Portunid Crab Research Articles

Spatio-temporal Distribution of Portunid Crabs within the Gulf of Mannar, Southeast Coast of India

Spatio-temporal Distribution of Portunid Crabs within the Gulf of Mannar, Southeast Coast of India

New report of decapod crustaceans from the Miocene of Iran

We report some brachyuran crabs from the late Miocene of Dar Pahn unit, Makran Province, Iran. The studied specimens have been assigned to Ixoides MacGilchrist, 1905, with I. miocenicus n. sp. (Leucosiidae Samouelle, 1819) and Persianus arcuatus n. gen., n. sp. (Portunidae Rafinesque, 1815). Ixoides miocenicus n. sp. represents the first fossil representative of the genus, enlarging its stratigraphic range to the Miocene. Persianus arcuatus n. gen., n. sp. represents the first report of a portunid crab from the Miocene of Iran. We also report an indeterminate majoid crab, representing the first report for the Majoidea from the Miocene of Iran. Finally, one portunid crab is compared with Persianus n. gen. based on some similar morphological characters.

Virus discovery in cultured portunid crabs: Genomic, phylogenetic, histopathological and microscopic characterization of a reovirus and a new bunyavirus

Portunid crabs are distributed worldwide and highly valued in aquaculture. Viral infections are the main limiting factor for the survival of these animals and, consequently, for the success of commercial-scale cultivation. However, there is still a lack of knowledge about the viruses that infect cultured portunid crabs worldwide. Herein, the genome sequence and phylogeny of Callinectes sapidus reovirus 2 (CsRV2) are described, and the discovery of a new bunyavirus in Callinectes danae cultured in southern Brazil is reported. The CsRV2 genome sequence consists of 12 dsRNA segments (20,909 nt) encode 13 proteins. The predicted RNA-dependent RNA polymerase (RdRp) shows a high level of similarity with that of Eriocheir sinensis reovirus 905, suggesting that CsRV2 belongs to the genus Cardoreovirus. The CsRV2 particles are icosahedral, measuring approximately 65 nm in diameter, and exhibit typical non-turreted reovirus morphology. High throughput sequencing data revealed the presence of an additional putative virus genome similar to bunyavirus, called Callinectes danae Portunibunyavirus 1 (CdPBV1). The CdPBV1 genome is tripartite, consisting of 6,654 nt, 3,120 nt and 1,656 nt single-stranded RNA segments that each encode a single protein. Each segment has a high identity with European shore crab virus 1, suggesting that CdPBV1 is a new representative of the family Cruliviridae. The putative spherical particles of CdPBV1 measure ∼120 nm in diameter and present a typical bunyavirus morphology. The results of the histopathological analysis suggest that these new viruses can affect the health and, consequently, the survival of C. danae in captivity. Therefore, the findings reported here should be used to improve prophylactic and pathogen control practices and contribute to the development and optimization of the production of soft-shell crabs on a commercial scale in Brazil.

A new portunid crab (Brachyura, Portunoidea) from the upper Middle Miocene of Sardinia, Italy

A new portunid crab (Brachyura, Portunoidea) from the upper Middle Miocene of Sardinia, Italy

Abundance and Distribution of Blue Swimmer Crab in Response to Environmental Variation Across Two Contrasting Estuaries

Portunid crabs are an iconic, high value species in NSW, but catches are highly variable in space and time. Substantial variation in biomass is observed in both exploited and unfished populations, and environmental effects on distribution and abundance are an important factor contributing to this variability. Predicting and responding to this variability is a challenge for management and sustainability of exploited populations. We examine spatial and temporal variation in Blue Swimmer Crab (Portunus armatus) populations, over a 2.5 year trapping survey in two temperate estuaries that differ in tidal flow and riverine input. Specifically, monthly catch rates and distribution throughout the estuary are examined alongside variation in temperature and conductivity. In Wallis Lake, the shallower estuary with a restricted entrance, both water temperature and conductivity impacted abundance and distribution of crabs but there was no evidence that pulses of freshwater flow had a major impact. For a 10 °C increase in temperature the population on average shifted ~ 700 m closer to the ocean. Males were consistently located slightly further into the estuary compared to females, but there was no convincing evidence of estuarine egression in response to lower salinity. In Port Stephens, the deeper, tidal estuary, water temperature and conductivity also impacted abundance, but while males were more dispersed than females, the distribution of crabs within the estuary did not appear to be influenced by temperature, conductivity or flow. These results highlight the links between nuanced environmental relationships and estuarine geomorphology for Blue Swimmer Crab.

Climate change enables invasion of the portunid crab Charybdis bimaculata into the southern Bohai Sea

In May 2020, a bottom-trawl survey in the southern Bohai Sea collected the portunid crab Charybdis bimaculata, a species formerly found in the northern Yellow Sea. In subsequent surveys, C. bimaculata was found to be abundant and likely to occupy habitats and niches of native species. To study the suitability of habitat in the southern Bohai Sea for this crab, nine trawl surveys were conducted between 2020 and 2022 to monitor its dispersal. Using Biomod2 software and combining species occurrence and environmental data, a distribution model for C. bimaculata in the southern Bohai Sea is developed. We analyze relationships between this and other crustacean species by comparing niche widths and their overlap. A random forest model outperforms eight others, and has the highest evaluation indices among single algorithm species-distribution models. The evaluation index of an ensemble model is significantly higher than those of single algorithm models, indicating its greater accuracy and robustness. We report suitable habitat for C. bimaculata to occur mainly in central and northeastern Laizhou Bay, and for this habitat suitability to shift over years from the middle to northeastern waters. Niche width showed a negative trend from 2020 to 2022, and is greater in May than August for each year. Niche overlaps between C. bimaculata and other major crustaceans in the southern Bohai Sea exist. We consider that increased sea surface temperature caused by climate change enabled invasion of C. bimaculata from northern Yellow Sea waters into the southern Bohai Sea, where it can overwinter and complete its life cycle. These results provide a scientific basis upon which monitoring of C. bimaculata in the Bohai Sea can be strengthened to better cope with its invasion and any negative impact on local biodiversity.

Carapace Length–Weight, Carapace Width–Weight Relationships and Relative Condition Factor of Four Portunid Crab Species of the Gulf of Mannar, Southeast Coast of India

Carapace Length–Weight, Carapace Width–Weight Relationships and Relative Condition Factor of Four Portunid Crab Species of the Gulf of Mannar, Southeast Coast of India

Altering river flow impacts estuarine species and catches: lessons from giant mud crabs

Abstract Anthropogenic alterations to river flow could have repercussions for flow-dependent species downstream but few studies account for these dynamic relationships or quantify impacts of altered river flow. Scylla serrata—a widely distributed portunid crab—was used as an example of a flow-dependent species to model impacts of altered flow on species abundance and catch. Crab population dynamics were modelled across a large semi-enclosed tropical sea in northern Australia. Environmental drivers, primarily river flow, but also temperature and the Southern Oscillation Index were linked to crab dynamics to explain variability in historical catches. Catch and abundance could then be predicted under altered flow scenarios. River flow significantly improved the ability to explain historical catches for some regions but not all, and the strength of this relationship varied across catchments. Altered flows had negligible effects for perennial rivers but for ephemeral and temporally variable rivers, predicted decreases in abundance and catch ranged from 36 to 46% on average. Our modelling approach showcases a way to dynamically and rigorously quantify impacts of altered river flow on a key species with potential to help inform natural resource management, including policy decisions on the timing, quantity, and method of water removed from rivers.

Tropical estuarine ecosystem change under the interacting influences of future climate and ecosystem restoration.

One of the largest restoration programs in the world, the Comprehensive Everglades Restoration Plan (CERP) aims to restore freshwater inputs to Everglades wetlands and the Florida Bay estuary. This study predicted how the Florida Bay ecosystem may respond to hydrological restoration from CERP within the context of contemporary projected impacts of sea-level rise (SLR) and increased future temperatures. A spatial-temporal dynamic model (Ecospace) was used to develop a spatiotemporal food web model incorporating environmental drivers of salinity, salinity variation, temperature, depth, distance to mangrove, and seagrass abundance and was used to predict responses of biomass, fisheries catch, and ecosystem resilience between current and future conditions. Changes in biomass between the current and future scenario suggest a suite of winners and losers, with many estuarine species increasing in both total biomass and spatial distribution. Notable biomass increases were predicted for important forage species, including bay anchovy (+32%), hardhead halfbeak (+19%), and pinfish (+31%), while decreases were predicted in mullet (-88%), clupeids (-55%), hardhead silverside (-15%), mojarras (-117%), and Portunid crabs (-16%). Increases in sportfish biomass included the angler-preferred spotted seatrout (+9%), red drum (+10%), and gray snapper (+8%), while decreases included sheepshead (-40%), Atlantic tarpon (-73%), and common snook (-507%). Ecosystem resilience and fisheries catch of angler-preferred species were predicted to improve in the future scenario in total, although a localized decline in resilience predicted for the Central Region may warrant further attention. Our results suggest the Florida Bay ecosystem is likely to achieve restoration benefits in spite of, and in some cases facilitated by, the projected future impacts from climate change due to the system's shallow depth and detrital dominance. The incorporation of climate impacts into long-term restoration planning using ecosystem modeling in similar systems facing unknown futures of SLR, warming seas, and shifting species distributions is recommended.

Gene flow with the help of sea turtles: phylogeography of the epibiont barnacleChelonibia testudinaria(Linnaeus, 1758) (Crustacea: Cirripedia: Chelonibiidae) from the Persian Gulf

AbstractChelonibia testudinaria (Linnaeus, 1758) is a globally distributed epibiont barnacle using different hosts, including sea turtles and portunid crabs. Previous phylogenetic analyses have recovered three distinct clades for this species corresponding to the Atlantic, Eastern Pacific, and Indo-West Pacific regions. The present study of the genetic diversity of this species in the Persian Gulf (northwestern Indian Ocean) using the COX1 mitochondrial marker estimates the genetic connectivity of the barnacle between the Persian Gulf and two western Pacific regions. No significant genetic differentiation is evident between the Persian Gulf and the western Pacific, but the moderate level of genetic connectivity found between these areas across the Indian Ocean is likely mediated by migratory sea turtles. Based on the present analysis, the Persian Gulf displays a lower genetic diversity than the diversity of the western Pacific populations but shares some haplotypes with the latter.

Is the population increase of an invasive portunid crab (Charbydis hellerii) a concern? The effect on native prey

Biological invasions have the potential to change the local marine biodiversity through increasing predation pressure and interactions among species. Charybdis hellerii is a swimming crab native to the Indo-West Pacific, it was first collected in the Atlantic Ocean in 1987 and is currently found in high abundance in coastal areas of southeastern Brazil. We evaluated the presence of the invasive crab C. hellerii from the coast of São Paulo state, Brazil, analyzing the stomach contents and performing laboratory-based feeding experiments. In crabs with stomachs full enough to be analyzed (N = 19), mussels (30%) and brachyuran crabs (14.21%) were the most frequent prey items found. Based on these data, we experimentally tested how different densities and life stages (adults and juveniles - differentiated by carapace width - CW) of the invasive crab affected feeding patterns. Results indicated that predator density effects on the predation pressure were dependent on the prey type. Mussels were consumed highest at medium predator densities (30 crabs/m3), whereas crabs were consumed highest at high predator densities (60 crabs/m3). There was no influence of the life stage on prey consumption, suggesting that adults (CW = 57.12–67.59 mm) and juveniles (CW = 39.77–43.18 mm) exhibit similar predation. Charybdis hellerii is an important consumer of benthic native prey, having the potential to change food webs through predation pressure on bioengineers and associated fauna. As the removal of C. hellerii from the environment is difficult, the next step toward is to understand the effect of the invasive crab on the native trophic web.

Recruitment and growth patterns of the portunid crab Charybdis bimaculata in Kagoshima Bay, southern Japan

Recruitment and growth patterns of the portunid crab Charybdis bimaculata in Kagoshima Bay, southern Japan

Long-term drivers of catch variability in south-eastern Australia’s largest portunid fishery

Portunid crab fisheries are socially and economically valuable yet are characterised by high inter-annual variability. Competing hypotheses about factors contributing to this variability concern the environment, climate, and fisher behaviour. Here, we investigate variability in commercial catch, through a case study of the most heavily exploited estuary in southeastern Australia (Wallis Lake). Four main hypotheses were identified based on the broader portunid published literature: 1) Freshwater flow may cause poor recruitment due to increased offshore spawning and unfavourable dispersal of larvae, 2) Winter and spring harvesting may impact the following summer harvest by removing the spawning stock biomass (recruit overfishing); 3) Environmental factors including sea surface temperature and onshore winds may influence supply-side processes and recruitment success, contributing to catch fluctuations; and 4) Climatic indices such as the Inter Pacific Oscillation and Pacific Decadal Oscillation (PDO) may correlate with longer-term fluctuations in the fishery. We find evidence in support of hypotheses 2 and 4, with winter harvest negatively impacting the following January - April harvest and the PDO being positively correlated with January - April catch rates. Harvesting in June – November disproportionally impacts large females, and it may be possible to incorporate controls on winter fishing effort through co-management arrangements to achieve the best economic, environmental and social outcomes from the fishery. Such controls may lead to improved summer catch rates by protecting unspawned eggs during the winter months. The hypotheses explored here may provide insight in the variability observed in portunid fisheries around the world.

Resolving Species Delineation of Four Portunid Crab Species of the Gulf of Mannar using Truss Morphometry

Resolving Species Delineation of Four Portunid Crab Species of the Gulf of Mannar using Truss Morphometry

The Effects of Environmental Variables and Morphometry on Hemocyte Structure in the Hemolymph of Portunid Crab, Carcinus aestuarii Nardo, 1847 in Çardak Lagoon (Çanakkale Strait)

This study aims to determine the relationship between hemocyte count and hemocyte types with environmental variables and morphometric measurements in Carcinus aestuarii. A total of 240 crabs were seasonally collected in Çardak Lagoon June 2018, October 2018, February 2019, and May 2019. The average carapace length (CL) was 44.66±0.44 mm, the mean carapace width (CW) was 37.71±0.38 mm and the mean weight was 28.49±0.88 g. Crab specimens were anesthetized on ice for 10 min, and 500 µL of hemolymph was collected from the legs of each crab using a 1-mL plastic syringe. After sampling, hemolymph samples were mixed with the anticoagulant, which was applied to a Thoma slide and examined under a microscope at X40 magnification. The total hemocyte count (THC) was calculated as 13.91±8.08x106 (cells/mm3). Differential hemocyte count (DHC) 53.25±0.6% for hyalinocyte, 26.15±0.23% for semi-granulocyte, and 20.6±0.06% for granulocyte and 3 different cell types were observed. The most dominant cell type is hyalinocyte cells.

Mesoscale oceanographic features drive divergent patterns in connectivity for co‐occurring estuarine portunid crabs

AbstractLarval dispersal and connectivity have important implications for fisheries management, especially for species with life cycles influenced by ocean boundary currents. Giant Mud Crab (Scylla serrata) and Blue Swimmer Crab (Portunus armatus) are two estuarine portunid crabs (Family: Portunidae) that support significant commercial and recreational harvest in eastern Australia. Giant Mud Crab migrate to coastal waters to spawn, and while Blue Swimmer Crab spawn primarily within estuaries they occasionally migrate to coastal waters to spawn, followed by larval dispersal in the East Australian Current (EAC). Here, we coupled a high‐resolution oceanographic model with a Lagrangian particle tracking framework to simulate larval dispersal and determine the extent of population connectivity in this region. Our simulations indicate broad‐scale connectivity (~40–400 km), characterised by high inter‐estuary connectivity. Overall, our results suggest a north‐to‐south source‐sink structure for both species, with contributions of particles from the north ranging from 51% to 99%. Recruitment to a given estuary is dependent on the proximity of mesoscale oceanographic features of the EAC. Most notably, the EAC separation acts as a barrier to recruitment between spawning and settlement to the north/south of this region. This significantly limits interjurisdictional connectivity for these species, especially Blue Swimmer Crab, likely due to a shorter pelagic larval duration than Giant Mud Crab. Our results provide evidence to inform the assessment and management of these species.

New Alien Mediterranean Biodiversity Records (August 2022)

In this Collective Article on alien and cryptogenic diversity in the Mediterranean Sea we report a total of 19 species belonging to nine Phyla and coming from nine countries. Several of these records concern fish species, and of particular interest are the first records of: Terapon puta for Italian waters; Pteragopus trispilus from Malta; Plotosus lineatus from Cyprus; and the northernmost Mediterranean record of Lagocephalus sceleratus. The northernmost Mediterranean record was also reported for the sea urchin Diadema setosum. The portunid crab Thalamita poissonii was recorded for the first time in Libya. The copepod Pseudodiaptomus marinus was recorded for the first time in the Marmara Sea. The polychaete Branchiomma luctuosum was recorded for the first time from the Mediterranean coast of France. The alien anemone Diadumene lineata was recorded for the first time from Slovenia. The macroalgae Sargassum furcatum was recorded for the first time from Italy. The new Mediterranean records here reported help tracing abundance and distribution of alien and cryptic species in the Mediterranean Sea.

Transcriptomic analysis of male three-spot swimming crab (Portunus sanguinolentus) infected with the parasitic barnacle Diplothylacus sinensis

Diplothylacus sinensis is reported as an intriguing parasitic barnacle that can negatively affect the growth, molting, reproduction in several commercially important portunid crabs. To better understand the molecular mechanisms of host-parasite interactions, we characterized the gene expression profiles from the healthy and D. sinensis infected Portunus sanguinolentus by high-through sequence method. Totally, the transcriptomic analysis generated 52, 266, 600 and 51, 629, 604 high quality reads from the infected and control groups, respectively. The clean reads were assembled to 90,740 and 69,314 unigenes, with the average length of 760 bp and 709 bp, respectively. The expression analysis showed that 18,959 genes were significantly changed by the parasitism of D. sinensis, including 4769 activated genes and 14,190 suppressed genes. The differentially expressed genes were categorized into 258 KEGG pathways and 647 GO terms. The GO analysis mapped 13 DEGs related to immune system process and 32 DEGs related to immune response, respectively, suggesting a potential alteration of transcriptional expression patterns in complement cascades of P. sanguinolentus. Additionally, 4 representative molting-related genes were down-regulated in parasitized group, indicating D. sinensis infection appeared to suppress the producing of ecdysteroid hormones. In conclusion, the present study improves our understanding on parasite-host interaction mechanisms, which focuses the function of Ecdysone receptor, Toll-like receptor and cytokine receptor of crustacean crabs infestation with rhizocephalan parasites.

Diet of the bonnethead (Sphyrna tiburo) along the northern Gulf of Mexico and southeastern Atlantic coast of the United States

The diet of a potentially omnivorous coastal shark species, the bonnethead (Sphyrna tiburo), was examined in the western Atlantic along the coast of the southeastern United States. A total of 423 stomachs collected from Texas, Alabama, Florida and South Carolina were analyzed using standardized stomach content analysis methods. The diet was dominated by crabs, primarily portunids (Callinectes spp.), across the geographical range analyzed, though the relative importance of crabs varied between regions. Ontogenetic shifts in diet were not observed throughout the region studied. Female and male bonnetheads in South Carolina displayed different diets, particularly in the amount of portunid crabs consumed, with a higher proportion ingested by females. Bonnetheads consumed limited amounts of seagrasses in all regions except in South Carolina, where they occupy habitats without seagrasses in marsh dominated bays and estuaries. This finding indicates that, at least seasonally, seagrasses are not an essential part of the diet of this shark species and may only occur in stomachs as accidental ingestion.

Transcriptomics in advancing portunid aquaculture: A systematic review

AbstractThe rapid advancement of next‐generation sequencing technologies has promoted the use of transcriptomics in non‐model organisms, including species in the aquaculture sector. Compared to that of other crustacean species, portunid crab aquaculture is impeded by the insufficient knowledge of their biological and physiological processes. This systematic review summarised the advances in transcriptomics in cultured portunid crabs using a systematic literature review methodology. The filtered transcriptome dataset comprised 66 articles from four genera: Scylla, Portunus, Callinectes and Charybdis. At the species level, Scylla paramamosain and Portunus trituberculatus were the two most studied species, highlighting their importance in the aquaculture sector. The affordable cost of RNA sequencing (RNA‐Seq) led to an increase in transcriptome‐related research in portunid crabs and made available a huge repertoire of differentially expressed genes (DEGs) and single nucleotide polymorphisms (SNPs). We further discussed the transcriptomic advances based on six main functional categories, that is, ‘growth and moulting’, ‘gonadal development and reproduction’, ‘nutrition metabolism’, ‘disease and immunity’, ‘toxicology and stress’ and ‘general transcriptomic profiling’. In general, transcriptomic studies of portunid crabs, specifically the DEGs and pathways allow an in‐depth understanding of the biological and physiological processes involved at different growth stages or under various conditions based on the difference in gene transcriptional activity. SNPs obtained from the transcriptome data are useful in many genetic improvement‐related downstream applications, including the construction of genetic linkage maps and as population genetic markers. Future directions, such as hybrid approaches of long‐read and common RNA‐Seq, and the incorporation of other omics were also discussed.