Crab Species Research Articles

New genera and species of glaessneropsid crabs from the Lower and Middle Jurassic of France and Germany-Austria, and reconsolidation of Charassocarcinus Van Straelen, 1925

A new genus, Meroncarcinus, and two new species, M. boursicoti and Verrucarcinus marsae, are described from Callovian (Middle Jurassic) deposits of Calvados and Maine-et-Loire, France. New material of the type species of the genus Verrucarcinus, V. torosus, is examined, which improves our understanding of the peculiar morphology of this group of crabs. A new genus and species, Vilsercarcinus keuppi, is recognised from Lower-Middle Jurassic strata of Germany-Austria. Charassocarcinus, a Lower-Middle Jurassic crustacean genus of doubtful taxonomic affinity, is revived and here assigned to the Glaessneropsidae. All of this material forms the basis for a re-examination of the Glaessneropsidae, and an enhanced diagnosis is compiled. The morphology of Glaessneropsidae, one of the oldest known brachyuran families, is discussed; its complex orbital structure is remarkable for such an ancient group of crab and raises questions about its relationship with the basal brachyuran group Homolodromioidea. A solid support for a suprafamilial rank for the Glaessneropsidae is lacking.

A new host record for the pea crab Pinnotheres pisum (Linnaeus, 1767) (Decapoda: Pinnotheridae) in the western Mediterranean, with an update on host species

Pinnotheres pisum (Linnaeus, 1767) is one of the pinnotherid crab species with the highest number of reported bivalve hosts. Here we first report this species living in the bivalve Glossus humanus (Linnaeus, 1758), and provide an update on P. pisum symbiotic associations (i.e., known hosts), reaching up to 34 taxa. Partial sequences of the mitochondrial gene cytochrome c oxidase subunit I were first obtained from P. pisum and the G. humanus host from the Mediterranean Sea, confirming conspecificity with specimens from the Atlantic Ocean of the same species.

Experimental infection reveals mud crab, Scylla serrata is less susceptible than Scylla olivacea and shrimp, Penaeus vannamei to white spot syndrome virus (WSSV)

White spot syndrome virus (WSSV) causes severe mortality in farmed shrimps, besides causing infection in a wide range of crustaceans. Among the hosts, mud crabs are reported to be relatively resistant to the virus. To validate this, the present study investigated the susceptibility of two species of mud crabs, Scylla olivacea and S. serrata compared with shrimp, Penaeus vannamei to WSSV through experimental infection. Initially, to find out the pathogenicity of the virus, a quantified, 10-fold serially diluted WSSV inoculum was injected intramuscularly into shrimp and mud crabs. Cumulative mortality of 100% was observed in shrimp injected with 10−1 and 10−2 WSSV dilution at 5 and 6 day post-injection (dpi), respectively. However, injection of the virus inoculum of 10−1 dilution resulted in 100% and 85% cumulative mortality at 7 dpi in S. olivacea and S. serrata, respectively. The LD50 (lethal dose 50% endpoint) value of WSSV in P. vannamei, S. olivacea and S. serrata was determined to be 1.74 × 105, 3.80 × 106 and 8.51 × 106 viral copies per animal, respectively. PCR amplification of DNA extracted from different tissues of the experimental animals at 24, 48 and 72 h post-injection (hpi) confirmed the infection. A SYBR green-based real-time PCR assay revealed comparatively higher viral load in shrimp tissues (4.1 × 103, 2.8 × 106 and 4.3 × 107 copies/ 100 ng DNA in stomach, 1.0 × 103, 2.4 × 106 and 3.5 × 107 copies/ 100 ng DNA in gill and 3.5 × 102, 1.1 × 104 and 1.1 × 105 copies/ 100 ng DNA in hepatopancreas at 24, 48 and 72 h, respectively). The viral load in S. olivacea was estimated to be 2.9 × 103, 2.2 × 106 and 3.0 × 107 copies/ 100 ng DNA in the stomach, 7.1 × 102, 1.6 × 106 and 2.4 × 107 copies/ 100 ng DNA in gill and 2.0 × 102, 8.6 × 103& 7.8 × 104 copies/ 100 ng DNA and in S. serrata the viral copy numbers detected were 1.1 × 103, 1.7 × 106 and 1.8 × 107 copies/ 100 ng DNA in stomach, 6.6 × 102, 1.3 × 106 and 1.4 × 107 copies/ 100 ng DNA in gill and 5.8 × 101, 7.7 × 102 & 1.1 × 104 copies/ 100 ng DNA at 24, 48 and 72 h, respectively. A higher viral load was detected in the stomach tissue compared to the gill and hepatopancreas of all the experimental animals. Histological examination of the stomach and gill of P. vannamei, S. olivacea and S. serrata at different time points post-infection revealed characteristic WSSV pathology. Hepatopancreatic tubular epithelium showed no viral inclusions, though pathological changes could be noticed in the intertubular connective tissue. The most pronounced changes were found in the stomach epithelium of P. vannamei and S. olivacea, which revealed significant nuclear hypertrophy and large-sized inclusions, compared to S. serrata which showed relatively smaller-sized inclusion bodies.

Large‐scale changes in macrobenthic biodiversity driven by mangrove afforestation

Abstract Large‐scale anthropogenic mangroves have been constructed in coastal regions worldwide but our understanding of their ecological effects is limited. In particular, the question of whether and how anthropogenic mangroves influence biodiversity patterns remains elusive. Here, we investigated the influence of large‐scale anthropogenic mangroves on biodiversity patterns of mangrove macrobenthos. Specifically, we measure and seek to explain differences in species richness, abundance, assemblage composition and distance‐decay effect before and after the construction of anthropogenic mangroves. We surveyed assemblages of gastropod, bivalve and crab species over a wide latitudinal extent (24–28°N) in subtropical China. For each, we calculated species richness, abundance, assemblage composition and distance‐decay relationship before and after the construction of anthropogenic mangroves. After the large‐scale anthropogenic mangroves, we found species richness of gastropods, bivalves and crabs increased by 23.81%, 100% and 20%, respectively. The distance‐decay effects of gastropods and bivalves decreased by 25% and 91.43%, while that of crabs remained virtually unchanged, which mediated by increased dispersal rate of macrobenthos. With mangrove plantation, compositional similarity of crab and bivalve assemblages increased by 28.57% and 38.46%, suggesting that large‐scale monospecific planting exacerbate biotic homogenization. Altogether, these results indicate that large‐scale anthropogenic habitats increase the diversity of mangrove macrobenthos and change taxonomic compositions by reducing distance‐decay effects and increasing dispersal rate of macrobenthos. Synthesis and applications. We emphasize that afforestation of coastal wetlands can drive major changes in benthonic communities. Monitoring and assessing the ecological effects of the anthropogenic habitats for the presence of functional faunas will be important in determining the future coastal restoration and maintaining economic aquaculture. Quantifying those effects in terms of regional biodiversity composition will contribute to the management of coastal restoration to be based upon macroevidence rather than a one‐sided local perspective.

Molecular Phylogeny and Evolution of the Tuerkayana (Decapoda: Brachyura: Gecarcinidae) Genus Based on Whole Mitochondrial Genome Sequences.

Tuerkayana is of particular interest because it has been separated, in recent years, from Cardisoma and Discoplax but studies of its taxonomic status, especially from a whole mitochondrial genome perspective, have been lacking. In this study, the mitogenomes of four species (Tuerkayana magnum, Tuerkayana rotundum, Tuerkayana hirtipes, and Tuerkayana celeste) of Tuerkayana are sequenced and contrasted with other species in Brachyura for the first time. The phylogenetic tree of Brachyura, which includes 206 crab species (189 species of Brachyuran and 17 Anomura species) with a complete mitogenome, was constructed to evaluate the phylogenetic position of Tuerkayana and Gecarcinidae within Brachyuran, and explore the monophyly of Gecarcinidae. Furthermore, two single gene trees based on cox1 and 16SrRNA separately within interspecies of Gecarcinidae were reconstructed, providing molecular evidence for Tuerkayana and further clarifying the division of genera in Gecarcinidae. Based on the mitogenome dataset of 206 crabs, the branch-site model was utilized to explore selective pressure in individual codons with CodeML. The strong selective pressure shown in nad6 indicates that it may have played a significant role in the evolution of Gecarcinidae.

Illegal mining impacts on freshwater Potamonautid crab in a subtropical Austral highland biosphere reserve

The contamination of surface water by heavy metals, especially mercury, has become a global issue. This problem is particularly exacerbated in rivers and reservoirs situated in developing nations. Therefore, the objective of this study was to evaluate the potential contamination effects of illegal gold mining activities on freshwater Potamonautid crabs and to quantify the mercury levels in 49 river sites under three land use classes: communal areas, national parks and timber plantations. We used a combination of field sampling, multivariate analysis and geospatial tools to quantify mercury concentrations in relation to crab abundances. Illegal mining was prevalent throughout the three land use classes, with mercury (Hg) being detected in 35 sites (71.5 %). The mean range of Hg concentrations detected across the three–land uses was: communal areas 0–0.1 mg kg−1, national parks 0–0.3 mg kg−1 and timber plantations 0–0.06 mg kg−1. Mean Hg geo–accumulation index values showed strong to extreme contamination in the national park, with strong contamination observed for communal areas and timber plantations; furthermore, the enrichment factor for Hg concentrations in the communal and national park areas showed extremely high enrichment. Two crab species (i.e., Potamonautes mutareensis, Potamonautes unispinus) were found in the Chimanimani area, with P. mutareensis being the dominant taxon in the region across all the three land use areas. The national parks had higher total crab abundances than communal and timber plantation areas. We observed negative and significant K, Fe, Cu and B effects on total Potamonautid crab abundances, but surprisingly not for other metals such as Hg which might reflect their widespread pollution. Thus, illegal mining was observed to impact the river system, having a serious impact on the crab abundance and habitat quality. Overall, the findings of this study underscores the need to address the issue of illegal mining within the developing world as well as to establish concerted effort from all stakeholders (e.g., government, mining companies, local communities, and civil society groups) to help protect the less charismatic and understudied taxa. In addition, addressing illegal mining and protecting understudied taxa aligns with the SDGs (e.g. SDG 14/15-life below water/life on land) and contributes to global efforts to safeguard biodiversity and promote sustainable development.

Characteristics of Xanthidae Crab in the Intertidal Zone at Gili Meno Beach, West Nusa Tenggara

Gili Meno is one of the leading small (gili) tourist islands in North Lombok Regency, West Nusa Tenggara Province. Massive tourism activities have an impact on marine biota, including crabs. This research is to determine the characteristics of the crab family of Xanthidae in the intertidal zone of Gili Meno Beach, North Lombok Regency, West Nusa Tenggara Province. The research was conducted using an exploratory method by measuring the abiotic factors of the aquatic environment which is the habitat of crabs. Based on the research, two species of crab from the family of Xanthidae were obtained: Actaeodes tomentosus and Atergatis floridus. A. tomentosus has a relatively rough carapace while A. floridus has a relatively smooth carapace. Both like habitats with sandy substrates with reefs and coral rubble as protection from predators and waves. Abiotic factors: temperature and pH in the intertidal waters of Gili Meno Beach which are suitable for the growth, development and distribution of the two crab species.

Pola Persebaran dan Keanekaragaman Kelomang di Zona Litoral Pantai Leuweung Sancang Kabupaten Garut

The littoral zone of Leuweung Sancang Beach, Garut Regency has very diverse biodiversity, such as hermit crabs. This study aims to determine the distribution patterns and species diversity of hermit crabs in the littoral zone of Leuweung Sancang Beach. This research was conducted from February 2022 to June 2022. This research uses quantitative methods and sampling techniques using a 100 meter transect belt which is divided into 100 plots with a size of 1 x 1 meter. The stations used are Cibako 1 station, Cikujang Jambe 2 station, and Ciporeang 3 station. The results of this study obtained data on the distribution pattern of hermit crabs on Leuweung Sancang Beach, namely clusters with an id value > 1 obtained data on the diversity of hermit crabs consisting of 3 family, 5 genus, and 13 species. The results of the calculation of the ecological index on hermit crabs show that the average density of hermit crab species is 15.73 ind/m2, the average diversity index is 1.27 includes the moderate diversity category, the average uniformity index is 0.52 includes the moderate uniformity category, and the average dominance index is 0.39 includes the category of moderate dominance.

Preliminary assessment of genetic variation in the Japanese endemic freshwater crab, Geothelphusadehaani, based on mitochondrial DNA sequences.

Geothelphusadehaani, a freshwater crab species endemic to Japan, has the largest distribution range amongst the 19 known species in the country. Due to its low dispersal capability and restricted habitat to freshwater, it serves as an excellent model for understanding gene flow between geographically isolated populations. In this study, we analysed the genetic relationships of 26 G.dehaani populations collected from different locations in the Japanese archipelago using two mitochondrial DNA regions - cytochrome oxidase subunit I (COI) and cytochrome b (cytB). Our results from the analysis of molecular variance (AMOVA) revealed high genetic variation amongst populations and the phylogenetic analysis identified four geographical groups: Clade I - Honshu and Shikoku, Clade II - north-eastern Kyushu, Clade III - southern Kyushu and Clade IV - north-western Kyushu. Notably, Clade IV exhibited the highest genetic distance amongst the observed groupings. These findings highlight the need for further examination of G.dehaani in Kyushu, including morphological and behavioural traits, to better understand the observed diversity within the species in the region.

Chitin and chitosan extraction: A comparison of three crab species from fresh, brackish and marine water environments

Chitin was extracted from three species of crab obtained from biowastes of marine crab (Portunus. pelagicus), brackish water crab (Scylla sp.), and freshwater crab (Gecarcinucidea sp.). The chemical isolation involved 1 M NaOH and 1 M HCl for demineralization and deproteinization, respectively. 50 % NaOH deacetylated chitin to chitosan at 100 °C for 2 h. Highest chitin yield (15.11 %) was obtained from freshwater crab while no significant difference existed between brackish and marine. Chitosan from freshwater exhibited lowest ash content but highest solubility (65.94 %) and DDA (81.17 %). FTIR revealed functional groups peculiar to chitosan and further confirmed its α – group. XRD, SEM as well as bulk and tapped densities showed the smooth and porous nature of the chitosan. It was concluded that the variability of crabs' environment affected their shell formation and development which further impacted on chitin deposit. High solubility and DDA of freshwater crab chitosan makes it suitable as coagulant.

A new species of freshwater crab of the genus Chaceus Pretzmann, 1965 (Brachyura: Decapoda: Pseudothelphusidae) from La Guajira, including distribution and a key to the species of the genus.

We describe and illustrate a new species of Chaceus Pretzmann, 1965, from the Regional Natural Park of the Serranía de Perijá, La Guajira Department, Colombia. This increases the number of Chaceus species to ten, three of them with records only from Venezuela. The species of this genus are distributed in the Sierra de Santa Marta of Colombia and the Serranía de Perijá of Colombia and Venezuela. We distinguished the new species from its congeners mainly by the third maxilliped, with an exopod that is 0.60-0.62 the length of ischium, and by the morphology of the first male gonopod, particularly by the shapes of the mesial, marginal, and lateral processes. We include the distribution of the Chaceus species here and a key for the identification of the species based on the morphology of the first male gonopod.

The Uniqueness of Endemic Animals Canary Crab (Birgus latro) as The Largest Crab Species in The Phylum Arthropoda

Birgus latro or walnut crab is the largest land arthropod animal in the world, this crab has a unique and complex anatomy and body morphology that supports its survival. The research objective was to describe the anatomy, morphology, habitat, behavior, role, nutrition, reproductive system, immune system, gas exchange system, blood circulation, digestive system, excretory system, and Birgus latro osmoregulation. The research method used is literature review. This type of research is a form of qualitative descriptive research with review techniques from research journals on Birgus latro in Indonesia. This research was conducted by analyzing the results of research that had been published nationally and internationally relating to the life of Birgus latro. Walnut crabs live in areas that are damp and dark and avoid the sun to reduce the occurrence of evaporation on their bodies. Hard body parts such as shells, claws, and skin contain lots of calcium and chitin for self- defense and climbing coconut trees. The circulatory system of the walnut crab is open, this crab is also an osmoregulatory animal. The advice that the author can give for the preservation of walnut crabs is to provide outreach to the community regarding the importance of maintaining and preserving the existence of walnut crabs which are almost extinct. Establishing a walnut shell conservation center must also be carried out by the government to maintain the coconut crab population, as well as cultivate walnut crabs with the right procedure.

Seasonal variation in the land hermit crab, Coenobita rugosus H. Milne Edwards, 1837 (Decapoda, Anomura) and a preliminary study of land hermit crabs as a bioindicator of turtle nesting at Penghu County Wang-An Island green turtle nesting refuge, Taiwan

Abstract The present study surveyed the land hermit crab species, body size, shell type, and shell suitability, at five sites over four seasons in the Penghu County Wang-an Island Green Turtle Nesting Refuge. Coenobita rugosus H. Milne Edwards, 1837 was the only species recorded and found at three sites (Tiantai Hill, Xi’an Reservoir, and Tudigong). The density index of hermit crabs exhibited notable variations across the sites, showing no significant variation with the changing seasons. The bush habitat displayed a higher density index compared to the sand habitat. Additionally, the sites differed significantly in terms of the shell type and body size of the hermit crabs. Further, no significant relationship was established between abundance and weather factors or between crab abundance and sea turtle nesting. This investigation is a preliminary examination of the possibility of land hermit crabs being used as bioindicators for breeding of sea turtles.

Shell morphological variability of native snails and their vulnerability to introduced crab predators: Can sub-lethal injury provide prey with a reduced risk of lethal predation?

Historical differences in crab abundance and temperature, along with the natural history of specific species, have caused littorinid snail shells to vary in morphology across New England's rocky shores. In New England (USA) the native rough periwinkle, Littorina saxatilis, overlaps with two introduced crab species, Hemigrapsus sanguineus and Carcinus maenas. We examined the shell thickness and frequency of rough periwinkles that manifested crab attack scars (failed predation events that were recorded by morphological repairs of chipped shells) as an indication of selection for thick shells. Where crabs were less common in the north the rough periwinkle had thinner shells that make them more vulnerable to shell-breaking predators than those from the south. Evidence of scars was less frequent in the north likely because there were fewer predators, predators may have been less active, and thin-shelled snails were less likely to survive an attack. Scarred shells may also confer advantage to snails against future attack. Hemigrapsus sanguineus (but not Carcinus maenas) spent a significantly longer time handling scarred Littorina saxatilis over unscarred conspecifics, suggesting that while sub-lethal injuries in the form of shell scars can provide snails with reduced predation risk, the level of risk is species-specific. Introduced predators influencing the morphology of native prey provide a model system to investigate these ecological and evolutionary changes on a rapid time-scale.

Morphology of the gastric mill teeth in dotillid crabs (Crustacea: Brachyura: Dotillidae) from Indonesia.

The gastric mill is a prominent structure in the digestive system of brachyuran crabs, consisting of a median tooth plate and a pair of lateral tooth plates. Among crab species that are deposit feeders, the morphology and size of the gastric mill teeth are correlated with the preferred substrate types and food spectrum. In this study, we provide a detailed description of the morphology of the median and lateral teeth of the gastric mills in eight species of dotillid crabs from Indonesia, and compare them in relation to habitat preferences and molecular phylogeny. Ilyoplax delsmani, Ilyoplaxorientalis, and Ilyoplaxstrigicarpus have comparatively simple shapes of their median and lateral teeth, with fewer teeth on each lateral tooth plate compared to Dotilla myctiroides, Dotillawichmanni, Scopimera gordonae, Scopimeraintermedia, and Tmethypocoelis aff. ceratophora, which have more complexly shaped median and lateral teeth, with a greater number of teeth on each lateral tooth plate. The number of teeth on lateral tooth correlates with habitat preference, that is, dotillid crabs inhabiting muddy substrata have fewer teeth on the lateral tooth plate, and those inhabiting sandy substrata have a more teeth. Phylogenetic analysis using partial COI and 16S rRNA genes supports that teeth morphology is similar among closely related species. Therefore, the description of median and lateral teeth of the gastric mill is expected to contribute to the systematic study of dotillid crabs.

Grooming and agonistic behaviors in the semi-terrestrial crabsOcypode quadrata(Fabricius, 1787) andMinuca(Uca) burgersi(Holthuis, 1967) (Decapoda: Brachyura: Ocypodidae)

AbstractGrooming behaviors reduce body fouling and are well documented in crustaceans. There are more detailed laboratory-based grooming studies on fully aquatic crabs compared to semi-terrestrial crabs. By contrast, semi-terrestrial crabs are predicted to have different grooming time budgets than fully aquatic crabs because semi-terrestrial crabs are not constantly submerged in water that can mechanically remove sedimentary fouling, whereas fully aquatic crustaceans have increased fouling from algae and epibionts. We studied the grooming behaviors of two semi-terrestrial crab species. Crabs (N = 50 ghost crabs, Ocypode quadrata (Fabricius, 1787); N = 50 fiddler crabs, Minuca (Uca) burgersi (Holthuis, 1967)) were observed in isolation for 45-min trials. We recorded grooming frequency, location, appendage, and time. Ghost crabs were also observed in agonistic encounters to determine how grooming varied in the presence of a conspecific individual. Ghost crabs and fiddler crabs have different grooming time budgets, (0.526 and 0.895%, respectively) with both species having lower grooming time budgets than fully aquatic crustaceans. Some similarities and differences in grooming between the two semi-terrestrial crabs exist, with both species frequently grooming their eyes and maxillipeds using a brush or scrape mechanism, but with fiddler crabs using their eyes as a grooming appendage more frequently than ghost crabs. Ghost crab males groom less than females, whereas fiddler crab males and females groom equally. In agonistic interactions in ghost crabs, the grooming time budget decreased compared with isolated observations and individuals engaged in a “playing dead” behavior (thanatosis) after engaging in a fight. Semi-terrestrial crabs were found to groom significantly less than fully aquatic crustaceans.

Two new species of hairy crabs (Pilumnidae) and the first record of Crinitocinus alcocki (Borradaile, 1900) (Acidopsidae) (Crustacea: Brachyura) from Taiwan.

Two new species of pilumnid crabs, Heteropilumnus planus n. sp. and Pseudolitochira taiwang n. sp., are described from reefs in Taiwan. Heteropilumnus planus n. sp. is most similar to H. hirsutior (Lanchester, 1900) from Singapore and Japan, but can easily be distinguished by its distinctly flatter carapace, different anterolateral carapace armature, longer ambulatory legs, and male first gonopod structure. Pseudolitochira taiwang n. sp. is most similar to P. crinita Ng & Clark, 2022, from Papua New Guinea but can easily be separated by its carapace physiognomy, armature of the anterolateral carapace margin and proportionately shorter ambulatory legs. Heteropilumnus setosus (A. Milne-Edwards, 1873) is also transferred to Pseudolitochira; and compared with P. taiwang n. sp. The rarely reported acidopsid, Crinitocinus alcocki (Borradaile, 1900) is also recorded from Taiwan for the first time, substantially extending its known range northwards.

Dietary effects on larval survival and development of three sesarmid crabs

Semi-terrestrial brachyuran sesarmid crabs are the most diverse and important faunal components of mangrove forest and temperate coastal communities worldwide. To establish a stable larval rearing method for understanding their larval developmental processes including molecular mechanisms of molting and metamorphosis, we examined the effects of diet on the survival and growth of three sesarmid crabs, Chiromantes haematocheir, Orisarma intermedium, and O. dehaani under larval development. Zoea of each species, immediately after hatching, were reared under different feeding conditions as follows: non-feeding; fed only nutrition-enriched rotifers; fed only Artemia (brine shrimp) nauplii; and fed a combination of both nutrition-enriched rotifers and brine shrimp. Larvae of each species survived almost to megalopa when they were fed both rotifer and brine shrimp, but all C. haematocheir larvae had died by zoeal stage 2 when they were only fed brine shrimp. Chiromantes haematocheir larvae could survive into the megalopa stage when fed only nutrition-enriched rotifer, whereas both O. dehaani and O. intermedium showed 50% or less survival and metamorphosis rates into megalopa. The duration of larval development and survival rates of the three crabs were shorter and higher, respectively, in the mixed feeding group (both rotifer and brine shrimp) than when only fed rotifer or brine shrimp. This study provides baseline knowledge of the interspecific variability in larval survival and duration under different diets for sympatric sesarmid crab species.

Genomic analyses indicate two blue swimmer crab species in Australia, evidence for natural interspecific hybridization and genetic structure within species with implications for fisheries management and stock enhancement

Blue swimmer crab species are widely distributed in Indian and west Pacific Oceans including the coastline around Australia and have been identified as potential candidates for stock enhancement. A recent taxonomic review revealed the presence of two blue swimmer crab species in Australia, namely Portunus armatus which is found around most of the Australian coastline, and Portunus pelagicus which is found in the northern coast where it is sympatric with P. armatus. It is important to understand population structure and genetic diversity of Portunus spp. to efficiently manage stocks. In the present study we investigated species classification and population structure of Portunus spp. in Australia using full and partial genomic information, namely mitochondrial COX1 gene sequences derived from whole genome sequencing and single nucleotide polymorphic (SNP) markers developed from partial genome sequencing. Blue swimmer crab samples were collected from the western (n = 52), northern (n = 17) and eastern (n = 110) coasts of Australia. Genetic diversity and population genetic structure were assessed for within and between region variation. Our genomic results indicated the presence of two blue swimmer crab species in Australia. One, namely, P. pelagicus was found only in Northern Territory (Darwin), and other, namely P. armatus was found around Australia. There was evidence of natural hybridisation between two species in Northern Territory (Darwin) where they were sympatric. P. armatus populations from the western, northern and eastern regions were genetically different although there were no significant genetic differences observed between the Queensland and New South Wales populations nor between the two neighbouring populations in Western Australia. Results found in the present study supports the view that the P. armatus populations in western, northern and eastern regions of Australia should be treated as at least three different stocks. A lack of genetic structuring along the eastern coast suggests blue swimmer crabs can be considered as a single stock along the sampled range at least in relation to fisheries enhancement, release programs and broodstock management.

Erratum: Eyestalk Ablation to Increase Ovarian Maturation in Mud Crabs.

Erratum: Eyestalk Ablation to Increase Ovarian Maturation in Mud Crabs.