Blue Land Crab Research Articles

Using Public Sightings to Document the Widespread Distribution of the Non-Endemic Blue Land Crab, Cardisoma guanhumi, in South Carolina

Using Public Sightings to Document the Widespread Distribution of the Non-Endemic Blue Land Crab, Cardisoma guanhumi, in South Carolina

Occurrence and Health Risk Assessment of Heavy Metals in the Blue Land Crab (Cardisoma guanhumi) from a Tropical Mangrove Swamp.

Coastal ecosystems in the Caribbean are vulnerable to pollution from land-based activities with possible impacts to human health. Ten heavy metals in the blue land crab, Cardisoma guanhumi, harvested from the Caroni Swamp, Trinidad, were investigated in the wet and dry seasons. Metal concentrations (µg g-1 dry weight) in crab tissue were: As (0.15-6.46), Ba (0.69-19.64), Cd (< 0.001-3.36), Cr (0.63-3.64), Cu (26.64-120.31), Hg (0.09-1.83), Ni (1.21-9.33), Se (0.19-1.55), V (0.16-0.69) and Zn (121.06-494.3). There were seasonal differences in the concentration of some heavy metals and, Cu and Zn exceeded the local maximum permissible levels for fish and shellfish at several sites in either one or both seasons. Health risk assessment based on estimated daily intake, target hazard quotient and hazard index revealed that Cardisoma guanhumi harvested from the Caroni Swamp, does not pose a health risk to consumers.

Fipronil use and associated effects on hematological and biochemical parameters of blue land crab (Cardisoma guanhumi Latreille): Ecological implication.

Fipronil is used to control pests to improve farm yield, however, indiscriminate use of fipronil has been reported to endanger crabs leading to their extinction. Therefore, this study investigated the impact of fipronil on several hematological and biochemical parameters of blue land crabs. We exposed blue land crabs to either fipronil or to a control treatment; fipronil reduced the protein content of the crab and also led to hematological and oxidative damages to the crabs' oxy-hemocyanin. Based on our results, there is need for guided use of agrochemicals such as fipronil to avoid/reduce their adverse effects on economically important species such as crabs.

Seasonal variation in biometric parameters in a population of the endangered blue land crab (Cardisoma guanhumi): Indicators for assessment and management

Cardisoma guanhumi is a land decapod crustacean distributed along the eastern Atlantic. Currently, this species is included in the Brazilian list of aquatic species overexploited or threatened with overexploitation. This study performed biometric analysis and assessed reproductive dynamics of the blue land crab Cardisoma guanhumi in Acaú-Goiana Extractive Reserve, a coastal marine protected area in northeast Brazil. From January 2019 to December 2020, biometric data were evaluated from 539 captured individuals by an artisanal trap. In addition, male gonads and hepatopancreas were removed and fixed in formalin solution to analyse morphological reproductive indicators by gonadal (GSI) and hepatosomatic (HSI) index calculation. In summary, the population of blue land crab showed 322 males and 217 females. We observed a difference in variation of mean seasonal carapace width (54.73–56.67 mm). The condition factor ranged from 0.97 to 1.07, showing significant differences between the years and the seasons with high values observed in the dry season in 2019 and 2020. The weight–length relationships showed negative allometric growth for males (b=2.586, a=0.010) and females (b=2.229, a=0.291). The monthly distribution of the hepatosomatic (HSI) index did not show a clear annual pattern, but GSI differed between the months, indicating two seasonal groupings of Jan–Feb and May–August–Nov. The reproductive indicators of C. guanhumi evaluated here may indicate that the environmental influence and fishing pressure are the main factors that drive its reproductive seasons. Thus, it is noteworthy to indicate conservation efforts from January to April, when should be considered the breeding season for the species. In addition, long-term monitoring in the Extractive Reserve Acaú-Goiana must be considered for studies of population structure and gene flow of Cardisoma guanhumi, prioritizing the preservation of their habitats.

Conservation of the endangered blue land crab Cardisoma guanhumi Latreille in Latreille, Le Peletier, Serville &amp; Guérin, 1828 (Decapoda: Brachyura: Gecarcinidae) in Brazil: optimal habitats and environmental factors

Abstract Cardisoma guanhumi Latreille in Latreille, Le Peletier, Serville &amp; Guérin, 1828, the blue land crab, is a marine semi-terrestrial crab that builds burrows in different habitats along estuaries, an ecosystem severely modified and fundamental to this endangered species in Brazil. The presence of adequate habitats and physical, chemical, and biological conditions often determine the spatial distribution of populations. We aimed to characterize the most relevant environmental conditions among the main environments present in southern Bahia state, Brazil, and evaluate their influence on the spatial distributions of C. guanhumi to define which habitats are most critical for the conservation of the species. Our results showed that there is no relationship between spatial distributions and any particular habitat, but instead to the physical and other environmental parameters studied. Low-elevation areas along the river shore, shading, a supply of leaf litter, and bare sandy substrate are highlighted as priority for the conservation of C. guanhumi. These physical factors limit the distribution of juveniles, which form dense groups on river shores without significant differences between habitats. The preservation of the native forest and restinga shrubs that border rivers appear as fundamental for the conservation of the species.

Genetic diversity of the blue land crab Cardisoma guanhumi (Latreille 1825) in the Alvarado Lagoon System in Veracruz, gulf coast of Mexico

In the Alvarado Lagoon System (ALS) in south-central Veracruz on Mexico's gulf coast, the blue land crab, Cardisoma guanhumi, a semi-terrestrial crustacean species, represents an important fishery resource, but one that is subject to overexploitation and habitat destruction. Identifying genetic diversity and the genetic unit are required to establish efficient conservation strategies. The present study's goal was to assess the genetic structure and degree of genetic diversity of C. guanhumi populations along the ALS. A fragment of the D-loop region of the mtDNA (750 bp) and a partial sequence of the COI gene (580 pb) was sequenced for 120 specimens collected at four sites in the ALS. Genetic diversity indices were estimated for each marker. The study sites' gene flow was estimated, as was the effective population size and the mutational rate for each locality. A haplotype network was built to estimate the gene genealogies of the populations. A Tajima's neutrality test, Fu tests, and mismatch analysis were performed to detect demographic expansion. Results show that this C. guanhumi population has high genetic diversity with a large gene flow among the localities studied and expanded during the recent evolutionary past. All haplotypes from both markers are novel for the species, according to the NCBI GenBank. The high genetic diversity and genetic connectivity among sites suggests that the size of blue crab populations in the ALS has not been drastically affected by past exploitation. Finally, management strategies are proposed to protect the species.

MORPHOMETRY OF BLUE LAND CRAB (CARDISOMA GUANHUMI) BURROWS: ICHNOLOGICAL CONTEXT AND PALEOENVIRONMENTAL IMPLICATIONS

ABSTRACT A large brachyuran, the blue land crab (Cardisoma guanhumiLatreille, 1825) is a keystone species and a prolific burrower in a variety of low-latitude supratidal habitats; however, few studies have addressed its ichnological aspects. Here we present a detailed morphological assessment of C. guanhumi burrows and make comparisons to Macanopsis plataniformis, a trace fossil thought to be constructed by a similar brachyuran. Using nine burrow casts from a mangrove wetland on San Salvador Island, Bahamas, 29 dimensionless morphometric parameters were compared. Results of Bray-Curtis tests show high overall similarity index (0.85) between casts, with complexity, tortuosity, and opening inclination angle having moderate to high similarity (&amp;gt; 0.8). End chamber angle of the blue land crab has highest similarity both within the modern morphometric parameter dataset (&amp;gt; 0.9) and to that of M. plataniformis (0.88). The large terminal chamber is particularly important because of its high preservation potential, as a repository for organic remains, and as a reliable water table (∼ sea-level) indicator. Cluster analysis suggests size-independent Macanopsis-resembling burrow morphology among different extant taxa can be discriminated via quantitative neoichnological methods. Our findings demonstrate how a quantitative assessment of modern burrows and their likely counterparts from the sedimentary record can help constrain tracemaker identity and aid paleoenvironmental reconstruction of low-energy microtidal settings.

Observing the Impact of Confinement on the Rearing of Land Crabs

The study observed the impact of confinement on the rearing of land crabs in an attempt to produce crabs that can be consumed without having to worry about their unwholesomeness, traceability and also the possibility of producing crabs all year round.Two species of the land crabs were observed for five months: 35 Rainbow land crabs, obtained from Ada, a suburb of the Greater Accra Region of Ghana and 20 Blue land crabs obtained from Sokode, a suburb of the Volta Region of Ghana. the study investigated the 55 land crabs by observing their coexistence, feeding and reproduction in confinement. Dealers in land crabs and other resource persons who had some experience with land crabs where interviewed. At the beginning of the study, the average weight of a male rainbow land crab was 3.3 pounds and that of a female was 3.0 pounds. However, at the end of the study the average weight recorded for the male Rainbow land crab was 5.7poundsand that of the female was 5.4pounds. The number of rainbow land crabs that died during the cause of the study was 7 and 12 escaped resulting in 16 of them remaining by the end of the study. Six of the crabs lost their appendages, one female moulted, 4 female crabs produced eggs and spawned. The only female Blue land crab that survived produced eggs in confinement but later died after three weeks from the commencement of the study. Results of the study showed that the Rainbow land crabs are hardier as compared to the Blue land crabs and thus, the best specie that can be reared in confinement. The Rainbow land crabs can be reared in confinement for a minimum period of five months if the confined area is darkened and hideout accessories provided. The crabs can be fed on a range of diets, from fish, vegetables to leftovers from the kitchen. However, the crabs seem to prefer sugar cane, palm fronds and fruits. The female Rainbow land crabs are capable of spawning in confinement when provided with the right conditions and environment.

Parámetros de crecimiento de Cardisoma guanhumi en el departamento del Magdalena, Colombia

In Colombia, the blue land crab Cardisoma guanhumi faces two main threats: extraction and habitat loss. This project aims to show an approximation of the growth parameters of C. guanhumi in protected areas within the Magdalena department. Individuals were captured monthly from May to October 2016 in five localities in the Tayrona National Natural Park (PNNT) and the Salamanca Island Road Park (VIPIS). A total of 816 crabs were collected, each of which was measured, weighed, sexed and released. Both sexes showed a negative allometric length-to-weight ratio. Using the FiSAT II program's ELEFAN I routine, the size frequencies obtained were analyzed in order to determine the growth parameters for 1) the department, considering gender, and 2) the PNNT, where the data from VIPIS wasexcluded. The asymptotic carapace width was higher for males (109.16 mm) than for females (96.74 mm), but the growth coefficient (K) was higher for females (0.19 year-1) than for males (0.15 year-1). Growth performance indexes were similar: 3.252 for males and 3.250 for females. The FISAT II length converted catch curve routine was used to calculate the total (Z), natural (M), and fishing (F) mortalityrates, as 0.41, 0.36, and 0.05 year-1 respectively. The grow coefficient K was higher for the PNNT (0.29 year-1) than for the Magdalena department (0.15 year-1), thus, longevity was lower for the PNNT (tmax= 10.42 years) compared to the department (tmax= 20.06 years). Ingeneral terms, the C. guanhumi population in the study area is longevous, slow growing, with low extraction morality. The data obtained in this work are important in the management of this species, as its slow growth makes it vulnerable to overfishing.

&lt;b&gt;Traditional knowledge and variations in capture techniques used for blue land crab (&lt;i&gt;Cardisoma guanhumi&lt;/i&gt;, L. 1825) along the coast of Paraíba, Brazil

The Mamanguape estuary, located in the Paraiba State (Brazil), hosts many traditional fishing communities and Amerindian villages whose use of the regional natural resources is fundamental to their cultural and physical survival. The aim was to register the traditional local knowledge about the different fish techniques, the influence of the dynamics of the natural environment on the activities of the blue land crab, and the relationships between the sizes of their dens and the sizes of the animals themselves. The only technique used to capture blue land crab is a trap called ‘mousetrap’. It was recorded different materials such as PET bottles, to build the traps. The fishermen stated that fruits are used as bait as well as sugar-cane and onions. The phases of the moon and the different tides do not significantly influence their activities as the crabs inhabit higher lands beyond the influence of normal tides. The knowledge documented here concerning the blue land crab demonstrated that these shell fish harvesters have a detailed understanding of their environment based on observations and empiricism that allows them to determine which techniques and strategies will increase their chances of capturing their prey and consequently guaranteeing their income.

Site fidelity and population structure of blue land crabs (Cardisoma guanhumi Latreille, 1825) in a restricted-access mangrove area, analyzed using PIT tags

Understanding the patterns of displacement and site fidelity in blue land crabs (Cardisoma guanhumi Latreille, 1825) has important implications for their conservation and management. The central objective of this study was to analyze seasonal variations in site fidelity in C. guanhumi, a species that is intensively exploited in Brazil, in spite of being part of the Official National List of Critically Endangered Species. This species currently suffers multiple severe threats, such as overharvesting and habitat destruction. C. guanhumi were sampled monthly at four fixed sectors that were delimited at the upper fringe of a restricted-access mangrove at Itamaracá Island between April 2015 and March 2016. One thousand and seventy-eight individuals were captured, measured, sexed, weighed, and their color patterns registered. Of these, 291 individuals were tagged with PIT (Passive Integrated Transponder) tags. Ninety-seven individuals (size range 27.0–62.6 mm carapace width) were successfully recaptured, totaling 135 recapture events. The largest interval between marking and recapture was 331 days. Through the use of mark-recapture-based models, it was possible to estimate the local population as being 1312 (± 417) individuals (mean density 2.23 ± 0.71 ind. m−2). Considering the mean density of burrow openings and individuals, there were 3.4 burrow openings per individual. C. guanhumi showed a clear philopatric behavior. Seventy-seven percent of recaptured individuals were recaptured in their sector of origin, and the remainder in an adjacent sector. Site fidelity was higher in females. Males showed minimum site fidelity in October, which is most likely related to be the onset of the reproductive season. The present study opens new perspectives for the definition of reproductive seasons, based on seasonal changes in behavior, and thus to improve the conservation of exploited and severely threatened species.

Ecohydrological controls on blue crab landings and minimum freshwater inflow to the Caloosahatchee Estuary, Florida

Quantitative relationships between biological resources and hydrological variables are often needed to fulfill legislative requirements for management of estuaries and coastal waters. We used a 28-year record of blue crab landings to support development of a minimum flow (defined in Florida Statutes as the point at which further withdrawals of freshwater will cause “significant harm” to the resources or ecology) for the Caloosahatchee Estuary in Florida, USA. Annual catch per unit effort (CPUE) was computed from monthly landings of crabs and measures of fishing effort. Both unadjusted and de-trended annual CPUE were significantly correlated with rainfall, freshwater inflow and the Multivariate ENSO Index during the previous year’s dry season. Increases in CPUE from 1 year to the next were positively related to dry season rainfall in the first of the 2 years. The Minimum Flow was intended to protect the resources from an impact taking 2 or more years to recover. Geometric mean functional regressions and Monte Carlo simulations were used to identify the dry season rainfall associated with this level of impact. Both a spectral analysis and the Monte Carlo simulations indicated that this level of rainfall occurred about once every 6 years. The corresponding Minimum Flow ranged from 8.6 to 12.3 m3/s (averaged over the dry season and measured at the headwater control structure of the estuary). This study demonstrated the relationship between hydrologic variables (rainfall, freshwater inflow) and blue crab landings and the usefulness of fisheries catch data in providing the technical basis for developing environmental flow targets.

Estimation of density and abundance of the blue land crab, Cardisoma guanhumi Latreille, 1828, in the Imburana peninsula, northern Brazil

The blue land crab (Cardisoma guanhumi Latreille, 1828) supports extensive small-scale artisanal fisheries in the tropical western Atlantic, including Brazil. Land surveys were conducted on a peninsula in a northeastern Brazilian estuary in 2014-2015 in order to evaluate density and abundance. The study area (26 700 m2) was dividied into three subareas with a total of 30 sampling points. In all, 529 burrows were registered of which 71.7% were open (indicating activity), 22.1% were closed (indicating moulting) and 6.2% were empty (fishermen catch). Burrow diameter ranged from 12 to 174 mm (mean: 62.05 ± 3.01 mm; 95% confidence interval). The highly significant correlation between mean burrow diameter and mean carapace length (n = 7; R2 = 0.8968, ) shows that one is a good proxy for the other. The estimated total population size in the study area was 10 362 individuals, with a mean density of 0.39 individuals/m2 (stock of 7347 kg).

Caracterização Topográfica do Habitat do Cardisoma guanhumi Latreille, 1828 (Decapoda, Gecarcinidae) na Apa Costa dos Corais (Pernambuco e Alagoas, Brasil)

In the period from July to September 2012, a survey was made of the number of burrows of blue land crab ( Cardisoma guanhumi ), both in twelve profiles distributed in areas of mangrove, positioned perpendicularly to the wetlands of the Una's River (Pernambuco) and Camaragibe's River (Alagoas), aiming to acquire information on the distribution of holes in different types of topographies. The depth of burrows and the salinity and temperature of the water at the bottom of the burrows was registered. In Pernambuco and Alagoas, the profiles covered steep areas (with a gradient of 4.5°) and shallow areas (with a gradient of 0.02°). The maximum distance between existing burrows in the profiles, ranged from 58m and 359.5m, compared to a benchmark level (RN). The burrows depths ranged from 0.45m to 1.90m, with an depth average of 0.99m (DP = 0,29). The maximum depth of the burrows can be justified by the fact that there is less availability of water in northeastern soils.It is recommended, studied the mangroves, the establishment of an exclusion zone to preserve the habitat of Cardisoma guanhumi , a distance of at least 200m above the high tide mark. Keywords: blue land crab; mangrove; burrows.

Shellfish as reservoirs of bacterial pathogens

Shellfish comprises a variety of animals including bivalves – oysters, clams, quahogs, scallops, mussels, and others including crustaceans – lobsters, crabs, and shrimps. Shellfish naturally found in Grenada, an island nation in the Caribbean, include: blue land crabs (Cardisoma guanhumi), clams (Mercenaria mercenaria), oysters (Isognomon isognomon), queen conchs, also called “lambi” (Strombus gigas), and whelks (West Indian top shell) (Cittarium pica), all of which are used for human consumption in this country. Bacteria are ubiquitous in the marine environment. Shellfish can be a source of commensal bacteria that can be pathogenic to shellfish, as well as those pathogenic to humans. Raw and partially cooked molluscan shellfish (clams, oysters, and mussels) have a long history as vectors of infectious agents[1]. According to Potasman et al.[2], the earliest reports of shellfish-transmitted diseases were documented in the late 19th and early 20th century. Apart from typhoid fever, the most notable examples include Vibrio species, which account for 20% of all outbreaks of shellfishassociated human disease. Other bacteria are Salmonella species, Shigella species, Plesiomonas shigelloides, and Listeria species[2]. Several Vibrio species native to both marine and estuarine environments, have been identified as the causative agents of shellfish-associated human illnesses. These include Vibrio parahaemolyticus (V. parahaemolyticus), Vibrio vulnificus (V. vulnificus), Vibrio cholerae non-O1, Vibrio cholerae, Vibrio cholerae O1, Vibrio fluvialis (V. fluvialis), Vibrio hollisae, Vibrio mimicus, Vibrio alginolyticus (V. alginolyticus), and unidentified or miscellaneous Vibrio species. Among these, all except V. vulnificus, are associated with gastroenteritis of varying severity[1]. Oysterassociated V. vulnificus septicemia and death were first reported in 1975[3]. Another bacterium of public health concern is Salmonella. Compared to vibrios, there have been much less studies on Salmonella in various shellfish. Setti et al.[4] studied the dynamics of Salmonella contamination in the coastal areas of Agadir, a populous region of Southern Morocco where shellfish production is important to the local economy. Salmonella enterica (S. enterica) serovar Kentucky was found almost exclusively in mussels, whereas Salmonella blockley was found in mussels and sediment samples. Identification of Salmonella to serovar level is required ARTICLE INFO ABSTRACT

Fine-scale genetic structuring, divergent selection, and conservation prospects for the overexploited crab (Cardisoma guanhumi) in tropical mangroves from North-eastern Brazil

Popularly known as blue land crab,Cardisoma guanhumiis heavily exploited as food and considered as an important economic resource in Brazil. In recent decades, the species has experienced a sharp population decline by the loss and/or degradation of its natural habitat and overfishing. The present study aimed to investigate the genetic variation and connectivity among 154 specimens ofC. guanhumisampled along the coast of Pernambuco in five different levels of tropical mangroves conservation. Nine ISSR primers were used for assessing the genetic variation of the species. The genetic diversity observed inC. guanhumiwas high reinforcing the condition of a resilient species, indicating a good conservation status of this resource in Pernambuco. The hypothesis of panmixia was rejected in favour of a heterogeneous distribution of the genotypes ofC. guanhumi(ФST= 0.19) despite the high gene flow observed in the study region. Such difference could be attributed to the candidate loci being under positive selection and differentially distributed between the geographic regions assessed. The genetic structure showed a pattern of fine-scale genetic structuring better fitted to a model of selection-mediated geographic cline. Cluster analysis and candidate loci under positive selection suggested that the populations ofC. guanhumiin the North-central and South coasts of Pernambuco might be different management units and must be managed independently. In conclusion, exhaustion of natural stocks upon which fishing is totally dependent will lead to serious ecological and sociocultural impacts.

Mitochondrial DNA Variation Reveals a Sharp Genetic Break within the Distribution of the Blue Land Crab Cardisoma guanhumi in the Western Central Atlantic.

The blue land crab Cardisoma guanhumi is widely distributed throughout tropical and subtropical estuarine regions in the Western Central Atlantic (WCA). Patterns of population genetic structure and historical demographics of the species were assessed by mtDNA control region sequence analysis to examine the connectivity among five populations (n = 97) within the region for future conservation strategies and decision-making of fishery management. A total of 234 polymorphic nucleotides were revealed within the sequence region, which have defined 93 distinct haplotypes. No dominant mtDNA haplotypes were found but instead a distribution of a few low-frequency recurrent haplotypes with a large number of singletons. A NJ-tree and a median-joining haplotype network revealed two distinct clusters, corresponding to individuals from estuaries located along the Caribbean Sea and Brazilian waters, respectively. AMOVA and FST statistics supported the hypothesis that two main geographic regions exists. Phylogeographical discontinuity was further demonstrated by the Bayesian assignment analysis and a significant pattern of isolation-by-distance. Additionally, tests of neutral evolution and analysis of mismatch distribution indicate a complex demographic history in the WCA, which corresponds to bottleneck and subsequent population growth. Overall, a sharp genetic break between Caribbean and Brazilian populations raised concerns over the conservation status of the blue land crab.

Using Flow-Ecology Relationships to Evaluate Ecosystem Service Trade-Offs and Complementarities in the Nation's Largest River Swamp.

Large river systems are inextricably linked with social systems; consequently, management decisions must be made within a given ecological, social, and political framework that often defies objective, technical resolution. Understanding flow-ecology relationships in rivers is necessary to assess potential impacts of management decisions, but translating complex flow-ecology relationships into stakeholder-relevant information remains a struggle. The concept of ecosystem services provides a bridge between flow-ecology relationships and stakeholder-relevant data. Flow-ecology relationships were used to explore complementary and trade-off relationships among 12 ecosystem services and related variables in the Atchafalaya River Basin, Louisiana. Results from Indicators of Hydrologic Alteration were reduced to four management-relevant hydrologic variables using principal components analysis. Multiple regression was used to determine flow-ecology relationships and Pearson correlation coefficients, along with regression results, were used to determine complementary and trade-off relationships among ecosystem services and related variables that were induced by flow. Seven ecosystem service variables had significant flow-ecology relationships for at least one hydrologic variable (R (2)=0.19-0.64). River transportation and blue crab (Callinectes sapidus) landings exhibited a complementary relationship mediated by flow; whereas transportation and crawfish landings, crawfish landings and crappie (Pomoxis spp.) abundance, and blue crab landings and blue catfish (Ictalurus furcatus) abundance exhibited trade-off relationships. Other trade-off and complementary relationships among ecosystem services and related variables, however, were not related to flow. These results give insight into potential conflicts among stakeholders, can reduce the dimensions of management decisions, and provide initial hypotheses for experimental flow modifications.

Prevalence and Antibiotic Susceptibility of Gram-negative Aerobic Bacteria Cultured from the Intestine and Hepatopancreas of Blue Land Crab (Cardisoma guanhumi) in Grenada, West Indies

Aim: To evaluate the prevalence of aerobic bacteria associated with the intestine and hepatopancreas of blue land crab and the susceptibility of the bacteria to a panel of antimicrobials that included some drugs used for the treatment of bacterial infections in the human and veterinary clinics in Grenada. Study Design: The tested crabs were collected during a three month period from November 2011 to February 2012 from six parishes of Grenada and analyzed in the bacteriology lab in the

Population biology and color patterns of the blue land crab, Cardisoma guanhumi (Latreille 1828) (Crustacea: Gecarcinidae) in the Northeastern Brazil.

The objective of this study was to analyze the population biology and color patterns of Cardisoma guanhumi Latreille, 1828 in a mangrove area in Natal, Rio Grande do Norte, Brazil. Crabs were collected monthly between February 2010 and January 2012 and totaled 1,837 individuals. Sex ratios were similar between males and females in the first year and differed in the second. Sex ratios by size class differed statistically in the extremes of the distribution, with an abundance of males in the large size classes. There was no difference (p > 0.05) in carapace width between males and females in the first year, but in the second year, males were larger than females (p = 0.003), showing the importance of considering interannual variation in such studies. Both sexes presented a unimodal distribution. The size of first maturing of the females was 6.00 cm. Asymptotic carapace width for males was 9.4 cm and females for 9.2 cm, using the Wetherall method. There was no defined modal progression, which made the determination of the Von Bertalanffy growth parameter K impossible. Juveniles were found throughout all months of the year, demonstrating that there was no defined period of recruiting, although slightly fewer juveniles were found in the dry season. Four color patterns were observed, the three first patterns were the same for both sexes, while the fourth pattern was observed in females only. The four color patterns identified could be clearly related to the stage of development (size) and sexual maturity of the animal.