bluuebunny/crossref_metadata_2025 huggingface dataset:
Biochemical systematics of the marine fish family Centrolophidae (Teleostei:Stromateoidei) from Australian waters
Authors: Bolch CJS , Ward RD , Last PR
Published: November 2005

The phylogenetic relationships of 11 stromateoid species (nine from the Family Centrolophidae and one
each from the Nomeidae and Tetragonuridae) were examined by allozyme electrophoresis. Data from 30
loci were used for three phylogenetic analyses. Two phenetic trees were derived: a UPGMA tree derived
from Nei's unbiased genetic distance, and a distance-Wagner tree based on modified Rogers' distances.
A cladistic analysis, using maximum parsimony, was also carried out with loci as characters and alleles as
unordered states.
The tree topology of all three analyses showed a high degree of similarity, which increased confidence
in the phylogenetic interpretation and generally supported the classical taxonomic theory of centrolophid
relationships. The 'hard-spined' centrolophid taxa, including Seriolella, Psenopsis, Schedophilus
labyrinthicus and Hyperoglyphe, formed a stable group In all trees. Psenopsis was closely allied to
Seriolella in all three analyses, which supports the view that this genus is derived from Seriolella.
Centrolophus and Tubbia consistently diverged from the ancestral line of taxa near the base of the tree, so
may have diverged from ancestral stock earlier than previously thought. The most striking departure from
current taxonomic theory was the wide separation of Schedophilus labyrinthicus and Schedophilus
huttoni, indicating that the genus Schedophilus is polyphyletic. A revision of the genus is needed and
should include morphological and electrophoretic analyses of all Schedophilus species, with particular
reference to the type species S. medusophagus.
Reproductive biology and pathological changes of the Egyptian sole (Solea aegyptiaca, Chabanaud, 1927) from polluted waters of Abu-Kir Bay near Alexandria, Egypt
Authors: Abdel-Aziz SH
Published: November 2005

Solea aegyptiaca in Abu-Kir Bay becomes mature at 18 and 20 cm total length for males and
females respectively and within two years of age for both sexes. Spawning occurs in winter
(December-February). The sizefrequency distribution of oocytes more than 100 pm in diameter
indicates that S. aegyptiaca is a determinate spawner and that an annual potential fecundity can
be measured. Low gonadosomatic index and low potential fecundity, low condition factor (K),
and histological anomalies of the ovaries of some mature females have been observed during
the reproductive period. The presence of pollutants in Abu-Kir Bay sediments resulting from
industrial wastes and untreated sewage may be responsible for this alteration in oogenesis and
the consequent drop in fecundity.
Limnological features of lakes on the Sepik-Ramu floodplain, Papua New Guinea
Authors: Vyverman W
Published: November 2005

The Sepik-Ramu floodplain is one of the major wetland areas in south-eastem Asia. This paper reports
preliminary limnological data on 26 lakes on the lower and middle reaches of the floodplain. Conductivity,
pH and alkalinity increase from upstream lakes to downstream lakes. A first attempt is made to classify the
lakes according to water colour and sediment load, as indicators of local hydrology. Humic-stained black
waters can be distinguished from sediment-loaded white waters as well as from a number of transitional
mixed waters. All the lakes studied had very shallow optical depths (Secchi depths between 0.25 and 1.84 m),
owing to either high gilvin concentrations or turbidity. Extinction coefficients for downward irradiance,
measured in three lakes, were higher in surface water layers (Kd = 3.4 - 19.5 m-1) than in deeper layers
(Kd = 2.5 - 11.0 m-1). The data suggest that the lakes represent a range of stratification regimes, from nonstratified
lakes to lakes stratified over prolonged periods. Local hydrology, basin morphometry and local
topography seem to be the major factors controlling stratification regime. Phytoplankton biomass was
lowest in black-water lakes (2.3 × 105 �m3 mL-1), and high values (1.7 × 108 �m3 mL-1) were recorded
in white-water and stratified mixed-water lakes. The preliminary data suggest that there may be
considerable seasonal fluctuation of phytoplankton biomass.
Trace metals as tracers of dredging activity in Cleveland Bay — field and laboratory studies
Authors: Reichelt AJ , Jones GB
Published: November 2005

This study has investigated in detail trace metal concentrations in Cleveland Bay in the central
Great Barrier Reef and assessed the significant carrier phases of several metals during a simulated
disturbance of sediments designed to investigate the effects of dredging. Organic, iron oxide
and carbonate phases were shown to be important carrier phases for several trace metals. The
application of an acid-leach technique to monitor labile or pollutant concentrations of copper,
zinc, lead and nickel in sediments collected from coral reefs sampled before and after two
dredging events in 1991 yielded useful information on the fate of dredged sediment. Trace metal
contamination close inshore was attributed to port activities, sewage discharge and urbanization.
Predation on soft corals (Octocorallia: Alcyonacea) on the Great Barrier Reef, Australia
Authors: Griffith JK
Published: November 2005

Quantitative evidence on predation rates on soft corals is presented for the first time. These measured
predation rates were low. Less than 1% of the soft coral colonies present in mapped areas at Heron Island
and Beaver Reefs had bite marks. Evidence suggests that over 51% of these bite marks were more than two
months old. Predators included the mollusc Ovula ovum and two species of chaetodontid fishes that have
not been recorded before as feeding on soft corals.
Are outbreaks of Marteilia sydneyi in Sydney rock oysters, Saccostrea commercialis, triggered by a drop in environmental pH?
Authors: Anderson TJ , Wesche S , Lester RJG
Published: November 2005

Two outbreaks of Marteilia sydneyi in oysters near the mouth of the Brisbane River are described.
Before the first outbreak the pH fell slightly, but before the second outbreak it remained unchanged.
Changes in salinity and temperature were minor. The results indicate that these epizootics of
M. sydneyi were not correlated with fluctuations in pH, salinity and temperature of water in close
proximity to the oysters.
Plants and processes in wetlands: A background
Authors: Boon PI , Brock MA
Published: November 2005

It is easy to gain an impression from the recent contents of Australian scientific journals dealing with
ecological research that little attention is paid to the botanical ecology of Australia's inland wetlands. Less
than 1% of the papers published in key Australian ecological journals over 1987-93 dealt with some aspect
of the vegetation ecology of these environments. Yet over the period 1982-94 research on this topic
accounted for up to 23% of the papers presented at annual conferences of the two major Australian
scientific societies to which Australian limnologists are likely to belong. This discrepancy indicates that
wetland vegetation is the subject of a considerable research effort by Australian limnologists, but that few
of their research findings are published in refereed Australian journals. Analyses of the references cited in
key review articles suggests that refereed journals outside Australia cannot account fully for the 'missing'
publications: we demonstrate that much research is placed in the largely inaccessible 'grey literature'
published by government departments and the like. It is also possible that some research is destined never
to be published. This imbalance between the intensity of the research effort and the history of publication in
Australian refereed journals prompted local scientists involved in wetland research to participate in a
Special Issue dedicated to the botanical and process-oriented aspects of wetland ecology.
Effects of grazing and depth on two wetland plant species
Authors: Blanch SJ , Brock MA
Published: November 2005

Wetland plants in Llangothlin Lagoon, northern New South Wales, are subject to grazing and trampling by
cattle, sheep and waterbirds and to fluctuating water levels. Myriophyllum variifolium J. Hooker, an aquatic
dicotyledon with dispersed meristems, exhibited different morphological changes to the emergent
monocotyledon Eleocharis acuta R. Br, under simulated and natural grazing at different water depths.
Responses were principally determined by position and number of meristems.
Growth point production (numbers of shoots and branches) increased under light, frequent clipping
(25% every 14 or 7 days) in non-submerged plants only. Node production, total plant or shoot length, and
above- and below-ground biomass decreased under similar clipping treatments. E. acuta did not increase
shoot production or above-ground biomass under any clipping treatment, and only for the lightest clipping
treatment (clipped once to 7 cm when non-submerged) was no decrease in total shoot length observed.
More intense and frequent clipping treatments and submersion to 15 cm prevented both species from
replacing lost tissues. Interaction between clipping and submersion occurred in both species, indicating that
growth responses are complex.
The distribution and abundance of the two species reflect the greater tolerance of M. variifolium than
E. acuta to grazing and inundation. Low intensities of cattle and sheep grazing may be beneficial by
increasing species diversity.
Effects of water-level changes induced by weirs on the distribution of littoral plants along the River Murray, South Australia
Authors: Walker KF , Boulton AJ , Thomas MC , Sheldon F
Published: November 2005

In 1988 a survey was made of the River Murray between Locks 2 and 4 (153 river-km) to determine
whether the distributions and relative abundances of littoral plants are influenced by water-level variations
associated with weir operations. Of 20 recorded plant species, some, including Cyperus sp, and
Myriophyllum verrucosue, occurred in regions downstream of each weir and hence were exposed to
maximal variation in river levels. Others, notably Typha spp., favoured the regions above each weir, where
levels are comparatively stable. The influences of physical channel characteristics such as bank slope, bank
erosion and sediment composition and of other environmental factors were not clear. These effects may
have been obscured by differences in the natures of the two pools and by a tendency for factors correlated
with the water-level gradients to be 'reset' at each weir. Changes in the flow behaviour of the river since
1990 suggest that these survey data may later prove useful in evaluating the effects of high turbidities
associated with regulated flows from the Darling River.
Reliance of creek-side river red gums on creek water
Authors: Thorburn PJ , Mensforth LJ , Walker GR
Published: November 2005

Measurements of naturally occurring stable isotopes of hydrogen (2H) and oxygen (18O) were used to
determine the importance of creek waters to river red gums (Eucalyptus camaldulensis Dehnh., Myrtaceae)
on the banks of creeks in the semi-arid and saline Chowilla floodplain region of South Australia. The 2H
and 18O concentrations of water sampled from trees were significantly different from those of the creek
water, indicating that, generally, trees were not obtaining all their water from the creek. This was found
even in trees overlying highly saline groundwater. Thus, saline groundwater and/or soil water were
important water sources for the trees studied. The results indicated that the water relations of these trees are
complex, and the trees may be less affected by changes in creek flow and/or salinity than was previously
anticipated.
Seasonal germination from wetland seed banks
Authors: Britton DL , Brock MA
Published: November 2005

Seasonal germination from the seed banks of five wetlands that experience unpredictable fluctuations in
water level was examined by wetting dried sediments at three-monthly intervals over a 14-month penod.
Germination trials were conducted both outdoors and in an unheated, naturally lit glasshouse. In each trial,
sediments were maintained in a waterlogged condition for eight weeks, after which all germinating
individuals were counted and identified. Although germination occurred in all seasons at all sites, both
numbers of species and numbers of individuals germinating from the wetted sediments were significantly
affected by season, both outdoors and in the glasshouse. In the outdoor trials, greatest numbers of
individuals and species generally appeared in autumn, fewest in summer. Sensitivity to a combination of
high maximum and high mlnimum temperatures may have evolved in wetland species of the area as a
mechanism ensuring that germination is dramatically reduced in summer, when conditions for
establishment of young seedlings may be particularly unfavourable.
Water depth changes and biomass allocation in two contrasting macrophytes
Authors: Rea N , Ganf GG
Published: November 2005

The response of B. arthrophylla and T. procerum in pot experiments to depth and depth changes provided
insight into how plants survive fluctuating water levels. At 0 cm depth, most biomass was placed below
ground, which can be interpreted as the placement of resource-acquiring tissues (roots, rhizomes) in
resource (nutrients, space) -supplying environments. At 50 and 100 cm, the placement of biomass into
shoots recognized the need for a higher supply of above-ground resources (light, inorganic carbon, oxygen).
However, the responses of the two species to flooding or exposure differed. Rhizome storage supported an
increase in the number and height of B. arthrophylla stems when flooded by 50 cm but this species was
unable to counteract submergence to 100 cm without the critical loss of root mass. The slow turnover rate
of the cuticularized B. arthrophylla stems indicates that biomass needs to be allocated above water as well
as above ground. Other responses indicated that this species may be better suited to seasonally fluctuating
rather than permanent water levels. T. procerum dealt with water level changes via morphological
plasticity. Along with the rapid growth and turnover of the spongy leaves, its shoot and total mass were
maintained primarily from resources in the tubers.
The role of sexual reproduction and water regime in shaping the distribution patterns of clonal emergent aquatic plants
Authors: Rea N , Ganf GG
Published: November 2005

The reproductive characteristics of T. procerum in three lagoons in the Mediterranean south-east of South
Australia were used to investigate the role of water regime in the often heterogeneous and patchy
distribution of aquatic vegetation. A theoretical explanation for these patterns, based on sexual reproduction
vis-a-vis seedling establishment, is proposed. Owing to the unpredictable nature of seed dispersal and the
narrow range of suitable conditions for germination and establishment that result from fluctuating and
variable water levels, establishment events are spatially and temporally dynamic. These features may be
important for maintaining species distribution, species survival and habitat diversity. Population resilience
through genetically heterogeneous stands is another outcome. The implications of sexual reproduction by
clonal plants are discussed, as is the need to maintain the conditions that plants need to flower, germinate
and become established. The unpredictable nature of establishment events makes them difficult to manage.
Regulation and pondageldrainage may be having a profound effect on the survival of many aquatic plant
species owing to their inability to regenerate under such conditions.
Distribution, productivity and reproductive phenology of emergent macrophytes in relation to water regimes at wetlands of south-western Australia
Authors: Froend RH , McComb AJ
Published: November 2005

Variability in the response of Baumea articulata and Typha orientalis to water regime was assessed at eight
urban wetland lakes on the Swan Coastal Plain, south-western Australia. Distribution, productivity and
reproduction along water regime gradients were assessed, and the importance of wetland nutrient status in
altering plant response to water regime was also considered.
The overall range in distribution observed across the lakes was similar for both species, but there was
significant between-lake variation in distribution relative to mean water depth. Neither species occupied its
full 'potential' distribution range, relative to water regime, at any one wetland. Standing biomass and ramet
and inflorescence densities varied along the water regime gradient, with peak values generally occurring at
intermediate water depths. There was a shift in phenology (ramet emergence, new leaf growth, flowering
and seed production) with increasing mean water depth and nutrient status. Seasonal values of aboveground
productivity changed along the water regime gradient for both species. Comparison of productivity
at sampling points of different nutrlent status but similar water regime showed a significantly greater
growth response in T. orientalis compared with B. articulata. The significance of these results to urban
wetland management is discussed.
Airspace structure and mathematical modelling of oxygen diffusion, aeration and anoxia in Eleocharis sphacelata R. Br. Roots
Authors: Sorrell BK
Published: November 2005

A quantitative description of the structure of the roots of Eleocharis sphacelata is presented, forming the
basis of a mathematical analysis of their aeration via the intercellular airspace system. The mature
aerenchymatous roots have cortical porosites as high as 70% and resistances to axial diffusion of
0.015-0.04 Ms mm-3 per mm root length. The corresponding resistance in the younger,
non-aerenchymatous tissue just behind the apex is 0.08-0.14 Ms mm-3 per mm, root length. The
observed maximum length of the roots (about 0.3 m) is not caused by the oxygen limitations at the apical
meristem of the main axis because axial fluxes could theoretically support the meristem in much longer
roots. However, the phloem and pericycle of the stele become hypoxic at 0.25 to 0.3 m, suggesting that
length could be limited by the need to prevent excessive hypoxia in these tissues. Rates of root oxygen
release into the sediment are predicted to be as high as 2.5 �mol h-1 per 0.3-m-long root and higher still
for shorter roots. The prevention of anoxia depends greatly on the basal oxygen concentration at the root
base: oxygen partial pressures below 8 kPa in the rhizome would cause meristematic anoxia in 0.3 m-long
roots. A better resolution of fine-scale variations in respiratory activity in the roots and in the sediment
rhizosphere could improve the accuracy of the model, but it does nevertheless indicate that roots of
E. sphacelata would normally remain aerobic and significantly oxidize anaerobic sediments in situ.
Methane flux from beds of Baumea arthrophylla (Nees) Boeckeler and Triglochin procerum R. Br. at Bool Lagoon, South Australia
Authors: Muller KL , Ganf GG , Boon PI
Published: November 2005

The flux of methane from freshwater wetlands is likely to be influenced by the presence of emergent
macrophytes. The plants generate an organic loading, which should increase methanogenesis, yet they also
aerate the sediment, creating oxic zones inimical to the obligately anaerobic methanogenic bacteria and
promoting the oxidation of methane by methanotrophic bacteria. Moreover, emergent plants can act as a
conduit for methane to be vented to the atmosphere. Depth profiles of oxygen in beds of B. arthrophylla
and T. procerum at Bool Lagoon, South Australia, showed that water at the sediment surface was anoxic
during the night but became oxygenated during the latter part of the day. Redox profiles of the sediment
gave values that ranged from -50 to +250 mV, indicating a sediment that was not highly reducing. Despite
these conditions, the wetlands were sources of significant methane emissions, with total water-atmosphere
fluxes ranging from < 0.0 t1o 1.05 mmol m-2 h-1. The presence of B. arthrophylla, but not that of
T. procerum, affected the bubble concentration of methane in the sediments. Diel variations in ebullitive or
total methane fluxes were not detected, but emissions varied according to water depth and time of year.
Treatments that removed macrophytes reduced total methane fluxes to rates approximately equivalent to
ebullition, indicating that the plants were acting as a major pathway for the release of methane to the
atmosphere. The lack of a clear die1 pattern in emissions suggests that diffusion, rather than convective
flow, is the mechanism for this flux through the plants.
Reactive silicate in shelf waters near Otago Peninsula, New Zealand
Authors: Hawke DJ
Published: November 2005

Reactive Si data from 19 monthly occupations of two transects near Otago Peninsula in 1986-87 showed low surface values (≤1 μM) during spring and summer, and high values (>4 μM) in winter. Concentrations were greatest after flooding in the Clutha River, 100 km south of the study area. In spring and early summer, concentrations were lowest inshore at the surface. At other times of the year, concentrations were highest in inshore surface waters, and usually coincided with the salinity minimum. Vertical gradients across the Southland Front, a near-horizontal thermal front outcropping near the shelf break, were calculated and compared with phosphorus gradients from the same samples. Nine of 21 Si gradients were negative (i.e. concentrations decreased with depth), whereas only 1 of 24 phosphorus gradients was negative. This implies that riverine Si flux is important in establishing Si gradients across the Southland Front. The results are a further indication of the importance of the Clutha River to the Otago shelf system.
Effect of experimental conditions on phosphorus extracted from estuarine and marine sediments
Authors: Pailles C , Moody PW
Published: November 2005

The effect of the ratio of sediment to extracting solution was determined on the amount of P extracted by the Bray-P1 extractant (0.03 M NH4F in 0.025 M HCl) from 10 estuarine and marine sediments. Phosphorus extracted from the sediments by the Colwell extractant (0.5 M NaHCO3 at pH 8.5) was also determined. Decreasing the ratio of sediment to Bray-P1 extractant from 1 :7 to 1 : 7000 caused a one-hundredfold increase in extractable P. The amount of Bray-P1 extractable P also decreased significantly (P < 0.001) as extraction pH increased, and extraction pH varied between sediments. Sediment CaCO3 content alone could not explain the increase in extracting solution pH (i.e. neutralization of the acid in the extracting solution) that occurred during the extraction period, and the surface area of the CaCO3 may be a factor in determining final extraction pH. Bray-P1 extractable P was not correlated with Colwell extractable P.
Because of the effect of the sediments on Bray extractant pH, it is concluded that this extractant is inappropriate for determining the P status of estuarine and marine sediments. The effect of the ratio of sediment to extracting solution on extractable P has implications for determining the P status of suspended sediments.

Extra keywords: Bray extractable P, Colwell extractable P
Absence of regulated blood-oxygen transport in response to strenuous exercise by the shovelnosed ray, Rhinobatos typus
Authors: Lowe TE , Wells RMG , Baldwin J
Published: November 2005

Haematological indices and the erythrocyte nucleotides ATP and GTP remained unchanged following strenuous exercise. These data suggest that neither increased oxygen-carrying capacity nor modulated haemoglobin-oxygen affinity are available to assist oxygen debt recovery after exercise. Marked increases in plasma lactate pointed to a post-exercise metabolic acidosis. Concentrations of adrenaline and noradrenaline increased sharply after strenuous exercise, with adrenaline the dominant catecholamine. These endocrine responses were not coupled to plasma lactate, and did not result in erythrocyte swelling. The constancy of the plasma ions Na+ and Cl- suggests that branchial ion- exchange mechanisms remained patent, but a rise in K+ was consistent with leakage from the myotomal mass. These responses suggest that the ability of the rhinobatoid ray to resume aerobic activity following burst exercise is severely limited.
Effects of gonadal steroids and human chorionic gonadotrophin on final oocyte maturation in vitro in the New Zealand snapper Pagrus auratus (Sparidae)
Authors: Ventling AR , Pankhurst NW
Published: November 2005

This study investigated the role of steroids and gonadotrophin in final oocyte maturation (FOM) in the New Zealand snapper (Pagrus auratus) by means of in vitro techniques. Ovarian fragments containing vitellogenic oocytes were incubated for up to 48 h with a range of doses of gonadal steroids andlor human chorionic gonadotrophin (hCG). The ability of ovarian tissue to synthesize putative maturational steroids was assessed by measuring production of 17α,20β-dihydroxy-4-pregnen- 3-one (17,20βP) by ovarian fragments incubated with hCG and 17α-hydroxyprogesterone (17P). 17,20βP was consistently the most effective maturational steroid, inducing FOM at doses as low as 1 ng mI-1. The next most potent steroids were 20β-hydroxylated progestins and 17P, which were effective at relatively high doses (100 ng mI-1) only. The single androgen tested (testosterone) was least effective at inducing FOM. Oocytes were less responsive to hCG alone than to steroids, but the combination of hCG and steroids enhanced responsiveness in some incubations. Oocytes produced 17,20βP in response to treatment with 17P, and the response was augmented by co-treatment with hCG. HCG alone was ineffective at stimulating production of 17,20βP. The results of this study are consistent with reports that 17,20βP is generally the most potent steroid for the induction of FOM in teleosts.
Early development of the Australian crimson-spotted rainbowfish, Melanotaenia fluviatilis (Pisces: Melanotaeniidae)
Authors: Reid HP , Holdway DA
Published: November 2005

This paper describes the early ontogeny of the crimson-spotted rainbowfish Melanotaenia fluviatilis. Eggs ranged in size from 0.98 to 1.07 mm and 35-45 oil droplets were present, as were numerous adhesive filaments which originated from one point. Hatching was predominantly 7-9 days after spawning at 25.5�C. At hatching, larvae (4.2 mm standard length) had a reduced but still present yolk sac and were strong enough swimmers to remain in the upper 1 cm water layer. The swim bladder inflated within 10 h of hatching and the first ingested food was observed after 12 h. At 32 days after hatching, the mean larval length was 13.86 rnm and at 72 days was 21 mm. Knowledge of the critical developmental stages described in the paper is important in understanding the impact of the major biotic modifying factors influencing the impact of chemicals and other pollutants on rainbowfish, especially given that they are used by ecotoxicologists as a surrogate species for Australian freshwater fish in general.
Different patterns of resource use between two coexisting freshwater calanoid species
Authors: Kobayashi T
Published: November 2005

Patterns of resource use (i.e. dietary richness, breadth and overlap) for the coexisting but differently sized species Calamoecia lucasi and Boeckella minuta were examined in specimens collected from Wallerawang Reservoir between April 1986 and September 1987. Significant differences in the dietary richness and dietary breadth were found between the species. Dietary overlap, as measured by Schoener's index, fluctuated within a relatively low range throughout the time interval. The effective resource partitioning may account for the perennial coexistence of these species. Since the degree of resource overlap cannot be directly related to the extent of competition, further experimental studies are necessary to determine how important the resource partitioning is in processes structuring associations of calanoid species.
Influence of sample quantification and taxonomic resolution on the ordination of macroinvertebrate communities from running waters in Victoria, Australia
Authors: Marchant R , Barmuta LA , Chessman BC
Published: November 2005

The influence of sample quantification and taxonomic resolution on the ordination of macroinvertebrate communities from nine Victorian rivers was examined by progressively reducing the degree of detail in the original data (species level, quantitative). Five additional data sets were created that consisted of binary (presence or absence) data on species, quantitative or binary data on families, and quantitative data on PET (plecopteran, ephemeropteran and trichopteran) species or families. Ordinations were performed with detrended correspondence analysis (DCA) and semi-strong hybrid multi-dimensional scaling (SSH). With both ordination techniques, the ordinations of each data set (including the original) revealed the same three underlying gradients. An altitudinal gradient consistently achieved the highest correlations with the ordinations (r = 0.71-0.93), followed by a substratum gradient (r = 0.50-0.88) and a combined pH and conductivity gradient (r = 0.47-0.76). Each of the five less-complete data sets thus provides an adequate degree of detail for ordination analysis and subsequent interpretation of environmental gradients.
Benthic invertebrate fauna of an aseasonal tropical mountain stream on Bougainville Island, Papua New Guinea
Authors: Yule CM
Published: November 2005

The benthic invertebrate fauna of Konaiano Creek, a small aseasonal mountain rainforest stream on Bougainville Island, Papua New Guinea, was studied over a period of 22 months. Konaiano Creek supported a diverse, mostly undescribed, fauna dominated by two closely related species of Simuliidae (55% of the total specimens collected) and two species of Hydropsychidae. Over 182 taxa were recorded, more than half of which were Diptera. Species richness in Konaiano Creek was quite high in comparison with that of similar streams in both tropical and temperate regions. There were 31 species of Trichoptera, but there were no Plecoptera, Mollusca, Psephenidae, or Megaloptera. Although many groups of marine origin such as Gastropoda, Atyidae, Palaemonidae and fish inhabited nearby coastal rivers, these animals were apparently unable to colonize high mountain streams because of the torrential, barren nature of the mid-mountain streams that sharply divide the headwater streams from the lowland rivers on Bougainville Island.
Post-larval recruitment of blacklip abalone (Haliotis rubra) on artificial collectors in southern Tasmania
Authors: Nash WJ , Sanderson JC , Bridley J , Dickson S , Hislop B
Published: November 2005

Recruitment rates of blacklip abalone (Haliotis rubra) post-larvae were measured at fortnightly intervals for a year in southern Tasmania on larval collectors made of transparent, corrugated plastic. The settlement plates were conditioned prior to use in a flow-through sea-water system in a two-stage process. A film of diatoms (mainly Nitzschia and Navicula species) was first established on the plates, which were then grazed by juvenile H. rubra. This allowed second-phase algae (principally Myrionema species) to become established. The plates were then periodically deployed at a depth of ~7 m. Larval settlement occurred mainly during the austral winter and early spring. A peak settlement rate of 1408 post-larvae per collector (2347 post-larvae m-2) occurred in mid August. Methods of measuring larval or immediate post-larval abundance are reviewed with regard to their use in the assessment and management of abalone fisheries.
Diatom diet of abalone post-larvae (Haliotis midae) and the effect of pre-grazing the diatom overstorey
Authors: Matthews I , Cook PA
Published: November 2005

Gut content analyses of abalone post-larvae (H. midae) that settled on diatom-covered surfaces were conducted to determine selectivity in feeding. Diatoms were counted by the Utermohl method and scanning electron microscopy was used for their identification. Results indicated that abalone post-larvae preferred prostrate diatoms such as Cocconeis sublittoralis Hendey, Amphora proteoides Hustedt and Achnanthes brevipes Agasdh but would consume the more loosely packed, overstorey species such as Delphineis karstenii (Boden) Fryxell, Diploneis placida (Schmidt) Hustedt and Nitzschia palea (Kiitzing) Wm. Smith if their preferred food was not available. Pre-grazing of settlement surfaces by juvenile abalone before the introduction of larvae removed most of the overstorey
diatoms but left the preferred species virtually intact.
Recruitment of juvenile abalone (Haliotis spp.) measured in artificial habitats.
Authors: Davis GE
Published: November 2005

In September 1989, 45 concrete block habitats were deployed at three sites 25 km apart along the southern shores of Santa Rosa and Santa Cruz Islands, California, at depths of 10-16 m. In October 1989, 7200 small (≈ 41 mm) hatchery-reared red abalone, Haliotis rufescens, were introduced into 36 of the habitats. Nine habitats remained empty as controls. The habitats were surveyed in situ periodically for two years. Sufficient numbers of native abalone, H. rufescens and H. corrugata, were detected (315) to identify spring recruitment events. Habitats with introduced abalone contained more than twice as many native abalone as did empty control habitats during the first year. Average densities of native abalone in the artificial habitats (0.011 m-2) approximated densities of young-of-the-year abalone discovered by previous destructive sampling in natural habitat. Approximately 32% of the introduced abalone survived one year and 24% survived two years. Three to eight artificial habitats were sufficient to detect 20% differences in mean abalone densities during peak spring recruitment events.
Recruitment variation in abalone: Its importance to fisheries management
Authors: McShane PE
Published: November 2005

Recruitment failure has been implicated in the decline of several abalone fisheries. Traditionally, fisheries scientists invoke theoretical stock-recruitment relationships to predict trends in abundance of an exploited stock under various harvest regimes. The empirical evidence in support of a positive relationship between spawning stock and recruits is not strong. A further problem in interpretation of such relationships is that both 'stock' and 'recruitment' have various definitions in fisheries and ecological literature. The definition of a stock for abalone is not clear. As emphasized in this review, which considers each stage in the life history of abalone, the abundance of spawners is one of many sources of variation in recruitment. The evidence for invertebrates, particularly those with high fecundity, is that recruitment varies independently of the abundance of spawners. This is also the case for abalone, where recruits have been measured as the density of immediate post-settlement individuals, juveniles, or as adults entering the exploitable stock.
A problem with stock-recruitment hypotheses is that they have intuitive appeal. It is considered 'dangerous' to manage fisheries under the assumption that a reduction in the number of spawners by fishing will not affect recruitment. Such danger to abalone stocks has been more recently assessed by egg-per-recruit analyses, whereby various harvest strategies are examined relative to reference points for egg production. These studies are reviewed and assessed relative to the often conflicting aims of managers and scientists. This review of studies of recruitment variation in abalone emphasizes the need for a more rigorous, autecological approach to stock assessment in which field experiments are conducted over realistic spatial and temporal scales, permitting robust testing of hypotheses.
Good and bad fishing areas for Haliotis laevigata: A comparison of population parameters
Authors: Wells FE , Mulvay P
Published: November 2005

On the southern coast of Western Australia, proportionately more reproductive specimens of greenlip abalone, H. laevigata, were of legal size in 'good' fishing areas than in 'bad' fishing areas. Sex ratios were usually 1:1. Maturation of the gonads began at a size of 70-90 mm shell length (SL) and by 100-110 mm SL all animals were reproductively mature. Size-specific fecundities were not statistically different among the four good fishing areas examined, nor were they between the two bad fishing areas, but size-specific fecundity was greater in good than in bad fishing areas. Spawning begins as soon as the animals are mature; there is no gap between apparent histological maturity and actual spawning. Gonads are quiescent in the first part of the calendar year. Development is rapid in August and September, when animals begin to reach ripe condition. A maximum proportion of ripe animals occurs in October and November, followed by spawning in December.
There was no difference between growth rates of males and females in either the good or the bad fishing areas. The von Bertalanffy growth equation disclosed no difference in growth between good and bad fishing areas, but close inspection of the data suggested that slower growth did occur in the bad fishing areas. The abalone reach reproductive maturity at an age of 2.5 to 3 years and the legal size of 140 mm SL at 5 to 6 years.
Reproduction on two species of abalone (Haliotis iris and H. australis) in southern New Zealand
Authors: Wilson NHF , Schiel DR
Published: November 2005

Gonad development, spawning periodicity, fecundity and recruitment of two species of abalone, Haliotis iris and H. australis, were examined at two sites. Female H. iris spawned in April and September 1986 and March 1987, and decreases in male gonad indices coincided with these events. Oocyte size frequencies showed that the summer-autumn (April 1986, March 1987) spawnings were more pronounced than that in September 1986. Gonad indices of H. australis were low in December 1985 and March 1986, but oocyte size frequencies in September 1986 and March 1987 indicated that other spawnings occurred. Gonad development within and between sites was variable, especially for H. australis. H. iris had a female : male ratio of 1 : 1 at one site and 1.7 : 1 at the other; H. australis was 1 : 1 at both sites. In H. iris, the smallest females with primary and mature oocytes were 56 mm and 69 mm respectively, and the smallest male with sperm was 80 mm. H. australis females had primary and mature oocytes at 61 mm, and the smallest mature male was 65 mm. Fecundity varied between species. At 80-90 mm, H. iris had 13 500 eggs and H. australis had 2.7 million eggs, but at 140 mm H. iris had 7 million eggs. A few recruits of both species were found in May-April 1986, probably the result of the previous September spawnings.
Perkinsus, a protistan parasite of abalone in Australia: A review
Authors: Goggin CL , Lester RJG
Published: November 2005

Perkinsus parasites are widespread in molluscs around the world. In 1985 and 1986, a die-back of greenlip abalone, Haliotis laevigata, occurred along part of the South Australian coast. Perkinsus olseni was abundant in H. laevigata from the die-back area and widespread around the Yorke Peninsula in other hosts. After the epizootic had passed, two attempts were made to repopulate the area by transplanting adult H. laevigata; the second attempt, in 1989, appears to have been successful. Laboratory experiments showed that abalone infected with P. olseni had a higher mortality rate than did uninfected abalone and that stress such as high temperature predisposed the abalone to disease. During winter, abalone appear able to contain and possibly eliminate the infection.
Molecular studies have indicated that there is a single species of Perkinsus in Australia that is widespread in abalone and bivalves from the Great Barrier Reef and South Australia but is not found in molluscs in Tasmania. This parasite, P. olseni, is similar to P. atlanticus from Portugal but different from P. marinus in North America. P. olseni was shown to be highly infectious to a range of molluscs in the laboratory.
P. marinus can be cultured in vitro; this will facilitate investigation into the susceptibility of the parasite to therapeutic agents, the mechanisms of host defence, and the affinities of Perkinsus parasites isolated from Australia and elsewhere.
Site selection by a small drilling predator: Why does the gastropod Haustrum baileyanum drill over muscle tissue of the abalone Haliotis rubra?
Authors: Thomas M , Day RW
Published: November 2005

The muricid gastropod Haustrum baileyanum bores holes through the shell of the abalone Haliotis rubra to feed on the underlying tissue. Analysis of the borehole positions on shells of H. rubra showed that they were significantly concentrated in the area where the abalone muscle is attached. This is in sharp contrast to other drilling predators of molluscs. The whelks did not change their choice of drilling site in response to experimental removal of the shell surface, or to changes in shell thickness. They may use shell ridges and possibly the morphology of the abalone shell to determine where to drill. The behaviour of the prey appears unlikely to affect the drilling position, and shell repair by the abalone is too slow to act as an effective defence in any area. The area over the muscle is the thickest part of the shell covering abalone tissue, and requires a much longer time to penetrate, as drilling is slow. The cost of drilling through the thicker part of the shell is presumably outweighed by the benefits gained from feeding on the muscle tissue. The muscle tissue has a higher energy content than the visceral tissue found elsewhere, especially when measured per unit volume.
Estimating the abundance of abalone: the importance of patch size
Authors: McShane PE
Published: November 2005

A method to assess the patch frequency and so derive estimates of relative abundance and biomass for populations of Haliotis iris is described. The eight populations of H. iris surveyed from southern New Zealand comprised mostly small patches (≤4 individuals). Larger patches were comparatively infrequent but their frequency varied among populations. Application of patch-frequency data to estimate relative abundance was validated with direct counts and a comparison with the collection rates from timed searches. Relative abundance, relative biomass and density were estimated from patch-frequency data. These measurements were more precise and less time consuming than direct estimates of density. The relatively short time per survey allowed replication, giving surveys the power to detect the changes in the frequency of patches expected to result from commercial fishing. A survey method to examine juvenile abundance is also described: abundance was weakly correlated with the frequency of large patches. The relative abundance of juveniles varied among H. iris populations possibly because of differences in wave exposure between habitats.
Studies on southern Australian abalone (Genus Haliotis), 16. Recruitment, habitat and stock relations
Authors: Shepherd SA , Partington D
Published: November 2005

The dynamics of a population of the greenlip abalone, Haliotis laevigata, was studied from 1978 to 1990 in Waterloo Bay, South Australia. During this period the fishery was closed from 1982 to 1986 and the size limit was increased in 1986. The spatial distribution of recruitment (measured as the abundance of the 2+ age class) was correlated during every year of study with a complex gradient comprising water movement, habitat complexity and predator density, and for six years of the study with depth. Recruitment in the six years from the closure was 2.7 times higher than that in the preceding seven years. stock assessment, fecundity, total mortality, size at sexual maturity, sex ratio.
The intensity of aggregation of the adult (≥4 years) fraction of the population varied with density and habitat complexity. Under intense fishing, aggregations were fewer and smaller. This paper weights stock abundance according to a model relating intensity of aggregation with fertilization success and presents a stock-recruitment relation for the Waterloo Bay population. The curve is a classical Ricker type showing compensation at high stock sizes. This curve indicates that below adult densities of about 0.15 to 0.2 m-2 the population is increasingly vulnerable to recruitment failure and ultimately to collapse.
Behaviour studies on the mobility of two species of abalone (Haliotis tuberculata and H. discus hannai) on sand: Implications for reseeding programmes
Authors: Werner I , Flothmann S , Burnell G
Published: November 2005

The moving behaviour of two species of abalone (H. tuberculata and H. discus hannai) on sand was studied in laboratory experiments with two size classes. Test animals of all experimental groups left solid substrata and moved across sand areas. The smaller size class (11-22 mm) was significantly less mobile than the larger size class (29-40 mm) in both species, and H. discus hannai showed higher mobility than did H. tuberculata. Lack of food was a significant incentive to move for both species and both size classes. For H. discus hannai, the stress of handling and exposure to the new environment caused increased movement that decreased as the animals acclimated. The significance of these findings for fisheries management and reseeding programmes is discussed, in particular as a possible explanation for the frequently reported 'unaccounted for' lost seed abalone.
Evaluation of abalone stock enhancement through the release of hatchery-reared seeds
Authors: Kojima H
Published: November 2005

The Abu Fishery Cooperative has planted hatchery-reared seed of the abalone Haliotis discus discus since 1981. The number of 15-40-mm seeds planted annually varied from 34000 to 180000 between 1981 and 1992. Catches were sampled on seven to 10 days during each fishing season (29-56 days between July and September) from 1983 to 1992. The numbers of both seeded and wild abalone were recorded per 8-kg shipping basket on each sampling day. The numbers of seeded abalone in the catch were estimated by a two-stage sampling method. Variances were estimated from the data, which were stratified into two periods: the first when divers dived at depths of less than 5 m, and the second during the subsequent period of deeper diving. The values of these variances were substantially lower than the values of variances estimated from unstratified data. Some of the planted abalone reached 90 mm in length 21 months after seeding, and they could not generally be found in the wild stock after the age of 6 years. Recapture rates were estimated to range from 12% to 51% in the 1980-85 year classes that had been fished for their entire lives.
Spatial variability in the nekton of a canal estate in southern New South Wales, Australia, and its implications for estuarine management
Authors: Lincoln Smith MP , Hawes PMH , Duque-Portugal FJ
Published: November 2005

The nekton of a canal development in NSW, Australia, is described. Two sites each were sampled from the main canal and in end canals. The main canal had more species of fish than did the end canals, but the number of individuals was similar between locations. Abundance of particular species showed three patterns: species that were more abundant in either location, species that varied between locations and sites, and species that did not differ significantly in abundance. There was little evidence that the nekton from the end canals, which are presumably less well flushed, was depauperate compared with the main canal. Surveys of nekton in canal estates should incorporate spatial variability at two or more scales so that the effects of these human developments can be assessed properly.