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The crustacean molting cycle is triggered by the elevation of ecdysteroid levels in the hemolymph during late pre‐molt. It is known that these animals absorb water through the intestine and gills to promote bodily swelling and rupture of the old exoskeleton. The participation of two membrane proteins responsible for the most uptake of water during the late pre‐molt has been shown in the gill and gut cells of the freshwater shrimp Palaemon argentinus: Na+/K+‐ATPase (NKA), which generates an osmoionic gradient, and Aquaporins (AQPs), water channels, which provide higher water permeability. Studies investigating the action of ecdysteroids on these proteins are scarce. Therefore, we investigated 20‐hydroxyecdisone (20E) in relation to the regulation of NKA and AQPs in the gill and gut cells of P. argentinus. We exposed primary cultures of both gut and gill cells to 20E. Gill cells treated with hormone in the presence of NKA‐blockers, exhibited a reduction in volume, and cells treated with 20E showed a greater expression of NKA than untreated cells. Additionally, gills cells treated with 20E showed an increase in volume (∼60%), which the aquaporin inhibitor (HgCl2) prevented. The participation of AQPs in the influx of water was corroborated by a greater expression of AQP in cells treated with 20E compared to untreated cells. Gut cells of animals in intermolt exposed to hormone (20E) maintained their initial cell volume. With the addition of HgCl2, these cells showed a reduction in volume similar to cells of animals in pre‐molt. Immunocytochemistry showed a high expression of AQP in gut cells treated with 20E. These findings suggest that 20E regulates the expression of AQP and NKA in the late pre‐molt, to provide water uptake for molting. This work offers new perspectives concerning the molting hormone, placing it as a crucial part of water uptake for ecdysis. [ABSTRACT FROM AUTHOR]

This study examined the levels of 210Po and the annual effective dose in edible crustaceans from the Santa Barbara River, Nembe. The crustaceans analyzed included Crab (Cardisoma crassum), Prawn (Macrobrachium rosenbergii), Shrimp (Penaeus notalis), and Crayfish (Decapoda reptania). The concentration of 210Po in the crustaceans was measured using an alpha spectrometric procedure, with 209Po tracer used as a yield monitor after acidified HNO3 digestion. The results indicated trace amounts of 210Po in the different crustaceans, with a concentration of 24.17 Bq kg−1 fresh weight in Crab, 0.01 Bq kg−1 fresh weight in Prawn, 50.89 Bq kg−1 fresh weight in Shrimp, and 40.71 Bq kg−1 fresh weight in Crayfish. The doses of 210Po concentration from the crustaceans were calculated using ingestion dose coefficients of 1.2 μSv Bq−1 for adults, as provided by the regulatory framework that protects humans from exposure to ionizing radiation. The calculated annual effective doses suggested low levels of exposure to crustacean consumers, with values below the recommended limit of 1000 μSv y−1 set by the ICRP for effective dose. The crustaceans with the highest annual committed effective doses of 210Po were Penaeus notalis and Decapoda reptania. However, even small amounts of 210Po in crustaceans can lead to contamination that may be harmful to human health. [ABSTRACT FROM AUTHOR]

In this work, we cloned and functionally expressed two novel GABAA receptor subunits from Procambarus clarkii crayfish. These two new subunits, PcGABAA‐α and PcGABAA‐β2, revealed significant sequence homology with the PcGABAA‐β subunit, previously identified in our laboratory. In addition, PcGABAA‐α subunit also shared a significant degree of identity with the Drosophila melanogaster genes DmGRD (GABA and glycine‐like receptor subunits of Drosophila) as well as PcGABAA‐β2 subunit with DmLCCH3 (ligand‐gated chloride channel homolog 3). Electrophysiological recordings showed that the expression in HEK cells of the novel subunits, either alone or in combination, failed to form functional homo‐ or heteromeric receptors. However, the co‐expression of PcGABAA‐α with PcGABAA‐β evoked sodium‐ or chloride‐dependent currents that accurately reproduced the time course of the GABA‐evoked currents in the X‐organ neurons from crayfish, suggesting that these GABA subunits combine to form two types of GABA receptors, one with cationic selectivity filter and the other preferentially permeates anions. On the other hand, PcGABAA‐β2 and PcGABAA‐β co‐expression generated a chloride current that does not show desensitization. Muscimol reproduced the time course of GABA‐evoked currents in all functional receptors, and picrotoxin blocked these currents; bicuculline did not block any of the recorded currents. Reverse transcription polymerae chain reaction (RT‐PCR) amplifications and FISH revealed that PcGABAA‐α and PcGABAA‐β2 are predominantly expressed in the crayfish nervous system. Altogether, these findings provide the first evidence of a neural GABA‐gated cationic channel in the crayfish, increasing our understanding of the role of these new GABAA receptor subunits in native heteromeric receptors. [ABSTRACT FROM AUTHOR]

Composition, size distribution, structure, and function of deep‐sea marine communities must be understood before they are impacted by anthropogenic effects. The deep‐sea ecosystem of the Colombian Caribbean Sea is unexploited with no fishing activity ever registered. We quantified the current state of the marine community using body size distribution (size‐spectra), size‐based indicators, minimum length (LMIN), maximum length (LMAX), average length (Lmean), standard deviation of length (LSD), 10th and 90th percentiles of the length distribution, Shannon–Wiener diversity (H′), and Pielou's evenness (J′) to generate a baseline of potential ecological indicators that contribute to management and conservation of the Colombian bento‐demersal community of deep‐sea marine ecosystem. Sampling was in the Colombian Caribbean Sea at 58 stations during four samplings in August and December 2009, 21 stations in March and May 2010, and 45 stations from August to December 2020, using the swept area method, at depths of 200–550 m. Catches included >50% families and species of fish, followed by 27 families (30%) and 33 and species (37%) of crustaceans. Chondrichthyes included 14% families and 9–11% species. Cephalopods included 2–3% families and 1–4% species. Size‐spectra analysis confirmed expected values for unexploited communities in three sampling years for teleostei, crustacea, and whole community. [ABSTRACT FROM AUTHOR]

In the dark, expansive habitat of the deep sea, the production of light through bioluminescence is commonly used among a wide range of taxa. In decapod crustaceans, bioluminescence is only known in shrimps (Dendrobranchiata and Caridea) and may occur in different modes, including luminous secretions that are used to deter predators and/or from specialised light organs called photophores that function by providing camouflage against downwelling light. Photophores exhibit an extensive amount of morphological variation across decapod families: they may be internal (of hepatic origin) or embedded in surface tissues (dermal), and may possess an external lens, suggesting independent origins and multiple functions. Within Dendrobranchiata, we report bioluminescence in Sergestidae, Aristeidae, and Solenoceridae, and speculate that it may also be found in Acetidae, Luciferidae, Sicyonellidae, Benthesicymidae, and Penaeidae. Within Caridea, we report bioluminescence in Acanthephyridae, Oplophoridae, Pandalidae, and new observations for Pasiphaeidae. This comprehensive review includes historic taxonomic literature and recent studies investigating bioluminescence in all midwater and deep benthic shrimp families. Overall, we report known or suspected bioluminescence in 157 species across 12 families of decapod shrimps, increasing previous records of bioluminescent species by 65%. Mounting evidence from personal observations and the literature allow us to speculate the presence of light organs in several families thought to lack bioluminescence, making this phenomenon much more common than previously reported. We provide a detailed discussion of light organ morphology and function within each group and indicate future directions that will contribute to a better understanding of how deep‐sea decapods use the language of light. [ABSTRACT FROM AUTHOR]

Background: Anxiety refers to the pathological persistence and intensification of emotional responses to danger, affecting health from psychological and physical aspects. Serotonin is an important neurotransmitter involved in the onset of anxiety. Methods and Results: To explore the biological changes in the formation of anxiety in crustaceans under the regulation of serotonin, we applied the open field-like test method for assessing anxiety states of larval Portunus trituberculatus, a highly aggressive crustacean species with a more simple neural structure compared with rodents and mammals. Compared with the control group, serotonin treatment resulted in a significant decrease in the time spent by the larvae in the central zone, suggesting anxiety-like behavior. Clonazepam treatment reversed this result and provided further evidence that the behavior of larval P. trituberculatus displayed anxiety. Moreover, a non-targeted metabolomic analysis found a significant alteration in the metabolites involved in tryptophan metabolism pathways associated with anxiety, including L-kynurenine, N-acetyl serotonin, and serotonin. These metabolites are involved in the serotonin pathway, the kynurenine pathway, and other pathways that affect anxiety through tryptophan metabolism. There were no significant differences in tryptophan metabolism levels between the control and clonazepam treatment groups. Conclusions: Our results demonstrate the possible existence of anxiety-like behavior in the larvae of P. trituberculatus from two perspectives. Being a species with a simpler neural structure than that of mammals, the larvae of P. trituberculatus offer a convenient model for studying the mechanisms of anxiety in crustaceans. [ABSTRACT FROM AUTHOR]

Abstract This study examined the levels of 210Po and the annual effective dose in edible crustaceans from the Santa Barbara River, Nembe. The crustaceans analyzed included Crab (Cardisoma crassum), Prawn (Macrobrachium rosenbergii), Shrimp (Penaeus notalis), and Crayfish (Decapoda reptania). The concentration of 210Po in the crustaceans was measured using an alpha spectrometric procedure, with 209Po tracer used as a yield monitor after acidified HNO3 digestion. The results indicated trace amounts of 210Po in the different crustaceans, with a concentration of 24.17 Bq kg−1 fresh weight in Crab, 0.01 Bq kg−1 fresh weight in Prawn, 50.89 Bq kg−1 fresh weight in Shrimp, and 40.71 Bq kg−1 fresh weight in Crayfish. The doses of 210Po concentration from the crustaceans were calculated using ingestion dose coefficients of 1.2 μSv Bq−1 for adults, as provided by the regulatory framework that protects humans from exposure to ionizing radiation. The calculated annual effective doses suggested low levels of exposure to crustacean consumers, with values below the recommended limit of 1000 μSv y−1 set by the ICRP for effective dose. The crustaceans with the highest annual committed effective doses of 210Po were Penaeus notalis and Decapoda reptania. However, even small amounts of 210Po in crustaceans can lead to contamination that may be harmful to human health.

The Australian Museum has a large palaeontological collection of Triassic specimens from the Sydney Basin, including many type specimens. This study reviewed every presently described Sydney Basin Hawkesbury Sandstone plant and animal taxon that has representative specimens held in the Australian Museum. Fifty-two taxa are included from numerous sites. These include three amphibians, twenty-eight fishes, eleven insects, one horseshoe “crab”, one scorpion, three crustaceans, two molluscs and three plants. Basic taxonomic history is noted, together with specimen registration numbers and their position in the collection. Also included are references to relevant specimens held in the Geological Survey of New South Wales and the Natural History Museum, London collections. Images of every taxon are included. To place the collection in context, particularly for educators working with students, brief descriptions of the geology that forms the Hawkesbury Sandstone, and the inferred ecosystems that existed during the Middle Triassic, are included. The results of this study will help to facilitate further researchers by providing important details of the fossil collections held at the Australian Museum.

Abstract Background China is the hotspot of global freshwater crab diversity, but their wild populations are facing severe pressures associated with anthropogenic factors, necessitating the need to map their taxonomic and genetic diversity and design conservation policies. Results Herein, we sequenced the mitochondrial genome of a Chinese freshwater crab species Bottapotamon fukienense, and found that it is fragmented into two chromosomes. We confirmed that fragmentation was not limited to a single specimen or population. Chromosome 1 comprised 15,111 base pairs (bp) and there were 26 genes and one pseudogene (pseudo-nad1) encoded on it. Chromosome 2 comprised 8,173 bp and there were 12 genes and two pseudogenes (pseudo-trnL2 and pseudo-rrnL) encoded on it. Combined, they comprise the largest mitogenome (23,284 bp) among the Potamidae. Bottapotamon was the only genus in the Potamidae dataset exhibiting rearrangements of protein-coding genes. Bottapotamon fukienense exhibited average rates of sequence evolution in the dataset and did not differ in selection pressures from the remaining Potamidae. Conclusions This is the first experimentally confirmed fragmentation of a mitogenome in crustaceans. While the mitogenome of B. fukienense exhibited multiple signs of elevated mitogenomic architecture evolution rates, including the exceptionally large size, duplicated genes, pseudogenisation, rearrangements of protein-coding genes, and fragmentation, there is no evidence that this is matched by elevated sequence evolutionary rates or changes in selection pressures.

Some hosts harbor more parasites than others. Overdispersion of parasitism suggests that coevolution with parasites may be more important to the biology and ecology of certain species. We examined patterns of parasitism and host traits in fished decapod crustaceans, which are economically and ecologically important worldwide. Using a synthesis approach, we determine that host life history, including habitat, longevity, sociality, invasion history, and fisheries involvement, correlate with the number and type of parasite species harbored. Indicator species analysis revealed close relationships between decapods and certain parasite groups, including crabs with rhizocephalans and dinoflagellates; crayfish with mesomycetozoans, oomycetes, branchiobdellids, and fungi; lobsters with copepods and amoebae; and shrimp with viruses. In contrast, Nematomorpha and Nemertea appear to be under-represented and under-studied as parasite groups in decapods. Decapods that are commercially fished, aquacultured, introduced outside their native range, and/or exhibit parental care tend to have higher parasite species richness (PSR). Parasite richness also increases with how well-studied a host group is, which we addressed with a machine learning algorithm that predicts false negative associations. Geographic range is commonly positively correlated with parasite richness, however reliable ranges are not available for most decapod species, highlighting a significant future research need. Identifying patterns such as these increases our broad understanding of decapod disease ecology but also enabled us to develop a series of recommendations on how to focus future research, management, and aquaculture development efforts. [ABSTRACT FROM AUTHOR]

In marine ecosystems, organisms often form enduring associations with other species, creating rich symbiotic communities within benthic hosts. Among these associations, mimetic pigmentation—where symbionts adopt colors resembling their hosts—plays a key role in predator avoidance strategies. Despite its prevalence, this phenomenon remains poorly understood. This research aims to explore pigmentation dynamics in four symbiotic pairs: (i) Zenopontonia soror with Culcita novaeguineae, (ii) Synalpheus stimpsonii with Phanogenia distincta, and (iii) Tuleariocaris holthuisi, and (iv) Arete indicus with Echinometra mathaei. The study involves monitoring symbiont survivability, standardized photography to measure color variation, histological analysis to locate pigment-associated cells, and HPLC (High Performance Liquid Chromatography) to characterize pigment chemical composition. Results indicate a strong host dependency for all symbionts, with three species showing reliance on host metabolites. Host-symbiont separation affects symbiont pigmentation, leading to dynamic color changes. Histological analysis reveals chromatophores in all species, with A. indicus exhibiting two distinct layers of chromatophores containing different pigments. Chemical analysis shows differences in pigments between partners, with carotenoids detected in both Z. soror and C. novaeguineae, while S. stimpsonii and P. distincta show carotenoids predominantly in the symbiont. These findings enhance our understanding of mimetic coloration mechanisms in symbiotic shrimps, advancing knowledge of symbiont ecology and host interactions. [ABSTRACT FROM AUTHOR]

Crab fisheries play a crucial role in global fishery economics, but they heavily rely on wild catches. With the decline and exploratory limits of wild populations, expanding the scale and production of aquaculture becomes vital for the sustainability of crab fisheries. The development of crab aquaculture encounters significant dietary challenges, stemming from suboptimal formulated feeds and inefficient feeding management. Leveraging insights from crab foraging behaviours offers a promising solution to these issues; however, progress is hindered by a lack of comprehensive behavioural data and the underappreciation of these insights in aquaculture. To bridge this gap, we systematically examine the progress in studies of crab foraging behaviour, analysing the influences of predators, prey, and environmental characteristics, and discuss possibilities for future research and development in the field by combining these findings with the demands of aquaculture. This review identifies a discrepancy in research focus, with inadequate emphasis on the major cultured species and their behavioural responses to factors limiting aquaculture productivity, aiming to enhance our comprehension of crab foraging behaviour and facilitate growth in the crab industry. [ABSTRACT FROM AUTHOR]

This study reports the presence of Percnon gibbesi in the North Adriatic Sea, specifically at Cape Kamenjak, Croatia. The species was first observed in the Mediterranean in 1999, and has rapidly proliferated across the region, with Cape Kamenjak now representing its northernmost finding. Seven individuals were identified during free-diving activities in Pinižule Bay in December 2023. Follow-up surveys in January 2024 revealed their presence approximately 15 meters from the shore, under large boulders, at depths ranging from 2.6 to 3.6 meters, with water temperatures ranging from 13 to 15 °C. Morphological examinations confirmed the specimen as male P. gibbesi, with a carapace length of 15 mm, carapace width of 14.3 mm, and a weight of 1.87 g. Shipping was identified as a primary vector of introduction due to the proximity of Cape Kamenjak to major Mediterranean ports. This research provides insights into the invasion dynamics of P. gibbesi in the northern Adriatic, urging proactive management strategies and collaborative efforts in monitoring programs. [ABSTRACT FROM AUTHOR]

Context: Climate change reportedly affects global fisheries, including the highly valuable swimming crabs, an important benthic species in Asian waters. Aims: The aim of this study was to determine the effects of El Niño–Southern Oscillation (ENSO) events on catch rates and habitat suitability of Portunus pelagicus , Portunus sanguinolentus and Charybdis feriatus in the Taiwan Strait. Methods: We combined marine remote sensing data with Taiwanese trap vessel data to develop a weighted habitat suitability index modelling and analyse the recruitment dynamics of swimming crabs in different ENSO events. Key results: Our results suggest that Increasing salinity (>33.5 PSU) and sea temperature (>18.6°C) during La Niña events had a positive effect on stock recruitment and habitat suitability index of P. pelagicus and C. feriatus. By contrast, P. sanguinolentus were not affected by ENSO events. The low catch rates for P. sanguinolentus in normal years and for C. feriatus and P. pelagicus in normal and El Niño years were highly consistent with the significant shrinkage of the habitat suitability index. Conclusions: Monitoring climate change and environmental factors is essential for understanding their effects on marine ecosystems. Implications: This research can help implement sustainable crab fisheries. Climate change affects marine environments, disrupting fisheries and ecosystems. Marine crustaceans, like swimming crabs in the Taiwan Strait, respond by altering catchability and habitat suitability. El Niño events significantly affect their fishing grounds, whereas water exchange and wind changes influence temperature, salinity and water mass structure. During La Niña years, positive ocean temperature and salinity anomalies may further affect the optimal habitats and catchability of swimming crabs. [ABSTRACT FROM AUTHOR]

Subterranean and surface habitats are in stark contrast in several environmental factors. Therefore, adaptation to the subterranean environment typically impedes the (re)colonisation of surface habitats. The genus Niphargus includes amphipod crustaceans that primarily occupy subterranean habitats. All its species show typical adaptations to the subterranean environment. However, some Niphargus species occur in surface‐subterranean ecotones. To understand whether (i) habitat‐based phenotypic divergence is present between the cave and the ecotone species and (ii) similar phenotypes emerge independently in each ecotone, we studied morphological divergence between four cave and four ecotone Niphargus species based on 13 functional morphological traits. To account for different selection acting on the sexes, we included both males (N = 244) and females (N = 222). Nine out of 13 traits showed habitat‐divergence. Traits related to feeding and crawling were shorter, while traits related to oxygenation were larger in ecotone species. Eleven out of 13 traits were sexually dimorphic. Traits related to oxygenation and crawling were larger in females, while the trait related to swimming was larger in males. We found that the extent of sexual dimorphism differs between the habitats in eight traits related to sensing, feeding, oxygenation and crawling. Additionally, we found that in certain traits related to sensing and oxygenation, habitat‐related differences are only present in one sex, but not the other. We conclude that the detected differences between the cave and the ecotone species indicate divergent evolution, where similarities among the different species within habitat type indicate convergent evolution. The high degree of sexual dimorphism paired with differences in sexual dimorphism between the habitats in certain traits suggest that sexual and fecundity selections have comparable effects to environmental selection. Thus, studies of habitat‐dependent adaptations investigating one sex only, or not considering sexual dimorphism, can lead to erroneous conclusions. [ABSTRACT FROM AUTHOR]

In this study, the complex organization of the AnG in the giant freshwater prawn Macrobrachium rosenbergii was revealed using various techniques, including conventional histology, histochemistry, scanning electron microscopy, and X-ray tomography. The results showed the diversity of cells in the AnG and the detailed organization of the labyrinth's tubule into four radiated areas from the central to peripheral zones. The study also demonstrated the expression of some vertebrate kidney-associated homolog genes, aquaporin (AQP), solute carrier family 22 (SLC-22), nephrin, and uromodulin, in the AnG by qPCR. The result of in situ hybridization further showed the localization of SLC-22 and AQP transcript in the bladder and labyrinth's epithelium, specifically in regions 2, 3, and 4. Additionally, the study revealed neuropeptide expressions in the AnG by qPCR and in situ hybridization, i.e., crustacean hyperglycemic hormone (CHH) and molt inhibiting hormone (MIH), implying that the AnG may have a role in hormone production. Moreover, male and female prawns exhibited different levels of AQP, SLC-22, nephrin, and CHH expressions during the premolt and intermolt stages, suggesting a crucial role relevant to the molting stages. In conclusion, this study clarified the complex structure of the AnG in M. rosenbergii and demonstrated for the first time the expression of vertebrate kidney-associated genes and the possible endocrine role of the AnG. Further investigation is needed to clarify the role of these genes, particularly during ecdysis. The implications of these findings could significantly advance our understanding of the AnG in decapod crustaceans. [ABSTRACT FROM AUTHOR]

Species with widespread distributions play a crucial role in our understanding of climate change impacts on population structure. In marine species, population structure is often governed by both high connectivity potential and selection across strong environmental gradients. Despite the complexity of factors influencing marine populations, studying species with broad distribution can provide valuable insights into the relative importance of these factors and the consequences of climate‐induced alterations across environmental gradients. We used the northern shrimp Pandalus borealis and its wide latitudinal distribution to identify current drivers of population structure and predict the species' vulnerability to climate change. A total of 1514 individuals sampled across 24° latitude were genotyped at high geographic (54 stations) and genetic (14,331 SNPs) resolutions to assess genetic variation and environmental correlations. Four populations were identified in addition to finer substructure associated with local adaptation. Geographic patterns of neutral population structure reflected predominant oceanographic currents, while a significant proportion of the genetic variation was associated with gradients in salinity and temperature. Adaptive landscapes generated using climate projections suggest a larger genomic offset in the southern extent of the P. borealis range, where shrimp had the largest adaptive standing genetic variation. Our genomic results combined with recent observations point to further deterioration in southern regions and an impending vulnerable status in the regions at higher latitudes for P. borealis. They also provide rare insights into the drivers of population structure and climatic vulnerability of a widespread meroplanktonic species, which is crucial to understanding future challenges associated with invertebrates essential to ecosystem functioning. [ABSTRACT FROM AUTHOR]

Background: China is the hotspot of global freshwater crab diversity, but their wild populations are facing severe pressures associated with anthropogenic factors, necessitating the need to map their taxonomic and genetic diversity and design conservation policies. Results: Herein, we sequenced the mitochondrial genome of a Chinese freshwater crab species Bottapotamon fukienense, and found that it is fragmented into two chromosomes. We confirmed that fragmentation was not limited to a single specimen or population. Chromosome 1 comprised 15,111 base pairs (bp) and there were 26 genes and one pseudogene (pseudo-nad1) encoded on it. Chromosome 2 comprised 8,173 bp and there were 12 genes and two pseudogenes (pseudo-trnL2 and pseudo-rrnL) encoded on it. Combined, they comprise the largest mitogenome (23,284 bp) among the Potamidae. Bottapotamon was the only genus in the Potamidae dataset exhibiting rearrangements of protein-coding genes. Bottapotamon fukienense exhibited average rates of sequence evolution in the dataset and did not differ in selection pressures from the remaining Potamidae. Conclusions: This is the first experimentally confirmed fragmentation of a mitogenome in crustaceans. While the mitogenome of B. fukienense exhibited multiple signs of elevated mitogenomic architecture evolution rates, including the exceptionally large size, duplicated genes, pseudogenisation, rearrangements of protein-coding genes, and fragmentation, there is no evidence that this is matched by elevated sequence evolutionary rates or changes in selection pressures. [ABSTRACT FROM AUTHOR]

Balanomorph (acorn) barnacles are found throughout the world's coastal oceans, and their success is dependent on a hard, mineralized, outer shell. Although macro-scale morphology of barnacle shells has been studied extensively, relatively little is known about shell properties at the micron-scale and if such properties vary among species. We assessed shell structure, mechanics, and composition in seven species of balanomorph barnacles from five genera. Three species, Amphibalanus amphitrite, Amphibalanus improvisus, and Austrominius modestus, were laboratory-reared, enabling direct comparison of shell properties of barnacles grown under the same conditions for the same duration. Four other species, Semibalanus balanoides, Amphibalanus eburneus, Chthamalus stellatus, and Tetraclita rubescens, were field-collected. At the macro- and meso-scales, shell properties varied markedly among species, with differences in the number of shell plates, the presence of canals within the plates, mineralization of the base, and shell plate thickness. At the micron-scale, however, structure was remarkably similar among species. Plates of all species were constructed of irregular micron-scale crystallites, with a broad range of crystallite dimensions observed within the same shell. Similarly, micromechanical properties did not vary among species, regardless of testing orientation. Calcium carbonate was identified as calcite in all species assessed with no other mineral phases present, and calcium content did not vary among species. Hence, despite variation in the overall macro- and meso-scale morphology of barnacles, all appear to be built using the same, evolutionarily conserved, mineralization pathway. [ABSTRACT FROM AUTHOR]

The goal of this study was to evaluate the trace element pollution in amarine ranching area in China based on molecular responses (expression of metallothionein and antioxidant enzyme genes), and biochemical biomarkers (metallothionein content, antioxidant enzyme activities, and malonaldehyde level) in four indicator species. We collected samples of two fish (Lateolabrax maculatus and Sebastes schlegelii), one crustacean (Charybdis japonica), andonegastropod(Rapana venosa) fromthewestern Furong Island marine ranching area and from an adjacent area in March 2022 and measuredthe traceelementcontent in these indicator species aswell as intheseawater andsediment.Wefoundthat thebioaccumulationcharacteristicsof traceelementsand the response patterns of biomarkers were species specific. Moreover, not every biomarker was significantly correlated with environmental trace element content.We then established two biomarker combinations indicative of trace element pollution in seawaterandsediment, respectively, basedonthe correlationbetweenbiomarkers and trace element contents. The selected biomarkers were integrated using integrated biomarker response version 2 (IBRv2). IBRv2 values in the studied marine ranching area were lower than those in the adjacent area. Additionally, these values were consistent with thebioaccumulation of traceelementsintheindicator species, theintegrated trace element pollution index for seawater, and the potential risk index for sediment. These results show that this multi-biomarker and multi-species IBRv2 approach provided a comprehensive diagnosis of trace element pollution in the marine ranching area. Therefore, its application may be beneficial for marine environmental monitoring and management in view of the ecotoxicological impact of pollutants on organisms. [ABSTRACT FROM AUTHOR]

Chitosan (CS), a biopolymer, holds significant potential in bone regeneration due to its biocompatibility and biodegradability attributes. While crustacean-derived CS is conventionally used in research, there is growing interest in fungal-derived CS for its equally potent properties in bone regenerative applications. Here, we investigated the physicochemical and biological characteristics of fungal (MDC) and crustacean (ADC)-derived CS scaffolds embedded with different concentrations of tricalcium phosphate minerals (TCP), i.e., 0(wt)%: ADC/MDC-1, 10(wt)%: ADC/MDC-2, 20(wt)%: ADC/MDC-3 and 30(wt)%: ADC/MDC-4. ADC-1 and MDC-1 lyophilised scaffolds lacking TCP minerals presented the highest zeta potentials of 47.3 ± 1.2 mV and 55.1 ± 1.6 mV, respectively. Scanning electron microscopy revealed prominent distinctions whereby MDC scaffolds exhibited striation-like structural microarchitecture in contrast to the porous morphology exhibited by ADC scaffold types. With regard to the 4-week scaffold mass reductions, MDC-1, MDC-2, MDC-3, and MDC-4 indicated declines of 55.98 ± 4.2%, 40.16 ± 3.6%, 27.05 ± 4.7%, and 19.16 ± 5.3%, respectively. Conversely, ADC-1, ADC-2, ADC-3, and ADC-4 presented mass reductions of 35.78 ± 5.1%, 25.19 ± 4.2%, 20.23 ± 6.3%, and 13.68 ± 5.4%, respectively. The biological performance of the scaffolds was assessed through in vitro bone marrow mesenchymal stromal cell (BMMSCs) attachment via indirect and direct cytotoxicity studies, where all scaffold types presented no cytotoxic behaviours. MDC scaffolds indicated results comparable to ADC, where both CS types exhibited similar physiochemical properties. Our data suggest that MDC scaffolds could be a potent alternative to ADC-derived scaffolds for bone regeneration applications, particularly for 10(wt)% TCP concentrations. [ABSTRACT FROM AUTHOR]

The study investigated heavy metal residues and bacterial pathogens in blue crab (Callinectes amnicola), crayfish (Nematopaelemon hastatus), giant tiger prawn (Penaeus monodon), and Indian prawn (Fenneropenaeus indicus) from crude oil impacted Niger Delta waters. Standard methods of analysis were applied in all determinations. Results indicate that chromium, lead, and mercury were within regulatory acceptable levels. Total viable count (TVC) was below threshold, while Vibrio cholerae, Vibrio parahaemolyticus, and Salmonella typhimurium were isolated from all crustacean species. The distribution pattern of pathogens showed blue crab accumulated the highest population of pathogens. Consumption of crustaceans from the location exemplifies conflict of nutrient benefits and risks. [ABSTRACT FROM AUTHOR]

Ostracods have frequently been reported as part of the active faunas in the wet phase of rice fields, but knowledge on the dormant ostracods during the dry period of the rice cycle has been limited, hindering a comprehensive understanding of their adaptation to the rice field environment. In this study, we record 11 dormant ostracod species by incubating soil samples from six desiccated rice fields in Yunnan Province of southwestern China. The dormant ostracod community was dominated by species of the family Cyprididae, accompanied by members of Candonidae, Ilyocyprididae, and Notodromadidae. Our data provide unequivocal evidence for the presence of dormant ostracods from all the four families of the superfamily Cypridoidea in desiccated rice fields, verifying that these ostracods adapt to the rice fields by desiccation-resistant stage. Considering the usually shallow penetration depth of ostracods, the frequent discoveries of dormant ostracods in 2‒4 cm depth in the soil profile were probably the result of ploughing. Despite overlap in species composition, the dormant ostracod community differs from the active community sampled at the same sites more than four years ago. This suggests temporal changes of faunal composition, although the ecological memory of the dormant community containing multiple generations and the different seasonal windows represented by the two types of communities should also be considered. The emergence of adults within the first two weeks of the incubation experiment suggests the presence of dormant instars in the soil rather than resting eggs alone. [ABSTRACT FROM AUTHOR]

In caridean shrimps, sexual systems vary from gonochorism to various forms of hermaphroditism. The shrimp Salmoneus carvachoi has been reported to exhibit both male (appendix masculina) and female (brooding embryos) anatomical characteristics simultaneously. Our aim was to examine the sexual system of S. carvachoi and to test the hypothesis of protandric simultaneous hermaphroditism (PSH) in this species. We analysed internal and external features using microscopy and histology techniques. Our analyses support the hypothesis of PSH in S. carvachoi and enabled the identification of male-phase and hermaphroditic individuals. All individuals exhibit a well-developed appendix masculina on the endopods of the second pleopods; however, small male-phase individuals possess only male gonopores, whereas larger hermaphroditic individuals possess both female and male gonopores. Hermaphrodites exhibit both male and female germinative cells in various stages of development, as well as an androgenic gland. Our study describes a novel sexual system for alpheids and provides a detailed description of anatomical traits in S. carvachoi. Studies that describe sexual systems in Alpheidae may shed light on the evolutionary history of gender expression in carideans and how environmental conditions favour sex allocation in decapods and other invertebrates. [ABSTRACT FROM AUTHOR]

Crustaceans possess a range of sensory organs crucial in sensory perception, communication, and various ecological functions. Understanding morphological and functional differences in antennae among species could validate taxonomic differentiation and ecological adaptations. The antennae morphology and ultrastructure of mud crab species within the Scylla genus are poorly understood, and their role in ecological adaptation and species differentiation remains unexplored. This study aimed to describe and compare the morphology and ultrastructure of antennae in Scylla olivacea, Scylla tranquebarica, and Scylla paramamosain. Antennae were carefully excised from each crab and subjected to morphological, morphometric, and ultrastructural analysis. The study revealed that the antennae of Scylla species exhibit similar overall morphology, with a series of segments that tapered toward the upper end. All species possess non‐branched single setae on the upper end of each segment. The number of antennae segments varied between species, with S. paramamosain having significantly more segments than S. olivacea. Additionally, the length and width of antenna segments differed among the species, with S. tranquebarica having a rougher antenna surface compared to S. olivacea and S. paramamosain. Our findings suggest that Scylla's antennae are distinct between species, especially in the number of segments and setae size. Such difference might be related to ecological adaptation. The role of antennae in sensory perception and social behavioral cues in mud crabs warrants further investigation. This study serves as a foundational reference for future research on the taxonomy, ecological adaptation, and sensory behaviors in the Scylla genus. Research Highlights: Variations and similarities in morphology and ultrastructure of three Scylla species can be found in the antennae.Scylla paramamosain had significantly higher number of segments than Scylla olivacea in morphology feature.The antennae surface of Scylla tranquebarica was rougher than that of S. olivacea and S. paramamosain.Antennae of three Scylla species possess non‐branched single setae. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) is prevalent in aquatic ecosystems and accumulates in various tissues of aquatic organisms, leading to severe biological toxicity. Selenium (Se) is recognized for mitigating heavy metal toxicity, though its protective effects against Cd in aquatic crustaceans remain underexplored. This study, therefore, assessed the effects of dietary Cd (15 mg/kg) exposure and Se (6 mg/kg) supplementation on the hepatopancreas and ovaries of female crayfish to uncover the mechanisms of Cd toxicity and the protective role of Se. The results showed that Cd accumulation in the hepatopancreas caused a reduced hepatopancreas index (HPI), decreased protein content, histopathological damage, and oxidative stress, while Se supplementation reduced Cd levels, mitigated damage, and restored tissue integrity and antioxidant defenses. Transcriptomic analysis further revealed significant alterations in gene expression related to detoxification, lipid metabolism, and energy production in response to Cd exposure, which were partially or fully restored by Se supplementation. Additionally, Se alleviated Cd-induced inhibition of ovarian development, as evidenced by improved ovary index, enhanced oocyte development, and normalization of essential trace element levels. Mechanistically, Se restored the Cd-disrupted vitellogenin (Vtg) synthesis in the hepatopancreas via regulating the mRNA expression of hsp70 and genes related to the molt-inhibiting hormone (MIH) (mih, rxr, and ecr). Overall, these findings indicate that Se supplementation mitigated Cd-induced hepatopancreatic dysfunction, restored Vtg synthesis, and consequently counteracted the inhibition of ovarian development in adult female crayfish.

Background Unrealistic model assumptions or improper quantitative methods reduce the reliability of data-limited fisheries assessments. Here, we evaluate how traditional length-based methods perform in estimating growth and mortality parameters in comparison with unconstrained bootstrapped methods, based on a virtual population and a case study of seabob shrimp (Xiphopenaeus kroyeri, Heller, 1862). Methods Size data were obtained for 5,725 seabob shrimp caught in four distinct fishing grounds in the Southwestern Atlantic. Also, a synthetic population with known parameter values was simulated. These datasets were analyzed using different length-based methods: the traditional Powell-Wetheral plot method and novel bootstrapped methods. Results Analysis with bootstrapped ELEFAN (fishboot package) resulted in considerably lower estimates for asymptotic size (L∞), instantaneous growth rate (K), total mortalities (Z) and Z/K values compared to traditional methods. These parameters were highly influenced by L∞ estimates, which exhibited median values far below maximum lengths for all samples. Contrastingly, traditional methods (PW method and Lmax approach) resulted in much larger L∞ estimates, with average bias >70%. This caused multiplicative errors when estimating both Z and Z/K, with an astonishing average bias of roughly 200%, with deleterious consequences for stock assessment and management. We also present an improved version of the length-converted catch-curve method (the iLCCC) that allows for populations with L∞ > Lmax and propagates the uncertainty in growth parameters into mortality estimates. Our results highlight the importance of unbiased growth estimates to robustly evaluate mortality rates, with significant implications for length-based assessments of data-poor stocks. Thus, we underscore the call for standardized, unconstrained use of fishboot routines.

Motor systems operate over a range of frequencies and relative timing (phase). We studied the role of the hyperpolarization-activated inward current (Ih) in regulating these features in the pyloric rhythm of the stomatogastric ganglion (STG) of the crab, Cancer borealis, as temperature was altered from 11°C to 21°C. Under control conditions, rhythm frequency increased monotonically with temperature, while the phases of the pyloric dilator (PD), lateral pyloric (LP), and pyloric (PY) neurons remained constant. Blocking Ih with cesium (Cs+) phase advanced PD offset, LP onset, and LP offset at 11°C, and the latter two further advanced as temperature increased. In Cs+ the frequency increase with temperature diminished and the Q10 of the frequency dropped from ~1.75 to ~1.35. Unexpectedly in Cs+, the frequency dynamics became non-monotonic during temperature transitions; frequency initially dropped as temperature increased, then rose once temperature stabilized, creating a characteristic ‘jag’. Interestingly, these jags persisted during temperature transitions in Cs+ when the pacemaker was isolated by picrotoxin, although the temperature-induced change in frequency recovered to control levels. Overall, these data suggest that Ih plays an important role in maintaining smooth transitory responses and persistent frequency increases by different mechanisms in the pyloric circuitry during temperature fluctuations.

While some streams have dense populations of aquatic detritivorous isopods, research on the colonization of leaf packs typically focuses on aquatic insects. To determine whether shifts in dominant local forest species might impact isopod populations, we placed leaf packs of red/sugar maple, American beech, and red oak on the substratum of riffles and pools in Cedar Creek (Allentown, PA, USA) in April 2019. We retrieved the packs after one week, re-deployed them, and re-collected them after two weeks of submersion, enumerating the number of isopods (Lirceus sp.) upon each retrieval. Surprisingly, neither the species of leaf nor the stream microhabitat significantly affected the number of isopods. However, the duration of leaf conditioning was important; significantly more isopods inhabited leaves after two weeks of submersion than after only one week. Maple and oak leaves displayed significantly more skeletonization after two weeks than the beech leaves, which remained intact. However, the similar numbers of isopods across leaf species suggest either the presence of acceptable, consumable microbial communities on all three species of leaves or that a tradeoff exists between the value of food and the importance of refuge provided by intact leaves.

While some streams have dense populations of aquatic detritivorous isopods, research on the colonization of leaf packs typically focuses on aquatic insects. To determine whether shifts in dominant local forest species might impact isopod populations, we placed leaf packs of red/sugar maple, American beech, and red oak on the substratum of riffles and pools in Cedar Creek (Allentown, PA, USA) in April 2019. We retrieved the packs after one week, re-deployed them, and re-collected them after two weeks of submersion, enumerating the number of isopods (Lirceus sp.) upon each retrieval. Surprisingly, neither the species of leaf nor the stream microhabitat significantly affected the number of isopods. However, the duration of leaf conditioning was important; significantly more isopods inhabited leaves after two weeks of submersion than after only one week. Maple and oak leaves displayed significantly more skeletonization after two weeks than the beech leaves, which remained intact. However, the similar numbers of isopods across leaf species suggest either the presence of acceptable, consumable microbial communities on all three species of leaves or that a tradeoff exists between the value of food and the importance of refuge provided by intact leaves. [ABSTRACT FROM AUTHOR]

Carotenoid cleavage oxygenases can cleave carotenoids into a range of biologically important products. Carotenoid isomerooxygenase (NinaB) and β, β-carotene 15, 15′-monooxygenase (BCO1) are two important oxygenases. In order to understand the roles that both oxygenases exert in crustaceans, we first investigated NinaB-like (EsNinaBl) and BCO1-like (EsBCO1l) within the genome of Chinese mitten crab (Eriocheir sinensis). Their functions were then deciphered through an analysis of their expression patterns, an in vitro β-carotene degradation assay, and RNA interference. The results showed that both EsNinaBl and EsBCO1l contain an RPE65 domain and exhibit high levels of expression in the hepatopancreas. During the molting stage, EsNinaBl exhibited significant upregulation in stage C, whereas EsBCO1l showed significantly higher expression levels at stage AB. Moreover, dietary supplementation with β-carotene resulted in a notable increase in the expression of EsNinaBl and EsBCO1l in the hepatopancreas. Further functional assays showed that the EsNinaBl expressed in E. coli underwent significant changes in its color, from orange to light; in addition, its β-carotene cleavage was higher than that of EsBCO1l. After the knockdown of EsNinaBl or EsBCO1l in juvenile E. sinensis, the expression levels of both genes were significantly decreased in the hepatopancreas, accompanied by a notable increase in the redness (a*) values. Furthermore, a significant increase in the β-carotene content was observed in the hepatopancreas when EsNinaBl-mRNA was suppressed, which suggests that EsNinaBl plays an important role in carotenoid cleavage, specifically β-carotene. In conclusion, our findings suggest that EsNinaBl and EsBCO1l may exhibit functional co-expression and play a crucial role in carotenoid cleavage in crabs. [ABSTRACT FROM AUTHOR]

The holobiont theory expands the notion of individual multicellular organisms as a community composed of a host and all its associated microorganisms. This concept has been extensively studied in the field of aquaculture, where increasing evidence has highlighted the importance of the host associated microorganisms in species fitness. Here, we focus our review on mollusc and crustacean species in which microbiota dysbiosis has recently been described in the context of various diseases, resulting in significant economic losses. Influencing the holobiont structure through the use of probiotics is a potential strategy that could improve the fitness or the robustness of cultivated species. We discuss here the possibility of developing microbiome targeted prophylactic approaches by promoting (1) methods to identify host microbial community that fosters good health status and (2) early life microbial education to favour long‐term resistance to stress or disease. This review aims to inform the aquaculture industry about potential strategies in rearing practices to mitigate diseases and economic losses. [ABSTRACT FROM AUTHOR]

Tropical rock lobsters (Panulirus ornatus) are a highly cannibalistic species with intermoult animals predominantly attacking animals during ecdysis (moulting). Rapid, positive characterisation of pre-ecdysis lobsters may open a pathway to disrupt cannibalism. Ecdysial suture line development is considered for pre-ecdysis recognition with suture line definition compared for intermoult and pre-ecdysis lobsters emerged and immerged, using white, near ultraviolet (365 nm), near infrared (850 nm), and specialty SFH 4737 broadband IR LEDs against a reference of intermoult lobsters with no suture line development. Difficulties in acquiring suture line images prompted research into pre-ecdysis characterisation from the lobster's dorsal carapace, due to its accessibility through a culture vessel's surface. In this study, a novel low-cost spectral camera was developed by coordinating an IMX219 image sensor, an AS7265x spectral sensor, and four SFH 4737 broadband infrared LEDs through a single-board computer. Images and spectral data from the lobster's dorsal carapace were acquired from intermoult, pre-ecdysis, and post-ecdysis lobsters. For the first time, suture line definition was found to be enhanced under 850 nm, 365 nm, and SFH 4737 LEDs for immerged lobsters, while the 850 nm LED achieved the best suture line definition of emerged lobsters. Although the spectral camera was unable to characterise pre-ecdysis, its development was validated when a least squares regression for binary classification decision boundary successfully separated 86.7% of post-ecdysis lobsters. Achieving post-ecdysis characterisation is the first time the dorsal carapace surface has been used to characterise a moult stage for palinurid lobsters. [ABSTRACT FROM AUTHOR]

Social aggregative behaviour may have evolved in marine isopods to aid hunting, and help the animals protect themselves from predation. This social behaviour could have assisted some isopod species to make the evolutionary transition from marine to terrestrial environments, as aggregative huddling of isopods on land reduces desiccation when out of water. To determine if the common pill-bug Armadillidium vulgare demonstrates social behaviour, groups of animals were filmed for 60 min in an arena that contained a binary choice of two shelters. This experiment was directly repeated with the same specimens three more times in the same day and this series of four experimental runs was replicated a total of 10 times with a different group of animals for each of the 10 series. In most cases, the majority of specimens chose one of the two identical shelters at random, and congregated under this winning shelter. The amount of animals that congregated under the winning shelter, however, significantly decreased over the four consecutive runs, whereas the amount of animals that congregated under the losing shelter significantly increased with prior experience. These data indicate that A. vulgare is a social animal but this social behaviour can decrease with exposure to the novel environment. This attenuation in social behaviour may serve to decrease the drive to join the larger of the two groups in an area where a danger from predation has not been encountered and allow experienced animals to explore new terrain. [ABSTRACT FROM AUTHOR]

The Thai freshwater shrimps of the family Atyidae are reviewed. A taxonomic synopsis is given here to the 19 species so far known from Thailand, including two new species, namely Caridina thai sp. nov. and C. kottelati sp. nov. Two species are recorded for the first time from Thailand, namely C. annandalei , and C. rangoona. Caridina siamensis is resurrected and regarded as senior synonym for C. villadolidi. Most of the landlocked species found in Thailand are endemic to the regions of Indo-China (Caridina annandalei , C. lanceifrons , C. macrophora , C. rangoona , and C. tonkinensis) or Sundaland (C. johnsoni and C. temasek). Apart from the recently described C. panhai and the two new species, C. gracilima is the only confirmed endemic species for Thailand. Descriptions for new and poorly known species, diagnosis for newly recorded species and taxonomic discussions for all species are provided. [ABSTRACT FROM AUTHOR]

Seafood allergens have emerged as a significant concern in recent years, given the rising prevalence of allergic reactions associated with the consumption of various seafood products. Seafood allergens encompass a diverse range of proteins found in fish and shellfish, with some species more likely to trigger allergic reactions than others. The complexity of seafood allergens stems from their structural diversity and the potential for cross-reactivity with allergens from related or even unrelated species. These tests, such as enzyme-linked immunosorbent assays and molecular assays are essential for both allergen detection in food products and the diagnosis of seafood allergies in individuals. [ABSTRACT FROM AUTHOR]

Marine Protected Areas limit fishing to protect a broad range of species and enhance biodiversity. Consequently, closures may not benefit species equally and species‐specific assessments are required to determine the impact of closures.Relative abundance and size of Giant Mud Crab (Scylla serrata) was compared across no‐take and fished zones in Port Stephens‐Great Lakes Marine Park, on the temperate east coast of Australia (32.45°S). In addition, passive acoustic telemetry was used to estimate daily space‐use areas.Similar abundances were observed between no‐take and fished zones; however certain no‐take sites had higher abundances than others. In addition, crabs were 9.9 mm larger in no‐take zones on average. Daily crab space‐use varied widely (~4 to 1000 m2), and generally increased with water temperature and conductivity.These patterns indicate that recruitment processes interact with marine park protection to shape crab abundances across estuaries. However no‐take zoning appears to primarily limit fishing mortality on legal size crabs (i.e., carapace length >85 mm) resulting in larger crabs within no‐take zones. This may mean no‐take zones enhance reproductive output of crab populations since larger individuals are likely to be more fecund. [ABSTRACT FROM AUTHOR]

Coating crayfish (Astacus leptodactylus) meat samples with chitosan solution could be an effective approach to limit microbiological spoilage. During the 18-day cold storage period at 2°C±1, mesophilic aerobic bacteria (MABc), psychrophilic bacteria (PBc), yeast mold count (YMc), anaerobic bacteria (AnBc), and Enterobacteriaceae growth in the samples coated with chitosan (0.5% and 1%) and also control group samples were tested. Crayfish samples coated with chitosan (0.5% and 1%) had a lower TMABc (6.58 to 4.60 log CFU/g: up to 30.09%), TPBc (3.77 to 1.99 log CFU/g: up to 47.21%), TYMc (1.84 to 1.27 log CFU/g: up to 30.97%), TAnBc (3.69 to 1.88 log CFU/g: up to 49.05%), and Enterobacteriaceae (3.49 to 2.60 log CFU/g: up to 25.50%) counts as compared with control group samples at 2°C±1. The results particularly based on mesophilic anaerobic bacteria suggested that the application would be a promising approach to limit microbial growth and provide food safety for boiled crayfish meat samples. [ABSTRACT FROM AUTHOR]

The supply of coconut crabs (Birgus latro Linnaeus, 1767) has been sourced from capture in the wild. Development efforts in aquaculture have succeeded in producing eggs. However, further development with larval maintenance failed because it was constrained by a low survival rate. This study aimed to identify the potential probiotic bacteria in coconut crabs. Coconut crab samples were collected from Moor Island, South Patani District, Central Halmahera Regency, North Maluku Province, Indonesia. The intestines of coconut crabs were taken as much as 1 g, then ground on a porcelain dish and added to Tri-Salt. The scouring liquid was taken in 0.1 ml and spread on a petri dish containing Nutrient Agar. The isolated used were marked with BL1, BL2, BL3, BL4, and BL5. Molecular identification was performed with sequencing and then analyzed using the Basic Local Alignment Search Tool (BLAST). The selection of isolates from the gastrointestinal tract of coconut crabs showed that the bacteria obtained were Enterobacter tabaci (BL1), Enterobacter hormaechei (BL2), Bacillus horneckiae (BL3), Pseudomonas stutzeri (BL4), and Acinetobacter variabilis (BL5). Further testing revealed that the bacteria A. variabilis (BL5) is a probiotic isolate in coconut crabs. [ABSTRACT FROM AUTHOR]

Chitosan is a derivative of chitin that is one of the most abundant biopolymers in nature, found in crustacean shells as well as in fungi cell walls. Most of the commercially available chitosans are produced from the exoskeletons of crustaceans. The extraction process involves harsh chemicals, has limited potential due to the seasonal and limited supply and could cause allergic reactions. However, chitosan has been shown to alleviate the negative effect of environmental stressors in plants, but there is sparse evidence of how chitosan source affects this bioactivity. The aim of this study was to investigate the ability of chitosan from mushroom in comparison to crustacean chitosan in enhancing drought stress tolerance in tomato plants (cv. MicroTom). Chitosan treatment was applied through foliar application and plants were exposed to two 14-day drought stress periods at vegetative and fruit set growth stages. Phenotypic (e.g., fruit number and weight), physiological (RWC) and biochemical-stress-related markers (osmolytes, photosynthetic pigments and malondialdehyde) were analyzed at different time points during the crop growth cycle. Our hypothesis was that this drought stress model will negatively impact tomato plants while the foliar application of chitosan extracted from either crustacean or mushroom will alleviate this effect. Our findings indicate that drought stress markedly decreased the leaf relative water content (RWC) and chlorophyll content, increased lipid peroxidation, and significantly reduced the average fruit number. Chitosan application, regardless of the source, improved these parameters and enhanced plant tolerance to drought stress. It provides a comparative study of the biostimulant activity of chitosan from diverse sources and suggests that chitosan sourced from fungi could serve as a more sustainable and environmentally friendly alternative to the current chitosan from crustaceans. [ABSTRACT FROM AUTHOR]

Crustacean feeding morphology and postprandial nutrient processing is a highly size‐selective procedure. The digestive system of lobsters is predicated on grinding feed to a fine particle size before digestion. Therefore, fine pregrinding of raw materials may bypass the need for extensive grinding in the proventriculus and expedite digestive and absorptive processes. Panulirus ornatus juveniles (N = 56) were allocated to four feed groups (n = 14). Groups A, B and C were fed nutritionally identical feeds featuring raw materials ground to 1000 µm (Feed A), 500 µm (Feed B) and 200 µm (Feed C) while the fourth group (Group S) acted as a 24‐h nonfeeding baseline control group. Sequential postprandial haemolymph extractions were performed at 0.5, 1, 1.5, 2, 3.5, 5.5 and 24 h across treatment groups. Haemolymph samples were assessed and analysed for brix (%), total proteins (g L–1), glucose (mmol L–1) and cholesterol (mmol L–1). Brix was found to have significant positive correlations with all the haemolymph biochemical properties while no significant correlations were identified between individual lobster size and haemolymph properties. Analysis of deviance applied to mixed effects models did not identify significant differences in haemolymph properties across feed groups. Trends identified here are indicative of diurnal rhythm patterns, likely orchestrated by the release of the crustacean hyperglycaemic hormone (CHH) when anticipating a meal. Additionally, the use of brix values, may not be optimal for identifying postprandial trends, yet could remain a valid indicator of longer‐term nutritional status. [ABSTRACT FROM AUTHOR]

Objective: Recent estimates of the North Carolina blue crab Callinectes sapidus stock found that the stock is overfished and overfishing is occurring. Threats outlined in the 2018 stock assessment include climate change and estrogenic endocrine‐disrupting chemicals (EEDCs). The objective of this study was to use an individual‐based modeling approach to simulate the long‐term effects of climate change and EEDCs on the North Carolina blue crab stock. Methods: To do this, we built an individual‐based model that simulated the life history of individual blue crabs, including but not limited to growth, reproduction, and mortality. We then tested our population of blue crabs against 30 different combinations of temperature and EEDC scenarios over 50 years to determine the long‐term effects on the population. Result: Our simulations suggested that the North Carolina blue crab population may be relatively resilient to climate change‐related temperature shifts but that there may be significant impacts at the population level as summer temperatures become more extreme. Endocrine‐disrupting chemical effects resulted in an alternative stable state of lower catch or the total extinction of the population. Conclusion: These results suggest that management strategy changes may be necessary as temperatures become more extreme in the region. In addition, more research is necessary to fully understand the effects of EEDCs on blue crabs and other crustaceans at the individual and population level. Impact statementThis study used a novel approach to connect fine‐scale blue crab ecology to broadscale population ecology. This model can be a useful predictive tool that allows for assessment of the effects of future threats or regulation changes and can be modified to simulate other important crustacean species. [ABSTRACT FROM AUTHOR]

ABSTRACT An eco-friendly method of extraction for chitin and chitosan extracted from crawfish was our goal. Chitin is always present with proteins, minerals, and other components. This study used an eco-accommodating, novel technique for chitin and chitosan extraction. Lactobacillus lactis was used for the deproteinization and demineralization of chitin in a single stage by Saccharomyces cerevisiae (BB: biological-biological extraction) to convert chitin into chitosan. BB is a more environmentally friendly method of producing chitosan than deacetylation with NaOH (BC: biological-chemical extraction). Chitosan was characterized by FTIR. A high degree of deacetylation (%) was observed. The UV spectrum for chitosan was similar at 0.788, 0.415, and 1.150 for CC, BC, and BB, respectively. The results show that chitosan (BB) has potential applications in the biomedical fields such as antioxidant activity, anticancer activity against human liver cancer (HepG2), breast cancer (MCF-7) and human hepatocellular carcinoma (HCT) cell lines. The results in terms of water treatment and removal of dyes using chitosan (BB) are valuable in terms of its application in industrial wastewater treatment and demonstrate that it can be used as a biosorbent.

A documented checklist of the Crustacea (Stomatopoda, Decapoda) is provided for the southern Guianas region (sGuianas), a homogeneous ecoregion including Guyana, Suriname, French Guiana and the Brazilian State of Amapá. The history of crustacean collections undertaken there between 1759 and 2022 is summarized. In total, 529 species are listed. Biodiversity varies between countries: 165 species in Guyana; 317 in Suriname, 343 in French Guiana, and 315 in Brazil Amapá, as a direct result of different sampling efforts. There are 22 Stomatopoda and 507 Decapoda, ranked by numerical diversity as Brachyura (206), Caridea (113), Anomura (85), Dendrobranchiata (67) and others (36). The list is analyzed with the species classified by major biotopes, distinguishing those from freshwater, mangroves and estuaries, and frankly marine environments. Regional comparisons are made in the Western Atlantic showing that the sGuianas marine fauna is depauperate compared to that of other regions. This is explained by the influence of the Amazon River plume, carrying desalinated water and fine sediments, which leads to the reduction of coral reef formations in sGuianas. Only a few species of freshwater crabs (genera Kunziana and Microthelphusa) are endemic to the region. The pace of species discovery over the years indicates that the sGuianas fauna remains still imperfectly known and that probably more than 600 species are present in the region.

Abstract Subterranean and surface habitats are in stark contrast in several environmental factors. Therefore, adaptation to the subterranean environment typically impedes the (re)colonisation of surface habitats. The genus Niphargus includes amphipod crustaceans that primarily occupy subterranean habitats. All its species show typical adaptations to the subterranean environment. However, some Niphargus species occur in surface‐subterranean ecotones. To understand whether (i) habitat‐based phenotypic divergence is present between the cave and the ecotone species and (ii) similar phenotypes emerge independently in each ecotone, we studied morphological divergence between four cave and four ecotone Niphargus species based on 13 functional morphological traits. To account for different selection acting on the sexes, we included both males (N = 244) and females (N = 222). Nine out of 13 traits showed habitat‐divergence. Traits related to feeding and crawling were shorter, while traits related to oxygenation were larger in ecotone species. Eleven out of 13 traits were sexually dimorphic. Traits related to oxygenation and crawling were larger in females, while the trait related to swimming was larger in males. We found that the extent of sexual dimorphism differs between the habitats in eight traits related to sensing, feeding, oxygenation and crawling. Additionally, we found that in certain traits related to sensing and oxygenation, habitat‐related differences are only present in one sex, but not the other. We conclude that the detected differences between the cave and the ecotone species indicate divergent evolution, where similarities among the different species within habitat type indicate convergent evolution. The high degree of sexual dimorphism paired with differences in sexual dimorphism between the habitats in certain traits suggest that sexual and fecundity selections have comparable effects to environmental selection. Thus, studies of habitat‐dependent adaptations investigating one sex only, or not considering sexual dimorphism, can lead to erroneous conclusions.

In shrimp farming, the use of commercial feed can generate high nutrient loads in water bodies, and often constitute the most substantial component of production costs. Alternatives that seek to reduce the use of commercial feed can therefore both mitigate environmental impacts and reduce operational expenses. One possible strategy is incorporation of algae that crustaceans can consume with minimal biological effect into integrated multi-trophic aquaculture (IMTA) systems. Our objective was to determine whether the marine shrimp Penaeus vannamei feeds on the fresh macroalga Chaetomorpha clavata and whether the partial substitution (50 %) of this alga in its diet influences its physiology. Survival, growth, and a range of physiological processes including ingestion, defecation, metabolism, nitrogen excretion, oxidized energy substrate, hepatosomatic index, and energy budget were assessed in P. vannamei shrimp fed commercial feed (100 %, control) versus shrimp fed a combination of commercial feed and algae (50 % each). Our results showed that P. vannamei fed on C. clavata, and that there were no significant differences in mortality and growth rates (∼11 %) between shrimp fed with the two diets. The ingestion rate was higher in the group fed with macroalgae, however the defecation rate and digestibility were not affected. In both groups, no differences were detected in metabolic rates, growth, nitrogenous excretion, and egestion between shrimp fed the different diets, nor in oxidized energy substrates and the hepatosomatic index. Our results show that substituting 50 % of the feed with C. clavata represents a viable alternative to full commercial feed since it had minimal impact on the physiological functions of P. vannamei. In addition to the economic benefit of reducing the amount of feed used during culture, the use of algae also reduces contamination of effluent water, thereby improving environmental sustainability and water quality.

American lobsters (Homarus americanus) stored in open tidal pounds can develop impoundment shell disease (ISD), resulting in decreased marketability of the lobsters on the live market. Little is known about ISD or the immunological responses of lobsters exhibiting this disease. The objective of this project was to identify genes from H. americanus hepatopancreas that are differentially expressed in response to ISD. Lobsters were separated into asymptomatic, moderately symptomatic, and severely symptomatic groups, which represent animals with 0%, 5%–20%, and >20% lesion coverage of the carapace, respectively. RNA-seq analysis found that 134 genes were differentially expressed between groups (false discovery rate (FDR)

The signal crayfish Pacifastacus leniusculus is one of the most widespread non-indigenous crayfish in Europe and is of interest to aquaculture in many countries. Once they escape into the wild, they disperse and become a potential source of food exploited for consumption by local inhabitants. The ingestion of plastics by the invasive signal crayfish in the Wieprza River, a tributary to the Baltic Sea, was determined by the FTIR identification of plastic compounds found in stomachs. The occurrence of plastic debris in the stomachs of P. leniusculus is reported for the first time. Plastic particles with the size range between 70 and 450 µm were observed only among crayfish inhabiting the lower, urbanized part of the river (7.3% of specimens). The presence of PTFE (polytetrafluoroethylene), cellophane, PP (polypropylene), PE (polyethylene), PMMA (polymethyl methacrylate), and nylon was confirmed with the highest frequency of PTFE in the stomachs of crayfish. Fibres were the predominant type of microplastics in crayfish stomachs. The results indicated the size-selective uptake and ingestion of plastics depending on the traits of the species and environment. [ABSTRACT FROM AUTHOR]

The first evidence of the predation of brittle stars, Ophiothela sp. (Ophiotrichidae), by the palaemonid shrimp Phyllognathia simplex Fujino, 1973 (Palaemonidae), is presented based on a single observation accompanied by in situ photographs taken while scuba diving in Bali, Indonesia, also being the first ever observation of the feeding behaviour in this uncommon shrimp species. In addition, in situ photographs of three ovigerous females tentatatively identified as P. cf. simplex from southern Florida, U.S.A., suggest that P. simplex or a closely related species may be present in the western Atlantic. This is the first photographic evidence of the presence of the genus Phyllognathia Borradaile, 1915 in this part of the world. [ABSTRACT FROM AUTHOR]