Journal articles on the topic 'Crabs'
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1
Qomariyah, L., R. Z. Wicaksono, K. C. Nugroho, and W. Setioko. "The proportion of the egg berried female crabs and the hatching time based on differences in the eggs colour of the blue swimming crab in the crab box apartment." IOP Conference Series: Earth and Environmental Science 1251, no. 1 (October 1, 2023): 012056. http://dx.doi.org/10.1088/1755-1315/1251/1/012056.
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Abstract Fishermen in Pagagan Village who get the egg-berried female (EBF) of blue swimming crabs can store them in the Crab Box Apartment that has been provided on the coast so that the crabs incubate their eggs. The placement of EBF crabs in the crab box apartment showed fishermen actively participating in sustainable crab management. The EBF crabs are quite varied, especially in egg colour (yellow, orange, brown, and grey). This study used descriptive analysis to identify the EBF crab’s hatching time based on the egg colour that is incubated in the crab apartment. The result showed that the EBF crabs with yellow eggs have an average hatching time of more than 7 days. The orange eggs are, on average 5 days, the brown eggs are about 3 days, and the grey eggs are only 1 day. These hatching time records can also improve the implementation of the crab box apartment, which is a way to minimize the presence of EBF crabs in the supply chain and increase compliance, which leads to sustainability.
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Ramadhan, F., R. Z. Wicaksono, and D. Darmawan. "Growth and survival rate of blue swimming crab enlargement in the south coast of Pamekasan, Madura Island." IOP Conference Series: Earth and Environmental Science 1251, no. 1 (October 1, 2023): 012055. http://dx.doi.org/10.1088/1755-1315/1251/1/012055.
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Abstract Indonesia has fishery commodities favoured by the world market, especially blue swimming crab fisheries. Fishing activities that continue to increase have caused the blue swimming crab population in nature tend to decrease. Therefore, it is necessary to develop aquaculture in ponds and coastal waters. However, blue swimming crab enlargement has technological constraints that have yet to be widely known by the wider community. The study aimed to determine the survival rate of blue swimming crabs in coastal waters using ponds conducted in Pamekasan, East Java. The parameters measured were the width of the blue swimming crab’s carapace using a ruler and the growth of the blue swimming crab’s weight using a digital scale. The experimental results on blue swimming crabs obtained an absolute growth of 9.8 cm and a survival rate of 3.96%. The high rate of cannibalism in blue swimming crabs can indicate the cause of the low survival rate of blue swimming crabs. This research is expected to increase the choice of blue swimming crab enlargement to reduce the pressure of catches and be another alternative to reduce the level of blue swimming crab fishing in nature.
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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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Susanto, Adi, Hery Sutrawan Nurdin, Ririn Irnawati, Mochammad Riyanto, Mohammad Ependi, Fahresa Nugraheni Supadminingsih, Asep Hamzah, and Hendrawan Syafrie. "PENGEMBANGAN DESAIN PINTU MASUK BUBU LIPAT BERDASARKAN ASPEK TINGKAH LAKU RAJUNGAN." Marine Fisheries : Journal of Marine Fisheries Technology and Management 12, no. 2 (November 1, 2021): 125–36. http://dx.doi.org/10.29244/jmf.v12i2.36616.
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Blue swimming crab fishing using collapsible traps is widely used by fishermen because its caught live crabs and high selectivity. However, the passive fishing operation causes its low fishing productivity. The success of crabs fishing using folding traps is influenced by the suitability of the entrance design used. The size of the net and the inclination angle that are not by the crab's behavior will cause the crab to fail to be caught. This study aims to determine the more effective entrance design for catching crabs using the collapsible trap. The study was conducted in a laboratory using three mesh sizes, including 1.00, 1.25, and 1.50 inches with 30°, 40°, and 50° inclination angles. Each treatment combination uses different individual crabs. The study was conducted at night in an aquarium equipped with an infrared camera. Differences in mesh size and angle of inclination affect the crab's success rate and crawling speed in crossing the net field. The results showed that the highest percentage of crabs that successfully crossed the net field was obtained using a 1.25-inch mesh with an angle of 40°. The highest average crawling speed was also obtained at the same mesh size and angle of inclination. The use of a 1.25-inch mesh with an angle of 40° is expected to increase the effectiveness of catching crabs with folding traps.
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Munroe, DM, TM Grothues, NE Cleary, J. Daw, and S. Estrada. "Oyster aquaculture does not impede spawning beach access for Atlantic horseshoe crabs Limulus polyphemus." Aquaculture Environment Interactions 12 (February 27, 2020): 81–90. http://dx.doi.org/10.3354/aei00351.
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Farms for eastern oyster Crassostrea virginica, which are commonly located along shallow estuarine shores of the eastern USA, use a range of farm equipment and require regular access to care for and harvest oyster livestock. In some cases, these farms are located in areas used by Atlantic horseshoe crabs Limulus polyphemus as they come ashore during spring to spawn. The sandy shores of the Delaware Bay host the largest spawning aggregations of this species in the world. Limited studies have examined interactions between horseshoe crabs and intertidal oyster farms, and concern has been raised about the horseshoe crab’s ability to traverse oyster farms to reach spawning habitat. This study examines potential farm interactions with horseshoe crabs in Delaware Bay during the 2018 and 2019 crab spawning season. Our studies included a range of experiments and surveys during high and low tide to observe crab abundance and behavior at rack-and-bag oyster farm and non-farm sites. In all cases, results indicated that crabs can successfully traverse rack-and-bag farms and reach spawning beaches. Crabs do not differentially use farm versus non-farm areas, and crab behavior is relatively unaltered by farm gear. These results provide important context for developing frameworks for managing ecological interactions among farms and wildlife species of concern.
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Wang, Han, Hong Zhu, Lishuai Bi, Wenjie Xu, Ning Song, Zhiqiang Zhou, Lanying Ding, and Maohua Xiao. "Quality Grading of River Crabs Based on Machine Vision and GA-BPNN." Sensors 23, no. 11 (June 3, 2023): 5317. http://dx.doi.org/10.3390/s23115317.
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The prices of different quality river crabs on the market can vary several times. Therefore, the internal quality identification and accurate sorting of crabs are particularly important for improving the economic benefits of the industry. Using existing sorting methods by labor and weight to meet the urgent needs of mechanization and intelligence in the crab breeding industry is difficult. Therefore, this paper proposes an improved BP neural network model based on a genetic algorithm, which can grade the crab quality. We comprehensively considered the four characteristics of crabs as the input variables of the model, namely gender, fatness, weight, and shell color of crabs, among which gender, fatness, and shell color were obtained by image processing technology, whereas weight is obtained using a load cell. First, mature machine vision technology is used to preprocess the images of the crab’s abdomen and back, and then feature information is extracted from the images. Next, genetic and backpropagation algorithms are combined to establish a quality grading model for crab, and data training is conducted on the model to obtain the optimal threshold and weight values. Analysis of experimental results reveals that the average classification accuracy reaches 92.7%, which proves that this method can achieve efficient and accurate classification and sorting of crabs, successfully addressing market demand.
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Dvoretsky, Alexander G., and Vladimir G. Dvoretsky. "Epibiotic Communities of Common Crab Species in the Coastal Barents Sea: Biodiversity and Infestation Patterns." Diversity 14, no. 1 (December 23, 2021): 6. http://dx.doi.org/10.3390/d14010006.
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Crabs are important ecosystem engineers in marine habitats worldwide. Based on long-term data, we analyzed the species composition and infestation indices of epibionts and symbionts colonizing the great spider crab, Hyas araneus, and two lithodid crabs—the northern stone crab, Lithodes maja, and the red king crab, Paralithodes camtschaticus—in the coastal zone of the Barents Sea. The epibiotic communities found on great spider crabs were closer to northern stone crabs (33%) compared to red king crabs (25%). The prevalence of mobile symbionts (amphipods, Ischyrocerus, and polychaetes, Harmothoe) and common epibionts, such as barnacles and hydrozoans, was low on great spider crabs and high on the body and in the gills of lithodid crabs. Epiphytes were abundant on great spider crabs but not present on both species of lithodid crabs. Egg symbionts found on H. araneus and P. camtschaticus do not affect their local populations. Differences in the fouling communities found on the three crab species are associated with host size range, surface properties of their carapaces, and behavior patterns.
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Redjeki, Sri, Ria Azizah Tri Nuraini, and Hadi Endrawati. "The Composition of Portunus pelagicus on the Fishing Ground Area of Danasari Waters, Pemalang Regency." Jurnal Kelautan Tropis 26, no. 2 (June 2, 2023): 377–86. http://dx.doi.org/10.14710/jkt.v26i2.18825.
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Blue swimming crab (Portunus pelagicus) is one of the most economically valuable marine products in Indonesia. The crabs productivity was generally still dependent on the population in the wild. Danasari Village is one of the main crab producers in Pemalang Regency. The daily fishing crab activities by fisherman direct an impact on decreasing of the natural crabs resources. This study determined the crabs composition in the fishing ground where usually spotted by the Danasari crab fisherman. This research obtained the information of a composition of female and male crabs, carapace width distribution, growth characterized, and the egg-berried female number. This study conducted on May to July 2022. The result in this research was a male crabs were dominated than females. The carapace width was generally amount 92-112 mm, while the growth characteristic of blue swimming crabs was negative allometric. The female crab gonad maturity was dominated by 2nd level gonad maturity, while the egg-berried female crabs were found 21 crabs totaled from 14 spot fishing grounds. Based on the carapace width distribution, there are a lot of blue swimming crab with undersized in shallow-depth fishing sites, while the crab size mostly above 100 mm already found at each spot in this research. The highest egg-berried female percentage was found at spot 7th and 13rd, where the female crabs at 7th spot were bigger carapace than at 13rd spot areas. These results indicated that crab resources in Danasari Waters and surround area were indicated potentially overfished, proven with undersized berried-female crabs. The management efforts will conduct an environmentally friendly fishing gear, regarding the policy of ministry regulating as to keep crab resources sustainable. In addition, scheduling rules for fishing activities can also be tested to be applied.
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Gabito, Porfirio P., and Christia Baltar. "Evaluating different diets on the growth performance of mud crab (Scylla serrata)." Can Tho University Journal of Science 15, no. 1 (March 30, 2023): 58–63. http://dx.doi.org/10.22144/ctu.jen.2023.007.
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The purpose of this study was to assess the potential of natural feeds for the sustainable grow-out aquaculture of mud crabs as an alternative to commercially available mud crab feeds. This study employed a completely randomized design that includes five feed treatments including trash fish, African land snail, horn snail, edible frog, and mud snail. There were three replicates for each treatment with three cages each located in a concrete tank with an area of 12m2. Each cage contained one lean crab. The crabs were fed twice a day, at 7 a.m. and 8 p.m. with an amount adjusted to 7% of the crab's body weight. After the first 21 days, all the crabs were harvested by draining out the tank water and the pincers of the crab were tied with a string to enable handling. The results showed that the highest growth performance in weight gain and condition factor was seen in African land snail feed with a feed conversion ratio of 1.38, indicating a high-quality feed. It also showed an impressive ROI of 96.8% which can be confirmed that this kind of feed might be a viable mud crab feed for both commercial scale and industry.
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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.
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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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Permadi, Sandi, and Sri Juwana. "Penetapan Kebutuhan Harian Pakan Ikan Rucah untuk Penggemukan Kepiting Bakau Scylla paramamosain di Keramba Jaring Dasar." Oseanologi dan Limnologi di Indonesia 1, no. 1 (May 31, 2016): 75. http://dx.doi.org/10.14203/oldi.2016.v1i1.26.
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<strong>Determination of Daily Requirement of Trash Fish Feed to Fatten The Mangrove Crab Scylla paramamosain in Bottom Net Cages.</strong> Mangrove crab fattening is part of the crab farming activities that attracts the interests of the farmers due to its relatively short period, i.e. 14–21 days per cycle. Trash fish is a natural feed for Mangrove crabs that is easily available at an affordable price. Scientific information on the daily requirement of trash fish feed to fatten the Mangrove crabs is still scarce. The accessable scientific information on the amount of daily feeding is still limited to the rearing of the crabs. Hence, the scientific study on the daily requirement of trash fish feed for crab fattening needs to be done. Probolinggo is one of the producing districts for Mangrove crabs and is a potential area for development of crab aquaculture. Therefore, Probolinggo was chosen as the site of this research. Crab samples utilized had a carapace width of 8–13 cm and a weight of 115–500 g. Crabs were reared in bottom net cages measuring 5 x 5 m2 with a density of 16 crabs/cage and the sex ratio of 1: 1. The study consisted of 4 treatments with 3 repetitions. The daily feeding percentages given were 10, 15, 20, and 25% of the body weight of the crabs. The parameters observed during the 13 days of experiment were growth, survival rate, and the percentage of already fatter crabs. The results showed that the daily feed ration of trash fish, as much as 10% dan 15% of the body weight of the crab, gave the best yield for crab fattening. The survival rate obtained was 70% of the initial density of 0.64 crabs/m2, with a total weight gain of 14% during the study. <br /><br />
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ELEGBEDE MANOU, Bernadin, Mahamadou Ilalou ATIKOU, Marc SOHOUNNON, Hervé LABITE, A. Yvette DEGUENON, A. Patrick EDORH, and Martin Pépin AINA. "Évaluation de bioaccumulation des métaux toxiques (pb, cu, mn) dans les espèces de crabes Callinectes amnicola et Cardisoma armatum consommés avec les légumes d’Abelmoschus esculentus dans la basse vallée de l’Ouémé (Benin, Afrique de l’ouest)." Journal of Applied Biosciences 154 (October 31, 2020): 15913–25. http://dx.doi.org/10.35759/jabs.154.8.
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Objectifs : Le présent travail porte sur l’évaluation de la bioaccumulation des métaux toxiques (Pb, Cu, Mn) des eaux, des sédiments, de deux espèces différentes de crabes Callinectes amnicola et Cardisoma armatum, et de légume Abelmoschus esculentus (famille des Malvaceae) et communément appelés Gombo consommés dans la basse vallée de l’Ouémé. Méthodologie et résultats : Pour ce faire, les teneurs de trois éléments traces métalliques (ETM) à savoir le manganèse (Mn), le cuivre (Cu) et le plomb (Pb) ont été recherchées dans les eaux, les sédiments de sable, le légume et les crabes à l'aide d'un spectrophotomètre d'absorption atomique à flamme dans 12 échantillons d’eau et sédiments puis dans 72 échantillons de crabes et 10 échantillons de légumes. Par la suite, une évaluation des risques sanitaires liés à la consommation de ces produits contaminés a été réalisée suivant une démarche standard simplifiée. Les résultats ont montré que tous les légumes Abelmoschus esculentus ont des teneurs en Mn et Cu dépassant la réglementation de l'OMS. Les résultats ont révélé également des concentrations en manganèse plus élevées dans les sédiments par rapport aux deux autres échantillons de crabe. Les crabes Cardisoma armatum accumulent plus le Cu et Pb que le crabe Callinectes amnicola. Les concentrations du plomb (Pb) et Mn sont en deçà des normes fixées par l'OMS. Par contre celles du cuivre et de manganèse dépassent largement la réglementation. Le facteur de bioconcentration (FBC) varie de 0,25 à 0,29 pour Mn, de 0,15 à 0,17 pour Cu et de 0,67 à 0,82 pour Pb. La présence de ces éléments traces métalliques dans les crabes, ne peut résulter que du phénomène de la biodisponibilité dans les sédiments. Conclusion et application des résultats : En conclusion, on peut retenir que l’évaluation de la bioaccumulation des métaux toxiques dans les aliments a montré que la consommation de crabes et légumes constitue un danger de santé publique pour la population de la basse vallée de l'Ouémé. Il serait indispensable d’attirer Elegbede Manou et al., J. Appl. Biosci. 2020 Évaluation de bioaccumulation des métaux toxiques dans les espèces de crabes consommés avec les légumes d’Abelmoschus esculentus dans la basse vallée de l’Ouémé, Benin. 15914 l’attention des populations afin qu'elles adoptent une ration alimentaire variée. Ces résultats devront être un outil d’aide à la prise de décision des autorités au niveau de la santé. La grande recommandation issue des résultats est de procéder à une surveillance sanitaire dans la basse vallée de l'Ouémé en ce qui concerne l’alimentation. Mots clés : Basse vallée de l’Ouémé (Bénin), bioaccumulation, métaux toxiques, gombo et crabes. Evaluation of the bioaccumulation of toxic metals (pb, cu, mn) in the consumed crab species Callinect amnicola and Cardisoma armatum with Abelmoschus esculentus vegetables in the low valley of Oueme (Benin, West Africa) ABSTRACT Objective : to evaluate the bioaccumulation of toxic metals (Pb, Cu, Mn) for two different species of crabs (i.e., Callinectes amnicola and Cardisoma armatum) and of vegetable Abelmoschus esculentus (family Malvaceae) commonly called Okra and consumed in the lower valley of the Ouémé. Methodology and results:To do this, the contents of three metallic trace elements (MTE) manganese (Mn), copper (Cu) and lead (Pb) were sought in water, sand sediment, vegetables and crabs by using a flame atomic absorption spectrophotometer in 12 water and sediment samples and then in 72 crab samples. To search for lead, manganese and copper, an assessment of the health risks associated with the consumption of these contaminated products was carried out using a simplified standard approach. The results showed that all the Abelmoschus esculentus vegetables had Mn and Cu contents exceeding the WHO regulations. The results also revealed higher Mn concentrations in the sediment compared to the other two crab samples. Cardisoma armatum crabs accumulate more Cu and Pb than the Callinectes amnicola crab. The concentrations of lead (Pb) and Mn were below the standards set by the WHO. On the other hand, those of copper and manganese largely exceeded the regulations. The bioconcentration factor (BCF) varied from 0.25 to 0.29 for Mn, from 0.15 to 0.17 for Cu and from 0.67 to 0.82 for Pb. The presence of these metallic trace elements in crabs, can only result from the phenomenon of bioavailability in sediments. Conclusion and application of results: In conclusion, it can be remembered that the assessment of the bioaccumulation of toxic metals in food has shown that the consumption of crabs and vegetables constitutes a public health hazard for the population of the lower valley of the Ouémé. It would be essential to attract the attention of the populations so that they adopt a varied food ration. These results should be used as a decision-making tool for health authorities. The main recommendation resulting from the results is to carry out health surveillance in the lower valley of the Ouémé with regard to food. Key words: Lower Ouéme Valley (Benin), bioaccumulation, toxic metals, okra and crab
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Hafidah, Maura Syafa, Eka Nurahemma Ning Asih, Ika Masruroh, and Moch Yusuf Kurniawan. "Karakteristik Biologi dan Kelimpahan Rajungan (Portunus pelagicus) di Sekitar Perairan Sumenep." Journal of Marine and Aquatic Sciences 9, no. 2 (March 11, 2024): 300. http://dx.doi.org/10.24843/jmas.2023.v09.i02.p15.
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The high demand for the crab export market has resulted in the crab commodity experiencing a decline and leading to exploitation. Prediction of crab stocks in Sumenep Regency is minimal due to a need for further information regarding crab data. This study aims to determine the biological characteristics of the blue swimming crab (Portunus pelagicus), limiting blue swimming crab (Portunus pelagicus), and water quality characteristics around Sumenep. Research methods is observation methods or directly contact fishermen. Data collection included blue swimming crab biology, including morphometric aspects, which consisted of measurements of carapace width, carapace length, weight, and level of gonadal maturity. Data collection for water quality parameters used the insitu method at each research location. The results of this study were variations in the morphometric characters of the crabs in the distribution of the carapace width of the male crabs found in class 121-138 mm, as many as 137 individuals, while the female crabs were found in class 121-138 mm as many as 136 individuals, the distribution of size class based on the length of the female crab in class 60 .42-68.42mm as many as 112 people. The size class distribution of male crabs was mainly found in the 51.42-59.42mm class of 96 individuals; the distribution of size classes based on the weight in male crabs in the 126-157 gram class was 65 individuals. The size class of female swimming crabs was found in the 158-189 gram class; as many as 67 individuals applied for crabs around Sumenep. Based on the crab data collection at the first location, Talango was 289 ind/700 cm2, the second location was Tanjung Saronggi, 65 and/700 cm2, and in the third location, Gili Genting, there was as much as 104 ind/700 cm2. The waters of Tanjung Saronggi are a location that has more male crabs than female crabs. The air quality characteristics around Sumenep waters are categorized as optimal for blue swimming crab habitat.
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Achmad Mufidh Karomatullah, Aninditia Sabdaningsih, and Suradi Wijaya Saputra. "Stock Analysis of Kroyo Crab in Cirebon Waters, Gebang Mekar Village, Gebang District, Cirebon Regency." International Journal of Islamic Education, Research and Multiculturalism (IJIERM) 5, no. 3 (November 10, 2023): 844–62. http://dx.doi.org/10.47006/ijierm.v5i3.273.
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The development of crabs in Cirebon Regency is one of the important indicators in increasing fisheries production, the increase is based on the high market demand for crab commodities, especially kroyo crabs, causing an impact on the crab population. This research was carried out from February 2022 to March 2023 in 3 sub-districts, namely Suranenggala, Mundu and Gebang. This study aims to determine the stock of kroyo crabs which include carapace width and weight, growth, condition factors, mortality, and exploitation rate. The method used is direct observation of special fishermen catching kroyo crabs. The key crabs measured during the study amounted to 360 individuals with a carapace width range of male crabs of 27-44 mm and female crabs of 28-51 mm, with a frequency distribution of 8 class intervals from December 2022 to February 2023. Tools used to analyze stock conditions using the help of FISAT II and Microsoft Excel software. The first size results were caught in males (L50%=34,18mm) with more than half the asymptotic length (½L∞=23,75mm), while in females (L50%=41,08mm) greater than half the asymptotic length (½L∞=25,75mm). The carapace-weight width relationship of the male crab is W = 1,227L0,510 and the female crab W = 0,371L0,896. Conditions factors in male crabs (1,007) and females (1,008) have the same level of mon-decency. Growth equation of Von Bertalanffy male crab Lt=47,25[1- e(-0,79(t+0,179))] and female crabs Lt=51,45[1- e(-0,99(t+0,138))], So it can be stated that the growth of female crabs is faster than that of male crabs. In male crabs, the Total Mortality Rate (Z) was obtained at 2.99 per year, natural mortality (M) of 1.39 per year, and arrest mortality (F) of 1.60 per year. While in female crabs Z = 2.44 per year, M = 1.57 per year, F = 1.60 per year. The exploitation rate (E) of male crabs was obtained at 0.54 per year and females at 0.35 which means that the capture of Charybdis anisodon waters is still a tendency of underfishing. The pattern of adding new male crabs in Cirebon waters has two peaks, namely in April and August, with female crabs in July. Based on the results of this study, it can be concluded that the stock condition in Cirebon waters is still in the category of suitable for fishing for fishermen.
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Redjeki, Sri, Muhammad Zainuri, Ita Widowati, Ambariyanto Ambariyanto, Rudhi Pribadi, and Michael Abbey. "Distribution and Size of Crab (Portunus pelagicus) in Betahwalang Waters, Demak, Central JavaSex Ratio, Size Distribution and Length-Weight Relationship of Portunus pelagicus Linnaeus, 1758 (Malacostraca : Portunidae) in Betahwalang, Demak, Central Java." Jurnal Kelautan Tropis 24, no. 1 (March 6, 2021): 133–40. http://dx.doi.org/10.14710/jkt.v24i1.10467.
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Blue Swimming Crab (P. pelagicus, Linnaeus, 1758) is the main fisheries product from Betahwalang peoples. Fishing activity of Blue Swimming Crab by the fisherman almost every day in Betahwalang waters. Distribution and body size data of Blue Swimming Crab can be used for sustain management reference. The purpose of this study was to determine distribution pattern and body size of Blue Swimming Crab, started from July to November 2018 in Betahwalang waters, Demak. The data analyze consist of sex ratio, carapace width distribution and relationship between carapace width and body weight. 11790 samples Blue Swimming crab from Betahwalang waters consist of 7070 female crabs and 4720 male crabs. The result showed that sex-ratio between male and female crabs are balanced (1.0:1.37), with the most female crabs found at July and August. Body size distribution of male and female crabs are dominated in class 103-111 mm carapace width. Male and female crabs have a positive allometric on growth parameters, that means growth of the body weight is faster than carapace width. The result showed that Blue Swimming Crab in Betahwalang waters are support for sustainable fisheries.
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Wong, RJ, MS Roy, and JEK Byrnes. "Sediment selection: range-expanding fiddler crabs are better burrowers than their historic-range counterparts." Marine Ecology Progress Series 674 (September 16, 2021): 163–71. http://dx.doi.org/10.3354/meps13811.
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Climate change plays a large role in driving species range shifts; however, the physical characteristics of an environment can also influence and alter species distributions. In New England salt marshes, the mud fiddler crab Minuca pugnax is expanding its range north of Cape Cod, MA, into the Gulf of Maine (GoM) due to warming waters. The burrowing lifestyle of M. pugnax means sediment compaction in salt marshes may influence the ability of crabs to dig, with more compact soils being resistant to burrowing. Previous studies indicate that salt marshes along the GoM have a higher sediment compaction relative to marshes south of Cape Cod. Physical characteristics of this habitat may be influencing the burrowing performance of M. pugnax and therefore the continuation of their northward range expansion into the GoM. We conducted a controlled laboratory experiment to determine if compaction affects the burrowing activity of M. pugnax in historical and range-expanded populations. We manipulated sediment compaction in standardized lab assays and measured crab burrowing performance with individuals collected from Nantucket (NAN, i.e. historical range) and the Plum Island Estuary (PIE, i.e. expanded range). We determined compaction negatively affected burrowing ability in crabs from both sites; however, crabs from PIE have a higher probability of burrowing in higher sediment compactions than NAN crabs. In addition, PIE crabs were more likely to burrow overall. We conclude that site level differences in compaction are likely altering burrowing behavior in the crab’s expanded-range territory by way of local adaptation or phenotypic plasticity.
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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.
Full textAbstract:
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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Redjeki, Sri, Muhammad Zainuri, Ita Widowati, Abdul Ghofar, Elsa Lusia Agus, Mustagpirin Mustagpirin, and Panji Ayodya. "Biology Reproduction and Dynamic of Gonads Maturity Blue Swimming Crabs (Portunus pelagicus) in Betahwalang Waters, Demak." Jurnal Kelautan Tropis 23, no. 3 (November 17, 2020): 357–61. http://dx.doi.org/10.14710/jkt.v23i3.8977.
Full textAbstract:
The waters of Betahwalang, Demak has quite potential fisheries resources. For the sustainability of crab resources, active management is necessary applied. Information on biology reproduction of crabs is required. The purpose of this research was to determine the biological aspects of sex ratio and the dynamics of the gonadal maturity level. This research was conducted on September-November 2018 in Betahwalang Waters. The method used in this study is a descriptive research method. Data were collected by determining gender, weight and width of the carapace, the level of gonadal maturity. The results from observations of crab landed with a total of 6,292 crabs showed a percentage of 37.30% males and 62.70% females with sex ratios in September (1: 1.70), October, (1: 1.46), and November (1: 1.98). The observation of gonadal maturity level in September (Level I 162 crabs, Level II 1425 crabs, Level III 607 crabs) in October (Level I 130 crabs, Level II 832 crabs, Level III 207 crabs), and in November (Level I 46 crabs, Level II 753 crabs, Level III 195 crabs). The results show that the average crab catch on Betahwalang waters is dominated by the gonad II maturity level reaching (> 70%) of the total female caught. The results of the gonad maturity level are influenced by weather and season factors where the trend of the gonad maturity level will drop in the rainy season or in November.
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Layne, John, Michael Land, and Jochen Zeil. "Fiddler Crabs Use the Visual Horizon to Distinguish Predators from Conspecifics: A Review of the Evidence." Journal of the Marine Biological Association of the United Kingdom 77, no. 1 (February 1997): 43–54. http://dx.doi.org/10.1017/s0025315400033774.
Full textAbstract:
Male fiddler crabs, Uca pugilator (Crustacea: Decapoda), respond to conspecifics by claw waving, and to predators by freezing or escape. In field experiments it was found that this distinction was not made on the basis of angular size and speed, nor was shape important. The remaining possibilities were either the absolute size of the stimulus, determined from angular size and distance, or the position of the stimulus relative to the horizon. To distinguish between these, a crab was placed in a glass dish, and moved black stimuli on a white background, at a distance of 22 cm. Stimuli below the crab's horizon hardly ever evoked escape. However, identical stimuli partially or wholly above the crab's horizon produced escape responses whose frequency varied with the angular size of the stimulus. Halving the distance of the stimulus showed that it was angular and not absolute size that determines escape frequency; and experiments with a tilted horizon showed that it is the position of the stimulus relative to the eye equator that is important, rather than the geographical horizon itself. It has been concluded that crabs categorize stimuli as dangerous or otherwise by their position relative to the crabs’ visual horizon.
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Kobayashi, Chisato, and Makoto Kato. "Sex-biased ectosymbiosis of a unique cirripede, Octolamis unguisiformis sp. nov., that resembles the chelipeds of its host crab, Macrophthalmus milloti." Journal of the Marine Biological Association of the United Kingdom 83, no. 5 (September 19, 2003): 925–30. http://dx.doi.org/10.1017/s0025315403008075h.
Full textAbstract:
An ecologically unique cirripede, Octolasmis unguisiformis sp. nov. (Cirripedeia: Thoracica: Poecilasmatidae), was found to be ectosymbiotic with an ocypodid crab, Macrophthalmus milloti, on tidal flats of the Amami Islands, the Ryukyu Archipelago, Japan. The cirripedes were attached to the ventral side of the crab carapace, around the bases of the first and second ambulatory legs. The cirripedes resemble the chelipeds of male host crabs. Adult cirripedes were found only on female crabs, whereas juvenile cirripedes were present on crabs of both sexes, suggesting that the survival rate of the cirripedes on female crabs was higher than that of those on male crabs. The cheliped-like appearance and female-biased distribution of the cirripedes are discussed from the standpoint of mutualism between the crab and the epizoic cirripede.
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Utomo, R. P., P. Maulana, and M. W. Taqiyuddin. "Seasonal comparison of catch abundance and size of blue swimming crab (Portunus pelagicus) in Rembang, Central Java." IOP Conference Series: Earth and Environmental Science 1251, no. 1 (October 1, 2023): 012048. http://dx.doi.org/10.1088/1755-1315/1251/1/012048.
Full textAbstract:
Abstract Considering the blue swimming crab (Portunus pelagicus) was exported as pasteurized crab meat, the quality of fresh meat (stock and size) could have been influenced by the season and needed to be considered. This study aimed to analyse the effect of the season on the crab’s abundance and size in Rembang Water, Central Java. The study period includes four seasons, namely west monsoon, first transition, east monsoon, and second transition from July 2021 to June 2022. The crab samples from the fishermen were analysed in term of the fishing trips, weight, and carapace width at the fishing ground location. Descriptive statistics and univariate one-way ANOVA was used to analyze the data. The average abundance, weight, and size of crabs caught in Rembang waters during the year were 1,8 kilograms per trip a day (one-day fishing). The abundance of crabs in the west monsoons was greater than in the east monsoons. The pattern of crabs caught was higher at the beginning of the west monsoon (December–January), then it decreased in February until the start of the first transition (March), then gradually increased in April before decreasing again in June until the end of the second transition (October). The ANOVA test showed that the size of crabs in every season had significant differences. It was clearly shown on the boxplot that the catch in the west monsoon and the first transition was smaller than the east monsoon and second transition. These results can provide insightful information for fishers, managers, and policy makers as a basis for developing sustainable fisheries management.
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Mikhailova, O. G., and P. Yu Ivanov. "Potential impact of harvesting on Tanner crab (Chionoecetes bairdi) on state of its commercial stock off the coast of Kamchatka." Izvestiya TINRO 201, no. 1 (April 4, 2021): 112–23. http://dx.doi.org/10.26428/1606-9919-2021-201-112-123.
Full textAbstract:
Potential impact of landing on the stock and biological state of Tanner crab is analyzed for two fishery districts at Kamchatka in 2013-2020. In the Kamchatka-Kuril fishery subzone, the number of commercial males without limbs and with old shell increased in catches that may be associated with active operations of alive-crab vessels in 2015-2017. In the Petropavlovsk-Commander fishery subzone, cases of injured Tanner crabs catch became frequent after resumption of the crab harvesting in 2017, as well as the cases of commercial crabs with old shell, that also could be explained by operations of alive-crab vessels. The operations of such vessels are distinguished by strict sorting of caught crabs with removing the individuals of lower quality. As the result, the crabs without limbs and commercial males at late stages before molting were accumulated in the areas of sorting. The problem can be solved by measures for total registration (weighting) of catch before the start of sorting, concerning to all crabs with commercial size landed aboard. To avoid degradation of the Tanner crab population, development of catch processing aboard fishing vessels is recommended, with transportation of frozen products instead of live crabs.
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Bleile, Nadine, and David W. Thieltges. "Prey preferences of invasive (Hemigrapsus sanguineus, H. takanoi) and native (Carcinus maenas) intertidal crabs in the European Wadden Sea." Journal of the Marine Biological Association of the United Kingdom 101, no. 5 (August 2021): 811–17. http://dx.doi.org/10.1017/s0025315421000655.
Full textAbstract:
AbstractInvasive predators can have wide-ranging effects on invaded ecosystems and identifying the prey spectra and preferences of invaders are important steps in assessing their potential impacts on native biota. In this study, we investigated prey preferences of two invasive crab species (Hemigrapsus sanguineus and Hemigrapsus takanoi) that recently invaded Europe's shores and compared them with preferences of native shore crabs (Carcinus maenas) of similar size. In laboratory experiments, all three crab species preferred animal over algal prey. In general, sessile mussels (Mytilus edulis) were preferred over motile amphipods (Gammarus locusta) by all three crab species but amphipod predation was lower in the invasive compared with the native crabs. For the two invasive crab species, this pattern was the same in treatments where prey was offered separately (no-choice treatments) or simultaneously (choice treatments), while for the native crabs, mussel preference disappeared in choice treatments. The general preference of mussels by all three crab species suggests that local invasions of crabs most likely lead to increased competition among crabs. In addition, given that local densities of invasive crabs are often much higher than those of native crabs, predation pressure on native mussels can be expected to strongly increase at invaded sites. In contrast, local predation pressure on amphipods may be less affected by the crab invasions. Further field studies are needed to establish the magnitude of competition and predation pressure exerted by the invaders under natural conditions.
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Bleile, Nadine, and David W. Thieltges. "Prey preferences of invasive (Hemigrapsus sanguineus, H. takanoi) and native (Carcinus maenas) intertidal crabs in the European Wadden Sea." Journal of the Marine Biological Association of the United Kingdom 101, no. 5 (August 2021): 811–17. http://dx.doi.org/10.1017/s0025315421000655.
Full textAbstract:
AbstractInvasive predators can have wide-ranging effects on invaded ecosystems and identifying the prey spectra and preferences of invaders are important steps in assessing their potential impacts on native biota. In this study, we investigated prey preferences of two invasive crab species (Hemigrapsus sanguineus and Hemigrapsus takanoi) that recently invaded Europe's shores and compared them with preferences of native shore crabs (Carcinus maenas) of similar size. In laboratory experiments, all three crab species preferred animal over algal prey. In general, sessile mussels (Mytilus edulis) were preferred over motile amphipods (Gammarus locusta) by all three crab species but amphipod predation was lower in the invasive compared with the native crabs. For the two invasive crab species, this pattern was the same in treatments where prey was offered separately (no-choice treatments) or simultaneously (choice treatments), while for the native crabs, mussel preference disappeared in choice treatments. The general preference of mussels by all three crab species suggests that local invasions of crabs most likely lead to increased competition among crabs. In addition, given that local densities of invasive crabs are often much higher than those of native crabs, predation pressure on native mussels can be expected to strongly increase at invaded sites. In contrast, local predation pressure on amphipods may be less affected by the crab invasions. Further field studies are needed to establish the magnitude of competition and predation pressure exerted by the invaders under natural conditions.
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Triana, Aprilya, Susiana Susiana, Wahyu Muzammil, and Dedy Kurniawan. "Morphometric characteristics of red crab (Thalamita spinimana) in Dompak Tanjungpinang Waters, Riau Islands." Akuatikisle: Jurnal Akuakultur, Pesisir dan Pulau-Pulau Kecil 6, no. 1 (May 18, 2022): 75–78. http://dx.doi.org/10.29239/j.akuatikisle.6.1.75-78.
Full textAbstract:
The morphometric characteristics of the red crab (Thalamita spinimana) have not been widely studied. This research was conducted from March to May 2021 in the waters of Dompak Tanjungpinang, Riau Islands. Each sample obtained directly measured the morphometric part using a caliper or calipers with an accuracy of 0.05 mm and the crab body weight was also weighed using a digital scale with an accuracy of 0.1 g. The samples obtained during the study were 119 crabs, of which 84 female red crabs and 35 male red crabs. The carapace width range for female crabs is 55.40 – 88.32 mm, while in male crabs the carapace width range is 16.35 and 34 individuals 68.96 – 90.94 mm. The weight of female red crabs is in the range of 50.0 – 103.6 g, while the weight of male crabs is in the range of 49.0 – 142.8 g.
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Homberger, Lena, Jiawu Xu, Dirk Brandis, Tin-Yam Chan, Heleen Keirsebelik, Monika Normant-Saremba, Jonas Schoelynck, Ka Hou Chu, and Christine Ewers-Saucedo. "Genetic and morphological evidence indicates the persistence of Japanese mitten crab mitochondrial DNA in Europe for over 20 years and its introgression into Chinese mitten crabs." NeoBiota 73 (May 25, 2022): 137–52. http://dx.doi.org/10.3897/neobiota.73.72566.
Full textAbstract:
Cryptic biological invasions are largely unrecognised, leading to an underestimation of the number of invading taxa and their potential impacts. The Chinese mitten crab, Eriocheir sinensis, is a highly invasive species with serious economic and ecological impacts in Europe. Recently, mitochondrial DNA (mtDNA) of the Japanese mitten crab, E. japonica, has been discovered in populations from The Netherlands, Poland and Germany, but the taxonomic status and time of introduction of specimens carrying this mtDNA are uncertain. To this end, we investigated the morphology and variation of the mitochondrial cytochrome c oxidase subunit I (COI) gene of mitten crabs collected in central-western Europe between 1998 and 2020. Mitten crabs from Belgium harboured a Japanese mitten crab COI haplotype in 33% to 65% of individuals, even in our earliest samples from 1998. All other studied populations carried only Chinese mitten crab COI haplotypes. Morphologically, many of the juvenile Belgian mitten crabs showed intermediate traits between the two species, while all investigated adult mitten crabs, regardless of their mitochondrial haplotype or country of origin, were morphologically assigned to E. sinensis. This intermediate morphology of the juveniles and genetic-morphological discrepancy of adults suggests that Japanese mitten crabs introgressed with Chinese mitten crabs, which could have happened both before and after the introduction of mitten crabs to Europe. A specific Chinese mitten crab COI haplotype, found in Belgium, was previously only known from Vladivostok (Russia), where Chinese and Japanese mitten crab hybrids naturally occur. This Far East region is, therefore, a plausible source for at least part of the mitten crab mitochondrial diversity in Belgium.
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Risa, Nurul Eka Wijayanti, Aam Azatil Isma, and Andi Panca Wahyuni. "PELATIHAN PENGGUNAAN CRAB BOX PADA PEMBESARAN KEPITING BAKAU DESA KAJUARA KABUPATEN BONE." MESTAKA: Jurnal Pengabdian Kepada Masyarakat 2, no. 5 (October 8, 2023): 222–26. http://dx.doi.org/10.58184/mestaka.v2i5.144.
Full textAbstract:
The method of cultivating mud crabs in Kajuara Village is still carried out traditionally and uses natural food, thus affecting the production of crabs which are not uniform in terms of size and weight. Apart from that, there is still a lack of partner knowledge regarding the behavior and habits of mud crabs as well as appropriate methods for cultivating mud crabs. The aim of this service is to increase the knowledge and skills of cultivators in cultivating mud crabs using crab boxes. The stages of implementing service activities include: 1) Survey and interview stage, 2) preparation stage, 3) implementation stage and 4) evaluation stage. Based on the achievements of the service activities, participants have knowledge and skills in the mud crab cultivation method using a crab box.
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Takeda, Satoshi. "Burrowing-site selection by the soldier crab Mictyris guinotae Davie, Shih & Chan, 2010 (Decapoda: Brachyura: Mictyridae)." Journal of Crustacean Biology 40, no. 2 (February 27, 2020): 147–51. http://dx.doi.org/10.1093/jcbiol/ruz097.
Full textAbstract:
Abstract The soldier crab Mictyris guinotae Davie, Shih & Chan, 2010 inhabiting sandy tidal flats in the Ryukyu Is., Japan, are deposit feeders in two regions: its upper habitat where it burrows and the shoreline. The crabs usually migrate between these two regions during the period of emergence at the daytime and night-time low tide. The aim of this study was to determine which kind of sediments are chosen by the crabs when burrowing. Experiments designed to investigate burrowing-site selection revealed that the crabs preferably burrowed in sediment that had been conditioned through feeding by conspecific crabs, but not in sediment that had been conditioned by conspecific crabs walking on its surface. Moreover, the crabs never showed any preference for burrowing in sediment that had been conditioned through feeding by the competitor fiddler crab Austruca perplexa (H. Milne Edwards, 1852); both soldier (prey) and fiddler (predator) crabs sympatrically inhabit the tidal flat, but segregate their habitats with a transition area. These results suggest that chemical cues in sediment conditioned through feeding by conspecific soldier crabs affect where crabs burrow.
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Davis, Jana LD, Alicia C. Young-Williams, Anson H. Hines, and Yonathan Zohar. "Assessing the potential for stock enhancement in the case of the Chesapeake Bay blue crab (Callinectes sapidus)." Canadian Journal of Fisheries and Aquatic Sciences 62, no. 1 (January 1, 2005): 109–22. http://dx.doi.org/10.1139/f04-150.
Full textAbstract:
In certain cases of severely depleted fishery stocks, combining stock enhancement with traditional management techniques may be a useful way of returning stocks to an exploitable size. The Chesapeake Bay stock of blue crabs (Callinectes sapidus) has declined over the past decade and appears to be recruitment-limited, making it an appropriate candidate for enhancement efforts. This study serves as a first step in determining whether large-scale enhancement of blue crab stocks is feasible. Four hatchery-raised cohorts of 4000 10 000 (25 000 in total) juvenile (630 mm carapace width, 5870 days old) crabs were released in upper Chesapeake Bay coves. Sixty days after release, these crabs constituted 22%79% of all crabs in the hatchery-crab size range (corresponding to an enhancement level of 28%366%). Crabs released earlier in the summer reached maturity at the age of 6 months, younger than their wild counterparts. Estimated survivorship to maturity was 16%20% for early-released crabs and 515% for late-released crabs. Late-released crabs, like wild crabs, had to overwinter before becoming mature. Our study suggests ways to improve success of hatchery-raised individuals that can be broadly applied across taxa. The results also contribute specifically to determining whether large-scale stock enhancement is possible in the case of the Chesapeake Bay blue crab.
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Mawusi Obubuafo, Joyce Mamle, Grace Denny Doku, Mawutor K. Glover, and Margaret Aba Sam Hagan. "Observing the Impact of Confinement on the Rearing of Land Crabs." Journal of Food Industry 4, no. 1 (June 30, 2020): 59. http://dx.doi.org/10.5296/jfi.v4i1.17286.
Full textAbstract:
The study observed the impact of confinement on the rearing of land crabs in an attempt to produce crabs that can be consumed without having to worry about their unwholesomeness, traceability and also the possibility of producing crabs all year round.Two species of the land crabs were observed for five months: 35 Rainbow land crabs, obtained from Ada, a suburb of the Greater Accra Region of Ghana and 20 Blue land crabs obtained from Sokode, a suburb of the Volta Region of Ghana. the study investigated the 55 land crabs by observing their coexistence, feeding and reproduction in confinement. Dealers in land crabs and other resource persons who had some experience with land crabs where interviewed. At the beginning of the study, the average weight of a male rainbow land crab was 3.3 pounds and that of a female was 3.0 pounds. However, at the end of the study the average weight recorded for the male Rainbow land crab was 5.7poundsand that of the female was 5.4pounds. The number of rainbow land crabs that died during the cause of the study was 7 and 12 escaped resulting in 16 of them remaining by the end of the study. Six of the crabs lost their appendages, one female moulted, 4 female crabs produced eggs and spawned. The only female Blue land crab that survived produced eggs in confinement but later died after three weeks from the commencement of the study. Results of the study showed that the Rainbow land crabs are hardier as compared to the Blue land crabs and thus, the best specie that can be reared in confinement. The Rainbow land crabs can be reared in confinement for a minimum period of five months if the confined area is darkened and hideout accessories provided. The crabs can be fed on a range of diets, from fish, vegetables to leftovers from the kitchen. However, the crabs seem to prefer sugar cane, palm fronds and fruits. The female Rainbow land crabs are capable of spawning in confinement when provided with the right conditions and environment.
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SENKEL, I. ARTHUR, BEVERLY JOLBITADO, ERIN M. BUTLER, and THOMAS E. RIPPEN. "A Comparison of Different Processing Methods for Picked Blue Crab (Callinectes sapidus)." Journal of Food Protection 68, no. 2 (February 1, 2005): 360–65. http://dx.doi.org/10.4315/0362-028x-68.2.360.
Full textAbstract:
Five methods for producing picked crab meat from cooked blue crab (Callinectes sapidus) were evaluated for internal food temperatures and bacterial numbers at various process points. Whole shell-on crabs, crab cores (“backed” crabs with carapace removed), and crab meat samples were analyzed for standard plate count, total coliforms, fecal coliforms, Escherichia coli, and Staphylococcus aureus. For three of the processes, crabs were backed and washed a substantial time before picking; one of the processes used an ice slush dip to cool cooked crabs. Except for a single crab sample, bacteria were not isolated from crab and core samples. Standard plate count, E. coli, and S. aureus in crab meat samples from the different processes were statistically the same. Bacterial numbers in fresh picked crab meat samples exposed to an ambient temperature of 20 to 21.1°C for 1.5 and 3.5 h and stored at 1°C for 3 to 4 days and 7 to 8 days did not significantly differ (P < 0.05).
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Romadhon, Achmad, Eva Prasetiyono, and Arthur Muhammad Farhaby. "Laju Pertumbuhan Dan Kecepatan Molting Kepiting Bakau (Scylla serrata) Dengan Pemberian Ekstrak Daun Pakis Hutan (Diplazium caudatum)." Journal of Tropical Marine Science 5, no. 1 (January 10, 2022): 9–18. http://dx.doi.org/10.33019/jour.trop.mar.sci.v5i1.2312.
Full textAbstract:
The cultivation of mud crabs is growing to get crabs in the soft shell condition. But most of the soft shell crab's farmers do not experience sustainable business. The main obstacle is the length of the maintenance period and moulting time does not unison thereby causing the feed and operating costs to be high. The research aimed to examine the effect of injection with forest fern leaf extract on growth rate and moulting speed of mangrove crabs (Scylla serrata) and determine the best dose in the process of injecting forest Fern Leaf extract for mangrove crab (Scylla serrata). Treatment of mangrove crab (Scylla serrata) weight ± 100 g with dose: P1 (NaCL 0.9%) P2 (50 mg.L-1) P3 (75 mg.L-1) P4 (100 mg.L-1) P5 (125 mg.L-1) 5 crabs each are cared for 30 days, The research was conducted using a single complete random draft (RAL), the results of various analyses showed the significant forest fern leaf extract against the growth of absolute weights, the rate of Specific growth, and relative growth, but no noticeable effect for molting speed and absolute length growth. The results of this research showed that a dose of 125 mg.L-1produces the highest value with result for moulting speed of 0.50 ± 0.57, length absolute growth of 0.37 ± 0.1 weighted absolute growth of 20 ± 5,74, specific growth rate of 0.54 ± 0.13, and relative growth of 0.64 ± 0.18.
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Nguyen, Anh T., Luong C. Vu, and Hoa P. Nguyen. "The leaf litter consumption and occurrence of sesarmid crab Parasesarma plicatum (Latreille, 1803) on habitats in Can Gio mangrove forest." Journal of Agriculture and Development 23, no. 1 (February 26, 2024): 51–63. http://dx.doi.org/10.52997/jad.1.05.2024.
Full textAbstract:
The experiment was conducted from September to December, 2022 to identify the consumption of Parasesarma plicatum (Latreille, 1803) on different Rhizophora apiculata leaf litter conditions (senescent: yellowish in color, decomposition: red brown and black brown color) in a 72-h experiment with 2 crab sizes. The experiment was designed with 6 treatments and 5 replicates. Each treatment used 5 crabs which were provided with 1 type of leaves as their food. The treatments included T1: 5 bigger size crab + yellowish leaf, T2: 5 bigger size crab + reddish brown leaf, T3: 5 bigger size crab + black brown leaf, T4: 5 small crabs + yellowish leaf, T5: 5 small crabs + reddish brown leaf, and T6: 5 small crabs + black brown leaf. The results showed that the consumption of black brown leaf litter of the bigger size crab was the highest in weight and significantly different from all other treatments. It also showed that Parasesarma plicatum did not like to eat yellowish leaf litter in all treatments. In addition, there was not a statistically significant difference in leaf litter consumption among smaller crab groups. The research on the occurrence of sesarmid crabs in Can Gio mangrove forest identified two suitable habitats for sesarmid crabs according to tidal elevation, mangrove type and environmental factors. The main factors affecting the occurrence of sesarmid crabs in the habitats were the coverage of shading trees and the mangrove type (Rhizophora apiculata, Ceriops decandra, Avicennia officinalis, Avicennia marina and Lumnitzera racemosa). Thus, Parasesarma plicatum could play an important role in the detrital food web in Can Gio mangrove forest.
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Syaravicena, Dwi, Sri Jayanthi, Aini Ramadila, Suci Nurlida Sapitri, Devi Anisa, and Viska Anisa Sabrini. "Identification of Food Types of Ghost Crabs (Ocypode kuhlii L.) in The Intertidal Zone of Peudawa Beach, East Aceh." Jurnal Biologi Tropis 23, no. 2 (December 19, 2023): 339–44. http://dx.doi.org/10.29303/jbt.v23i2.6166.
Full textAbstract:
Ghost crabs are one of the arthropod animals that live in coastal ecosystems and are one of the key species that have a very important role in maintaining ecological balance. Here the author refers to the abundance of ghost crabs and the types of food eaten by ghost crabs, this is because there are still many who do not know about the types of ghost crab hands and the abundance of ghost crab hands and the abundance of ghost crabs on an east aceh beach. The type of research used was quantitative research with a random sampling method which was carried out on November 25 2023. From the results of this crab density research, there were 100 individuals with a translation size of 254M and a density index of 1,96 D at 40 54’’ 9’ N 970 51’’ 2’ T. Aceh Regency Timur, the types of food for ghost crabs are Zooplankton, Phytoplankton and Bacterioplankton. The conclusion of this research is that the existence of this crab population is greatly influenced by the condition of the beach which is its habitat. Natural beaches usually find many ghost crabs because the food chain process is still maintained.
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Miller, R. J., and J. T. Addison. "Trapping interactions of crabs and American lobster in laboratory tanks." Canadian Journal of Fisheries and Aquatic Sciences 52, no. 2 (February 1, 1995): 315–24. http://dx.doi.org/10.1139/f95-032.
Full textAbstract:
The relationship between trap catches of decapods and their abundance is not well established. Because it is difficult to manipulate density in the field, laboratory tanks were used to examine 10 hypotheses about the intra- and interspecific interactions of rock crab (Cancer irroratus), green crab (Carcinus maenas), and American lobster (Homarus americanus). The proportion of rock crabs captured did not differ among high, medium, and low densities, but the proportion captured was reduced at high densities for both green crabs and lobsters. Additional experiments demonstrated that large green and rock crabs in the tanks reduced the catch of small green and rock crabs and that the presence of lobsters reduced the catch of both crab species considerably. However, small rock crabs did not reduce the catch of large rock crabs, and neither green nor rock crabs reduced the catch of each other. Reductions in the catch of a target species caused by interactions in the field can perhaps be lessened by removing the catch from the trap at intervals of less than 24 h. Then the catches would be summed over 24 h for an index of abundance.
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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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Adam, Hasmawati, and Husniati. "Distribution of Blue Swim Crab (Portunus pelagicus) Catching Areas Using Foldable Traps in the Coastal Waters of Barru Regency, Indonesia." Asian Journal of Fisheries and Aquatic Research 25, no. 6 (December 5, 2023): 20–27. http://dx.doi.org/10.9734/ajfar/2023/v25i6713.
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The utilization of blue swim crab resources poses a significant challenge that requires appropriate solutions, thus necessitating effective resource management. Uncontrolled fishing conditions can lead to economic overfishing if proper management is not implemented. Moreover, fishermen compete to increase their fishing efforts, leading to the need for capturing in more distant areas. Therefore, rehabilitation and management actions need to be promptly executed. This study aims to analyze blue swim crab catching areas based on distance from the coast, crab weight, carapace width, size of adult crabs, and the size of crabs eligible for capture in the coastal waters of Barru Regency. The research was conducted over 8 months, from May to December 2022, in the blue swim crab fishing grounds in the waters of Barru Regency, South Sulawesi Province. Data Was collected through a combination of survey and observation methods. The collected data were descriptively analyzed SPSS and Microsoft Excel programs. The results indicate that: (1) Constituted 51.8% of the captured individuals, and females constituted the remaining 48.2%; (2) The average weight and carapace width of these crabs fluctuated based on the distance and depth of the fishing areas; (3) A higher number of adult-sized crabs were caught in the crab catching areas at a distance of 3-5 nautical miles from the coast; (4) The percentage of adult crabs was larger compared to crabs eligible for capture, indicating symptoms of overfishing; (5) All the individuals were of mature size. Specifically, 88.9% for male crabs and 94.3% for female crabs. The criteria used to determine eligibility for capture were carapace width above 11 cm.
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Maryani, Leni, Dietriech Geoffrey Bengen, and I. Wayan Nurjaya. "Distribution and Growth Patterns of Crab (P. pelagicus) Based on Environmental Characteristics in Candi Waters, Pamekasan Regency, East Java Province." Jurnal Kelautan Tropis 26, no. 2 (May 10, 2023): 340–48. http://dx.doi.org/10.14710/jkt.v26i2.17322.
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Blue swimming crab (BSC) is a fishery commodity with high economic value and great demand in domestic and foreign markets. P. pelagicus swimming crabs are commonly found in Indonesian sea waters, one of the largest contributors to the country's foreign exchange after shrimp and tuna. The high demand for blue crab resources will trigger an increase in fishing efforts. If this is done continuously, it is feared that it could endanger the population structure. Moreover, disrupting the sustainability of blue swimming crab resources in the waters, this study examines the morphometric distribution and growth pattern of P. pelagicus crabs based on environmental characteristics in Candi waters, Pamekasaan Regency. Census sampling was carried out using the census method; the census method was carried out by taking all crab samples caught by fishermen. The results obtained found 33 individual crabs, which were divided into three classes, namely small (<10 cm), medium (>10 cm), and large (>12 cm) size classes. Male crabs dominated the research locations with wider straps than female crabs. The analysis results show that the width-weight relationship's b values are 1.47 (males) and 2.00 (females). In addition, male and female crabs have a positive allometric growth pattern. Blue swimming crabs are often found in habitats with a substrate of dusty mud, high salinity and organic matter.
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Barber, Julie S., and J. Stanley Cobb. "Injury in trapped Dungeness crabs (Cancer magister)." ICES Journal of Marine Science 64, no. 3 (March 19, 2007): 464–72. http://dx.doi.org/10.1093/icesjms/fsm021.
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Abstract Barber J. S., and Cobb, J. S. 2007. Injury in trapped Dungeness crabs (Cancer magister). – ICES Journal of Marine Science, 64: 464–472. Although traps are the most effective fishing equipment used to capture crabs they can also result in indirect damage to target species. We examined the effect of trap-soak time, crab density, and the legal to sublegal size ratio on injury rates to male Dungeness crabs, Cancer magister. Our field results show that injuries increase significantly with increased trap-soak time, and as a consequence of different size ratios (crabs in traps with a greater ratio of sublegal crabs had more injuries). The injury rate was independent of density. In a laboratory experiment, injured crabs were as capable as intact crabs of obtaining, defending, and consuming food. However, studies on other crab species indicate that injury reduces growth, delays reproduction, decreases mating success, and increases mortality. If the costs of injury are similar for Dungeness crabs, this could diminish the rate of recruitment into the fishery.
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Grisley, M. S., P. R. Boyle, G. J. Pierce, and L. N. Key. "Factors affecting prey handling in lesser octopus (Eledone cirrhosa) feeding on crabs (Carcinus maenas)." Journal of the Marine Biological Association of the United Kingdom 79, no. 6 (December 1999): 1085–90. http://dx.doi.org/10.1017/s0025315499001332.
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Octopuses (Eledone cirrhosa) feeding on crabs (Carcinus maenus) may penetrate the crab by a carapace borehole or puncture of the eye. In ad libitum feeding trials (632 crabs eaten), 31% of the predated crabs had a punctured eye, 57% had a borehole in the dorsal carapace. Eye puncture and boring occurred together in 6% of cases but 18% were neither punctured nor bored.Feeding trials in which size of prey and size of octopus were controlled showed that the incidence of boreholes was greatest (>70%) in small crabs (<50 mm carapace width). Incidence of eye puncture (10% in small crabs) rose to 25% in crabs of over 50 mm carapace width and to over 40% in the largest crabs used (65–80 mm carapace width).Large octopuses used eye puncture less frequently than small octopuses. Increasing the proportion of small crabs in the diet increased the subsequent incidence of carapace boring at all crab sizes. The results are discussed in relation to differences in prey handling efficiency at different prey sizes.
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Salas-Maldonado, Mauricio, Elaine Espino-Barr, Emigdio Marín-Enríquez, Alberto Bartoleño-Sánchez, and Leonardo Daniel Valdez-Carrazco. "Size selectivity and optimal soaking time of hoops and traps targeting the blue swimming crab Callinectes arcuatus in Cuyutlan Lagoon, Mexico." Revista de Biología Marina y Oceanografía 56, no. 1 (June 7, 2021): 42. http://dx.doi.org/10.22370/rbmo.2021.56.1.2797.
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The selectivity of two types of commercial fishing gear (crab hoop/traditional gear and rigid rectangular cage traps) targeting blue crabs (Callinectes arcuatus) in Cuyutlan Lagoon, Mexico, was assessed. The effect of soak time on crab catches versus the retention and escape rate of organisms was also evaluated. Results suggested that traps captured larger individuals than hoops. The carapace width of crabs was significantly different between the fishing gears used: 63.9% of crabs caught with hoops were < 95 mm (sizes ranged from 40 to 113 mm) and 40.7% of crabs caught with traps were < 95 mm (range: 49 to 120 mm). Results also showed that catch rates were high during the first two hours and decreased after the third hour. The crabs tended to escape after several hours of soak time. The study found that the traps captured larger crabs than the hoops, suggesting that traps are a suitable fishing gear for catching blue swimming crabs in Cuyutlan Lagoon.
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Niswar, Muhammad, Zahir Zainuddin, Yushinta Fujaya, and Zagita Marna Putra. "An Automated Feeding System for Soft Shell Crab." Indonesian Journal of Electrical Engineering and Computer Science 5, no. 3 (March 1, 2017): 564. http://dx.doi.org/10.11591/ijeecs.v5.i3.pp564-568.
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<p>Soft shell crab farming has been practiced in south-east Asian countries such as Indonesia. Soft shell crabs are harvested when they have just molted to prevent their shells from being hardened. An issue arises when feeding the crabs. Farmers need to feed the crabs 5% food of their body weight. However, farmers sometimes provide incorrect amounts of food to the crabs. If farmers feed the crab exceeding the required amounts of food, it causes food wastage and dirty water in the crabs’ cage. On the other hand, less amounts of food causes slow growth and molting of the crabs. In this study, we developed an automated feeding system for properly feeding of soft-shell crabs. The automated feeding system schedules the feeding time and controls the portion of food using a microcontroller. We also developed a web-based monitoring system to monitor and generate alert message to farmers to make sure that feeding process runs properly.</p>
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Rachmawati, Wanda, Gina Septiani, and Esti Handayani Hardi. "PENGARUH PENAMBAHAN FITOIMUN® KE DALAM PAKAN TERHADAP PERTUMBUHAN KEPITING BAKAU (Scylla serrata) YANG DIPELIHARA DI TAMBAK SILVOFISHERY DESA SALO PALAI KECAMATAN MUARA BADAK KABUPATEN KUTAI KARTANEGARA." Jurnal Akuakultur Rawa Indonesia 10, no. 2 (December 30, 2022): 212–25. http://dx.doi.org/10.36706/jari.v10i2.19268.
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Mangrove crab (Scylla serrata) is a crab that has high potential and is cultivated in mangrove areas, so that many people keep mangrove crabs. However, there are still many obstacles, including slow growth. The purpose of this study was to examine the use of Fitoimun® mixed into crab feed to see survival, weight growth, specific daily growth rate, feed conversion ratio, and carapace width, which were reared in silvofishery ponds in Salo Palai Village. The study used a completely randomized design with 3 treatments and 3 replications. The treatment was Fitoimun® products containing Solanum ferox L and Boesenbergia pandurata, with a dose of 0 mL/kg, 20 mL/kg, 24 mL/kg. This study used mud crabs a weight of about 187-300 grams and a carapace width of about 95.0-110.5 mm. Feeding is given once every 2 days, in the morning at 07.00-08.00 and in the afternoon at 16.00-17.00. The feed given to crabs was measured as 5% of the crab's biomass weight. The results showed that the use of Fitoimun® products had no significant effect on survival, absolute weight growth, specific daily growth rate, carapace width, and feed conversion ratio, water quality during the study temperature 28.5°C, pH 7.5, DO 5.8 mg/L, salinity 13.8 mg/L pond. The relatively good Fitoimun® at a dose of 20 mL/kg mixed into mud crab (Scylla serrata) feed was able to increase growth, specific daily growth rate, feed conversion ratio, and carapace width. Keywords: Ftoimun®, growth survival, mud crab.
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Davenport, John, Martha Spikes, Sarah M. Thornton, and Bridget O. Kelly. "Crab-eating in the diamondback terrapinMalaclemys terrapin: dealing with dangerous prey." Journal of the Marine Biological Association of the United Kingdom 72, no. 4 (November 1992): 835–48. http://dx.doi.org/10.1017/s0025315400060070.
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Male diamondback terrapins,Malademys terrapin(190–240 g; 101–117 mm carapace length; 11–8 ±0–6 mm maximum jaw gape) selected small littorinids (<12 mm shell height) and mussels (<30 mm shell length) when offered prey of a range of sizes (at 26°C and 34‰. Jaw gape appeared to be the main constraint on feeding on molluscs. Responses to crabs were complex. Small crabs (10–25 mm carapace width) were eaten whole. Medium-sized crabs (30–50 mm carapace width) were ‘cropped’ (i.e.walking legs were eaten without killing the crabs). Large crabs (52–75 mm carapace width) were usually avoided, though terrapins sometimes took legs from pairs 3 or 4. Experiments with medium-sized crabs showed that diamondbacks evaluated crabs visually before attacking and preferred to eat crabs without chelipeds, rather than crabs with one or two chelipeds. Terrapins carried out attacks on medium-sized crabs from the side or rear and preferentially cropped leg pair 4 (the furthest from the chelipeds), even though leg pair 4 was significantly less valuable energetically than other leg pairs. Evidence is presented to show that cropping behaviour allows terrapins to exploit crabs which are too large to eat whole because of the constraints of jaw gape and the hard, smooth surface of the crab cephalothorax. Limb cropping is as energetically profitable as eating small crabs whole, but the threat posed by chelipeds causes terrapins to attack crab prey in the order small>medium>large.
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Baeza, J. A., W. Stotz, and M. Thiel. "Life history of Allopetrolisthes spinifrons, a crab associate of the sea anemone Phymactis clematis." Journal of the Marine Biological Association of the United Kingdom 81, no. 1 (February 2001): 69–76. http://dx.doi.org/10.1017/s0025315401003411.
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Allopetrolisthes spinifrons is an ectocommensal crab of the sea anemone Phymactis clematis. The population biology of A. spinifrons in north central Chile was examined between January and December 1996. During 1996, 74% of P. clematis in the rocky intertidal zone hosted at least one commensal crab. In most cases, one sea anemone was inhabited by a single adult crab, either male or female. A few sea anemones hosted two or more crabs, one usually being an adult and the others juveniles or small crabs that just had recruited to the host. The sex ratio of adult crabs was ∼1:1 during most months. Reproduction occurred with similar intensity throughout the year as indicated by the continuous presence of reproductive females. Similarly, recruitment of A. spinifrons occurred throughout the year with the exception of late winter when no megalopae and small juveniles were found on sea anemones. Fecundity of female crabs varied between 121 and 5661 eggs per female (6·9–19·2 mm carapace length) and was significantly higher during the austral winter (July) than during the summer (December). The fact that most sea anemones were inhabited by a single adult crab indicates that hosts may be monopolized by individual crabs. Resource requirements may prohibit adult crabs from sharing a host individual with another large crab, while adult tolerance towards juveniles may facilitate the maintenance of local populations.
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Sarower, M. G., S. Bilkis, M. A. Rauf, M. Khanom, and M. S. Islam. "Comparative Biochemical Composition of Natural and Fattened Mud Crab Scylla serrata." Journal of Scientific Research 5, no. 3 (August 29, 2013): 545–53. http://dx.doi.org/10.3329/jsr.v5i3.14082.
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The biochemical composition (proteins, lipid, ash and moisture) of different parts of the body (gill, meat, egg) of fattened and natural mud crab Scylla serrata was determined. Twenty four samples of S. serrata (12 from wild & 12 from fattening farm) of different sizes and sexes (half of the sample is male) were used in this study. The mean protein and lipid contents are significantly (p<0.05) higher in fattened crabs than natural in natural crabs regardless of size and sexes. Moisture and ash were higher in natural crab than in fattened ones. The highest and lowest moisture content was noticed in gills and eggs in both natural and fattened crabs. Protein and lipid contents were comparatively higher in eggs than in other body parts. Female crabs contained high protein and lipid than males in both natural and fattened crabs. From the results of this study it may considered that fattened crab might be comparatively superior to natural crabs as they appear to provide higher levels of protein and fat for human nutrition. Keywords: Biochemical composition; Natural and Fattened mud crab; Scylla serrata © 2013 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi: http://dx.doi.org/10.3329/jsr.v5i3.14082 J. Sci. Res. 5 (3), 545-553 (2013)
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Sasamu, Aditya, Winda M. Mingkid, and Revol D. Monijung. "The Identification Of Morphometric Characteristics And Fattenning Of Mud Crabs (Scylla spp.) In Para Island, Tatoareng District, Sangihe Islands Regency, North Sulawesi Province." JURNAL ILMIAH PLATAX 7, no. 1 (October 31, 2018): 42. http://dx.doi.org/10.35800/jip.7.1.2019.21491.
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The purpose of this study was to identify the morphometric characters of mangrove crabs Scylla spp. and to grow them on the island of Para Sangihe Islands Regency, North Sulawesi Province. There were 2 types of crabs found during crab’s collection. However, the most abundant one was Scylla serrata while the olivacea is only one tail. The results of this study indicate that mangrove crabs that were kept for 2 weeks feed on trash fish three times a day experience growth. Based on the results of the study, it can be concluded that: the type of crab found on Pulau Para, Tatoareng District, Sangihe Islands Regency, North Sulawesi Province were mostly S. serrata (34 tails) and one tail of S. olivacea. The fattening of mangrove crabs showed results on the body weight and carapace length.Further research on mangrove crabs needs to be done on different aspects such as preferable food and time of the abundancy.Keywords: Crab, Scylla spp., identification, fattening. ABSTRAK Tujuan dari penelitian ini adalah untuk mengidentifikasi karakter morfometrik kepiting bakau Scylla spp dan cara penggemukannya di Pulau Para Kabupaten Kepulauan Sangihe Provinsi Sulawesi Utara. Dua jenis kepiting bakau ditemukan saat pengumpulan data, namun yang ditemukan paling banyak adalah Scylla serrata, sedangkan S. olivacea hanya 1 ekor saja.Hasil penelitian ini menunjukan bahwa kepiting bakau yang dipelihara selama 2 minggu dengan diberi pakan ikan rucah sebanyak tiga kali sehari mengalami pertumbuhan. Berdasarkan hasil penelitian dapat disimpulkan bahwa: jenis kepiting yang ditemukan di Pulau Para Kecamatan Tatoareng Kabupaten Kepulauan Sangihe Provinsi Sulawesi Utara adalah Scylla serrata (34 ekor) dan S. olivacea (1 ekor). Penggemukan kepiting bakau dengan pakan ikan rucah tiga kali sehari menunjukan adanya pertumbuhan berat badan dan panjang lebar karapas. Penelitian lanjutan tentang kepiting bakau perlu dilakukan untuk melihat berbagai aspek seperti makanan kesukaan dan waktu kelimpahanya.Kata kunci : Kepiting, Scylla spp, identifikasi, penggemukan.
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Ribeiro, Pablo D., Oscar O. Iribarne, Luciano Jaureguy, Diego Navarro, and Eugenia Bogazzi. "Variable sex-specific mortality due to shorebird predation on a fiddler crab." Canadian Journal of Zoology 81, no. 7 (July 1, 2003): 1209–21. http://dx.doi.org/10.1139/z03-102.
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Male fiddler crabs compete for access to mates mainly by displaying an enlarged claw. One cost of this large claw is presumed to be higher exposure to predators. The fiddler crab Uca uruguayensis is used as a food source by several Neotropical migratory shorebirds. We investigated whether crab density and male claw-waving behaviour increase predation by shorebirds. The sex ratio of crabs on the surface was strongly male biased. Male crabs showed a daily succession of feedingwavingfeeding activities and their dry mass at the site decreased with a high density of crabs, suggesting stronger malemale competition than at sites with a low density of crabs. Sex-specific predation varied according to shorebird species. The Ruddy Turnstone (Arenaria interpres) preyed intensively on male crabs when they were courting and at sites with a high density of crabs, the Black-bellied Plover (Pluvialis squatarola) and the Lesser Golden Plover (Pluvialis dominica) preyed on crabs of both sexes, and the Whimbrel (Numenius phaeopus) foraged intensively on females. When estimating the net effect of all predators, we found that the four shorebird species together were able to consume between 0.1 and 0.2% of the crab population, and consumption did not differ between the sexes of crabs. These mortality rates indicate a low source of mortality, likely unable to produce deviations in the sex ratio of the population. Thus, our results indicate that a trait thought to be sexually selected does not necessarily lead to a disproportionate increase in mortality due to predation.
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Quezada-Villa, Katia, Zachary J. Cannizzo, Jade Carver, Robert P. Dunn, Laura S. Fletcher, Matthew E. Kimball, Ainslee L. McMullin, et al. "Predicting diet in brachyuran crabs using external morphology." PeerJ 11 (April 10, 2023): e15224. http://dx.doi.org/10.7717/peerj.15224.
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Morphological traits have often been used to predict diet and trophic position of species across many animal groups. Variation in gut size of closely related animals is known to be a good predictor of dietary habits. Species that are more herbivorous or that persist on low-quality diets often have larger stomachs than their carnivorous counterparts. This same pattern exists in crabs and in most species, individuals exhibit external markings on the dorsal side of their carapace that appear to align with the position and size of their gut. We hypothesized that these external markings could be used as an accurate estimate of the crab’s cardiac stomach size, allowing an approximation of crab dietary strategies without the need to sacrifice and dissect individual animals. We used literature values for mean diet and standardized external gut size markings taken from crab photographs across 50 species to show that percent herbivory in the diet increases non-linearly across species of brachyuran crab with the external estimate of gut size. We also used data from dissections in four species to show that external gut markings were positively correlated with gut sizes, though the strength of this correlation differed across species. We conclude that when rough approximations of diet quality such as percent herbivory will suffice, measuring external carapace markings in crabs presents a quick, free, non-lethal alternative to dissections. Our results also provide important insights into tradeoffs that occur in crab morphology and have implications for crab evolution.
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Pane, A. R. P., S. Mardlijah, H. Widiyastuti, M. Fauzi, T. Noegroho, T. Hidayat, and A. Zamroni. "Orange mud crab (Scylla olivacea) exploitation at Sorong waters." IOP Conference Series: Earth and Environmental Science 1224, no. 1 (August 1, 2023): 012011. http://dx.doi.org/10.1088/1755-1315/1224/1/012011.
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Abstract Mangrove forests along the vast coast of West Papua serve as the habitat for mud crabs, which are high-value economic resources marketed to various regions in Indonesia. However, intensive utilization impacts the sustainability of mangrove crab populations, especially orange mud crabs (Scylla olivacea). Exploitation studies need to be conducted for further use to manage crab resources. This study was conducted for six months, from April to September 2021, with a sample of 2,971 orange mud crabs. Data analysis was carried out using crab carapace width (CW) data to predict resource exploitation and sustainability. The caught orange mud crab size was 80-190 mm, with natural mortality (M) lower than fishing mortality (F). The exploitation of this crab has attained E = 0.72, which proves that overfishing. We can do the management of orange mud crabs by observing the size of mature gonads and spawning areas to provide an opportunity to increase the population in the waters.