Morphometric comparison between hatchery-reared and wild-caught megalopae of the mangrove crab

The objective of this work was to compare the morphometry of hatchery-reared and wild-caught mangrove crab (Ucides cordatus) megalopae. Ten U. cordatus megalopae of each group (hatchery-reared and wild-caught) were individually analyzed using a stereoscopic microscope equipped with an ocular micrometer. Length, width, and height of all megalopae were measured, and the size of body appendices was determined. The results indicate that the hatchery-reared megalopae are more robust than the wild ones. Furthermore, some significant differences in the size of certain appendices can be cues of the kind of alterations that hatchery-reared individuals experience.

Mangrove sedimentary characteristics and implications for crab Ucides cordatus (Crustacea, Decapoda, Ucididae) distribution in an estuarine area of the Amazonian region

At the coastal zone sediments, water and organisms interact intensely. At equatorial tidal-dominated coast mangroves are abundant. These areas are well-known for their ecological importance. Considering the mangroves of Atlantic South America, the mangrove crab, Ucides cordatus has ecological and economic prominence. High densities of this crab are found on the Amazon coast. This study investigates the sediment distribution of the Bragança mangrove area (Amazon coast, Brazil) and its correlations with vegetation and mangrove crab distribution. Sediments of 47 sites, as well as crabs from sites with different sediment and vegetation, were sampled. Results show that surface sediment of the area is mainly composed by silt (59%), with 21% sand and 20% clay. Variations in sorting and skewness are the product of local variations in clay and sand content. The vegetation type was significantly correlated to mangrove crab characteristics, abundance and weight/size. Sediment characteristics are also substantially different according to the vegetation type. Areas where Avicennia germinans prevails have more sand and clay than areas of Rizophora mangle, in which silt is dominant and crabs were significantly heavier. The present results have showed that the distribution of sediments, crabs and vegetation at mangrove areas are strongly correlated. Thus, they should be studied in conjunction.

Bioecology of the crab Ucides cordatus (Crustacea, Decapoda) in mangroves influenced by the Amazon River, Brazil

The mangrove crab (Ucides cordatus) is a valuable fishery resource, overfished along the Brazilian coast. This study aimed to obtain bioecological data on this crab along the coast of the State of Amapá. Six bimonthly samplings were conducted between December 2008 and January 2010. Transects were used to estimate the density (burrows m-2) and population abundance (individuals m-2). All the animals were subjected to biometrics, with females being classified according to their stage of gonadal maturation. The mean density (1.09 burrows m-2) and abundance (0.31 individuals m-2) were influenced by the climate with the highest values in summer (1.17 burrows m-2 and 0.34 individuals m-2). The male to female ratio was 1.38:1 showing significant difference in the proportion of sexes. The individuals showed sexual dimorphism, with linear measurements significantly higher in males. The sampled animals also had larger carapace length and width (CL and CW) compared to crabs studied in other Brazilian states. There was a positive relationship between CW and CL and individual weight (IW) and CW for males (R² = 0.83 and 0.90) and females (R² = 0.79 and 0.84). The growth was negative allometric (CL increases to a lesser extent than CW) for both sexes. The highest frequency of ovigerous females (78%) and in maturation stage IV (38%) occurred in the CW size class between 59.8 and 67.5 mm. The peak of mature females occurred in May and August, showing a reproductive period different from those in other Brazilian states.

Cytochemical characterization of gill and hepatopancreatic cells of the crab Ucides cordatus (Crustacea, Brachyura) validated by cell metal transport

Ucides cordatus (Linnaeus, 1763) is a hypo-hyper-regulating mangrove crab possessing gills for respiratory and osmoregulatory processes, separated in anterior and posterior sections. They also have hepatopancreas, which is responsible for digestion and absorption of nutrients and detoxification of toxic metals. Each of these organs has specific cells that are important for in vitro studies in cell biology, ion and toxic metals transport. In order to study and characterize cells from gills and hepatopancreas, both were separated using a Sucrose Gradient (SG) from 10 to 40% and cells in each gradient were characterized using the vital mitochondrial dye DASPEI (2-(4-dimethylaminostyryl)-N- ethylpyridinium iodide) and Trichrome Mallory's stain. Both in 20 and 40% SG for gill cells and 30% SG for hepatopancreatic cells, a greater number of cells were colored with DASPEI, indicating a larger number of mitochondria in these cells. It is concluded that the gill cells present in 20% and 40% SG are Thin cells, responsible for respiratory processes and Ionocytes responsible for ion transport, respectively. For hepatopancreatic cells, the 30% SG is composed of Fibrillar cells that possess larger number of membrane ion and nutrient transporters. Moreover, the transport of toxic metal cadmium (Cd) by isolated hepatopancreatic cells was performed as a way of following cell physiological integrity after cell separation and to study differences in transport among the cells. All hepatopancreatic cells were able to transport Cd. These findings are the first step for further work on isolated cells of these important exchange epithelia of crabs, using a simple separation method and to further develop successful in vitro cell culture in crabs.

Lethargic crab disease: multidisciplinary evidence supports a mycotic etiology

Although lethargic crab disease (LCD) is causing massive mortalities in populations of the mangrove crab Ucides cordatus of Northeastern Brazil, the identity of its etiological agent was hitherto unknown. In this study we provide robust evidence suggesting that LCD is caused by an anamorph Ascomycota (Fungi). We examined specimens of U. cordatus collected from stocks affected by LCD. Histological and TEM methods detected the presence of hyphae, conidia, and condiophores in several host tissues. Moreover, the abundance of fungal stages is negatively associated with crab health. Finally, DNA was isolated from the fungus and a region of its 18S ribosomal gene was sequenced. Phylogenetic analyses not only confirm the diagnosis of the LCD fungus in crab tissues as an ascomycete, but also suggest a close relationship with members of the subphylum Pezizomycotina.

Different pathways in the larval development of the crab Ucides cordatus (Decapoda, Ocypodidae) and their relation with high mortality rates by the end of massive larvicultures

One of the most limiting factors affecting the larval rearing of Ucides cordatus in the laboratory is a period of high mortality, which usually occurs late in the course of the larviculture during the metamorphosis from the zoeal to the megalopal phase. The objective of the present research was to analyze the post-embryonic development of U. cordatus on an individual basis and, in particular, to search for patterns linking disturbances in the molting process to the high larval death rates observed in massive larvicultures. A total of 50 larvae were individually reared from hatching to metamorphosis into the megalopal phase under controlled conditions, fed a combination of microalgae and rotifers. The survivorship rate was 70% until zoea V. The 35 surviving zoea V larvae followed two different pathways. Eleven underwent metamorphosis directly to megalopa, eighteen molted to zoea VI and six died as zoea V. In the last molting event, only two zoea VI larvae reached the megalopal stage, while the remaining sixteen died. In further observation under microscope, 13 of the dead zoea VI showed characteristics of the pre-molt stage and pereiopods disproportionably large in relation to the carapace. The observed pattern resembles the Molt Death Syndrome (MDS) described for other decapod species, in which larvae die in the late pre-molt phase of the molting cycle. We suggest that U. cordatus larvae develop disturbances in the molting process similar to the MDS described for other species and that these disturbances are related to a more complex pathway involving the emergence of larval stage zoea VI.

Gonad development in females of fiddler crab Uca rapax (Crustacea, Brachyura, Ocypodidae) using macro and microscopic techniques

The morphology of the ovaries in Uca rapax (Smith, 1870) was described based on macroscopic and microscopic analysis. Females were collected in Itamambuca mangrove, Ubatuba, state of São Paulo, Brazil. In the laboratory, 18 females had their ovaries removed and prepared for histology. Each gonad developmental stage was previously determined based on external and macroscopic morphology and afterwards each stage was microscopically described. The ovaries of U. rapax showed a pronounced macroscopic differentiation in size and coloration with the maturation of the gonad, with six ovarian developmental stages: immature, rudimentary, developing, developed, advanced and spent. During the vitellogenesis, the amount of oocytes in secondary stage increases in the ovary, resulting in a change in coloration of the gonad. Oogonias, primary oocytes, secondary oocytes and follicular cells were histologically described and measured. In female’s ovaries of U. rapax the modifications observed in the oocytes during the process of gonad maturation are similar to descriptions of gonads of other females of brachyuran crustaceans. The similarities are specially found in the morphological changes in the reproductive cells, and also in the presence and arrange of follicle cells during the process of ovary maturation. When external morphological characteristics of the gonads were compared to histological descriptions, it was possible to observe modifications that characterize the process in different developmental stages throughout the ovarian cycle and, consequently, the macroscopic classification of gonad stages agree with the modifications of the reproductive cells.

Population biology of the crab Armases angustipes (Crustacea, Decapoda, Sesarmidae) at Brazilian tropical coast

The semi terrestrial crabs are important elements of the fauna of coastal regions. The aim of this study was to analyze the population structure of Armases angustipes (Dana, 1852) at estuaries of the Ariquindá River, considered a non impacted area, and Mamucabas River, considered a few impacted area, on the south coast of state of Pernambuco, Brazil. The species occurred in all months of the year. The number of individuals per month varied, being higher in the months of transition between the seasons. This is probably due to significant seasonal variations of air and burrow temperature and burrow salinity. There was no sexual dimorphism in size of A. angustipes in the mangrove of Ariquindá River, but males were larger than females in the mangrove of Mamucabas River. In both estuaries, the sex ratio did not differ from Mendelian proportion, but showed a deviation for females. The analysis of temporal variation in sex ratio showed significant differences in some months of the year. These variations are due to cyclical events that act distinctly on each sex. In both estuaries, size classes of carapace width were equally represented by both sexes. The ovigerous females of A. angustipes occurred only in some months of the year, especially in summer, in both estuaries. Probably the high phytoplankton productivity observed in summer favors the reproductive activity, since these algae serve as food for the larvae. Specimens of the population of Rio Ariquindá are largest and wider than those of Mamucabas River. This fact, associated with the low abundance of crabs and the lower frequency of ovigerous females observed in Mamucabas River, is an indication that this population may be influenced by the environmental impacts that this estuary has received.

Morphometry of testis and seminiferous tubules of the adult crab-eating fox (Cerdocyon thous, Linnaeus, 1766)

Body and testicular biometric parameters are very important for establishing reproductive patterns and, consequently, the development of protocols for assisted reproduction in different species. A direct correlation between the testis weight and the sperm population was observed in other studied species, because the testis size primarily reflects the total volume of the seminiferous tubule, its main component. The objective of this study was to determine the testicular volume parameters and correlate data from morphometry of testis and seminiferous tubules with body mass in six adult crab-eating foxes. The mean body weight of the crab-eating foxes in this study was 6.53 kg, with approximately 0.068% allocated to the testicular mass and 0.042% specifically to seminiferous tubules, which represented 87.5% of the testicular parenchyma. The albuginea comprised 12.5% of the testicular mass. The mean diameter of seminiferous tubules was 236 µm, and the mean thickness of the seminiferous epithelium was 62.9 µm. Values of tubular parameters indicate a sperm productivity close to those observed in previously studied carnivores.

MANGROVE BARK: A RENEWABLE RESIN SOURCE FOR WOOD ADHESIVES

From four solutions tested to extract tannins from mangrove bark for wood adhesives, hot water is recommended. Hot water extracted 21.4% of formaldehyde-hydrochloric acid reactive polyphenols on oven-dry bark basis.

Mangrove vegetation in Amazonia: a review of studies from the coast of Pará and Maranhão States, north Brazil

The present study is a compilation of the literature about vegetation of mangrove forest of the north coast of Brazil. It synthesizes the knowledge about this important ecosystem and lists the currently available literature. The study focuses on the coast of Pará and Maranhão states, which are covered by a continuous belt of mangroves. The mangrove flora comprises six mangrove tree species and several associated species. Mangrove tree height and stem diameter vary as a function of abiotic local stand parameters. Seasonal variation in rainfall and salinity affect the species' phenology and litter fall. Local population use products derived from mangrove plants for different purposes (e.g. fuel; medicinal; rural construction). The increase in the coastal population has given rise to conflicts, which impact on mangrove forest.

Relative growth of Uca burgersi (Crustacea, Ocypodidae) from two mangroves in the southeastern Brazilian coast

The relative growth of the fiddler crab Uca burgersi Holthuis, 1967 was analyzed in two populations from different mangroves (Ubatumirim and Cavalo rivers) in the southeastern Brazilian coast, monthly sampled from May, 2001 to April, 2002. The population from a high productivity level mangrove reaches the sexual maturity in larger sizes than the population from a less productive site. This results can be attributed to the greater amount of nutrients found in the Cavalo than in Ubatumirim mangrove.

The interference of methods in the collection of teredinids (Mollusca, Bivalvia) in mangrove habitats

In the estuary of the Mamanguape River (Paraíba, Brazil), a new collection technique was developed and applied with virgin poles of mangrove trees Avicennia schaueriana (Verbenaceae), Rhizophora mangle (Rhizophoraceae), and Laguncularia racemosa (Combretaceae), taking into account wood preference, water salinity and depth influence during teredinid larval settlement. Sets of poles were vertically fixed in the riverbed at three sites along a decreasing salinity gradient, where they stayed for four months. The poles were collected and divided into upper, median, and lower segments, in agreement with different immersion regimes. An increase of 239% was obtained in the number of individuals when compared to a previous study in the same area using a different methodology. The species Teredo bartschi (Clapp, 1923), Nausitora fusticula (Jeffreys, 1860) and Bankia fimbriatula Moll & Roch, 1931 were registered in both studies, and the species Psiloteredo healdi (Bartsch, 1931) is here registered for the first time as occurring in that estuary. The species Neoteredo reynei (Bartsch, 1920), previously registered on tree branches of the mangrove habitat, was not found in the present work. Bankia fimbriatula, the most abundant species, did not show preference for any substratum but occurred significantly on the lower segment of the poles. N. fusticula, second in abundance, preferred to settle on poles of A. schaueriana and on any of the three segments. Aiming to assess the habitat variations, a more accurate study on teredinids diversity in mangrove ecosystems should be performed through a concomitant analysis from tree branches of the mangrove habitat, as well as from poles of mangrove trees or panels made of pine wood or mangrove trees wood. These collection devices should be maintained along a decreasing salinity gradient exposed to different tide levels.

Reproductive biology of the sesarmid crab Armases rubripes (Decapoda, Brachyura) from an estuarine area of the Sahy River, Sepetiba Bay, Rio de Janeiro, Brazil

The aim of this work was to gain knowledge about reproductive biology of the crab Armases rubripes (Rathbun, 1897) from an estuarine area of the Sepetiba Bay. Samples were taken monthly from February 2003 to January 2004 in the Sahy River estuary (22º56'S; 44º01'W), Rio de Janeiro, Brazil. The crabs were collected by hand during 15-minute catch-effort sessions conducted by two people. In the laboratory, the specimens were separated by sex, carapace width was measured and gonadal stage was checked macroscopically. A total of 830 individuals were caught - 304 males, 373 females (60 ovigerous females) and 153 juveniles. The ovigerous females were found almost year-round, except in November and April, showing a continuous reproductive period. They presented a size range from 8.2 to 15.0 mm carapace width (12.1 ± 1.7 mm). Color and macroscopical aspects determined five gonadal stages for males and females (immature, rudimentary, intermediary, developed and resting). First sexual maturity was estimated at 6.5 mm of carapace width for males and 8.1 mm for females. Individual fecundity varied from 200 to 11,460 eggs (4,458 ± 2,739 eggs). Mean egg size was 0.248 ± 0.026 mm, varying from 0.213 to 0.333 mm, while the volume ranged from 0.0051 to 0.0188 mm³ (0.0082 ± 0.0029 mm³).

Shell utilization pattern of the hermit crab Clibanarius vittatus (Crustacea, Anomura) in an estuary at São Vicente, State of São Paulo, Brazil

We evaluated the gastropod shell utilization pattern of the hermit crab Clibanarius vittatus (Bosc, 1802) at Pescadores Beach in São Vicente, State of São Paulo, Brazil. Specimens were collected monthly from May 2001 through April 2003, in the intertidal zone at low tide. The crabs were weighed and their carapace shield length measured. All gastropod shells were identified and had their shell biometric parameters (total length and aperture length) measured (mm) and weighed (g). A total of 2,344 hermit crabs (644 males, 1,594 females, 45 ovigerous females and 61 individuals in intersex), using 13 species of gastropod shells, were collected. Stramonita haemastoma (Linnaeus, 1767), Cymatium parthenopeum (Von Salis, 1793) and Achatina fulica (Bowdich, 1822) comprised over 98% of all the shells. Male and intersex crabs were significantly larger than the females. This size difference strongly influenced the shell utilization pattern, principally in A. fulica, which has the largest shell size, that was only used by males and intersexual individuals of C. vittatus. Cymatium parthenopeum was the only shell species that showed a high determinant coefficient in all the biometric correlations evaluated. The high abundance of S. haemastoma shells and a strong correlation between crab size and shell aperture length established by a significant determination coefficient, indicated that C. vittatus uses this species as the principal resource for shell occupation at Pescadores Beach.