bluuebunny/crossref_metadata_2025 huggingface dataset:
A magnetometer instrumentation technique using a miniature transducer
Authors: Fales C. L. , Breckenridge R. A. , Debnam W. J.
Published: February 2004

This paper describes a magnetometer with a miniature transducer which can be scanned automatically. The active area of the transducer is 0.64×0.76 mm and its drive circuit is constructed from wire plated with a magnetic coating. The magnetometer is capable of detecting static magnetic fields as low as 0.02 Oe and can measure magnetic fields as close as 0.08−0.10 mm from a relatively flat surface since the transducer is flat and rugged. The magnetometer is simple to operate and has a fast response. The instrument has been applied to the measurements of magnetic fields arising from remanent magnetization in experimental plated-wire memory planes and regions of magnetic activity in geological rock specimens.
Analog pulse divider
Authors: Johannsen Chr. R.
Published: February 2004

An analog pulse divider has been developed for use with one- and two-dimensional high-resolution, position-sensitive detectors. The dividing element is a four-quadrant multiplier. The accuracy is better than 1% over dynamic ranges of 1:10 for the energy signal and approximately 1:100 for the position signal, respectively. Division is carried out in approximately 12 μsec.
An oil displacement flowmeter for measuring low flows entering systems at subambient pressures
Authors: Umstead Merle E. , Woods Foster J.
Published: February 2004

A flowmeter has been developed for measuring gas flows in the range of a few milliliters per minute or less entering a reactor operated at subambient pressure. The flowmeter is based upon oil displacement, and is easily constructed from readily available laboratory materials.
Extraction of images from a very low temperature cryostat using fiber optics
Authors: Williams Gary A. , Packard Richard E.
Published: February 2004

A cryostat is described in which optical images are transmitted from a helium-filled chamber at 0.3 K up to room temperature, using coherent fiber optics. A superfluid-tight glass to metal seal is used to seal the fiber optics rod into the cryostat.
A technique for verifying the alignment of large single crystals
Authors: Greiner J. D. , Bailey D. M.
Published: February 2004

A procedure is presented for verifying the alignment of a crystal surface with respect to the x-ray beam in the back-reflection Laue technique. The procedure involves the use of a NaCl reference crystal attached to the surface of interest. Application to the determination of the orientation of a skew surface is discussed.
High pressure intensifier for oxygen use to 4 kilobars
Authors: Betsch Regis J. , White William B.
Published: February 2004

By use of a special steel cylinder and a multilayer Teflon-neoprene Bridgman sealed piston, it is possible to achieve cold oxygen pressures of 4 kilobars—the limit of the remainder of the high pressure system.
Apparatus for determining high pressure coal-hydrogen reaction kinetics under rapid heating conditions
Authors: Anthony D. B. , Howard J. B. , Meissner H. P. , Hottel H. C.
Published: February 2004

A simple and relatively inexpensive method is described for measuring the rate and extent of the reaction of coal with hydrogen under conditions of commercial interest. A thin layer of pulverized coal is supported on an electrically heated metal screen strip capable of initial heating rates of 600–12 000°C/sec followed by extended time at final temperatures of 400–200°C. The device is enclosed in a vessel designed for hydrogen pressures up to 205 atm. Typical results are illustrated and shown to compare favorably with data from previous investigations.
Measurement of the phase fluctuations in a He–Ne Zeeman laser
Authors: Owens D. Kingston , Weiss Rainer
Published: February 2004

The measurement of the phase fluctuations caused by spontaneous emission in the oscillation of a He–Ne laser operating at 1.15 μ is reported. The frequency fluctuations in the signal resulting from heterodyning two independent modes in the laser were measured as f2(ν) =(9.6±2)×10−2 Hz2/Hz for 1.65×107 stored photons per mode and f2(ν) =(2.7±0.3)×10−1 Hz2/Hz for 6.2×106 stored photons per mode. These values are to be compared with the theoretical minima for these cases, which are calculated to be f2(ν) =5.1×10−2 Hz2/Hz and f2(ν) =1.4×10−1 Hz2/Hz, respectively.
A ratio-measurement technique for millimeter wavelength interferometry
Authors: Aitken G. J. M.
Published: February 2004

A three-element radio interferometer can measure the complex ratio of spatial-frequency components in the presence of atmospheric phase fluctuations, even when the interference fringes are badly distorted by the fluctuations. The measurement is based on the principle that the phase-modulated fringes of two interferometers will have essentially identical envelopes if the interferometer baselines are not greatly different. A least-squares fitting process determines the amplitude ratio and phase difference with variances only slightly higher than would be obtained in the absence of phase fluctuations. Three applications of the basic technique to measuring a spatial-frequency spectrum are discussed.
Details of dead time losses in scaling and multiscaling
Authors: Klobuchar R. L. , Ahumada J. J. , Michael J. V. , Karol P. J.
Published: February 2004

An electrometer is employed to investigate dead time effects in scaling and multiscaling. The electrometer method as presented gives accurate values for the dead time over a wide range of counting rates. An expression is also developed for the ``between channel'' dead time of a multiscaler, and a simple method of determining this time is also given. The technique as outlined allows the exact determination of the nonlinearity caused by dead time losses.
A ±15 microdegree temperature controller
Authors: Sarid Dror , Cannell David S.
Published: February 2004

We have constructed a temperature controller utilizing a thermistor in a high impedance ac Wheatstone bridge. It maintains the temperature of a 1.3 liter volume constant to within ±15 μ°C, over a 40 h period. The controller employs a ratio transformer, a simple homemade preamplifier, a commercial lock-in amplifier, a small bipolar power amplifier, and a thermoelectric device. Access to the controlled region can be obtained in a few seconds.
Modification of the Varian XL-100 NMR spectrometer for submilligram natural abundance 13C analyses
Authors: Wilson D. M. , Olsen R. W. , Burlingame A. L.
Published: February 2004

Quadrature detection modifications and a microcell arrangement are described for the Varian XL-100 NMR spectrometer which routinely improve sensitivity in 13C Fourier transform sample-limited studies by a factor of 4–5. The power requirement of the rf pulse amplifier is relaxed by a factor of 4. Previously attainable resolution is not affected.
A simple method for measuring the interface state density
Authors: Nishimatsu Shigeru , Ashikawa Mikio
Published: February 2004

A simple method for measuring interface state density distribution of an MIS capacitor is proposed. The method is the expanded one which is based on comparing a measured quasistatic C-V curve to ideal characteristics. The measurement can be achieved semiautomatically and simultaneously with the quasistatic capacitance measurement by using analog systems. And rather time-consuming computer calculation is not necessary. The completed apparatus can measure the interface state density in the range of 1010−3×1012/cm2· eV for standard Al–SiO2–Si capacitors. It is necessary for precise measurement to determine accurately the doping density of substrate and insulator capacitance.
An easy method to accurately align ion-bombardment guns for depth profiling in Auger electron spectroscopy
Authors: Springer R. W. , Haas T. W. , Grant J. T. , Hooker M. P.
Published: February 2004

A problem with depth profiling in Auger electron spectroscopy is the alignment of the electron and sputter ion beams so that they are coincident on the specimen at the focal point of the analyzer. Most procedures used to date are tedious and require the use of a Faraday cup. The technique reported here allows the direct, precise, and quick alignment of the ion bombardment beam utilizing the optics of the electron spectrometer used for Auger analysis. A typical 2 kV focused ion beam can be aligned within a few minutes using the phenomenon of low energy ion excited Auger electron analysis.
Optimizing ion injection phase in quadrupole mass filters
Authors: Lefaivre D. , Marmet P.
Published: February 2004

It is demonstrated that the absolute transmission of a quadrupole mass filter is improved when the ions are bunched and injected at the proper phase into the instrument. Experiment shows that a rough approximation to the theoretical solution is sufficient to increase the transmission by 125% at high resolution where it is most needed.
Heat pipe as a means of avoiding emergent stem correction for liquid-in-glass thermometers
Authors: Reiss F. E.
Published: February 2004

The emergent stem correction for liquid-in-glass thermometers can be avoided by heating the capillary of the thermometer with a heat pipe to the temperature of the bath. Experiments show that full compensation of the error can be achieved by proper thermometer design.
Coupling scheme and probe damper for pulsed nuclear magnetic resonance single coil probe
Authors: Kisman Kenneth E. , Armstrong Robin L.
Published: February 2004

A coupling scheme and a probe damper for use with a pulsed nuclear magnetic resonance single coil probe are described. The designs for both circuits incorporate the unique properties of PIN diodes. The performances of the circuits at the signal processing level are evaluated at 4.3, 15.78, and 49.0 MHz.
Barium zirconate thermionic cathodes
Authors: Sherman Christopher
Published: February 2004

A clarification of the mechanism responsible for reported high electron emissivities of barium zirconate cathodes in the presence of electronegative gases is made. A suggestion for simplifying the preparation of such cathodes is given.
A sensitive displacement transducer using an extremely reentrant 84 MHz cavity oscillator
Authors: Van Degrift Craig T.
Published: February 2004

A single-turn toroidal optimization of the inductor in the LC circuit of a capacitive displacement transducer is described. It has a higher Q than the usual multiturn coil and allows the construction of a rigid LC resonator which does not use any insulators. When this resonator is used in conjunction with a tunnel diode oscillator, the sensitivity of the capacitor to position changes is conservatively estimated as 7×10−12 cm.
Instrument for measuring maximum thunderstorm electric field intensity
Authors: Vonnegut B. , Rechnitzer B. W.
Published: February 2004

An instrument is described that determines the magnitude of an electric field over a surface by lowering an elevated, grounded, metal point until a corona current ceases to flow from it. Measurements with this apparatus in New Mexico indicate that the maximum thunderstorm electric field over the water surface of a reservoir is considerably larger than that usually encountered over land surfaces.
Photodiode arrays: A convenient tool for laser diagnostics
Authors: Seka W. , Zimmermann J.
Published: February 2004

We report on a variety of useful applications of photodiode arrays in on-line diagnostics of pulsed lasers. These diagnostics include beam cross section monitoring and psec-pulse duration monitoring.
A triaxial rotating vacuum seal
Authors: Packard Richard E. , Williams Gary A.
Published: February 2004

A description is given of three concentric rotating vacuum seals employing reentrant geometry.
Electrical leads for low conductivity measurements under hydrostatic pressure
Authors: Ai Bui , Destruel P. , Giam Hoang The , Loussier R.
Published: February 2004

An electrode system using sapphire for the low conductivity measurement under hydrostatic pressure below 5000 bar is described. The leakage resistance of this design is 1.3×1016Ω at 1000 bar, and 6×1014Ω at 4000 bar.
Multisentis myrmecobius, gen. et. sp. nov. (Acanthocephala: Oligacanthorhynchidae), from the Numbat, Myrmecobius fasciatus, and a Key to Genera of the Oligacanthorhynchidae
Authors: Smales Lesley R.
Published: February 2004

A new genus and a new species of acanthocephalan are described from the numbat
Myrmecobius fasciatus, a termite-eating marsupial from
south-western Australia. Multisentis myrmecobius belongs
to the family Oligacanthorhynchidae and a key to the genera of this family is
given. The life cycle is presumed to involve termites as the intermediate
host. The definitive host-parasite relationship is assumed to have evolved
since the origins of M. fasciatus from ancestral
marsupial forms before the late Miocene.
Dolichopodidae (Diptera) from Papua New Guinea. XIV. Paramedetera, a new genus in the Medeterinae
Authors: Grootaert Patrick , Meuffels Henk J. G.
Published: February 2004

Paramedetera, gen. nov., is described on the basis of
three species: P. papuensis, sp. nov., the type species
from Papua New Guinea, P. sumatrensis, sp. nov., from
the lowlands in West Sumatra, and P. orientalis (Hollis,
1964), comb. nov., from the highlands in West Sumatra.
Paramedetera, gen. nov., is closely allied to
Medetera, but is a more ancestral branch. It is
phylogenetically situated between on one hand Corindia
and Thrypticus and on the other hand
Medetera and Dolichophorus.
The Asian fish tapeworm, Bothriocephalus acheilognathi, in Australian freshwater fishes
Authors: Dove A. D. M. , Cribb T. H. , Mockler S. P. , Lintermans M.
Published: February 2004

Bothriocephalus acheilognathi was collected from 13 of 38 carp (Cyprinus carpio), 2 of 4 mosquito fish (Gambusia holbrooki), and 2 of 12 western carp gudgeon (Hypseleotris klunzingeri ) in waterways of the Australian Capital Territory and New South Wales. This is the first record of this parasite in Australia, and its presence in H. klunzingeri is a new host record. B. acheilognathi presumably arrived in Australia with its introduced fish hosts and has since crossed into native fishes. This cestode may infect other native fish species, a potential that is significant given the high pathogenicity associated with infection in other known hosts.
Flood-mediated changes in aquatic macrophyte community structure
Authors: Nielsen D. L. , Chick A. J.
Published: February 2004

Sixteen artificial billabongs on the floodplain of the River Murray, New South Wales, were surveyed over a 14-month period to observe the effect of different hydrological regimes on the development of aquatic macrophyte communities. The billabongs were initially planted with Vallisneria sp. and Myriophyllum papillosum Orch. in November 1994, then flooded. The 16 billabongs were divided into four treatments: summer flood, spring flood, permanent inundation, and a control treatment that was initially flooded and then allowed to vary in depth with rainfall and evaporation. The plant communities were surveyed on six occasions between April 1995 and June 1996, and percentage cover was estimated on each sampling occasion. Fourteen aquatic macrophyte taxa were recorded over the study period. Billabongs in the permanent and summer treatments exhibited less plant diversity than did billabongs in the control or spring treatments. Terrestrial plants germinated on the exposed areas in both spring and control treatments, but not in the other treatments.
Haemolymph chemistry of tropical rock lobsters (Panulirus ornatus) brought onto a mother ship from a catching dinghy in Torres Strait
Authors: Paterson Brian D. , Grauf Stephen G. , Smith Ross A.
Published: February 2004

For export of live Panulirus ornatus from northern
Queensland, divers catch the lobsters by hand and keep them in small tanks on
dinghies before draining the tanks and returning at speed to a mother ship
that has a larger storage tank. The lobsters are sometimes too weak for
export. The physiological state of lobsters stored in a tank on the mother
ship was studied by measuring the concentrations of L-lactate, D-glucose and
ammonia in the haemolymph. Oxygen levels in the dinghy tanks were normally
acceptable but fell rapidly below 50% saturation when flow was stopped
and the tank was draining. The concentration of lactate in the haemolymph of
lobsters arriving from the dinghy was 16.4 ± 5.7 mmol
L-1 (mean ± s.d.,n =
9); this fell during storage on the mother ship. On the mother ship, serum
concentrations of calcium, potassium and magnesium ions all increased,
haemolymph glucose concentration increased slightly and then decreased, and
ammonia concentration did not change. Future work may identify which aspects
of prior handling are responsible for the elevated lactate concentrations in
captive lobsters, but improvements could be made meanwhile to water flow
through the dinghy tanks.
Live transport and marketing of spiny lobsters in India
Authors: Vijayakumaran M. , Radhakrishnan E. V.
Published: February 2004

Eight species of spiny lobster (six littoral and two deep-sea) and two species
of slipper lobster constitute the lobster fishery of India. Lobster landings
fluctuate around 2000–3000 t annually. High export demand for Indian
spiny lobsters has resulted in regular and organized exploitation, both
inshore and offshore. Almost the entire quantity of lobsters landed in India
is exported in frozen, cooked or live form. Export of live lobsters, which
realize the maximum unit price, has increased from 22 t in 1994 to 97 t in
1996.
Live transport of spiny lobsters has advanced from just keeping them alive for
a few hours in moist intertidal beach sand to the most sophisticated packing
in insulated boxes. The process involves holding the lobsters at the landing
centre and at the city of export. The entire exercise lasts about seven days,
during which period the lobsters are packed twice, each time keeping them out
of water for not less than 20 h. In the holding centres, the lobsters are
often kept at high densities, with the resulting build-up of nitrogenous
wastes and depletion of dissolved oxygen leading to mortalities. Average
mortality is up to 6.5% during live transport.
Delay-difference model to estimate the catch of different categories of the western rock lobster (Panulirus cygnus) for the two stages of the annual fishing season
Authors: Hall Norman G.
Published: February 2004

The annual exploitation rate of the limited-entry rock lobster fishery of
Western Australia is controlled by constraining the total allowable effort. An
important aspect of the harvest strategy introduced in 1993 was the use of
annual levels of allowed fishing effort that could be varied in accordance
with predicted levels of recruitment to the fishery in order to increase the
abundance of spawning females and to reduce the variability in the level of
annual catch. A model was needed that could examine the impact of alternative
management strategies on the catches both within and between fishing seasons.
The model that has been developed uses a delay-difference structure in which
the fishing season is divided into two periods. Growth between the periods,
and over the closed fishing season, is determined from tagging data.
Recruitment is estimated from the observed levels of puerulus settlement. The
model has been fitted to the observed effort within the southern sector of the
fishery. This model allows the evaluation of alternative levels of fishing
effort within the management zone, providing managers and industry with a tool
to explore alternative harvest strategies.
Puerulus of the spiny lobster Panulirus guttatus (Latreille, 1804) (Palinuridae)
Authors: Briones-Fourzán Patricia , McWilliam Paulette S.
Published: February 2004

The puerulus of Panulirus guttatus is described and
compared with that of P. argus, a sympatric species.
Comparative morphological data show that the former has a more specialized
form than the latter and hence is more recent in evolutionary terms. Features
characterizing the puerulus of P. guttatus are its
relatively large size, long spatulate antennae, and well developed sternal
spines. The possible adaptive value of the long spatulate antennae for
selection of specific substrata and/or navigation through inshore waters
is discussed in relation to the ecology of the juvenile and adult phases.
Pueruli of P. guttatus are not found in the surface
collectors, resembling marine vegetation, used to monitor the influx of
pueruli of P. argus into coastal waters on the Caribbean
coast of Mexico. Moreover, small juveniles of
P. guttatus are never found in the natural habitat of
those of P. argus, and large juveniles and adults of
P. guttatus seem restricted to the shallow coral reef
habitat, in contrast to similar phases of P. argus,
which occupy a vast array of habitats and depths throughout their benthic
life. It is hypothesized that the pueruli of both species settle in different
habitats, which would partly explain their sharing of the same geographic
distribution.
Effects of temperature on growth of the Japanese spiny lobster, Panulirus japonicus (V. Siebold) phyllosomas under laboratory conditions
Authors: Matsuda Hirokazu , Yamakawa Takashi
Published: February 2004

The effects of temperature on growth of phyllosomas of the Japanese spiny
lobster Panulirus japonicus were investigated.
Phyllosomas were individually reared at four temperatures (20°, 22°,
24° and 26°C), and intermoult period and moult increment were
monitored. The improved Bêlehrádek’s equation,
G =
aLb
(T–α)c(β–T)d,
was used to describe the relationship between growth characters
(G: intermoult period, moult increment or daily growth
increment), body length (L) and temperature
(T), with a and
b being constants that change at 17·8 mm body
length, c and d being common
constants for all sizes, and α and β being the conceptual biological
lower and upper critical temperatures, which are variables with body length.
The intermoult period increased and the moult increment decreased with
decreasing temperature. However, a negative influence on both the intermoult
period and the moult increment was observed at 26°C for medium-sized and
large phyllosomas. The largest daily growth increment was obtained at 26°C
up to 15·0 mm body length, and then at 24°C. This indicates that
the optimum temperature for growth decreases from 26° to 24°C at
15·0 mm body length. This optimum temperature for growth seemed to be
optimal for survival.
Growth of captive Jasus edwardsii (Hutton) (Crustacea:Palinuridae) in north-eastern New Zealand
Authors: Hooker Simon H. , Jeffs Andrew G. , Creese Robert G. , Sivaguru Kala
Published: February 2004

The relations between growth and mortality rates and water temperature are
important in determining the economic success of spiny lobster aquaculture.
Captive juvenile lobsters (Jasus edwardsii) were grown
at a site in north-eastern New Zealand where ambient sea-water temperatures in
the culture tanks ranged from 23.3°C in summer to 13.4°C in winter,
with an annual mean of 17.2°C (s.d. = 2.8). The growth and
mortality rates of three size classes of juvenile lobsters were examined over
one year in captivity. All lobsters were fed cultured mussels. Lobsters in the
smallest size class grew to an average of 39 mm carapace length (31 g) in
their first year from settlement. Growth to 200 g was estimated to take three
years. Total mortality of lobsters was 12.8% and was greatest in the
0+ size class, for which most mortality occurred in a single tank. Of the
total mortality, 64% occurred during two summer months (January and
February). The growth and mortality of J. edwardsii are
compared with previously unpublished information.
Metamorphosis of the final phyllosoma and secondary lecithotrophy in the puerulus of Panulirus cygnus George: a review
Authors: McWilliam Paulette S. , Phillips Bruce F.
Published: February 2004

The final phyllosoma of Panulirus cygnus metamorphoses
to a non-feeding puerulus that lives on energy reserves accumulated in the
final larva, and the metamorphic moult occurs mainly in the slope region
adjoining the shelf-break off Western Australia. A review of the literature on
field studies, laboratory rearing and nutritional studies of phyllosomal and
other decapod zoeal larvae provided no evidence that metamorphosis in
P. cygnus (or other shallow-water palinurids) is
triggered by a direct environmental cue. It did indicate that metamorphosis
results from the culmination of sustained nutrition and reserve energy levels
through the later larval phase. Therefore, since the puerulus is secondarily
lecithotrophic, it is considered that metamorphosis occurs only after the
final phyllosoma has reached some critical, specific, level of stored energy
reserves. Appropriate food for later larval development and successful
metamorphosis of P. cygnus is more abundant in the
shelf-break region (than further offshore) because this is a region of high
plankton and micronekton biomass dominated by the Leeuwin Current. It also
explains why metamorphosis occurs mainly in the shelf-break region. This
review indicates research necessary for evaluation of the present
interpretation and of larval recruitment processes in this species.
Upwelling tank for culturing rock lobster (Jasus edwardsii) phyllosomas
Authors: Illingworth J. , Tong L. J. , Moss G. A. , Pickering T. D.
Published: February 2004

A tank system for culturing rock lobster
(Jasus edwardsii) phyllosomas is described. Four tanks,
one of which remains empty, are interconnected by ports that allow larvae to
be transferred without handling and the vacated tank to be cleaned. Vertical
water movement in each tank maintains the larvae in suspension, and the
overall design and management allows for feeding with live brine shrimp
(Artemia). Mean survival rates of over 60% to
Stage VIII have been obtained, but only one puerulus has been reared.
Jasus lalandii fishery in post-independence Namibia: monitoring population trends and stock recovery in relation to a variable environment
Authors: Grobler C. A. F. , Noli-Peard K. R.
Published: February 2004

Commercial exploitation of the Namibian Jasus lalandii
stock started in the early 1920s. Catches were high until the mid 1960s, with
annual landings of up to 9000 t. During 1968 and 1969 the minimum legal size
limit was abolished, a collapse occurred in the stock, and annual catches
declined to 1000–3000 t. During a 1988 warm-water event mass mortalities
of lobsters were recorded, and catches continued to decline over the following
three years. In 1992 the total allowable catch (TAC) was set at 100 t, and
finally limited catches. Subsequently, TACs have been kept low and some
fishing grounds have been closed to the industry. Since 1992 the Namibian
lobster research programme has been intensified, incorporating regular
environmental and lobster surveys on the main fishing grounds. During the
environmental surveys, a seasonal cycle in bottom concentrations of dissolved
oxygen observed during the 1980s was confirmed along the southern part of the
Namibian coast. This seasonality in environmental parameters is thought to
contribute to inshore–offshore migrations of the lobster populations and
thus to variable catch rates. Results from commercial and research samples
over the past five years indicate improved recruitment and increased, although
variable, catch per unit effort.
A New Zealand Industry perspective on the Fifth International Conference and Workshop on Lobster Biology and Management
Authors: Sykes Daryl
Published: February 2004

This short article provides an overview of the Conference from the perspective
of an observer from the New Zealand fishing industry. Fishers were well
represented at this Conference. Of special interest to them were the vast
contrasts in lobster fisheries management throughout the world, the apparent
resilience of lobster populations and the similarities in management issues
throughout the world. The Conference emphasized the need for scientists and
fishers to work together, and for industry to have an informed and interactive
role in managing and choosing research directions for lobster resources.
Simulation modelling of capture processes in trap fisheries for clawed lobsters
Authors: Addison Julian T. , Bell Michael C.
Published: February 2004

Lobster stock assessments are difficult because trap catch rates cannot be
assumed to be proportional to abundance. A simulation model has been developed
to consider the factors that might contribute to trap sampling bias. In the
presence of trap saturation due to behavioural interactions at the trap, the
model predicts an asymptotic relationship between catch and density and a
decline in the variance : mean ratio of catch numbers per trap with density. A
random or even distribution of lobsters among traps is predicted despite an
initial aggregated distribution of lobsters on the seabed. Within the range of
parameter values investigated, local depletion around the trap and decline in
bait attractiveness had less influence than behavioural interactions on catch
rates and the distribution of the catch among traps. All these results were,
however, sensitive to assumptions made about the nature of lobster movement on
the seabed. The results have implications for the use of catch data in
assessing stock abundance, and as the pattern of model predictions is
consistent with observed fisheries data, the model is likely to provide a
useful framework for investigating capture processes in trap fisheries for
crustaceans.
Evaluation of a management decision rule for a New Zealand rock lobster substock
Authors: Starr Paul J. , Breen Paul A. , Hilborn Ray H. , Kendrick Terese H.
Published: February 2004

The performance of a proposed management ‘decision rule’–an
algorithm that specifies management actions when specified criteria are
met–was evaluated by exploring the impact of different choices for three
decision-rule parameters on the ability of the rule to achieve management
objectives. To do this, forward simulations from an age-structured assessment
model for the substock of red rock lobster
(Jasus edwardsii) off southern New Zealand were used.
The size of this substock is currently estimated to be about one-third of
BMSY (the level of vulnerable
biomass that would produce maximum sustainable yield), and the management goal
is to rebuild it to BMSY. A target
rebuilding trajectory to BMSY was
generated by allowing the model population to rebuild under the current catch
regime with constant recruitment. The decision rule is based on comparison of
observed catch per unit effort (CPUE) to predicted CPUE.
Process and observation errors, each with a coefficient of variation of
20%, were introduced, and five values were used for each of the three
parameters of the rule. The decision rule was effective in removing all
instances of failure to rebuild and all excessively slow rebuilding
trajectories. The decision rule was also applied to an arbitrarily depressed
starting substock size, and the conclusions were the same.
Potential of a trap-fishery for deep-water rock lobster Palinurus delagoae off South Africa
Authors: Groeneveld J. C. , Cockcroft A. C.
Published: February 2004

An experiment to investigate the potential of a trap-fishery for deep-water
rock lobster Palinurus delagoae was conducted off the
east coast of South Africa between 1994 and 1996. The 75–425 m depth
interval between 27°S and 32°S was stratified according to depth and
latitude, and three regions (North, Central and South) were sampled
systematically over the three years. Sampling by commercial vessels operating
long-lines and traps included an experimental phase (fixed fishing positions)
and a commercial phase (no restriction on fishing location). Generalized
linear models were used to investigate the influence of year, region, sampling
phase, month and soak time. Sampling phase was significant, with traps set
during the commercial phase catching more than those set in the experimental
phase. The effect of soak time on catch rates was not significant. The
almost-50% decrease in the combined abundance index combined with a
marked decrease in mean lobster size over the study period suggests a
relatively low fisheries potential for this species in South African waters;
this may be attributable to the relative scarcity of suitable habitat in the
area.
Age structure of Panulirus ornatus in two habitats in Torres Strait, Australia
Authors: Skewes T. D. , Dennis D. M. , Pitcher C. R. , Long B. G.
Published: February 2004

The lobster population in Torres Strait, Australia, is made up of juvenile and
sub-adult lobsters up to two years old (1+ and 2+), with some
3-year-old (3+) male lobsters. These lobsters live either on shallow
reefs or in the deeper areas between reefs. Intensive surveys of lobsters in
these two habitats showed that 1+ lobsters live only in the deep habitat,
2+ lobsters live in the deep habitat and on shallow reefs, and 3+
male lobsters live mainly on shallow reefs. In the deep habitat, lobsters were
found mainly in areas that had rock and rubble substratum. There may be little
movement of lobsters onto or off the shallow reefs during the winter months
and 1+ lobsters probably recruit onto the shallow reefs so
Mitochondrial DNA phylogeny of red and green rock lobsters (genus Jasus)
Authors: Ovenden J. R. , Booth J. D. , Smolenski A. J.
Published: February 2004

A cladistic analysis of nucleotide substitutions in the
16S ribosomal RNA and cytochrome oxidase subunit I genes
of mitochondrial DNA does not support the monophyly of species within each of
the ‘lalandii’ and
‘frontalis’ subgroups of
Jasus; the subgroupings may need revision. The recently
described species J. caveorum is most closely related to
J. tristani and J. paulensis, and
not to J. frontalis with which it shares an eastern
South Pacific distribution and morphological similarity. Two species,
J. tristani and J. paulensis, are
so genetically similar that further genetic, morphological and behavioural
analyses are needed to assess their status as separate species.
Precision of exploitation-rate estimates in the Tasmanian rock-lobster fishery based on change-in-ratio techniques
Authors: Frusher S. D. , Kennedy R. B. , Gibson I. D.
Published: February 2004

Determination of exploitation rate is considered important for both stock
assessment and establishment of fishery reference points. From 1992 to 1996, a
project was undertaken to evaluate the change-in-ratio technique for
estimating exploitation rates for male lobsters off southern Tasmania.
Confidence limits of exploitation rate estimates were determined by bootstrap
analysis. This showed wide confidence intervals around the estimates for the
fishing years from 1992–93 to 1994–95. Bootstrap analysis was used
to determine the appropriate sample size (number of pot-lifts) for improved
precision in exploitation rate estimates for the 1995–96 fishing year.
Results from field estimates confirm the expected decrease in confidence
intervals. The level of exploitation had an inverse relationship to the
precision of exploitation rate estimates. Relationships can be determined
between the level of exploitation in the fishery and the degree of precision
achievable for a set number of pot-lifts. Thus, sampling programmes can be
designed to minimize cost and provide the degree of precision required for
management strategies.
Recruitment overfishing reference point for the American lobster, Homarus americanus
Authors: Ennis G. P. , Fogarty M. J.
Published: February 2004

A 21-year series of annual estimates of egg production and recruitment in a
Newfoundland lobster population indicates similar asymptotic relationships for
recruitment to the fishery and to the adult population, both derived from
legal stock estimates. Lines with slopes equal to the 90th-percentile and
median survival ratios drawn through the origin of the egg
production–adult recruitment scatterplot were examined as potential
recruitment overfishing reference points for the Arnold’s Cove lobster
stock. If the inverse of the estimated lifetime egg production per recruit
(E/R) for a given exploitation rate exceeds the slope of the selected
reference point, the risk of recruitment overfishing is high. For the
Arnold’s Cove stock, the E/R level at a nominal 90%
exploitation rate is estimated at 4.2% of the unfished population,
compared with 2.5% for the overfishing reference point corresponding to
the median survival ratio. Female lobsters at Arnold’s Cove mature at
sizes below the minimum legal size, providing a buffer against high
exploitation rates. Small, scattered refugia of large lobsters could also help
to explain how heavily exploited populations of this species persist at such a
low level of egg production.
Tectonic plate movements and the evolution of Jasus and Panulirus spiny lobsters (Palinuridae)
Authors: George R. W.
Published: February 2004

Jasus is at least as old as early Miocene (20 Ma).
Genetic differentiation between J. verreauxi in
Australia and New Zealand indicates larval isolation across the northern
Tasman Sea following a northward retreat of a strong south-flowing warm
current. After South Africa and Australia separated from Antarctica, stocks of
the temperate J. lalandii subgroup of three species
became genetically isolated because of reduced larval exchange by tracking of
local environments. Once the full strength of the Antarctic Circumpolar
Current was established, a series of subantarctic islands and seamounts
provided new habitats for four species of the
J. frontalis subgroup, and their larvae responded to
local circulation systems. Speciation of nine species or subspecies of
Indo–West Pacific Panulirus probably occurred
between 9 and 3.5 Ma (late Miocene to early Pliocene) as a result of the
formation of new habitats after collisions of India and Australia with the
Asian plate. Major mountain chains resulted in high continental run-off,
produced regular tropical monsoon systems, enhanced regional upwelling,
altered oceanographic circulation patterns and restricted larval transport
between the Pacific and Indian Oceans.
Enhancement of both cardiac contraction and metabolism by a transient cooling of the lobster Panulirus japonicus
Authors: Kuramoto Taketeru , Tani Masaki
Published: February 2004

Contractile and metabolic activities of the isolated heart of
Panulirus japonicus were recorded while thermal and
hormonal stimuli were applied for 3–6 min. The heart beat was often
augmented in amplitude with a fall in temperature from 20° to
17–15°C. With the augmented beat, a decrease of
pO2 in the ventricle indicated an
increase in oxygen consumption rate of the heart. When serotonin (0.1
µM) and the cold stimulation were applied at the
same time, pO2 in the ventricle
decreased, suggesting that the metabolic rate of the heart markedly rose. In
contrast, octopamine (1 µM) raised the oxygen
consumption rate of the heart only slightly. Octopamine greatly enhanced the
membrane excitability and contraction force of the heart during cold
treatment. A transient period of cooling in vivo may
cause the pericardial organs to release octopamine and serotonin in
P. japonicus. This may be relevant to the care of spiny
lobsters during mariculture, capture, handling and transport.
Estimating lobster recruitment and exploitation rate from landings by weight and numbers and age-specific weights
Authors: McGarvey R. , Matthews J. M. , Prescott J. H.
Published: February 2004

Aprocedure is presented for incorporating catch totals by both weight and
numbers in stock assessment. Their ratio is the weight of an average harvested
individual which, in turn, reflects mean mortality rate. The model is
age-based and requires, as input, a vector of average age-specific weights in
the catch. The model developed for the South Australian rock lobster
(Jasus edwardsii) fishery assumes steady state, constant
fishing mortality on all age classes and a natural mortality rate equal to
0·1. Also explicit are reduced vulnerability of recruitment-aged
lobsters and incidental mortality of lobsters below the legal minimum size.
The solution yields estimates of average exploitation rate and yearly
recruitment. These give (absolute) age-specific population numbers in the
fishable stock. Exploitation rates were estimated for statistical reporting
blocks in South Australia using this catch weight–numbers (qR) method
and, for comparison, that of Beverton and Holt employing mean length. Each
method was also tested with simulated data, the former yielding estimates of
lower variance and bias. In practice, counting individuals captured is likely
to require less time and to yield lower measurement error than measuring
lengths. This method thus offers the possibility for improved precision and
accuracy at lower cost.
Evaluation of effort reduction in the Florida Keys spiny lobster, Panulirus argus, fishery using an age-structured population analysis
Authors: Muller Robert G. , Hunt John H. , Matthews Thomas R. , Sharp William C.
Published: February 2004

A management programme implemented in Florida in 1993 was designed to reduce
the number of traps in the spiny lobster fishery in order to reduce gear
conflicts, environmental damage and effort without reducing harvest. Traps in
the commercial fishery were reduced from 939 000 in 1991 to 568 000 in 1995.
Landings by fishing season, zone (upper Florida Keys and lower Florida Keys),
sex, and time period (summer v. winter) were pro-rated
into numbers by length that were assigned ages by using growth simulations.
From tag–recapture data, moult interval was estimated by using a
logistic regression with terms for zone, sex, time period, carapace length,
and time at large. For lobsters that moulted, the moult increment was modelled
with a multiple regression including the same terms. Standardized
catch-per-trip and total landings increased as traps were reduced.
Age-structured analysis of the catches-at-age indicated that fishing mortality
decreased by 16%, even as landings increased. It is not known whether
the increase in landings was due to natural population fluctuations or to
positive results of trap reduction. Fishing mortality rates still exceed
common benchmarks used in fishery management, and excessive traps remain in
the fishery.
A Community-based Survey of the Koala, Phascolarctos cinereus, in the Eden Region of South-eastern New South Wales
Authors: Lunney Daniel , Esson Carol , Moon Chris , Ellis Murray , Matthews Alison
Published: February 2004

A community-based postal survey (questionnaire and map) was undertaken in the Eden region of south-eastern New South Wales in 1991–92 to help determine the local distribution of koalas and to obtain information on which to base a regional plan of management for koalas. The 1198 replies from the II 600 households in the region represented all parts of the area surveyed. The survey responses suggest that koalas are rare in the Eden region, and that the number of koalas has been constantly low for the last four decades. The records are scattered both chronologically and geographically. National Parks and Nature Reserves have never been the stronghold of local koala populations, and freehold land, particularly farmland, is not a major reservoir of koalas. Most koalas reported were in, or adjacent to, State Forests, particularly Murrah–Berrnagui and Tantawangalo–Glenbog–Yurammie. These areas appear to contain the core of the surviving koala population of the region. An assessment of the vegetation where koalas were sighted indicated that dry forest is the preferred habitat. The once abundant and widespread local koala population of late last century has been reduced by habitat loss and fragmentation to a few small, isolated populations. This regional survey, which was undertaken by use of a carefully constructed questionnaire, revealed an invaluable source of records and contributed 70% of the records in the database used for this study. This study also laid a basis for assessing koala management options in south-eastern New South Wales.
Male Bias in Road-kills of Macropods
Authors: Coulson Graeme
Published: February 2004

I determined the sex of a total of 251 road-kills of six macropod species in southern Australia over a 13-year period. There was a significant bias towards males in five species, ranging from 65 to 92% males, but there was no difference from parity in the red kangaroo, Macropus rufus. Male eastern grey kangaroos, M. giganteus, and male western grey kangaroos, M. fuliginosus, probably behave in ways that expose them to vehicles more than females. Male-biased road-kills of swamp wallabies, Wallabia bicolor, may reflect skewed population sex ratios. There are insufficient data on the behaviour and population structure of the red-necked wallaby, M. rufogriseus, and rufous-bellied pademelon, Thylogale billardierii, to determine which explanation is responsible for male-biased road mortality in these species.
An ELISA for epidemiological studies of myxomatosis: persistence of antibodies to myxoma virus in European rabbits (Oryctolagus cuniculus)
Authors: Kerr P. J.
Published: February 2004

An ELISA (enzyme-linked immunosorbent assay) for detecting antibodies to myxoma virus was characterised in wild rabbits for use in epidemiological studies. Virus neutralisation assays and virus challenge were used to define sera from rabbits as positive or negative for myxoma-virus antibodies. In a group of naturally infected wild rabbits, antibodies to myxoma virus were readily detectable by ELISA each month for at least 12 months in all rabbits, including those where neutralising antibodies could no longer be detected. Maternally transferred antibodies could be detected in kittens born to immune does for approximately six weeks after birth. IgM antibodies to myxoma virus were detected by ELISA only during the active disease and recovery phase of myxomatosis. The ratio of IgM : IgG at a standard serum dilution provided an index of time since infection and a confirmatory assay for early myxomatosis, because the detection of IgM corresponded approximately with the onset of clinical signs. Rabbit antibodies to the orthopoxvirus, vaccinia, did not cross-react in the ELISA.
Production of homoplasmic xenomitochondrial mice
Authors: McKenzie Matthew , Trounce Ian A. , Cassar Carolyn A. , Pinkert Carl A.
Published: February 2004

The unique features of mtDNA, together with the lack of a wide range of mouse cell mtDNA mutants, have hampered the creation of mtDNA mutant mice. To overcome these barriers mitochondrial defects were created by introducing mitochondria from different mouse species into
Mus musculus domesticus
(Mm) mtDNA-less (ρ
0
) L cells. Introduction of the closely related
Mus spretus
(Ms) or the more divergent
Mus dunni
(Md) mitochondria resulted in xenocybrids exhibiting grossly normal respiratory function, but mild metabolic deficiencies, with 2- and 2.5-fold increases in lactate production compared with controls. The transfer of this model from
in vitro
to
in vivo
studies was achieved by introducing Ms and Md mitochondria into rhodamine-6G-treated Mm mouse embryonic stem (ES) cells. The resultant xenocybrid ES cells remained pluripotent, and live-born chimerae were produced from both Ms and Md xenocybrid ES cells. Founder chimeric females (G
0
) were mated with successful germ-line transmission of Ms or Md mtDNA to homoplasmic G
1
offspring. These xenocybrid models represent the first viable transmitochondrial mice with homoplasmic replacement of endogenous mtDNA and confirm the feasibility of producing mitochondrial defects in mice by using a xenomitochondrial approach.