published: November 2005

Dry weight in P. cygnus increases from 58.4 � 5.4 mg in pueruli to 88.5 � 11.9 mg in first-moult juveniles. Changes in ash-free dry weight, from 51.2 � 4.9 mg in pueruli to 56.7 � 9.5 mg in first-moult juveniles, are insufficient for the increase in dry weight to be attributable to accumulation of organic matter. The ash weight increased substantially after ecdysis of the puerulus (6.9 � 2.3 mg for pueruli; 31.9 � 2.8 mg for first-moult juveniles). This change may be attributed to the process of mineralization, which involves accumulation of calcium salts, and other mineral salts, as well as a range of organic components. Calcium contents, measured with flame emission, increased from 0.46 � 0.06 mg in pueruli to 1.59 � 0.26 mg in first-moult juveniles.
Histological studies showed substantial calcium deposits in the gastric mill and mouth region of the juvenile but not of the post-settlement puerulus. Since internal calcium reserves are small in the puerulus, calcium may initially be taken up directly from the sea water following ecdysis.
Temporal and spatial variability in community structure of a sandy intertidal beach, Cape Paterson, Victoria, Australia
Authors: Haynes D , Quinn GP
Published: November 2005

The infauna of a sheltered sandy intertidal beach at Cape Paterson, Victoria, was sampled on a three-monthly basis over a two-year period. In total, 116495 individuals comprising 41 species were collected over this time. Common species collected included the dipteran Chaetocoelopa sydneyensis, the coleopteran Sphargeris physodes, the isopods Pseudolana concinna and Actaecia thomsoni, the amphipods Talorchestia cf. novaehollandiae and Exoediceroides maculosus, and the polychaetes Magelona sp. and Scolelepis lamellicincta. There were significant differences in infaunal densities and species richness between the beach heights sampled, with both factors increasing with decreasing beach height over the intertidal zone. In generaI, insects were confined to upper beach heights, polychaetes were confined to lower beach heights, and different crustacean species spanned the entire intertidal beach. Significant temporal differences also existed in infaunal densities and species numbers at most of the beach heights sampled. These temporal differences were related to changes in the densities of common intertidal species. Only four of these common species (S. physodes, C. sydneyensis, T. cf. novaehollandiae and E. maculosus) exhibited any seasonal pattern in this temporal variation in density. Multivariate analysis of infaunal data failed to consistently separate beach heights into the universal zones previously proposed for sandy intertidal habitats. The unpredictable nature of biotic and abiotic influences on sandy intertidal infauna makes it unrealistic to expect to be able to consistently separate faunal assemblages on any given sampling occasion, with the exception of a characteristic fauna with terrestrial affinities that is confined to the upper beach. Any zonation patterns identified as being present on sandy beaches need to be qualified by the time of year in which data were collected.
Evaluation of subcutaneously implanted visual implant tags and coded wire tags for marking and benign recovery in a small scaleless fish, Galaxias truttaceus (Pisces: Galaxiidae)
Authors: Crook DA , White RWG
Published: November 2005

Visual implant (VI) tags and coded wire tags (CWTs) were tested as methods for marking a small galaxiid fish, Galarias truttaceus, in such a way as to allow benign information recovery. VI tags were implanted beneath the skin of the preoperculum and CWTs were implanted between caudal fin rays. Both types of tag were easily implanted into fish >90 mm total length (4-5 g). Retention rates of both tag types were evaluated under field conditions. Retention of VI tags implanted in the preoperculum was estimated at 100% after 14 days and 92% after 131 days. There was a loss of 8-18% of CWTs within the first four weeks after tagging. Tag loss continued more gradually thereafter and retention was estimated at 71% after 131 days. It was demonstrated that both types of tags could be applied successfully to four other species of Galaxias.
Salinity tolerance and osmoregulation in the silver perch, Bidyanus bidyanus Mitchell (Teraponidae), an endemic Australian freshwater teleost
Authors: Guo R , Mather PB , Capra MF
Published: November 2005

Juvenile silver perch, Bidyanus bidyanus, were subjected to direct transfer from fresh water to various test salinities. No mortality was observed when the fish were transferred from fresh water to a salinity of 12, but 40% mortality was observed at a salinity of 15 after seven days. Pre-acclimation of silver perch to a salinity of 12 for seven days resulted in only marginally better survival at higher salinities. Plasma osmotic concentrations of silver perch rose slightly in salinities below 9 but rapidly at higher salinities, following the same track as the iso-osmotic line. Minimum body water content was observed in individuals subjected to a salinity of 15 for 24 h. As found in other freshwater teleosts, chloride cells were found in the branchial epithelium of silver perch. Accessory cells were observed beside the chloride cells in both freshwater and salt-water conditions. Fish subjected to a salinity of 12 for seven days showed chloride cells with a more developed tubular system than controls. The length of the junctions between chloride cells and accessory cells was significantly shorter in fish adapted to a salinity of 12 than in controls. The ultrastructural feature of 'interdigitations' of accessory cells was not observed during salt-water adaptation. These data indicate that silver perch is the least tolerant of high salinities and the most truly freshwater Australian teleost species examined to date.
A trouser-trawl experiment to assess codends that exclude juvenile mulloway (Argyrosomus hololepidotus) in the Hawkesbury River prawn-trawl fishery
Authors: Broadhurst MK , Kennelly SJ
Published: November 2005

A trouser trawl was used to assess two codends designed to reduce the by-catch of juvenile mulloway in the Hawkesbury River prawn-trawl fishery. Simultaneous comparisons were made between the catches and by-catches from each codend with those from a conventional codend. The new design incorporated a panel of netting (40-mm mesh or 85-mm mesh) sewn such that the meshes were square-shaped. The panel was placed into the top of the anterior section of the codend to allow water and swimming fish to escape through these larger openings while allowing prawns to tumble along the conventional diamond-shaped netting (40-mm mesh) on the bottom of the codend (and be retained in the posterior section). Comparisons with a conventional codend (in which all meshes were diamond-shaped) showed that the codend with the 40-mm square-mesh panel reduced the by-catch of small mulloway by a mean of 44% without significantly reducing the catch of prawns. The 85-mm square-mesh panel was excluded from analysis, owing to problems associated with its construction.
The Freshwater shrimp Paratya australiensis (Kemp, 1917) (Decapoda:Atyidae) in estuaries of south-westren victoria, Australia
Authors: Walsh CJ , Mitchell BD
Published: November 2005

All life-cycle stages of Paratya australiensis, formerly thought to occur predominantly in freshwater environments, were found to be common in estuaries of western Victoria. Highest densities of larvae were found below the halocline in stable, open, well developed, salt-wedge estuaries. Larvae developed in the salt wedge, and juveniles recruited to littoral weed beds. Adults were most abundant in low salinities among submerged, leafy macrophytes. Although recruitment to estuaries permits the avoidance of fatal drift of larvae to sea, tolerance of saline conditions may permit rare dispersal of larvae between estuaries. A new model for the biogeography of Paratya is proposed.
Swimming, feeding, circulation and vision in the Australian box jellyfish, Chironex fleckeri (Cnidaria:Cubozoa)
Authors: Hamner WM , Jones MS , Hamner PP
Published: November 2005

Juvenile Chironex fleckeri medusae were maintained in aquaria for several months. One individual was raised over a nine-month period to subadult condition for the first time. The medusae did not feed naturally in most aquaria but they accepted and digested prey items placed by hand onto the manubrium. Medusae maintained in planktonkreisels, however, extended tentacles and captured and ingested live Acetes, large prawns and fish by subumbrellar flexing of the pedalia. Digestion of prey was rapid and food particles were circulated directionally through functional canals and lacunae primarily by contractions of the bell but also by peristaltic contractions of interradial gastrovascular tissues. In the laboratory, medusae visually reacted to dark objects by swimming away from them. Swimming behaviour of medusae in the sea and natural predation by green turtles (Chelonia rnydas) on C. fleckeri are described.
Reproductive biology of the protogynous hermaphrodite Achoerodus viridis (Labridae) from south-eastern Australia
Authors: Gillanders BM
Published: November 2005

Achoerodus viridis (Pisces : Labridae) was sampled over two years at Little Bay, NSW, Australia, and comparative material was taken from a site 4.5 km away at Cape Solander. Population structure and gonadal structure showed that A. viridis was protogynous and monandric (i.e. no primary males were found). Histological sections of male gonads showed a gonadal lumen, general ovarian lamellar form and multiple sperm ducts running longitudinally through the gonad wall. Males dominated the larger size and age classes, whereas females predominated in the smaller size and age classes. The sex ratio of mature fish and the whole population was biased in favour of females. Individuals at both sites matured as females at 1+-2+ years. Fish at Little Bay functioned as females at ages ranging from 8+ to 18+ years before changing sex at a size between 480 and 580 mm SL. Fish at Cape Solander may function as females for up to 18+' years and change sex between 500 and 520 mm SL. Spawning occurred between July and October (1991-93).
Feeding ecology of the temperate marine fish Achoerodus viridis (Labridae): Size, seasonal and site-specific differences
Authors: Gillanders BM
Published: November 2005

Fish were collected from localities in the Sydney region, New South Wales, Australia, from March 1991 to September 1993. Achoerodus viridis is a benthic carnivore and consumes a wide variety of prey items. Size-specific differences in diet were found. The diet of recruits (17-26 mm SL) collected in seagrass environments was dominated by tanaids, whereas that of rocky reef recruits was dominated by harpacticoid copepods. The diet of rocky reef fish then shifted to gammarid amphipods and other crustaceans (fish 50-150 mm SL) and to mussels and urchins (fish >300 mm SL). Juvenile fish on rocky reefs (450 mm SL) foraged in shallow fringing habitat, whereas adult fish (>200 mm SL) foraged in deeper turf and barrens habitats, reflecting the depth distribution of the species. Feeding rate of larger fish tended to be less than that of smaller fish. Variations in diet and feeding rate were also detected over the year but the patterns were not consistent between years. Among sites, there were differences in diet but these were not related to the position of sites inside an estuary or on the open coast. The results of this study provide information on the feeding ecology of a large labrid fish; this information will aid in understanding the population dynamics of the species.
Distribution of aquatic pulmonate snail species in contrasting habitats within the Ross River Reservoir (stage 2a), tropical Northern Australia
Authors: Hurley M , Hearnden MN , Kay BH
Published: November 2005

Monthly distributions of three snail species in three distinct habitat types from February 1992 to May 1993 were found to be variable, with peak abundances occurring predominantly in the late wet season (March to May) for Amerianna carinata and Gyraulus gilberti and in the late dry season (September to November) for Austropeplea lessoni. No consistently positive or negative patterns of correlation were recorded between numbers of snails and physico-chemical characteristics or the amount or composition of emergent and submerged macrophyte species. However, highest densities of A. lessoni and A. carinata were recorded in temporary ponds, where the biomass of periphyton was greatest. Significantly lower amounts of periphyton were recorded from open bays and permanent creeks. Highest densities of G. gilberti occurred in permanent creeks. Physico-chemical variables, rainfall patterns and macrophyte species were not good indicators of snail abundance in the Ross River reservoir. The best indicator of snail density appeared to be whether vegetated habitat is located within open bays, permanent creeks or isolated peripheral ponds.
Phosphorus speciation in the Williams River, New South Wales: Eutrophication and a chemometric analysis of relationships with other water quality parameters
Authors: Nolan AL , Lawrance GA , Maeder M
Published: November 2005

Phosphorus concentrations as both total phosphorus and partitioned (dissolved, 'bioavailable' and 'available-reactive') phosphorus have been determined in a quality-controlled study of the Williams River in the Hunter Valley, Australia, at Boags Hill during a five-month period. Complementary analyses of each sample for a range of standard water quality parameters were also obtained. Strong interrelationships between total phosphorus and partitioned phosphorus suggest that total phosphorus alone may be as adequate an indicator of potential algal growth as bioavailable phosphorus in this river system, an outcome supported by limited algal bioassay results. Principal component or factor analysis of the complete data set allowed qualitative insight into the relationship between the different concentrations (relevant cations and anions) and other measurements (colour (apparent), turbidity, etc.). Compounds from similar sources are clustered in the principal component plots. The samples taken over a specific time period have been analysed in a similar way, with clustering according to rainfall patterns being clearly indicated.
Role of recruitment and growth in determining the upper limit of distribution of the intertidal barnacle Hexaminius popeiana
Authors: Coates M , McKillup SC
Published: November 2005

The barnacle Hexaminius popeiana occurs in a zone up to approximately 3.7 m above chart datum on the trunks of mangrove trees in eastern Australia. Recruitment density of H. popeiana declined sharply with tidal height, and almost no recruitment occurred above the upper limit of distribution of sessile adults. Nevertheless, settlement of H. popeiana above the upper limit could be induced by the presence of adults, and there was little difference in the survival of either transplanted or induced recruits within, compared with above, the natural distribution. Surprisingly, therefore, no change in the upper limit of H. popeiana occurred, despite several episodes of recruitment during a two-year study. Factors that may act to restrict recruitment to substrata within the adult distribution are discussed. Growth rate was reduced and sexual maturity delayed at upper compared with lower tidal heights. An evolutionary cost of settling above the adult distribution appears to be delayed sexual maturity and reduced production of offspring, rather than post-settlement mortality per se.
Seasonal water regimes and leaf litter processing in a wetland on the Swan Coastal Plain, Western Australia
Authors: Ryder DS , Horwitz P
Published: November 2005

The effect of seasonal or permanent inundation on the processing of leaf litter from two emergent macrophytes, Baumea articulata and Typha orientalis, was examined at Lake Jandabup, a seasonal wetland on the Swan Coastal Plain. Leaf litter processing was quantified through the loss of organic matter from leaf packs. The contribution made by microorganisms was also examined.
Leaf packs exposed to seasonal inundation had significantly higher losses of organic matter after six months than did those permanently inundated, with B. articulata leaf packs losing significantly more. The presence of a diurnally stratified water column in permanently inundated sites in summer, resulting in reduced oxygen concentrations at the bottom of the water column, may be responsible for lower organic matter loss in this environment. These results are supported by the presence of organic-rich soils at permanently inundated sites and their absence at seasonally inundated sites, indicating a long-term pattern of leaf litter processing and wetland water regimes. The distribution of organic-rich soils in wetland basins may provide an indication of long-term water level regimes and can therefore provide a valuable tool for determining water regimes in artificially maintained or restored wetlands.
Seasonal variation in the species and size composition of the clupeoid assemblages in Western Port, Victoria
Authors: Hoedt FE , Dimmlich WF , Dann P
Published: November 2005

The size composition of three species of clupeoid fish was monitored from monthly samples taken between May 1992 and April 1994 in Western Port, Victoria. Anchovy and pilchard were the dominant species in most samples and sandy sprat were occasionally common. Seasonal variations in catches indicate that adult clupeoids are temporary inhabitants in Western Port, migrating into the bay between October and December and leaving between February and June. Juvenile anchovy and pilchard were common in catches between February and April, indicating that Western Port serves as a nursery area for both species. Sizes of adult anchovy and pilchard collected in Western Port were at the lower end of the known range and these probably represent a single age-group of young adult fish. Comparisons with published data from Bass Strait and Port Phillip Bay show the importance of different habitats for different sizes of clupeoids in western Victoria.
Comparison of rapid methods for sampling the pipi, Donax deltoides (Bivalvia: Donacidae), on sandy ocean beaches
Authors: James RJ , Fairweather PG
Published: November 2005

Two rapid methods for sampling Donax deltoides that do not involve sieving sand were compared on a sandy ocean beach in Australia. 'Finger-dredging' of saturated sand in box-quadrats recovered almost 100% of D. deltoides and sampled individuals of all sizes (6 to 55 mm). This method provides the same information as traditional sieving techniques but is faster and should be generally useful for sampling bivalves on sandy beaches. The accuracy of finger-dredging 0.1 m² and 0.2 m² box-quadrats was similar. Sampling was often more efficient with the smaller rather than the larger quadrat, but differences between quadrat sizes varied among levels on the beach. The 0.1 m² quadrat was also preferred because it was fastest and easiest to use and therefore more replicates could be taken per unit sampling time. Tests of a 'knife method' showed that the mean frequency of D. deltoides hit by running the knife through the sand and the mean density of D. deltoides (determined independently) were significantly correlated, but not strongly enough to provide reliable information on abundances. This method adequately sampled only D. deltoides of lengths greater than about 30 mm and was less sensitive in gravelly or saturated sand than in clean, dry sand. The knife method may, however, be useful for studies of the distribution of size classes of large pipis.
Distinctive aspects of the zooplankton of large lakes in Australasia, Antarctica and South America
Authors: Bayly IAE
Published: November 2005

Not only has the degree of species-level cosmopolitanism amongst zooplanktonic organisms been considerably overestimated, but differences between the different classical biogeographic regions (established from terrestrial studies) occur at supra-specific levels as high as family or even suborder. The Centropagidae, and particularly the genus Boeckella, are found in New Zealand, most of Australia, southern and high altitude regions of South America, and around the periphery of Antarctica. The biogeography and ecology of this family is discussed in detail. Most predaceous families of Cladocera are entirely absent from the Australian and Neotropical regions. The genus Daphniopsis occurs in salt lakes in Australia and South America and in freshwater lakes in Antarctica. In southern Australia numerous species of ostracod have colonized the limnetic region of salt lakes, and the largest of these prey on species of Calamoecia, Daphniopsis and small ostracods. Chaoboridae are absent from New Zealand as, too, are obligate planktivorous fish. The Chilean flamingo, Phoenicopterus chilensis, and Wilson's phalarope, Phalaropus tricolor, are significant predators on Boeckella poopoensis in salt lakes on the Andean Altiplano and elsewhere in South America.
Coral communities of the Gneering Shoals and Mudjimba Island, south-eastern Queensland
Authors: Banks SA , Harriott VJ
Published: November 2005

The Gneering Shoals and Mudjimba Island are coastal rocky-reef communities approximately 250 km south of the Great Barrier Reef. Ten sites from 700 m to 12 km offshore were investigated with the use of video-transects to determine percentage cover of benthic organisms. The marine benthic communities were dominated by hard corals, soft corals and turf algae. Three community types were identified: (1) offshore communities, (2) island-associated communities, and (3) a nearshore algae-dominated community. Inshore sites were dominated by flat encrusting hard corals, whereas offshore sites were dominated by foliose and plating hard corals, particularly Acropora solitaryensis and Turbinaria spp. There was a notable scarcity of branching species, particularly from the Family Acroporidae. Seventy-seven species of scleractinian coral, representing 30 genera in 11 families, have been recorded from the Gneering Shoals region. The Gneering Shoals had low coral species richness relative to the southern Great Barrier Reef (244 species) and Flinders Reef, 50 km to the south-east (118 species). Possible explanations for the relatively low coral species richness in the Gneering Shoals region include the physical attributes of the site and the hypothesized failure of the East Australian Current to be a major influence on the region.
Elevated sea-water temperature and solar UV-B flux associated with two successive coral mass bleaching events in Tahiti
Authors: Drollet JH , Faucon M , Martin PMV
Published: November 2005

After a minor coral bleaching event in 1993, a more dramatic episode occurred in Tahiti from March to July 1994. Coral bleaching was recorded along four continuous 25-m-long line transects. Physico-chemical parameters of the sea water (temperature, salinity, dissolved oxygen and pH) were noted once a week, and solar UV-B flux was recorded daily before and during the bleaching episode. Results emphasized the importance of the taxonomic position of coral in susceptibility to bleaching. The evolution of bleaching through time was related to mean daily solar UV-B flux and sea-water temperature. Moreover, comparison of the 1993 and 1994 data suggested temperature and/or UV-B thresholds that may elicit minor or severe bleaching events.
Life history, food and habitat of southern pygmy perch, Nannoperca australis, in the Macquarie River, Tasmania
Authors: Humphries P
Published: November 2005

The reproductive biology, age, growth, food and habitat of Nannoperca australis are described from samples collected from fringing macrophyte beds of the Macquarie River, Tasmania. Comparisons are made with the same species at Narrandera in New South Wales and other nannopercids, mainly in south-western Australia. Nannoperca australis spawned at the end of its first year, predominantly between October and December, inclusive. The peak mean gonadosomatic index of males occurred in August at 8.0 and that of females two months later at 11.5. The largest oocytes, of running-ripe females collected in October and December, were 1.15 mm in diameter. Fecundities ranged from 78 for a 1-year-old 37-mm fish to 679 for a 2-year-old 63-mm fish. Spawning is presumed to occur in the macrophyte habitat, since adults did not emigrate from these areas at this time. Otoliths and length-frequency histograms indicated that populations were dominated by 0+ fish. Amphipods and ostracods predominated in the guts of N. australis and prey items were mostly either benthic invertebrates or plant epifauna. Plankton was consumed by small fish in greater quantities than by larger fish, whereas the opposite was true for benthic and epifaunal prey. Fish were virtually always associated with aquatic macrophytes and almost always with shallow, still water.
Effect of carp, Cyprinus carpio L., an exotic benthivorous fish, on aquatic plants and water quality in experimental ponds
Authors: Roberts J , Chick A , Oswald L , Thompson P
Published: November 2005

The effects of carp, Cyprinus carpio L., on water quality and functioning of aquatic systems were investigated in two experiments in ponds (~90 cm deep) outdoors at Griffith, New South Wales. The experiments represented contrasting conditions of high and low impact, defined by stocking density and food availability, with stocking densities chosen to be above and below 450 kg ha-1, the stocking density suggested as a critical threshold for damage. Under high impact conditions, carp had a significant effect on water quality, habitat structure and pond physical characteristics. Turbidity increased from approximately 7 NTU to 26 and 73 NTU by Day 4, there was a complete loss of two out of five plant species tested (Chara fibrosa and Vallisneria sp.) by Day 6, and surface water temperature in ponds with carp was significantly greater by Day 7. Plant loss was attributed to uprooting rather than herbivory, as sometimes reported. Under low impact conditions the uprooting rate of Vallisneria was reduced to a third. Contrary to the results of previous studies, there was no evidence of increased nutrients or greater algal biomass in ponds with carp, but this may have been because the sediments were relatively low in phosphorus. A crude nutrient budget based on water concentrations and tissue analysis showed substantial growth of carp in 20 days that could be accounted for only by considering either sediments or terrestrial inputs (ponds were not covered) as an important food source.
Ostracod fauna associated with sublittoral kelp forest vegetation at Windang Island, New South Wales, Australia
Authors: Yassini I , Jones BG , King RJ , Ayress M , Dewi KT
Published: November 2005

Sublittoral kelp forests, such as those occupying the wave-dominated shallow marine rocky substrata around Windang Island, New South Wales, provide an important habitat for ostracods. This is reflected in the diverse biocoenotic assemblage (69 species, including one new genus and three new species) and populations of juveniles recorded from this area. The thanatocoenotic assemblage contributes a further 37 ostracod species. The total assemblage is more diverse than, and has only 17 species in common with, the previously documented intertidal biocoenotic assemblages around Windang Island. The distribution of the more abundant ostracod species reflects the energy levels within the environment, with a greater proportion of smooth-shelled forms occurring in the higher-energy zones at shallow depths. Most of the thanatocoenose population represents species moved up from the deeper shelf or into the region from the adjacent tidal channel into Lake Illawarra, rather than species from the intertidal region around Windang Island.
Assessment of genetic variation in wild populations of the redclaw crayfish (Cherax quadricarinatus, von Martens 1868) by means of allozyme and RAPD-PCR markers
Authors: Macaranas JM , Mather PB , Hoeben P , Capra MF
Published: November 2005

The population structure of the redclaw crayfish (Cherax quadricarinatus) was investigated by analyses of allozymes and RAPD (randomly amplified polymorphic DNA) markers. Electrophoretic analysis of 28 enzyme loci in 12 redclaw populations from the Northern Territory (NT) and North Queensland (NQ) revealed generally low estimates of heterozygosity within each population and low estimates of genetic differentiation among populations except for a fixed allelic difference at the carbonic anhydrase (CA*) locus between NT and NQ populations. Low levels of genetic variability among the NQ populations is possibly a reflection of their recent radiation across the Gulf of Carpentaria after its inundation between 18000 and 6000 BP. RAPD analysis of seven redclaw populations could distinguish each river population and also grouped them according to geographic proximity. RAPD analyses also revealed significant genetic variability both within the species and within individual populations, which could be used to improve their culture. On a preliminary scale, RAPD fragments provided a useful tool for differentiating redclaw strains and constitute a marking system that could be used in crayfish genetic improvement programmes.
Determination of the aluminium complexing capacity of fulvic acids and natural waters, with examples from five New Zealand rivers
Authors: Hawke DJ , Powell KJ , Gregor JE
Published: November 2005

An FIA technique with 7 s reaction time was used to analyse free plus labile Al in fulvic acid (FA) solutions and natural waters at pH 4.7, without the need for separation procedures. Titrations of these solutions using incremental pH or total Al were used to determine pH binding curves or estimates of the 'kinetic' Al complexation capacity (Al-CCk) respectively. The operational definition of Al-CCk relates to the capacity of a humic substance or natural water to bind Al through a 7-s FIA reaction time under defined experimental conditions of chromophore (CAS) concentration, ionic strength, and pH. Both Al binding strength and complexation capacity were greater than the corresponding Cu-CC (ISE) values. The Al-CCk measurements at pH 4.7 were 710 μmol Al g-1 v. 590 μmol Cu g-1. Al-CCk results (pH 4.7) were higher for soil FA (710 μmol g-1) than for aquatic FA (390 μmol g-1). Al-CCk results (pH 4.7) for five unfiltered river waters from different catchments gave results in the range 6.5-9.8 μmol Al L-1. The differences between total (natural) Al in the samples and Al-CCk were between 2.7 μM and 8.6 μM. Filtration experiments identified fractionation patterns between total (natural) Al and the fraction of Al-CCk not utilized. The Al titration of alginate, another component of natural organic matter, is reported.
Lunar periodicity in catch rate and reproductive condition of adult eastern king prawns, Penaeus plebejus, in coastal waters of south-eastern Queensland, Australia
Authors: Courtney AJ , Die DJ , McGilvray JG
Published: November 2005

This study examined the lunar and die1 variation in catch rates and reproductive condition of adult eastern king prawns, Penaeus plebejus, in relatively deep (160 m) coastal waters off south- eastern Queensland. Females numerically dominated catches over most of the lunar cycle and constituted 76% of the weight of the catch. Analysis of variance (ANOVA) revealed an interaction between lunar phase and sex; catches peaked during Lunar Phase 3 (full moon � 3 days) and were particularly marked for males. This was the only period during the lunar cycle when the sex ratio approached 1 : 1. There was also an interaction between trawl-time and sex; male catch rates were at a minimum early in the evening, whereas female catch rates were at a maximum then and declined throughout the night. Trawler logbook catch rate data from the same area over a similar period indicated an interaction between lunar cycle and lunar phase. ANOVA revealed an effect of the interaction between phase and sex on the incidence of soft prawns; the incidence of soft males increased during Phase 4 (half moon waning to new moon � 3 days). Ovary weight also varied between phases and was higher during Phases 2 (half moon waxing to full moon � 3 days) and 4 (half moon waning to new moon � 3 days). Trends in the ovary weight and the incidence of histologically mature and ripe females suggested there are two periods of increased spawning activity during each lunar cycle. A cyclic regression fitted to the data explained 93% of the variation in the incidence of ripe females between samples. The influence of these cyclic trends in catch rate and reproductive condition should be considered when monitoring the spawning stock in the fishery and when planning sampling strategies in any future reproductive studies.
Stock-recruitment relationships of the tiger prawns (Penaeus esculentus and Penaeus semisulcatus) in the Australian northern prawn fishery
Authors: Wang YG , Die D
Published: November 2005

This paper investigates the stock-recruitment and equilibrium yield dynamics for the two species of tiger prawns (Penaeus esculentus and Penaeus semisulcatus) in Australia's most productive prawn fishery: the Northern Prawn Fishery. Commercial trawl logbooks for 1970-93 and research surveys are used to develop population models for these prawns. A population model that incorporates continuous recruitment is developed. Annual spawning stock and recruitment indices are then estimated from the population model. Spawning stock indices represent the abundance of female prawns that are likely to spawn; recruitment indices represent the abundance of all prawns less than a certain size.
The relationships between spawning stock and subsequent recruitment (SRR), between recruitment and subsequent spawning stock (RSR), and between recruitment and commercial catch were estimated through maximum-likelihood models that incorporated autoregressive terms. Yield as a function of fishing effort was estimated by constraining to equilibrium the SRR and RSR. The resulting production model was then used to determine maximum sustainable yield (MSY) and its corresponding fishing effort (fMSY).
Long-term yield estimates for the two tiger prawn species range between 3700 and 5300 t. The fishing effort at present is close to the level that should produce MSY for both species of tiger prawns. However, current landings, recruitment and spawning stock are below the equilibrium values predicted by the models. This may be because of uncertainty in the spawning stock-recruitment relationships, a change in carrying capacity, biased estimates of fishing effort, unreliable catch statistics, or simplistic assumptions about stock structure.
Although our predictions of tiger prawn yields are uncertain, management will soon have to consider new measures to counteract the effects of future increases in fishing effort.