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Modern, intensified aquaculture typically involves three production phases; hatchery, nursery, and grow-out. For redclaw crayfish aquaculture however, such delineation has been ill-defined. Farming of redclaw was initiated based on the putative beneficial physical and biological attributes of the species, which suggested production methods would be relatively simple. The simple approach proved to be inefficient and only partially effective, which hindered industry development. Hatchery technology now exists to supply seed stock for grow-out, but hatchery production is variable, and the performance of hatchery reared juveniles is inconsistent. A nursery phase has been proposed between hatchery production and grow-out of approximately 3 weeks duration, sufficient to allow 2 or more moults. An important primary parameter in the proposed nursery phase is the thermal regime that will support optimum survival and growth. This study quantified the effect of temperature on the growth and survival of redclaw juveniles for a 22-day nursery phase. Temperature had a statistically significant effect on the survival of juveniles, whereby, the high temperatures were associated with high mortality, and the lower temperature treatments were associated with very low mortality. Survival was 98 to 100% for craylings held at temperatures between 18°C and 22°C, and between 0% and 6% for craylings at temperature treatments of 25°C to 32°C. Mortalities within treatments between 25°C and 30°C, primarily occurred from day six to day eleven, corresponding with the initiation of moulting. Change of mass of crayfish was significantly higher with increasing temperature between 18°C and 22°C and at individual weights that suggest they had completed a moult. This study suggests a water temperature of 22°C is optimal for survival and growth in a nursery phase.

Cherax quadricarinatus (redclaw) aquaculture has not achieved the industry growth that had been predicted in the early days of development. Provision of quality juvenile crayfish seed stock has been identified as a critical factor in overcoming industry development inertia. Hatchery technology has been developed to produce independent craylings and a nursery phase is now being developed to nurture the delicate craylings to a more advanced and robust juvenile stage, suitable for pond stocking. As part of the nursery development, clear definitions of the successive stages from egg through the first several instars, are required. Although some morphological descriptions of the early stages of redclaw have been made, the characteristics and nomenclature for stages from egg through to an advanced juvenile need clarification. A naming system is proposed (Egg, L1, L2, J1, J2 and J3) for the first six instars from egg, based on gross morphology and allometric relationships. Egg volume, wet weight and ocular carapace length (OCL) were analysed through linear regression. Based on these variables, the size of each instar is defined. Descriptions and photographs of the six instars provide a visual reference for identification. Five of the six instars had a significant relationship between wet weight and OCL. Both significantly increased for each successive instar. Lyophilized (dry) weight was not significantly different between stages until after instar J1, where endogenous feeding begins. The growth of the first four instars, in terms of wet weight and OCL but not dry weight, suggests an extra endogenous source of nutrition in addition to the yolk supply. Branchial water uptake during ecdysis has been proposed as a route for dissolved organic matter or small particulate matter to be acquired by the crayfish during the lecithotrophic, nonexogenous feeding stages, as an additional food source that might further enhance growth and survival.

Redclaw, Cherax quadricariatus (von Martens) has shown promise as an aquaculture species but commercial development has been constrained by variability of production, perhaps due to poor survival and growth of early craylings. Diet contributes to survival and growth and previous studies have determined requirements for larger redclaw, but little research exists for the early craylings. An experiment was performed to evaluate survival and growth of early instar redclaw using four diets; Frippak (commercial shrimp diet), CSIRO compound diet, bloodworms, and on-grown Artemia. Bloodworms and Artemia produced significantly higher survival of craylings over two weeks than the two other diets. Artemia diet had a significantly higher weight increase than bloodworms or the CSIRO diet, but not Frippak, which did not differ from bloodworms or CSIRO. Biomass was significantly higher when fed Artemia. High mortality in the Frippak and CSIRO diet treatments were not wholly attributable to nutritional deficiencies as the manufactured diets became less physically accessible, potentially reducing intake, leading to difficulties completing ecdysis and eventually death. This study concluded that Artemia and bloodworms promoted highest survival, and Artemia and Frippak the highest weight gain. The best combination of survival, weight gain and biomass was with the Artemia diet.

The Australian Redclaw crayfish, Cherax quadricarinatus, has been the subject of aquaculture development for more than 3 decades. Farm production from Australia and from around the world for this species has been relatively low, as suitable production technology continues to develop. The production of redclaw juveniles for the purpose of stocking to ponds for on-growing to marketable size, has been a particular constraint and new approaches to breeding and mass production of craylings have provided renewed impetus to industry expansion. This paper reviews the literature concerning redclaw juvenile production and provides a status report of current practices and innovations that may support further expansion of redclaw aquaculture.

Aquaculture production of redclaw Cherax quadricarinatus (von Martens) in Australia, has never reached the high level projections made in the 1990’s (Jones and Ruscoe 1996). This can be attributed to a range of factors, but the most significant is the supply of seedstock. Although redclaw is advantaged by its uncomplicated reproductive biology with no free-living larval stages, reliance on natural reproduction to generate juveniles for growout purposes is inefficient. An alternative approach involves the artificial incubation of fertilized eggs to improve both quality and quantity of juveniles produced. Suitable technology for such incubation was developed in Europe to support the on-going efforts to produce crayfish plague free juveniles for restocking to natural water bodies. This technology has now been adapted to suit redclaw and for the purpose of mass production of seed crayfish for aquaculture. This paper details the development of the AquaVerde hatchery system, and the challenges to see it develop into fully commercial production, that could support expansion of the redclaw farming industry, both in Australia and elsewhere in the world.

One of the main challenges for spiny lobster aquaculture is the successful development of formulated feeds that are attractive, readily consumed by lobsters and promote optimal growth and survival. In a 54-day growth trial, we investigated the performance of four moist formulated feeds containing A) non-homogenised flesh ingredients; B) fish meal only; C) 10% krill meal; or D) homogenised flesh ingredients; and a reference diet of shucked blue mussel (Mytilus galloprovincialis) flesh, on growth, nutritional condition and feeding behaviour of juvenile tropical spiny lobster (Panulirus ornatus) reared either communally or individually. Growth and survival achieved by lobsters fed mussel were significantly higher than all other treatments. However, lobsters fed the formulated feed containing 10% krill meal (treatment C) and reared communally had a significantly higher growth, survival and feeding performance when compared to the formulated feeds with inclusion of non-homogenised and homogenised flesh ingredients (treatments A and D). The highest levels of feed interaction and pellet consumption among the formulated feeds were also recorded for treatment C. We demonstrated that the inclusion of krill meal in formulated feeds provides a benefit when compared to the inclusion of the flesh ingredients. Flesh ingredient format (homogenised or non-homogenised) had no effect on growth performance of lobsters, suggesting that the process of homogenisation of flesh ingredients does not provide any benefit in promoting feed consumption. Furthermore, time-series photography analysis trials showed that all the formulated feeds only promoted a feeding response within the first 2–3 h post-feeding, whereas mussel retained its attractiveness throughout the feeding period. These results suggest that the prolonged attractiveness remains an impediment for formulated feed performance in lobster culture. The present study also showed that growth performance and feeding response were higher in lobsters reared communally than individually. As observed in other spiny lobster species, it is likely that social interactions in communal housing may have provided cues that stimulated feeding responses and promoted higher growth rates.

On-growing of wild caught rock lobster pueruli first began in Indonesia around 2004 as a derivative of seaweed and fish culture. In the southeast of the Indonesian island of Lombok, farmers growing seaweed or grouper noticed pueruli settling on their apparatus. Realizing these were small lobsters, they stocked them to cages to on-grow, and thus the Indonesian lobster farming industry began. Despite relatively high abundance of the naturally-settling lobster seed, no more than 50 tonnes of lobster were produced each year to 2009 due to limited farming skills and nutritionally deficient feed. The primary species was Panulirus homarus (Linnaeus, 1758), and it was typically on-grown for around 12 mo to a mean size of around 100 g, fetching a price of around 35,000 Indonesian Rupiah per kg, less than $US30. At that time, Vietnam was experiencing rapid growth of its own lobster farming industry, which was producing >1,500 tonnes of 1 kg lobsters of the species Panulirus ornatus (Fabricius, 1798), with price exceeding $US60 per kg. Collaborative research involving Vietnam and Australian research agencies was assisting the Vietnam lobster farmers to achieve best farming practices, and that research was expanded to transfer the successful practices of Vietnam to Indonesia. In 2017, 13 yrs after the Indonesian lobster farming began, growout production has declined by >95% due to perceptions of risk by farmers, and through a policy intervention. Here, I describe the progress and constraints of Indonesian lobster aquaculture, and the opportunity and mechanisms available to reach its potential.

The literature on late-stage larval and puerulus settlement of tropical spiny lobsters suggests that a broad range of visually-assessed variables may play a role in the selection of settlement substrates. These variables include light level, luminosity, degree of exposure, and the availability of edges, crevices and clefts. A fishery has developed in Indonesia, that captures pueruli for grow-out purposes, along the entire southern coastline from Java to Sumbawa. The present study builds on knowledge gained on the behaviour and substrate preferences of settling pueruli by examining aspects of collector design and substrate surface characteristics in regard to catch rates. A series of tank-based experiments were used to examine preferences for various attributes of collector materials, and preferred material characteristics were then tested in a field experiment to verify the laboratory results. In the tank experiment the most preferred substrate was cement bag paper, followed by insect mesh, weed netting, PVC rubber and cement bag plastic. Crevice angles of 10° and 20° were significantly preferred over 30°. The substrate level and other substrates had less influence on settlement. However, both the lunar phase and type of materials tested in the field had a significant effect on settlement. Significantly greater numbers of pueruli were caught at the time of the new moon than at other moon phases. Cement bag paper was the most preferred material in the field, followed by cement bag plastic, insect mesh, weed fabric, and PVC rubber.

Aquaculture has a critical role in achieving the UN&rsquo, s Sustainable Development Goals of increasing benefits that low-income and least-developed countries derive from marine resources. Its capacity to deliver these outcomes is challenging, particularly for marginalized groups. This is especially true if the introduction of novel technologies is applied with incomplete understanding of socio-economic and bio-physical contexts. We examined what socio-economic factors affect people&rsquo, s perceptions of adoption of lobster aquaculture in rural households in Indonesia. We used multiple linear regression with model averaging to test the influence of five capital assets (human, social, natural, physical, and financial), including agency, equity, and household sensitivity, on people&rsquo, s perceived ability to adopt lobster aquaculture. Agency and sensitivity had the greatest influence on the dependent variable. We then used correlation analysis to develop a heuristic model of potential indirect causal mechanisms affecting people&rsquo, s perceptions of adoption. Our results point to the existence of a &lsquo, sensitivity trap&rsquo, where more sensitive or marginalized households are less likely to engage in new economic opportunities. We emphasize the value of multifaceted programs for improving livelihoods, particularly for poorer, more vulnerable households as one way to support the UN&rsquo, s commitment to using aquaculture as a pathway to achieving sustainable development.

Indonesia has a unique opportunity to establish the world's largest lobster aquaculture industry, based on a significant natural resource of settling puerulus. These seed lobsters can be captured and on-grown to generate high value, consumption size lobsters. However, existing fisheries regulation prohibits fishing of these seed lobsters in Indonesia. Nevertheless, seed fishing occurs widely, and the seed are smuggled into Vietnam, where the Vietnamese gain most of the commercial benefit. By removing access to pueruli and grow-out opportunities, these regulations have diminished the capacity of Indonesian lobster farmers to develop a sustainable grow-out industry. Although the new policies were introduced as a management intervention to protect adult lobster stocks, they have had the unintended consequence of preventing development of lobster aquaculture while having no known benefit on abundance of adult lobsters. This study collected data on the puerulus available in Indonesia, species composition, seasonality, and capture methods. A census of seed capture determined that 5,243,887 pueruli were fished from two bays in the southeast of Lombok in 2014, representing 64,787 pueruli per km2. Surveys beyond Lombok determined there was high abundance of seed in areas with similar environmental characteristics, where local communities had also engaged in seed fishing. The locations identified as having substantial puerulus abundance comprised the southern coast of Java, Bali, Lombok and Sumbawa covering a distance of 1500 km. Puerulus abundance is highest in enclosed bays with distinct currents, relatively high turbidity attributable to terrestrial inflows, and muddy/sandy substrates. Satellite imaging identified all such suitable locations for puerulus settlement, enabling an estimate of total puerulus catch of 103,480,283 per year. The composition of puerulus fished consisted of two species, Panulirus homarus and P. ornatus. P. homarus was most abundant representing between 63 and 87%, while P. ornatus represented 37 to 13%. Seasonality of catch was unclear, with low catch between December and March and higher catches from April to November. The magnitude of the estimated puerulus resource of Indonesia is >20 times greater than that of Vietnam. If used for aquaculture, the seed available can support an industry generating >12,500 t of market size lobster, and provide social and economic benefit to many thousands of households. To achieve this, fisheries policies could be revised and a regulatory framework established to manage the puerulus fishery and support lobster farming. Tropical marine rock lobster aquaculture is a major opportunity for high-value aquaculture production for the Indonesian economy.

Development of spiny (rock) lobster aquaculture is of special interest because market demand continues to increase while capture fisheries production remains static and with little likelihood of any increase. This chapter provides a synopsis of information about the history, development, status and future of tropical spiny lobster aquaculture with a particular focus on Vietnam and Indonesia, where considerable development has already occurred. Vietnam is the only country in the world where farming of lobsters is fully developed and commercially successful. The Vietnamese industry is based on a natural supply of seed lobsters – the puerulus stage, as hatchery supply is not yet available due to the difficult technical demands of rearing spiny lobster larvae in captivity. Vietnam currently produces around 1600 tonnes of premium grade lobsters, primarily of the species Panulirus ornatus, that are exported to China where the price is higher. The industry is valued at over $US120 million. This success led to significant interest in Indonesia where a fishery for seed lobsters has become well developed, with a catch 10–20 times greater than that of Vietnam. However, growout of lobster in Indonesia remains insignificant due to adverse government policy and lack of farmer knowledge and skills. The seed lobsters available in Indonesia are primarily Panulirus homarus, a species with excellent production characteristics like P. ornatus, although with lesser value. Extraordinarily high abundance of naturally settling seed lobsters is apparent in selected areas due to a confluence of suitable conditions that create a high concentration of late-stage larvae near the coast. These areas have been termed hotspots, as the availability of settling seed is much higher than other areas. Such hotspots are now recognised in the central northern coast of Vietnam – supplying their growout industry – and the central southern coast of Indonesia. Natural mortality of the seed lobsters in these areas is correspondingly high due to insufficient settlement habitat and fish predation. Consequently, responsible fishing of these seed is sustainable, providing a valuable resource that can be on-grown for benefit of impoverished coastal communities. Innovative and inexpensive techniques have been developed to effectively catch the seed as they swim towards the coast seeking suitable habitat. In Vietnam, the seed are typically sold by fishers to dealers, who aggregate supplies and then on-sell to nursery farmers. Nursing consists of rearing the seed lobsters in small suspended or submerged cages, with a diet of fresh seafood – crabs, mollusc and fish. Advanced juvenile lobsters are produced that are in turn on-sold to growout farmers who stock them to larger floating cages, suspended from simple floating frames.

Counsellors and psychologists worldwide use different theoretical approaches at least sometimes in conjunction. The theoretical orientation of Australian practising psychologists and psychotherapists appears to be following an international trend that emphasises eclectic or integrative use of the orientations. The aim of the current study of 24 experienced counsellors and psychotherapists in Australia was to identify dominant theoretical orientations used in assisting clients and to compare these orientations with the trend towards integration of theories in practice. We were also interested in which of the major theories were most used in practice by these professionals and what strategies or skills they considered most important. Twenty-four counsellors and psychotherapists thus responded to a series of online survey questions about their personal approaches, resources and practices. Cognitive-Behavioural Therapy (CBT) was the most common of all therapies cited, but person-centred approaches were also popular. However, 21 of the 24 psychotherapists adopted an eclectic or integrative approach (using three or more approaches in their practice). This current finding is consistent with some earlier Australian research, though the eclectic trend may be strengthening. This study also provides insight into the key strategies that the 24 psychotherapists indicate as making a difference for clients, and outlines main reasons why they joined the profession.

Spiny lobster farming is a feasible strategy to address increasing export demand currently not met by the capture fishery. However, farming currently relies on natural lobster seed availability, which in turn is limited by the fishers' lack of skill in catching and handling pueruli as well as applying suitable grow-out practises. In Indonesia, particularly on Lombok, a viable puerulus fishery has been established supporting a local grow-out industry. Anecdotal evidence suggests water depth may be an important factor for the effectiveness of collecting equipment. This paper reports on an experiment that examined the effect of depth and trap type on the effectiveness of puerulus collectors at the end of the wet season, when pueruli abundance is greatest. Four trap types were deployed at 5 depths: i) 1 m below surface; ii) 2 m below surface; iii) middle of the water column; iv) 1 m above the sea floor; and v) touching the sea floor, with 6 replicates of each. The data were analysed to identify the effect of depth and trap type using a two-way ANOVA. Significant differences for depth and trap type were found for the primary species caught, Panulirus homarus and Panulirus ornatus . The greatest catch of P. homarus was on the sea floor using a cement paper trap. For P. ornatus catch rate was less strongly correlated with a specific depth or trap type, although catch was highest at or near the sea floor in cement paper traps.

Dietary supplementation with mannan oligosaccharide (MOS) has been demonstrated to provide significant benefits to growth and health of many species of fish and crustaceans. An investigation was made to assess the effect of MOS supplementation on the diet of the tropical lobster Panulirus homarus. The aim of the study was to test the effect of various dietary inclusion levels of MOS on growth, survival rate, intestinal morphology and bacterial abundance, haemocyte make-up, and tissue composition of P. homarus lobsters. A manufactured, semi-moist diet was used as a basal diet and supplemented with 0.2%, 0.4%, 0.6% and 0.8% MOS inclusion, and fed to lobsters with an initial mean weight of 0.16 g for 56 days. A typical fishery bycatch mixture was used as a reference control diet. Growth rate of lobsters was significantly higher for those fed diets supplemented with 0.4 and 0.6% MOS than those fed an un-supplemented diet or bycatch. Survival rates of lobsters ranged from 68 to 78%. The survival rate was significantly higher in lobsters fed diets with 0.2% and 0.4% MOS supplementation and bycatch, compared with those fed the basal or 0.6% MOS diet. There was no significant difference in differential haemocyte count of lobsters fed with various MOS levels or bycatch. The mid-gut surface area of lobsters fed diets supplemented with 0.2%, 0.4% and 0.6% MOS was significantly higher than that of lobsters fed on control, 0.8% MOS or bycatch. The total Vibrio count in the mid-gut of lobsters fed any MOS diet was significantly lower than that of lobsters fed either the control or the bycatch diet. There was no significant difference in protein, lipid or ash content in lobsters fed the different diets. There were significant correlations between concentrations of MOS in diets and lobster growth rates. Optimal MOS concentration was estimated to be 0.69% at day 14 (R2 = 76.79%), 0.55% at day 28 (R2 = 88.18%), 0.48% at day 42 (R2 = 97.72%) and 0.47% at day 56 (R2 = 94.42%), demonstrating a decreasing requirement for MOS with increasing lobster size. In conclusion, mannan oligosaccharide supplementation appears to be effective for improving growth, survival and gastro-intestinal health of the lobster, P. homarus.

The period over which spiny lobster eggs develop varies widely and is related to incubation temperature. For the tropical rock lobster (Panulirus ornatus), this relationship is found to be: Incubation period (days)=95.444–2.482×Temperature (°C) for incubation temperatures between 24 and 30 °C. Incubation temperatures ≥32 °C are unsuitable for this species and result in the termination of egg clutches. Additionally, egg clutches incubated at lower temperatures hatched over more nights than those at higher temperatures. These findings mean that lead times to larval hatch can now be predicted for this species, allowing for preparation time prior to larval culture.

Interest in the development of aquaculture of the tropical spiny lobster, Panulirus ornatus, has increased markedly over the past 10 yr because of strong market demand and high prices. In Australia, economic conditions will necessitate that a semi-intensive approach be taken, possibly involving managed environmental conditions. Identification of optimal temperature and salinity levels will be necessary, and therefore two experiments were performed to examine these two parameters. Juvenile lobsters were grown in tanks at five temperatures (19, 22, 25, 28 and 31 C). Growth was significantly affected by temperature (P < 0.01), and maximal growth occurred at 25-31 C. Examination of the temperature effect on molt increment and intermolt period indicated that 27 C was the optimal temperature, at which molt increment was greatest and intermolt period the least. Temperature also had a significant (P < 0.01) positive effect on apparent feed intake (AFI). Juvenile lobsters were also exposed to four different salinities (20, 25, 30 and 35 ppt) over a period of 91 d. Significant differences (P < 0.01) were apparent for both survival and growth. Lowest survival occurred at 35 ppt which may be attributable to higher cannibalism at that salinity. Growth was highest at 35 ppt and progressively less at lower salinities. Although full marine salinity (35 ppt) will generate best performance of P. ornatus, its capacity to tolerate reduced salinity will provide greater opportunity to develop commercial aquaculture.

It is proposed that an athlete's overtrained state is more perceptible in its etiology, diagnosis, treatment and prevention if considered from the context of a biopsychosocial disorder of adjustment. By shifting focus from a limited notion of excessive training loads and inadequate recovery schedules onto a comprehensive model of maladjustment, the full scope of the phenomenon becomes clearer. Specifically, the overtrained state is reconceptualized as an Adjustment Disorder and thus should be treated from the perspective of this diagnosis. Adjustment Disorder is viewed as a response to an identifiable stressor or stressors that results in clinically significant symptoms, and ‘can be triggered by a stressor of any severity and may involve a wide range of possible symptoms’ (DSM-IV-TR, 2000, p. 682). A rationale for the adoption of this definition is proposed. Included in this rationale is a comprehensive model of maladjustment with an overview of relevant subtypes to clarify the complex interaction of vari...

This article raises a specific concern that is highlighted by the recent decision to raise the minimum standard for registration as a psychologist in Australia to postgraduate masters degree level. It is suggested that such an objective is limited because it does not address other, more important variables required to ensure that minimum standards for registration as a psychologist are achieved. Specifically, it is proposed that unless the existing methodology and content of both undergraduate and fourth year graduate university training for psychologists is improved to incorporate vital areas of practice, standards will continue to remain low regardless of the introduction of compulsory fifth and sixth years of postgraduate education. This article provides an overview of the issue while suggesting an alternative approach for developing professional expertise in those wishing to embark on a career in psychology.

We have evaluated the potential of a formulated diet as a replacement for live and fresh feeds for 7-day post-hatch Panulirus ornatus phyllosomata and also investigated the effect of conditioning phyllosomata for 14–21 days on live feeds prior to weaning onto a 100% formulated diet. In the first trial, the highest survival (>55%) was consistently shown by phyllosomata fed a diet consisting of a 50% combination of Artemia nauplii and 50% Greenshell mussel, followed by phyllosomata fed 50% Artemia nauplii and 50% formulated diet and, thirdly, by those receiving 100% Artemia nauplii. The second trial assessed the replacement of on-grown Artemia with proportions of formulated diet and Greenshell mussel that differed from those used in trial 1. Phyllosomata fed a 75% combination of formulated diet and 25% on-grown Artemia and 50% on-grown Artemia and 50% Greenshell mussel consistently showed the highest survival (>75%). Combinations of Greenshell mussel and formulated diet resulted in significantly (P 35%) among all treatments, while those fed a 50%-squid CP diet showed a significant (P < 0.05) increase in mortality at day 24. The results of these trials demonstrate that hatcheries can potentially replace 75% of live on-grown Artemia with a formulated diet 7 days after hatch. The poor performance associated with feeding combinations of Greenshell mussel and formulated diet, and 100% formulated diet as well as conditioning phyllosomata for 14–21 days on live feeds prior to weaning onto a formulated diet highlights the importance of providing Artemia to stimulate feeding.

Spanier, Ehud ... et. al.-- Contribution to the Supplement: Lobsters in a Changing Climate.-- 15 pages, 7 figures, Lobsters are important resources throughout the world's oceans, providing food security, employment, and a trading commodity. Whereas marine biologists generally focus on modern impacts of fisheries, here we explore the deep history of lobster exploitation by prehistorical humans and ancient civilizations, through the first half of the 20th century. Evidence of lobster use comprises midden remains, artwork, artefacts, writings about lobsters, and written sources describing the fishing practices of indigenous peoples. Evidence from archaeological dig sites is potentially biased because lobster shells are relatively thin and easily degraded in most midden soils; in some cases, they may have been used as fertilizer for crops instead of being dumped in middens. Lobsters were a valuable food and economic resource for early coastal peoples, and ancient Greek and Roman Mediterranean civilizations amassed considerable knowledge of their biology and fisheries. Before European contact, lobsters were utilized by indigenous societies in the Americas, southern Africa, Australia, and New Zealand at seemingly sustainable levels, even while other fish and molluscan species may have been overfished. All written records suggest that coastal lobster populations were dense, even in the presence of abundant and large groundfish predators, and that lobsters were much larger than at present. Lobsters gained a reputation as “food for the poor” in 17th and 18th century Europe and parts of North America, but became a fashionable seafood commodity during the mid-19th century. High demand led to intensified fishing effort with improved fishing gear and boats, and advances in preservation and long-distance transport. By the early 20th century, coastal stocks were overfished in many places and average lobster size was significantly reduced. With overfishing came attempts to regulate fisheries, which have varied over time and have met with limited success

Two experiments were performed to assess the effect of photoperiod and temperature on spawning of Panulirus ornatus. In experiment 1, sexually mature lobsters taken from the wild during summer were held at one of two photoperiods, winter (13 Light:11 Dark) and summer (14.5 Light:9.5 Dark). Additionally, lobsters were also exposed to either summer (29°C) or winter (24°C) average water temperatures. Spawning was significantly greater when animals were exposed to summer photoperiod than to winter photoperiod, irrespective of temperature. Although a higher percentage of lobsters spawned when placed under a higher temperature, this trend was not statistically significant. In experiment 2, sexually mature lobsters were taken from the wild during winter and exposed to the same two photoperiods as in experiment 1, at a summer equivalent temperature of 29°C. Breeding started earlier and was more successful at the summer photoperiod. Time to first breeding was 17 weeks after exposure to summer photoperiod, compared with less than 1 week in experiment 1, and did not occur until individuals had moulted. Moulting occurred in 81% of lobsters, primarily after an increase in temperature to 29°C. The time between moulting and mating was varied and there was no significant difference in moult frequency between the two experimental photoperiods. After the lobsters had moulted, breeding success was reached earlier if photoperiod was lengthened. Results suggest photoperiod is the primary cue for the onset of gonad maturity and mating activity, with temperature playing a less important role. Physiological rest and possibly a moult may be required between breeding seasons before spawning can occur. Furthermore, temperature may be an important cue for pre-reproduction moulting.

Two experiments were conducted to assess the water stability of a practical research diet manufactured with various binders and differing levels of moisture. In the first experiment the binders – agar, gelatine, carrageenan, and carboxymethylcellulose (CMC) were included at both 3 and 5% of total ingredient weight. All binders were tested with equal ingredient weight to water volume, and additionally carrageenan was tested in a diet with double the water volume. The dry matter remaining following immersion for up to 180 min was calculated and the rate of pellet decay was modelled using the Weibull distribution. The analysis revealed that the rate of dry matter loss decreased with time, and that carrageenan and CMC binders were significantly better (P

Two lines of redclaw crayfish (Cherax quadricarinatus) were maintained for four generations. One line was selected for increased harvest weight at 9 months, and the other maintained as an unselected control. To increase the heritability and limit inbreeding, lines were subdivided into cohorts with selection based on weight differences from cohort means. Selection increased harvest weight. In generation 4, weights averaged 61.6 g for the selected line and 49.3 g for the control line (s.e. diff. 2.3). The percentage of females carrying eggs at harvest was 9.8 in the selected line and 18.1 in the control line (s.e. diff. 4.0) suggesting that selection may have diverted energy from breeding activity to growth by delaying sexual maturity. Selection increased the carapace and tail length of females relative to their body weight. Estimates of realised heritabilities for harvest weight varied from 0.38±0.06 in year 1 to 0.13±0.02 in year 4. A practical selection program for redclaw could include periods of closed line selection alternating with test crossing with outside stocks to replenish genetic variation.

Here we utilize a combination of genetic data, oceanographic data, and local ecological knowledge to assess connectivity patterns of the ornate spiny lobster Panulirus ornatus (Fabricius, 1798) in the South-East Asian archipelago from Vietnam to Australia. Partial mitochondrial DNA control region and 10 polymorphic microsatellites did not detect genetic structure of 216 wild P. ornatus samples from Australia, Indonesia and Vietnam. Analyses show no evidence for genetic differentiation among populations (mtDNA control region sequences ΦST = -0.008; microsatellite loci FST = 0.003). A lack of evidence for regional or localized mtDNA haplotype clusters, or geographic clusters of microsatellite genotypes, reveals a pattern of high gene flow in P. ornatus throughout the South-East Asian Archipelago. This lack of genetic structure may be due to the oceanography-driven connectivity of the pelagic lobster larvae between spawning grounds in Papua New Guinea, the Philippines and, possibly, Indonesia. The connectivity cycle necessitates three generations. The lack of genetic structure of P. ornatus population in the South-East Asian archipelago has important implications for the sustainable management of this lobster in that the species within the region needs to be managed as one genetic stock.

An experiment was designed to assess the relative performance of several shelter types on the production of redclaw crayfish Cherar quadricarinatus under earthen pond conditions. Juvenile crayfish with a mean stocking weight of 12.76 g were cultured in 24 net pens at 12.5 m2 within a 0.2 ha earthen pond, and were provided with one of five shelter types or no shelter over 162 d. The various shelter types assessed were: mesh bundles, pipe stacks, car tires, elevated cement/fiber-board sheets, and cement/fiber-board sheets laid flat on the substrate. Crayfish in each pen were fed a formulated pellet diet three times each week. Treatments were assessed on the basis of crayfish growth, survival, harvest biomass and berry rate among females at harvest. There was no significant effect (P > 0.05) of shelter type on growth; however, there was a highly significant effect (P < 0.001) on survival with mesh bundles (75.1%), tires (51.4%), and pipe stacks (43.25%) performing significantly better than the no shelter control (15%). The consequence of equal growth and differing survival among treatments produced significant differences in harvest biomass (P < 0.01). There were also significant differences in berry rate for the different treatments (P= 0.002), and a significant negative correlation of berry rate on survival for those treatments where shelter was provided. This experiment showed that the shelter types provided during pond culture had a significant effect on harvested biomass, primarily through its effect on survival. The efficacy of the mesh bundle shelters may be attributable to the variability in the size of the spaces provided, and the ability of the mesh to separate many individuals relative to the overall volume of the shelter.

This paper provides a review and summary of strain comparison and selective breeding work carried out on redclaw crayfish Cherax quadricarinatus (von Martens) at the Queensland Department of Primary Industries, Freshwater Fisheries and Aquaculture Centre, Walkamin. Redclaw crayfish are a highly marketable, environmentally tolerant, freshwater crayfish with a moderately fast, but variable, growth rate. Five strains of the species were assessed morphologically and in terms of age at maturity. A non-replicated production trial was also carried out before two strains, from the Gilbert and Flinders rivers in North Queensland, were chosen to be part of an experimental selective breeding programme for improved growth. Initially, 14 families of each strain were randomly mated and grown out. At this point, a size-related selection took place, with the largest animals from each family forming a selected line, and individuals from around the mean forming a control line. Within-family selection and reciprocal mating between families was performed. Data were collected after each of two generations of growout and analysed by analysis of variance. Significant differences (P< 0.05) were measured between strains, sexes and between selected and control lines. Selected individuals grew 9.5% faster than the controls. Recommendations for selective breeding research involving freshwater crayfish are presented.

Commercial-scale production of juvenile redclaw crayfish was conducted in earthen ponds. Based upon the results of previous experimental studies in tanks and aquaria, earthen ponds (1300 and 2600 m2) were furnished with juvenile crayfish shelters, and were prepared and managed to maximise availability of zooplankton. Juvenile redclaw were introduced by stocking ponds with egg-bearing females. Stocking density, as expressed by number of fertile eggs introduced, ranged from 74 to 326/ m2. Ponds were harvested after culture periods ranging from 45 to 62 days. Juvenile number at harvest ranged from around 6000 to over 36 000, representing a mean of 63.2 juveniles per maternal survivor. Mean size at harvest ranged from 0.31 to 1.00 g, representing growth of 9.7 to 36.9 mg/day. Results suggest that managed pond production of juvenile redclaw is commercially viable at the production rates achieved, and that a considerable increase in productivity is possible with increased availability of shelter and improved zooplankton management techniques.

Newly hatched redclaw crayfish Cherax quadricarinatus were reared for 39 days in aquaria using various combinations of food and habitat. Food treatments were fresh zooplankton and a high protein formulated flake diet. Habitat treatments involved the presence/absence of a floating aquatic macrophyte, Pistia stratiodes. Both survival and growth of juveniles were significantly influenced by the type of food and habitat. Fresh zooplankton produced the best growth. An interactive effect between food type and Pistia resulted in differential survival. Use of aquatic macrophytes for habitat in intensive juvenile production systems is not recommended.

Procedures were developed for the controlled production of juvenile redclaw crayfish, Cherax quadricarinatus in tanks over two seasons. These included broodstock handling methods and involved the definition of an in vivo ovary staging technique which permitted recognition of immature, maturing and mature females. Hatchery techniques were also defined which demonstrated that male:female ratios of up to 1:4 were equivalent for successful mating and spawning. Up to 97% of females spawned and carried eggs through to hatching when held in tanks at between 24.5 and 27.6 °C mean daily temperature and exposed to 14:10 hours light:dark day length. A sequential series of seven egg stages was defined from egg release through to hatching, based on morphological characteristics. The mean duration of each stage was measured and cumulative statistics calculated, indicating a mean incubatory period of 72.1 days (range 47 to 84) and 66.3 days (56 to 71), respectively, for the two hatchery runs. An exponential function was calculated which defines the relationship of fecundity and female size and which indicates that fecundity ranges from approximately 200 to 1000 eggs per female. Nursery procedures were developed which indicate difficulties with using the floating water plant Pistia as juvenile habitat, and the benefits of using artificial shelters. Newly hatched juveniles stocked at between 980 and 1842 m 2 , and fed a combination of formulated flake food and fresh zooplankton, survived well (mean 52%) and increased in size by between 500 and 900% over 28 to 50 days. The research demonstrates that C. quadricarinatus can be easily bred in captivity and juveniles reared successfully with relatively simple facilities and techniques.

Manual sexing of redclaw crayfish Cherar quadricurinatus was undertaken to evaluate the feasibility of monosex culture and to establish growth and yield characteristics of single sex populations. Although the all-male population exhibited greater mean weight after 10 mo of growout, all-female and mixed sex populations achieved greater total yields due to significant juvenile recruitment. Commercial cultivation of all-male populations would be advantageous as in-pond reproduction is greatly abated, growth is superior and marketable yield is higher. Apparent sexual lability of juveniles combined with the laborious nature of manual sexing may render manual sexing unsuitable for commercial applications.

[Extract] Bay lobsters of the genus Thenus are a valuable component of the incidental catch of the penaeid trawl fisheries of northern Australia. The 2 species present, Thenus indicus Leach, 1815 and Thenus orientalis (Lund, 1793), have mutually exclusive distributions. For each species, relative abundance, size and sex composition were measured monthly and related to physical characteristics including temperature, salinity, depth and sediment type. Both species populations were characterised by contagious distributions. Mean density of T. indicus was 1.78 (±0.15) lobsters ha⁻¹, while that of T. orientalis was 2.02(±0.13). In both populations, depth and sediment type were significantly correlated with abundance. T. indicus was most abundant in depths of 10-30 m and where sediments were characterised by a preponderance of find sands and silt. In contrast, T. orientalis was most abundant in 1.00 mm particle size. In both species, mean size varied significantly thorughout the year as a function of growth and recruitment. Male and female T. indicus were equally abundant, while male T. orientalis were significantly more abundant than females.

Chemical communication has received very little attention in the field of crustacean aquaculture research. It has been investigated mainly with regard to the extent that chemical cues might be involved in social control of growth, which results in growth suppression and size variation among individuals under culture conditions, but no consistent conclusion has emerged that stimulated further development and application of solutions based on this knowledge. Implementation of knowledge on chemical communication in crustacean aquaculture has not gone further than some preliminary trials of the incorporation of pheromones as feeding attractants or of their use to facilitate trapping. In this review we attempted to identify those aquaculture procedures in which knowledge of chemical communication might be implemented, to indicate possible uses and to suggest possible solutions related to various aquacultured crustaceans. In most cases solutions based on chemical communication could probably be integrated into current culture techniques and would serve to enhance their efficiency. To achieve this aim, pheromones and potent chemical components that mediate behavioral and physiological processes relevant to aquaculture should be identified and synthetic versions and technical means for their efficient application should be developed.

Commercial aquaculture of marine lobsters is an attractive proposition, as most species are high value with established market demand, and fishery production is static or diminishing. Nevertheless, achievement of commercial success will necessitate resolution of technical difficulties associated with on-growing of aggressive species (clawed lobsters) or with rearing the larvae, which for spiny and slipper lobsters is generally a painstaking and protracted process. Notwithstanding these technical challenges, increasing market demand for the product is driving a substantial research and development effort around the world to develop commercial lobster farming technology. This chapter reports on the status of that effort, the successes and obstacles.

L'examen morphologique de Scyllaridae du genre Thenus Leach a indique une difference significative avec les autres genres. Le trait le plus frappant est la compression dorso-ventrale du corps. Les analyses morphometriques ont revele des discontinuites entre mâles et femelles et entre deux types morphologiques de T. orientalis (Lund, 1783). Ces differences correspondaient a la reconnaissance de deux especes distinctes: T. orientalis et Thenus sp. nov. La signification adaptive des caracteristiques morphologiques decrites est discutee.