bluuebunny/crossref_metadata_2025 huggingface dataset:
Commensalism Between an Epizoic Limpet, Patelloida nigrosulcata, and Its Gastropod Hosts, Haliotis roei and Patella laticostata, on Intertidal Platforms off Perth, Western Australia
Authors: Scheibling RE , Evans T , Mulvay P , Lebel T , Williamson D , Holland S
Published: November 2005

On intertidal limestone platforms off Perth and neighbouring islands, the limpet Patelloida nigrosulcata occurs only on the shells of living abalone (Haliotis roei) and other limpets (Patella laticostata). The incidence of commensalism varies among sites and between habitats within sites but is consistently high (> 80%) among dense abalone populations along the seaward margin of platforms. There is usually only 1 limpet per shell, although 2 or 3 limpets occasionally co-occur. A strong positive relationship in size (shell length) between Patelloida nigrosulcata and H. roei indicates that limpets settle on juvenile abalone and grow at a rate proportional to the growth rate of their host. A similar size relationship exists between Patelloida nigrosulcata and Patella laticostata. Patelloida nigrosulcata forages diurnally from a home scar and markedly limits the growth of erect macroalgae on the host shell. Escape from intense interspecific competition with other molluscan grazers on the platforms may have been a strong selective force in the evolution of this commensal relationship.
Fauna of the Annan River System, far North Queensland, with reference to the Impact of Tin Mining. I. Fishes
Authors: Hortle KG , Person RG
Published: November 2005

Fish were sampled at a range of sites in the Annan River system in tropical northern Queensland, using a variety of methods. In all, 25 species were recorded, including 14 principal freshwater forms. Species richness increased in a downstream direction and was directly related to stream size, the best measures of which were catchment area and stream length. When adjusted for stream size, the fish fauna of the Annan River system is relatively rich, compared with temperate Australian systems and streams on other continents. Analyses of gut contents of the species found in fresh water showed that six species were carnivorous, four were omnivorous, three were algivorous or detritivorous, and one was piscivorous. Mining impacts were evident at three sites and were associated with a reduced number of species; those eliminated were apparently less tolerant of sediment.
Interspecific differences in the distribution of adult and juvenile ponyfish (Leiognathidae) in the Gulf of Carpentaria, Australia
Authors: Staunton-Smith J. , Blaber S. J. M. , Greenwood J. G.
Published: November 2005

The distribution of leiognathids was investigated at 261 sites spread
throughout the Gulf of Carpentaria. Eight species,
Gazza minuta, Leiognathus decorus,
L. equulus, L. fasciatus,
L. leuciscus, L. smithursti,
L. splendens and Secutor ruconius,
were usually restricted to coastal areas, whereas four species,
L. bindus, L. moretoniensis,
Leiognathus sp. and S. insidiator,
were not. Two other species, L. aureus and
L. elongatus, were caught at only one site each. The
relationships between size of fish and depth in Albatross Bay were
investigated by examining the mean weight and minimum and maximum lengths of
different species in 356 trawls. Six of the coastal species showed the common
pattern of linear increase in size with depth. This pattern is consistent with
the existence of estuarine and/or inshore nursery areas, and supports
previous observations of these species. In contrast, three of the widespread
species exhibited approximately quadratic relationships between size and
depth. This unusual pattern resulted from small fish living in both the
shallow inshore areas and deeper offshore areas, and it may reduce competition
among the juveniles of the large number of very abundant, coexisting species
of leiognathid.
Contamination-free sample collection and handling protocols for trace elements in natural fresh waters
Authors: Ahlers WW , Reid MR , Kim JP , Hunter KA
Published: November 2005

Techniques that minimize contamination artefacts in the collection, handling and analysis of natural freshwater samples for dissolved trace metals are described. Methods were evolved during a 5-year study of a pristine high-altitude catchment in New Zealand, during which the dominating influence of contamination artefacts arising during the sampling operation was realized. Even with clean-room analysis facilities, order-of-magnitude contamination at the microgram per litre level was easily introduced at this earlier stage. The study calls into question much of the published literature that reports freshwater concentrations of trace elements in the microgram per litre range and below, particularly for Zn, Cd, Hg and Pb in systems whose pollutant sources are not definitively identified. We suggest that a base criterion for the reliability of trace-element measurements in natural fresh waters should be a similarity of spatial and temporal trends with those of conventionally measured properties such as major ions, alkalinity and electrical conductivity.
Structure of fish assemblages in waters of the Southern Acid Peat Flats, South-western Australia
Authors: Pusey BJ , Edward DHD
Published: November 2005

The structure of freshwater fish assemblages in waters of the southern acid peat flats of south-western Australia was monitored over a 3-year period. Nine locations were sampled during the course of the study; they differed in the permanence of the water supply and the degree of isolation from permanent water. The climate of the region is a Mediterranean one of high predictability (i.e. pronounced seasonality and low interannual variation). Consequently, temporary aquatic habitats were also temporally predictable in incidence and duration and were colonized by a comparatively rich fish fauna. Differences in habitat permanence and isolation were reflected in the structure of the fish assemblages, with temporary, highly isolated habitats being dominated by aestivating species. Temporary habitats not isolated from permanent water had the highest species richness and also contained one aestivating species. Permanent water habitats had the lowest species richness and diversity and were dominated by a single species (Edeba vittata). The assemblages changed little during the period of study with respect to species persistence and structure.
Heat uptake and resistance to mixing in small humic forest lakes in Southern Finland
Authors: Bowling LC , Salonen K
Published: November 2005

The annual heat budgets and maximum thermal stabilities achieved by small Finnish forest lakes are considerable for lakes of their size. Heat uptake is rapid during the brief period of vernal circulation, with the latent heat of fusion of ice contributing substantially to this. Heating then slows, with maximum heat contents and thermal stabilities occurring around early August. Absorption of solar radiation by the dystrophic waters, effective shelter from wind-induced turbulence, and considerable relative depths all combine to prevent mixing of heat much below the surface 2 m of most study lakes. Birgean wind-work values therefore remain low, and cold hypolimnetic waters occupy much of the lake volume. The lakes also respond quickly to meteorological change, which causes considerable year-to-year variation, and some short-term fluctuation, in their heat budgets and maximum stabilities. The lakes' small size and shallow thermal stratification may contribute to this.
Influence of soil clay content on dissolved organic matter in stream waters
Authors: Nelson PN , Cotsaris E , Oades JM , Bursill DB
Published: November 2005

Dissolved organic carbon (DOC) is of major importance for freshwater ecology and water treatment, particularly in Australia. Work comparing two small catchments, one yielding water with high DOC concentrations (Lawless) and the other yielding water with low DOC concentrations (Retreat Valley), is described. Differences between stream DOC concentrations in the two catchments were related to differences between the properties of the catchment soils. The Retreat Valley soils had higher C contents than the Lawless soils, but the C was less soluble, resulting in lower DOC concentrations in soil core leachates. The lower solubility of C in the Retreat Valley soils was the result of a higher clay content and hence a higher surface area for adsorption reactions. The Retreat Valley soils had a higher adsorption capacity for organic matter than did the Lawless soils. The clay contents of soils was found to be an important factor influencing stream DOC concentrations throughout the Mt Lofty Ranges, and the prediction of DOC concentrations in streams on a broad scale is discussed.
Pre-and post-flood feeding ecology of four species of juvenile fish from the Logan-Albert Estuarine System, Moreton Bay, Queensland
Authors: Sumpton W , Greenwood J
Published: November 2005

The feeding ecology of the four dominant species of juvenile fish found in the Logan-Albert estuarine system are described in terms of the stomach contents of 675 fish examined over a 7-month period. Ontogenetic dietary changes and spatial, temporal and interspecific differences in diet were determined. Johniops vogleri and Polynemus multiradiatus were predominantly planktonic feeders. At an early stage of development, these fish fed mainly on copepods, which were progressively replaced by larger prey such as mysids and Acetes as the fish grew. Arius graeffei and Aseraggodes macleayanus were mainly benthic feeders. Spatial and temporal differences in diet were also evident for each species. These differences probably reflected changes in prey availability resulting from flood-induced changes to the salinity gradient. The potential for competition between Johniops vogleri and Polynemus multiradiatus was reduced by temporal partitioning of food resources as the fish grew.
Large-scale patterns in habitat structure on subtidal rocky reefs in New South Wales
Authors: Andrew N. L. , O'Neill A. L.
Published: November 2005

Aerial photography was used to estimate the
representation of shallow subtidal habitats in New South Wales. Sixty sites,
each between 4 and 5 hectares, were mapped with Geographical Information
Systems software using ortho-rectified images digitized from 1:8000-scale
photographs and ‘ground truthed’ in the field by divers. Barrens
habitat covered an estimated 50% (s.e. = 3.9) of nearshore reefs
between Port Stephens and Disaster Bay. Coverage of barrens habitat was
greatest in Disaster Bay (68%, s.e. = 6.7) and least south of
Disaster Bay (1%, s.e. = 0.3). There were clear differences
among localities in the area of reef within the mapped sites; those at Cape
Howe, Nadgee, and Turingal were significantly smaller in area than all others.
There was no clear latitudinal trend in these differences but there was
evidence of sand inundation at a site at Nadgee, where the reef was small.
Differences in the densities and size-structure of the sea urchin
Centrostephanus rodgersiiat 27 of the mapped sites
provide a basis for testing relationships between the demography of this
species and the persistence of the barrens habitat. The extensive coverage of
the barrens habitat in New South Wales is likely to limit the productivity of
the abalone industry. The development of a sea urchin fishery may have large
impacts on habitat representation on nearshore reefs.
Aspect of the reproductive biology of the Gummy Shark, Mustelus antarcticus Gunther, from waters off the South coast of Western Australia
Authors: Lenanton RCJ , Heald DI , Platell M , Cliff M , Shaw J
Published: November 2005

The gummy shark (Mustelus antarcticus) is a major target species in two substantial shark fisheries that operate in temperate Australian waters. Data on the reproductive biology of M. antarcticus in the waters off south-western Australia were obtained from samples collected by commercial vessels operating from Albany to Esperance, Western Australia. The samples contained a ratio of four females to one male. M. antarcticus is a viviparous, aplacental species. Males mature at a smaller size than females. Since the overwhelming majority of sharks sampled were mature, it was not possible to estimate precisely the mean size at which sexual maturity was attained. Examination of seasonal changes in the development of ova and testes, in uterine contents, and in embryo growth established that the period of parturition, mating and ovulation occurred over the 3 months between early November and early February. The gestation period was 11-12 months. Full-term embryos ranged in size from 30 to 36 cm total length and occurred in a sex ratio of one male to one female. The ovarian and gestational cycles proceed concurrently, with reproduction occurring annually. Only one of the 224 females analysed for uterine content was considered to be in a true post-partum condition. The number of embryos (N) per mother increased with the length of the mother (L) according to the regression N = exp(-4.13398 + 0.049171L). The reproductive biology of females collected off Albany and Esperance differed in some respects from that of females collected off south-eastern Australia.
Dispersal among populations of Caridina sp. (Decapoda : Atyidae) in coastal lowland streams, south-eastern Queensland, Australia
Authors: Woolschot Leisl , Hughes Jane M. , Bunn Stuart E.
Published: November 2005

Caridina sp. is an atyid shrimp occupying coastal
streams in south-eastern Queensland and northern New South Wales. Shrimps from
two geographic regions in south-eastern Queensland were examined. An analysis
of 7 allozyme loci showed very high levels of genetic differentiation among
catchments (F ST = 0.65) with much lower levels
within catchments. This indicates extremely limited dispersal among catchments
with greater levels within catchments. The levels of genetic differentiation
were even greater than previously reported for two other atyid shrimp species
occurring in upland rainforest streams. Populations from the Noosa River were
more similar to those from the Glasshouse Mountains than to those from the
geographically closer Tin Can Bay streams. This pattern was remarkably similar
to that of a fish species occurring in the same streams and may reflect a
recent confluence of streams from the Glasshouse Mountains and the Noosa River
regions.
Population estimates and size structure of Plectropomus leopardus (Pisces : Serranidae) in relation to no-fishing zones: mark-release-resighting and underwater visual census
Authors: Zeller D. C. , Russ G. R.
Published: November 2005

A mark–release–resighting (MRR)
technique was used to estimate population size of the coral trout,
Plectropomus leopardus, on coral reefs fringing Lizard
Island, Great Barrier Reef, Australia. Fish were captured by hook-and-line
fishing, and marked with individual freeze-brand numbers in August 1995. An
underwater visual census (UVC) technique was used during September and October
1995 both for resighting of marked fish and to make an independent estimate of
fish density and thus population size. The study area was 750 966
m2 . The UVC sampled 154 000 m2
(20.5%) of this area. Six different methods of analysis of MRR gave
similar population size estimates (e.g. Petersen 12 873; 95% CI
9989–15 754) extrapolated to the 4.5 million-m2
reef area from datum to 20-m depth around Lizard Island. UVC gave a population
size estimate (24 182; 95% CI 21 860–26 504) twice that of MRR.
The lower estimate derived from MRR may be the result of tag-induced
mortality, or of the relative difficulty in discriminating between marked and
unmarked trout by UVC. This is only the second estimate of population size of
coral trout on an area of the Great Barrier Reef.
Spatial variation in size and age structures and reproductive characteristics of the King George whiting (Percoidei : Sillaginidae) in South Australian waters
Authors: Fowler A. J. , McLeay L. , Short D. A.
Published: November 2005

Adult King George whiting were sampled at 12 localities representing a range
of habitat types across South Australia. Sampling was undertaken between March
and May for a minimum of 2 years between 1995 and 1998. Fish were aged by
otolith interpretation, and reproductive maturity was determined by gonad
analysis using macroscopic and histological techniques. In total, 6961 fish
comprising 3678 females and 3283 males were considered from four localities in
each of three geographic regions. In both Gulf St Vincent and Spencer Gulf,
age structures became more complex from north to south, associated with a
shift in size towards larger fish. In the simplest age structures,
>90% of fish were from the 3-year age class, whereas the age range
of the most complex was 3–17 years, with the 3–5 age classes most
numerous. Males were more abundant in smaller size classes and females in the
larger. Although some fish from each locality showed some gonad development,
only at three localities did spawning occur. At these places, populations had
the broadest age and size distributions and were in deep water that
experienced medium to high wave energy. Since spawning grounds and nursery
areas are up to several hundred kilometres apart, the processes of larval
advection and adult movement are implicated as obligate processes of the life
history.
Numerical simulations using a population model of three cladoceran species, Daphnia magna, D. galeata and Bosmina longirostris, in a single-species and a competition environment
Authors: Asaeda Takashi , Acharya Kumud
Published: November 2005

Models were simulated for single species and
two species together, to study population levels, food assimilation and usage
for reproduction, average brood sizes, and effect of two levels of food on the
time of first reproduction. In the simulation of a single-species population,
both species had higher numbers in abundant environmental food conditions,
whereas the smaller species had relatively better numbers than the larger
species when food was less abundant. In the simulated two-species competition,
the larger species dominated when food was abundant, whereas the smaller
B. longirostris outnumbered the larger
Daphnia species when food availability was low. The
biomass conversion based on the length–weight relationship gave
different results: even under low-food conditions the larger species, although
few in number, had a clear dominance over their
smallerBosmina counterparts in terms of biomass. At both
food levels, the proportion of young adults (adolescents) and adults to
juveniles was considerably higher in B. longirostris
than in the Daphnia species.
Extra keyword: assimilation
Woody plant restoration and natural regeneration in wet meadow at Coomonderry Swamp on the south coast of New South Wales
Authors: de Jong N. H.
Published: November 2005

This study investigated planting techniques and natural regeneration of
indigenous woody species within degraded wet meadow wetland at Coomonderry
Swamp. Planting tubestock directly into existing vegetation was practical and
cost-effective. Clearing of plots allowed infiltration of weeds, early growth
of tubestock was inhibited, acid sulfate soils were exposed, and open
inundated plots were choked by algae. After four years,
Melaleuca ericifolia and
Melaleuca linariifolia showed good survivorship at upper
and lower elevations. Eucalyptus robusta and
Casuarina glauca were more successful at upper
elevations, and Leptospermum juniperinum did not succeed
at either elevation. These results corresponded to patterns of regeneration
and to distributions within undisturbed stands. Despite the evidence of
natural regeneration, direct seeding was not successful at the experimental
site. Given that poor dispersal was indicated at Coomonderry Swamp, it is
unlikely that isolated wetlands in the region could rely solely on seed
dispersal for woody revegetation. Even where regeneration can occur naturally,
some planting or culling might be required if the desired outcome is a species
mix comparable to that observed on undisturbed margins.
Short Communication: Simple morphometric characters, confirmed by gel electrophoresis, separate small juvenile banana prawns (Penaeus indicus and P. merguiensis)
Authors: Pendrey R. C. , Loneragan N. R. , Kenyon R. A. , Vance D. J.
Published: November 2005

The juveniles of red-legged banana prawns
Penaeus indicus and white banana prawns
P. merguiensis are difficult to distinguish. Gel
electrophoresis, with the enzyme malate dehydrogenase, clearly separated into
species both large and small prawns. Four morphological characters were
measured from juvenile prawns (identified using electrophoresis): three of
these provided reliable separation into species. The mean ratio of the
distance from the anterior-most dorsal rostral tooth (first tooth) to the tip
of the rostrum (L 1 ): to the distance between this
tooth and the second tooth (L 1,2 ) was higher for
P. indicus (3.16) than
P. merguiensis (1.56). All juvenile
P. indicus had the first tooth posterior to the
antennular peduncle, while it was anterior for all
P. merguiensis. More than 90% of
P. indicus had six rostral teeth behind the eye, while
over 90% of P. merguiensis had five teeth behind
the eye. Damage to the rostrum prevented measurements of the position of the
first tooth in 20 to 30% of juvenile prawns. Combining the measurements
of the ratio of L 1 : L 1,2 and
the count of the number of rostral teeth behind the eye meant that all prawns
could be unambiguously identified.
Influence of abiotic and biotic factors on two co-occurring species of Bolboschoenus
Authors: Siebentritt Mark A. , Ganf George G.
Published: November 2005

Distribution of the emergent macrophytes
Bolboschoenus medianus and
Bolboschoenus caldwellii is dominated by the latter at
regions higher on the elevation gradient, whereas the former is dominant
further down the gradient. Monocultures and mixtures of plants were grown
across a water-depth gradient in experimental ponds to determine whether
distribution is due to abiotic factors, biotic factors, or a combination of
both. Monocultures of each species tolerated exposure, showing little
variation in relative growth rate (RGR), net assimilation rate (NAR) or leaf
area ratio (LAR). Survival when initially flooded was dependent on shoot
height. Plants surviving inundation responded by increasing height through
reallocation of biomass. The RGR of B. medianus was
maintained across the water-depth gradient by increasing NAR as LAR declined.
The RGR of B. caldwellii beyond a depth of −20 cm
declined because reductions in LAR were not paralleled by increases in NAR.
Mixtures of species growing at 20 cm and 0 cm indicated that biotic
interactions occurred and that B. caldwellii was the
dominant species. Neither species dominated at −60 cm, presumably
because this was beyond the depth tolerated by both species. The study
suggests that the zonation of B. medianus and
B. caldwellii is attributable to a combination of both
abiotic and biotic factors.
Temperature effects on embryo and early larval development of the spiny lobster Jasus edwardsii, and description of a method to predict larval hatch times
Authors: Tong Lennard J. , Moss Graeme A. , Pickering Timothy D. , Paewai Megan P.
Published: November 2005

Ovigerous spiny lobsters
(Jasus edwardsii) with known egg extrusion dates were
held at four temperatures and embryo development was monitored at weekly
intervals. Times to hatch were approximately 65 days, 95 days, 155 days and
163 days at 18˚C, 15˚C, 12˚C and ambient temperatures
(9–14˚C) respectively. For the embryos, the appearance of the
median eye, the eyes and the chromatophores, and an eye index, were used to
calculate the biological zero, i.e. the theoretical temperature at which
development ceases, which, for J. edwardsii, was
7.53˚C. A formula based on the eye index was then derived to predict time
to hatch at a range of temperatures using the cumulative difference between
the rearing temperature and the biological zero. Data were also collected on
the time between females moulting and mating, the total number of larvae
successfully hatched for a range of female sizes and Stage I phyllosoma larval
size in relation to the embryo-rearing temperature.
Sustainability indicators for fisheries in integrated coastal area management
Authors: Perrings Charles
Published: November 2005

The paper reviews the limitations of
decentralized economic indicators (market prices) of the effect of
land–ocean interactions on marine capture fisheries, considers the
potential for improvement of those indicators, and identifies alternative
indicators that can inform remedial policy where there is market failure. The
primary indicators of the impact of land–ocean interactions on marine
capture fisheries are decentralized prices net of the effect of taxes and
subsidies; these are the indicators that guide private use of watersheds, and
estuarine and coastal systems.
Indicators for assessing the sustainability of Australia's marine ecosystems
Authors: Ward Trevor J.
Published: November 2005

Principles of integrated ecosystem-based
management have been used to derive 61 potential environmental indicators for
reporting on Australia’s marine and estuarine ecosystems. They are
focused on tracking the condition of marine ecosystems in the face of a
variety of uses and pressures, and are consistent with approaches used for
assessment of public- and private-sector environmental activities, and with
the international standard. The in icators cover issues in protected species,
common habitats, renewable and non-renewable resources, water and sediment
quality, and integrated management. Gaps in knowledge and technical capacity
include: knowledge of the nature of the ecosystems is incomplete (ineffective
indicators may be selected); scientific understanding of environmental issues
is limited (the wrong cause may be identified); the resolving capacity of a
monitoring programme cannot be determined (monitoring may falsely infer that
no changes have occurred, or provide an answer to the wrong question);
procedures for synthesis and aggregation of data across spatial, temporal and
taxonomic scales, or for estimating uncertainty in national summaries are
lacking; case-study trials, reference sites, and suitable interpretative
models are needed; and an established procedure for revising and updating the
indicators as new knowledge accrues, or if new issues arise, is lacking.
Technical background to fish stock indicators for state-of-environment reporting in New Zealand
Authors: Gilbert David J. , Annala John H. , Johnston Kirsty
Published: November 2005

Pressure–state–response
environmental indicators are proposed for New Zealand fish stocks. This
workwas a technical background to the development of a core set of indicators
sought by the Ministry for the Environment. It has led, through an extensive
programme of consultation, to a set of confirmed indicators. The initial
proposals and their basis are described together with their relationship to
the confirmed indicators. The proposed indicators could readily be calculated
as part of the stock assessments conducted annually by the Ministry of
Fisheries and this is recommended. For many stocks, especially minor stocks,
only proxies for the preferred indicators would be possible. The proxy
indicators would not be useful in all cases, and target or threshold values
for them could generally not be calculated. Shortcomings and difficulties in
the proposed indicators are described. A state indicator that separates
changes induced by fishing from those of a natural origin is described, but it
could be obtained for only a few stocks.
Integration of sustainability indicators: the contribution of integrated economic and environmental accounting
Authors: Willmann Rolf
Published: November 2005

There is a need to integrate indicators
relating to complex human–nature systems. This paper discussesthe scope
and limitations of achieving such integration through the interim version of
the system of integrated environmental and economic accounting (SEEA)
published by the United Nations in 1993. It also briefly considers alternative
or complementary approaches such as the National Accounting Matrix including
Environmental Accounts (NAMEA) developed in the Netherlands. Issues that arise
when applying SEEA to the marine fisheries sector are discussed, and examples
are given of indicators for the marine fisheries sector derived from the SEEA
and NAMEA.
Using indicators to measure sustainability: recent methodological and conceptual developments
Authors: Dahl Arthur Lyon
Published: November 2005

This paper briefly reviews some of the
progress made to address the issues of measuring sustainability since the Rio
‘Earth Summit’ in 1992. It provides the broader context within
which to integrate indicators of fisheries sustainability. Although the
immediate focus of fisheries indicators will be to achieve sustainability in
the management of each fishery, it will also be necessary to aggregate some
appropriate indicators geographically and temporally for global measures of
fisheries sustainability. Conversely, global indicators of pressures on
fisheries are needed as inputs to local sustainability calculations.
Age and growth estimates for the tiger shark, Galeocerdo cuvier, from the east coast of South Africa
Authors: Wintner S. P. , Dudley S. F. J.
Published: November 2005

Growth rings (GR) in sagitally sectioned vertebral centra of 69 female tiger
sharks (102–300 cm precaudal length; 6–412 kg) and 32 males
(123–301 cm; 16–396 kg) were counted. In vertebrae from three
sharks injected with oxytetracyline (OTC) and recaptured after 18, 389 and 791
days of liberty, respectively, OTC was visible and there was evidence of
annual GR deposition. Centrum analyses of the entire vertebral sample failed
to confirm this GR periodicity. Assuming annual GR deposition, the youngest
female and male aged were 1 year (102 cm) and 2 years (123 cm), and the oldest
were 11 years (293 cm) and 8 years (301 cm) respectively. von Bertalanffy
parameters for the combined sexes based on back-calculated values were
L• 301 cm, k 0.202
year−1 and
t0 −1.11 years. Ages
calculated for length at 50% maturity were 11 years (274 cm) and 8
years (250 cm) for females and males, respectively. Calculated growth in
length decreased from 44 cm (0–1 year) to 4 cm (12–13 years).
Gompertz parameters were w0 14 kg,
G 3.73 and g 0.172
year−1. Calculated growth in mass increased from
12 kg (0–1 year) to 38 kg (7–8 years), then decreased to 29 kg
(12–13 years). Back-calculated length and mass values were similar to
observed values and Lee’s phenomenon was not evident in either case.
Uncertainty in bio-economic reference points and indicators of marine fisheries
Authors: Seijo J. C. , Caddy J. F.
Published: November 2005

The design of intelligent management plans for
marine fisheries requires recognition of the uncertainty of marine systems
when assessing fishery performance through the use of bio-economic indicators.
The uncertainty causing variability in the estimated values of the
bio-economic indicators is incorporated through the use of Monte Carlo
analysis to estimate the probability of exceeding limit reference points. To
account for natural variability and other sources of uncertainty, estimates of
appropriate fishery bio-economic indicators are needed in order to re-evaluate
the fishery periodically and establish new reference points and corresponding
management strategies. This paper concentrates on this aspect of the
management process. It presents a classification of indicators in accordance
with the level, change and structure framework. Alternative approaches to deal
with risk and uncertainty in data-limited management contexts are discussed.
Development of economic and social indicators for the management of Mediterranean fisheries
Authors: Bonzon Alain
Published: November 2005

The paper reviews recent attempts to select
economic and social indicators for the management of fisheries under the aegis
of the General Fisheries Commission for the Mediterranean. It outlines some
general conditions for the selection and describes aspects of the reference
framework specific to the Mediterranean, in a context of poorly defined
management objectives. Some of the difficulties in adopting performance
indicators at a sub-regional level, particularly in relation to determining
the appropriate scale of fleet segmentation, are discussed. With a view to
establishing a database on economic and social indicators for Mediterranean
fisheries, the need to standardize statistical approaches is emphasized.
Economic performance indicators for fisheries
Authors: Hundloe Tor John
Published: November 2005

An outline of the concept of sustainable
development is followed by a definition of the term ‘economics’
and a brief review of attempts to use economic principles to construct an
integrated indicator to replace gross domestic product. Arange of proxy
indicators is described; these are based on what is possible in countries that
have minimal fisheries data and where fishers are making decisions on the
crudest economic information.
Sustainable recruitment: the bottom line
Authors: Bravington Mark V. , Stokes T. Kevin , O'Brien Carl M.
Published: November 2005

This paper develops a single-species
perspective on the limits of sustainable fishing. Given uncertain data and
assessments, the problem is to determine lower confidence limits for the
minimum fishing mortality rate Ft that, if maintained indefinitely, would
drive the stock to extinction. For non-depensatory stocks, Ft is determined by
the slope of the stock–recruitment curve at the origin. The paper
reviews three different approaches to making inferences about Ft :
recruit-per-biomass relationships (e.g. F high ),
parametric curves (e.g. Ricker), and nonparametric curves (e.g. LOWESS fits;
Cook 1998). Of these, nonparametic curves are potentially the best, but
existing implementations suffer from operational difficulties and do not
always give biologically sensible fits. These problems can be circumvented by
two new nonparametric methods, CONCR (Concave Recruitment) and DIMPOS
(Diminishing returns, Positive recruitment), which are described and applied
to several ICES stocks. Finally, the paper explores issues surrounding the use
of sustainable recruitment measures in assessment and management.
A review of methodology used to measure leaf litter decomposition in lotic environments: Time to turn over an old leaf?
Authors: Boulton AJ , Boon PI
Published: November 2005

Despite the recognition of the relationship between microbial conditioning and invertebrate feeding, there has been little communication between microbial ecologists and zoologists studying the processing of leaf litter in streams. An appraisal of suitable methods is timely, to encourage workers to critically examine their experimental approach: it is often forgotten that results are determined largely by the methods used. We review some recent studies, emphasizing the application of microbiological and biochemical methods, and discuss some important decisions that must be made in experimental design and implementation. It is recommended that newly fallen, naturally abscissed leaves, bound in leaf packs and tethered to natural substrata, be used in studies attempting to simulate natural leaf decomposition. Drying and leaching leaves under extreme conditions should be avoided. Mass loss should not simply be equated with decomposition; instead, losses of the main types of chemical constituents of plant litter should be quantified. If the aim is to study decomposition rather than merely leaf breakdown, the metabolism of dissolved matter and fine particulate material lost from the decaying leaf must be addressed as well. Appropriate techniques should be used to study microbial assemblages: lipid biomarkers or nucleic-acid methods for assemblage composition, microscopy or biochemical analysis for microbial biomass, [3H]-thymidine or [3H]-leucine methods to determine growth rates. Exponential decay curves and processing coefficients should be used cautiously, especially if sample sizes are small and equal throughout the study.
Ecology and production of Nebalia sp. (Crustacea : Leptostraca) in a shallow-water seagrass community.
Authors: Rainer SF , Unsworth P
Published: November 2005

Nebalia sp. is an abundant epifaunal crustacean in seagrass meadows at Seven Mile Beach, Western Australia, in water temperatures of 16-27�C. Its maximum length is 6.0-6.4 mm; females generally reach maturity when 4 mm long and males when 5 mm long. They breed throughout the year, and juveniles comprised 94% of animals sampled (n = 880). Males comprised only 11% of mature animals in field samples, compared with 40% in field chambers and 67% in the stomachs of nocturnal fish predators. Abundance during the year reflected changes in growth rate (0.050-0.088 mm day-1), mortality rate (0.020-0.069 day-1) and life span (49-102 days). The annual production of Nebalia sp. in seagrass meadows was estimated at 5.8 g ash-free dry weight (AFDW) m-2, with a corresponding P :B (production:biomass) ratio of 22.5. Predation is probably the main source of mortality at times of high density of Nebalia sp., and at least three significant fish predators on Nebalia sp. were found. Together with Nebalia sp., small crustaceans with high P:B ratios may have a significant role in secondary production in the seagrass beds at Seven Mile Beach.
Marine fungi of Queensland, Australia
Authors: Kohlmeyer J , Volkmann-Kohlmeyer B
Published: November 2005

Collections of filamentous higher marine fungi gathered along sandy beaches and the mangal of Queensland yielded 43 species, of which 28 are new records for Australia. Six additional species have been recorded earlier but did not occur in this survey. The annotated list contains 43 ascomycetes, one basidiomycete and five anamorphic ('imperfect') fungi. Among the hosts and substrates are Avicennia marina, Avicennia sp., Osbornia octodonta, Pandanus sp., Rhizophora stylosa and Rhizophora sp. Massarina Iacertensis Kohlm. & Volkm.-Kohlm. sp. nov. is a new species on wood of R. stylosa from Lizard Island.
Effect of temperature on egg development in the Australian stonefly genus, Austrocercella Illies (Plecoptera : Notonemouridae)
Authors: Brittain JE
Published: November 2005

Eggs of four species of the endemic Australian stonefly genus Austrocercella-A. alpina, A. hynesi, A. illiesi and A. tillyardi-were incubated in the laboratory at constant temperatures at 5�C intervals between 5 and 25�C. For all species, there was a significant relationship between water temperature (T, �C) and length of egg incubation (Y, days), expressed by the logarithmic equation Y = aT-b, where a and b are constants. However, a linear plot, Y = a - bT, was a better fit for A. illiesi. All species displayed high hatching success between 5 and 15�C. At 20�C, successful hatching took place in A. hynesi and A. tillyardi, but in A. alpina virtually no eggs hatched. In A. illiesi, about 50% of the eggs hatched at 20�C, but the incubation period was prolonged. Interspecific differences in egg development within the genus Austrocercella reflect life-cycle timing and the temperatures likely to be experienced by the egg stage. The few intraspecific differences were also related to temperature during the egg stage. Austrocercella shows egg developmental relationships similar to those found in many northern hemisphere stonefly species, including the Nemouridae.
Plasma sex steroid concentrations in male blue cod, Parapercis colias (Bloch & Schneider) (Pinguipedidae), sampled underwater during the spawning season
Authors: Pankhurst NW , Kime DE
Published: November 2005

Blood samples were collected underwater from male blue cod (Parapercis colias) captured by SCUBA divers during the spawning season. Acute reproductive condition (degree of spermiation) and size were determined, after which the fish were released. In all, 82 fish were sampled during 13 dives in daylight hours over a 10-week period. Fish that were not spermiated were most common before 1000 hours, whereas most of the spermiated fish were captured after 1500 hours. Spawning has yet to be observed, but available evidence suggests that it occurs in the late afternoon or early evening, although it is not known how frequently spawning acts occur. Plasma testosterone (T) concentrations were variable but did not show consistent association with date, time of sampling, moon phase or acute reproductive condition. Plasma T was higher in large males than in small males in all spermiation stages. There was no clear relationship between plasma T and T-glucuronide concentrations. Plasma 11-ketotestosterone (IIKT) concentrations were less variable than T concentrations but, like T, were higher in large fish than in small fish. Plasma 17a,20�P-dihydroxy-4-pregnen-3-one (17,20�P was not detectable at any time, but the presence of 17,20�P-glucuronide (17,20�PG) indicated that 17,20�P was being produced and glucuronated before it accumulated to detectable concentrations in the plasma. In spermiated fish, 17,20�PG was elevated.
Distribution, size and sex composition, reproductive biology and diet of sharks from Northern Australia
Authors: Stevens JD , McLoughlin KJ
Published: November 2005

The distribution, size composition, sex ratio, reproductive biology and diet of 17 species of shark from the families Triakidae, Hemigaleidae and Carcharhinidae from northern Australia were examined. In most of these species the sex ratio of the embryos is 1 : 1, whereas in the post-partum populations there were significantly more males than females. The results indicate four broad reproductive strategies among these sharks. In most species reproduction was distinctly seasonal with individual females giving birth each Austral summer (annual cycle) after a gestation period of 9-12 months. A second group had a very similar cycle except that individual females gave birth every second year (biennial cycle). A third group had an annual cycle but breeding was continuous throughout the year, these were mostly small bottom-associated sharks. One species had a seasonal cycle but gave birth twice each year (biannual cycle) after a 6-month gestation. The average size at birth varied from 27 to 75 cm and the average litter size varied from 2 to 34. The size at birth was about 40% of the size at maturity, which in turn was about 70% of the maximum size. Diets ranged from omnivorous to highly selective. Fish was an important component of the diet in all but one species. There was evidence of partitioning of food resources among sympatric, morphologically similar, sharks.
A transfer function modelling approach to understanding the turbidity of a lake
Authors: Welsh DR , Stewart DB
Published: November 2005

Transfer function modelling, which is a statistical technique used to relate a dependent or output variable to one or more independent or input variables when there may be time lags between inputs and output, is used in this study to examine the dynamic relationships between the turbidity of the surface water of Lake Eppalock with the inflows from its tributary streams and rainfall. The formulation of transfer function models is considered first, then single-input and finally double-input models are given. Single-input models are identified using the sample cross-correlation function. The problems caused by correlated input series are overcome by identifying the double-input models with a biased regression technique. Akaike's Information Criterion is used to choose between competing models. The results indicate that the turbidity of the lake is mostly explained by the inflow from the Coliban River and the rainfall in the vicinity of the dam. We conclude that the catchment of the Coliban River and the foreshore of the lake are the most important regions affecting the turbidity of its surface waters.
The El Nino-Southern Oscillation in south-eastern Australian waters
Authors: Hsieh WW , Hamon BV
Published: November 2005

Using four decades of hydrographic data collected off the coast near Sydney, New South Wales, and sea-level data at Sydney, we studied the interannual variability in south-eastern Australian shelf waters. The first two empirical orthogonal function (EOF) modes of the band-pass-filtered 50-m-depth hydrographic data (temperature, T; salinity, S; nitrate, N; inorganic phosphate, P; and oxygen, O) and the sea level (SL) and adjusted sea level (ASL) data accounted respectively for 51 and 27% of the total variance. Both modes were significantly correlated with the Southern Oscillation Index (SOI). The first mode, with T, S, O and ASL varying in opposition to N and P, represented the internal or baroclinic response, associated with vertical displacements of the isopycnals. The second mode, with large in-phase fluctuations in SL and ASL but small changes in the hydrographic variables, represented mainly the external or barotropic response during the El Niiio-Southern Oscillation (ENSO). Three-year composites centred around seven ENSO warm episodes revealed that T, S, O and ASL were generally low and N, P, SL and SO1 were high in the year before each ENSO warm episode, but the former group rose while the latter group dropped in the year of the warm episode. The changes in the hydrographic variables at 50 m depth were consistent with relatively shallow isopycnals in the year before the ENSO warm episode, followed by a deepening of the isopycnals during the warm episode. Estimates of this downward displacement of isopycnals, as determined from T, N, P and O, were in the range 7-10 m. The geostrophic wind arising from the pressure fluctuations during ENSO is proposed as a probable cause for the vertical displacement of the isopycnals. In the year before the warm episode, the low air pressure over Australia would produce a clockwise geostrophic wind around south-eastern Australia, generating offshore Ekman transport and coastal upwelling. During the warm episode, air pressure over Australia rises, the geostrophic wind reverses, and downward movement of the isopycnals would occur off south-eastern Australia.
Polyorganosiloxanes (Silicones) in the aquatic environment of the Sydney region
Authors: Batley GE , Hayes JW
Published: November 2005

Polyorganosiloxanes, or silicones, common ingredients in a range of modern domestic and industrial formulations, have been detected in waters, surface microlayer samples, sewage discharges and estuarine sediments collected from the coastal zone near Sydney, New South Wales. High concentrations in sewage sludge (>100�g Si g-1) are not reflected in waters receiving a sewage discharge. However, the high affinity of hydrophobic silicones for large-surface-area clayey sediments leads to wide variability within a single waterbody, indicative of localized inputs. Furthermore, the fine structure of organosilicon sediment-depth profiles affords an excellent chemical indicator of a 1950 horizon, the approximate date of introduction of these compounds to Australia.