Decapoda Research Articles

Among-individual behavioural variation in the ornamental red cherry shrimp, Neocaridina heteropoda.

Personality variation, defined as among-individual differences in behaviour that are repeatable across time and context, is widely reported across animal taxa. From an evolutionary perspective, characterising the amount and structure of this variation is useful since differences among individuals are the raw material for adaptive behavioural evolution. However, behavioural variation among individuals also has implications for more applied areas of evolution and ecology-from invasion biology to ecotoxicology and selective breeding in captive systems. Here, we investigate the structure of personality variation in the red cherry shrimp, Neocaridina heteropoda, a popular ornamental species that is readily kept and bred under laboratory conditions and is emerging as a decapod crustacean model across these fields, but for which basic biological, ecological and behavioural data are limited. Using two assays and a repeated measures approach, we quantify behaviours putatively indicative of shy-bold variation and test for sexual dimorphism and/or size-dependent behaviours (as predicted by some state-dependent models of personality). We find moderate-to-high behavioural repeatabilities in most traits. Although strong individual-level correlations across behaviours are consistent with a major personality axis underlying these observed traits, the multivariate structure of personality variation does not fully match a priori expectations of a shy-bold axis. This may reflect our ecological naivety with respect to what really constitutes bolder, more risk-prone, behaviour in this species. We find no evidence for sexual dimorphism and only weak support for size-dependent behaviour. Our study contributes to the growing literature describing behavioural variation in aquatic invertebrates. Furthermore, it lays a foundation for further studies harnessing the potential of this emerging model system. In particular, this existing behavioural variation could be functionally linked to life-history traits and invasive success and serve as a target of artificial selection or bioassays. It thus holds significant promise in applied research across ecotoxicology, aquaculture and invasion biology.

Bacteria-Driven Fossil Ecosystems as Paleoindicators of Active Continental Margins and the Role of Carbonate Sediment-Hosted Vents in Geodynamic Reconstructions

Continental rifting of the Tisza microplate started during the Late Jurassic and resulted in phreatic eruptions, peperite, and the construction of a volcanic edifice in the Early Cretaceous in the Mecsek Mountains (South Hungary). In the SE direction from the volcanic edifice at Zengővárkony, a shallow marine (depth 100–200 m) carbonate sediment hosted a vent environment, and iron ore deposition occurred at the end of the Valanginian to early Hauterivian, hosting a diverse, endemic fauna of approximately 60 species. The detailed mineralogical analysis of the transport conduits included Fe oxides (ferrihydrite, goethite, hematite, and magnetite), quartz, mixed carbonate, pyrite, feldspar, Fe-bearing clay minerals, apatite, sulfates (barite, gypsum, and jarosite), and native sulfur. Filamentous, microbially mediated microtextures with inner sequented, necklace-like spheric forms (diameter of 1 μm) and bacterial laminae are also observed inside decapod crustacean coprolites (Palaxius tetraochetarius) and in the rock matrix. This complex ecological and mineralogical analysis provided direct evidence for the presence of bacteria in fossil sediment-hosted vent (SHV) environments on the one hand and for the intimate connection between bacteria and decapod crustaceans in hydrothermal environments 135 Ma before. This observation completes the fossil food chain of chemosynthesis-based ecosystems, from primary producers to the top carnivores reported for the first time from this locality.

Diversity of decapod crustaceans in a neotropical coastal lagoon interconnected with the sea/estuary

Coastal lagoons are aquatic environments that are located at the coast-sea interface. Ecologically important, they harbor a high abundance of macroinvertebrates, especially decapod crustaceans. Therefore, the present study investigated the influence of physical factors on the diversity of decapod macrocrustaceans in a Neotropical coastal lagoon and prepared a list of species, with emphasis on new occurrences for this habitat. The study was conducted from January/2013 to January/2014 in a Neotropical coastal lagoon, seasonally connected to the sea. Ecological indices were estimated to understand biotic diversity; in addition, correlations and type II regression were performed on bivariate combinations to assess the degree of interaction between biotic vs. abiotic variables related to lagoon hydrodynamics. Finally, a partial least squares regression was performed to assess such relationships in the multivariate scenario. Field observations revealed a period of interconnection between the lagoon and the sea/estuary in March and complete isolation in October. The most abundant taxa were Penaeus sp., Callinectes sp., C. danae, Pagurus criniticornis and Clibanarius sclopetarius. In the month before total isolation, greater general abundance was recorded, and in the following month, greater diversity, dominance and equitability were recorded. In the multivariate model, only Maximum Wind Gust, Hourly Wind Speed and Minimum Monthly Astronomical Tide were relevant to explain the biotic variations in the lagoon. These results demonstrate that wind and tide can act as proxies for the hydrodynamic analysis of the lagoon in relation to the biotic factors investigated, since they promote seasonal events of opening and isolation of connectivity, contributing to the transport of individuals by carrying water masses. Still, the coastal lagoon presented itself as a place of shelter and foraging for the biota, with emphasis on the genera Penaeus and Callinectes that use the lagoons to complete their life cycle in the sea-estuary transition. This study indicates that coastal lagoons are essential for the life cycle of coastal crustaceans and should be included in management actions to conserve these areas and Neotropical crustacean species.

The Effects of Caustic Soda and Benzocaine on Directed Grooming to the Eyestalk in the Glass Prawn, Palaemon elegans, Are Consistent with the Idea of Pain in Decapods

Acceptance of the possibility of pain in animals usually requires that various criteria are fulfilled. One such criterion is that a noxious stimulus or wound would elicit directed rubbing or grooming at the site of the stimulus. There is also an expectation that local anaesthetics would reduce these responses to damage. These expectations have been fulfilled in decapod crustaceans but there has been criticism of a lack of replication. Here, we report an experiment on the effects of a noxious chemical, sodium hydroxide, applied to one eyestalk of the glass prawn. This caused an immediate escape tail-flick response. It then caused nipping and picking with the chelipeds at the treated eyestalk but much less so at the alternative eyestalk. Prior treatment with benzocaine also caused an immediate tail-flick and directed behaviour, suggesting that this agent is aversive. Subsequently, however, it reduced the directed behaviour caused by caustic soda. We thus demonstrated responses that are consistent with the idea of pain in decapod crustaceans.

Prevalence of white spot syndrome virus (WSSV) in wild-caught and commodity decapod crustaceans in coastal South Carolina, USA

Abstract White spot syndrome virus (WSSV) is a highly contagious and economically costly virus that affects many crustacean species. Since its introduction into the United States in the 1990s, it has spread from aquaculture shrimp and crayfish to wild crustaceans throughout the southeastern United States. Transmission to natural systems may occur through contact between commodity (i.e., store-bought) and wild crustaceans or the use of infected frozen shrimp as bait, which has been proven capable of transmitting the virus. In this study, we surveyed both live (Penaeus setiferus (Linnaeus, 1767) and P. aztecusIves, 1891) and frozen commodity shrimp (Penaeus vannameiBoone, 1931) and crayfish (Procambarus troglodytes (Le Conte, 1856) and P. clarkii (Girard, 1852)) as well as wild populations of some of these species of shrimp, crayfish, and blue crabs (Callinectes sapidusRathbun, 1896) in South Carolina for WSSV. We found extremely low levels of the virus in wild-caught decapods but high levels of WSSV in commodity crayfish (50%) and imported frozen shrimp (43.3%). While additional work is needed to understand the environmental conditions that affect the transmission potential of WSSV, these results suggest that care must be taken with commodity crustaceans to prevent introductions of WSSV and subsequent harm to natural ecosystems.

First Record of Sarsia tubulosa (M. Sars, 1835) (Cnidaria, Hydrozoa) on Red King Crabs in the Coastal Barents Sea

Sarsia tubulosa (M. Sars, 1835), a colonial hydrozoan of the family Corynidae, is common in the Barents Sea. This study provides new evidence that the species acts as an epibiont of the red king crab Paralithodes camtschaticus, a non-indigenous but remarkably abundant decapod crustacean of immense commercial value in the coastal regions of the sea. This finding adds to the current collection of identified epibionts on the red king crab and highlights the prospect of ongoing symbiotic relationships between the crab and the regional fauna. We also provide photographic evidence of S. tubulosa colonies and a comparative morphological evaluation with another closely related corynid, Coryne hincksi Bonnevie, 1898, previously found on the red king crab. The main differences between these two species are the location of the gonophores (reproductive organs) on the hydranths and the final stage of their development: in the form of free-floating medusae (S. tubulosa) or remaining sessile as sporosacs (C. hincksi). Other distinguishing features include variations in hydranth morphology, number and arrangement of tentacles, and structural development of gonophores.

Tail Fan Necrosis syndrome in decapod crustaceans: A review.

Lobsters and crayfish in Australasia can develop a condition known as Tail Fan Necrosis (TFN syndrome). Many attempts have been made to find a primary pathogen or link the syndrome to commercial activities, but a solution remains elusive. TFN syndrome is a 'wicked problem', a problem difficult or impossible to solve because of incomplete and contradictory information forming a matrix of potential outcomes with no simple solution. Reviewing the literature shows TFN syndrome is sometimes reported to develop in association with sterile blisters on the telson and uropods which may rupture permitting invasion by environmental fungal and/or bacterial flora. Whether blisters form prior to, or because of, infection is unknown. TFN syndrome sometimes develops in captivity, sometimes requires a previous insult to the telson and uropods, and prevalence is patchy in the wild. The literature shows the cause of blisters associated with TFN syndrome remains an enigma, for which we suggest several possible initiating factors. We strongly urge that researchers not 'jump to conclusions' as to the aetiology of TFN syndrome. It cannot be explained without carefully exploring alternative aetiologies whilst being cognisant of the age-old lesson that 'correlation does not equal causation'.

In silico analysis of crustacean hyperglycemic hormone family G protein-coupled receptor candidates.

Ecdysteroid molting hormone synthesis is directed by a pair of molting glands or Y-organs (YOs), and this synthesis is inhibited by molt-inhibiting hormone (MIH). MIH is a member of the crustacean hyperglycemic hormone (CHH) neuropeptide superfamily, which includes CHH and insect ion transport peptide (ITP). It is hypothesized that the MIH receptor is a Class A (Rhodopsin-like) G protein-coupled receptor (GPCR). The YO of the blackback land crab, Gecarcinus lateralis, expresses 49 Class A GPCRs, three of which (Gl-CHHR-A9, -A10, and -A12) were provisionally assigned as CHH-like receptors. CrusTome, a transcriptome database assembled from 189 crustaceans and 12 ecdysozoan outgroups, was used to deorphanize candidate MIH/CHH GPCRs, relying on sequence homology to three functionally characterized ITP receptors (BNGR-A2, BNGR-A24, and BNGR-A34) in the silk moth, Bombyx mori. Phylogenetic analysis and multiple sequence alignments across major taxonomic groups revealed extensive expansion and diversification of crustacean A2, A24, and A34 receptors, designated CHH Family Receptor Candidates (CFRCs). The A2 clade was divided into three subclades; A24 clade was divided into five subclades; and A34 was divided into six subclades. The subclades were distinguished by conserved motifs in extracellular loop (ECL) 2 and ECL3 in the ligand-binding region. Eleven of the 14 subclades occurred in decapod crustaceans. In G. lateralis, seven CFRC sequences, designated Gl-CFRC-A2α1, -A24α, -A24β1, -A24β2, -A34α2, -A34β1, and -A34β2, were identified; the three A34 sequences corresponded to Gl-GPCR-A12, -A9, and A10, respectively. ECL2 in all the CFRC sequences had a two-stranded β-sheet structure similar to human Class A GPCRs, whereas the ECL2 of decapod CFRC-A34β1/β2 had an additional two-stranded β-sheet. We hypothesize that this second β-sheet on ECL2 plays a role in MIH/CHH binding and activation, which will be investigated further with functional assays.

Substrate Interactions and Free-Swimming Dynamics in the Crayfish Escape Response.

The caridoid or "tail flip" escape behavior of decapod crustaceans is a model system in neurobiology, but many aspects of its biomechanics are not well understood. To understand how the freshwater virile crayfish Faxonius virilis interacts with the substrate during the tail flip, we studied tail-flip hydrodynamics and force generation for free-moving animals standing on substrate, as well as tethered animals held at different distances from the substrate. We found no significant differences in force generation when distance from substrate was varied. Particle image velocimetry revealed that vortex formation was similar at all distances, but there were notable differences in interactions between shed vortices and substrate at different distances. Negative vorticity (clockwise flow of water) was observed in tethered animals interacting with the substrate but was largely absent in free-swimming animals. We found no evidence of ground effects enhancing tail flip performance in either tethered or free-swimming individuals, as peak force generation occurred before vortex shedding. This study contributes to our understanding of the crayfish escape response and highlights the need for more work that incorporates free-swimming animals and complex environments in the study of crustacean biomechanics.

Infection of Norway lobster (Nephrops norvegicus) by the parasite Hematodinium sp.: insights from 30 years of field observations.

The Norway lobster, Nephrops norvegicus, is an important representative of the benthos and also supports valuable fisheries across Europe. Nephrops are susceptible to infection by Hematodinium sp., an endoparasitic dinoflagellate that causes morbidity and mortality. From an epizootiological perspective, the Clyde Sea Area (CSA; west of Scotland) is the best-studied Hematodinium-Nephrops pathosystem, with historical data available between 1988 and 2008. We have revisited this pathosystem by curating and updating prevalence values, differentiating host traits associated with disease exposure and progression, and comparing Hematodinium sp. disease dynamics in the CSA to other locations and to other decapod hosts (Cancer pagurus, Carcinus maenas). Prevalence from a 2018/2019 survey (involving 1739 lobsters) revealed Hematodinium sp. still mounts a synchronized patent infection in the CSA; hence this pathogen can be considered as enzootic in this location. We highlight for the first time that Nephrops size is associated with high severity infection, while females are more exposed to Hematodinium sp. More generally, regardless of the host (Norway lobster, brown and shore crabs) or the geographical area (Ireland, Wales, Scotland), Hematodinium sp. patent infections peak in spring/summer and reach their nadir during autumn. We contend that Hematodinium must be considered one of the most important pathogens of decapod crustaceans in temperate waters.

Late Oligocene decapod crustaceans from the Trbovlje Formation of Slovenia, with a description of two new species of hymenosomatid crabs

Late Oligocene decapod crustaceans from the Trbovlje Formation of Slovenia, with a description of two new species of hymenosomatid crabs

Brazilians' perception of shrimp sentience and welfare

With the increase in research aimed at improving the welfare of animals raised in production systems and the recognition of sentience in decapod crustaceans, the welfare of shrimp has become a cause for concern. In shrimp farming, practices contrary to the principles of animal welfare are used and largely unknown to the consuming public. This study aimed to assess the views of Brazilians on the importance of incremental animal welfare improvements in shrimp farming, considering the social and cultural aspects of the respondents. To this end, 300 adult Brazilian participants answered questions on welfare, sentience, and eyestalk ablation of shrimp. Among the respondents, 75.7% expressed concern about the welfare of shrimp, believing that they can experience fear (63.0%), pain (84.0%), and pleasure (47.7%). The latter finding suggests a relative reluctance to recognize positive feelings in shrimp. Regarding eyestalk ablation, 81.7% of respondents were unaware of the procedure, but after a brief explanation, 81.3% considered it unacceptable, with 84.0% believing that shrimps suffer from the practice. Most respondents associated terms such as "painful, cruel, suffering, mercantilist, disrespectful, and mutilating" with the practice of ablation. Furthermore, by using Pearson's chi-square test, it was observed that gender, age, region, education, socio-economic status, profession, and frequency of consumption may be related to the respondents' opinions about shrimp welfare and their perception of shrimp sentience. Therefore, by recognizing that public concern drives changes in production methods, increasing knowledge about shrimp sentience and farming practices can help advance socially acceptable methods.

A review and synthesis of the benefits, drawbacks, and considerations of using traps to survey fish and decapods

Abstract Traps (or pots) are one of the oldest and most widespread scientific survey gears for fish and decapod crustaceans around the world. Here, I review and synthesize the extensive scientific literature describing the various benefits and drawbacks of using traps as a survey gear in scientific studies. The widespread use of traps in fish and decapod surveys is due to several characteristics like their low cost, flexible design, ease of use, ability to fish unattended, and being amenable to pairing with other gears. However, there are a number of significant drawbacks of using traps, including highly variable catches due to environmental fluctuations or behavioral interactions or lost traps that continue catching and killing animals, that must be considered and accounted for when initiating trap surveys. This study highlights the types of habitats and species most and least suited for monitoring by traps, and emphasizes the importance of matching the goals and objectives of a trap survey with the correct trap design, mouth entrance, bait type, soak time, and pairing of gears. Pilot studies are also recommended before surveys are initiated to quantify the selectivity patterns of traps and identify the various factors that may influence trap catch.

Trends in the decapod crustacean community at the southernmost estuary of the Atlantic coast of Europe

Climate change may enhance the establishment of introduced species, as well as the poleward shift in distribution of numerous species over decades. Long-term research and monitoring of an ecosystem at the southernmost point of the Atlantic coast of Europe should be an important priority in order to detect and understand trends in species composition and the related environmental changes. The Guadalquivir estuary (South West Spain) is more likely to suffer the exacerbated effects of climate change due to its location in the Mediterranean-climate zone. The long-term data set between 1997 and 2006 has allowed us to analyse the variability of the natural and anthropogenic stressors. The mean interannual dissimilarity of the estuarine fauna (Bray–Curtis dissimilarity index) has showed important differences throughout the years, and the species that most contributed to these differences were the exotic species capable of completing their life cycles. This long-term monitoring of the estuarine community has allowed us to anticipate future events and ecological risk assessment in European waters.

Decapod Crustacean Records from A Collection of Marine Soft-Bottom Macrofauna of the Italian Waters Supporting the Update of Checklists and Registers of the Mediterranean Basin

Decapod crustaceans are important components of the fauna of soft-bottom habitats. In this work, the records of decapod crustaceans are provided through the analysis of a large soft-bottom benthic macroinvertebrates dataset of the Central Mediterranean Sea. Decapod crustacean assemblages were collected in the last twenty years by a Van Veen grab in 42 study sites located along the Italian coasts at depths ranging from 1 up to 120 m. The spatial distribution of the crustaceans examined, which include 120 species belonging to 40 families, was investigated according to the biogeographical zones identified in the Italian seas. The spatial distribution of 36 species was updated, comparing the ISPRA decapod crustacean dataset with the most recent Italian checklists. For the species updated, the number of specimens, the year and season of sampling, and environmental data, such as the bathymetric range and habitat details, are provided for each site investigated. Data are discussed and compared with the existing literature, also referring to what is reported in the World Register of Marine Species (WoRMS), with the aim of contributing to the knowledge of the biodiversity of the marine species and supporting the updating of checklists and registers in the Mediterranean Basin.

Mechanical Resistance of the Largest Denticle on the Movable Claw of the Mud Crab.

Decapod crustaceans have tooth-like white denticles that are present only on the pinching side of the claws. In the mud crab, Scylla serrata, a huge denticle exists on the movable finger of the dominant claw. This is mainly used to crush the shells of the crab's staple food. The local mechanical properties, hardness (HIT) and elastic modulus (Er), of the peak and valley areas of the largest denticle were examined via a nanoindentation test. The microstructure and elemental composition were characterized using a scanning electron microscope and energy-dispersive X-ray spectroscopy. The striation patterns originating from a twisted plywood structure parallel to the surface were visible over the entire denticle. Most of the largest denticle was occupied by a hard area without phosphorus, and there was a soft layer corresponding to the endocuticle with phosphorus in the innermost part. The HIT of the denticle valley was about 40% lower than that of the denticle peak, and the thickness of the soft endocuticle of the denticle valley was five times thicker than that of the denticle peak. The HIT-Er map showed that the abrasion resistance of the denticle surface was vastly superior and was in the top class among organisms. The claw denticles were designed with the necessary characteristics in the necessary places, as related to the ecology of the mud crab.

Identifying the genes involved in the egg-carrying ovigerous hair development of the female blue crab Callinectes sapidus: transcriptomic and genomic expression analyses

BackgroundCrustacean female sex hormone (CFSH) controls gradually developing adult female-specific morphological features essential for mating and brood care. Specifically, ovigerous hairs are developed during the prepuberty molt cycle of the blue crab Callinectes sapidus that are essential for carrying the eggs until they finish development. Reduced CFSH transcripts by CFSH-dsRNA injections result in fewer and shorter ovigerous hairs than the control. This study aimed to identify the specific genes responsible for ovigerous hair formation using transcriptomic, genomic and expression analyses of the ovigerous setae at three stages: prepuberty at early (OE) and late premolt (OL), and adult (AO) stages.ResultsThe de novo Trinity assembly on filtered sequence reads produced 96,684 Trinity genes and 124,128 transcripts with an N50 of 1,615 bp. About 27.3% of the assembled Trinity genes are annotated to the public protein sequence databases (i.e., NR, Swiss-Prot, COG, KEGG, and GO databases). The OE vs. OL, OL vs. AO, and OE vs. AO comparisons resulted in 6,547, 7,793, and 7,481 differentially expressed genes, respectively, at a log2-fold difference. Specifically, the genes involved in the Wnt signaling and cell cycle pathways are positively associated with ovigerous hair development. Moreover, the transcripts of ten cuticle protein genes containing chitin-binding domains are most significantly changed by transcriptomic analysis and RT-qPCR assays, which shows a molt-stage specific, down-up-down mode across the OE-OL-AO stages. Furthermore, the expression of the cuticle genes with the chitin-binding domain, Rebers and Riddiford domain (RR)-1 appears at early premolt, followed by RR-2 at late premolt stage. Mapping these 10 cuticle protein sequences to the C. sapidus genome reveals that two scaffolds with a 549.5Kb region and 35 with a 1.19 Mb region harbor 21 RR1 and 20 RR2 cuticle protein genes, respectively. With these findings, a putative mode of CFSH action in decapod crustaceans is proposed.ConclusionsThe present study describes a first step in understanding the mechanism underlying ovigerous hair formation in C. sapidus at the molecular level. Overall, demonstrating the first transcriptome analysis of crustacean ovigerous setae, our results may facilitate future studies into the decapod female reproduction belonging to the suborder Pleocyemata.

Variation in larval traits between closely related species of freshwater prawns (Macrobrachium amazonicum and M. pantanalense)

AbstractLarval morphology is a valuable tool for understanding the life history of decapod crustaceans. This approach has proven valuable in confirming taxonomic revisions based on molecular or adult morphology analyses. Therefore, the present study aimed to compare larval traits (e.g. development time, morphology, and larval size) between Macrobrachium amazonicum and M. pantanalense, two closely related species that are separated by a low genetic distance. The first five zoeal stages of each phenotype and species were analysed. Differences in larval development time, morphology, and size were observed. M. amazonicum exhibits faster development during the early larval stages compared to M. pantanalense. The main morphological difference between the two species is related to the stage at which pereiopod five develops as a functional appendage, namely zoea IV in M. amazonicum and zoea III in M. pantanalense. In addition, size variation was observed, with M. pantanalense larvae being larger in the early stages. The differences found between the two species corroborate that M. amazonicum and M. pantanalense are distinct lineages. Even though these groups are separated by a low genetic distance, the existing differences are conclusive, and therefore, these organisms can be considered as two distinct taxonomic entities.

Diet of the North American river otter (Lontra canadensis) in North Carolina using 2 methods

AbstractRiver otters (Lontra canadensis) are key predators in North Carolina's aquatic systems, but they are often seen as competitors by anglers and fish hatcheries. River otter diets typically consist of fish and crayfish, but also include occasional herpetofauna, mammals, and birds. While standard diet studies focus on identification of prey through manual examination of stomach contents and feces, metabarcoding DNA analysis has become more popular to determine the presence or frequency of species that are often missed, misidentified, or underestimated. We collected river otter carcasses from licensed trappers and fur dealers across North Carolina from the 2009–10 trapping season through the 2015–16 season. We conducted necropsies and analyzed the stomach contents using standard observational methods and metabarcoding DNA analysis. We manually examined 522 river otter stomachs, of which 377 contained prey items. Decapods (crustaceans) were identified in 41% of stomachs and made up similar percentages within each Furbearer Management Unit (FMU). The order Perciformes composed the majority (62%) of fish prey across all stomach samples. Coastal Plain river otters primarily consumed crustaceans (50%) and fish (40%). Piedmont and Mountain river otters consumed fish (32% and 42%, respectively) most often followed by crustaceans (62% and 50%, respectively). Prey selection was similar between the sexes. Out of 368 samples, metabarcoding DNA examination was able to reliably match 164 prey items to species, 5 classes, 18 orders, 25 families, and 42 genera. Fishes made up 33% of the identifications, particularly Perciformes (13%), Cypriniformes (7%), and Siluriformes (5%). Twelve percent of identifications was made up by Amphibia, split evenly by Anura and Urodela. No birds or reptiles were detected in the Mountain or Piedmont FMUs, and no mammals were detected in the Coastal Plain or Mountain FMU. Overall, river otters in North Carolina consume a large variety of prey that varied regionally. The manual examination provided identifications that were not provided by the DNA examination (i.e., crayfish, brown snakes), while the DNA examination provided a more accurate identification of the broad array of prey items. To understand the composition of annual river otter diets we encourage managers to expand research to evaluate river otter diets year‐round and incorporate additional noninvasive methods (e.g., scat surveys) throughout the year.

Freshwater decapod crustaceans from the state of Minas Gerais, Brazil: species composition and distribution.

Brazil contains about 5% (~120 spp.) of the total known species of freshwater decapods. Information on the occurrence of freshwater decapod species in the state of Minas Gerais is dispersed and much of this remains unpublished. We hereby propose to present the first inventory of freshwater decapods from the state, based on data compiled from publications and scientific collections and obtained from fieldwork in the state. Eleven species of freshwater decapods were recorded in Minas Gerais, including three species of crabs (Trichodactylidae), seven of shrimps (Palaemonidae) and one species of freshwater squat lobster (Aeglidae), classified into three infraorders, three families, and four genera. The genus Macrobrachium C.S. Bate, 1868 comprised most of the decapod records. The reduced number of species in relation to coastal states is related, at least in part, to the absence of amphidromic species. Environmental degradation and the construction of dams in several watersheds may be possible causes of this absence. The records obtained from surveys carried out in national parks situated in Minas Gerais and its surroundings indicate the importance of these areas for the conservation of decapod fauna in the state.