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Plasticity in the reproductive biology of the smooth marron Cheraxcainii (Decapoda: Parastacidae): A large freshwater crayfish of south-western Australia

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... Cherax tenuimanus Smith (1912) is geographically restricted to the Margaret River, and is referred to as 'Margaret River hairy marron' to differentiate them from 'smooth marron' , Cherax cainii Austin, 2002 (Austin andRyan, 2002) with a wide range (Bunn et al., 2008). C. cainii have been translocated multiple times throughout the south-west of Australia and other areas in Australia for the purpose of aquaculture with production at around 60 tonnes per annum (Stanley, 2016) and recreational fishing (Morrissy, 1992;Beatty et al., 2016), because they breed successfully in captivity. One of these locations is the Margaret River, where C. cainii are displacing C. tenuimanus, possibly because the former has higher fecundity and starts reproduction earlier than the latter (Austin and Ryan, 2002;Bunn et al., 2008;Duffy et al., 2014). ...
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Captive breeding is a vital tool in the conservation of highly endangered species, as it is for the Margaret River hairy marron, Cherax tenuimanus , from the south west of Australia. A close relative, Cherax cainii , has almost completely displaced C. tenuimanus in the wild and is a successful aquaculture species, whereas C. tenuimanus has performed poorly in captivity. We used untargeted liquid chromatography-mass spectrometry to obtain metabolomic profiles of female and male C. tenuimanus held in controlled aquarium conditions during their reproductive period. Using repeated haemolymph sampling we tracked the metabolomic profiles of animals just prior to and for a period of up to 34 days after pairing with a similar sized potential mate. We identified 54 reproducible annotated metabolites including amino acids, fatty acids, biogenic amines, purine and pyrimidine metabolites and excretion metabolites. Hierarchical clustering analysis distinguished five metabolite clusters. Principal component-canonical variate analysis clearly distinguished females from males, both unpaired and paired; similar trends in profile changes in both sexes after pairing; and a striking shift in males upon pairing. We discuss three main patterns of metabolomic responses: differentiation between sexes; reactive responses to the disturbance of pairing; and convergent response to the disturbance of pairing for males. Females generally had higher concentrations of metabolites involved in metabolic rate, mobilisation of energy stores and stress. Responses to the disturbance of pairing were also related to elevated stress. Females were mobilising lipid stores to deposit yolk, whereas males had a rapid and strong response to pairing, with shifts in metabolites associated with gonad development and communication, indicating males could complete reproductive readiness only once paired with a female. The metabolomic profiles support a previously proposed potential mechanism for displacement of C. tenuimanus by C. cainii in the wild and identify several biomarkers for testing hypotheses regarding reproductive success using targeted metabolomics.
... The MRS consisted of five survey occasions, in the Austral winterspring, between 28 June and 9 September 2017 (inter-survey period 14 days). The trapping protocols followed those previously used in other biological studies conducted on the species (see Beatty, de Graaf, Duffy, Nguyen, & Molony, 2016;Beatty, de Graaf, Molony, Nguyen, & Pollock, 2011). The MRS targeted animals (>30 mm orbital carapace length, OCL) that could be caught using box-traps (600 mm length, 450 mm width, 200 mm height, 10 mm square mesh) baited with commercial C. cainii pelleted feed (Weston). ...
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Almost one third of all freshwater crayfishes are threatened with extinction. The factors influencing the distribution of freshwater crayfishes in lentic systems are poorly understood, hampering the conservation and enhancement of those populations. Cherax cainii is the third largest freshwater crayfish in the world and is endemic to south‐western Australia. The distribution of the species has declined markedly, largely attributable to secondary salinization and habitat decline. There is the potential for population enhancement through habitat restoration and the restocking of reservoirs that act as important non‐salinized refuges; however, there is limited understanding of the distribution and habitat associations of C. cainii in these systems. Mark–recapture was undertaken to determine the population abundance and fine‐scale distribution of C. cainii in a large reservoir over a 5‐month period, with generalized linear mixed modelling used to determine those factors that explained the variation in its distribution. Cherax cainii distribution in the reservoir was positively associated with complex habitat (large woody material) and the level of inaccessibility to humans, and negatively associated with depth. The population had a non‐uniform distribution within the reservoir with significant hot‐ and cold‐spots present and there was limited distance between recaptures during the coolest period of the year. The findings suggest that C. cainii would benefit from the provision of additional complex habitat in such habitat depauperate reservoirs to provide increased shelter from predators. It may also be vulnerable to localized depletion through legal and illegal fishing pressure. The study highlights the importance of understanding habitat preferences and movement patterns of freshwater crayfish to underpin their conservation.
... Variation in growth rates between individuals has been widely reported in freshwater crayfish. Beatty et al. (2016) reported plasticity in growth rates of Cherax cainii between lotic and lentic habitats, and Rebrina et al. (2015) discussed variability in growth and life history parameters in Pacifastacus leniusculus (Dana, 1852) as it invaded areas inhabited by Astacus leptodactylus Eschscholtz, 1823, in Croatia. There is particular interest in the existence of different personalities within animals in a single population, which trade off characteristics such as boldness against mortality risk. ...
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An on-going opportunistic tagging program marked almost 600 giant freshwater crayfish, Astacopsis gouldi, between 22-222 mm carapace length from 123 localities on 62 rivers in Tasmania since 1998. Eighty animals were recaptured once, 50 more than once, and the longest period between initial and latest capture was 8 years. These data were analysed to examine differences in size and growth between the sexes, between the disjunct eastern and western ranges of the species, and between catchments on nutrient-poor and nutrient-rich rocks. Male animals were heavier per unit length than females, as were animals from the western part of the range compared to the naturally disjunct eastern range. Males grew slightly faster than females. Animals from a catchment underlain by nutrient-poor quartzite rocks grew more slowly than those in a neighbouring catchment on richer dolerite. Individual growth histories varied considerably and suggest that there may be fast-growing and slow-growing animals within the population.
... Perca fluviatilis readily forms self-maintaining populations and has had severe effects on native fishes within this region (Morgan et al., 2002), as well as elsewhere (Wedderburn & Barnes, 2016). Along with their primary purpose of water supply, the region's reservoirs are important for recreational fisheries, including the two salmonids and an endemic crayfish, the smooth marron Cherax cainii (Duffy et al., 2014a, b;Beatty et al., 2016). To date, however, their potential to act as refuges for native fishes has not been formally assessed. ...
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Despite advances in statistical techniques for investigating population dynamics based on mark–recapture data, the majority of our understanding about demography and regulation comes from relatively few taxa. Most proposed generalisations about the association between demography and variation in population size are based on data from vertebrates, there are few sufficiently detailed invertebrate studies to examine whether these generalisations are widely supported. The population biology of freshwater invertebrates is especially poorly known. We present a large-scale mark–recapture study of an endemic freshwater crayfish from Madagascar (Astacoides granulimanus). Variation in density, caused by difference in fishing pressure due to local taboos, allowed us to investigate density-dependent regulation. We found evidence of density dependence in fecundity operating through the proportion of reproductive females by size but no significant evidence of density dependence in growth. Using a prospective analysis based on the elasticities from a size-structured matrix model, we found that both recruitment rates and survival rates of large individuals were strongly associated with deterministic population growth – a result that differs from generalisations drawn from vertebrate studies. A central assumption in mark–recapture studies is that handling does not affect mortality. By treating the number of times an individual was captured as an individual covariate, easily done using the freeware program MARK, we were able to test for, and take account of, handling-induced mortality. Our results show interesting similarities, and important differences, to generalisations based on vertebrate studies and emphasise the importance of population studies on poorly known taxa.
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The effect of temperature on survival, growth and reproductive parameters of Cherax quadricarinatus from a stage of early sexual differentiation to a stage of sexual maturity was investigated. Growth performance was expressed as specific growth rate (SGR) and growth increment (GI), while reproductive performance was evaluated in terms of the gonadosomatic index (GSI), mean oocyte diameter (MOD), proportion of mature vs. immature testicular lobes and structure of the vas deferens. The experiment consisted of males and females exposed separately to two treatments (water temperature at 27 and 30 °C) during a 360-day period. Survival was similar between treatments for each sex and between sexes for each treatment. Female growth, GSI and MOD did not differ between treatments. High temperature induced spawning in at least 20% of females. This treatment negatively affected growth of males, but they showed higher GSI and a greater proportion of mature testicular lobes, thus indicating an accelerated spermatogenesis. At 27 °C, males grew more than females from an approximate size of 15 g, confirming previous results about the differential growth of both sexes. We conclude that the long-term exposure to 30 °C is favorable for ovary maturation and spawning in females, but it clearly affects male somatic growth and consequently, the yields of culture. Both results are especially useful for the species culture in tropical countries. The effect of this water temperature on male reproductive performance deserves further research.
Article
The cultured freshwater crayfish Cherax destructor Clark has the largest distribution of any freshwater crayfish species in Australia. This study presents preliminary data on intraspecific variation in reproductive traits of C. destructor obtained from three populations under indoor hatchery conditions. Clutch size, measured as pleopodally attached eggs, and brood size, measured as newly independent juveniles, were positively correlated with crayfish weight. ANCOVA indicated significant differences between populations and between clutch and brood size. Based on size adjusted means, clutch size ranged from 360.6 to 593.4 and brood size from 311.4 to 384.5. Average brood size was 22.6% lower than average clutch size. Development time also differed amongst populations and was negatively correlated with temperature. Temperature adjusted mean development time ranged from an a minimum of 33.4 days to a maximum of 42.2 days. A strong inverse relationship between clutch/brood size and development time further highlighted the extent of life history differences amongst the crayfish populations. The implications of the increasing evidence for significant intraspecific variability within commercial species of Cherax in relation to aquaculture research and sustainable aquaculture are discussed.
Article
Handwritten thesis submitted in partial fulfillment of the requirements of the degree of M.D. Thesis (M.D.)--Albany Medical College, 1866.
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Duffy, R., Trinnie, F., Ryan, K., 2014. Licensed recreational marron fishery report. In: Fletcher, W.J., Santoro, K. (Eds.), Status Reports of the Fisheries and Aquatic Resources of Western Australia 2013/14: The State of the Fisheries. Department of Fisheries, Western Australia, pp. 41-51 http://www.fish.wa. gov.au/Documents/sofar/status reports of the fisheries and aquatic resources 2013-14.pdf.
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