Interview with Mulyoto Pangestu

Mulyoto Pangestu is an Indonesian who studied in Melbourne on two occasions; in 1993-1996, and in 1998-2005. During his first period of study he started at the University of Melbourne, but transferred to Monash University in 1994. He completed a Graduate Diploma in Agricultural Science in his one year at Melbourne University, before completing his Masters in Reproductive Science at Monash in 1994-1996. The change in field was the reason for his transferral to Monash. After two and a half years back in Indonesia, he returned to Monash University to complete his PhD in Reproductive Science. He was awarded Australian International Development Assistance Bureau (AIDAB) Scholarships to study in Australia. The interview was conducted in English on 18 August 2014 by Dr. Jemma Purdey of Deakin University. This set comprises: an interview recording, a timed summary and a photograph.

Microscopic modifications of the female reproductive tissues of Mustelus antarcticus

The ovarian follicles and oviducal glands have structural organisations similar to other chondrichthyans. Sperm are stored in the oviducal gland of all maturing and mature animals throughout the year and throughout pregnancy. Microscopic features of the uterine epithelium suggest nutrients are supplied to developing embryos without placenta formation.

Reproductive performance and egg and larval quality of the blacklip abalone

The study highlights the interrelationship between physical characteristics of female broodstock with reproductive performance, egg quality and subsequent larval success, and reproductive seasonality of the blacklip abalone (Haliotis rubra Leach). Suitable indices for assessing broodstock were developed. Seasonal changes in biochemical compositions in relation to maturation and development was discussed.

Asynchrony and regional differences in the reproductive cycle of the greenback stingaree Urolophus viridis from south-eastern Australia

Determining the periodicity of the reproductive cycle in chondrichthyan species when the population is recruiting asynchronously, as found for Urolopus viridis, can be problematic. The reproductive cycle generally requires distinguishable trends in reproductive indices across the population. The present study utilised other similar and sympatric urolophid species with synchronous reproductive cycles. Through data collected in the present study and comparisons of maximum total length (TL), periodicity of egg and embryo in utero, ovarian cycles, largest ovarian follicle diameter, and matrotrophic contribution (percentage increase from egg to embryo after maternal histotroph supplement) from similar studies, an annual reproductive cycle can be hypothesised. Sampling across two separate regions of Lakes Entrance (LE) and Western Bass Strait (WBS), U. viridis also showed regionality in several of the reproductive indices. Maximum TL and mass for females, mean size-at-birth, and female size-at-maturity and size-at-maternity in LE were markedly smaller than in WBS. In both regions litter size (1–2) increased with TL, with an exception of one female in WBS producing a litter of 3 which could be attributed to the larger TL. The implication of U. viridis producing such few young annually is they have the lowest biological productivity of any urolophid species in south-eastern Australia.

Influence of environmental conditions on foraging behaviour and its consequences on reproductive performance in little penguins

During the breeding season, seabirds are central place foragers and have to adapt their foraging behaviour in response to environmental variation to maximize efficiency and reproductive output. Due to its small size and swimming mode of transport, the little penguin (Eudyptula minor) is expected to be greatly susceptible to such fluctuations. The links between local-, meso- and macro-scale environmental conditions and inter-annual variation in foraging behaviour and reproductive performance of little penguins were investigated during three consecutive breeding seasons at two colonies in south-eastern Australia marked by contrasting oceanographic conditions. At a local scale, foraging effort was correlated positively with wind direction and negatively with wave height. At a regional scale, foraging effort of individuals from both colonies was negatively correlated with higher sea surface temperature (SST) off the Bonney Coast in the previous Austral summer, suggesting a weaker Bonney Upwelling event and a cascade of effects throughout the Bass Strait region. At a larger scale, the El Niño Southern Oscillation was also found to correlate with foraging behaviour, with lower foraging effort being observed during La Niña event. Although individuals increased their foraging effort during years with poorer conditions, they were not able to maintain high breeding success. In addition, peak egg-laying was found to coincide with a decrease in local SST and a peak of sea surface chlorophyll-a concentration. In conclusion, these results highlight how different environmental conditions could influence foraging behaviour and ultimately reproductive success of little penguins. It also showed that under certain circumstances, these individual strategies were not sufficient to cope with environmental variability.

Foraging strategies and reproductive success in two sympatric seabird species: influence of environmental variability

 This work focused on flexibility in foraging strategies in little penguins and short-tailed shearwaters, which represents an important mechanism enabling them to cope with highly dynamic ecosystems and provides a buffer against spatial and temporal changes in prey availability over the breeding period.

Repeated acute activation of the hypothalamo-pituitary adrenal axis prior to and during estrus did not affect reproductive performance in gilts

We investigated the effects of repeated acute activation of the hypothalamo-pituitary adrenal axis, prior to and during estrus, on reproduction in gilts. Individual gilts (n = 24 per treatment) either served as controls or were subjected to daily acute stress ("negative handling," brief electric shock with a battery-operated prodder during confinement with the experimenter) commencing, on average, 8 days prior to estrus. Gilts subjected to negative handling had a significant elevation in plasma concentrations of cortisol that lasted at least 3-4 h, and these gilts were slower than control gilts to approach and interact with the experimenter in a standard test. Nevertheless, reproductive performance--as measured by sexual receptivity and proceptivity, ovulation, the percentage of gilts that became pregnant, the number of embryos 20-21 days after insemination, and the weight of embryos--was not affected by repeated acute activation of the hypothalamo-pituitary adrenal axis. Our results suggest that repeated acute activation of the hypothalamo-pituitary adrenal axis prior to and during estrus does not affect the factors that control estrus and ovulation in gilts.

Reproductive cycle of Urolophus cruciatus in south-eastern Australia: does the species exhibit obligate or facultative diapause?

Observations of synchronous rapid growth of embryos and ovarian follicles in pregnant females during the half-year December–May leading to parturition, ovulation, mating, and fertilization suggest Urolophus cruciatus has the capacity for an annual reproductive cycle. Conversely, the higher proportion of the pregnant females in the population carrying eggs than carrying embryos in utero during December–May and all pregnant females in the population only carrying eggs in utero during June–November indicate a longer reproductive cycle. Analysis based on the usual assumptions implies that the species most likely exhibits a biennial cycle with ~18-month period of diapause following ovulation prior to ~6-month period of rapid embryogenesis. However, it is feasible that the period of the cycle is triennial with ~30-month period of diapause or alternatively diapause varies among individuals and varies from year to year. Rather than exhibiting a fixed-term reproductive cycle where obligatory diapause leads to parturition timed every year to provide favourable conditions for neonates, as suggested for several other chondrichthyan species, U. cruciatus may exhibit facultative diapause where the period of diapause and hence the reproductive cycle varies depending on the prevailing environmental conditions or density-dependent factors as described for many terrestrial species. U. cruciatus is highly matrotrophic (>4000 % wet mass gain from ovum to full-term embryo), litter size (1–4) increases with maternal length, sex ratio among embryos is 1:1, and male breeding condition varies seasonally with peak sperm production coinciding with female ovulation.