Swimming Crab Charybdis Research Articles

A host, a parasite, and a predator: the dynamics of successive invasions in the eastern Mediterranean

The eastern Mediterranean shelf ecosystem has been profoundly disrupted by the influx of invasive alien species introduced through the Suez Canal. Yet, the role of retaining or shedding co-evolved parasitofauna in the success of the invading biota has been scarcely monitored, with the exception of the lesser swimming crab Charybdis (Archias) longicollis Leene, 1938 parasitized by the rhizocephalan Heterosaccus dollfusi Boschma, 1960. Host size, sex ratio, prevalence of ovigerous females, parasitization, and multiple parasitization, were studied over 30 years to determine long-term host-parasite variation. Our results reveal that C. longicollis crabs have shifted their temporal activity pattern shortly following the domination of their preferred depth niche by the invasive diurnal predator, the silver-cheeked toadfish Lagocephalus sceleratus (Gmelin, 1789), which preferentially feeds on C. longicollis locally. A unique set of predator-host-parasite interactions among three successive Erythraean invasive aliens is considered herein.

Population structure and reproductive dynamics of the ridged swimming crab Charybdis natator in the southern Taiwan Strait of China: significant changes within 25 years

The ridged swimming crab Charybdis natator (Portunidae) is a commercially important crustacean species in China. The purpose of this study is to compare its population structure and reproductive pattern within the same fishing area (the southern Taiwan Strait) from two datasets over 25 years; one from 1994−1996 (the early years of the C. natator fishery) and the other from 2019. The overall sex ratio (male:female) changed from a male bias (1:0.76, p < 0.01) in 1994−1996 to a female bias (1:1.38, p < 0.01) in 2019. Male body sizes (carapace width, CW) were significantly larger than those of females in both datasets (p < 0.05). The average CW and body weight (BW) of males and females in 2019 were significantly smaller (p < 0.01) and lighter (p < 0.01) than those in 1994−1996. The maximum body size and the proportion of large-sized individuals (CW > 10 cm) decreased dramatically over 25 years. One spawning peak season was identified from each dataset, i.e., March−August 1994−1996 and February−April 2019, revealing a 1-month shift. The minimum body sizes for female maturation (carrying eggs) were 6.9 cm CW in 1994−1996 and 6.1 cm CW in 2019, an 11.6% reduction over 25 years. For the first time, the CW at 50% female maturation, the relationship between female absolute fecundity and CW, and egg diameters were obtained from the 2019 dataset, which can be applied in the future comparisons. Recent studies have revealed a consistent spawning peak in February–April for several commercially important crabs in the southern Taiwan Strait. These findings should be considered in crab fishery management. Furthermore, both fishery- and environment-associated factors influencing crustacean population structure and reproductive dynamics merit further investigation.

Investigations on depredation by the deepsea swimming crab Charybdis smithii, during experimental gillnetting along the south-west coast of India

Depredation by crabs can have a negative impact on marine gillnet fishery. Despite this fact, limited studies are attempted to evaluate depredation. The present study is the first attempt to evaluate the qualitative and quantitative effects of crab depredation on marine gillnet fishery. Experimental gillnetting was conducted onboard F V Sagar Harita from February 2017 to January 2018 along the south-west Indian coast. Depredation by the deepsea swimming crab Charybdis smithii caused intentional discard of Indian mackerel (17.59%), kawakawa (14.77%), shrimp scad (10.74%) and horse mackerel (10.02%). Financial loss due to depredation was high for Indian mackerel (19.99%), followed by shrimp scad (19.17%), kawakawa (14.77%) and horse mackerel (14.16%). A total of ₹2554.30 per operation was lost due to crab depredation. C. smithii showed a preference towards scombrids (Indian mackerel and kawakawa) over carangids (shrimp scad and horse mackerel) due to the inherent flavour and texture of scombrids. Incidence of depredation were found exclusively during June to September (monsoon season). Keywords: Crab, Depredation, Economic loss, Fishery, Marine gillnet

First report of the invasive swimming crab Charybdis hellerii (A. Milne-Edwards, 1867) (Decapoda, Portunidae) near the Great Amazon Reef System, Amapá, Brazil

In this paper, we report for the first time the occurrence of the swimming crab Charybdis hellerii (A. Milne-Edwards, 1867) on the continental shelf of Amapá State. Four specimens were collected as bycatch fauna during industrial fishing operations targeting the southern brown shrimp. The specimens have been deposited in the Carcinological Collection of the Centro Nacional de Pesquisa e Conservação da Biodiversidade Marinha do Norte — ICMBio/CEPNOR. The occurrence fills a knowledge gap about the distribution of the species in the northern Brazilian coast since the species was recorded in French Guyana and in the northern to southeastern regions of Brazil. Primeiro registro do siri invasor Charybdis hellerii (A. Milne-Edwards, 1867) (Decapoda, Portunidae) próximo ao Grande Sistema de Recifes da Amazônia. Neste trabalho, relatamos pela primeira vez a ocorrência do siri Charybdis hellerii (A. Milne-Edwards, 1867) na plataforma continental do estado do Amapá. Foram coletados quatro exemplares como fauna acompanhante em operações de pesca industrial do camarão-rosa. Os exemplares estão depositados na Coleção Carcinológica do Centro Na-cional de Pesquisa e Conservação da Biodiversidade Marinha do Norte — ICMBio/CEPNOR. A ocorrência preenche uma lacuna de conhecimento sobre a distribuição da espécie no lito-ral norte brasileiro, uma vez que a espécie foi registrada na Guiana Francesa e nas regiões de Norte ao Sul do Brasil.

Growth and reproduction of the two-spot swimming crab Charybdis bimaculata (Miers, 1886) (Decapoda, Brachyura) in Goheung Bay, Korea

Abstract The growth and reproduction of Charybdis bimaculata (Miers, 1886) were investigated in Goheung Bay, Korea, from February 2020 to February 2021. Females were observed more frequently than males. The gonadosomatic index varied monthly, and reached the highest value in July. Ovigerous females peaked in July as well. The main spawning season was summer. The size at sexual maturity of females, corresponding to a proportion of 0.5 sexually mature individuals, was estimated as 20.93 mm carapace width (CW). The relationship between ln number of eggs (EN) and was for noneyed eggs, and for eyed eggs. Males grew faster than females ( mm CW and year−1 for males, and mm CW and year−1 for females).

Effects of the swimming crab Charybdis japonica on sea urchin Mesocentrotus nudus grazing: cage experiments in barren ground and land-based tanks

Effects of the swimming crab Charybdis japonica on sea urchin Mesocentrotus nudus grazing: cage experiments in barren ground and land-based tanks

Extraction and Characterization of Chitin and Chitosan from Invasive Alien Swimming Crab Charybdis longicollis

Chitosan is a biocompatible, biodegradable, non-toxic, antibacterial, antioxidant, and antifungal natural polymer. In this study, chitin and chitosan were chemically isolated from the exoskeleton of invasive swimming crab Charybdis longicollis. In order to obtain the chitin, demineralization, deproteinization, and decolourization steps were applied to the samples. Chitosan was prepared from the isolated chitin by deacetylation at high temperatures. The chemical composition of chitin from C. longicollis was characterized by XRD and FTIR analysis. The yield of chitin extraction from dry crab shells was 25.78 %. The yield of chitosan produced from extracted chitin was 80.23 %. The experimental analyses revealed that the obtained chitin and chitosan could be used as biomaterial.

Predation on the invasive swimming crab Charybdis hellerii (Crustacea, Decapoda) by Myrichthys ocellatus (Actinopterygii, Ophichthidae): the first record of consumption by a native fish

ABSTRACT Charybdis hellerii is an invasive swimming crab widely disseminated in the western Atlantic. This species became a threat to colonized ecosystems, competing with local species for resources. The extension of distribution and increasing population size of C. hellerii has been associated with the scarcity of indigenous predators and cases of predation report octopuses as the main native predators. In this study, we present the first evidence that native fish can consume C. hellerii. 53 individuals of the goldspotted snake eel, Myrichthys ocellatus, were collected at seagrass and macroalgal beds in Pernambuco State, Brazil, and had their stomach contents analyzed. Three juvenile C. hellerii were found along with native prey. Myrichthys ocellatus feeds mainly on small crabs, thus C. hellerii individuals were consumed before reaching sexual maturity. Oppositely to octopuses and other crab predators, M. ocellatus is of little fishing interest and is commonly found in macroalgae beds, seagrass meadows and sandy areas near reefs. Our results suggest that a higher number of carcinophagous taxa may prey on this invasive crab and we emphasize that the conservation of these species is paramount for controlling C. hellerii populations in invaded areas.

Risk screening of the potential invasiveness of non-native marine crustacean decapods and barnacles in the Mediterranean Sea

Non-native marine crustaceans can exert detrimental impacts on native marine communities by altering habitat and ecosystem function. The Mediterranean Sea is particularly vulnerable to introductions of non-native crustaceans, as evidenced by their remarkably high establishment success. In this study, 20 species of non-native marine crustacean decapods and barnacles of which eleven extant and nine ‘horizon’ were screened for their potential invasiveness in the Mediterranean Sea. Using the Aquatic Species Invasiveness Screening Kit and including an additional nine native species to increase accuracy, calibrated risk thresholds of 3.5 for the BRA (Basic Risk Assessment) and 8.5 for the BRA + CCA (BRA + Climate Change Assessment) were obtained that distinguished reliably between invasive and non-invasive species. All 20 non-native species were classified as carrying a high risk of invasiveness for the Mediterranean Sea, both for the BRA and the BRA + CCA. Chinese mitten crab Eriocheir sinensis was by far the highest risk species, followed by Harris mud crab Rhithropanopeus harrisii, Asian shore crab Hemigrapsus sanguineus, bay barnacle, Amphibalanus improvisus, and lesser swimming crab Charybdis (Goniohellenus) longicollis. The findings of this study will provide management and control directions for non-native marine crustaceans in the Mediterranean Sea, with special emphasis on regulations regarding ballast waters, which represent one of the main introduction pathways for these aquatic organisms.

Effects of the trap entrance designs on the catch efficiency of swimming crab Charybdis feriata fishery

The swimming crab Charybdis feriata fishery is important to the coastal fishing communities of Vietnam, particularly in the province of Quang Nam. Trapping is considered a low impact and fuel-efficient fisheries capture technique that is drawing increasing attention as concerns regarding the impact of fisheries on ecosystems and the environment grow. However, traps typically have low capture efficiency for most crab species and there is considerable interest to improve catchability. In this study we investigated the impact of modifying the number of trap entrances on a traditional trap design, and also the colour of entrance-netting, on the catch rate of swimming crab in the Vietnam trap fishery. In the first experiment we compared catch rates between a traditional three-entrance trap and a modified one-entrance trap design, and found that the modified one-entrance trap had a 24 % higher catch rate. In second experiment, we compared catch rates of one-entrance traps having green or yellow entrance-netting and found that yellow netting increased catch rates by 31 %. This study shows that fishing enterprises could improve their swimming crab trap fishery by using modified one-entrance traps with yellow entrance netting.

Composition and catch rate of folded cube fish pots in the sea of Tuban Regency

This study aimed to determine the composition and catch rate of folded cube fish pots in the seawater of the Tuban Regency. The research was conducted in December 2018 located in the Sokorejo, Tuban Regency, using 30 units of folded cube fish pots with a size of 50x50x50 cm2. The cube folded trap installation was done in 10 times of catch trip and installed in the morning. The catches were collected, identified, and measured for their individual length and weight. The crabs were measured for the length and width of their carapace. The catching result of folded cube fish pots was classified into five types which are fish group (48.97%), crabs group (29.59 %), swimmer crabs (7.1%), Land hermit crab (6.12%), and mud snails (8.16%). The result showed that Two-spined Arm Swimming Crab (Charybdis anisodon) was the most dominant type of catch equal to 29.59% of the total catch, while other types of catch that were quite common are Pig Faced Leather Jacket (Paramonacanthus choirocephalus) (9.18%), and Crescent Pearch (Terapon jarbua) (8.16%). The average catch rate for folding cube was 32%/trip with a weighted average catch of 436.58 gr/trip.

Nutritional Evaluation of Indian Ocean Swimming Crab, Charybdis smithii (Portunidae), an Unconventional Crab Resource from the Indian Coast

ABSTRACTInvestigations were carried out to determine the nutritional profile of Indian Ocean swimming crab Charybdis smithii, which is emerging as an unconventional resource in trawl discards of India. The average protein content was 9.38 g/100 g, fat 0.86 g/100 g, ash 0.34 g/100 g, fiber 0.13 g/100 g, and carbohydrate 1.8 g/100 g. One-way analysis of variance showed no significant variations of constituents except in dry matter and carbohydrate between sexes. Macronutrients, Na (317.1, 327.6/100 g), K (148, 177.40 mg/100 g), Ca (187.90, 285.80 mg/100 g), and Mg (34.31, 41.49 mg/100 g), showed significant variation between sexes. The composition of micronutrients in male and female were Cu (0.28, 0.15 mg/100 g), Fe (0.57, 0.71 mg/100 g), and Zn (1.71, 2.75 mg/100 g). Mineral content showed significant difference between sexes. Amino acid analysis showed that 12.04 and 11.47 g/100 g essential amino acid glycine was present in male and female, respectively, and lysine concentration was 13.96 and 12.65 g/100 g, respectively. The nutritional profile of the species was determined the first time and shows that it is comparable with any other edible crabs and could be exploited as a commercial resource to supplement nutritional demand.

Use of osmoregulatory ability to predict invasiveness of the Indo-Pacific swimming crab Charybdis hellerii (A. Milne-Edwards, 1867) an invader in Southern Brazil

Use of osmoregulatory ability to predict invasiveness of the Indo-Pacific swimming crab Charybdis hellerii (A. Milne-Edwards, 1867) an invader in Southern Brazil

Characterization of complete mitochondrial genome of two-spot swimming crab Charybdis bimaculata (Miers, 1886)

The two-spot swimming crab Charybdis bimaculata (Miers, 1886) is an important decapod species in the benthic ecosystem of Korean waters. In this study, we determined its complete mitochondrial genome by the combination of NGS analysis using MiSeq platform and PCR-based cloning method. The circular mitochondrial genome of C. bimaculata was 15,714 bp in length in which the standard set of 13 protein-coding genes, 22 tRNA genes, and 2 rRNA genes were encoded. Phylogenic analysis showed that C.bimaculata is most closely related to Charybdis feriata. The complete mitogenome sequence information of C. bimaculata would provide useful data for the conservation of their population in the Pacific ocean.

Tracing the introduction history of the invasive swimming crab Charybdis hellerii (A. Milne-Edwards, 1867) in the Western Atlantic: evidences of high genetic diversity and multiple introductions

The swimming crab Charybdis hellerii is an invader with global distribution in warm waters. Native to the Indo-Pacific, this species invaded the eastern Mediterranean Sea after the Suez Canal opening. In 1987, it was first reported in the Western Atlantic, probably transported via ballast water of ships. Since then, it has been registered from many localities along the American coast from the USA to southern Brazil where it has rapidly established reproducing populations. Our main aim was to investigate the introduction history of this species along the American coast, using a phylogeographic approach. Additionally, we attempted to clarify the identity of this invasive species by molecular analyses and morphological assessment in order to provide a basis for our main investigation. C. hellerii was confirmed as a single species, but both cytochrome c oxidase subunit I and 16S rDNA revealed a genetic structure, splitting the potential source populations of American introductions into two groups: “western Indian Ocean and Mediterranean Sea” (WIO + MS) versus “eastern Indian + western Pacific oceans” (EIO + WPO). Most specimens from America clustered with the former group, supporting the hypothesis that the Mediterranean Sea represented the main source of Western Atlantic populations. However, the clustering of animals from southern Brazil with the latter group indicates that introductions from the eastern Indian or Pacific oceans must also have occurred. The existence of a third group, found exclusively within the American range and genetically related to EIO + WPO, also indicates an independent introduction from an unsampled locality from the native range. The haplotype and nucleotide diversities of American localities were comparable to those of source populations, contradicting a founder effect prediction. This finding might be related to the high propagule pressure associated with introductions via ballast water and the occurrence of multiple introductions from genetic distinct sources. The direct comparison of the haplotype numbers suggested no genetic bottleneck during introduction from the Mediterranean Sea, but a bottleneck might have occurred during introductions from the eastern Indian or Pacific oceans.

The complete mitochondrial genome of the swimming crab Charybdis natator (Herbst) (Decapoda: Brachyura: Portunidae) and its phylogeny

The complete mitochondrial genome of Charybdis natator (family Portunidae) was obtained using Illumina and Sanger dideoxy sequencing. This genome was a typically circular molecule with a length of 15,664 bp and encoded 13 protein-coding genes, 22 transfer RNA genes and 2 ribosomal RNA genes. The overall base composition of this mitogenome was 34.00% for A, 11.06% for G, 36.36% for T, and 18.58% for C, respectively, with a higher A + T content (70.36%). The gene composition and arrangement were accordant to the closely published species. The phylogenetic analysis suggested that C. natator had the closest relationship with C. japonica.

Mitochondrial prohibitin and its ubiquitination during spermatogenesis of the swimming crab Charybdis japonica

It has been proposed that prohibitin (PHB) involved in multiple cellular functions, including cell proliferation, differentiation, apoptosis, senescence and carcinogenesis. Various cellular compartment location of PHB demonstrates its diverse roles. Based on the full-length sequence of PHB gene, we analyzed the deduced amino acid sequence and the predicted protein structure of this gene in the swimming crab Charybdis japonica. It shows that the structure and function of PHB are conservative. The expression level of PHB mRNA and protein in different tissues were analyzed by sqRT-PCR and western blot respectively, which showed its high expression in testis. We then traced PHB protein by immunofluorescence, and we found its diverse distribution in cytoplasm and mitochondria at different stages. We propose that PHB may participate actively in spermatogenic cell anti-apoptosis, cell nucleus distortion as well as acrosome morphogenesis during the spermatogenesis in Charybdis japonica. Furthermore, PHB was found to be ubiquitinated at different levels. Its signal was weak in spermatocytes and Stage 1 spermatids, stronger in stage 2–4 spermatids, and lowest in mature sperm. Our data shows that PHB may mediate the paternal mitochondrial material degradation by ubiquitination. We conclude that PHB is indispensable in the spermatogenesis of the swimming crab Charybdis japonica through different testis developmental stages.

Going down together: invasive host, Charybdis longicollis (Decapoda: Brachyura: Portunidae) and invasive parasite, Heterosaccus dollfusi (Cirripedia: Rhizocephala: Sacculinidae) on the upper slope off the Mediterranean coast of Israel

ABSTRACTThe swimming crab Charybdis longicollis, native to the western Indian Ocean, was first recorded in the Mediterranean in 1954. It is now established from Egypt to Greece, and dominates the sandy-mud bottoms at 25–80 m in the southeastern Mediterranean. The success of C. longicollis is attributed to its high fecundity, agonistic behaviour and omnivorous diet, as well as the rise in seawater temperature. Since the early 1990s its populations in Israel and Turkey have been heavily parasitized by the alien rhizocephalan Heterosaccus dollfusi, which impacts its host’s behaviour, growth and fecundity, and causes mortality. Yet, 60 years after its first record in the Mediterranean, the population of C. longicollis seems durable, and has recently spread to the lower shelf and upper slope off Israel, where it is common at 80 m and is found down to 250 m, greatly increasing its spatial spread. The maximal percentage of parasitization was 87.2%, 88.8%, 75.5% and 81.8% at depths of 40, 60, 80, 100 m, respectively, and 50% at 120 and 250 m. Here, we hypothesize on the possible contribution of the depletion of its putative fish predators, mainly rays, to the prevalence of C. longicollis on the lower shelf.

First record of the invasive swimming crab Charybdis hellerii (A. Milne Edwards, 1867) (Crustacea, Portunidae) off Martinique, French Lesser Antilles

First record of the invasive swimming crab Charybdis hellerii (A. Milne Edwards, 1867) (Crustacea, Portunidae) off Martinique, French Lesser Antilles

Variations in the diet and stable isotope ratios during the ovarian development of female yellowfin tuna (Thunnus albacares) in the Western Indian Ocean

The feeding strategy of female yellowfin tuna (Thunnus albacares) during their reproductive cycle was investigated using a combination of different trophic tracers, i.e., stomach contents and dual stable isotope analysis, along with an assessment of ovarian development based on a histological analysis. To complete these analyses, we collected 215 female yellowfin from the Western Indian Ocean in 2009 and 2010. From these fish, we noted the ovarian development and analyzed the contents of 166 non-empty stomachs and 104 liver and muscle tissue samples. Stomach content analysis identified a large variety of prey species (45 prey families), key groups including crustaceans dominated by the swimming crab Charybdis smithii and crustacean larvae; fish dominated by the cigarfish Cubiceps pauciradiatus; and cephalopods dominated by ommastrephids Sthenoteuthis oualaniensis and Ornithoteuthis volatilis. Individuals capable of spawning appeared to feed intensively, particularly on cigarfish, during the reproductive period. From the mean reconstituted weight values of the preys, our results indicated that this intensive feeding led to increased amounts of acquired energy. The results of the stable isotope analyses, carried out on the muscle and liver tissues, indicated a clear decrease in values from north to south. These analyses also showed that liver δ15N values in spawning females were significantly lower than those in immature and developing individuals. This latter observation highlights the differences in metabolic processes that occur between tissues during ovarian development and underlines the importance of the liver in energy acquisition and mobilization in female yellowfin tuna during reproduction.