bluuebunny/crossref_metadata_2025 huggingface dataset:
Ecology of juvenile and adolescent banana prawns, Penaeus merguiensis, in a mangrove estuary and adjacent off-shore area of the Gulf of Carpentaria. I. Immigration and settlement of postlarvae
Authors: Stapels DJ
Published: November 2005

The hydrology of the Norman River and adjacent off-shore region in the Gulf of Carpentaria is dominated by the alternation of a summer north-west monsoon and a winter south-east trade wind. The seasonality in both air temperature and rainfall is reflected in marked annual cycles of water temperature, salinity, and dissolved oxygen and nutrient (nitrate and silicate) levels. Near the mouth of the river; water temperature ranged from 15.0�C in June to 32.7�C in February, while salinity ranged from c. 0‰, in December and February to 38.2‰, in September. Postlarval banana prawns, P. merguiensis, were found in the river from November to May. but immigration was essentially restricted to the period immediately preceding the wet season (mid November). Maximum numbers ofjuvenile prawns occurred approximately 2 weeks later. A marked tidal periodicity in the movement of postlarvae was observed; postlarvae were present in the water column at the mouth of the river only during the flood tide with maximum numbers moving into the river at the time of maximum flood tide velocity. Incoming postlarvae settled out in the shallow water along the banks of the river (within 10 m of the shoreline), inland as far as 85 km. A lager catch of smaller prawns 48-72 km up-stream (salinity 10-20‰,) suggested that this area was the main settlement area for postlarvae. The population, however, contracted towards the river mouth during the wet season. concentrating the prawns in an area extending only a few kilometres up-river. Most prawns were caught on the muddy substrate adjacent to the mangrove (Avicennia sp.) fringe which lines the numerous bends in the river. Mechanisms for transporting larvae into the estuary and the relationship between the seasonality of physical and chemical parameters and immigration of postlarvae are discussed.
Ecology of juvenile and adolescent banana prawns, Penaeus merguiensis, in a mangrove estuary and adjacent off-shore area of the Gulf of Carpentaria. II. Emigration, population Structure and Growth of Juveniles
Authors: Staples DJ
Published: November 2005

Emigration of juvenile P. merguiensis from the Norman River was largely confined to the wet season; three main waves of emigration were observed, each corresponding to a period of heavy rain in December, January, and February. Following each period of rain, the prawns migrated in the surface waters of the estuary and became spread laterally across the river's width. The size of emigrating prawns decreased over the wet season, reflecting changes in both the size of prawns in the resident population and the strength of the stimulus to emigrate. During periods of low rainfall only a small number of larger prawns tended to migrate, whereas during high rainfall periods a mass movement of prawns of all sizes occurred. Examination of weekly changes in population structure showed that three main cohorts ofjuvenile prawns entered and left the river during the spring-summer period (November-February). The resident time of these prawns ranged from 1 to 9 weeks, depending on the timing of heavy rain during the period. Three smaller cohorts reached the river during March and April and the majority of these prawns did not emigrate but overwintered until the following spring. Growth during the summer period averaged an increase in carapace length of 1.2 mm/week, whereas growth in winter was slower in response to lower temperatures. After leaving the river, adolescent P. rnerguiensis spent a short time in the shallow beach zone near the mouth of the river before migrating off shore. The migration up until the time the prawns recruited into the off-shore fishery was estimated to take approximately 2 months. During this time the maximum growth was estimated as 15-mm increase in carapace length. The significance of these results is discussed in relation to the life history of the prawn in the south-eastern area of the Gulf of Carpentaria.
Seasonal fauna of ephemeral saline lakes near the Coorong lagoon, South Australia
Authors: De Deckker P , Geddes MC
Published: November 2005

Twenty-three ephemeral athalassic saline lakes near the Coorong lagoon, South Australia, were sampled monthly over 10 months in 1978-79. The numbers of species found were 16 ostracods, nine copepods, two anostracans, two cladocerans, one amphipod, one isopod, one gastropod, one nematode, one polychaete, two foraminiferans, one rotifer, and in addition ciliates, dipteran larvae, aquatic grasses and a charophyte. Ecological notes and data on salinity range for each species are presented. The affinities of the fauna and the means by which the species persist when a lake dries out are discussed.
Nematodes from scallops and turtles from Shark Bay, Westren Australia
Authors: Lester RJG , Blair D , Heald D
Published: November 2005

Between 1971 and 1978 up to 64% of commercial-sized saucer scallops, Amusium balloti, in samples from the landed catch at Shark Bay were infected with the larval ascaridoid nematode Sulcascaris sulcata. The presence of the nematodes and the brownish capsule in which they were found made some of the processed catch unsuitable for export. A small percentage of the scallops also contained a larval gnathostome, Echinocephalus sp. Five of six loggerhead turtles, Caretta caretta, from the same area were found to contain adult S. sulcata. Also present in the turtles were the cucullanid Cucullanus cauettae, the oxyuroid Kathlania leptura and the larval gnathostome Echinocephalus sp. Four of the turtles had been feeding chiefly on bivalves, one on crabs, and one on gastropods. Ulcers, probably associated with S. sulcata infection, occurred in the stomach, and small haemorrhages, probably associated with the feeding sites of C. carettae, occurred in the intestine.
Effect of a submerged reef chain on periods of sea-level oscillations in Western Australia
Authors: Tuck EO , Allison H , Field SR , Smith JW
Published: November 2005

A seiching type of sea-level oscillation recorded in Western Australia by Allison and Grassia (1979) is influenced by a submerged reef chain parallel to the shore. Being submerged, the reef chain forms an obstruction, causing the water between it and the shore to be partly open to the ocean. The effect of such a partial obstruction is studied in this paper, both theoretically and experimentally. Results indicate that even a comparatively small gap above the reef chain gives rise to periods of oscillations close to that of a fully open basin. On the other hand, presence of a comparatively smalI reef gives rise to seiching with periods nearly of the fully open basin, even in the case of the absence of a significant step to deep water in the bottom topography beyond the reef chain.
Relationship between concentration of heavy metals in muscle tissue and body weight of fish from the Swan-Avon estuary, Westren Austarlia
Authors: Marks PJ , Plaskett D , Potter IC , Bradley JS
Published: November 2005

In five species of teleost from the Swan-Avon river system (Mugil cephalus, Aldrichetta forsteri, Amniataba caudavittatus, Acanthopagrus butcheri and Nematalosa vlaminghi), the concentration of nine different heavy metals in muscle tissue either declined or remained relatively constant with increasing body weight. The data for the biologically important iron, zinc, copper and manganese were almost invariably represented better by a logarithmic rather than a linear regression. The concentration of these four metals generally ceased to change markedly with body size at weights above approximately 50 g. The mean concentrations of all nine heavy metals in those individuals heavier than 50 g were very low in every species and are probably close to the minimum levels found in these fish in unpolluted environments. The concentrations of heavy metals were greater in fish which ingested bottom material than in those which fed on organisms such as polychaetes. molluscs and crustaceans, and on various forms of plant.
Acute toxicity of selenium to three species of marine invertabrates, with notes on a continuous-flow test system
Authors: Ahsanullah M , Palmer DH
Published: November 2005

Acute toxicity of selenium (as sodium selenite) to three invertebrates common in Victorian coastal waters was determined using a continuous-flow test system. A description of the system is given. The three species were a cumacean, Cyclaspis usitata; juveniles of the bivalve Notocallista sp.; and two stocks of the laboratory-cultured amphipod Allorchestes compressa. Stock 1 of A. compressa was originally collected from Middle Spit, Western Port, and stock 11 from Somers, Western Port. The 96-h LC50 values for C. usitata, Notocallista sp. and stocks 1 and 11 of A. compressa were 6.12, 2.88, 6.17 and 4.77 mg selenium per litre respectively. The results indicated that juveniles of Notocallista sp. were more sensitive to selenium than adult A. compressa. The lack of information on the toxicity of selenium to invertebrates is indicated.
Benthic macrofaunal communities in the Tuggerah lakes, New South Wales
Authors: Powis BJ , Robinson KIM
Published: November 2005

The benthic macrofaunal communities of the Tuggerah Lakes were sampled using a diver-held corer. Communities were separated using DIVINF and MULCLAS classification techniques and the structure of the communities assessed using species number, diversity and evenness indices. Community structure was closely related to habitat type, seagrass substrates providing the greatest diversity compared with both mud and sand substrates. A flood during the sampling period affected the mud sites to a larger extent than seagrass sites, causing a decline in both species number and diversity. An effect of thermal power station effluent on shallow water community structure was observed and the implications of this are discussed.
Marine benthos from Davis Station, Eastern Antarctica
Authors: Everitt DA , Poore GCB , Pickard J
Published: November 2005

Marine benthos from 24 nearshore sites in the vicinity of Davis station, eastern Antarctica, was sampled from the sea-ice. The sediments were poorly sorted and mainly of wind-blown origin. Thirty-two animal taxa were recognized and most crustaceans were identified to species level. Three habitat types were characterized by their community composition and physical environment: (1) species-rich areas with abundant macrophytes; (2) deep anoxic muddy basins with deposit-feeding species; and (3) poorly sorted sands with mainly motile fauna. Two amphipod species were recorded as new for eastern Antarctica.
Vertical distribution of pilchard (Sardinops sagax) eggs and larvae off Southern Australia
Authors: Fletcher W. J.
Published: November 2005

Plankton samples were obtained from four to six discrete depths at 33 stations
in July 1994 by using the ‘EZ’ multiple
opening and closing net during a cruise along the shelf region from Adelaide
to Albany, southern Australia. At the 19 stations (88 tows) where pilchard
eggs were common, recently spawned eggs were most abundant at depths of
40–60 m, or 60% of total bottom depth. Most older egg stages were
found closer to, or at, the surface. During day-time, most pilchard larvae
were caught at the surface. At night, pilchard larvae appeared to spread out,
with lower overall rates of capture but a bigger proportion caught below the
surface. The effects of these changes in relative depth with age are discussed
in relation to the accurate estimation pilchard egg abundance for biomass
calculations.
Floodplain hydrology, acid discharge and change in water quality associated with a drained acid sulfate soil
Authors: Wilson B. P. , White I. , Melville M. D.
Published: November 2005

A two-year study of the relationships between water chemistry, hydrology and
climatology in areas of acid sulfate soils has demonstrated that discharge of
sulfuric acid to estuaries is not dependent solely on the magnitude of a
rainfall event. Large rain events did not always produce significant changes
to water chemistry, and small rain events could produce large changes if the
prevailing conditions were suitable. The magnitude of changes to estuarine
waters was found to be dependent on the position of the watertable, and
therefore the available soil pore space, and the store of acidic water in
floodgated drains at the time of rainfall. These results have significance for
predicting the discharge of acid drainage to estuarine environments and the
possible impacts on aquatic organisms. A water balance equation, which
estimated acid discharge to surface waters as high as 317 t of
H2SO4 in one month, can be used to
predict monthly discharges for rain events of varying magnitude if prevailing
weather conditions are known.
Bottom-driven upwelling generated by eastern intensification in closed and semi-closed basins with a sloping bottom
Authors: Herzfeld M. , Tomczak M.
Published: November 2005

Cold water is observed in the eastern Great Australian Bight, and the presence
of this water is inconsistent with that expected from surface Ekman-induced
upwelling resulting from the imposed windfield. A numerical model is employed
to investigate this situation under idealized conditions, from which the
bottom slope has been identified as the most dominant factor contributing
towards the presence of the cold water. A boundary current generated on the
eastern side of the idealized bight is attributed to eastern intensification
of a predominantly Stommel type, induced by the topographical gradient. It is
proposed that the cold water observed at the eastern boundary is the result of
upwelling driven by a bottom Ekman-transport convergence in this region, which
is in turn the result of a large bottom stress curl maintained by the eastern
intensification.
Fish ecology of a seasonal lowland stream in temperate South America
Authors: Almirón Adriana E. , García Mirta L. , Menni Roberto C. , Protogino Lucila C. , Solari Lia C.
Published: November 2005

El Pescado (literally ‘the fish’)
is a lowland stream in the pampean plain, entering the Rio de La Plata at
35˚55¢S,57˚45¢W, 70 km SW of the city of Buenos Aires. The
stream develops as a potamon with variable flood frequency along its 36 km
length. The water is slightly soft, with relatively high conductivity and
dominance of HCO–3 , Na
+ and Cl – ions. Three
fish families, Characidae (29%), Pimelodidae (14.6%) and
Loricariidae (12.8%) are most abundant among 55 species. Differences in
species composition among four stations with different environmental traits
were observed. Flooding slightly affected the fish fauna. In open-water and
rocky-bottom stations, both species number and number of individuals were
correlated with conductivity, an indication of the decrease of fish density
with floods. Species richness was well over worldwide means. Diversity values,
higher than in small tropical streams in Venezuela and southern Brazil, ranged
from 0.32 to 2.59, being higher during autumn and spring. The stream has a
high persistence, with the composition of the fish community maintained or
recovering as soon as flooding ends. One
Synbranchus marmoratus specimen was found among rocks,
the first record of this behaviour for the species.
Ecological and conservation significance of the subtidal rocky reef communities of northern New South Wales, Australia
Authors: Harriott Vicki J. , Banks Simon A. , Mau Roland L. , Richardson Darren , Roberts Lisa G.
Published: November 2005

The subtropical rocky reefs of Cook Island, Julian Rocks and the South West
Rocks area form part of a chain of islands and reefs with significant coral
cover from the Queensland border (28˚S) to the southern extent of
extensive coral communities in coastal Australia (31˚S). Benthic
communities at 18 subtidal sites at the three localities were surveyed
quantitatively by video-transects, and coral species lists were compiled.
Twenty-eight coral species previously unrecorded for these localities were
identified, increasing the species richness of hermatypic corals reported for
the northern NSW region (excluding the Solitary Islands) from 14 to 43. Coral
species richness declined with latitude. Benthic communities were generally
dominated by turfing and macroalgal species, with Pyura,
sponges, and barnacles locally abundant. Scleractinian coral cover ranged from
0% to 42.6% per site, with highest coral cover at the most
southern site. Julian Rocks is a designated Aquatic Reserve, and Marine Parks
have been suggested for all three localities. Selection of Marine Protected
Areas requires information on their ecological significance. These surveys
report the first quantitative information on the shallow- water, rocky-reef
communities in the region, which is a vital step in assessing their ecological
significance.
Estuarine spawning of the whitemouth croaker Micropogonias furnieri (Pisces : Sciaenidae), in the Río de la Plata, Argentina
Authors: Acha Eduardo M. , Mianzan Hermes , Lasta Carlos A. , Guerrero Raúl A.
Published: November 2005

Most fishes that take advantage of the high productivity of estuaries exhibit
offshore spawning, produce great numbers of small pelagic eggs and recruit to
estuaries as larvae or juveniles. The reproductive pattern of
Micropogonias furnieri (a planktonic egg spawner) in the
Río de la Plata estuary (36°S,56°W) differs from this.
Biological sampling and oceanographic data showed that the spawning area
covers a narrow band across the river between Montevideo
(34°50´8S,56°10´W) and Punta Piedras
(35°25´S,57°10´W) at depths ranging from 6 to 8 m. This
area is characterized by strong haloclines, reaching 21.5 units
m-1. M. furnieri eggs were present
only below the halocline, in salinities of 9.7–27.3, and at
18.5–20.2°C. Spawning occurred in the innermost part of the estuary,
near the upstream edge of the salinity wedge and coinciding with the turbidity
maximum (up to 150 mg L-1). The regular spawning of
pelagic eggs has been reported in estuaries of southern Africa and Australia
characterized by intermittent landlocking. The present results show that a
large estuary may also provide the opportunity for successful spawning of
pelagic eggs.
Resumen. La mayoría de los peces que aprovechan
la alta productividad de los estuarios efectúan sus desoves en el
océano, producen gran cantidad de pequeños huevos
pelágicos, y se reclutan a los estuarios como larvas o juveniles. El
patrón reproductivo de Micropogonias furnieri (un
desovante de huevos planctónicos) en el Río de la Plata
(36°S,56°W), resulta diferente. Muestreos biológicos y datos
oceanográficos demuestran que su área de desove cubre una
estrecha franja a través del río, entre Montevideo
(34°50´S,56°10´W) y Punta Piedras
(35°25´S,57°10´W), en profundidades de 6 a 8 m. Esta
área se caracteriza por fuertes haloclinas, de hasta 21.5 unidades
m-1. Los huevos de M. furnieri se
encuentran sólo debajo de la haloclina, en salinidades de 9.7 a 27.3, y
temperaturas de 18.5° a 20.2°C. El desove tiene lugar en la parte
más interna del estuario, cerca del límite río arriba de
la cuña salina, y en coincidencia con el máximo de turbidez
(hasta 150 mg L-1). En estuarios del sur de Africa y
Australia, caracterizados por el cierre intermitente de su boca, ha sido
reportado el desove regular de huevos planctónicos. Nuestros resultados
demuestran que un gran estuario también puede proveer la oportunidad
para el desove exitoso de huevos planctónicos.
Biology and fishery of pilchard, Sardinops sagax (Clupeidae), within a large south-eastern Australian bay
Authors: Neira Francisco J. , Sporcic Miriana I. , Longmore Andrew R.
Published: November 2005

Length–frequency and maturity data of pilchards
(Sardinops sagax) are described from monthly purse-seine
commercial catch samples obtained in Port Phillip Bay (Victoria) between
December 1994 and January 1997. These data, together with findings of a
12-month ichthyoplankton bay survey from September 1995 to August 1996, were
used to determine the size at which pilchards recruit to the bay fishery and
whether they spawn within this system. Monthly pilchard catch rates between
January 1990 and June 1996 are also described and analysed in terms of
environmental variables during that period. Results show that pilchards do not
generally attain sexual maturity or spawn within the bay but use it as a
nursery area, entering this system mostly as 0+ to 1+ year-o ld
juveniles (4–12 cm fork length, FL) in late spring–early summer
and returning to sea the following winter. This migration is supported by the
marked seasonality in catch rates, which each year peak in March–May and
are lowest in August–October. The seasonality was adequately explained
by temperature lagged 2 months in a multivariate time-series model. Port
Phillip Bay appears to be the only semi-enclosed, shallow marine embayment in
temperate Australia that supports a substantial pilchard fishery that, in
addition, is based predominantly on juveniles.
An allozyme study of the blue swimmer crab, Portunus pelagicus (Crustacea : Portunidae), in Australia: stock delineation in southern Australia and evidence for a cryptic species in northern waters
Authors: Bryars Simon R. , Adams Mark
Published: November 2005

Allozyme analysis was used to examine the species-level systematics and stock
structure of the Australian blue swimmer crab
Portunus pelagicus. Fifty-seven crabs from eight sites
were screened in an overview study for allozyme variation at 35 loci. This
overview study revealed the presence of two species, differing at a Nei
D of 0.14 (2% fixed differences), in the Darwin
region of northern Australia. One of these species corresponds to the common
P. pelagicus found throughout Australia, whereas the
other is most likely either an undescribed ‘cryptic’ species, or
the east-Asian species P. trituberculatus. In total, 609
P. pelagicus from 11 sites covering three regions in
South Australia and two regions in the Northern Territory were then genotyped
at seven polymorphic loci and these data assessed, using goodness- of-fit and
F-statistics, for the existence of subpopulations. Four
discrete subpopulations could be discerned, namely West Coast, Spencer Gulf,
and Gulf St Vincent in South Australia, and Darwin–Gove in the Northern
Territory. No evidence of population substructuring among sites within each
subpopulation was evident from the allozyme data. The results support the
current recognition of the three South Australian regions as separate stocks,
and suggest that a taxonomic revision of Indo-Pacific
Portunus is warranted.
Offshore wave climate, Perth (Western Australia), 1994 - 96
Authors: Lemm A. J. , Hegge B. J. , Masselink G.
Published: November 2005

The offshore wave climate of Perth (Western Australia) was analysed by using
2.5 years of non-directional 20-min wave data collected from March 1994 to
August 1996. The mean wave conditions are characterized by a significant wave
height (Hs) of 2.0 m and a
spectral mean wave period (Tm) of
8.8 s. However, considerable annual variation in the wave conditions is
experienced because of a distinct seasonality in the regional wind regime.
During summer, daily sea breezes generate moderate seas (ambient
Hs 1 to 2 m;
Tm <8 s). During winter,
frequent storms associated with mid-latitude depressions generate heavy seas
and swell (ambient Hs 1.5 to 2.5
m; Tm >8 s). A low-amplitude
background swell (Hs ~0.5 m),
generated distantly in the Indian and Southern Oceans, is present all year
round. Analysis of extreme wave conditions
(Hs >4 m) indicates that, on
average, 30 storms are experienced annually, and the storms are most frequent
and intense during July. Estimates of extreme
Hs, based on all available
offshore wave data (12 years, 1975–96), for 1- and 100-year return
periods, are 6.7 m and 9.8 m, respectively.
Settlement and recruitment of the abalone Haliotis cyclobates Péron, 1816
Authors: Stevenson Jonathon , Melville Andrew
Published: November 2005

The settlement preference, distribution and juvenile recruitment distribution
of Haliotis cyclobates were investigated in a seagrass
meadow in Gulf St Vincent, South Australia, in 1993 and 1994. Samples of hard
substratum and seagrass were collected from seagrass patches and open areas
and examined for newly settled and 0+ recruits. Hard substrata consisted
of small rocks, large bivalve shells and bottles. Twelve newly settled
recruits (<3 mm) were found: 11 on seagrass and one on hard substratum.
Settlement onto seagrass blades is the first field example of an abalone
species settling naturally onto soft substratum. 0+ recruits (4–9
mm) were found from March to October, indicating a single spawning and
settlement season. 0+ recruits were found on small isolated patches of
hard substratum in open and seagrass areas, suggesting that post-settlement
migration may have some influence on recruitment patterns. The results
indicate that the early life history of
Haliotis cyclobates is adapted for enhancing recruitment
into seagrass areas. Settlement onto seagrass blades is different from that
observed for other species of abalone, and clarification of the specific
settlement cue may contribute to the understanding of abalone settlement
behaviour.
Functional morphology of the mouthparts and alimentary tract of the slipper lobster Thenus orientalis (Decapoda : Scyllaridae)
Authors: Johnston Danielle J. , Alexander Christopher G.
Published: November 2005

The mouthparts and proventriculus of Thenus orientalis
Lund are adapted to ingest soft flesh, which is consistent with the diet of
this and other scyllarids. The crista dentata are reduced, with food transfer
into the oesophagus facilitated by large stout setae on the second and third
maxillipeds. The mandibles exert little force and most food maceration is
effected by the gastric mill. Ingestion is aided by mucus secreted by rosette
glands in the paragnaths and membranous lobe, as well as expansion of four
longitudinal folds in the oesophageal wall. The cardiac stomach has
considerable food storage capacity by extension of its membranous walls,
reduced ossicles and simplified ventral filtration channels. The filtering
ability of the pyloric filter press is consistent with other macrophagous
decapods. The dorsal caecum above the pyloric stomach has an absorptive
columnar epithelium that contains acid mucin granules and protein. Muscular
walls and longitudinal folds in the hindgut facilitate faecal pellet
extrusion.
Factors influencing the inorganic speciation of trace metal cations in fresh waters
Authors: Kim Jonathan P. , Hunter Keith A. , Reid Malcolm R.
Published: November 2005

The effects of pH and major ion composition on the chemical speciation of the
divalent cations of Co, Ni, Cu, Zn, Pb and Cd have been examined after
consideration of the available thermodynamic database for solution complexes
of these ions. Calculations were made for two model river waters representing
the 1% and 99% extremes in composition of global river waters.
The results show that inorganic speciation behaviour is of two characteristic
types: (a) Cu, Zn and Co are dominated by bis-hydroxy-
complexes at high pH and show the greatest reduction in the fraction of free
aquo ion with increasing pH; (b) Pb, Ni and Cd are
dominated by carbonato- complexes at high pH and show a more gradual decrease
in the fraction of free aquo ion with increasing pH. For Cu, Pb and Ni
significant fractions of the labile forms of these metal ions are present as
inorganic complexes in the pH range of most natural waters, whereas for Zn, Co
and Cd this is true only at moderately high pH (pH >7.5). Complexing with
the major ions SO42– and
Cl– is important only at low pH in river waters of
high ionic strength.
By-catch in the Patagonian red shrimp (Pleoticus muelleri) fishery
Authors: Pettovello Alejandro D.
Published: November 2005

This work recorded discards of by-catch (mainly Argentine hake
Merluccius hubbsi) from the Patagonian red shrimp
(Pleoticus muelleri) fishery in San Jorge Gulf,
Patagonia, Argentina, and evaluated the effectiveness of a shrimp-selectivity
device. By-catch species are listed, together with percentages of biomass per
species and frequencies of occurrences in tows. Biomass ratios of total by-
catch:shrimp and hake:shrimp caught were calculated by area and by season. In
experimental tows comparing the effects of grids in the codends of the nets,
two grids per codend (bar spacing 47 mm and 25 mm) excluded part of the
by-catch, but captures of shrimps were also lower than with a single grid (47
mm bar spacing) per codend.
Resumen. En el presente trabajo, se evalúa la
composición específica y la biomasa de fauna acompañante
de la pesca del langostino patagónico
Pleoticus muelleri del Golfo San Jorge (Patagonia,
Argentina). Los datos fueron obtenidos por medio de muestreos llevados a cabo
por observadores a bordo entre 1995 y 1997. Se presenta una lista de especies
acompañantes, junto con los porcentajes de biomasa por especie y
frecuencia de aparición en los lances. Para cada área y
estación se calcularon las tasas de fauna acompañante total y de
merluza común (Merluccius hubbsi) por kg de
langostino obtenido. La merluza común es la especie de mayor presencia
en los lances. Se efectuaron experimentos en base a modificaciones del arte de
pesca normal, comparándolo con el DISELA II (INIDEP), con dos grillas,
y con un arte de una sola grilla. El DISELA II excluye parte de la fauna
acompañante, pero afecta al volumen de langostino capturado. El arte de
una grilla excluye menos langostino, pero también menos fauna
acompañante.
Development of a numerical model of tidal and wind-driven circulation in Bass Strait
Authors: Fandry CB
Published: November 2005

The initial stages of the development of a numerical model to investigate the effects of wind and tidal forcing on the sea-surface height distribution and currents within Bass Strait are described. The hydrodynamical model is based on depth-averaged equations and incorporates the effects of the earth's rotation and variations in bottom topography. Numerical experiments have been performed with the model to determine the response of Bass Strait to two separate forcing mechanisms: stationary fields of uniform wind stress suddenly imposed over the sea surface, and tidal heights specified along the open-sea boundaries of the model. The results of these experiments are presented and discussed, the principal conclusions being that the maximum tidal currents generated are generally larger than those generated by the wind, and that variable bathymetry is a major influence on the flow. Furthermore the tidal motion may be characterized by two Kelvin waves travelling in opposite directions through the strait.
Mercury content of edible flesh from snapper, Chrysophrys auratus (Bloch & Schneider), in the Victorian commercial catch
Authors: Walker TI
Published: November 2005

The concentrations of total mercury (range 0.1-1.5 �g /g) in 40 individual snapper, C. auratus, caught in two commercial fishing areas in Victorian waters were adequately correlated with fork length by a power-law relationship. From further relationships established between length and total weight, and between filleted weight and total weight, the mean mercury concentration in the edible flesh of this species was estimated for each of the six years (1973-78) for which information on the length-frequency distribution was available for the Victorian commercial catch. The annual estimates ranged from 0.47 to 0.52 �g/g wet weight, and 45-52% of the edible flesh had values exceeding the Victorian statutory limit of 0.5 �g/g. Various management options available to health and fisheries agencies are discussed, and the methods of calculating the important parameters corresponding to these options are described. For example, graphs are presented from which can be read a legal maximum length of landed snapper, designed to reduce the mean mercury concentration of the catch to below a nominated level.
Distribution and significance of copper, lead, zinc and cadmium in the Corio Bay ecosystem
Authors: Smith JD , Butler ECV , Grant BR , Little GW , Millis N , Milne PJ
Published: November 2005

Levels of copper, lead, zinc and cadmium in sediments, waters and mussels (Mytilus edulis) from Corio Bay
(Vic.) were measured on two occasions in 1977. The bay has restricted water exchange with Port Phillip Bay
and is known to have received a major input of cadmium. The respective concentrations of copper, lead, zinc
and cadmium in the sediments were 2-50,2-2l0,4-398 and up to 12.6 �g/g; in the unfiltered waters, I .5-25,
<0.4-11, 3.9-67 and 0.11-5.6 �g/l; and in the mussels, 4.8-21. 1.2-9.7, 105-110 and 9.8-53 �g/g on a
dry weight basis.
The observed levels of heavy metals are compared with threshold levels reported in the literature as
causing significant interference with growth of phytoplankton and nutrient cycling by bacterial processes.
Ecological effects of mine effluents on the South Esk River, north-eastern Tasmania. II. Trace metals
Authors: Norris RH , Swain R , Lake PS
Published: November 2005

Concentrations of manganese, iron. cadmium, zinc, copper and lead in sediments and in the water column of the South Esk River, Tasmania, were measured. Manganese and iron concentrations were shown to be independent of the mine effluents. The natural background levels of cadmium. zinc, copper and lead were found to be very low or below detection limits. In the stretch of river up to 130 km below a source of contamination, the concentrations of these four metals in the sediments, associated with the non-filterable residue, and in solution were all well above the natural background leveis. The facrors controlling the concentrations of cadmium, zinc, copper and lead in the sediments are not clear; however, sediment type appears to be important. The concentrations of cadmium and zinc in solution were inversely related to the distance from the source ofcontamination, whereas the concentrations of copper and lead in solution and of all four metals associated with the non-filterable residue did not vary significantly. Most of the metal-load carried to the South Esk River by Storys Creek is probably in solution rather than in other fractions.
Life histories of benthic invertebrates in a kauri forst stream in northern New Zealand
Authors: Towns DR
Published: November 2005

Life histories of the following 12 benthic invertebrate species were investigated at four sites in the Waitakere River: Potamopyrgus antipodarum (Gastropoda : Hydrobiidae); Paracalliope fluviatilis (Amphipoda : Eusiridae), Zephlebia (Neozephlebia) sp. and Deleatidium spp. (Ephemeroptera : Leptophlebiidae), Hydora nitida (Coleoptera : Elmidae), Maoridiamesa harrisi, ?Austrocladius sp. and Paratanytarsus agameta (Diptera : Chironomidae), Austrosimulium australense (Diptera : Simuliidae), Aoteapsyche colonica (Trichoptera : Hydropsychidae), Oxyethira albireps (Trichoptera : Hydroptilidae), and Olinga feredayi (Trichoptera : Conoesucidae). All species had life cycles which were non-seasonal according to the Hynes model. Comparison with recent studies in southern North Island and South Island streams suggests that non-seasonal life cycles predominate in New Zealand streams.
Use of catchability equations for population estimation of marron, Cherax tenuimanus (Smith) (Decapoda : Parastacidae)
Authors: Morrissy NM , Caputi N
Published: November 2005

Marron in a 0 .01-ha hatchery pond were sampled after sunset on 14 occasions over 2 years in a standardized manner using baited drop nets. An inventory of the total population was taken after each sampling by draining the pond. Variation in catchability. p, was analysed by linear logit models of p/(1 - p) using the likelihood ratio χ2- statistic G2 as a measure of goodness of fit. A reduction in G2 of 83% was produced by inclusion of water temperature. T� (C); relative position of marron in the size distribution, S (rather than absolute size); and a between-years factor, Y. The following catchability equation was calculated:

In[pI/(l-pI)] = -5.40 +0.523S-0.246S2 +0.220T+1.40Y.

The catchability equation was then applied to drop-net catch numbers from stocks of marron of 2-2+ years old in 10 0.1-ha farm dams. Estimated cohort numbers were compared with 'true' values obtained by independent removal of the stocks by seining. Agreement was improved by adjusting these estimates for differences in Secchi disk values, D. between dams (because daytime sampling was pursued and illuminance markedly influences catch rates) and in coefficient of size variation, V, The latter was negatively correlated with catchability and appeared to reflect the intensity of size dominance in feeding competition. A catchability equation. including these additional factors, was calculated:

In[pI/(l -pI)] = -0.081 +0.664S -0.214S2 +0,284T -0.668ln D - 19.5V.

Compared with other methods of estimation in which equal catchability is assumed, this method takes into consideration variation in catchability, requires no marking of individuals, and needs only one sampling occasion to obtain an estimate of crayfish numbers. Because of dependence of catchability on size of marron, sample means over estimated mean individual body weight by 13-48%. The catchability equation was also used to correct for this bias.
Biomass method for measuring productivity of Echlonia radiata, with the potential for adaptation to other large brown algae
Authors: Mann EH , Kirkman H
Published: November 2005

A solution is proposed to the problem of converting measurements of growth in length of E. radiata to estimates of biomass production. It is shown that production can be calculated by multiplying biomass per unit length (in the zone of maximum biomass) by the increase in length of the primary blade. E. radiata has three stages of growth: (i) a simple strap-shaped primary blade; (ii) secondary blades growing from the primary; (iii) tertiaries arising from the secondaries in the mature plant. Distribution of biomass was determined by making transverse cuts across the primary blade and weighing the segments together with all attached secondary and tertiary blades. Plants were divisible into a zone where secondaries and tertiaries were increasing in size, a zone where they were at maximum size, and a zone where they were eroding. Biomass per unit length was calculated for the zone of maximum biomass, and when multiplied by the growth in length gave a good estimate of biomass production. Adaptation of this method to other large brown algae of the Laminariales is proposed.
Physical properties of Great Barrier Reef lagoon waters near Townsville. I. Effects of Burdekin River floods
Authors: Wolanski E , Jones M
Published: November 2005

Floods from land runoff, principally the Burdekin River. created buoyant freshwater plumes along the coast of the Great Barrier Reef lagoon. From Cape Upstart near the Burdekin River mouth to Innisfail 250 km north. no evidence was found of these plumes directly reaching the Great Barrier Reef. Small buoyant patches, detached from the river plumes, found further offshore might reach the Great Barrier Reef. Classical estuarine circulation in the lagoon. even in flood conditions, and tidal flushing by the ocean do not appear to be significant compared to advective processes.
Nature and hydrocarbon content of blooms of the alga Botryococcus braunii occuring in Australian freshwater lakes
Authors: Wake LV , Hillen LW
Published: November 2005

Under Australian conditions blooms of B. braunii were found to have hydrocarbon oil contents between 27 and 40% of the dry mass. The highest oil content was observed in a red bloom and the lowest in a green bloom of the organism. A number of branched-chain hydrocarbons of the general formula Cm H2n-10. where n equals 30. 34. 35. 36 and 37, have been found in both red and green blooms of the alga. Twelve of these hydrocarbons are novel to the present study and analysis by gas chromatography-mass spectrometry indicates that these compounds are closely related to or isomeric with botryococcene. Straight-chain hydrocarbons were present only in the green stage of the organism. Evidence for the simultaneous occurrence of branched- and linear-chain hydrocarbons in the same plant is inconclusive as blooms which revealed both types of hydrocarbons were known to contain both stages of the alga. The chemical parameters measured, both of the cell material and of the waters in which they grow, have thus far failed to explain why conditions are sometimes more favourable to the formation of B. braunii blooms than at other times. B. braunii has been observed to form shoreline deposits which undergo a change in pigmentation during desiccation to produce a black rubbery material bearing a strong resemblance to Coorongite. A detailed comparison has yet to be undertaken.
Behaviour of the Western Australian spiny lobster, Panulirus cygnus George, in the field and laboratory
Authors: Cobb JS
Published: November 2005

The behaviour of the spiny lobster, Panulirus cygnus, of Western Australia was studied in the laboratory and field. A brief description of behavioural units is provided. A den residency survey showed only 3% of the lobsters sheltered singly, and the number of lobsters in a single den ranged from 1 to more than 100. Lobsters left dens in the evening and returned in the morning, following specific pathways along the reef face, implying knowledge of the local topography. The lobsters returned to the same area of the reef but not necessarily the same den after foraging. The occupancy of any particular den remained fairly constant over a period of time but changed markedly after a storm. The reactions of lobsters to a predator (Octopus tetricus) released at the mouth of a den were high alert postures, antennae pointing and waving, and slow retreat from the den. In a large laboratory pool, stridulation and tail flip were frequent when an octopus was out of its lair and moving around.
Estimation of the spawning stock biomass of blue grenadier (Macruronus novaezelandiae) off western Tasmania based upon the annual egg production method
Authors: Bulman C. M. , Koslow J. A. , Haskard K. A.
Published: November 2005

Egg production of the blue grenadier,
Macruronus novaezelandiae, spawning stock off western
Tasmania was surveyed from June through September in 1994 and 1995. In each
year, daily egg production rates were calculated for each of three surveys and
a normal curve was fitted to estimate annual egg production. The CV for the
egg production estimate for the survey at the peak of the 1995 season was
14%. Daily egg mortality was not significant in any survey, but a value
of 5% was assumed. The spawning biomass of blue grenadier on the west
coast of Tasmania was estimated to be between 83 660 and 100 073 t in 1994 and
between 59 727 and 71 376 t in 1995. Confidence limits of the estimates were
obtained by a bootstrap where the highly skewed egg density data were
resampled. Biomass was approximately inversely proportional to incubation
time. Increases or decreases in mortality resulted in slightly smaller
increases or decreases of biomass respectively. Uncertainty of the sex ratio
between spawning and non-spawning periods caused the largest variation in
biomass estimate (~30%). The proportion of the population that spawns
each year remains a further uncertainty in the estimate of total stock
biomass.
Growth of Pacific oysters, Crassostrea gigas Thunberg, cultivated in Tasmania. II. Subtidal culture
Authors: Sumner CE
Published: November 2005

Pacific oysters cultured subtidally grew faster than intertidal oysters, both in the catching zone of the River Tamar and at the growing lease. Three months after settlement in the Tamar River, mean length of subtidal oysters was 24.4 mm and mean width was 18.6 mm. Oyster spat transferred to a growing lease at Dover increased in mean length from 21.7 to 109.0 mm in 14 months while mean width increased from 13.5 to 76.1 mm. Seasonal differences in growth were not as marked as for intertidal oysters and were similar for both length and width. Significant differences in lengths were noted for position on the longline, with largest individuals on rens closest to the middle of the stream (north). To a lesser extent mean lengths also varied with depth: oysters growing at 3-6 m were significantly larger than other groups. Live weights of oysters at 12 and 17 months were 69.5 and 106.7 g and drained flesh weights were 18.3 and 25.5 g respectively.
Description, distribution and abundance of late larval stages of the Scyllaridae (slipper lobsters) in the south-eastern Indian Ocean
Authors: Phillips BF , Brown PA , Rimmer DW , Braine SJ
Published: November 2005

Plankton samples from the south-eastern Indian Ocean between 25�30's. and 35�00'S. and from the Western Australian coast out to 99� 00'E., showed the presence of several species in three genera of the Scyllaridae; Scyllarides sp. a; Scyllarus demani; Scyllarus bicuspidatus; Scyllarus spp. a, b, and c; Ibacus peronii and Ibacus sp, a. The final (gilled) phyllosoma and nisto stages of previously undescribed species are described. A generic key to the final phyllosoma of the Palinuridae, Scyllaridae and Synaxidae recorded from the southern Indian Ocean is presented. The distribution of the catches of the phyllosoma of Scyllarus bicuspidatus, Scyllarus sp. b, Ibacus peronii and Scyllarides sp. a and data on the seasonal catches of all scyllarid species are presented. The phyllosoma of S. bicuspidatus undergo diel migrations. Early-stage densities peak at depths of 40-80 m during the day, and mid and late stages peak at 80-100 m. At night the early stages are found at the surface, independent of moonlight intensity. Mid and late stages peak at the surface only on moonless nights. On moonlit nights the density of mid and late stages peak at 15-25 m depth.
Saccocirridae (Annelida : Archiannelida) from the central coast of New South Wales
Authors: Brown R
Published: November 2005

Saccocirrids (archiannelids) were collected from coarse-grained sediments in turbulent water from the central New South Wales coast. Saccocirrus jouinae, sp. nov., and S. tridentiger, sp, nov., are described, and S. krusadensis Alikunhi, 1948 newly recorded in Australia. In these species gonads occur only on the left side of the body and cilia are found on the ventral surface. Of the 17 species attributed to the Saccocirridae, seven species are known to have unilateral gonads and ventral ciliation. They occur only in the Indo-Pacific region. Species with gonads on both sides of the body have not been described with cilia on the ventral surface. Their distribution is world-wide.
Relationship between some environmental parameters and trypanorhynch cestode loads in banana prawns (Penaeus merguiensis de Man)
Authors: Owens L
Published: November 2005

The population of P. merguiensis in the Norman River was sampled at weekly intervals for 6 months during the 1978-79 summer. The size-frequency distribution of one recruitment cohort to that river was progressively studied. and individual prawns examined for parasites as they grew from post-larvae to adolescence. The juvenile banana prawns were essentially unparasitized by pierocerci of Parachristianella monomegacantha Kruse until they reached 13 mm carapace length. Thereafter. the larger adolescent prawns accumulated trypanorhynch parasites in proportion to their increases in size. This was attributed to a change in feeding habits at 13 mm carapace length. Previous studies had shown that, at least on spring tides, juvenile banana prawns fed in the lower littoral zone at low tide. and adolescent prawns were more conspicuous at high tide when waters entered the mangrove areas. These studies, coupled with the above data, suggested that the main infective area for the prawns was mangroves in the upper littoral zone. When marine salinities increased from 32 to 37‰ prevalence of Paiachristianella monomegacantha also rose. Estuarine salinities of 12-32‰, had no appreciable effect on parasitism, with the level being low and constant throughout this range. This result was possibly due to differential survival of infective stages in the estuary. As a corollary to this. the percentage of infected Penaeus merguiensis dropped from a maximum of 84% at the mouth to 26% at Normanton, 80 km upstream. When considering the use of parasites as biological tags for the estuarine phase of catadromous penaeid prawns, the size of the prawns and salinity where they are captured have substantial effects on parasite loads.