Identification of a putative egg-laying hormone in neural and ovarian tissues of the black tiger shrimp, Penaeus monodon, using immunocytochemistry

The existence of an egg-laying hormone (ELH) was identified for the first time in the black tiger shrimp, Penaeus monodon, by means of immunoenzyme and immunofluorescence techniques. This was achieved using a polyclonal antibody produced against expressed recombinant ELH of the female Australian blacklip abalone, Haliotis rubra. The shrimp ELH reactive material was found to be localised within female neurosecretory tissues and the secretory tissue of the antennal gland, but was not identified in the X-organ sinus gland within the eyestalk. It was also present in the ovary, where the amount of ELH present was observed to be greatest in the period prior to spawning. These findings implied that the induction of P. monodon spawning might be involved with humoral regulation relating to ELH expression.

Estimating population size of the black-eared miner, with an assessment of landscape-scale habitat requirements

The decline of the Black-eared Miner Manorina melanotis has been caused primarily by habitat degradation and vegetation clearance. To better direct conservation actions for this species there was a need to assess habitat requirements on a regional-scale and to estimate the population size using quantitative methods. We used vegetation mapping and the current distribution of the Black-eared Miner to determine regional-scale habitat requirements. These findings were combined with the results of distance sampling to provide population estimates. The species is restricted to large tracts of intact mallee in the Murray Mallee of southeastern Australia that have not been burnt for at least 45 years. The density· of Black-eared Miners is highest in areas that are dominated by mallee- Triodia associations and have not been intensively grazed. The Bookmark Biosphere Reserve supports an estimated 501 (270-927, 95% CI) colonies, containing 3758 (2026-6954) phenotypically pure Black-eared Miners, 2255 (1 215-4170) hybrids and small numbers of Yellow-throated Miners Manorina flavigula. However, the effective population size is considerably smaller (390 Black-eared Miners '(21 0-726) and 234 hybrids (126-433)), due to a skewed adult sex ratio (1 female: 1.81 males) and complex social organization. A smaller population also persists in the Murray Sunset National Park containing 53 (32-85) Black-eared Miner/hybrid colonies. Both populations face a high risk of extinction from large-scale wildfire. The endangered status of the species under IUCN criteria remains warranted.

Methods for aging and sexing the Black-eared Miner, Manorina melanotis, and Yellow-throated Miner, M. flavigula

Morphometric data on 92 Black-eared Miners and 47 Yellow-throated Miners that had been independently sexed using molecular techniques were analysed to investigate size dimorphism between the sexes. We found that both species are sexually dimorphic in size, with males being the larger sex. Discriminant analyses of morphometric data were used to develop a simple method for sexing both species in the hand. Additionally, alula shape was consistent with other methods that we applied for ageing individuals. Sex-specific size differences between Black-eared and Yellow-throated Miners detected here add further support to the contention that they represent different taxa. The application of these sexing and ageing techniques for both species of mallee miner will improve ongoing field management of the endangered Black-eared Miner.

Translocation of the socially complex black-eared miner manorina melanotis: a trial using hard and soft release techniques

We translocated five colonies of the highly social and co-operatively breeding Black-eared Miner Manorina melanotis, an endangered Australian honeyeater. Two colonies were released immediately (hard release) and two colonies were housed in aviaries for up to a week on-site and then supplied with food for a further week following release (soft release). A fifth colony was released using a combination of methods. All four hard and soft released colonies contained dependent fledglings at the time of release. This appears to be the first translocation of a co-operative species where intact colonies containing multiple breeding females, each with a suite of helpers have been translocated successfully. Both hard and soft release treatments appeared equally successful during an initial monitoring period of up to two months. All four colonies maintained social cohesion, and displayed high levels of survival and site fidelity. Both hard release and one soft release colony attempted to breed within 600 m of their release site within eight weeks of release. The other soft release colony bred 12 months later. We believe the inclusion of dependent young in each translocated colony provided a focus for translocated colonies that promoted site faithfulness and colony cohesion. Results of long-term monitoring remain inconclusive and it is recommended that monitoring be repeated during several future breeding events. Given our findings, we recommend that when translocating highly social species every effort is made to translocate the entire group, hard release techniques be applied and stimuli that enhance group cohesion and site faithfulness (the presence of dependent young) be exploited.

Intraspecific phenotypic variability in the black-eared miner (Manorina melanotis); human-facilitated introgression and the consequences for an endangered taxon

Prior to this study the circumscription of the endangered black-eared miner (Manorina melanotis) and the common yellow-throated miner (Manorina flavigula) has been clouded by the existence of hybrid individuals. We examined the intra- and inter-specific phenotypic variation of the two taxa. All available museum specimens (n=138) and a sample of live individuals (n=83) were examined. Cluster analysis revealed a continuum of phenotypic traits now exists between the two taxa. However, further analysis revealed the black-eared miner and yellow-throated miner were separable on phenotypic characters prior to extensive modification of mallee habitat after 1950, suggesting the black-eared miner should be afforded full species status [contrary to Schodde and Mason, 1999. (Schodde, R., Mason, I.J., 1999. The Directory of Australian Birds: Passerines. CSIRO Wildlife and Ecology, Canberra]. Our study highlights the need to carefully examine, not only intraspecific phenoptyic variation within a taxon, but to also consider how such variation may be affected by hybridisation facilitated by human disturbance of habitat.

Mapping the Australian archaic: reflections on black medea

Wesley Enoch’s Black Medea is explicit about what is, and what is not, its project: the chorus implores the audience not to read the narrative of its infanticidal heroine as one that demonises black women. Instead, the play affirms that its narrative can be understood differently and in a way that has a wider social significance. Taking my cue from the claim that the story is somehow ‘about everyone,’ I would like to begin unravelling the play’s relevance to contemporary contentions of Australian and indeed ‘Unaustralian’ subjectivity, particularly in relation to the discourses that seek to construct ‘Australian’ identity through an appeal to antiquity and what I describe as ‘the archaic.’ It seems to me that Black Medea presents an opportunity for thinking about the ways in which the discourses of aboriginal and classical antiquity operate to inform contemporary, contesting definitions of Australian identity. Regardless of whether these discourses of antiquity are claimed as ‘Australian’ or abjected as Other or ‘Unaustralian’ – and they have been used in both ways – they remain, I argue, formative to current conceptions of Australian identity and are positioned in the economy of discourses that comprise that arena. As will be seen, the mixed reception or ambivalence with which these complementary discourses of antiquity are treated in Australian culture gives Black Medea the potential to be situated among them in subversive and questioning ways, and in ways that may highlight the reasons for their ambivalent status.

How to start the first tutorial

This guide has been written for people who are new to tutoring in the Faculty of Economics and Commerce at the University of Melbourne. It is one of a number of teaching and related guides provided by the Teaching and Learning Unit (TLU).
The guide is intended to be a useful source of ideas and advice for good tutoring practice, based on sound educational principles and research.

The effect of hook/bait size and angling technique on the hooking location and the catch of recreationally caught black bream Acanthopagrus butcheri

The black bream Acanthopagrus butcheri recreational fishery is the largest estuarine fishery in Victoria. This fishery is managed through legal-minimum length and daily bag limits. The success of this management strategy requires a high survival rate for released fish. Deep-hooking is known to reduce the chance of fish survival after recreational capture and release. This study investigated the potential to reduce deep-hooking and the number of under-size A. butcheri caught by varying angling gear and techniques. Three sizes of long shank hook (small [size 8], medium [size 4] and large [size 1/0]) and two angling techniques (slack line and tight line) were tested for their deep-hooking rates and selectivity characteristics. Increasing the hook size from small to large decreased the likelihood of deep-hooking by 6.6 times (95% CI 2.3–16.3 times). Fishing with a tight line instead of a slack line decreased the chance of deep-hooking by almost 100% (95% CI 0.8–3.6). Fishing with a large hook instead of a small hook significantly (F = 6.71, df = 2, P = <0.001) increased the mean A. butcheri length, although this mean size increase was less than 1 cm. This study was able to identify angling gear and angling technique manipulations that reduced the rate of deep-hooking when targeting A. butcheri in Victorian estuaries.