Academic literature on the topic 'Mud crabs'
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Journal articles on the topic "Mud crabs"
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Poulin, Remington X., Serge Lavoie, Katherine Siegel, David A. Gaul, Marc J. Weissburg, and Julia Kubanek. "Chemical encoding of risk perception and predator detection among estuarine invertebrates." Proceedings of the National Academy of Sciences 115, no. 4 (January 8, 2018): 662–67. http://dx.doi.org/10.1073/pnas.1713901115.
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An effective strategy for prey to survive in habitats rich in predators is to avoid being noticed. Thus, prey are under selection pressure to recognize predators and adjust their behavior, which can impact numerous community-wide interactions. Many animals in murky and turbulent aquatic environments rely on waterborne chemical cues. Previous research showed that the mud crab, Panopeus herbstii, recognizes the predatory blue crab, Callinectus sapidus, via a cue in blue crab urine. This cue is strongest if blue crabs recently preyed upon mud crabs. Subsequently, mud crabs suppress their foraging activity, reducing predation by blue crabs. Using NMR spectroscopy- and mass spectrometry-based metabolomics, chemical variation in urine from blue crabs fed different diets was related to prey behavior. We identified the urinary metabolites trigonelline and homarine as components of the cue that mud crabs use to detect blue crabs, with concentrations of each metabolite dependent on the blue crab’s diet. At concentrations found naturally in blue crab urine, trigonelline and homarine, alone as well as in a mixture, alerted mud crabs to the presence of blue crabs, leading to decreased foraging by mud crabs. Risk perception by waterborne cues has been widely observed by ecologists, but the molecular nature of these cues has not been previously identified. Metabolomics provides an opportunity to study waterborne cues where other approaches have historically failed, advancing our understanding of the chemical nature of a wide range of ecological interactions.
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Sayeed, Zubayer, Hiroaki Sugino, Yutaro Sakai, and Nobuyuki Yagi. "Consumer Preferences and Willingness to Pay for Mud Crabs in Southeast Asian Countries: A Discrete Choice Experiment." Foods 10, no. 11 (November 19, 2021): 2873. http://dx.doi.org/10.3390/foods10112873.
Full textAbstract:
The mud crab (Scylla serrata) is an economically important species found in the mangroves and estuaries of tropical countries and is a popular seafood product in the coastal areas of Southeast Asian markets. The aim of this study is to identify factors affecting consumer preference of mud crabs, and to understand consumers’ willingness to pay (WTP) for these factors in a Singapore market where imported mud crabs from other Asian countries are sold. The results showed that the country of origin matters to participants, affecting purchasing decisions, and consumers were willing to pay approximately 16.48 SGD (11.49 USD, the average price of four shops: 35.55 USD/kg for one mud crab) more if the mud crabs were from Sri Lanka if compared with Indonesian or Cambodian mud crabs. Moreover, consumers were willing to pay 25.08 SGD (17.48 USD) more if the mud crabs were alive and 13.40 SGD (9.34 USD) less if the mud crabs were frozen compared with fresh, but not alive, mud crabs. Furthermore, consumers’ preference in mud crab was associated with the consumers’ religion. Some groups of consumers preferred female mud crabs with eggs over male mud crabs, while other groups preferred male crabs. The results identified diverse consumer preference of mud crabs and, therefore, could provide new insights that are useful for sustainable consumption of mud crabs in the region.
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Wan Yusof, Wan Roslina, Fasihuddin Badruddin Ahmad, and Mummedy Swamy. "A Brief Review on the Antioxidants and Antimicrobial Peptides Revealed in Mud Crabs from the Genus of Scylla." Journal of Marine Biology 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/1850928.
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Mud crab from the genus Scylla is also known as mangrove crab, which has been well-accepted as a good source of protein. Recently, the antioxidant properties present in mud crabs have been reported to have a part in the protection of cells against free radicals. Meanwhile, numerous antimicrobial peptides from mud crabs have managed to be characterized through the display of antimicrobial activities against Gram-positive and Gram-negative bacteria. Hence, this paper is an effort to collect recent literatures on antioxidant and antimicrobial properties in every part of mud crabs which include muscle tissue, hemolymph, and crab shell. Moreover, the effort to understand the biological properties of mud crabs is important to enhance its production in aquaculture industry. Therefore, this review hoped to attract the attention of natural product researchers to focus on the potential therapeutic applications of mud crabs.
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Samidjan, Istiyanto, Diana Rachmawati, and Putut Har Riyadi. "Development of Polyculture Engineering Technology on Milkfish and Mud Crab Farming." Pertanika Journal of Tropical Agricultural Science 45, no. 2 (March 22, 2022): 377–89. http://dx.doi.org/10.47836/pjtas.45.2.03.
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The current study aimed to evaluate the role of polyculture engineering technology on milkfish and mud crab farming and observe the growth and survivability of different milkfish and mud crab combinations. The study used milkfish, which was received artificial feed containing 35 % protein content enriched with vitamin E (3%/biomass/day). The study used completely randomized design with 4 treatments (n = 3): T1 = 5 milkfish + 5 mud crab, T2 = 10 milkfish + 5 mud crab, T3 = 5 milkfish + 10 mud crab, T4 = 10 milkfish + 10 mud crab. The following parameters were measured: absolute weight growth, survival rate, feed conversion rate (FCR), and water quality. The difference in the density of milkfish and mud crabs significantly affected (p < 0.05) the growth and survivability of milkfish and mud crabs. The polyculture cultivation system exhibited a significant increase in absolute weight growth of milkfish and mud crabs, which is the highest increase found in T4 treatment (187.85 g ± 0.9 g and 60.65 g ± 0.95 g, respectively). Meanwhile, the survival rate of milkfish and mud crab was 95% ± 0.3% and 95% ± 2.3%, respectively, followed by a lower FCR at T4 (1.54 ± 0.10). The water quality remained good for fish and mud crabs to survive. Milkfish and mud crab polyculture greatly affect the abundance of phytoplankton, demonstrating good community structure.
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Schweiss, Virginia R., and Chet F. Rakocinski. "Destabilizing effects on a classic tri-trophic oyster-reef cascade." PLOS ONE 15, no. 12 (December 15, 2020): e0242965. http://dx.doi.org/10.1371/journal.pone.0242965.
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How interactions among multiple predators affect the stability of trophic cascades is a topic of special ecological interest. To examine factors affecting the stability of the classic tri-trophic oyster reef cascade within a different context, configurations of three predators, including the Gulf toadfish, Gulf stone crab, and oystershell mud crab, were manipulated together with either oyster shell or limestone gravel substrate within a multiple predator effects (MPE) experiment. Additionally, a complimentary set of trait-mediated-indirect interaction (TMII) experiments examined the inhibition of oyster consumption relative to mud-crab size and top predator identity in the absence of other cues and factors. The classic tri-trophic cascade formed by the toadfish-mud crab-oyster configuration was potentially weakened by several interactions within the MPE experiment. Consumption of oysters and mud crabs by the intraguild stone crab was undeterred by the presence of toadfish. Although mud crab feeding was inhibited in the presence of both toadfish and stone crabs, estimated non-consumptive effects (NCEs) were weaker for stone crabs in the MPE experiment. Consequently, the total effect was destabilizing when all three predator species were together. Inhibition of mud crab feeding was inversely related to direct predation on mud crabs within the MPE experiment. Complimentary TMII experiments revealed greater inhibition of mud crab feeding in response to stone crabs under sparse conditions. TMII experiments also implied that inhibition of mud crab feeding could have largely accounted for NCEs relative to oysters within the MPE experiment, as opposed to interference by other mud crabs or top predators. An inverse relationship between mud crab size and NCE strength in the TMII experiment disclosed another potentially destabilizing influence on the tri-trophic-cascade. Finally, although habitat complexity generally dampened the consumption of oysters across MPE treatments, complex habitat promoted mud crab feeding in the presence of toadfish alone. This study underscores how ecological interactions can mediate trophic cascades and provides some additional insights into the trophic dynamics of oyster reefs for further testing under natural conditions.
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Duarte, Rafael C., Gustavo M. Dias, Augusto A. V. Flores, and Martin Stevens. "Different ontogenetic trajectories of body colour, pattern and crypsis in two sympatric intertidal crab species." Biological Journal of the Linnean Society 132, no. 1 (November 25, 2020): 17–31. http://dx.doi.org/10.1093/biolinnean/blaa168.
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Abstract Animals frequently exhibit great variation in appearance, especially in heterogeneous habitats where individuals can be concealed differentially against backgrounds. Although background matching is a common anti-predator strategy, gaps exist in our understanding of within- and among-species variation. Specifically, the drivers of changes in appearance associated with habitat use and occurring through ontogeny are poorly understood. Using image analysis, we tested how individual appearance and camouflage in two intertidal crab species, the mud crab Panopeus americanus and the mottled crab Pachygrapsus transversus, relate to ontogeny and habitat use. We predicted that both species would change appearance with ontogeny, but that resident mud crabs would exhibit higher background similarity than generalist mottled crabs. Both species showed ontogenetic changes; the mud crabs became darker, whereas mottled crabs became more green. Small mud crabs were highly variable in colour and pattern, probably stemming from the use of camouflage in heterogeneous habitats during the most vulnerable life stage. Being habitat specialists, mud crabs were better concealed against all backgrounds than mottled crabs. Mottled crabs are motile and generalist, occupying macroalgae-covered rocks when adults, which explains why they are greener and why matches to specific habitats are less valuable. Differential habitat use in crabs can be associated with different coloration and camouflage strategies to avoid predation.
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Dwi Hapsari, Trisnani, Azis Nur Bambang, Abdul Ghofar, and Aristi Dian Purnama Fitri. "Fishing pattern and environmentally friendly analysis on mud crab (Scylla spp.) fishery in Mojo mangrove ecosystem, Pemalang Regency, Central Java, Indonesia." E3S Web of Conferences 202 (2020): 02003. http://dx.doi.org/10.1051/e3sconf/202020202003.
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The high market demand of mud crabs has led to increase the capture so that their availability in the wild is threatened. The purpose of this study was to determine the fishing pattern of mud crabs and analyze the environmentally friendly of mud crab catching units in Mojo mangrove ecosystem. Data analysis used descriptive analysis to analyze the fishing pattern and analysis of the level of environmentally friendly based on nine FAO criteria. From the research it is known that the peak season of mud crabs fishing occurs during the west monsoon season and the usual season during the east monsoon season, while the famine season at the end of the east monsoon season. Observation results indicate that the majority of mud crabs caught are not in accordance with regulations (size <12 cm) with 70% of the total catch of mud crabs for soft shell crab farming needs. Based on environmental analysis of fishing gear, it is known that crab traps, trammel net, crabbing with a line and scoop net are environmentally friendly fishing gear with a score of 32.37, 26.81 and 32.40. However, there are criteria that do not meet environmentally friendly scores, namely the capture of mud crabs of a prohibited size and many non-target species caught with trammel net fishing gear.
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Munana, Nila, Irwani Irwani, and Widianingsih Widianingsih. "Pola Pertumbuhan Kepiting Bakau (Scylla serrata) Di Perairan Desa Bandengan Kendal." Journal of Marine Research 10, no. 1 (February 14, 2021): 14–22. http://dx.doi.org/10.14710/jmr.v10i1.28990.
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Kepiting bakau (Scylla serrata) merupakan jenis kepiting yang banyak ditemukan di beberapa daerah, salah satunya di Perairan Desa Bandengan, Kendal. Kepiting bakau setiap harinya ditangkap oleh nelayan, keadaan ini dapat mempengaruhi terhadap populasi kepiting bakau. Fase bulan dapat memberikan pengaruh terhadap kepiting bakau, seperti pada tingkah laku kepiting bakau. Tujuan dari penelitian ini yaitu untuk mengetahui pola pertumbuhan kepiting bakau pada fase bulan mati dan purnama di Perairan Desa Bandengan Kendal. Metode yang digunakan yaitu bersifat deskriptif eksploratif. Pengambilan data dilakukan sebanyak 6 kali periode pada 28 Desember 2019 – 9 Maret 2020, data dari kepiting bakau meliputi panjang karapas, lebar karapas, berat tubuh, jumlah kepiting bakau, dan parameter perairan. Jumlah kepiting bakau yang diperoleh selama penelitian sebanyak 212 ekor bulan mati dan 236 ekor bulan purnama. Hasil penelitian menunjukkan pola pertumbuhan kepiting bakau jantan bulan mati bersifat allometrik positif, sedangkan pada kepiting bakau betina bersifat allometrik negatif. Sedangkan, pada purnama 1 bersifat allometrik positif, bulan purnama 2 dan bulan purnama 3 bersifat allometrik negatif, sedangkan kepiting bakau betina bersifat allometrik negatif. Mud crab (Scylla serrata) is a type of crab that is found in several areas, one of which is in the waters of Bandengan Village, Kendal. Every day mud crabs are caught by fishermen, this situation can affect the mangrove crab population. The moon phase can affect mud crabs, such as the behavior of mud crabs. The purpose of this study was to determine the growth pattern of mud crabs in the new moon and full moon phases in the waters of the village of Bandengan, Kendal. The method used is descriptive exploratory. Data collection was carried out 6 times during the period on 28 December 2019 - 9 March 2020, data from mud crabs included carapace length, carapace width, body weight, number of mangrove crabs, and water parameters. The number of mud crabs obtained during the study was 212 new moons and 236 full moons. The results showed that the growth pattern of male mud crabs in the new moon was positive allometric, while the female mud crabs were negative allometric. Meanwhile, full moon 1 is allometric positive, full moon 2, and full moon 3 allometric negatives, while female mud crabs are allometric negative.
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Iromo, Heppi, Zainuddin, and dan Syawaluddin. "Study of Mud Crab Species (Scylla Spp.) In Brackish Waters North Kalimantan Province." IOP Conference Series: Earth and Environmental Science 1083, no. 1 (September 1, 2022): 012049. http://dx.doi.org/10.1088/1755-1315/1083/1/012049.
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Abstract Despite the importance of the mud crab species (genus Scylla) both in the development of crab culture in brackish waters, knowledge of mud crab species diversity for sustainable management throughout the coastal areas of North Kalimantan Province is still unclear. Therefore, this study was conducted to describe. The diversity of mud crabs in these waters is based on observations of crab morphology collected from five small islands in the coastal area of North Kalimantan. This study aims to identify the mud crab (Scylla spp.) species that live in the waters of North Kalimantan. It is hoped that this research can provide basic information about the types of mangrove crabs (Scylla spp.) that exist and live in the waters of North Kalimantan so that they can be used as a reference in the development and conservation of mud crab resources in North Kalimantan. This study uses a descriptive method to describe and describe the existing conditions in the field. Sampling was taken at random with different weights of 5 crabs/location at each high tide and carried out 2 times in every month. Sampling locations were carried out on several islands with many traditional ponds around the waters of North Kalimantan. The results of the study from Abstract100 samples of mud crabs showed that the types of mangrove crabs found in the waters of North Kalimantan were two species, namely Scylla serrata and Scylla tranquebarica.
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Altieri, Andrew H., and Andrew D. Irving. "Species coexistence and the superior ability of an invasive species to exploit a facilitation cascade habitat." PeerJ 5 (February 21, 2017): e2848. http://dx.doi.org/10.7717/peerj.2848.
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Facilitation cascades generated by co-occurring foundation species can enhance the abundance and diversity of associated organisms. However, it remains poorly understood how differences among native and invasive species in their ability to exploit these positive interactions contribute to emergent patterns of community structure and biotic acceptance. On intertidal shorelines in New England, we examined the patterns of coexistence between the native mud crabs and the invasive Asian shore crab in and out of a facilitation cascade habitat generated by mid intertidal cordgrass and ribbed mussels. These crab species co-occurred in low intertidal cobbles adjacent to the cordgrass–mussel beds, despite experimental findings that the dominant mud crabs can kill and displace Asian shore crabs and thereby limit their successful recruitment to their shared habitat. A difference between the native and invasive species in their utilization of the facilitation cascade likely contributes to this pattern. Only the Asian shore crabs inhabit the cordgrass–mussel beds, despite experimental evidence that both species can similarly benefit from stress amelioration in the beds. Moreover, only Asian shore crabs settle in the beds, which function as a nursery habitat free of lethal mud crabs, and where their recruitment rates are particularly high (nearly an order of magnitude higher than outside beds). Persistence of invasive adult Asian shore crabs among the dominant native mud crabs in the low cobble zone is likely enhanced by a spillover effect of the facilitation cascade in which recruitment-limited Asian shore crabs settle in the mid intertidal cordgrass–mussel beds and subsidize their vulnerable populations in the adjacent low cobble zone. This would explain why the abundances of Asian shore crabs in cobbles are doubled when adjacent to facilitation cascade habitats. The propensity for this exotic species to utilize habitats created by facilitation cascades, despite the lack of a shared evolutionary history, contributes to species coexistence and the acceptance of invasives into a diverse community.
Dissertations / Theses on the topic "Mud crabs"
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Churchill, Giles John. "An investigation into the captive spawning, egg characteristics and egg quality of the mud crab (Scylla serrata) in South Africa." Thesis, Rhodes University, 2004. http://hdl.handle.net/10962/d1015963.
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The source of a reliable supply of seed is one of the most important factors determining the success of aquaculture. At present mud crab culture is reliant on wild caught juveniles, which limits the expansion of mud crab farming globally. This, coupled with the paucity of knowledge of the spawning and egg characteristics of mud crabs, prompted the investigation into the captive spawning, incubation and egg quality of Scylla serrata in South Africa. A total of 112 mature females were caught from three estuaries in northern KwaZulu Natal and acclimated to captive conditions. Mature females were present in the estuaries throughout the year and ranged from 90 to 200 mm carapace width. Except for 40 crabs all the females spawned in captivity. On average spawning took place 38 ± 23 days after capture but was not dependent on crab size. Fecundity was significantly correlated to crab size (p = 0.026), with larger females producing more eggs. The average fecundity per batch was 5.79 ± 2.07 million eggs. Hatch success rate for all egg batches was high averaging 84 ± 6 %. Egg dropping occurred in all egg batches during incubation. On average 6.5 % of the egg mass was dropped during incubation. At the average temperature of 27⁰C eggs in the incubation system hatched within 292 ± 12 hours after extrusion. In-vitro incubation of eggs proved to be an ineffective means of incubating Scylla serrata eggs with a hatch success rate of only 25 ± 5 %. Egg quality was assessed both directly, using variables such as hatch success rate and hatch synchronicity and retrospectively by using stress tests and comparing survival of larvae from different coloured egg batches. Lipid class composition and fatty acid methyl ester content for 28 batches of eggs and 16 batches of larvae were analyzed. The biochemical composition of the egg was correlated to survival of larvae in the stress tests to ascertain if the lipid content of the eggs determines their quality. Stress tests were used to retrospectively assess egg quality. Four stressors were administered to newly hatched larvae and the LD50 values recorded. An average LD50 of 64 hours was recorded for the starvation tests, 40% for the salinity tests, 37 ppm for the formalin tests and 39.7 mg/l NH3 for the ammonia stress tests was recorded. Egg colour ranged from pale yellow to orange-red. Egg colour was not influenced by female size or the time the females spent in captivity prior to spawning. Egg colour can therefore not be used as an indicator of quality. The lipid profiles of newly extruded eggs had no effect on hatch synchronicity or hatch success rate. However, the stress tests identified female size (p ≤ 0.02), DHA content of the egg (p ≤ 0.02), Σ omega-3 fatty acids of eggs (p ≤ 0.02) and EPA content of eggs (p ≤ 0.007) as possible determinants of egg quality. Larger crabs tended to produce poorer quality eggs. Egg quality also decreased as the amount of DHA, EPA and the Σ omega-3 fatty acids decreased in the eggs. To summarize, the results of this study indicated that the following parameters affect egg quality - crab size, DHA, EPA and Σ omega-3 fatty acid content of eggs.
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Pavasovic, Marko. "Digestive profile and capacity of the mud crab (Scylla serrata)." Thesis, Queensland University of Technology, 2004. https://eprints.qut.edu.au/15973/1/Marko_Pavasovic_Thesis.pdf.
Full textAbstract:
Commercial farming of mud crab Scylla serrata is a significant industry throughout South East Asia. The limited scientific knowledge of mud crab nutritional requirements and digestive processes, however, is recognised as a
major constraint to the future growth of this industry. To better understand the
mechanisms of digestion in the mud crab we have analysed the diversity of digestive enzymes from the hepatopancreas. Significant protease, amylase,cellulase and xylanase activities were detected in soluble extracts from this
organ.
Temperature profiles for all enzymes were basically similar with optimal activities observed at 500C. Examination of pH tolerance revealed optimal activities for protease and amylase at pH 7.0 while optimal activities for
cellulase and xylanase were observed at pH 5.5. Under optimum conditions,protease and amylase activities were approximately two orders of magnitude greater than those seen for either cellulase or xylanase. Interestingly,
hepatopancreatic extracts were able to liberate glucose from either starch or carboxymethyl (CM)-cellulose suggesting that a range of carbohydrates may be utilised as energy sources. The effects of dietary carbohydrates on feed
digestibility, digestive enzyme levels and growth were also studied by inclusion of additional starch or CM-cellulose at the expense of casein in formulated diets. It was shown that amylase, cellulase and xylanase activities
in extracts from the hepatopancreas were highest in mud crabs fed diets containing 47% carbohydrate. Based on the findings, we suggest that the ability of the mud crab to modulate digestive enzyme activities may represent
a mechanism to maximise access to essential nutrients when the dietary profile changes.
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Pavasovic, Marko. "Digestive profile and capacity of the mud crab (Scylla serrata)." Queensland University of Technology, 2004. http://eprints.qut.edu.au/15973/.
Full textAbstract:
Commercial farming of mud crab Scylla serrata is a significant industry throughout South East Asia. The limited scientific knowledge of mud crab nutritional requirements and digestive processes, however, is recognised as a major constraint to the future growth of this industry. To better understand the mechanisms of digestion in the mud crab we have analysed the diversity of digestive enzymes from the hepatopancreas. Significant protease, amylase,cellulase and xylanase activities were detected in soluble extracts from this organ. Temperature profiles for all enzymes were basically similar with optimal activities observed at 500C. Examination of pH tolerance revealed optimal activities for protease and amylase at pH 7.0 while optimal activities for cellulase and xylanase were observed at pH 5.5. Under optimum conditions,protease and amylase activities were approximately two orders of magnitude greater than those seen for either cellulase or xylanase. Interestingly, hepatopancreatic extracts were able to liberate glucose from either starch or carboxymethyl (CM)-cellulose suggesting that a range of carbohydrates may be utilised as energy sources. The effects of dietary carbohydrates on feed digestibility, digestive enzyme levels and growth were also studied by inclusion of additional starch or CM-cellulose at the expense of casein in formulated diets. It was shown that amylase, cellulase and xylanase activities in extracts from the hepatopancreas were highest in mud crabs fed diets containing 47% carbohydrate. Based on the findings, we suggest that the ability of the mud crab to modulate digestive enzyme activities may represent a mechanism to maximise access to essential nutrients when the dietary profile changes.
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Gopurenko, David, and n/a. "Genetic Structure Within the Distribution of the Indo-West Pacific Mud Crab Scylla serrata (Forskal, 1775)." Griffith University. Australian School of Environmental Studies, 2003. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20030926.124631.
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It is often hypothesised that marine species with mobile planktonic phases are capable of widespread dispersal and may therefore be genetically homogenous throughout their distribution. Studies that have demonstrated positive correlation between duration of plankton phase and levels of gene flow reinforce the prediction that life history characteristics of marine species determine the potential extent of genetic and demographic connectivity throughout their distributions. This prediction has however been challenged by studies that have employed genetic markers highly sensitive to both historical and contemporary demographic changes. Disparities between dispersal potential and measured levels of gene flow have been demonstrated both among historically disconnected ocean basins and within semi-enclosed areas of strong hydraulic connectivity. These studies and others highlight a need for greater focus on factors that may influence population structure and distribution for marine species. In this thesis, I have examined genetic structure within and among populations of an estuarine species of mud crab Scylla serrata (Forskal, 1775) using a number of genetic markers and methods. The species is widely distributed throughout mangrove and estuarine habitats of the Indo - West Pacific (IWP); it is generally assumed that life-history characteristics of S. serrata promote high levels of population admixture and gene flow throughout its distribution. Alternatively, factors that have promoted population genetic structure for a variety of IWP marine species may also have affected S. serrata populations. By investigating genetic structure at several spatial scales of sampling, I was able to address a variety of hypotheses concerning the species distribution, dispersal, and genetic structure. Episodic changes to marine habitat and conditions experienced within the IWP during the Pleistocene may have affected genetic structure for a broad variety of marine taxa. The relative strength of this hypothesis may be assayed by comparative genetic studies of widespread IWP taxa with high dispersal capacity. In order to ascertain levels of historical and contemporary gene flow for S. serrata, I investigated the phylogeographic distribution of mitochondrial DNA haplotypes sampled throughout the species range. Adults were sampled from three west Indian ocean locations (N=21), six west Pacific sites (N=68), and two sites from northern eastern Australia (N=35). Temperature gradient gel electrophoresis and sequencing of 549 base pairs of the mitochondrial cytochrome oxidase I (COI) coding gene identified 18 distinct haplotypes. Apart from that seen in northern Australia, haplotype diversity was low (h < 0.36) at each of the locations. Total nucleotide diversity in the entire sample (excluding northern Australian locations) was also low (p = 0.09). Haplotypes clustered into two clades separated by approximately 2% sequence divergence. One clade was widespread throughout the IWP (clade 1) whereas the other was strictly confined to northern Australia (clade 2). Genealogical assessment of sequenced haplotypes relative to their distributions suggested that a historical radiation of clade 1 S. serrata throughout the IWP occurred rapidly and recently (<1Myr bp) from a west Pacific origin. The evidence of fixed unique haplotypes at the majority of locations suggested that contemporary maternal gene flow between trans-oceanic sites was limited. Contrary to reports for other widespread species of IWP taxa, there was no evidence of lengthy periods of regional separation between Indian from Pacific Ocean populations. However, results may indicate a separation of northern Australian crabs from other locations before and during the IWP radiation. I speculated that this isolation might have resulted in the formation of a new species of Scylla. Additional sampling of mud crabs from the Australian coastline allowed an examination of the diversity and distribution of clade 1 and 2 haplotypes among recently formed shelf-connected coastal locations, and across a historical bio-geographic barrier. Over 300 individuals were sampled from multiple locations within coastal regions (western, northern and eastern) of Australia and analysed for mutational differences at the COI gene. Analysis of molecular variance partitioned by sampling scale (Among regions, within regions, and within all locations) indicated mitochondrial haplotypes were structured regionally (P < 0.001), which contrasted with evidence of genetic panmixia within regions. Regional genetic structure broadly correlated with hydrological circulation, supporting the contention that release and transport of propagules away from the estuary may allow genetic connectivity among widespread shelf-connected S. serrata populations. That similar patterns of maternal gene flow were absent among trans-oceanic populations may indicate that the spatial scale of effective dispersal for this species is generally limited to areas of coastal shelf. The two clades of haplotypes were geographically separated either side of the Torres Strait, a narrow sea channel connecting the northern and eastern regions of coastal Australia. This pattern of historical genetic separation was concordant with a number of other marine species across northern Australia, and might indicate a shared history of vicariance induced by eustasy. Alternatively, differences in diversity and distribution of the clades may be evidence of two independent expansions of clade 1 and 2 crab populations into Australian regions following post-glacial estuary formation. Overall, despite evidence of genetic panmixia within extensive sections of the Australian distribution, there was also evidence of significant barriers to maternal gene flow with both shallow and deep regional phylogeographic assortment of mtDNA haplotypes. The presence of these barriers indicated both historical and contemporary factors have imposed limits to effective dispersal by this species among coastal habitats. A subset of the Australian sample (8 locations, N = 188) was also examined for variation at five microsatellite loci developed specifically here for S. serrata. I examined variation among samples at each of the loci to: a) independently verify regional structure among crab populations previously detected using the mtDNA analysis; b) test for evidence of co-distributed non-interbreeding stocks of S. serrata within Australian waters by examining samples for segregation of alleles within microsatellite loci concordant with the two mtDNA clades. The frequency and distribution of alleles for each of the highly polymorphic microsatellites were homogenous at all levels of sample partitioning and contrasted sharply with the instances of both weak and strong regional phylogeographic assortment of mtDNA haplotypes. These contrasting results between different genomic markers were examined in relation to the species life history, and to differences in mutational rate and inheritance of the genetic markers. Several hypotheses may explain the disparity, however it is most likely that rampant homoplasy and high rates of mutation at the microsatellite in conjunction with large Ne at locations may be concerted to delay equilibrium between genetic drift and migration among populations at these highly polymorphic nuclear markers. There was also no evidence that alleles at microsatellite loci were co-segregated with mtDNA clades and therefore no evidence of segregated breeding between the clades of crabs. Whether or not this result was also driven by homoplasy at the microsatellites remains unknown. Recently established mud crab populations (~ 3-4 years old) observed in a number of southwest Australian estuaries are almost 1000 kilometres south of their previously recorded distribution on the Western Australian coast. Colonisation of the southwest region may have occurred either by a natural range expansion from northwest Australian mud crab populations or by means of translocation from any number of mud crab sources within the Indo - West Pacific. I used mtDNA analysis to verify the species and determine the potential source population(s) of the colonists, by comparing sampled genetic material from the southwest (N = 32) against that previously described for the genus. I also compared levels of diversity at mtDNA and two microsatellite loci between the colonist and suspected source population(s) to qualitatively determine if the southwest populations experienced reductions in genetic diversity as a result of the colonisation process. All colonist samples had S. serrata mtDNA COI sequences identical to one previously described as both prevalent and endemic to northwest Australia. High levels of genetic diversity among source and colonist populations at two microsatellite loci contrasted to the mitochondrial locus which displayed an absence of variation among colonists compared to moderately diverse source populations. I argued that the southwest was recently colonised by large numbers of S. serrata propagules derived from the northwest of Australia, possibly due to an enhanced recruitment event coinciding with the reported strengthening of the Leeuwin Current during 1999. Contrasting levels of diversity among nuclear and mitochondrial loci may be attributed to a difference in response by the two genomes to the colonisation process. I predict that such differences may be generally prevalent among plankton-dispersed species. Finally, I discuss aspects of the species distribution and biogeography obtained as a composite of the various results and ideas expressed in this thesis. I propose that S. serrata populations in the IWP may have experienced several cycles of extinction and population retraction from temperate areas followed by subsequent periods of colonisation and rapid coastal expansion in response to the effects of glacial episodes on coastal habitats in the IWP. I propose that persistence of this species as remnant populations of clade 1 and 2 crabs at equatorial locations during low sea level stands provided source populations for later expansions by the species into a variety of coastal areas throughout the IWP. Further analysis is required to determine if mtDNA clade 1 and 2 crabs are non-interbreeding species of mud crab.
5
Hill, Jennifer Marie. "Predator biomass and habitat characteristics affect the magnitude of consumptive and non-consumptive effects (NCEs): experiments between blue crabs, mud crabs, and oyster prey." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41172.
Full textAbstract:
Recent research has focused on the non-lethal effects of predator intimidation and fear, dubbed non-consumptive effects (NCEs), in which prey actively change their behavior and habitat use in response to predator chemical cues. Although NCEs can have large impacts on community structure, many studies have ignored differences in predator population structure and properties of the natural environment that may modify the magnitude and importance of NCEs. Here, I investigated the roles of predator size and density (i.e. biomass), as well as habitat characteristics, on predator risk assessment and the magnitude of consumptive and NCEs using blue crabs, mud crabs, and oyster prey as a model system. Predation experiments between blue crabs and mud crabs demonstrated that blue crabs consume mud crabs; however, the consumptive effects were dependent upon blue crab body size and habitat type. When mud crabs were exposed to chemical cues from differing biomasses of blue crabs in laboratory mesocosms, mud crab activity and predation on oysters was decreased in response to high biomass treatments (i.e. large and multiple small blue crabs), but not to low biomass predators (i.e single small blue crab), suggesting that risk associated with predator size is perceptible via chemical cues and is based on predator biomass. Further experiments showed that the perception of risk and the magnitude of the NCEs were affected by the sensory cues available and the diet of the blue crab predator. The NCE based on blue crab biomass was also demonstrated in the field where water flow can disperse cues necessary for propagating NCEs. Properties of water flow were measured within the experimental design and during the experiment and confirmed cage environments were representative of natural conditions and that patterns in NCEs were not associated with flow characteristics. These results affect species conservation and commercial fisheries management and demonstrate that we cannot successfully predict NCEs without considering predator size structure and the contexts under which we determine predator risk.
6
Truong, Phuong Ha. "Nutrition and feeding behaviour in two species of mud crabs Scylla serrata and Scylla paramamosain." Thesis, Queensland University of Technology, 2008. https://eprints.qut.edu.au/20700/1/Phuong_Truong_Thesis.pdf.
Full textAbstract:
Mud crabs of the genus Scylla are widely exploited for aquaculture in the Asia- Pacific region. In the current study, a series of in vivo experiments were carried to assess the protein requirement, protein sparing effects of starch and the capacity of Scylla serrata to digest diets that contained different animal and plant-based feed meals and different levels and types of starch. Results from a protein requirement study indicated that juvenile S. serrata fed diets containing 45% or 55% protein demonstrated significantly higher growth responses than those fed the diet containing 25% protein. The subsequent study was carried out to determine if responses to dietary protein could be influenced by using purified wheat, potato, rice or corn starch to manipulate the gross energy level of fishmeal- based diets (18 or 15.5 MJ kg-1), i.e., to see if starch had a protein sparing effect in these animals. Overall, growth responses in this study appeared to be positively correlated with the level of protein in the diet with the highest growth rates achieved using diets containing 45% protein, regardless of the energy level of the diet. In addition, at a dietary protein level of 40% there was no evidence that the source of starch had any significant impact on growth performance or feed utilisation suggesting it had no protein sparing effect. By contrast, it was found that growth of juvenile S. serrata was strongly correlated with the intake of digestible dietary protein. The investigation of the capacity of sub-adult S. serrata to digest different animal and plant- based feed meals showed that apparent dry matter digestibility (ADMD) and apparent gross energy digestibility (AGED) values were not significant different for most selected feed meals (cotton seed, poultry, canola, fishmeal, soybean, and lupin meal). Apparent crude protein digestibility (ACPD) for all test feed meals were relatively high (86-96%). A subsequent study was carried out to determine if purified starch from different sources influenced the digestibility of fishmeal based diets. Overall, most diets containing starch were readily digested by mud crabs. In particular, there were no negative impacts on the digestibility of major nutrients (e.g. protein) observed following the inclusion of wheat, rice or corn starch in formulated feeds. Nevertheless, the apparent starch digestibility (ASD) of wheat starch decreased significantly as the inclusion level was increased from 15% to 60%, although there was no significant effect on ACPD values. At a 30% inclusion level, the ASD of diets containing different starches decreased in the order corn > wheat > potato = rice. Moreover, ACPD values were significantly higher for diets containing corn or rice starch than for those containing wheat or potato starch. The capacity of another species of mud crab commonly exploited for aquaculture in South East Asia, S. paramamosain, to digest the local plant-based ingredients (defatted soybean meal, rice bran, cassava and corn flour) was also conducted in Vietnam. Overall, the findings of this study showed that at a 30% inclusion level diets containing soybean meal or rice bran were well digested by mud crabs. In particular, the ACPD and AGED values for all diets containing soybean meal were not significantly different from the fishmeal based reference diet. Likewise, all digestibility values for the diet containing 30% rice bran were relatively high and not significantly different from the reference diet. By contrast, diets containing cassava flour appeared to be poorly utilised since their digestibility values for all parameters were lower than those from other testingredients. In summary, the apparent digestibility of dry matter, protein and energy was in the following order (from most to least digestible) soybean meal ~ rice bran > corn flour > cassava flour. In the next study the effects of attractants in diets (chicken meal, betaine, tuna oil and bait enhancer), temperature (26.5oC, 28.5oC and 30.5oC), sex (female and male) and size (small, medium and large) on feeding responses of S. serrata were investigated. Significant differences were observed in the behavioral responses of mud crabs to diets containing different attractants. Specifically, consumption of diets with chicken meal or betaine was significantly higher than for other treatments. With the exception of betaine, no significant difference in food consumption was observed when attractant inclusion levels were raised from 2% to 5%. Overall, small crabs consumed significantly more of the ration (as a percentage of body weight) than larger crabs. Temperature showed a significant impact on most behaviour of mud crabs, excepting continuation response and there was some evidence that females were significantly more active than males. Light intensity was considered as a main factor effect to crab response since there were extremely high percentage time of crab spent in half-shaded of the Y –maze which valued at 95.6%, 93.8 and 94.4% (corresponded to small, medium and large size respectively) in comparison to those of crabs spent in the unshaded side. Overall, the findings from these studies demonstrated that mud crabs have a high capacity to digest a range of plant based feed ingredients. In particular, soybean meal appeared to be well digested by both species of mud crabs examined. It was also shown that a range of purified starches were well digested by S. serrata although starch inclusion in diets did not appear to reduce the requirement for protein to promote growth. Subsequent attractant studies demonstrated that chicken meal and betaine produced significantly elevated feeding responses and food consumption when added to diets. Based on these results we propose that these ingredients can be utilised to increase the attractiveness and consumption of artificial mud crab feeds.
7
Truong, Phuong Ha. "Nutrition and feeding behaviour in two species of mud crabs Scylla serrata and Scylla paramamosain." Queensland University of Technology, 2008. http://eprints.qut.edu.au/20700/.
Full textAbstract:
Mud crabs of the genus Scylla are widely exploited for aquaculture in the Asia- Pacific region. In the current study, a series of in vivo experiments were carried to assess the protein requirement, protein sparing effects of starch and the capacity of Scylla serrata to digest diets that contained different animal and plant-based feed meals and different levels and types of starch. Results from a protein requirement study indicated that juvenile S. serrata fed diets containing 45% or 55% protein demonstrated significantly higher growth responses than those fed the diet containing 25% protein. The subsequent study was carried out to determine if responses to dietary protein could be influenced by using purified wheat, potato, rice or corn starch to manipulate the gross energy level of fishmeal- based diets (18 or 15.5 MJ kg-1), i.e., to see if starch had a protein sparing effect in these animals. Overall, growth responses in this study appeared to be positively correlated with the level of protein in the diet with the highest growth rates achieved using diets containing 45% protein, regardless of the energy level of the diet. In addition, at a dietary protein level of 40% there was no evidence that the source of starch had any significant impact on growth performance or feed utilisation suggesting it had no protein sparing effect. By contrast, it was found that growth of juvenile S. serrata was strongly correlated with the intake of digestible dietary protein. The investigation of the capacity of sub-adult S. serrata to digest different animal and plant- based feed meals showed that apparent dry matter digestibility (ADMD) and apparent gross energy digestibility (AGED) values were not significant different for most selected feed meals (cotton seed, poultry, canola, fishmeal, soybean, and lupin meal). Apparent crude protein digestibility (ACPD) for all test feed meals were relatively high (86-96%). A subsequent study was carried out to determine if purified starch from different sources influenced the digestibility of fishmeal based diets. Overall, most diets containing starch were readily digested by mud crabs. In particular, there were no negative impacts on the digestibility of major nutrients (e.g. protein) observed following the inclusion of wheat, rice or corn starch in formulated feeds. Nevertheless, the apparent starch digestibility (ASD) of wheat starch decreased significantly as the inclusion level was increased from 15% to 60%, although there was no significant effect on ACPD values. At a 30% inclusion level, the ASD of diets containing different starches decreased in the order corn > wheat > potato = rice. Moreover, ACPD values were significantly higher for diets containing corn or rice starch than for those containing wheat or potato starch. The capacity of another species of mud crab commonly exploited for aquaculture in South East Asia, S. paramamosain, to digest the local plant-based ingredients (defatted soybean meal, rice bran, cassava and corn flour) was also conducted in Vietnam. Overall, the findings of this study showed that at a 30% inclusion level diets containing soybean meal or rice bran were well digested by mud crabs. In particular, the ACPD and AGED values for all diets containing soybean meal were not significantly different from the fishmeal based reference diet. Likewise, all digestibility values for the diet containing 30% rice bran were relatively high and not significantly different from the reference diet. By contrast, diets containing cassava flour appeared to be poorly utilised since their digestibility values for all parameters were lower than those from other testingredients. In summary, the apparent digestibility of dry matter, protein and energy was in the following order (from most to least digestible) soybean meal ~ rice bran > corn flour > cassava flour. In the next study the effects of attractants in diets (chicken meal, betaine, tuna oil and bait enhancer), temperature (26.5oC, 28.5oC and 30.5oC), sex (female and male) and size (small, medium and large) on feeding responses of S. serrata were investigated. Significant differences were observed in the behavioral responses of mud crabs to diets containing different attractants. Specifically, consumption of diets with chicken meal or betaine was significantly higher than for other treatments. With the exception of betaine, no significant difference in food consumption was observed when attractant inclusion levels were raised from 2% to 5%. Overall, small crabs consumed significantly more of the ration (as a percentage of body weight) than larger crabs. Temperature showed a significant impact on most behaviour of mud crabs, excepting continuation response and there was some evidence that females were significantly more active than males. Light intensity was considered as a main factor effect to crab response since there were extremely high percentage time of crab spent in half-shaded of the Y –maze which valued at 95.6%, 93.8 and 94.4% (corresponded to small, medium and large size respectively) in comparison to those of crabs spent in the unshaded side. Overall, the findings from these studies demonstrated that mud crabs have a high capacity to digest a range of plant based feed ingredients. In particular, soybean meal appeared to be well digested by both species of mud crabs examined. It was also shown that a range of purified starches were well digested by S. serrata although starch inclusion in diets did not appear to reduce the requirement for protein to promote growth. Subsequent attractant studies demonstrated that chicken meal and betaine produced significantly elevated feeding responses and food consumption when added to diets. Based on these results we propose that these ingredients can be utilised to increase the attractiveness and consumption of artificial mud crab feeds.
8
Overton, Julia Lynne. "Morphometric, genetic and reproductive characteristics of mud crabs (genus Scylla de Haan, 1833) from Southeast Asia." Thesis, University of Stirling, 2000. http://hdl.handle.net/1893/2599.
Full textAbstract:
The edible mud crab, genus Scylla, is important to fisheries and aquaculture throughout the Indo Pacific region, but its taxonomic status has been confused for decades and a new classification has only recently been proposed. This project was undertaken to investigate the species status of mud crabs in Southeast Asia, with a view to deciding whether two sympatric morphs of Scylla found in Ban Don Bay, Surat Thani Province, Thailand, are two separate species. A further aim was to elucidate any possible pre-zygotic reproductive isolating mechanisms (RIMs) and ecological features that maintain the apparent sympatry between these two morphs. Mud crabs were collected from a primary site (Surat Thani, Thailand) as well as from six other locations in Thailand, Vietnam, Malaysia and Bangladesh. Crab samples from the latter sites were used selectively to provide a comparison to the primary study site. Descriptive taxonomy, multivariate morphometrics and allozyme electrophoresis were used to a) determine the number of species present within the crab samples collected; b) to ascertain which species they represent; c) to discover any geographical variation between locations sampled; d) to produce a possible phylogeny that summaries the relationship between Scylla species; and e) to look for pre-zygotic RIMs to explain the sympatry of the two morphs in Surat Thani. Findings from the present study reinforce the recent revision of the taxonomy of the genus Scylla into four species, S. serrata, S. olivacea, S. tranquebarica and S. paramamosain and provides new information on two of the four species which are dominant within Southeast Asia, including Ban Don Bay, Surat Thani Province, S. paramamosain and S. olivacea. Population studies showed both genetic and morphological differentiation between conspecific populations of S. paramamosain and S. olivacea, indicating stock structure for each species, although there is some disparity between morphological and genetic distances for S. paramamosain. This is discussed in relation to the effects of larval dispersal mechanisms and the subsequent recruitment of juvenile crabs. Phylogenetic interpretation of both genetic and morphological characters revealed that both S. serrata and S. olivacea are the most diverged of the four Scylla species; however, the direction of evolution is open to interpretation and the evidence for either S. olivacea or S. serrata as the more primitive species are discussed. Reproductive studies on the two mud crab species found in Surat Thani revealed no physical barrier to hybridization. Both species have a protracted breeding season which continues throughout the year. However, the size at first sexual maturity was significantly smaller for S. olivacea when compared to S. paramamosain. This and other potential mechanisms that may maintain these two species sympatrically are discussed. The clarification of four Scylla species, and the establishment of diagnostic genetic and morphological characters that can be used to identify them, means that research can now focus on both the ecology and life history of these closely related species. Such information is needed urgently with respect to fisheries management as well as to understanding the environmental requirements of each species in order to develop their potential for aquaculture.
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Gopurenko, David. "Genetic Structure Within the Distribution of the Indo-West Pacific Mud Crab Scylla serrata (Forskal, 1775)." Thesis, Griffith University, 2003. http://hdl.handle.net/10072/367817.
Full textAbstract:
It is often hypothesised that marine species with mobile planktonic phases are capable of widespread dispersal and may therefore be genetically homogenous throughout their distribution. Studies that have demonstrated positive correlation between duration of plankton phase and levels of gene flow reinforce the prediction that life history characteristics of marine species determine the potential extent of genetic and demographic connectivity throughout their distributions. This prediction has however been challenged by studies that have employed genetic markers highly sensitive to both historical and contemporary demographic changes. Disparities between dispersal potential and measured levels of gene flow have been demonstrated both among historically disconnected ocean basins and within semi-enclosed areas of strong hydraulic connectivity. These studies and others highlight a need for greater focus on factors that may influence population structure and distribution for marine species. In this thesis, I have examined genetic structure within and among populations of an estuarine species of mud crab Scylla serrata (Forskal, 1775) using a number of genetic markers and methods. The species is widely distributed throughout mangrove and estuarine habitats of the Indo - West Pacific (IWP); it is generally assumed that life-history characteristics of S. serrata promote high levels of population admixture and gene flow throughout its distribution. Alternatively, factors that have promoted population genetic structure for a variety of IWP marine species may also have affected S. serrata populations. By investigating genetic structure at several spatial scales of sampling, I was able to address a variety of hypotheses concerning the species distribution, dispersal, and genetic structure.
Episodic changes to marine habitat and conditions experienced within the IWP during the Pleistocene may have affected genetic structure for a broad variety of marine taxa. The relative strength of this hypothesis may be assayed by comparative genetic studies of widespread IWP taxa with high dispersal capacity. In order to ascertain levels of historical and contemporary gene flow for S. serrata, I investigated the phylogeographic distribution of mitochondrial DNA haplotypes sampled throughout the species range. Adults were sampled from three west Indian ocean locations (N=21), six west Pacific sites (N=68), and two sites from northern eastern Australia (N=35). Temperature gradient gel electrophoresis and sequencing of 549 base pairs of the mitochondrial cytochrome oxidase I (COI) coding gene identified 18 distinct haplotypes. Apart from that seen in northern Australia, haplotype diversity was low (h < 0.36) at each of the locations. Total nucleotide diversity in the entire sample (excluding northern Australian locations) was also low (p = 0.09). Haplotypes clustered into two clades separated by approximately 2% sequence divergence. One clade was widespread throughout the IWP (clade 1) whereas the other was strictly confined to northern Australia (clade 2). Genealogical assessment of sequenced haplotypes relative to their distributions suggested that a historical radiation of clade 1 S. serrata throughout the IWP occurred rapidly and recently (<1Myr bp) from a west Pacific origin. The evidence of fixed unique haplotypes at the majority of locations suggested that contemporary maternal gene flow between trans-oceanic sites was limited. Contrary to reports for other widespread species of IWP taxa, there was no evidence of lengthy periods of regional separation between Indian from Pacific Ocean populations. However, results may indicate a separation of northern Australian crabs from other locations before and during the IWP radiation. I speculated that this isolation might have resulted in the formation of a new species of Scylla. Additional sampling of mud crabs from the Australian coastline allowed an examination of the diversity and distribution of clade 1 and 2 haplotypes among recently formed shelf-connected coastal locations, and across a historical bio-geographic barrier. Over 300 individuals were sampled from multiple locations within coastal regions (western, northern and eastern) of Australia and analysed for mutational differences at the COI gene. Analysis of molecular variance partitioned by sampling scale (Among regions, within regions, and within all locations) indicated mitochondrial haplotypes were structured regionally (P < 0.001), which contrasted with evidence of genetic panmixia within regions. Regional genetic structure broadly correlated with hydrological circulation, supporting the contention that release and transport of propagules away from the estuary may allow genetic connectivity among widespread shelf-connected S. serrata populations. That similar patterns of maternal gene flow were absent among trans-oceanic populations may indicate that the spatial scale of effective dispersal for this species is generally limited to areas of coastal shelf. The two clades of haplotypes were geographically separated either side of the Torres Strait, a narrow sea channel connecting the northern and eastern regions of coastal Australia. This pattern of historical genetic separation was concordant with a number of other marine species across northern Australia, and might indicate a shared history of vicariance induced by eustasy. Alternatively, differences in diversity and distribution of the clades may be evidence of two independent expansions of clade 1 and 2 crab populations into Australian regions following post-glacial estuary formation. Overall, despite evidence of genetic panmixia within extensive sections of the Australian distribution, there was also evidence of significant barriers to maternal gene flow with both shallow and deep regional phylogeographic assortment of mtDNA haplotypes. The presence of these barriers indicated both historical and contemporary factors have imposed limits to effective dispersal by this species among coastal habitats. A subset of the Australian sample (8 locations, N = 188) was also examined for variation at five microsatellite loci developed specifically here for S. serrata. I examined variation among samples at each of the loci to: a) independently verify regional structure among crab populations previously detected using the mtDNA analysis; b) test for evidence of co-distributed non-interbreeding stocks of S. serrata within Australian waters by examining samples for segregation of alleles within microsatellite loci concordant with the two mtDNA clades. The frequency and distribution of alleles for each of the highly polymorphic microsatellites were homogenous at all levels of sample partitioning and contrasted sharply with the instances of both weak and strong regional phylogeographic assortment of mtDNA haplotypes. These contrasting results between different genomic markers were examined in relation to the species life history, and to differences in mutational rate and inheritance of the genetic markers. Several hypotheses may explain the disparity, however it is most likely that rampant homoplasy and high rates of mutation at the microsatellite in conjunction with large Ne at locations may be concerted to delay equilibrium between genetic drift and migration among populations at these highly polymorphic nuclear markers. There was also no evidence that alleles at microsatellite loci were co-segregated with mtDNA clades and therefore no evidence of segregated breeding between the clades of crabs. Whether or not this result was also driven by homoplasy at the microsatellites remains unknown. Recently established mud crab populations (~ 3-4 years old) observed in a number of southwest Australian estuaries are almost 1000 kilometres south of their previously recorded distribution on the Western Australian coast. Colonisation of the southwest region may have occurred either by a natural range expansion from northwest Australian mud crab populations or by means of translocation from any number of mud crab sources within the Indo - West Pacific. I used mtDNA analysis to verify the species and determine the potential source population(s) of the colonists, by comparing sampled genetic material from the southwest (N = 32) against that previously described for the genus. I also compared levels of diversity at mtDNA and two microsatellite loci between the colonist and suspected source population(s) to qualitatively determine if the southwest populations experienced reductions in genetic diversity as a result of the colonisation process. All colonist samples had S. serrata mtDNA COI sequences identical to one previously described as both prevalent and endemic to northwest Australia. High levels of genetic diversity among source and colonist populations at two microsatellite loci contrasted to the mitochondrial locus which displayed an absence of variation among colonists compared to moderately diverse source populations. I argued that the southwest was recently colonised by large numbers of S. serrata propagules derived from the northwest of Australia, possibly due to an enhanced recruitment event coinciding with the reported strengthening of the Leeuwin Current during 1999. Contrasting levels of diversity among nuclear and mitochondrial loci may be attributed to a difference in response by the two genomes to the colonisation process. I predict that such differences may be generally prevalent among plankton-dispersed species. Finally, I discuss aspects of the species distribution and biogeography obtained as a composite of the various results and ideas expressed in this thesis. I propose that S. serrata populations in the IWP may have experienced several cycles of extinction and population retraction from temperate areas followed by subsequent periods of colonisation and rapid coastal expansion in response to the effects of glacial episodes on coastal habitats in the IWP. I propose that persistence of this species as remnant populations of clade 1 and 2 crabs at equatorial locations during low sea level stands provided source populations for later expansions by the species into a variety of coastal areas throughout the IWP. Further analysis is required to determine if mtDNA clade 1 and 2 crabs are non-interbreeding species of mud crab.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Australian School of Environmental Studies
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Vu, Ngoc Ut. "Assessment of the feasibility of stock enhancement of mud crabs, Scylla paramamosain, in the Mekong Delta, Vietnam." Thesis, Bangor University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273571.
Full textBooks on the topic "Mud crabs"
1
Why the crawfish lives in the mud. Gretna, La: Pelican Pub., 2009.
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2
Ingle, R. W. Lobsters, mud shrimps and anomuran crabs: Keys and notes for the identification of the species. Shrewsbury [England]: published for the Linnean Society of London and the Estuarine and Coastal Sciences Assoc. by Field Studies Council, 2004.
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3
Eating mud crabs in Kandahar: Stories of food during wartime by the world's leading correspondents. Berkeley: University of California Press, 2011.
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Mwaluma, James. Culture experiment on the growth and production of mud crabs, mullets, milkfish and prawns in Mtwapa mangrove system, Kenya. [Zanzibar]: WIOMSA, 2003.
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5
Southeast Asian Fisheries Development Center. Aquaculture Dept. Library & Documentation Services. Mud crab bibliography. Tiobauan, Iloilo, Philippines: Brackishwater Aquaculture Information System, SEAFDEC Aquaculture Dept., 1985.
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Mud crab abstracts. Tigbauan, Iloilo, Philippines: Brackishwater Aquaculture Information System, SEAFDEC Aquaculture Dept., 1989.
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Barrett, Robert G. Mud crab boogie. Pymble, Sydney, NSW: HarperCollins, 1998.
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Kathirvel, M. Mud crab culture in India. Chennai: Central Institute of Brackishwater Aquaculture, 2004.
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Beautiful swimmers: Watermen, crabs, and the Chesapeake Bay. New York: Penguin Books, 1987.
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Warner, William W. Beautiful swimmers: Watermen, crabs, and the Chesapeake Bay. Boston: Little, Brown, 1994.
Find full textBook chapters on the topic "Mud crabs"
1
Ingle, Ray. "Mud Lobsters (Thalassinoidea)." In Crayfishes, Lobsters and Crabs of Europe, 75–82. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-011-5872-5_7.
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2
Le Vay, Lewis, Vu Ngoc Ut, and David A. Jones. "Seasonal abundance and recruitment in an estuarine population of mud crabs, Scylla paramamosain, in the Mekong Delta, Vietnam." In Advances in Decapod Crustacean Research, 231–39. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-017-0645-2_25.
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Paterson, Brian D., and David L. Mann. "Mud Crab Aquaculture." In Recent Advances and New Species in Aquaculture, 115–35. Oxford, UK: Wiley-Blackwell, 2011. http://dx.doi.org/10.1002/9781444341775.ch4.
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Li, Yuanyou, Chunxiang Ai, and Lijie Liu. "Mud Crab, Scylla paramamosain China's Leading Maricultured Crab." In Aquaculture in China, 226–33. Chichester, UK: John Wiley & Sons Ltd, 2018. http://dx.doi.org/10.1002/9781119120759.ch3_4.
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Warne, Kennedy. "The Old Man and the Mud Crab." In Let Them Eat Shrimp, 38–43. Washington, DC: Island Press/Center for Resource Economics, 2011. http://dx.doi.org/10.5822/978-1-61091-024-8_4.
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Komissarov, Serguei, and Yuri Lyubarsky. "MHD Simulations of Crab’s Jet and Torus." In Virtual Astrophysical Jets, 107–13. Dordrecht: Springer Netherlands, 2004. http://dx.doi.org/10.1007/978-1-4020-2664-5_12.
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Hallerman, Eric M., David N. Hata, Michael S. Eackles, and Timothy L. King. "Population Genetics and Movement Show Metapopulation Dynamics of Mid-Atlantic Region Horseshoe Crabs." In International Horseshoe Crab Conservation and Research Efforts: 2007- 2020, 41–57. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-82315-3_4.
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Huq, Khandaker Anisul, S. M. Bazlur Rahaman, and A. F. M. Hasanuzzaman. "Mud Crab Culture as an Adaptive Measure for the Climatically Stressed Coastal Fisher-Folks of Bangladesh." In Environmental Management and Governance, 175–98. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-06305-8_7.
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Murugan, Kadarkarai, Lan Wang, Jiang Shiou Hwang, Jaganathan Anitha, Devakumar Dinesh, Pandiyan Amuthavalli, Murugan Vasanthakumaran, Suresh Kumar, and Hans-Uwe Dahms. "Use of Bio-fabricated Silver Nanocomposite Capped with Mud Crab Shell (Scylla serrata) Chitosan for Water Purifications and Sustainable Management of Mosquito Vectors at Stagnant Water System in the Semiarid Zone of Tamil Nadu, India." In Water Resources in Arid Lands: Management and Sustainability, 195–202. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-67028-3_16.
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"INTRODUCTION: THE NAME OF THE THIRD CHICKEN: Kosovo." In Eating Mud Crabs in Kandahar, 1–6. University of California Press, 2019. http://dx.doi.org/10.1525/9780520949683-001.
Full textConference papers on the topic "Mud crabs"
1
Perea, Rossian V., and Jesus Paolo B. Cullado. "ICT-Assisted Growth Management System for Mud crabs (ICT-AGMAS): Deployment and Evaluation." In 2022 International Conference on Emerging Techniques in Computational Intelligence (ICETCI). IEEE, 2022. http://dx.doi.org/10.1109/icetci55171.2022.9921381.
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Perea, Rossian V., and Enrique D. Festijo. "Analytics Platform for Morphometric Grow out and Production Condition of Mud Crabs of the Genus Scylla with K-Means." In 2021 4th International Conference of Computer and Informatics Engineering (IC2IE). IEEE, 2021. http://dx.doi.org/10.1109/ic2ie53219.2021.9649163.
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Padaunan, Novianto, Zahir Zainuddin, and Muhammad Niswar. "Mobile Application For Mud Crab Weight Estimation." In 2018 2nd East Indonesia Conference on Computer and Information Technology (EIConCIT). IEEE, 2018. http://dx.doi.org/10.1109/eiconcit.2018.8878611.
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Ali, Rozniza, and M. Syafieq M. Fauzi. "The use of Local Binary Pattern (LBP) feature extraction Members of the mud crab genus Scylla." In ICAAI 2019: 2019 The 3rd International Conference on Advances in Artificial Intelligence. New York, NY, USA: ACM, 2019. http://dx.doi.org/10.1145/3369114.3369117.
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de Jager, O. C. "Gamma-rays from the Crab Nebula and other plerions—testing MHD models." In The international symposium on high energy gamma-ray astronomy. AIP, 2001. http://dx.doi.org/10.1063/1.1370788.
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Xiaoyun Lin, Yuanyu Cao, Zhongbao Li, Wenjing Li, Guiling Zhang, Zhanlin Wang, Ning Wu, Zhihong Zhang, and Xinjiang Tian. "Notice of Retraction: Isolation and characterization of ten new polymorphic microsatellite loci of the mud crab, Scylla paramamosain." In 2010 2nd Conference on Environmental Science and Information Application Technology (ESIAT 2010). IEEE, 2010. http://dx.doi.org/10.1109/esiat.2010.5568726.
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Khornchatri, Kanjana. "Distribution of Gamma-aminobutyric acid (GABA) in the central nervous system of the male mud crab, Scylla olivacea." In European Microscopy Congress 2020. Royal Microscopical Society, 2021. http://dx.doi.org/10.22443/rms.emc2020.34.
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Sances, Anthony. "Injury Criteria of Child and Adult Dummies." In ASME 1999 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1999. http://dx.doi.org/10.1115/imece1999-0485.
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Abstract Human injury tolerance is difficult because of physical differences between humans and animals, dummies and cadaver tissue. Human volunteer testing has been done but at sub injurious levels (Stapp, 1986 and Ewing, 1972). Considerable biomechanical engineering and tissue studies exist for the adult human cadaver however little is available for the pediatric population (Kumaresan, 1999). A number of dummies have recently been made available principally for airbag testing to bridge the gap between the 50 percentile hybrid III male dummy and the 95 percentile male dummy. (Kleinberger. 1998) The air bag dummies including the 12-month old CRABI dummy, 3-year old Hybrid III dummy, 6-year old Hybrid III dummy, the Hybrid III small female, Hybrid II mid-size male and 95 percentile large male are discussed.
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Perea, Rossian V., and Enrique D. Festijo. "Analysis of the use of Analytics Platform for the Commercial Value of Mud crab Production using Non-parametric Model." In 2022 IEEE 12th Annual Computing and Communication Workshop and Conference (CCWC). IEEE, 2022. http://dx.doi.org/10.1109/ccwc54503.2022.9720844.
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Mirzoyan, Razmik, Giacomo D'Amico, Giovanni Ceribella, Yuki Iwamura, Takayuki Saito, and Masahiro Teshima. "Absolute Calibration of Mid to Large Size IACTs with P1/P2 of the Crab Pulsar." In 37th International Cosmic Ray Conference. Trieste, Italy: Sissa Medialab, 2021. http://dx.doi.org/10.22323/1.395.0883.
Full textReports on the topic "Mud crabs"
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Mud Crab Fattening and Post-Harvest Handling Instruction Manual. Wildlife Conservation Society, 2021. http://dx.doi.org/10.19121/2021.report.39691.
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