Prevalence of microplastics in Peruvian mangrove sediments and edible mangrove species.

Mangrove ecosystems have been hypothesised as a potential sink of microplastic debris, which could pose a threat to mangrove biota and ecological function. In this field-study we establish the prevalence of microplastics in sediments and commercially-exploited Anadara tuberculosa (black ark) and Ucides occidentalis (mangrove crab) from five different zones in the mangrove ecosystem of Tumbes, Peru. Microplastic were evident in all samples, with an average of 726 ± 396 microplastics/kg for the sediment, although no differences between the different zones of the mangrove ecosystem were observed. Microplastic concentrations were 1.6± 1.1 items/g for the black ark and 1.9 ± 0.9 microplastics/g for the mangrove crab, with a difference in the microplastic abundance between species (p < 0.05), and between the gills and stomachs of the crab (p < 0.01). Human intake of microplastics from these species, for the population in Tumbes, is estimated at 431 items per capita per year. The outcomes of this work highlight that the mangrove ecosystem is widely contaminated with microplastics, presenting a concern for the marine food web and food security.

Cell proliferation in the central nervous system of an adult semiterrestrial crab.

Neurogenesis occurs in adults of most organisms, both vertebrates and invertebrates. In semiterrestrial crabs of the infraorder Brachyura, the deutocerebrum, where neurogenesis occurs, processes the olfactory sensory information from the antennae. The deutocerebrum is composed of a pair of olfactory lobes associated with cell clusters 9 and 10 (Cl 9 and Cl 10), containing proliferating cells. Because the location of the neurogenic niche in brachyuran semiterrestrial crabs has not been defined, here we describe a neurogenic niche in the central olfactory system of the crab Ucides cordatus and report two types of glial cells in the deutocerebrum, based on different markers. Serotonin (5-hydroxytryptamine) labeling was used to reveal neuroanatomical aspects of the central olfactory system and the neurogenic niche. The results showed a zone of proliferating neural cells within Cl 10, which also contains III beta-tubulin (Tuj1)+ immature neurons, associated with a structure that has characteristics of the neurogenic niche. For the first time, using two glial markers, glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS), we identified two types of astrocyte-like cells in different regions of the deutocerebrum. This study adds to the understanding of neurogenesis in a brachyuran semiterrestrial crustacean and encourages comparative studies between crustaceans and vertebrates, including mammals, based on shared aspects of both mechanisms of neurogenesis and regenerative potentials.

Biochemical Characterization and Allosteric Modulation by Magnesium of (Na+, K+)-ATPase Activity in the Gills of the Red Mangrove Crab Goniopsis cruentata (Brachyura, Grapsidae).

We provide a kinetic characterization of (Na+, K+)-ATPase activity in a posterior gill microsomal fraction from the grapsid crab Goniopsis cruentata. (Na+, K+)-ATPase activity constitutes 95% of total ATPase activity, and sucrose density centrifugation reveals an ATPase activity peak between 25 and 35% sucrose, distributed into two, partially separated protein fractions. The (Na+, K+)-ATPase α-subunit is localized throughout the ionocyte cytoplasm and has an Mr of ≈ 10 kDa and hydrolyzes ATP obeying cooperative kinetics. Low (VM = 186.0 ± 9.3 nmol Pi min-1 mg-1 protein and K0.5 = 0.085 ± 0.004 mmol L-1) and high (VM = 153.4 ± 7.7 nmol Pi min-1 mg-1 protein and K0.5 = 0.013 ± 0.0006 mmol L-1) affinity ATP binding sites were characterized. At low ATP concentrations, excess Mg2+ stimulates the enzyme, triggering exposure of a high-affinity binding site that accounts for 50% of (Na+, K+)-ATPase activity. Stimulation by Mg2+ (VM = 425.9 ± 25.5 nmol Pi min-1 mg-1 protein, K0.5 = 0.16 ± 0.01 mmol L-1), K+ (VM = 485.3 ± 24.3 nmol Pi min-1 mg-1 protein, K0.5 = 0.9 ± 0.05 mmol L-1), Na+ (VM = 425.0 ± 23.4 nmol Pi min-1 mg-1 protein, K0.5 = 5.1 ± 0.3 mmol L-1) and NH4+ (VM = 497.9 ± 24.9 nmol Pi min-1 mg-1 protein, K0.5 = 9.7 ± 0.5 mmol L-1) obeys cooperative kinetics. Ouabain inhibits up to 95% of ATPase activity with KI = 196.6 ± 9.8 µmol L-1. This first kinetic characterization of the gill (Na+, K+)-ATPase in Goniopsis cruentata enables better comprehension of the biochemical underpinnings of osmoregulatory ability in this semi-terrestrial mangrove crab.

Magnetite nanoparticles coated with oleic acid: accumulation in hepatopancreatic cells of the mangrove crab Ucides cordatus.

The field of nanotechnology had enormous developments, resulting in new methods for the controlled synthesis of a wide variety of nanoscale materials with unique properties. Efficient methods such as thermal decomposition for efficient size control have been developed in recent years for the synthesis of oleic acid (OA)-coated magnetite (Fe3O4) nanoparticles (MNP-OA). These nanostructures can be a source of pollution when emitted in the aquatic environment and could be accumulated by vulnerable marine species such as crustaceans. In this work, we synthesized and characterized MNP-OA of three different diameters (5, 8, and 12 nm) by thermal decomposition. These nanoparticles were remarkably stable after treatment with high affinity iron chelators (calcein, fluorescent desferrioxamine, and fluorescent apotransferrin); however, they displayed pro-oxidant activity after being challenged with ascorbate under two physiological buffers. Free or nanoparticle iron displayed low toxicity to four types of hepatopancreatic cells (E, R, F, and B) of the mangrove crab Ucides cordatus; however, they were promptly bioavailable, posing the risk of ecosystem disruption due to the release of excess nutrients.

Evaluation of iron loading in four types of hepatopancreatic cells of the mangrove crab Ucides cordatus using ferrocene derivatives and iron supplements.

The mangrove crab Ucides cordatus is a bioindicator of aquatic contamination. In this work, the iron availability and redox activity of saccharide-coated mineral iron supplements (for both human and veterinary use) and ferrocene derivatives in Saline Ucides Buffer (SUB) medium were assessed. The transport of these metallodrugs by four different hepatopancreatic cell types (embryonic (E), resorptive (R), fibrillar (F), and blister (B)) of U. cordatus were measured. Organic coated iron minerals (iron supplements) were stable against strong chelators (calcein and transferrin). Ascorbic acid efficiently mediated the release of iron only from ferrocene compounds, leading to redox-active species. Ferrous iron and iron supplements were efficient in loading iron to all hepatopancreatic cell types. In contrast, ferrocene derivatives were loaded only in F and B cell types. Acute exposition to the iron compounds resulted in cell viability of 70-95%, and to intracellular iron levels as high as 0.40 µmol L-1 depending upon the compound and the cell line. The easiness that iron from iron metallodrugs was loaded/transported into U. cordatus hepatopancreatic cells reinforces a cautionary approach to the widespread disposal and use of highly bioavailable iron species as far as the long-term environmental welfare is concerned.

A Kinetic Characterization of the Gill (Na+, K+)-ATPase from the Semi-terrestrial Mangrove Crab Cardisoma guanhumi Latreille, 1825 (Decapoda, Brachyura).

We provide a kinetic characterization of (Na+, K+)-ATPase activity in a posterior gill microsomal fraction from the semi-terrestrial mangrove crab Cardisoma guanhumi. Sucrose density gradient centrifugation reveals two distinct membrane fractions showing considerable (Na+, K+)-ATPase activity, but also containing other microsomal ATPases. The (Na+, K+)-ATPase, notably immuno-localized to the apical region of the epithelial pillar cells, and throughout the pillar cell bodies, has an M r of around 110 kDa and hydrolyzes ATP with V M = 146.8 ± 6.3 nmol Pi min-1 mg protein-1 and K M = 0.05 ± 0.003 mmol L-1 obeying Michaelis-Menten kinetics. While stimulation by Na+ (V M = 139.4 ± 6.9 nmol Pi min-1 mg protein-1, K M = 4.50 ± 0.22 mmol L-1) also follows Michaelis-Menten kinetics, modulation of (Na+, K+)-ATPase activity by MgATP (V M = 136.8 ± 6.5 nmol Pi min-1 mg protein-1, K 0.5 = 0.27 ± 0.04 mmol L-1), K+ (V M = 140.2 ± 7.0 nmol Pi min-1 mg protein-1, K 0.5 = 0.17 ± 0.008 mmol L-1), and NH4+ (V M = 149.1 ± 7.4 nmol Pi min-1 mg protein-1, K 0.5 = 0.60 ± 0.03 mmol L-1) shows cooperative kinetics. Ouabain (K I = 52.0 ± 2.6 µmol L-1) and orthovanadate (K I = 1.0 ± 0.05 µmol L-1) inhibit total ATPase activity by around 75%. At low Mg2+ concentrations, ATP is an allosteric modulator of the enzyme. This is the first study to provide a kinetic characterization of the gill (Na+, K+)-ATPase in C. guanhumi, and will be useful in better comprehending the biochemical underpinnings of osmoregulatory ability in a semi-terrestrial mangrove crab.

Cytochemical characterization of gill and hepatopancreatic cells of the crab Ucides cordatus (Crustacea, Brachyura) validated by cell metal transport / Caracterização citoquímica de células de brânquias e hepatopâncreas de Ucides cordatus (Crustacea, Brachyura) validado por transporte celular de metais

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.

Ucides cordatus (Linnaeus, 1763) é um caranguejo de mangue hiper-hipo-regulador que possui brânquias responsáveis por processos respiratórios e osmorregulatórios. Apresentam também hepatopâncreas, que realizam digestão, absorção de nutrientes e detoxificação de metais tóxicos. Cada um desses órgãos possui células específicas que são importantes para estudos in vitro em biologia celular e transporte de íons e metais tóxicos. Visando estudar e caracterizar as células de cada órgão, estas foram separadas em um gradiente de sacarose (SG) de 10 a 40% e as células de cada gradiente foram caracterizadas usando o marcador de mitocôndria DASPEI (2-(4-dimethylaminostyryl)-N- ethylpyridinium iodide) e o corante Tricromo de Mallory. No SG de 20 e 40% para células branquiais e 30% para células hepatopancreáticas, foi observado um maior número de células coradas com DASPEI, indicando um maior número de mitocôndrias nessas células. Conclui-se que células branquiais presentes no SG de 20 e 40% são “Thin cells”, responsáveis por processos respiratórios, e Ionócitos, responsáveis pelo transporte iônico, respectivamente. Para as células hepatopancreáticas, o SG de 30% é composto de células Fibrilares que possuem um maior número de transportadores de membrana para íons e nutrientes. Adicionalmente, o transporte do metal tóxico cádmio (Cd) em células hepatopancreáticas isoladas foi realizado para testar a integridade fisiológica das células isoladas e estudar o transporte entre os diferentes tipos celulares. Todas as células hepatopancreáticas transportaram Cd. Os resultados obtidos são um primeiro passo para trabalhos adicionais em células isoladas de importantes epitélios de troca em caranguejos, utilizando um método de separação simples e visando futuros estudos com cultura de células em caranguejos.

Cytochemical characterization of gill and hepatopancreatic cells of the crab Ucides cordatus (Crustacea, Brachyura) validated by cell metal transport / Caracterização citoquímica de células de brânquias e hepatopâncreas de Ucides cordatus (Crustacea, Brachyura) validado por transporte celular de metais

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 Mallorys 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.(AU)

Ucides cordatus (Linnaeus, 1763) é um caranguejo de mangue hiper-hipo-regulador que possui brânquias responsáveis por processos respiratórios e osmorregulatórios. Apresentam também hepatopâncreas, que realizam digestão, absorção de nutrientes e detoxificação de metais tóxicos. Cada um desses órgãos possui células específicas que são importantes para estudos in vitro em biologia celular e transporte de íons e metais tóxicos. Visando estudar e caracterizar as células de cada órgão, estas foram separadas em um gradiente de sacarose (SG) de 10 a 40% e as células de cada gradiente foram caracterizadas usando o marcador de mitocôndria DASPEI (2-(4-dimethylaminostyryl)-N- ethylpyridinium iodide) e o corante Tricromo de Mallory. No SG de 20 e 40% para células branquiais e 30% para células hepatopancreáticas, foi observado um maior número de células coradas com DASPEI, indicando um maior número de mitocôndrias nessas células. Conclui-se que células branquiais presentes no SG de 20 e 40% são “Thin cells”, responsáveis por processos respiratórios, e Ionócitos, responsáveis pelo transporte iônico, respectivamente. Para as células hepatopancreáticas, o SG de 30% é composto de células Fibrilares que possuem um maior número de transportadores de membrana para íons e nutrientes. Adicionalmente, o transporte do metal tóxico cádmio (Cd) em células hepatopancreáticas isoladas foi realizado para testar a integridade fisiológica das células isoladas e estudar o transporte entre os diferentes tipos celulares. Todas as células hepatopancreáticas transportaram Cd. Os resultados obtidos são um primeiro passo para trabalhos adicionais em células isoladas de importantes epitélios de troca em caranguejos, utilizando um método de separação simples e visando futuros estudos com cultura de células em caranguejos. (AU)

Mangrove sedimentary characteristics and implications for crab Ucides cordatus (Crustacea, Decapoda, Ucididae) distribution in an estuarine area of the Amazonian region / Características sedimentares de manguezal e implicações para a distribuição do caranguejo-uçá Ucides cordatus (Crustacea, Decapoda, Ucididae) em uma área estuarina amazônica

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.(AU)

Na zona costeira, sedimentos, água e organismos interagem intensamente. Nas costas equatoriais dominadas por maré os manguezais são abundantes. Estas áreas são conhecidas por sua importância ecológica. No caso dos manguezais da costa atlântica da América do Sul o caranguejo-uçá Ucides cordatus (Linnaeus, 1763) se destaca por sua relevância ecológica e econômica, sendo que altas densidades deste organismo são encontradas na zona costeira amazônica. O presente estudo investiga a distribuição de sedimentos nos manguezais de Bragança (costa Amazônica, Brasil) e suas correlações com a vegetação e a distribuição do caranguejo-uçá. Quarenta e sete amostras de sedimento foram avaliadas, assim como caranguejos de 8 destas áreas foram coletados, onde o tipo dominante de vegetação foi também identificado. Os resultados demonstram que os sedimentos superficiais, assim como no extrato 0,8 a 1 m de profundidade, na área são principalmente compostos por silte (59%), incluindo em média 21% de areia e 20% de argila. O tipo de vegetação predominante foi significativamente correlacionado com a abundância e tamanho/peso dos caranguejos. As características sedimentares também foram substancialmente diferentes dependendo da vegetação. Áreas dominadas por Avicennia germinans tiveram mais areia e argila que as áreas dominadas por Rizophora mangle, onde a fração silte prevalece grandemente e os caranguejos eram significativamente maiores e mais abundantes. Os resultados demonstraram que sedimentos, invertebrados bentônicos e vegetação estão intimamente relacionados nos manguezais e devem ser estudados de maneira integrada.(AU)

Mangrove sedimentary characteristics and implications for crab Ucides cordatus (Crustacea, Decapoda, Ucididae) distribution in an estuarine area of the Amazonian region / Características sedimentares de manguezal e implicações para a distribuição do caranguejo-uçá Ucides cordatus (Crustacea, Decapoda, Ucididae) em uma área estuarina amazônica

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.

Na zona costeira, sedimentos, água e organismos interagem intensamente. Nas costas equatoriais dominadas por maré os manguezais são abundantes. Estas áreas são conhecidas por sua importância ecológica. No caso dos manguezais da costa atlântica da América do Sul o caranguejo-uçá Ucides cordatus (Linnaeus, 1763) se destaca por sua relevância ecológica e econômica, sendo que altas densidades deste organismo são encontradas na zona costeira amazônica. O presente estudo investiga a distribuição de sedimentos nos manguezais de Bragança (costa Amazônica, Brasil) e suas correlações com a vegetação e a distribuição do caranguejo-uçá. Quarenta e sete amostras de sedimento foram avaliadas, assim como caranguejos de 8 destas áreas foram coletados, onde o tipo dominante de vegetação foi também identificado. Os resultados demonstram que os sedimentos superficiais, assim como no extrato 0,8 a 1 m de profundidade, na área são principalmente compostos por silte (59%), incluindo em média 21% de areia e 20% de argila. O tipo de vegetação predominante foi significativamente correlacionado com a abundância e tamanho/peso dos caranguejos. As características sedimentares também foram substancialmente diferentes dependendo da vegetação. Áreas dominadas por Avicennia germinans tiveram mais areia e argila que as áreas dominadas por Rizophora mangle, onde a fração silte prevalece grandemente e os caranguejos eram significativamente maiores e mais abundantes. Os resultados demonstraram que sedimentos, invertebrados bentônicos e vegetação estão intimamente relacionados nos manguezais e devem ser estudados de maneira integrada.

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 / Diferentes rotas de desenvolvimento larval do caranguejo Ucides cordatus (Decapoda, Ocypodidae) e sua relação com altas taxas de mortalidade no fim de larviculturas massivas

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.

Um dos fatores mais limitantes que afetam o cultivo larval de Ucides cordatus (Linnaeus, 1763) em laboratório é um período de alta mortalidade, o qual usualmente ocorre no fim do curso da larvicultura durante a metamorfose da fase de zoea para a de megalopa. O objetivo da presente pesquisa foi analisar o desenvolvimento pósembrionário de U. cordatus em uma base individual e, em particular, procurar por padrões ligando distúrbios no processo de muda com as altas taxas de mortalidade observadas nas larviculturas massivas. Um total de 50 larvas foram cultivadas individualmente da eclosão até a fase de megalopa em condições controladas, alimentadas com uma combinação de microalgas e rotíferos. A taxa de sobrevivência foi de 70% até zoea V. As 35 larvas zoea V sobreviventes seguiram dois diferentes caminhos. Onze realizaram a metamorfose diretamente para megalopa, dezoito mudaram para zoea VI e seis morreram como zoea V. No último evento de muda, apenas duas larvas zoea VI atingiram a fase de megalopa, enquanto as dezesseis restantes morreram. Em investigação posterior sob microscópio, 13 das zoea VI mortas mostravam características de estágio de prémuda e pereiópodes desproporcionalmente grandes em relação à carapaça. O padrão observado lembra a Síndrome da Morte na Muda (MDS) descrita para outras espécies de decápodes, na qual larvas morrem no fim da fase de prémuda do ciclo de mudas. Nós sugerimos que larvas de U. cordatus desenvolvem distúrbios no processo de muda similares à MDS descrita para outras espécies e que esses distúrbios são relacionados a um caminho mais complexo que envolve a ocorrência do estágio larval zoea VI.

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 / Diferentes rotas de desenvolvimento larval do caranguejo Ucides cordatus (Decapoda, Ocypodidae) e sua relação com altas taxas de mortalidade no fim de larviculturas massivas

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.(AU)

Um dos fatores mais limitantes que afetam o cultivo larval de Ucides cordatus (Linnaeus, 1763) em laboratório é um período de alta mortalidade, o qual usualmente ocorre no fim do curso da larvicultura durante a metamorfose da fase de zoea para a de megalopa. O objetivo da presente pesquisa foi analisar o desenvolvimento pósembrionário de U. cordatus em uma base individual e, em particular, procurar por padrões ligando distúrbios no processo de muda com as altas taxas de mortalidade observadas nas larviculturas massivas. Um total de 50 larvas foram cultivadas individualmente da eclosão até a fase de megalopa em condições controladas, alimentadas com uma combinação de microalgas e rotíferos. A taxa de sobrevivência foi de 70% até zoea V. As 35 larvas zoea V sobreviventes seguiram dois diferentes caminhos. Onze realizaram a metamorfose diretamente para megalopa, dezoito mudaram para zoea VI e seis morreram como zoea V. No último evento de muda, apenas duas larvas zoea VI atingiram a fase de megalopa, enquanto as dezesseis restantes morreram. Em investigação posterior sob microscópio, 13 das zoea VI mortas mostravam características de estágio de prémuda e pereiópodes desproporcionalmente grandes em relação à carapaça. O padrão observado lembra a Síndrome da Morte na Muda (MDS) descrita para outras espécies de decápodes, na qual larvas morrem no fim da fase de prémuda do ciclo de mudas. Nós sugerimos que larvas de U. cordatus desenvolvem distúrbios no processo de muda similares à MDS descrita para outras espécies e que esses distúrbios são relacionados a um caminho mais complexo que envolve a ocorrência do estágio larval zoea VI.(AU)

Survival of Ucides cordatus (Decapoda: Ocypodidae) megalopae during transport under different conditions of density and duration

Target areas for Ucides cordatus (Linnaeus, 1763) restocking programs are often located far from the laboratory where larval rearing is developed. During translocation, the larvae are submitted to highly stressful conditions due to handling, packing, and transport activities. The aim of the present study was to assess the mortality rates of U. cordatus megalopae caused by different transportation procedures. Megalopae at loading densities of 50, 150, and 300 ind.L-1 were packed in double polyethylene 12 x 25 cm plastic bags with 200 ml of marine water at salinity 30. The bags were filled with oxygen at a proportion of 1:2 parts of water and sealed tightly. The trepidations during transport were simulated by the use of a shaker device (800 vibrations/minute) over periods of three and six hours inside a dark container. The survivorship rates of larvae after simulation were compared to those obtained in control groups, which consisted of plastic vials with megalopae at a loading density of 50 ind.L-1 maintained at rest. Immediately after the two transport simulations, there was no significant difference in survivorship between the treatments and the control. However, 24 hours after simulation some of the tested densities resulted in significantly lower survivorships. The results demonstrated that U. cordatus megalopae can tolerate six hours of shaking during transportation, at high densities with minimal mortality.

Survival of Ucides cordatus (Decapoda: Ocypodidae) megalopae during transport under different conditions of density and duration

Target areas for Ucides cordatus (Linnaeus, 1763) restocking programs are often located far from the laboratory where larval rearing is developed. During translocation, the larvae are submitted to highly stressful conditions due to handling, packing, and transport activities. The aim of the present study was to assess the mortality rates of U. cordatus megalopae caused by different transportation procedures. Megalopae at loading densities of 50, 150, and 300 ind.L-1 were packed in double polyethylene 12 x 25 cm plastic bags with 200 ml of marine water at salinity 30. The bags were filled with oxygen at a proportion of 1:2 parts of water and sealed tightly. The trepidations during transport were simulated by the use of a shaker device (800 vibrations/minute) over periods of three and six hours inside a dark container. The survivorship rates of larvae after simulation were compared to those obtained in control groups, which consisted of plastic vials with megalopae at a loading density of 50 ind.L-1 maintained at rest. Immediately after the two transport simulations, there was no significant difference in survivorship between the treatments and the control. However, 24 hours after simulation some of the tested densities resulted in significantly lower survivorships. The results demonstrated that U. cordatus megalopae can tolerate six hours of shaking during transportation, at high densities with minimal mortality.

Survival of Ucides cordatus (Decapoda: Ocypodidae) megalopae during transport under different conditions of density and duration

Target areas for Ucides cordatus (Linnaeus, 1763) restocking programs are often located far from the laboratory where larval rearing is developed. During translocation, the larvae are submitted to highly stressful conditions due to handling, packing, and transport activities. The aim of the present study was to assess the mortality rates of U. cordatus megalopae caused by different transportation procedures. Megalopae at loading densities of 50, 150, and 300 ind.L-1 were packed in double polyethylene 12 x 25 cm plastic bags with 200 ml of marine water at salinity 30. The bags were filled with oxygen at a proportion of 1:2 parts of water and sealed tightly. The trepidations during transport were simulated by the use of a shaker device (800 vibrations/minute) over periods of three and six hours inside a dark container. The survivorship rates of larvae after simulation were compared to those obtained in control groups, which consisted of plastic vials with megalopae at a loading density of 50 ind.L-1 maintained at rest. Immediately after the two transport simulations, there was no significant difference in survivorship between the treatments and the control. However, 24 hours after simulation some of the tested densities resulted in significantly lower survivorships. The results demonstrated that U. cordatus megalopae can tolerate six hours of shaking during transportation, at high densities with minimal mortality.

Length-weight relationship and condition factor of the mangrove crab Ucides cordatus (Linnaeus, 1763) (Crustacea, Brachyura, Ucididae)

The relationship of wet weight (WT) to cephalothorax width (CW) and temporal and seasonal variations in the condition factor were analyzed for each sex of the mangrove crab Ucides cordatus, using specimens collected monthly from September 1998 through September 2000, at Iguape, state of São Paulo. The WT/CW relationship, determined by the regression analysis and the condition factor were evaluated individually, monthly and seasonally, for each sex. The WT/CW relationship indicated isometric growth in males and negative allometric growth in females. Body weight was higher in males than in females of equivalent size and this difference was associated with the males' faster growth and heavier chelipeds. On the other hand, the means for condition factor were always higher for females than for males; the mean condition factor was lower in spring and summer and higher in autumn and winter.

A determinação da relação do peso úmido (WT) pela largura cefalotorácica (CW) do caranguejo U. cordatus e a análise da dinâmica temporo-sazonal do fator de condição foram realizadas com machos e fêmeas coletados mensalmente no período de 1998/2000, em Iguape (SP). A relação WT/CW foi determinada por análise de regressão, enquanto o fator de condição foi determinado individualmente para cada animal, bem como pela média mensal e sazonal para cada sexo. A relação WT/CW evidenciou um crescimento isométrico nos machos e alométrico negativo nas fêmeas, indicando que os machos atingem um peso corpóreo superior ao das fêmeas para um mesmo tamanho de referência. Tal fato está associado ao maior crescimento e peso dos quelípodos do macho. As médias do fator de condição das fêmeas foram maiores que as dos machos. Os menores valores do fator de condição ocorreram durante a primavera e verão, atingindo os maiores níveis durante o outono e inverno.