Australian Red Claw Crayfish Cherax Research Articles

Biotechnology of Australian red-claw crayfish (Cherax quadricarinatus) juvenile ongrowing in recirculating aquaculture system

As a result of the work done, the biotechnology of growing Australian red claw crayfish (Cherax quadricarinatus) juvenile in recirculating aquaculture system facilities was developed. The research work was carried out in the laboratory of advanced technologies in aquaculture on the basis of the business incubator the Federal State-Funded Educational Institution of Higher Education “Kuban State University”. The composition of the material base necessary for the implementation of biotechnology is determined, growth rates are determined, an optimal diet is formed and optimal planting densities are determined. For the working process two recirculating aquaculture system units were used. As food we used: minced fish, sturgeon food, artemia nauplii, oatmeal, frozen bloodworm, dried gammarus. During 80 days, decades-long survival varied from 83.6 to 91.8%. The average weight of individuals had changed from 0.03 to 5.10 g. The coefficient of variation of this feature was in the permissible range and increased from 9.1 to 22.6%. The total feed coefficient at a cost of 3387.3 g of feed per increase of 1347.7 g of biomass composed 2.5 units. Using the data obtained, it is possible to make primary calculations when organizing the cultivation of ARCC juveniles.

The first occurrence of the Australian redclaw crayfish Cherax quadricarinatus (von Martens, 1868) in the contiguous United States

The first occurrence of the Australian redclaw crayfish Cherax quadricarinatus (von Martens, 1868) in the contiguous United States

Prospects for the cultivation of Australian red claw crayfish Cherax quadricarinatus on warm waters of energy facilities

River crayfish - a delicious food product. On the caloric content (72kcal/100g), the content of fats (2.83%), protein (17.13%) and vitamins of group B (thiamine, riboflavin, etc.), crayfish are not inferior to freshwater fish, and by a number of parameters exceed them. Meat of crayfish is rich in sulfur, phosphorus, iron, cobalt, magnesium, fluorine, potassium, selenium, chromium, calcium and vitamins of group B (B12, B6, B2, B1, B9,), C, E, K, PP and D. There is practically no cholesterol in it, but there are a lot of organic acids. A promising target of cultivation, both in Russia and abroad, is currently the Australian red-cheeked crayfish Cherax quadricarinatus. It is cultivated in such countries as: China, Brazil, Ecuador, America, and others. Currently, in spite of the presence of active crayfish farms in Russia, the biotechnology of growing Cherax quadricarinatus is not sufficiently developed. The main advantages of Cherax quadricarinatus over crayfish that live in our region (Astacus leptodactylus, Astacus astacus, etc.) are: high growth rate, tolerance to water quality, lack of pelagic larva stage. It is advisable to use cooler reservoirs of energy objects for growing valuable warm water aquaculture objects, since the water temperature of these reservoirs is higher than the natural. Energy can contribute to the development of warm water crayfish farming both in the Republic of Tatarstan and in Russia as a whole. Due to the excessive heat that enters the natural reservoirs from energy facilities, an excellent opportunity appears in the absence of the cost of expensive equipment, to grow valuable products. According to expert estimates, the cultivation of crayfish is 5-6 times more profitable than fish.

Crustacean nuclear localization signals help facilitating the delivery of DNA into Australian red-claw crayfish cells

Crustacean aquaculture is rapidly expanding, and demands are supported through the application of novel technologies. One such application is the oral administration of foreign DNA, which expresses genes of interest to promote growth, health and superior quality traits. To date, there has not been any report of a viable method for large-scaled oral delivery of foreign DNA into crustaceans, although these methodologies have expanded in utilization across many plant and animal species. DNA delivery requires a thorough understanding of the transcription machinery of the host species to which it is administered. This knowledge is still unavailable in crustaceans, where the mechanism to enable nuclear entry is obscure. In this study we utilized a bioinformatics approach to shortlist Nuclear Localisation Signals (NLSs), and designed crustacean-specific NLSs to enhance the delivery of DNA into the nucleus via active transport. The NLS-plasmid complex, carrying GFP and IAG genes was transfected into Australian redclaw crayfish (Cherax quadricarinatus) primary cultured cells, resulting in protein expression of the introduced genes. These NLSs also increased the transfection efficiency in mammalian cells from 0.6% to 9% in suboptimal conditions. Hence, this integrated approach of bioinformatics and in vitro studies could help in developing a novel biotechnology to enable the large-scaled oral DNA delivery in the crustacean aquaculture industry.

РОСТ МОЛОДИ АВСТРАЛИЙСКОГО РАКА CHERAX QUADRICARINATUS В ИНДУСТРИАЛЬНЫХ УСЛОВИЯХ В ЗАВИСИМОСТИ ОТ ТЕМПЕРАТУРЫ СРЕДЫ

The article presents study results of the influence of water temperature on the growth and evolution of juveniles of the Australian red claw crayfish ( Cherax quadricarinatus ) in circulating water supply systems. There have been analyzed 750 specimens of crayfish larvae and 150 juveniles, which were contained in large fish tanks, each with 200 l capacity. Each fish tank had autonomous system water purification and thermal regulation: 24.0; 28.0 and 31.0°С. Duration of test made 63 days. It was found that maximum efficiency of juvenile-stock rearing of crayfish can be achieved under the temperature 25.0-27.0°С. Growth rate of crayfish decreased and their survivalship was lower than threshold values under the temperature 30.0°С and higher. Insignificant changes of the temperature regime of the Australian crayfish juvenile habitat within the bounds of biological normal interval exert a significant impact on the results of their breeding both at an early nascent stage, beginning from the first larval stages, and more recent stages of the ontogenesis. It has been proved that water temperature has effect not only on the weight and linear growth, but also on the survivalship of the Australian crayfish juvenile. It has been observed that under 30.0°С survivalship of young crayfish decreased in two times during the first five days in circulating water supply units. For this reason in providing of industrial rearing of early juveniles of the Australian crayfish it should be taken into account that planned withdrawal at the first two-three months could make up to 50% from the initial number of larvae.

Distribution and establishment of the alien Australian redclaw crayfish, Cherax quadricarinatus, in South Africa and Swaziland.

BackgroundThe Australian redclaw crayfish (Cherax quadricarinatus, von Martens), is native to Australasia, but has been widely translocated around the world due to aquaculture and aquarium trade. Mostly as a result of escape from aquaculture facilities, this species has established extralimital populations in Australia and alien populations in Europe, Asia, Central America and Africa. In South Africa, C. quadricarinatus was first sampled from the wild in 2002 in the Komati River, following its escape from an aquaculture facility in Swaziland, but data on the current status of its populations are not available.MethodsTo establish a better understanding of its distribution, rate of spread and population status, we surveyed a total of 46 sites in various river systems in South Africa and Swaziland. Surveys were performed between September 2015 and August 2016 and involved visual observations and the use of collapsible crayfish traps.ResultsCherax quadricarinatus is now present in the Komati, Lomati, Mbuluzi, Mlawula and Usutu rivers, and it was also detected in several off-channel irrigation impoundments. Where present, it was generally abundant, with populations having multiple size cohorts and containing ovigerous females. In the Komati River, it has spread more than 112 km downstream of the initial introduction point and 33 km upstream of a tributary, resulting in a mean spread rate of 8 km year−1 downstream and 4.7 km year−1 upstream. In Swaziland, estimated downstream spread rate might reach 14.6 km year−1. Individuals were generally larger and heavier closer to the introduction site, which might be linked to juvenile dispersal.DiscussionThese findings demonstrate that C. quadricarinatus is established in South Africa and Swaziland and that the species has spread, not only within the river where it was first introduced, but also between rivers. Considering the strong impacts that alien crayfish usually have on invaded ecosystems, assessments of its potential impacts on native freshwater biota and an evaluation of possible control measures are, therefore, urgent requirements.

Wild populations of the invasive Australian red claw crayfish Cherax quadricarinatus (Crustacea, Decapoda) near the northern coast of Jalisco, Mexico: a new fishing and profitable resource

The red claw crayfish Cherax quadricarinatus is native to freshwater habitats of northern Australia and Papua New Guinea. Its high reproductive and adaptive capacity in different environments allows it to be cultivated, where escaped individuals have established wild populations in countries far from their natural range. In the late 90’s and beginning of the 21st century, this crayfish was introduced illegally along the coast of southern Jalisco. Mismanagement led to escape and dispersion. Currently there are wild crayfish in the Cajón de Peñas Reservoir and surrounding streams in northern Jalisco, Mexico. The aim of this study was to evaluate the presence of C. quadricarinatus in fisheries in this area of Jalisco and analyze its importance in generating economic benefits for fishermen, comparing these results with those of the fishery for M. americanum, whose fishery is traditional. To catch specimens, traps were set for 24 h in the La Sanja Stream and the Cajón de Peñas Reservoir. The results of the survey showed that C. quadrica rinatus is an important part of the crustacean catch in this area: 32% of the total catch in the stream corresponded to C. quadricarinatus and the rest to M. americanum. While 85% of the catch in the dam corresponded to C. quadricarinatus, only 15% referred to M. americanum. Crayfish fishing in the reservoir is now an important part of the productive activity of local families dependent on fishing. The ecological consequences of wild crayfish proliferation remain to be studied.

Presence of the Australian redclaw crayfish Cherax quadricarinatus (von Martens, 1868) (Parastacidae, Astacoidea) in a freshwater system in the Caribbean drainage of Costa Rica

Presence of the Australian redclaw crayfish Cherax quadricarinatus (von Martens, 1868) (Parastacidae, Astacoidea) in a freshwater system in the Caribbean drainage of Costa Rica

Transcriptomic characterization and curation of candidate neuropeptides regulating reproduction in the eyestalk ganglia of the Australian crayfish, Cherax quadricarinatus.

The Australian redclaw crayfish (Cherax quadricarinatus) has recently received attention as an emerging candidate for sustainable aquaculture production in Australia and worldwide. More importantly, C. quadricarinatus serves as a good model organism for the commercially important group of decapod crustaceans as it is distributed worldwide, easy to maintain in the laboratory and its reproductive cycle has been well documented. In order to better understand the key reproduction and development regulating mechanisms in decapod crustaceans, the molecular toolkit available for model organisms such as C. quadricarinatus must be expanded. However, there has been no study undertaken to establish the C. quadricarinatus neuropeptidome. Here we report a comprehensive study of the neuropeptide genes expressed in the eyestalk in the Australian crayfish C. quadricarinatus. We characterised 53 putative neuropeptide-encoding transcripts based on key features of neuropeptides as characterised in other species. Of those, 14 neuropeptides implicated in reproduction regulation were chosen for assessment of their tissue distribution using RT-PCR. Further insights are discussed in relation to current knowledge of neuropeptides in other species and potential follow up studies. Overall, the resulting data lays the foundation for future gene-based neuroendocrinology studies in C. quadricarinatus.

Stochastic analysis of production dynamics of male and female redclaw crayfish (Cherax quadricarinatus) reared under commercial intensive cultivation

AbstractWe used a stochastic model to simulate, over time, total biomass production of male and female Australian redclaw crayfish (Cherax quadricarinatus), so as production of commercial‐sized crayfish (40–60 and 61–90 g). The model was calibrated with a database from an intensive commercial farm. Results showed that uncertainty in obtaining production of the 61–90 g grade diminished with time. In the case of 40–60 g grade and total biomass, uncertainty was minimal at 69 days (males 40–60 g grade), 84 days (females 40–60 g grade), 92 days (male total biomass) and 94 days (female total biomass). The model predicted that, at harvesting time, there is 95% confidence intervals that males produce 2.96–3.29 t ha−1 (mean = 3.13 t ha−1) and females produce 2.49–2.72 t ha−1 (mean = 2.60 t ha−1), of biomass, closely approximating biomass production registered in the database. When increasing sample size from one pond to 16 ponds, variability in production was reduced in 75.5% (males) and 65.2% (females). Sensitivity analysis showed that individual weight, and percentages corresponding to the total commercial population and the 40–60 g size were the variables mostly influencing the variance of yields. The results showed that the dynamics of production of commercial biomass strongly differ among ponds. We conclude that the model is a useful tool for analysis of the stochastic processes governing production dynamics of redclaw crayfish biomass.

Australian red claw crayfish (Cherax quadricarinatus) is susceptible to yellow head virus (YHV) infection and can transmit it to the black tiger shrimp (Penaeus monodon)

Abstract The Australian red claw crayfish (RCC), Cherax quadricarinatus was introduced in Thailand more than two decades ago for culture in freshwater areas where marine penaeid shrimp are also frequently farmed. Despite many reports of various diseases that occur in RCC in Australia (both from natural habitats and from farms), there have been no reports of its diseases when farmed in Thailand. Our recent study on RCC cultured in Thailand revealed that it is susceptible to WSSV infection and that it can transmit the virus to native shrimp species such as the black tiger shrimp ( Penaeus monodon ). Thus, we decided to continue by testing whether RCC were also susceptible to endemic yellow head virus (YHV) and also capable of transmitting it to black tiger shrimp (BTS). Using three different exposure methods (injection, feeding and cohabitation) with test RCC, we obtained no YHV pathology or positive immunoreactions using monoclonal antibodies against all 3 structural proteins of YHV. By contrast, a standard RT-PCR assay targeting the RdRp gene of YHV with RNA extracted from the experimentally exposed red claw did give positive results. In addition, BTS that tested negative for YHV and were then cohabitated (separated by a plastic net) with RT-PCR positive RCC became infected with YHV and died, exhibiting the severe histopathology typical of yellow head disease. This was confirmed by strong positive immunohistochemical reactions for YHV and positive RT-PCR results. These results suggested that the experimentally exposed RCC were susceptible to YHV infection at sufficient level to allow transmission to BTS but not sufficient to allow detection by the standard histological methods currently used. Statement of relevance The loss due to the yellow head virus is second only to that of white spot syndrome virus (WSSV) in South East Asia. Despite the continual search for its reservoir, since its discovery in the early 1990s, the reservoir for YHV-1 (the most virulent strain of YHV found in Thailand) has still not been identified. Outbreaks of the virus in cultivated, exotic whiteleg shrimp P. vannamei that originate from SPF stocks known to be free of the virus, suggesting that the outbreaks occur via horizontal transmission from an environmental source. Based on our results, exotic red claw crayfish ( Cherax quadricarinatus ) that are cultured in fresh water areas where marine penaeid shrimp are also frequently farmed should be added to the list of potential reservoirs. Red claw crayfish, from our results, is susceptible but highly tolerant to the virus. Infected red claw crayfish could transmit the virus without showing any signs of yellow head disease. These facts make them perfect carrier for the virus. YHV infection in red claw crayfish could be detected by RT-PCR only not by routine histology or immunohistochemistry.

Alien invasions and livelihoods: Economic benefits of invasive Australian Red Claw crayfish in Jamaica

Invasive species have caused widespread economic and environmental disruption, which have been widely studied. However, their potential benefits have received much less attention. If invasive species contribute to livelihoods, their eradication may negatively impact wellbeing. Failing to value these benefits may lead to an undervaluation of invaded ecosystems. We assess the potential economic benefits of an invasive species within an artisanal fishery in Jamaica. We monitored catches over 259 fisherman-days, and conducted 45 semi-structured interviews, with 76 fishermen. We show that the invasive Australian Red Claw crayfish (Cherax quadricarinatus) is an important source of income for fishermen within the Black River Lower Morass of Jamaica and supplement incomes during periods when native shrimp (Macrobrachium spp.) catches decline. We also show that full-time fishermen and those who have no alternative occupations expend the greatest fishing effort. We use the intra-annual variation of fishermen's harvest effort between seasons (when catch per unit effort changes) as a proxy for dependence. Using this measure, we found that the least wealthy appear to be the most dependent on fishing, and consequently benefit the most from the invasive crayfish. Our results demonstrate the importance of considering the potential benefits of invasive species within integrated landscape management.

Effects on growth, survival, body composition, processing traits and water quality when feeding a diet without vitamin and mineral supplements to Australian red claw crayfish (Cherax quadricarinatus) grown in ponds

To be profitable, producers must reduce diet costs, which can be as high as 80% of the variable costs of an aquaculture expense. As vitamin and mineral premixes represent a significant cost, eliminating addition of these premixes could reduce diet costs if no adverse effects were observed for growth and production parameters. A 105-day feeding trial was conducted with juvenile Australian red claw crayfish (Cherax quadricarinatus) to evaluate the effects of growth, survival, body composition, processing traits and water quality when red claw were fed a supplemental diet containing 28% crude protein (CP) without vitamin and mineral premixes (and supplemented alfalfa hay) compared with red claw fed a diet (control diet) containing 42% CP, vitamin and mineral premixes, and with supplemented alfalfa hay, and compared with red claw only fed alfalfa hay when grown in ponds. Juvenile red claw (mean weight of 15.7 ± 1.0 g) were randomly stocked into nine 0.02-ha ponds at a rate of 640 per pond (3.2 per m2), and each treatment was used in three ponds. There were two feedings per day, each consisting of one-half of the total daily ration. At harvest, individual weight, percentage weight gain, specific growth rate, survival and total yield of red claw fed a control diet was significantly higher (P < 0.05) (83.0 g, 398%, 1.53% day−1, 65.1%,and 1708 kg ha−1 respectively) compared with red claw only fed alfalfa hay (44.9 g, 202%, 1.04% day−1, 30.3% and 431 kg ha−1, respectively), but not different (P > 0.05) from red claw fed the supplemental diet without vitamin and mineral premixes (76.2 g, 367%, 1.47% day−1, 57.2% and 1378 kg ha−1). There were no significant differences (P > 0.05) in feed conversion ratio (FCR) among treatments, which averaged 5.0 (based on prepared diet input). These results indicate that vitamin and mineral supplementation in a diet is not necessary when diet containing 28% CP and alfalfa hay are used in combination for pond grown red claw. These results may help reduce diet costs and possibly increase producers’ profits which might allow for industry expansion.

An androgenic gland membrane-anchored gene associated with the crustacean insulin-like androgenic gland hormone

Crustacean male sexual differentiation is governed by the androgenic gland (AG) and specifically by the secreted insulin-like AG hormone (IAG), thus far identified in several decapod species including the Australian red claw crayfish Cherax quadricarinatus (termed Cq-IAG). While a few insulin-like AG genes have been identified in crustaceans, other AG-specific genes have not been documented until now. In the present study, we describe the recent identification of a non-IAG AG-specific transcript obtained from the C. quadricarinatus AG cDNA library. This transcript, termed C. quadricarinatus membrane-anchored AG-specific factor (Cq-MAG), was fully sequenced and found to encode a putative product of 189 amino acids including a signal anchoring peptide. Expression of a recombinant GFP fusion protein lacking the signal anchor encoding sequence dramatically affected recombinant protein localization pattern. While the expression of the deleterious fusion protein was observed throughout most of the cell, the native GFP::Cq-MAG fusion protein was observed mainly surrounding the periphery of the nucleus, demonstrating an endoplasmic reticulum (ER)-like localization pattern. Moreover, co-expression of the wild-type Cq-MAG (fused to GFP) and the Cq-IAG hormone revealed that these peptides indeed co-localize. This study is the first to report a protein specifically associated with the insulin-like AG hormone in addition to the finding of another AG-specific transcript in crustaceans. Previous knowledge suggests that insulin/insulin-like factor secretion involves tissue-specific transcripts and membrane-anchored proteins. In this regard, Cq-MAG's tissue specificity, anchoring properties and intracellular co-localization with Cq-IAG suggest that it may play a role in the processing and secretion of this insulin-like AG hormone.

Stimulation of molt by RNA interference of the molt-inhibiting hormone in the crayfish Cherax quadricarinatus

In crustaceans, molting is known to be under the control of neuropeptide hormones synthesized and secreted from the eyestalk ganglia. While the role of molt-inhibiting hormone (MIH) in regulating molting has been described in several species using classical methods, an in vivo specific MIH targeted manipulation has not been described yet. In the present study, an MIH cDNA was isolated and sequenced from the eyestalk ganglia of the Australian freshwater red claw crayfish Cherax quadricarinatus (Cq) by 5′ and 3′ RACE. We analyzed the putative Cq-MIH based on sequence homology, a three dimensional structure model and transcript’s tissue specificity. We further examined the involvement of Cq-MIH in the control of molt in the crayfish through RNAi by in vivo injections of Cq-MIH double-stranded RNA, which resulted in, similarly to eyestalk ablation, acceleration of molt cycles. This acceleration was reflected by a significant reduction (up to 32%) in molt interval and an increased rate in molt mineralization index (MMI), which correlated with the induction of ecdysteroid hormones compared to control. Altogether, this study provides a proof of function for the involvement of the Cq-MIH gene in molt regulation in the crayfish.

Histological and Ultrastructural Studies on the Male Reproductive System and Spermatogenesis in the Red Claw Crayfish, Cherax quadricarinatus

Abstract Relative to other economically important marine animals, there is limited knowledge of the reproductive characteristics of the male Australian red claw crayfish Cherax quadricarinatus. In this study, the structure of the male reproductive system of C. quadricarinatus and the progression of spermatogenesis were examined histologically and using transmission electron microscopy (TEM). The male reproductive system of C. quadricarinatus is composed of paired testes, vasa deferentia, and genital appendixes. Each testis has a non-branched collecting duct and numerous attached seminal acini. Spermatogenesis occurs mainly in the seminal acini. Germ cell development is synchronous within each acinus, but not between different acini. Spermatids, formed after meiosis, undergo a complicated metamorphosis until the aflagellate spermatozoa are finally formed. Early in the metamorphosis, a highly convoluted membrane lamellar system is assembled in the cytoplasm as the chromatin begins to condense. The convolute...

Ornamental trade as a pathway for Australian ­redclaw crayfish introduction and establishment

AB Aquatic Biology Contact the journal Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AB 12:69-79 (2011) - DOI: https://doi.org/10.3354/ab00324 Ornamental trade as a pathway for Australian ­redclaw crayfish introduction and establishment Christina C. Belle1,2, Jason Q. H. Wong3, Darren C. J. Yeo1, S. H. Tan3, Heok H. Tan3, Esther Clews1, Peter A. Todd1,* 1Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore 2Tropical Marine Science Institute, National University of Singapore, 18 Kent Ridge Road, Singapore 119227, Singapore 3Raffles Museum of Biodiversity Research, Department of Biological Sciences, National University of Singapore, 6 Science Drive 2, Singapore 117546, Singapore *Corresponding author. Email: dbspat@nus.edu.sg ABSTRACT: The ornamental trade is one of the major vectors of freshwater animal species translocation worldwide. The Australian redclaw crayfish Cherax quadricarinatus was brought into Singapore through the trade and culture of aquarium specimens during the late 1980s. From 2000 to the present, redclaw crayfish have been observed in at least 3 of Singapore’s 13 reservoirs, including 2 inland reservoirs in the Central Catchment Nature Reserve (CCNR). The current paper presents the first in situ population data of feral C. quadricarinatus populations originating from ornamental trade and includes updated distribution records in Singapore based on recent surveys and museum samples. We report a C. quadricarinatus range expansion in 2 additional reservoirs (1 coastal and 1 inland), and the presence of multiple size cohorts confirms the establishment of reproducing populations in 2 coastal reservoirs and 1 CCNR reservoir. This is alarming as the current distribution borders Singapore’s oldest and arguably most important nature reserve (Bukit Timah Nature Reserve: BTNR) and encircles the single remaining substantial freshwater swamp forest in the country (Nee Soon). The Nee Soon swamp forest and BTNR have extremely high conservation value as both areas together harbour the richest native freshwater fauna and flora of the island. Therefore, any range expansion of C. quadricarinatus in Singapore may have severe impacts on its native freshwater fauna and demands immediate attention. As C. quadricarinatus is one of the many invasive freshwater ­species occurring from the aquarium trade in Singapore, we argue that trade control might prevent ­further establishment of ornamentals. KEY WORDS: Cherax quadricarinatus · Invasive · Ornamental trade · Reproducing feral populations · Singapore reservoirs Full text in pdf format PreviousNextCite this article as: Belle CC, Wong JQH, Yeo DCJ, Tan SH, Tan HH, Clews E, Todd PA (2011) Ornamental trade as a pathway for Australian ­redclaw crayfish introduction and establishment. Aquat Biol 12:69-79. https://doi.org/10.3354/ab00324 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AB Vol. 12, No. 1. Online publication date: April 06, 2011 Print ISSN: 1864-7782; Online ISSN: 1864-7790 Copyright © 2011 Inter-Research.

Feral populations of the Australian Red-Claw crayfish (Cherax quadricarinatus von Martens) in water supply catchments of Singapore

The Red-Claw crayfish, Cherax quadricarinatus von Martens, is native to freshwater habitats of northern Australia and Papua New Guinea. Owing to its large size and suitability for aquaculture, C. quadricarinatus has been widely translocated around the world. Unfortunately, C. quadricarinatus is also recognised as invasive, having already established feral populations in South Africa, Mexico, Jamaica and Puerto Rico. The hardiness and conspicuous colouration of C. quadricarinatus has also made it popular in the aquarium trade worldwide, including Singapore. Here, we report the establishment of feral populations of C. quadricarinatus in the water supply catchments of Singapore.

Influence of Gender and Spawning on Meat Quality of Australian Red Claw Crayfish (Cherax quadricarinatus) Stored at 2 °C

ABSTRACT: Shell‐on tails of male (M), nonspawning female (F), and spawning female (SF) Australian red claw crayfish (Cherax quadricarinatus) (n= 270) were aerobically stored at 2 °C up to 10 d to monitor meat quality changes under a retail condition. Percentage protein of SF muscle was higher (P &lt; 0.05) and moisture and ash content lower (P &lt; 0.05) than those of M and F muscles. The pH of muscle changed during storage, with SF generally having a lower value than M or F (P &lt; 0.05). Lipid oxidation increased during the 1st 5 d and no significant difference existed between the 3 muscle groups. Cooking yield of SF (91.72%) at 10 d was significantly lower than that of M (96.25%) or F (97.81%), and its muscle shear force was also higher (P &lt; 0.05) than M at 0, 3, 5, and 7 d and than F at 5 and 7 d. Sensory panel results (cooked meat tenderness, juiciness) were significantly correlated with instrumental results (shear force, cooking yield), with SF showing a lower meat tenderness, juiciness, and overall acceptability than M and F samples.

Effects of feeding practical diets containing different protein levels, with or without fish meal, on growth, survival, body composition and processing traits of male and female Australian red claw crayfish (Cherax quadricarinatus) grown in ponds

Four practical diets containing 2% of crude protein (CP) (180 and 280 g kg )1 ), with or without menhaden fish meal (FM), were fed to Australian red claw Cherax quadricarinatus during a 97-day feeding trial. Growth, survival, body composition and processing traits of pond-cultured red claw were determined. Juvenile red claw (mean individual weight of 5.75 ± 3.3 g) were randomly stocked into twelve 0.04-ha ponds at a rate of 1000 per pond (25 000 ha )1 ), and each diet was fed to three ponds. At harvest, the final mean weight of red claw fed Diet 4 (0 g kg )1 FM and 280 g kg )1 CP) and Diet 3 (113 g kg )1 FM and 280 g kg )1 CP) was significantly (P < 0.05) higher (62.4 and 58.5 g, respectively) than red claw fed Diet 1 (73 g kg )1 FM and 180 g kg )1 CP; 51.7 g) and Diet 2 (0 g kg )1 FM and 180 g kg )1 CP; 53.0 g). Red claw fed diets containing 280 g kg )1 CP, with or without FM, had significantly higher percent weight gain (894 and 959%, respectively) compared to red claw fed 180 g kg )1 CP, with or without FM (778 and 799%, respectively). Feed conversion ratio, percent survival, and total yield among treatments, which averaged 3.55, 65.2%, and 724 kg ha )1 overall, were not significantly different. Results from this study indicate that pond-cultured red claw stocked at 25 000 ha )1 can be fed a practical diet containing 280 g kg )1 CP with 0 g kg )1 FM if a combination of plant-protein ingredients (soybean meal, distillers dried grains with solubles, and milo) is added; however, if the percentage of dietary protein level is 180 g kg )1 , growth is reduced even if FM is added at 73 g kg )1 of the diet. Use