scholarly journals Prey preferences, consumption rates and predation effects of Asian shore crabs (Hemigrapsus takanoi) in comparison to native shore crabs (Carcinus maenas) in northwestern Europe

2021 ◽  
Vol 51 (5) ◽  
Author(s):  
Annika Cornelius ◽  
Katerina Wagner ◽  
Christian Buschbaum
Keyword(s):  
Feeding Behavior ◽  
Wadden Sea ◽  
Feeding Habits ◽  
Carcinus Maenas ◽  
Shore Crab ◽  
Crab Species ◽  
Blue Mussels ◽  
Pacific Oysters ◽  
Shore Crabs ◽  
Consumption Rates

AbstractThe Asian brush-clawed shore crab Hemigrapsus takanoi was introduced to the northern Wadden Sea (southeastern North Sea) in 2009 and now represents one of the most abundant brachyuran crab species. Abundance studies revealed an increase of mean crab densities on mixed reefs of native blue mussels (Mytilus edulis) and Pacific oysters (Magallana gigas) from 18 individuals m−2 in 2011 to 216 individuals m−2 in 2020. Despite its current high densities only little is known about the feeding habits of H. takanoi, its effects on prey populations and on the associated community in the newly invaded habitat. We summarize results of individual field and laboratory experiments that were conducted to assess feeding habits and consumption effects caused by Asian brush-clawed shore crabs and, additionally, compare the feeding ecology of H. takanoi with the one of the native shore crab Carcinus maenas. Field experiments manipulating crab densities revealed that both crab species affected the recruitment success of blue mussels, Pacific oysters and Australian barnacles (Austrominius modestus) with highest number of recruits at crab exclusion. However, endobenthic polychaetes within the reefs were differently affected. Only the native C. maenas caused a significant reduction in polychaete densities, whereas the introduced H. takanoi had no effect. Additional comparative laboratory studies revealed that single C. maenas consume more juvenile blue mussels than Asian brush-clawed shore crabs of the same size class. When offering amphipods as a mobile prey species, we found the same pattern with higher consumption rates by C. maenas than by H. takanoi. For Asian but not for native shore crabs, we detected a sex-dependent feeding behavior with male H. takanoi preferring blue mussels, while females consumed more amphipods. Considering mean crab densities and feeding behavior, our results suggest that despite lower consumption rates of single crabs, Asian brush-clawed shore crabs can cause stronger impacts on prey organisms than the native C. maenas, because H. takanoi exceeds their densities manifold. A strong impact of the invader on prey populations is supported by low amphipod occurrence at sites where H. takanoi density is high in the study area. Thus, the introduced Asian brush-clawed shore crab is an additional consumer with significant effects on the associated community of mixed reefs of mussels and oysters in the Wadden Sea.

scholarly journals First record of the endoparasitic isopod Portunion maenadis (Giard, 1886) (Epicaridea: Entoniscidae) in shore crabs in the Wadden Sea and a review of its distribution in Europe

2019 ◽  
Vol 49 (6) ◽  
pp. 2931-2936
Author(s):  
Annika Cornelius ◽  
Andreas M. Waser ◽  
Christian Buschbaum ◽  
David W. Thieltges
Keyword(s):  
New Record ◽  
Wadden Sea ◽  
Morphological Changes ◽  
Carcinus Maenas ◽  
First Record ◽  
Shore Crab ◽  
Energy Budgets ◽  
Future Research ◽  
Shore Crabs ◽  
Distribution In Europe

AbstractThe knowledge on the distribution and abundance of marine parasites is still limited, even for those occurring on relatively well studied host species with high ecological importance. Here we report on the first record of the entoniscid Portunion maenadis (Giard, 1886) in European shore crabs (Carcinus maenas L., 1758) in the Wadden Sea and provide a quantitative review of the parasite’s distribution in Europe based on published literature and biodiversity database records. Our new record closes a distribution gap of P. maenadis between previous southern observations in Portugal and France and northern occurrences in Denmark and Sweden. The additional literature survey suggests that P. maenadis is not very common and only occurs at scattered localities with prevalence of infestations usually well below 10% in host crab populations. However, the 45% prevalence observed in our study in November 2018 in the southern Wadden Sea indicates that also higher prevalences can occur. As the adult parasites feed on their host’s hemolymph they are likely to have consequences for the host’s energy budgets. In addition, infestations lead to morphological changes in the form of feminisation of male crabs (i.e. broader pleon, slender claws, bulging carapace) which we observed in several individuals. With this new record and literature review, we hope to spark future research into the distribution of this intriguing parasite species as well as on the impacts of infestations on shore crab hosts.

scholarly journals Influence of temperature on intraspecific, unbalanced dyadic contests between crabs

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7845
Author(s):  
Allan T. Souza ◽  
Felipe O. Ribas ◽  
João F. Moura ◽  
Claudia Moreira ◽  
Joana Campos ◽  
...  
Keyword(s):  
Carapace Width ◽  
Carcinus Maenas ◽  
Individual Characteristics ◽  
The Body ◽  
Shore Crab ◽  
Temperature Conditions ◽  
Red Color ◽  
Shore Crabs ◽  
Influence Of Temperature On ◽  
Globally Distributed

Intraspecific agonistic interactions are widespread across the animal kingdom, with many individual morphological and physiological characteristics playing important roles in the fate of disputes. Additionally, changes to environmental conditions can influence the outcomes of animal contests. The shore crab (Carcinus maenas) is a globally distributed species, present in numerous coastal and estuarine temperate systems around the world. Although shore crabs are highly tolerant to changes in temperature, this parameter has important physiological effects on the species’ ecology, while its effects on behavior are not fully understood. Our study aims to investigate how different individual characteristics (such as sex, color morphotype, carapace and chela morphology) and temperature conditions affect the dyadic interactions between shore crabs when disputing food resources. In general, the differences in carapace width between opponents, their sexes, color morphotypes and the temperature conditions interacted and were important predictors of the contest fate. We found that the body size and color morphotype of C. maenas determined the fate of dyadic disputes. However, the higher temperatures disrupted the well-established dominance of the larger red color morphotype individuals. Overall, the agonistic contest results suggest higher plasticity than previously acknowledged.

scholarly journals Mycosis Is a Disease State Encountered Rarely in Shore Crabs, Carcinus maenas

Pathogens ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 462
Author(s):  
Charlotte E. Davies ◽  
Sophie H. Malkin ◽  
Jessica E. Thomas ◽  
Frederico M. Batista ◽  
Andrew F. Rowley ◽  
...  
Keyword(s):  
Immune Cell ◽  
Fungal Infections ◽  
Novel Species ◽  
Carcinus Maenas ◽  
Shore Crab ◽  
Marine Animals ◽  
Cell Reactivity ◽  
Shore Crabs ◽  
Swansea Bay ◽  
Disease Signatures

There is a paucity of knowledge regarding the diversity and impact(s) of disease-causing fungi in marine animals, especially shellfish. In efforts to address this knowledge gap for the shore crab Carcinus maenas, a year-long disease screen was carried out across two sites in Swansea Bay (Wales, UK) with a view to characterising putative fungal infections. Crabs were sampled between November 2017 and October 2018, and screened systematically for disease signatures using haemolymph (blood) preparations, targeted PCR and tissue histopathology. Strikingly, mycosis was confirmed in ~0.4% of total crabs tested (n = 1191) and restricted to one location only (Mumbles Pier). Clinical infections were observed in four out of four infected crabs. In these animals, the gills and hepatopancreas were congested with fungal morphotypes. In addition, some evidence indicates haemocyte (immune cell) reactivity toward the fungi. Phylogenetic placement of the partial internal transcribed spacer (ITS1) gene regions amplified from three mycotic crabs revealed the causative agent to be related to hypocrealean fungi, thereby representing a novel species.

Fecampia erythrocephala rediscovered: prevalence and distribution of a parasitoid of the European shore crab, Carcinus maenas

2002 ◽  
Vol 82 (6) ◽  
pp. 955-960 ◽  
Author(s):  
Armand M. Kuris ◽  
Mark E. Torchin ◽  
Kevin D. Lafferty
Keyword(s):  
Carapace Width ◽  
Carcinus Maenas ◽  
Ecological Assessment ◽  
Shore Crab ◽  
Site Specificity ◽  
Habitat Distribution ◽  
Large Size ◽  
Cancer Pagurus ◽  
Host Growth ◽  
Shore Crabs

An ecological assessment of Fecampia erythrocephala, reporting its habitat distribution, abundance, host specificity, size-specific prevalence, frequency distribution among hosts, effect on host growth, and its site specificity within these hosts is presented. At the Isle of Man and near Plymouth, Fecampia erythrocephala cocoons were generally abundant on the undersides of rocks in the Ascophyllum and Fucus serratus zones. Infected crabs were also most common in these habitats. Both Carcinus maenas and Cancer pagurus were parasitized at similar prevalences, although the former species was relatively much more common in the habitats where the worm cocoons were abundant. Fecampia erythrocephala did not infect crabs larger than 11 mm carapace width, and prevalence decreased significantly with crab size. Prevalences reached 11% in areas where cocoons were abundant. Together with the large size of these worms relative to the size of the host crabs and the observations on worm emergence, these life history features indicate that F. erythrocephala is a parasitoid of young shore crabs. Fecampia erythrocephala cocoon abundance is often high in localized areas and size-prevalence information suggests that worms mature rapidly in these crabs. This suggests that F. erythrocephala is an important contributor to crab mortality and to the ecology of shore crabs at these sites.

scholarly journals Diagnosis and prevalence of two new species of haplosporidians infecting shore crabs Carcinus maenas: Haplosporidium carcini n. sp., and H. cranc n. sp.

Parasitology ◽  
2020 ◽  
Vol 147 (11) ◽  
pp. 1229-1237 ◽  
Author(s):  
Charlotte E. Davies ◽  
David Bass ◽  
Georgia M. Ward ◽  
Frederico M. Batista ◽  
Sophie H. Malkin ◽  
...  
Keyword(s):  
New Species ◽  
Phylogenetic Analyses ◽  
Carcinus Maenas ◽  
Small Subunit ◽  
Shore Crab ◽  
Phylogenetic Characterization ◽  
South Wales ◽  
Two New Species ◽  
Shore Crabs ◽  
Swansea Bay

AbstractThis study provides a morphological and phylogenetic characterization of two novel species of the order Haplosporida (Haplosporidium carcini n. sp., and H. cranc n. sp.) infecting the common shore crab Carcinus maenas collected at one location in Swansea Bay, South Wales, UK. Both parasites were observed in the haemolymph, gills and hepatopancreas. The prevalence of clinical infections (i.e. parasites seen directly in fresh haemolymph preparations) was low, at ~1%, whereas subclinical levels, detected by polymerase chain reaction, were slightly higher at ~2%. Although no spores were found in any of the infected crabs examined histologically (n = 334), the morphology of monokaryotic and dikaryotic unicellular stages of the parasites enabled differentiation between the two new species. Phylogenetic analyses of the new species based on the small subunit (SSU) rDNA gene placed H. cranc in a clade of otherwise uncharacterized environmental sequences from marine samples, and H. carcini in a clade with other crustacean-associated lineages.

Waterborne copper causes gill damage and hemolymph hypoxia in the shore crab Carcinus maenas

1993 ◽  
Vol 71 (8) ◽  
pp. 1569-1576 ◽  
Author(s):  
L. Nonnotte ◽  
F. Boitel ◽  
J. P. Truchot
Keyword(s):  
Carcinus Maenas ◽  
Lactate Concentration ◽  
Gill Tissue ◽  
Major Effect ◽  
Blood Oxygenation ◽  
Shore Crab ◽  
Structural Alterations ◽  
Arterial Blood ◽  
Shore Crabs ◽  
Gill Lamellae

The ultrastructure of gill lamellae was studied in shore crabs, Carcinus maenas, exposed to sublethal (0.5 mg∙L−1) and lethal (2 mg∙L−1) concentrations of waterborne copper for various durations. Oxygen tension, pH, and lactate concentration in arterial blood were determined in parallel studies. Extensive structural alterations involving cellular hyperplasia, vacuolization, and necrosis were found after 5–6 days of exposure to both sublethal and lethal copper levels. This led to considerable thickening of the gill epithelium and reduction of haemolymph spaces, resulting in restriction of respiratory gas exchange as shown by a marked hypoxemia. Ensuing lactacidemia suggests that tissue hypoxia was probably the major effect of the toxicant at lethal levels. In sublethal conditions, partial repair of gill tissue and recovery of normal blood oxygenation and pH were observed after 18 days of exposure.

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