Abalone culture - a new business opportunity

There are about 100 species of abalone in the world, but only 20 are of high commercial importance. In the Philippines, the abalone species are Haliotis asinina, H. varia, H. ovina and H.glabra, but it is the former which has high commercial value. The semi-processed abalone are frozen, dried or canned for export to many countries. An outline is given of the major aquaculture activities and duration of breeding and culture. Abalone hatchery production operations and investment costs and returns are detailed. Particular reference is made to the modular system of abalone culture in floating cages.

Dynamic changes of total bacteria and Vibrio in an integrated seaweed-abalone culture system

Polyculture of seaweeds alongside fed animal aquaculture is an environmentally friendly means of avoiding eutrophication problem both in land-based and sea-based monoculture systems. Many aspects of such polyculture systems have been described, but little attention has been given to the impact of live seaweeds on the microbiological properties of the water that connects the algae and animals. In this investigation, the Pacific red alga Gracilaria textorii was cultured in a recirculated dual tank system (150 L) with the juvenile abalone Haliotis discus hannai. Dynamic changes of total bacteria (TB) and total Vibrio (TV) in the water of polyculture and monoculture systems were evaluated. Results revealed that (1) level of TB in the polyculture was constantly higher than in the monoculture over a 6.5-day period. While levels of TV in the polyculture was detected to be constantly lower than in the monoculture, (2) integration of G. textorii in the abalone culture changed the Vibrio compositions in the water as judged by the changes of bacteria colony types; (3) application of artificial diet led to dramatic increase of the levels in TB and TV in both systems at 12 h after application in the 24-h test and resulted in selective propagation of Vibrio in the water in the monoculture system; (4) polyculture of G. textorii with juvenile abalone in combination with feeding with live algal diet helped to maintain low levels of TV and the balance of the Vibrio composition; (5) living biomass of G. textorii was effective in preventing propagation of two purified Vibrio strains (V alginolaticus and V logei) in the water. These results provide a general basis of the dynamic changes of levels in TB and TV in a seaweed-abalone polyculture system with or without artificial diet in tanks. (c) 2005 Elsevier B.V All rights reserved.

Investigation of abalone mitochondrial DNA and new applications

The work developed and applied new mitochondrial DNA markers to abalone aquaculture and wild fisheries. The number of markers and their success in the areas applied were all firsts in the abalone industry. The work will contribute to the future sustainability of this resource in culture and in the wild.

Seasonal variations of total lipid and fatty acid contents in muscle, gonad and digestive glands of farmed jade tiger hybrid abalone in Australia

The lipid and fatty acid (FA) contents of muscle, gonad and digestive glands (DG) of Jade Tiger hybrid abalone were studied over the four seasons. Higher contents of total lipid and saturated fatty acids (SFA) were found in summer from muscle. For gonad the higher total lipid content was found in summer and spring whereas the SFA content peaked in summer only. For DG the higher contents of total lipid and SFA were recorded in all seasons except autumn. Winter samples showed significantly higher content of PUFA in all three types of tissue. High contents of eicosapentaenoic acid (EPA, 20:5 n−3), docosapentaenoic acid (DPA, 22:5 n−3) and docosahexaenoic acid (DHA, 22:6 n−3) were recorded in winter from muscle, although no marked variations were observed from gonad. For DG the high content of DHA was also observed in winter whilst EPA and DPA maintained high levels in all seasons except summer.

Environmental site assessment for abalone ranching on artificial reef

This study investigated the feasibility of ranching the abalone Haliotis rubra (Leach) and Haliotis laevigata (Donovan) on concrete artificial reefs at a site chosen by industry investors on silty bottom off Altona Beach, Port Phillip Bay, Victoria, Australia. The study started from the premise that artificial reef deployment combined with abalone stock enhancement may achieve the dual purpose of habitat and stock improvement. It evaluated the hydrodynamics of the site in relation to artificial reef structural stability and drift algal transport, the development and ecology of the artificial reef assemblage, and abalone enhancement by seeding the reefs with hatchery juvenile abalone and transplanting adult broodstock abalone. Despite a scarcity of reports on culturing abalone on artificial reef, a literature review examined broadly the functions of artificial reefs, particularly in the context of abalone enhancement, and the relationship between artificial reefs, hydrodynamics and ecology. The major finding was that the success of artificial reef projects is highly dependent on the environment of the chosen site, and that preliminary studies are essential to predict their likely success. This consideration alone provided strong justification to undertake this study. The topography at the Altona site was generally flat, with natural patches of low basalt boulder reef, offering low habitat complexity, yet supporting a diverse range of flora and fauna, including a low-density wild stock of H. rubra. Water depth was a mean of 3.3 m at low tide and 4.4 m at high tide. A single, uncomplicated, concrete artificial reef of H-shape design, was tested as abalone habitat. The hydrodynamic analysis confirmed previous studies of Port Phillip Bay, with mild current speeds of mean 0.045 m.s-1, and maximum-modelled wave height (H1/3) of 1.21 m and period (T1/3) of 4.51 sec. Water temperature ranged from 9.9şC during July to 23.8şC during January, with salinity averaging of 35.5 ppt. The site had a low probability of receiving drift algae, necessary as a food source for abalone, because of its geographic location, potentially affecting ranch productivity. Ecological monitoring of the three-year old artificial reef shows complex changes in the flora and fauna over time, particularly in respect of the sessile fauna. Key differences between the artificial reef and a nearby natural reef community were: lower cover of corallines and late colonisers, such as sponges. High levels of sedimentation were recorded at the Altona site. Hatchery juvenile H. laevigata, with mean survival of 15% after two years and a mean annual growth rate of 39 mm, showed the most promise for outplanting. In comparison, for hatchery juvenile H. rubra, mean survival was 9% after three years and mean annual growth rate was 22 mm. No natural recruitment of H. laevigata was recorded on artificial reef despite transplants of adult broodstock on the reefs. Natural recruitment of H. rubra was also low and insufficient to reliably contribute to abalone ranch stock. Having examined the hydrodynamic, ecological and enhancement attributes of the Altona site, the study concluded that the site was marginally viable for abalone ranching, and that an alternative site near Werribee, 20 km further southwest, had superior attributes for growth and survival of abalone.

Effects of the initial size, stocking density and sorting on the growth of juvenile Pacific abalone, Haliotis discus hannai Ino

During winter months, a novel overwintering mode of transferring juvenile abalones to open seawaters in southern China rather than keeping them in closed land-based nursery systems in northern China is a popular practice. The initial size, stocking density and sorting are among the first considerations when establishing an abalone culture system. This study aimed to investigate the effects of these factors on the growth of juvenile Pacific abalone, Haliotis discus hannai Ino, during overwintering. Juvenile abalones were reared in multi-tier basket form for overwintering in open seawaters in southern China for 106 days. The daily growth rates (DGRs) in the shell length of all experimental groups ranged from 67.08 to 135.75 mu m day(-1), while the specific growth rates (SGRs) were 0.2447-0.3259% day(-1). Variance analysis indicated that both DGRs and SGRs in shell length were significantly affected by the initial body size and stocking density. Furthermore, the effects of stocking density on DGRs and SGRs varied with the initial size. However, sorting abalones according to their initial sizes may not be necessary in practice as sorting did not alter growth significantly at all densities in this study. Factors potentially affecting abalone growth such as genetic control and intraspecific competition were discussed.

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.

Molecular genetic markers for abalone aquaculture

Describes the development and mapping of molecular markers in the blacklip and greenlip abalones. By means of a genome scan using a novel selective DNA pooling strategy, markers associated with growth were discovered that could potentially be applied to increase genetic gain in abalone aquaculture, whilst minimising inbreeding.

Raunch culture goes to school? : young women, normative femininities and elite education

Public concern about popular culture’s sexualisation of women and girls is regularly voiced in the Australian media. Young women grow up against a backdrop of ‘raunch culture’ (Levy, 2005), which for some scholars represents a ‘new’ femininity (Gill, 2007), in which ‘hyper-sexual’ forms of (hetero)sexual expression are now expected of young women and girls, despite ostensibly being about choice and personal empowerment. In this article, I explore the constructions of girlhood and femininity amongst young women attending an elite, single-sex, private school in Melbourne, Australia. Elite schooling for girls is often associated with highly classed notions of (hetero)sexual modesty and propriety, epitomised in the reality television program Ladette to Lady. Here I consider how hyper-sexualities are configured within students’ constructions of themselves and others, and I explore their relationship to classed expectations of identity for privileged girls. I examine the role that classed norms of identity play in mediating these girls’ negotiations of hyper-sexualities.

National Cultural Policy submission

This was my submission to the Australian Federal Government’s call for submissions in response to the National Cultural Policy Discussion Paper.

Australian content and convergence

This article is a response to Kim Dalton's 2011 Henry Mayer Lecture. It focuses on Dalton's discussion of Australian content in the context of the government's ongoing Convergence Review.