bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of green fluorescent protein to visualize rice root colonization by Azospirillum irakense and A. brasilense
Authors: Zhu Guo-Yu , Dobbelaere Sofie , Vanderleyden Jos
Published: March 2003

To visualize rice root colonization by two Azospirillum species, A. irakense KBC1 was equipped with a plasmid expressing the enhanced green fluorescent protein (EGFP) and A. brasilense Sp7 was equipped with a plasmid expressing the enhanced yellow fluorescent protein (EYFP). In both cases, intensive fluorescence was observed under the epifluorescent microscope. Striking differences for association with roots of rice seedlings were observed between the two species: (i) A. irakense cells attached faster than A. brasilense to rice roots following inoculation; (ii) A. irakense attached to rice roots as vibroid cells, while A. brasilense occurred as rounded cyst-like cells; (iii) A. irakense cells were mainly found on root hairs, whereas A. brasilense cells were mainly concentrated on root surfaces. The two Azospirillum species obviously do not compete with each other for colonization of rice roots. These results demonstrate that the two Azospirillum species differ in their mode of rice root colonization. As�the two Azospirillum species are extensively studied for unravelling mechanisms of plant root colonization and plant growth promotion, labelling with fluorescent protein is a useful additional tool for these studies.
Production of reactive oxygen species during non-specific elicitation, non-host resistance and field resistance expression in cultured tobacco cells
Authors: Able Amanda J. , Sutherland Mark W. , Guest David I.
Published: March 2003

We examined production of reactive oxygen species (ROS) and induction of cell death in tissue-cultured tobacco cells undergoing different disease resistance responses. A superoxide-dependent hypersensitive response occurs during both the race-specific resistance response of tobacco cells challenged with incompatible zoospores of Phytophthora nicotianae and during non-specific elicitation of tobacco cells challenged with Phytophthora glucan elicitors extracted from the fungal cell wall. Inhibition studies are consistent with dependence upon endogenous Ca2+ levels, and with involvement of NAD(P)H oxidase and peroxidases in production of ROS during both specific and non-specific elicitation. The patterns of resistance expression during non-host resistance or field resistance responses appear to be similar to race-specific resistance expression with regard to the timing and order of events. However, the intensity of the response is very much reduced. In contrast, during non-specific elicitation, these temporal patterns are significantly altered. The differences in timing, intensity and extent of responses during different modes of disease resistance expression indicate that stimulation of cultured plant cells with non-specific soluble fractions in order to model in planta events during plant / Oomycete and, by implication, plant / fungal interactions, has significant limitations.
Differential expression of 5-enol-pyruvyl-shikimate-3-phosphate synthase isoforms in elicitor-treated, cultured maize cells
Authors: Forlani Giuseppe
Published: March 2003

The expression of two 5-enol-pyruvyl-shikimate-3-phosphate synthase (EC 2.5.1.19) isoforms was investigated in Zea mays L. suspension-cultured cells following exposure to a fungal elicitor. Activity levels of isozyme II specifically increased soon after treatment, in strict connection with induction of phenylalanine ammonia-lyase (PAL) and attainment of a new free-phenylalanine homeostasis at a higher concentration. However, a few days later, activity of the other enzyme form was also significantly enhanced, concomitant with a sharp rise in overall amino acid content, a further increase in PAL level and a resumption of cell lysis. Besides strengthening the hypothesis that an entire set of genes encoding for shikimate pathway enzymes (whose expression is specifically involved in plant dynamic defence) may exist, a general change in the levels of several amino acids seems to point towards a reprogramming of their metabolism in elicited cells.
Elevated chloroplastic glutathione reductase activities decrease chilling-induced photoinhibition by increasing rates of photochemistry, but not thermal energy dissipation, in transgenic cotton
Authors: Kornyeyev Dmytro , Logan Barry A. , Payton Paxton R. , Allen Randy D. , Holaday A. Scott
Published: March 2003

The effect of the overproduction of glutathione reductase (GR+) in cotton (Gossypium hirsutum L. cv.�Coker 312) chloroplasts on the response of photosynthetic parameters to chilling in the light was examined. After 180 min at 10°C and 500 μmol photons m–2 s–1 in the chamber of an oxygen electrode, leaf discs of GR+ plants exhibited lower levels of sustained PSII photoinhibition than leaf discs of wild-type plants. No genotypic differences in thermal energy dissipation, leaf pigment composition, or the dynamics of xanthophyll cycle de-epoxidation were observed. The rate of induction and steady-state levels of photochemistry were greater for GR+ in comparison to wild-type plants. Enhanced photochemistry in GR+ plants could not be attributed to higher rates of CO2 assimilation at 10°C. Although GR overproduction afforded some increased protection against PSI photoinactivation, suggesting improved scavenging of reactive oxygen species, higher PSI activities could not completely explain the greater rates of photochemistry. Pools of glutathione and ascorbate were significantly more reduced in GR+ plants. Increased demand for reducing power to maintain these constituents in the reduced state may contribute to the higher rates of photochemistry observed in GR+ plants.
On the importance of including soil nutrient feedback effects for predicting ecosystem carbon exchange
Authors: Kirschbaum Miko U. F. , Simioni Guillaume , Medlyn Belinda E. , McMurtrie Ross E.
Published: March 2003

To grow, plants need both carbon, which is fixed in photosynthesis, and inorganic nutrients, which are generally obtained from the soil. Much interest currently exists in trying to understand the uptake and storage of carbon by terrestrial ecosystems. This paper investigates to what extent carbon gain and storage are modified by soil nutrient availability. This issue is investigated in relation to both short-term carbon fluxes on the time scale of interannual variability and long-term ecosystem carbon stocks on time scales of several thousand years.We conclude from simulations with an ecosystem model (CenW) that interannual variations in carbon gain can be significantly affected by feedback effects through the nutrient cycle. This feedback effect operates principally through an imbalance between carbon and nutrient dynamics. In years that allow high carbon gain, nutrient supply typically does not match the increased carbon supply so that foliar nutrient concentrations are reduced. This lowers productivity below that which could be expected if foliar nutrient concentration remained the same. The importance of these feedback effects is shown to be greatest at intermediate levels of water availability and nutrient supply, and is relatively more important for net ecosystem carbon exchange than for net primary production.We conclude that the long-term build-up of carbon stocks in ecosystems is often controlled by the rate at which nutrients can be gained. This conclusion is based on data from published studies showing that the slow build-up of carbon matches the gain in nitrogen, phosphorus and sulfur, and on our simulations of system carbon stocks in response to fertiliser addition.The paper concludes with a discussion of the importance and feasibility of including these processes into models at different scales, including the broad continental scale. For modelling net ecosystem exchange for Australia, it is regarded as feasible and desirable to use models that are constrained by these system-internal feedback effects. Such models have already been used for large-scale simulations in Australia and other countries.
Influence of nitrogen and phosphorus supply on foliage growth and internal recycling of nitrogen in conifer seedlings (Prumnopitys ferruginea)
Authors: Carswell Fiona E. , Millard Peter , Rogers Graeme N. D. , Whitehead David
Published: March 2003

The dynamics of internal cycling of nitrogen were studied in the southern hemisphere conifer miro [Prumnopitys ferruginea (G. Benn. ex D. Don) de Laub.], which has an indeterminate growth habit. In a 2-year experiment, P. ferruginea seedlings were supplied with nutrient solutions consisting of two different concentrations of nitrogen (5 and 0.5 mM) and phosphorus (1.33 and 0.133 mM) in the first year, and two concentrations (5 and 0.5�mM) of a 15N-labelled nitrogen solution in the second year. Growth and nitrogen content of new foliage were shown to be largely dependent on seedling nitrogen status at the end of the first year, and only weakly dependent on nutrient supply in the second. An average of 70% of total nitrogen in new foliage was remobilised from storage in the first 63 d after flushing began. The remainder of new-foliage nitrogen was derived by root uptake from the nutrient supply in the second year. There was some response of nitrogen uptake to high nitrogen supply in the second year where seedlings had been nitrogen deficient at the end of the first year. However, it was concluded that the indeterminate growth habit of P. ferruginea did not distinguish its pattern of nitrogen storage and remobilisation from that of determinate conifers.
The maize epicuticular wax layer provides UV protection
Authors: Long Lacy M. , Patel H. Prinal , Cory Wendy C. , Stapleton Ann E.
Published: March 2003

As surface ultraviolet-B (UV-B) radiation levels increase due to the decline in the protective stratospheric ozone layer, ultraviolet radiation sunscreens will become more important for all plant species that grow in sunlight. Epicuticular waxes, which cover the aerial portions of all terrestrial plants, are ideally located to be sunscreens. The sun-screening ability of maize (Zea mays L.) epicuticular waxes was tested using the glossy1 mutant, which is specifically defective in juvenile wax production. A significant difference between the glossy1 mutant and wild type was seen in UV-induced leaf rolling and in some measurements of UV-induced DNA damage levels under enhanced UV. Isolated epicuticular wax layers absorbed significant amounts of UV, and leaves with wax absorbed more UV than leaves with little wax. Thus, by some measures, the epicuticular waxy layer acts as an ultraviolet radiation protectant in maize.
Review: Metabolome characterisation in plant system analysis
Authors: Fernie Alisdair R.
Published: March 2003

Plant biology, like all other fields of biology, has undergone a major transition in the last few years. With increasing access to ever-improving technologies, the reductionist approach is being augmented or replaced by holistic, system based approaches. In plant species, this transition has been greatly facilitated both by completion of the Arabidopsis genome sequence and development of novel tools to generate and characterise genetic diversity. Following these advances, the focus of plant genetic research has shifted from sequencing and identification of genes to functional characterisation of gene products. The tools currently being adopted to ensure as comprehensive a description of either environmental or genetic perturbations of biological systems as possible range from relatively simple morphological analyses to the more complex analytical profiling of mRNA transcripts, protein or metabolites. In this review, methods of high-throughput metabolite analysis are highlighted, with particular emphasis on those that allow determination of steady-state concentrations of a broad spectrum of metabolites. In addition, possibilities of adopting metabolic flux analytical techniques from medicinal and microbial sciences for the study of plant systems are discussed. Finally, I attempt to define future prospects for metabolome analyses within the wider context of systems biology.
Hydraulic and chemical signals in the control of leaf expansion and stomatal conductance in soybean exposed to drought stress
Authors: Liu Fulai , Jensen Christian Richardt , Andersen Mathias Neumann
Published: March 2003

Both hydraulic and chemical signals are probably important in regulating leaf growth and stomatal conductance of soybean (Glycine max L. Merr.) under drought stress. However, until now they have not been investigated concomitantly in this species. To explore this, a pot experiment in a temperature-regulated greenhouse was conducted, in which plants were subjected to progressive drought during early reproductive stages. Biophysical parameters, viz. relative leaf expansion rate, stomatal conductance, leaf turgor, leaf [ABA], xylem pH and xylem [ABA] were followed in control and stressed plants. Drought stress decreased relative leaf expansion rate, stomatal conductance and leaf turgor, whereas it increased leaf [ABA], xylem pH and xylem [ABA]. As soil dried, significant differences between water treatments for relative leaf expansion rate, stomatal conductance, leaf turgor, leaf [ABA], xylem pH and xylem [ABA] were observed at 14, 9, 14, 14, 14 and 9 d after imposition of stress, respectively. The relationships of relative values for relative leaf expansion rate, stomatal conductance, leaf turgor, leaf [ABA] and xylem pH to the fraction of transpirable soil water (FTSW) were well described by linear-plateau functions that allowed calculation of the soil-water thresholds at which processes in stressed plants began to diverge from well-watered controls. The soil-water threshold for stomatal conductance (0.64) was significantly higher than that for relative leaf expansion rate (0.29), xylem pH (0.28), leaf [ABA] (0.27) and leaf turgor (0.25). Relative xylem [ABA] increased, first linearly (when FTSW > 0.5) and then exponentially (when FTSW < 0.5) with decreasing FTSW. Relative stomatal conductance decreased exponentially with increasing relative xylem [ABA] (r2=0.98). Decreased stomatal conductance coincided with an increase in xylem [ABA] and occurred before any significant change of leaf turgor could be detected, indicating that chemical signals (seemingly root-originated ABA) control stomatal behaviour at moderate soil water deficits. Relative relative leaf expansion rate was linearly correlated with relative leaf turgor (r2=0.93), relative xylem pH (r2=0.97) and relative leaf [ABA] (r2=0.98), implying that both hydraulic and chemical signals were probably involved in regulation of leaf expansion at severe soil water deficits.
Michael George Pitman 19332000
Authors: Boardman Keith , Osmond C. Barry , Lüttge Ulrich
Published: March 2003

The Pitmans were a prolific west England family with Sir Isaac Pitman, the inventor of shorthand, the most famous member. During the 1800s four members of different branches of the family emigrated to Australia, but Michael's branch remained in Bristol. His great-grandfather Samuel William Pitman owned and operated a pork butcher's shop in Bedminster, Bristol. The eldest of his 12 children was George Pitman, Michael's grandfather. George worked first as a draper but later established his own pork butcher's shop at the other end of Bedminster. The elder of his two sons, Percy George, was Michael's father. Both sons were involved in running the shop. In 1930 Percy George married Norma Ethel Payne, who was trained and worked as a milliner. Her father (Gubby to Michael) was a skilled wood-worker who was employed as a pattern maker. Michael spent much time with Gubby and learnt from him wood-working and handyman skills.

Michael, the eldest of three boys, was born on 7 February 1933 at the family home in Clift Street, Ashton. The family's financial situation became difficult and by the time the second son was born, the family had moved to cramped quarters over the shop in Bedminster. In those days a pork butcher made and cooked his own smallgoods, boiling up the pigs' cheeks and trotters and making the brawn. Each year at Christmas, Michael's mother would use the big boilers to cook batches of 20 Christmas puddings as gifts for favoured customers and business associates. Michael brought her 1932 recipe for 20�puddings to Australia, and when he was Professor of Biology at Sydney University he made small puddings for his staff in the Pitman family tradition.
John Robert Booker 19421998
Authors: Carter J. P. , Poulos H. G. , Tanner R. I.
Published: March 2003

Professor John Robert Booker died in Concord Hospital in Sydney on 13 January 1998, after a long and courageously-fought battle against cancer. His death cut short a brilliant academic career and deprived the Australian geotechnical and engineering mechanics communities of one of its most eminent members.

At the time of his death John Booker held a personal chair in engineering mechanics in the Department of Civil Engineering at the University of Sydney, and he was widely regarded as one of the finest researchers of his generation working in the field of theoretical geomechanics. His long battle with cancer did not deflect him from his life's work. While understandably, he was unable to hold formal classes during the last months of his life, it is significant that he was active in research until his very last weeks, such was his love for and dedication to his work.

John Booker was a warm, friendly, caring man who touched many lives. He was mentor to most with whom he came into close contact, students and colleagues alike. He is survived by his second wife Elizabeth, daughters from his first marriage, Katie and Lucie, sister Judith and mother Joan.
False Start for the PhD in Australia
Authors: Rae Ian D.
Published: March 2003

When the PhD was introduced in England, consideration was also being given to its introduction in Australia. The University of Melbourne first discussed the idea in 1918, and again in 1924, but other Australian universities were opposed. Arguments ran along lines familiar in England — some foresaw the PhD competing with other doctoral degrees, and others saw difficulties in providing resources. Others wished to continue the system whereby Australian graduates went to Britain for research training. Faced with a unanimous verdict by its sister institutions, Melbourne withdrew its proposal, and the idea of the PhD went underground, not to surface again until 1944 when Melbourne again led the way, this time successfully, in its introduction.
Andrew Crowther Hurley 19261988
Authors: Maslen V. W.
Published: March 2003

Andrew Hurley was a distinguished theoretical chemist, noted for his clear insights, which he was always ready to share, and for his mathematical ingenuity. His career spanned what in many ways was the defining era of computational quantum chemistry.
The millipede genus Metopidiothrix Attems (Diplopoda : Chordeumatida : Metopidiotrichidae)
Authors: Shear William A.
Published: March 2003

The millipede genus Metopidiothrix Attems, 1907 (Chordeumatida : Heterochordeumatoidea : Metopidiotrichidae), of south-east Asia, is examined and 30 new species (M. abuyog, M. anderssoni, M. apoensis, M. baletei, M. baybay, M. burckhardti, M. calamei, M. cameronensis, M. danao, M. dolok, M. gallus, M. gressetti, M. hoogsraali, M. kagpili, M. kalang, M. laguna, M. layang, M. lehtineni, M. leyte, M. loebli, M. mada, M. matang, M. mujong, M. nebulosa, M. samuelsonorum, M. santubong, M. schawalleri, M. sedgwicki, M. visca, M. werneri) are added to the genus. The synonymy of M. javana Chamberlin under M. lacertosa Attems is confirmed. Notes are provided on natural history, biogeography and taxonomic characters. The family Metopidiotrichidae is closely related to the Heterochordeumatidae. A key to the genera of Metopidiotrichidae is presented. The family is divided for the first time into three subfamilies: Metopidiotrichinae Attems contains Metopidiothrix and Reginaterreuma Mauriès, 1987; Neocambrisomatinae Mauriès (new status) includes Neocambrisoma Mauriès, 1987, Australeuma Golovatch, 1987, Nesiothrix Shear & Mesibov, 1997 and Nipponothrix Shear & Tanabe, 1994; and Schedotrigoninae Mauriès (new status) includes only Schedotrigona Silvestri, 1903.
Revision of Coronostrongylus (Nematoda : Strongyloidea) parasitic in the stomachs of macropodid marsupials
Authors: Beveridge I.
Published: March 2003

The monotypic nematode genus Coronostrongylus Johnston & Mawson, 1939 from the stomachs of macropodid marsupials was reviewed and was found to consist of a least seven closely related species. Coronostrongylus coronatus Johnston & Mawson, 1939 is found most commonly in Macropus rufogriseus, but occurs occasionally in M. dorsalis, M. parryi and Petrogale inornata. Coronostrongylus johnsoni, sp. nov. is most commonly found in M. dorsalis, but occurs also in M. rufogriseus, M. parma, Thylogale stigmatica, Petrogale godmani and P. brachyotis. Coronostrongylus barkeri, sp. nov. is most prevalent in Onychogalea unguifera, but occurs also in M. rufus, M. robustus and P. brachyotis. Coronostrongylus closei, sp. nov. is restricted to Petrogale persephone. Coronostrongylus sharmani, sp. nov. occurs only in rock wallabies from eastern Australia: P.�coenensis, P. godmani and P. mareeba; C. spratti, sp. nov. occurs in P. inornata and P. assimilis. Coronostrongylus spearei, sp. nov. is restricted to Papua New Guinea where it is found in Dorcopsulus vanhearni, Dorcopsis hageni and D. muelleri. Although all of the nematode species occur in one principal host species or a series of closely related host species, occurrences in geographically disjunct areas and in phylogenetically distant hosts are features of C. coronatus, C. barkeri, sp. nov. and C. johnsoni, sp. nov. The occurrence of seven closely related nematode species found in a wide range of macropodid host species is more readily accounted for by a hypothesis involving multiple colonisations of hosts than by the hypothesis of co-speciation.
Molecular phylogeny of the mud lobsters and mud shrimps (Crustacea : Decapoda : Thalassinidea) using nuclear 18S rDNA and mitochondrial 16S rDNA
Authors: Tudge C. C. , Cunningham C. W.
Published: March 2003

Partial sequences of the 18S nuclear and 16S mitochondrial ribosomal genes were obtained for 14�species of thalassinidean shrimp (families Callianassidae, Laomediidae, Strahlaxiidae, Thalassinidae and Upogebiidae) and a further six species in related decapod infraorders (families Aeglidae, Astacidae, Lithodidae, Palinuridae, Raninidae and Scyllaridae). Maximum-likelihood and Bayesian analyses show equivocal support for the monophyly of the Thalassinidea, but show strong support for division of the infraorder into two major clades. This dichotomy separates representatives in the Upogebiidae, Laomediidae and Thalassinidae from those in the Strahlaxiidae and Callianassidae. The Laomediidae is shown to be paraphyletic, with the thalassinid species, Thalassina squamifera, being placed on a branch between Axianassa and a clade comprising Jaxea and Laomedia, the three current laomediid genera. For a monophyletic Laomediidae, the family Axianassidae should be resurrected for the genus Axianassa.
Revision of Sceliages Westwood, a millipede-eating genus of southern African dung beetles (Coleoptera : Scarabaeidae)
Authors: Forgie Shaun A. , Grebennikov Vasily V. , Scholtz Clarke H.
Published: March 2003

The genus Sceliages Westwood (Scarabaeinae : Scarabaeini) from southern Africa is revised. Seven species are recognised: Sc. granulatus, sp. nov. (Botswana, South Africa), Sc. augias Gillet (Angola, Democratic Republic of Congo, Zambia), Sc. adamastor (Le Peletier de Saint-Fargeau & Serville) (South Africa), Sc. brittoni zur Strassen (South Africa), Sc. difficilis zur Strassen (South Africa, Zimbabwe), Sc. gagates Shipp (South Africa, Moçambique) and Sc. hippias Westwood (South Africa). The new species is described and the others are redescribed. Neotypes are assigned to Sc. adamastor and Sc. gagates. A key to the species is provided and male genitalia and other diagnostic characters are illustrated. A phylogenetic analysis of the genus is presented. Distribution maps of all species are provided. Mature larvae of Sc. hippias are described, the first for the genus. They can be distinguished from other Scarabaeinae larvae by a markedly reduced torma on the epipharynx and complete absence of hypopharyngeal sclerites (oncyli). Millipede relocation and burial behaviour of the adults of Sc. hippias and Sc. adamastor are described. We also provide descriptions of the brood chamber and brood balls of Sc. hippias.
A new genus and species of sea pen (Octocorallia : Pennatulacea : Stachyptilidae) from the Antarctic Peninsula
Authors: López-González Pablo J. , Williams Gary C.
Published: March 2003

Only six of the thirty-three valid genera of sea pens have previously been recorded from the Southern Oceans (Subantarctic and Antarctic regions). The discovery of a new genus, Gilibelemnon, and new species, Gilibelemnon octodentatum, of stachyptilid sea pen is here reported from the South Shetland Islands, which makes a total of eight genera known to occur in the Southern Oceans and thirty-four genera of sea pens known worldwide. Diagnostic features of the new genus are described, including the presence of a clearly delimited dorsal and ventral naked track on the rachis, the calyces with eight long terminal teeth, the siphonozooids densely and irregularly distributed and the presence of three-flanged rods in the peduncle surface. A discussion of sea pen phylogeny and biogeography in the Antarctic region is also provided.
Longfin eels need reserves: modelling the effects of commercial harvest on stocks of New Zealand eels
Authors: Hoyle Simon D. , Jellyman Don J.
Published: March 2003

Freshwater eels in New Zealand are heavily exploited by the commercial fishery and, to a lesser extent, by customary fisheries. A model was developed to investigate the effect of the New Zealand commercial eel fishery on escapement of migrating longfin (Anguilla dieffenbachii) and shortfin (A. australis) eels. Exploitation rates of 5% and 10% per year reduced the spawning per recruit of A. dieffenbachii females by 83% and 96.5%, respectively, below unexploited levels. The model suggests that New Zealand longfin eels may be severely recruitment overfished and only absence of fishing in some productive areas is likely to be effective in maintaining at least 50% of spawning per recruit. Being younger at spawning, eels are less susceptible to overfishing. Using the current minimum legal weight (220 g), the spawning per recruit of A. australis females was reduced by only 48% at an exploitation rate of 10% per year.
Moulting growth of the Australian giant crab, Pseudocarcinus gigas
Authors: McGarvey Richard , Levings Andrew H. , Matthews Janet M.
Published: March 2003

The growth of Australian giant crabs, Pseudocarcinus gigas, has not been previously studied. A tagging program was undertaken in four Australian states where the species is subject to commercial exploitation. Fishers reported a recapture sample of 1372 females and 383 males from commercial harvest, of which 190 females and 160 males had moulted at least once. Broad-scale modes of growth increment were readily identified and interpreted as 0 , 1 and 2 moults during time at large. Single-moult increments were normally distributed for six of seven data sets. Moult increments were constant with length for males and declined slowly for three of four female data sets. Seasonality of moulting in South Australia was inferred from monthly proportions captured with newly moulted shells. Female moulting peaked strongly in winter (June and July). Males moult in summer (November and December). Intermoult period estimates for P. gigas varied from 3 to 4 years for juvenile males and females (80–120 mm carapace length, CL), with rapid lengthening in time between moulting events to approximately seven years for females and four and a half years for males at legal minimum length of 150 mm CL. New moulting growth estimation methods include a generalization of the anniversary method for estimating intermoult period that uses (rather than rejects) most capture–recapture data and a multiple likelihood method for assigning recaptures to their most probable number of moults during time at large.
Growth in eight species of tropical anchovy determined from primary otolith increments
Authors: Hoedt Frank E.
Published: March 2003

Growth in eight species of tropical anchovy from Townsville, North Queensland was analysed from counts of primary growth increments in the sagittal otolith. Experimental validation of growth increment periodicity in four species indicated that primary growth increments are deposited daily. Reparameterized von Bertalanffy growth equations were used to describe the relationship between length and age over the range of lengths aged in all species. Growth rate during the immature phase ranged from 0.4 to 0.7 mm d–1 with an average of 0.58 mm d–1. Longevity was estimated for four stolephorid anchovies and ranged from three to ten months. The short lifespan and high values of the growth constant, K, calculated for the smaller species of anchovy were consistent with other recent otolith-based studies on small tropical clupeoids. This paper reports the first study of large number of co-occurring closely related tropical anchovy species and evidence that growth increments are formed with a daily periodicity.
Family- and species-level biotic indices for macroinvertebrates of wetlands on the Swan Coastal Plain, Western Australia
Authors: Chessman Bruce C. , Trayler Kerry M. , Davis Jennifer A.
Published: March 2003

SWAMPS (Swan Wetlands Aquatic Macroinvertebrate Pollution Sensitivity) was developed as a biotic index for wetlands near Perth, Western Australia. Numerical grades between 1 and 100 were assigned to wetland macroinvertebrate taxa, generally at the family and species levels, to reflect the sensitivities of these taxa to anthropogenic disturbance, primarily nutrient enrichment. Index scores for individual wetlands were calculated as abundance-weighted or unweighted means of the grades of all taxa present in standard samples. Scores calculated at both the family and species levels showed a strong correlation with independent measures of cultural eutrophication and other anthropogenic disturbances, but such correlations were generally higher for the species-level index. The species index also discriminated more between individual wetlands. SWAMPS should be useful in routine and rapid assessment and monitoring of wetland condition in the Perth region and could be easily adapted to other regions and continents.
Effects of exploitation by two co-existing fleets on the bluefish, Pomatomus saltatrix, in southern Brazil: an application of a seasonal catch-at-age model
Authors: Lucena Flávia M. , O'Brien Carl M. , Reis Enir G.
Published: March 2003

This paper describes 20 years in the exploitation of the bluefish, Pomatomus saltatrix, in southern Brazil and investigates the effects of the commercial fleets on stock structure. Port samples were obtained from the commercial fisheries based at Rio Grande do Sul for the period 1992–1998. In addition, data derived from the exploitation during the period 1977–1983 (Krug and Haimovici 1991) were included in this analysis. A statistical catch-at-age model is proposed to estimate population size and exploitation rates for both periods of study. This model incorporates both the seasonal characteristic and multi-fleet nature of the P. saltatrix fishery. During the most recent time period, fishery mortality has increased and spawning stock biomass has reduced in comparison to the earlier period 1977–1983. Currently, the exploitation of P. saltatrix relies on fish of all age classes. Adults have been intensively exploited and juveniles may not be abundant enough to maintain the stock at the current high level of exploitation. Management options for the stock are presented based on a redistribution of effort between fleets. Simulations indicate that a ban on fishing in shallow waters for either one or both gears would restore the level of spawning stock biomass.
Zooplankton assemblages and hydrography in the spawning area of anchovy (Engraulis anchoita) off Río de la Plata estuary (Argentina - Uruguay)
Authors: Viñas María Delia , Negri Rubén M. , Ramírez Fernando C. , Hernández Daniel
Published: March 2003

The massive spawning of anchovy (Engraulis anchoita) in Argentine waters takes place in spring in the coastal sector off the Buenos Aires Province, with the highest concentrations of spawners occurring in front of the Río de la Plata mouth. In October 1995, the size structure, composition and abundance of the zooplankton community was analyzed and related to the hydrography and the abundance of anchovy eggs. Oceanographic conditions were different from the recorded means for the season. A higher proportion of the colder and more saline shelf waters were present in the coastal area and strong haloclines were not observed. High values of plankton biomass were observed in the estuarine frontal area and in the weakly stratified waters of the median shelf. The cluster analysis of the stations gave rise to the formation of coastal (CA), transitional (TA) and shelf (SA) faunistic areas. Mesozooplankton smaller than 1 mm total length (TL) dominated the whole area. The copepods, Paracalanus spp. and Oithona similis, and the cladocerans, Evadne nordmanni and Podon spp., constituted the bulk of this mesozooplankton fraction. Oithona similis was the dominant species in the SA. The copepod, Acartia tonsa (1–2 mm TL), was extremely abundant in the estuarine front (more than 17 600 individuals m–3) followed by appendicularians, members of Pseudocalanidae, anchovy eggs and decapod larvae. Species of Calanidae (Calanoides carinatus and Calanus simillimus), the amphipod hyperiid, Themisto gaudichaudii, and the euphausiid, Euphausia lucens, largely dominated the macrozooplankton (>2 mm TL) in the TA and SA. In the CA, significant positive correlations between the abundance of small copepods (size ranges <1 and 1–2 mm) and anchovy eggs were found. Trophic implications of these findings for first-feeding anchovy larvae were discussed. The adequacy of the TA and SA as feeding ground for adults of anchovy was evaluated.
Seasonal and interannual variations in diatom assemblages in Murray River connected wetlands in north-west Victoria, Australia
Authors: Gell Peter A. , Sluiter Ian R. , Fluin Jennie
Published: March 2003

Epipelic diatom assemblages collected from three wetlands connected to the Murray River displayed considerable variation in response to flooding and drying phases. Murray River water input usually generated diatom assemblages dominated by Aulacoseira species. After isolation, the diatom flora of two wetlands shifted to assemblages of small Fragilariaceae forms. Elevated nutrient levels corresponded with the appearance of eutraphentic taxa such as Cyclotella meneghiniana, Eolimna subminuscula, Luticola mutica and Nitzschia palea. Further evapoconcentration induced shifts to taxa tolerant of elevated salinity levels including Amphora coffeaeformis, Navicula incertata, Staurophora salina and Tryblionella hungarica. Ordination analyses reveal a strong chemical control on the diatom taxa present in the wetlands, in accordance with known ecological preferences for salinity and nutrients. The influence of nitrogen and phosphorus concentrations in controlling diatom assemblages was subordinate to salinity once conductivity values exceeded 1400 μS cm–1. The results of such biomonitoring provide a means of interpreting wetland history from fossil assemblages contained in sediment sequences.
Sex difference in liver-oil concentration in the deep-sea shark, Centroscymnus coelolepis
Authors: Hernández-Pérez Margarita , Rabanal Gallego Rosa M. , González Carlos Mª José
Published: March 2003

Percentages of liver oil, squalene in oil and squalene in liver from fifty-seven individuals of Centroscymnus coelolepis, a deep-sea shark from the North African Atlantic Ocean near Tenerife (Canary Island), were measured. The percentages were in the range of 46.9–93.9 for liver oil, 35.5–62.2 for squalene in oil and 21.5–48.5 for squalene in liver. The liver-oil and squalene contents were related to the sex, maturity, size and catch depth of the sharks. Sex had a clear influence on the concentration of squalene levels found. Samples separated into two groups, according to their sex, when principal component analysis (PCA) was applied. Centroscymnus coelolepis males have greater economic value than females because they are easier to capture and have the highest squalene content.Resumen. Se han medido los porcentajes de aceite y escualeno contenidos en el hígado de 57 tiburones del género Centroscymnus coelolepis, capturados en aguas profundas del Océano Atlántico, cerca de Tenerife (Islas Canarias). Los porcentajes oscilaron entre 46.9 y 83.9 de aceite en hígado; 37.5 y 62.2 de escualeno en aceite y 21.5 y 48.5 de escualeno en hígado. Se ha relacionado el sexo, la madurez, tama�o y profundidad de pesca de los tiburones con el contenido en aceite y escualeno. Los resultados han mostrado que el sexo tiene una clara influencia en la proporción de este último. Cuando se aplicó el análisis de componentes principales (PCA), las muestras se separaron en dos grupos de acuerdo con su sexo.
Population structure, movement and habitat preferences of the purple-spotted gudgeon, Mogurnda adspersa
Authors: Boxall George D. , Sandberg John J. , Kroon Frederieke J.
Published: March 2003

We examined the movement patterns and habitat preferences of Mogurnda adspersa in Pattersons Creek, a small, low-order, rainforest creek in Gillies Range State Forest, Far North Queensland, Australia. First, we conducted a capture and recapture study to document population structure and individual movements. Our results show that movement is a prominent feature of population behaviour of M. adspersa, with male gudgeons moving significantly more between pools than females, irrespective of gudgeon size. Second, we quantitatively described habitat characteristics of rainforest pools using point sampling. This data was then combined with capture data to describe the habitat preference of M. adspersa. Our results show that the number of gudgeons was positively related to pool size and decreased with increasing pool velocity. We discuss the results in light of effective management options for the species habitat in general, and Far North Queensland in particular.
Replacement of littoral native vegetation with the ponded pasture grass Hymenachne amplexicaulis: effects on plant, macroinvertebrate and fish biodiversity of backwaters in the Fitzroy River, Central Queensland, Australia
Authors: Houston Wayne A. , Duivenvoorden Leo J.
Published: March 2003

Changes in plant and macroinvertebrate communities were found following replacement of extensive zones of floating-attached/submergent native vegetation within Fitzroy River backwaters by the major environmental weed Hymenachne amplexicaulis (Poaceae). Impacts of H. amplexicaulis on native littoral flora and fauna (macroinvertebrates and fish) were assessed by comparing three sites previously supporting native vegetation and now invaded by H. amplexicaulis with nearby stands of native backwater vegetation. Plant biomass of Hymenachne plant beds was 30-fold greater than native plant beds, whereas plant species diversity (richness) was significantly less. Macroinvertebrate communities of Hymenachne beds were significantly lower in abundance of insect orders Ephemeroptera, Hemiptera and Odonata, while Coleoptera were more abundant in Hymenachne beds. Non-metric multidimensional scaling ordination of macroinvertebrate family abundance and composition data showed that Hymenachne plant beds had a different assemblage to that in native plant beds. In common with other studies of weed invasions, an increased abundance of some vertebrate fauna was observed (in this case an introduced fish species Xiphophorus maculatus comprised 75% of fish captured in Hymenachne beds compared with 0% in native plant beds). Change in vegetation structure was implicated as an important factor influencing macroinvertebrate and fish faunal composition, and with potential to impact on waterbird habitat values of wetlands.
Estimated growth of the mud crab Scylla olivacea in the Ranong mangrove ecosystem, Thailand, based on a tagging and recapture study
Authors: Moser S. M. , Macintosh D. J. , Pripanapong S. , Tongdee N.
Published: March 2003

Growth of the mud crab Scylla olivacea in the Ranong mangrove ecosystem was estimated using a size-transition matrix. Male (n = 1284) and female (n = 1069) mud crabs were tagged with externally visible and numbered T-tags and then released. Tagged crabs caught by commercial small-scale fishermen were measured and re-released. Data from 664 male and 463 female recaptures were obtained in total. Moult increment in the investigated size range (5–13 cm external carapace width) was independent of size and sex. The size distribution of mud crab moult increments was fitted to a normal distribution, resulting in a mean moult increment of 1.67 ± 0.48 cm (s.d.). This result was used to estimate the proportion of males and females moulting, and the selectivity of the baited traps used to catch them. Trap selectivity among the tagged crabs was uniform for both male and female crabs. Also, the proportion of those moulting decreased with size in the same manner for both sexes. The predictions of growth from the final size-transition matrix were in agreement with the observed growth of a subset of tagged crabs not used in the estimation of parameters in the size-transition matrix and growth of crabs reared in captivity over a period of 2 months.
Position affects gastropod predation of sessile colonizers on a tropical rocky shore
Authors: Coates Mike
Published: March 2003

A long-term experiment was carried out to determine the relative abilities of five sessile animals to colonize cleared plots in the presence or absence of predators. The experiment was done on two adjacent rocky shores, one sheltered and one exposed, on a small tropical island. The effect of predation in maintaining bare space was greatest on the exposed shore/upper mid-intertidal, less on the sheltered shore and absent on the exposed shore/lower mid-intertidal. The barnacle, Tesseropora rosea, recruited heavily at the exposed shore/lower mid-intertidal and was dominant, but was unable to colonize the exposed shore/upper mid-intertidal or the sheltered shore. The barnacle, Tetraclita squamosa, successfully colonized only the exposed shore/upper mid-intertidal and did not appear to be affected by predation. The oyster, Saccostrea amasa, had low colonization levels only on the sheltered shore and exposed shore/upper mid-intertidal, small individuals were susceptible to predation. The barnacle, Chthamalus maylayensis, heavily colonized only the exposed shore/upper mid-intertidal but was removed from this shore height by gastropod predators. The oyster, Saccostrea echinata, colonized only the sheltered shore and was very susceptible to predation. Given the variability found on this small spatial scale, it is suggested that consistent differences in ecological processes between regions (tropical versus temperate) are unlikely but, rather, that differences between localities will be found at the level of species interactions and abiotic effects in particular habits.
Extensive genetic divergence among populations of the Australian freshwater fish, Pseudomugil signifer (Pseudomugilidae), at different hierarchical scales
Authors: McGlashan Dugald J. , Hughes Jane M.
Published: March 2003

The 'island' nature of river systems limits the possibility of dispersal in freshwater fish species, with many displaying extensive genetic subdivision across their ranges. We examined the population genetic structure of the predominantly freshwater fish, Pseudomugil signifer, at fine, medium and broad scales using allozyme and mitochondrial DNA techniques. Extensive genetic subdivision across the range (FST = 0.6) at six polymorphic allozyme loci was partitioned mostly among river-system drainages (42%). Patterns of mitochondrial DNA sequences, which mirrored previous taxonomic designations and a terrestrial biogeographic barrier, identified two major groups. The level of divergence between the groups implied a considerable period of isolation. At a more localized scale, significant genetic differences between adjacent drainages implied that flood events are not effective transport mechanisms and indicate that populations of P. signifer in different drainages are essentially independent units. The history of P.�signifer appears to be dominated, at different spatial scales, by long periods of isolation among drainages mediated by changes in sea-level, which merge and isolate drainages haphazardly over time. The chance nature of dispersal, coupled with isolation and potential population size fluctuations, probably leads to the observed complex patterns of genetic divergence.
Spatial and habitat-related patterns of temperate reef fish assemblages: implications for the design of Marine Protected Areas
Authors: Curley Belinda G. , Kingsford Michael J. , Gillanders Bronwyn M.
Published: March 2003

Patterns of rocky reef fish assemblages (composition and relative abundance of species) were examined to provide data on the design of Marine Protected Areas (MPAs), which aim to protect these organisms. A hierarchical design was used to investigate changes in fish assemblages at scales of metres to kilometres along-shore, and among reef habitat types within two 10-km areas on the central coast of New South Wales, Australia. Influences of physical and biological attributes of a reef on assemblages of fish were also examined. The greatest variation in fish assemblages occurred at scales of 2–6 km along-shore. Eighty percent of species recorded were found within a 6-km section of coastline. The most predictable differences in assemblages were found between reef habitats (urchin-grazed barrens, Ecklonia forest and sponge habitat), and between depths. Marine Protected Areas should ideally incorporate all available habitats over the entire depth range at which they occur. This may require MPAs larger than 2–6 km, or multiple MPAs that have been specifically located to include these features, as representation of habitats was found to vary at scales of kilometres to tens of kilometres along shore.
The foraging ecology of two sympatric fur seal species, Arctocephalus gazella and Arctocephalus tropicalis, at Macquarie Island during the austral summer
Authors: Robinson S. A. , Goldsworthy S. G. , Hoff J. van den , Hindell M. A.
Published: March 2003

Antarctic Arctocephalus gazella and subantarctic Arctocephalus tropicalis fur seals breed sympatrically at Macquarie Island. The two species have different lactation strategies, the former rearing its pup in 4 months and the latter taking 10 months. The diet and at-sea foraging behaviour of these sympatric species was compared during the austral summer period when their pup rearing period overlapped. The prey of the two fur seal species was very similar, with fish dominating the diet. The myctophid, Electrona subaspera, was the main prey item (93.9%) in all months of the study. There were no major differences in the diving behaviour between species. Both species foraged north of the island parallel to the Macquarie Ridge. Foraging activity was concentrated at two sites: (i) within 30�km north of the island; and (ii) at 60 km north. Most locations for overnight foraging trips were within 10 km of the colonies. The different lactation strategies of A. gazella and A. tropicalis allowed for flexibility in foraging behaviour. At Macquarie Island, the local marine environmental conditions have resulted in similar foraging behaviour for both species.