ABSTRACT
ABSTRACT Objective. The sex ratio, proportion of ovigerous females, length at sexual maturity and fecundity of Grapsus grapsus crabs in the Lobos, Venados and Pajaros islands (southeastern Gulf of California) were analyzed. Materials and methods. Sampling was conducted monthly between March 2011 and February 2012, during the night at low tide. Thirty crabs were collected in a quadrant (25 m2) at each sampling site on each island. cw (mm) and w (g) were determined. The sex ratio and size at sexual maturity (cw50%) were estimated, and for ovigerous females, embryonic stages and fecundity (gravimetric method) were determined. Results. The sex ratio (M:F) was 1:1.3. The average size at sexual maturity (cw50%) was 34.9 mm. The majority of females were ovigerous (71.3%), and 48% of the embryos of ovigerous females were at the red-orange phase. Egg diameter ranged from 1.1 to 5 µm, with an average of 2.05 µm. The mean fecundity was 24339.3 eggs. The maximum and minimum weight of ovigerous females was 69.9 and 15.2 g. Conclusions. The studied characteristics of sex ratio, proportion of ovigerous females, length at sexual maturity and fecundity of G. grapsus, indicate the effective administration and management of this resource in this area.
RESUMEN Objetivo. Se analizó la proporción de sexos, hembras ovígeras, talla de primera madurez sexual y fecundidad del cangrejo roca Grapsus grapsus en islas Lobos, Venados y Pájaros (sureste del Golfo de California). Material y métodos. Los muestreos fueron mensuales entre marzo 2011 y febrero 2012, las colectas fueron nocturnas durante la bajamar, se obtuvieron en un cuadrante (25 m2) por isla 30 organismos al azar, se les determinó el AN (mm) y PT (g). Se estimó la proporción de sexos y talla de primera madurez sexual (AN50%), se analizaron en hembras grávidas, las fases embrionarias y la fecundidad (método gravimétrico). Resultados. La proporción de M:H fue 1:1.3. La talla media de primera madurez fue AN50% 34.9 mm. Es evidente la presencia de hembras ovígeras (71.3%) y todas las fases embrionarias, la fase rojo-naranja fue la mayor representada en 48%. La variación del diámetro del huevo fue 1.1 a 5 µm y el promedio de 3.05 µm. La fecundidad media fue 24339.3 cigotos. El máximo y mínimo peso de hembras ovígeras fue 69.9 y 15.2 g, respectivamente. Conclusiones. Con base a las características biológicas del recurso tales como la proporción de sexos, hembras ovígeras, talla de primera madurez sexual y fecundidad en la población de G. grapsus, representa un efecto favorable en su posterior administración y manejo de este recurso en esta zona.
Subject(s)
Animals , Reproduction , Decapoda , Xiphosura americanaABSTRACT
Deformidades e anormalidades em crustáceos têm sido associadas a fatores genéticos, problemas ocorridos durante a muda, danos causados por ectobiontes, predadores ou estresse ambiental causado por produtos químicos. Espécimes de caranguejos coletados no litoral de São Paulo apresentaram anormalidades no corpo. Estes caranguejos pertencem às seguintes espécies: Callinectes ornatus (Ordway, 1863), Arenaeus cribrarius (Lamarck, 1818) e Leurocyclus tuberculosus (H. Milne Edwards & Lucas, 1843). As coletas foram realizadas por meio de arrastos camaroneiros em julho de 2008, agosto e outubro de 2009, na região de Ubatuba, Estado de São Paulo, Brasil. As anormalidades apresentadas no corpo dos caranguejos encontravam-se no dáctilo do quelípodo (C. ornatus macho adulto), defeitos na carapaça (A. cribrarius macho adulto) e alterações abdominais (C. ornatus fêmea adulta; L. tuberculosus macho adulto e fêmea ovígera). O registro de tais ocorrências pode servir na distinção de alterações causadas naturalmente ou por impacto humano, podendo fornecer ferramentas úteis no sentido de monitorar áreas ambientais não protegidas, bem como trazer subsídios ao entendimento de alterações não usuais ocorridas durante a ontogenia de espécies importantes para a comunidade bentônica.
Deformities and abnormalities in crustaceans have been associated to genetic problem, which occurred during molt process, damage caused by ectobionts, predators or environmental stress caused by chemical wastes. Some crab specimens collected in the São Paulo littoral were found having body abnormalities. They belong to the following crab species: Callinectes ornatus (Ordway, 1863), Arenaeus cribrarius (Lamarck, 1818) and Leurocyclus tuberculosus (H. Milne Edwards; Lucas, 1843). Samplings were performed by trawling during July 2008, August and October 2009 at the Ubatuba region, São Paulo State, Brazil. Body abnormalities were verified in the cheliped dactyl (C. ornatus an adult male), carapace deformities (A. cribrarius an adult male) and abdominal alterations (C. ornatus an adult female; L. tuberculosus an adult male and an ovigerous female). The record and analysis of such occurrences can help in the distinction of natural or human impact caused alterations. In this way, the occurrence study of this kind of body alterations could provide tools in order to control unprotected environmental areas, as well as bring subsides to understand the unusual variations during the ontogeny of important species in the benthic community.
Subject(s)
Animals , Congenital Abnormalities , Xiphosura americana , Animal ShellsABSTRACT
O presente trabalho estudou o efeito da salinidade na sobrevivência e na duração do desenvolvimento larval do caranguejo-uçá, Ucides cordatus (do estuário do Rio Caeté, Norte do Brasil), até a fase de megalopa em sete tratamentos de salinidade (0, 5, 10, 15, 20, 25 e 30). A salinidade afetou significativamente a sobrevivência das larvas zoea, no entanto não afetou a duração do desenvolvimento larval (20,77 ± 1,56 dias). Nas salinidades 0, 5 e 10 houve total mortalidade das larvas zoea. Somente a partir da salinidade 15 observou-se um desenvolvimento completo até a fase de megalopa. A taxa de sobrevivência foi maior em salinidade 30 (72 por cento) e menor em 15 (16 por cento). A reduzida taxa de sobrevivência das larvas zoea de U. cordatus, em salinidades baixas, indica a necessidade de dispersão larval do estuário para as águas costeiras onde as condições de salinidade para o desenvolvimento larval são mais favoráveis. Caso contrário se não houvesse a dispersão, a reduzida salinidade das águas estuarinas no período chuvoso, causaria uma elevada mortalidade, afetando desta forma o recrutamento, a manutenção e o crescimento da população de U. cordatus nos manguezais.
The present work studied the effect of salinity on the survival and duration of larval development of the mangrove crab, Ucides cordatus (from the Caeté River estuary, North of Brazil) until the megalopal phase in seven salinity treatments (0, 5, 10, 15, 20, 25 e 30). Salinity significantly affected the survival of the zoea larvae, however it did not affect the duration of the larval development (20.77 ± 1.56 days). In salinity 0, 5 and 10 all zoea larvae died. Only from off salinity 15, complete development until the megalopal phase occurred. The survival rate was highest in salinity 30 (72 percent) and lowest in 15 (16 percent). The reduced survival rate of the U. cordatus zoea larvae, in low salinities, indicates the necessity of larval dispersion from the estuary to coastal waters, where salinity conditions for larval development are more favorable. Otherwise, if there was no dispersion, the reduced salinity of estuarine waters in the rainy season would cause a high mortality thereby affecting the recruitment, maintenance and growth of the U. cordatus population in the mangroves.
Subject(s)
Xiphosura americana , Salinity , SurvivorshipABSTRACT
The crab Heterocrypta tommasii (Decapoda: Parthenopidae): an addition to the carcinofauna of Venezuela. The crab Heterocrypta tommasii Rodrigues da Costa, 1959 is reported for the first time from Venezuelan marine waters and its main taxonomical features are presented and illustrated. This report extends the range from Colombia, Guyana and Brazil; is the first report of the genus for Venezuela, and increases to six the number of Parthenopidae species known from the country. Rev. Biol. Trop. 54 (Suppl. 3): 131-134. Epub 2007 Jan. 15.
Se registra por primera vez en aguas marinas venezolanas la presencia del cangrejo Heterocrypta tommasii y se presentan las principales características del espécimen estudiado. Este hallazgo amplía la distribución conocida de la especie (la cual sólo contemplaba Colombia, Guayana y Brasil), establece el primer registro del género Heterocrypta en Venezuela e incrementa a seis el número de especies conocidas de Parthenopidae para este país.
Subject(s)
Decapoda/anatomy & histology , Xiphosura americana , VenezuelaABSTRACT
A case of bilateral cheliped hypertrophya crab Uca cumulanta (Decapoda: Ocypodidae). An adult male of Uca cumulanta with bilateral cheliped hypertrophy was found during a collection of crabs at La Restinga Lagoon, Margarita Island, Venezuela. Both chelipeds were sub equal in size, regarding the major cheliped of a normal male. Rev. Biol. Trop. 54 (Suppl. 3): 117-119. Epub 2007 Jan. 15.
Un macho de Uca cumulanta con hipertrofia bilateral de quelas fue capturado durante en la Laguna de La Restinga, Isla de Margarita, Venezuela. Ambas quelas eran subiguales en tamaño y se asemejaban al quelípedo mayor de los machos normales.
Subject(s)
Animals , Decapoda/anatomy & histology , Xiphosura americana , Congenital AbnormalitiesABSTRACT
An ecologic study on Paragonimus in Malaysia was attempted from May to September 1967. Seven streams located in various directions and distances from Kuala Lumpur were surveyed for the study of intermediate hosts, snail and crab. One Malayan village and one aborigine village where infected crabs were found, and two tuberculosis hospitals in K.L. were surveyed for the study of human population. Intradermal tests along with sputum or stool examination to detect human infection by Paragonimus were employed. Wild animals, only a few, were shot in the vicinity of the aborigine village and several domestic cats from the Malayan village were bought. These animals were autopsied and examined for adult Paragonimus. Among five species of crab collected from the study areas, only two species, Potamon jahorenes and Parathelphusa maculata were found to be infected with Paragonimus. P. maculata seemed to be better crab host for the Paragonimus because this species had higher infection rate and metacercarial density than the other in the very same area. Three out of seven streams had infected crabs and the infection rate as well as the infection intensity varied from one stream to another. Only avilable snail in the streams was identified as Brotia costula. The infection rate of the snail was very low, six snails out of 11,898, which is about the same rate reported from other countries. Infected snail, however, had thousands of rediae uncountable containing about twelve microcercocercariae in each redia, sufficient enough to maintain the life cycle of the parasite even with only a few infected snail, the amplifier. This is the first confirmed report on the snail host of Paragonimus from Malaysia where the existence of Paragonimus had been reported in 1923. The first trial to study human population by means of intradermal test, sputum and/or stool examinations in Malaysia showed no evidence of human infection of Paragonimus. The number of animals, wild and domestic, examined for natural infection was too small to draw any statement. These examined animals were all negative for adult Paragonimus. Even though more extensive studies on wild animals and human population may be necessary for the definite conclusion, the facts that infected crabs from jungle stream where human contacts are extreamely rare, and also highly infected crabs from the area where none of humans or domestic animals were infected, strongly suggest the life cycle of Paragonimus in this area may be maintained by wild animal hosts rather than by human host. The morphology of all stages of the parasite, the pattern of penetrating glands, flame cells and excretroy bladder of cercaria, lancet shaped single cuticular spines and 6 branched ovary of adult worm obtained from experimentally infected cat, and the shape of egg including all measurements agree well with the characteristics of Paragonimus westermani.
Subject(s)
Paragonimus westermani , Xiphosura americana , CatsABSTRACT
Mathematical models such as the negative binomial, Poisson and Polya-Eggenberger distributions were applied to the observed data of the number of metacercariae of Paragonimus iloktsuenensis in crab hosts, Sesarma dehaani which were collected in Hadong, South Kyong-sang Do, Korea. From the above analysis, it was found that the pattern of density of metacercariae of this lungfluke among the crab hosts was well fitted to the negative binomial distribution, rather than to the Poisson or Polya-Eggenberger distribution.
Subject(s)
Epidemiology , Mathematics , Metacercariae , Xiphosura americanaABSTRACT
A study on the infection status of intermediate hosts of Paragonimus, snail and crab, was conducted on Che Ju Island for four years to understand ecology of Paragonimus in the area and to evalute the control program by mass chemotherapy The infection rate of the first intermediate host of Paragonimus, snail, showed higher rate in the area where human association was more frequent and had higher human infection rate compared with the area with lower human infection and less contact by people. Larger snails were infected more frequently than smaller ones. After the mass treatment on human population, the infection rate of snail dropped markedly in four years. The infection rate and the intensity of infection of crabs were influenced by many factors:by frequency of human association, by prevalence of paragonimiasis in the population and volume of water flow, dilution effect. The distribution of metacercariae in infected crabs varied by body sites; the most frequently in gill, next in legs, internal organs and thoracic muscle in order. If crabs were examined for existence of metacercariae only gills, about 6% of infected crabs of may be missed as negative. The infection status of the crabs was not different by distance from the actual site of pollution. Also seasonal fluctuation of crab infection was not remakable. The crab infection by size showed time sequence of exposure; smaller crabs had lower infection rate and metacercaria density reaching to the maximum by 3 cm of size. As shown in the snail infection, the crab infection remarkably decreased after the control measure of human paragonimiasis, mass chemotherapy, in four years.
Subject(s)
Paragonimiasis , Paragonimus westermani , Metacercariae , Epidemiology , Snails , Xiphosura americana , Drug TherapyABSTRACT
Metacercariae of a kind of Levinseniella species were found from a brackish water crabs, Macrophthalmus japonicus de Haan, in the brackish area of Hyungsan river of Kyungpook province. Habitats were the epigastric and progastric regions of Macrophthalmus japonicus. One hundred and seventy five crabs out of 178 examined (98.3 per cent) were infested with metacercariae of Levinseniella species. The infested number of metacercariae in each crabs was average 100 ea. The excystation of metacercaria has not developed in vitro (both saline and tyrode's solution). Many eggs were observed in the metacercariae maintained for 24 or 48 hours in the water-bath. No differences were observed between semi-adult fluke from rat host and those maintained for 24 or 48 hours in vitro.