Crab Research Articles

Larval cycle, ecology and distribution of the red mangrove crab ( Ucides occidentalis ) in the Gulf of Guayaquil, Ecuador: understanding multiple impacts on fishery sustainability

Larval cycle, ecology and distribution of the red mangrove crab ( Ucides occidentalis ) in the Gulf of Guayaquil, Ecuador: understanding multiple impacts on fishery sustainability

Decadal changes in size and intertidal reproductive output by the non-native Asian shore crab ( Hemigrapsus sanguineus )

Decadal changes in size and intertidal reproductive output by the non-native Asian shore crab ( Hemigrapsus sanguineus )

Comparative experimental taphonomy of eight marine arthropods indicates distinct differences in preservation potential

AbstractGlobal biodiversity patterns in deep time can only be understood fully when the relative preservation potential of each clade is known. The relative preservation potential of marine arthropod clades, a diverse and ecologically important component of modern and past ecosystems, is poorly known. We tackled this issue by carrying out a 205‐day long comprehensive, comparative, taphonomic experiment in a laboratory by scoring up to ten taphonomic characters for multiple specimens of seven crustacean and one chelicerate species (two true crabs, one shrimp, one lobster, one hermit crab, one stomatopod, one barnacle and one horseshoe crab). Although the results are preliminary because we used a single experimental setup and algal growth partially hampered observations, some parts of hermit crabs, stomatopods, swimming crabs and barnacles decayed slowly relative to other parts, implying differential preservation potentials within species, largely consistent with the fossil record of these groups. An inferred parasitic isopod, manifested by a bopyriform swelling within a hermit crab carapace, decayed relatively fast. We found limited variation in the decay rate between conspecifics, and we did not observe size‐related trends in decay rate. Conversely, substantial differences in the decay rate between species were seen after c. 50 days, with shrimps and stomatopods decaying fastest, suggesting a relatively low preservation potential, whereas the lobster, calico crabs, horseshoe crabs and barnacles showed relatively slow decay rates, suggesting a higher preservation potential. These results are supported by two modern and fossil record‐based preservation potential metrics that are significantly correlated to decay rate ranks. Furthermore, we speculate that stemward slippage may not be ubiquitous in marine arthropods. Our results imply that diversity studies of true crabs, lobsters, horseshoe crabs and barnacles are more likely to yield patterns that are closer to their true biodiversity patterns than those for stomatopods, shrimps and hermit crabs.

First record of the Bengal fiddler crab Uca (Austruca) bengali Crane, 1975 (Braychura: Ocypodidae) from Kuakata National Park, Bangladesh

Abstract not available
 Dhaka Univ. J. Biol. Sci. 26(2): 199-203, 2017 (July)

Optimization of stocking density in intensification of mud crab Scylla serrata cultivation in the resirculation system

<p class="NoParagraphStyle"><strong>ABSTRACT</strong></p><p class="NoParagraphStyle"><strong> </strong></p><p class="NoParagraphStyle">This study aimed to determine optimum stocking density of mud crab <em>Scylla serrata</em> through the applied of different stocking density in every treatment in recirculation system. Experimental design used was complete randomized design (CRD) with three density treatments which were 5 (P1), 10 (P2), and 15 ind/container (P3). All treatments replicated three times. The crab with the average of body weight 150 g/ind cultured in a plastic box (40×30×30 cm). Crab was cultured within 60 days and were fed two times a day by at satiation method. The result showed that P2 treatment gave the best result of mangrove crabs production performance among all treatments with 73.33±5.77% survival rate, 0.68±0.01 g/ind/day absolute growth rate and food conversion ratio 10.11±0.01. Treatment P1 gave the good response of stress, it indicated by the lowest glucose of all tretamnets at the level of 31.91 mg/dL in the end of treatment periods. The water quality during study period was fluctuative as affected by different stocking density in the treatments.</p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle">Keywords: mud crab, stocking density, production performance</p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle"><strong> </strong></p><p class="NoParagraphStyle"><strong>ABSTRAK</strong><strong></strong></p><p class="NoParagraphStyle"><strong> </strong></p><p class="NoParagraphStyle">Penelitian ini bertujuan untuk menentukan padat tebar optimal kepiting bakau <em>Scylla serrata</em> melalui penerapan kepadatan tebar yang berbeda pada setiap perlakuan dalam sistem resirkulasi. Rancangan penelitian yang digunakan adalah rancangan acak lengkap dengan tiga perlakuan yaitu 5 (P1), 10 (P2), dan 15 ekor/wadah pemeliharaan (P3) dengan tiga ulangan. Kepiting bakau yang digunakan memiliki berat rata-rata 150 g/ekor. Wadah pemeliharaan yang digunakan selama pemeliharaan adalah kontainer plastik yang berukuran 40×30×30 cm. Pemeliharaan kepiting bakau dilaksanakan selama 60 hari dan diberikan pakan berupa ikan rucah dua kali sehari secara at satiation. Penelitian menunjukkan bahwa perlakuan P2 memberikan hasil kinerja produksi terbaik dibandingkan perlakuan lainnya dengan nilai kelangsungan hidup 73,33±5,77%, laju pertumbuhan mutlak 0,68±0,01 g/ekor/hari, dan rasio konversi pakan 10,11±0,01. Perlakuan P1 menunjukkan respons stres yang baik dengan memiliki nilai kadar glukosa paling rendah dari perlakuan lain yaitu 31,91 mg/dL pada akhir masa pemeliharaan. Kualitas air selama penelitian memiliki nilai yang fluktuatif di setiap perlakuan sebagai efek adanya perbedaan jumlah padat tebar setiap wadahnya</p><p class="NoParagraphStyle"> </p><p>Kata kunci: kepiting bakau, padat tebar, kinerja produksi</p>

Optimization of stocking density in intensification of mud crab Scylla serrata cultivation in the resirculation system

<p class="NoParagraphStyle"><strong>ABSTRACT</strong></p><p class="NoParagraphStyle"><strong> </strong></p><p class="NoParagraphStyle">This study aimed to determine optimum stocking density of mud crab <em>Scylla serrata</em> through the applied of different stocking density in every treatment in recirculation system. Experimental design used was complete randomized design (CRD) with three density treatments which were 5 (P1), 10 (P2), and 15 ind/container (P3). All treatments replicated three times. The crab with the average of body weight 150 g/ind cultured in a plastic box (40×30×30 cm). Crab was cultured within 60 days and were fed two times a day by at satiation method. The result showed that P2 treatment gave the best result of mangrove crabs production performance among all treatments with 73.33±5.77% survival rate, 0.68±0.01 g/ind/day absolute growth rate and food conversion ratio 10.11±0.01. Treatment P1 gave the good response of stress, it indicated by the lowest glucose of all tretamnets at the level of 31.91 mg/dL in the end of treatment periods. The water quality during study period was fluctuative as affected by different stocking density in the treatments.</p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle">Keywords: mud crab, stocking density, production performance</p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle"><strong> </strong></p><p class="NoParagraphStyle"><strong>ABSTRAK</strong><strong></strong></p><p class="NoParagraphStyle"><strong> </strong></p><p class="NoParagraphStyle">Penelitian ini bertujuan untuk menentukan padat tebar optimal kepiting bakau <em>Scylla serrata</em> melalui penerapan kepadatan tebar yang berbeda pada setiap perlakuan dalam sistem resirkulasi. Rancangan penelitian yang digunakan adalah rancangan acak lengkap dengan tiga perlakuan yaitu 5 (P1), 10 (P2), dan 15 ekor/wadah pemeliharaan (P3) dengan tiga ulangan. Kepiting bakau yang digunakan memiliki berat rata-rata 150 g/ekor. Wadah pemeliharaan yang digunakan selama pemeliharaan adalah kontainer plastik yang berukuran 40×30×30 cm. Pemeliharaan kepiting bakau dilaksanakan selama 60 hari dan diberikan pakan berupa ikan rucah dua kali sehari secara at satiation. Penelitian menunjukkan bahwa perlakuan P2 memberikan hasil kinerja produksi terbaik dibandingkan perlakuan lainnya dengan nilai kelangsungan hidup 73,33±5,77%, laju pertumbuhan mutlak 0,68±0,01 g/ekor/hari, dan rasio konversi pakan 10,11±0,01. Perlakuan P1 menunjukkan respons stres yang baik dengan memiliki nilai kadar glukosa paling rendah dari perlakuan lain yaitu 31,91 mg/dL pada akhir masa pemeliharaan. Kualitas air selama penelitian memiliki nilai yang fluktuatif di setiap perlakuan sebagai efek adanya perbedaan jumlah padat tebar setiap wadahnya</p><p class="NoParagraphStyle"> </p><p>Kata kunci: kepiting bakau, padat tebar, kinerja produksi</p>

Molecular evidence for the assignment of the Cameroonian freshwater crab genus Louisea Cumberlidge, 1994, to the Afrotropical subfamily Potamonautinae Bott, 1970 (Crustacea: Potamoidea: Potamonautidae)

The family Potamonautidae Bott, 1970, currently comprises 19 genera assigned to two subfamilies (Potamonautinae Bott, 1970, and Deckeniinae Hilgendorf, 1869) based on morphological and molecular studies (Cumberlidge 1999; Daniels et al. 2006a, 2015; Cumberlidge et al. 2008; Cumberlidge & Ng 2009). All members of this family are endemic to the Afrotropical zoogeographical region that includes most of continental Africa plus the continental islands of Madagascar, the granitic Seychelles, Socotra, and the southern Arabian Peninsula. Seven genera from sub-Saharan Africa are presently assigned to Potamonautinae (see Cumberlidge et al. 2008; Daniels et al. 2015): Erimetopus Rathbun, 1894, Liberonautes Bott, 1955, Louisea Cumberlidge, 1994, Potamonautes Bott, 1970, Potamonemus Cumberlidge & Clark, 1992, Sudanonautes Bott, 1955, and Platythelphusa A. Milne-Edwards, 1887. Twelve genera from West and East Africa, Seychelles, and Madagascar are assigned to Deckeniinae (see Cumberlidge et al. 2008; Meyer et al. 2014; Daniels et al. 2015): Deckenia Hilgendorf, 1869, Seychellum Ng, Števčić & Pretzmann, 1995, Globonautes Bott, 1959, Afrithelphusa Bott, 1969, Boreas Cumberlidge & Sternberg, 2002, Foza Reed & Cumberlidge, 2006a, Hydrothelphusa A. Milne-Edwards, 1872, Madagapotamon Bott, 1965, Malagasya Cumberlidge & Sternberg, 2002, Marojejy Cumberlidge, Boyko & Harvey, 2000, Skelosophusa Ng & Takeda, 1994, and Glabrithelphusa Meyer, Cumberlidge & Koppin, 2014.

Survival and metamorphosis rate of swimming crab Portunus pelagicus larvae with the use of phytoecdysteroid in the artificial feed

<p class="NoParagraphStyle"><strong>ABSTRACT</strong></p><p class="NoParagraphStyle"><strong> </strong></p><p class="NoParagraphStyle">The survival rate of blue swimming crabs and the larval metamorphosis processes are still low in hatcheries. The objective of this study was to evaluate the effects of different phytoecdysteroids doses on both the survival and the rate of Blue swimmer crab larvae metamorphosis. The study consisted of four different phytoecdysteroids treatments, namely: control (0 mg/100 g of feed), 1 mg/100 g of feed, 2 mg/100 g of feed, and 4 mg/100 g of feed. Each treatment was replicated three times. The survival rate of the larvae was analyzed through analysis of variance, while the rate of larval metamorphosis was descriptively analyzed. The results showed that the dose of phytoecdysteroid of 2 mg/100 g of artificial feed resulted in the highest survival and the fastest metamorphosis speed of crab larvae for zoea-2 and zoea-3, and the dose of 4 mg/100 g of artificial feed for stadia megalopa and crablet.</p><p class="NoParagraphStyle"> </p><p class="NoParagraphStyle">Keywords: phytoecdysteroids, survival rate, metamorphosis, blue swimming crab</p><p class="NoParagraphStyle"><strong> </strong></p><p class="NoParagraphStyle"><strong> </strong></p><p class="NoParagraphStyle"><strong>ABSTRAK</strong><strong></strong></p><p class="NoParagraphStyle"><strong> </strong></p><p class="NoParagraphStyle">Kelangsungan hidup rajungan dalam pembenihan masih rendah, dan proses metamorfosis larva masih lambat. Tujuan penelitian ini adalah untuk mengevaluasi pengaruh pemberian fitoekdisteroid dosis berbeda terhadap kelangsungan hidup dan kecepatan metamorfosis larva rajungan. Penelitian ini terdiri atas empat perlakuan dosis fitoekdisteroid yang berbeda, yaitu: kontrol (0 mg/100 g pakan), 1 mg/100 g pakan, 2 mg/100 g pakan, dan 4 mg/100 g pakan dengan masing-masing perlakuan dilakukan tiga kali ulangan. Kelangsungan hidup larva dianalisis menggunakan analisis sidik ragam, sedangkan kecepatan metamorfosis larva dianalisis secara deskriptif. Hasil penelitian menunjukkan bahwa dosis fitoekdisteroid sebanyak 2 mg/100 g pakan buatan menghasilkan kelangsungan hidup tertinggi dan proses metamorfosis larva rajungan tercepat untuk stadia zoea-2 dan zoea-3, serta dosis 4 mg/100 g pakan buatan untuk stadia megalopa dan crablet.</p><p class="NoParagraphStyle"> </p><p>Kata kunci: fitoekdisteroid, kelangsungan hidup, metamorfosis, rajungan</p>

Effects of Increasing Chitosan Nanofibre Volume Fraction on the Mechanical Property of Hydroxyapatite

This work attempted to synthesize chitosan (CH) nanofibre from crab shell and hydroxyapatite, HA, from limestone with the objective of studying the effects of increasing volume fraction of chitosan nanofibre on the mechanical properties of HA. Mechanical characterization of different fraction composite was carried out to study the effects of increasing volume fraction of chitosan nano fibre on the mechanical properties of HA. In addition, surface characterization of the composite was carried out using Fourier Transform Infrared Spectrometry, FT-IR. Results obtained indicated that the optimum mechanical properties were obtained at a volume fractions of 30: 70, CH: HA respectively; average compressive strength of 10.12 MPa; average tensile strength of 173.9 MPa; average hardness value of 420.80 HV; average fracture toughness of 14.72 MPa.m1/2; average elastic modulus of 0.1583 GPa and average bending strength of 157.96 MPa were obtained for this optimum volume fractions. Increasing volume fractions of chitosan nanofibre was therefore found to result in decrease in compressive strength, hardness and elastic modulus of HA while its tensile strength, bending strength and fracture toughness increased. The FTIR revealed that possible interaction between the NH2 group and the primary and secondary –OH group of CH with Ca2+ (metal coordination interaction) of HA might be responsible for the higher mechanical property of HA. In conclusion, it was found that increasing chitosan volume fraction in chitosan/HA composite results in increasing strength of hydroxyapatite, consequently enhancing its load bearing ability.

The Land Crabs of Costa Rica

The land crabs of Costa Rica, members of the families Gecarcinidae and Coenobitidae, are described and keys are presented for their identification. A review of the recent literature is presented and also a brief discussion of the habits and life history of these land crabs. Species accounts include information on common name, range, collecting sites, size, habitat and color.

Hetero-atom Decoration of Activated Carbon Without Post-treatment

In this work, we attempt to decorate heteroatoms, including nitrogen and sulphur, into activated carbon without post-treatment. These atoms can be introduced into the carbon framework by the strong acid/base reactions after the carbonisation and activation. Raw materials, which contain the desired heteroatoms, were selected so that the obtained activated carbon would have the heteroatom without the harmful chemical process. Crab and shrimp shells were used as the raw material for nitrogen-doped activated carbon since they both contain chitin, which is the organic compound containing nitrogen atom. Similarly, lignite from Mae Moh (Lampang province, Thailand) which has high sulphur content, is suitable for the preparation of sulphur-doped activated carbon. Two types of activating agents, K2CO3 and KOH, were used as the activating agents and the effect from the ratio of raw materials to activating agents were studied. The surface area and the pore structures were determined by nitrogen adsorption analysis and the elemental compositions were characterised by CHNS analysis. It is found that activated carbon prepared from shrimp shells has a higher nitrogen content (1.40 wt%) than that prepared from crab shells (0.47 wt%). The specific area of the obtained activated carbonwas as high as 2,100 m2/g with the optimal condition. Sulphur-doped activated carbon can be easily preparedfrom lignite with high sulphur contents (14.34 wt%) and commercially comparable specific surface area (650 m2/g).

Effects of the bioturbating crab <i>Macrophthalmus</i> <i>japonicus</i> on abiotic and biotic tidal mudflat characteristics in the Tama River, Tokyo Bay, Japan

Effects of the bioturbating crab <i>Macrophthalmus</i> <i>japonicus</i> on abiotic and biotic tidal mudflat characteristics in the Tama River, Tokyo Bay, Japan

<i>Haliphthoros sabahensis</i> sp. nov. Isolated from Mud Crab <i>Scylla tranquebarica</i> Eggs and Larvae in Malaysia

<i>Haliphthoros sabahensis</i> sp. nov. Isolated from Mud Crab <i>Scylla tranquebarica</i> Eggs and Larvae in Malaysia

Toxicity evaluation of ballast water discharged at The Onne Port complex using the microtox assay

Ballast water from ninety-six (96) International vessels calling the Onne Port complex were analyzed for physicochemical and acute toxicity test using the bioluminescence bacteria (Vibrio fisheri) from October 2015 to September 2016. The result of the microtox assay showed that the ballast water were generally toxic in the months under review. The Tanker vessels were generally more toxic than the RoRo/Container carriers. For the RoRo/Container carriers, the EC50 values for the 5 minutes and 15 minutes microtox assay ranged from 7.99± 2.45% in November, 2015 to 44.04±1.70% in June 2016 and 8.97±1.07% in November 2015 to 44.98±11.13% in June 2016. Similarly, for the tanker vessels, the EC50 values ranged from 5.63±1.97% in June 2016 to 28.17±1.71% in January 2016. In comparison to the reference chemical (Zinc sulphate) for the 5 minutes and 15 minutes microtox assay test, the EC50 values ranged from 1.00 ± 0.24% to 3.49±0.61% and 2.03±1.15% to 5.16±2.99% respectively. The seawater which served as controls were generally not toxic as the EC50 values was 100% from October 2015 to September 2016. The discharge of these ballast water poses a major environmental threat to the water quality and Port infrastructures at the Onne Port complex as contaminants may find their way into the food chain/food web and bioaccumulate in the tissues of indigenous biota (microorganisms, crabs, mangrove oysters and fin-fishes). This research work flags off the need for the regulators of Maritime Safety and Administration in Nigeria to monitor closely International vessels calling at major ports in Nigeria and the need to begin to domesticate some of the IMO guidelines on Ballast water management and ensure strict compliance.Key words: Ballast water, Toxicity, Vibrio fischeri, International Maritime Organization

Influence of Trichodactylus fluviatilis on Leaf Breakdown in Streams: Understanding the Role of Freshwater Crabs in Detritus-based Food Webs.

Larissa Costa, Walace Kiffer Jr., Cinthia Casotti, Juliana Rangel, and Marcelo Moretti (2016) Freshwater crabs can affect leaf breakdown by consuming leaves or invertebrate shredders. The aims of this study were to analyze the gut content of Trichodactylus fluviatilis and evaluate the influence of this macroconsumer on leaf breakdown. For this, we (i) performed gut analyses of 55 individuals of T. fluviatilis and (ii) determined leaf decay rates and FPOM production in laboratory trials containing crabs and the caddisfly shredder Triplectides sp., alone and together, and leaves differing in quality. We hypothesized that T. fluviatilis feeds both on leaves and Triplectides sp. and, consequently, leaf decay rates would be lower when these organisms were together. The main food categories in T. fluviatilis guts were algae and FPOM, while CPOM and animal tissue were rare. Leaf decay rates and FPOM production did not differ across shredder treatments or leaf species. However, the survival of Triplectides sp. was higher when alone. The results support the potential for participation of T. fluviatilis in leaf breakdown and demonstrated that, in spite of the high abundances of algae and FPOM in the gut content, adults of this species have the potential to feed both on leaf litter and larvae of Triplectides sp. However, the hypothesis of this study was only partially corroborated because decay rates did not change across treatments.

Applying of Stress Collectives in the Design of Structural Elements of Heavy Load-Bearing Structures

The article deals with the analytical-experimental means of determining the rate, respectively, the degree of fatigue damage for the analysis of limit state of main supporting structural element of the main beam on the twin beam of the bridge crane. Taken into account it is the dynamic effect of load hoisting and the application of load collectives and the position of the crane crab obtained experimentally for the development of stress collectives. In this analysis, the expression of the link between random load process and fatigue properties of material the Palmgren-Miner linear theory on fatigue damage accumulation was applied.

Ptychophallus costaricensis , a new freshwater crab from Costa Rica

A new freshwater crab of the genus Ptychophallus is described from Costa Rica, based on the morphology of the gonopod. The species lives under rocks in small streams at an altitude of approximately 1,300 m and at a median water temperature of 16 C. twelve specimens were collected at Quebrada Los Tubos and thirty-two at Rio Naranjo, Santa Maria de Dota, both sites in the Province of San Jose, Distribution is apparently restricted to the southwest of Costa Rica.

Small-scale mud crab Scylla sp. fattening in Shyam-nagar, Satkhira

Abstract not availableBangladesh J. Zool. 44(1): 163-166, 2016

In situ Synthesis of Nitrogen/Oxygen Co-doped Porous Carbons Derived from Crab Shells and Their Application as Supercapacitor Electrode Materials

In situ Synthesis of Nitrogen/Oxygen Co-doped Porous Carbons Derived from Crab Shells and Their Application as Supercapacitor Electrode Materials

Evolution of male copulatory organs in box crabs (Decapoda: Eubrachyura: Calappidae De Haan, 1833)

Male genitalia are extraordinarily diverse, and this diversity makes them valuable taxonomic and phylogenetic markers. Genitalia of true crabs (Brachyura) consist of two pairs of modified appendages, or gonopods. The first pair is tubular, and holds the second pair during copulation. Whether the second pair is shorter or longer than the first pair has important implications for copulation. Its length is often similar in closely related species, e.g. within genera and families, but is highly variable in the Brachyura at large. The genus Calappa Weber, 1795 contains species with long, short, and intermediate-length second gonopods, representing an unusually variable pattern. We investigated the evolution of the second gonopods in Calappa and other members of Calappidae. We assembled a molecular multi-locus phylogeny (mitochondrial marker: COI and 16S, nuclear marker: Enolase, H3 and 28S). Based on this phylogeny, long second gonopods are the ancestral state for Calappa as well as Calappidae in general. Short second gonopods evolved once, while intermediate-length second gonopods evolved independently at least four times. Scanning electron microscopic images of second gonopods of 22 species of Calappidae reveal that shortening of the second gonopod is always achieved by a shortening of the terminal segment. Congruently, taxon-specific structures at the tip of the terminal segment of the second gonopod, such as spines and pistil-like protrusions, are limited to long second gonopods. Based on current knowledge, a shortening of the second gonopod should be accompanied by extensive changes in the copulatory mechanism of males and females, including changes to the copulatory mechanism, mechanism of species recognition, targets of sexual selection, and the potential for sperm removal. Calappa therefore provides a vital example for the study of changes in copulatory mechanisms.