- Highly motivate Aquatic biologist, curious taxonomist and extreme ecologist of invertebratesedit
Se evaluaron las fluctuaciones poblacionales, desde diciembre de 1995 hasta agosto de 1996, de los bivalvos Donax striatus Linne, 1767 and Tivela mactroides (Born, 1778) en dos playas arenosas (Caimare Chico y Cano Sagua), localizadas en... more
Se evaluaron las fluctuaciones poblacionales, desde diciembre de 1995 hasta agosto de 1996, de los bivalvos Donax striatus Linne, 1767 and Tivela mactroides (Born, 1778) en dos playas arenosas (Caimare Chico y Cano Sagua), localizadas en la costa suroccidental del Golfo de Venezuela, estado Zulia, Venezuela. D. striatus presento en promedio una alta abundancia (Caimare Chico: 295.84 ind/m 2 ; Cano Sagua: 92,63 ind/m 2 ) en comparacion con T. mactroides (Caimare Chico: 14.34 ind/m 2 ; Cano Sagua: 12.88 ind/m 2 ). Ambas especies exhibieron un patron similar en lo que respecta a la fluctuacion mensual de la abundancia, alta abundancia en el periodo de sequia (Diciembre - Abril) y baja abundancia en el periodo de lluvia (Mayo - Noviembre). El analisis de varianza simple arrojo una correlacion altamente significativa de la abundancia mensual de D. striatus (r - 0.821); df = 51.98; p < 0.000) y T. mactroides (r = 0.834); df = 57.17; p < 0.000) entre las playas. Esta correlacion sugiere bajos niveles de competencia interespecifica entre las especies y que probablemente ambas especies responden a estimulos ambientales similares.
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Echinoderms are a major group of marine invertebrates that often play integral roles within the marine ecosystem. Studies about their occurrence, abundance, and distribution in Venezuela are focused in the central-eastern coasts; hence... more
Echinoderms are a major group of marine invertebrates that often play integral roles within the marine ecosystem. Studies about their occurrence, abundance, and distribution in Venezuela are focused in the central-eastern coasts; hence the aim of this study is to describe the echinoderm community in the north-western coast of the Gulf of Venezuela. Samples were collected from three sites in the Venezuelan Guajira Peninsula (Castilletes, Porshoure, and Kazuzain) where patchy coral reefs and seagrass meadows are abundant. According to the substrate, two methods were performed using quantitative (1 m² quadrates), and qualitative free-diving observations. All organisms were counted and identified to the lowest possible taxonomic level; finally, diversity (Shannon diversity index), richness (number of species), and dominance in the different sampled substrates were recorded. The updated list of echinoderms of the Gulf of Venezuela reported in this research, includes 20 genera, 15 familie...
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RESUMEN El 27 de Febrero de 1997, el buque tanque griego Nissos Amorgos liberó 25.000 barriles de petróleo en el canal de navegación del Lago de Maracaibo, Venezuela. El petróleo liberado se dirigió hacia la costa de la playa Caimare... more
RESUMEN El 27 de Febrero de 1997, el buque tanque griego Nissos Amorgos liberó 25.000 barriles de petróleo en el canal de navegación del Lago de Maracaibo, Venezuela. El petróleo liberado se dirigió hacia la costa de la playa Caimare Chico donde llegaron 14.000 barriles de petróleo. Debido a las corrientes costeras y al viento, el petróleo se dispersó hacia el Noroeste cubriendo 48 Km de costas arenosas de alta energía, hasta la playa Caño Sagua. Debido a que se disponían de estudios de línea base acerca de la biodiversidad de invertebrados macrobentónicos de estas playas, se pudo hacer una estimación de la mortalidad que causó este derrame. Se utilizó el método SCAT para determinar la cobertura de petróleo y estimar la cantidad de invertebrados aniquilados. Los resultados indicaron que 7.580.000 macroinvertebrados murieron, eliminado al menos a 28 especies en Caño Sagua y 23 especies en Caimare Chico. Las almejas comerciales, Tivela mactroides (guacuco) y Donax striatus (chipichipi...
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The marine clam, Tivela mactroides, from Caño Sagua beach, Venezuela, was spawned and reared under laboratory conditions to monitor its early development. Spawning was spontaneous but in some cases it had to be induced by the additon of... more
The marine clam, Tivela mactroides, from Caño Sagua beach, Venezuela, was spawned and reared under laboratory conditions to monitor its early development. Spawning was spontaneous but in some cases it had to be induced by the additon of eggs and sperm. After fertilization, the embryonic development occurred at 5 hr approximately. Trochophore larvae were observed between eight and ten hours later. Straight-hinged veliger stage appeared 15 hr after fertilization. Transition from veliger stage to the umbo stage occurred about eight days after fertilization. Pediveliger stage was observed 22 days after fertilization. Metamorphosis of T. mactroides was not successful under our laboratory conditions; probably the bacterial contamination and subsequent mortalities were important factors constraining the final phase of the larval cycle. However, in a few cases young individuals were observed. We suspect that this was due to unfavorable conditions (e.g.: bacterial contamination, unsuitable f...
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The consumption of shellfish has been associated with microbial infections even in cases where shellfish complied with the current regulation, which is based on bacterial analysis. Depuration pro- cesses try to eliminate microorganisms... more
The consumption of shellfish has been associated with microbial infections even in cases where shellfish complied with the current regulation, which is based on bacterial analysis. Depuration pro- cesses try to eliminate microorganisms using seawater to allow living, filter-feeding shellfish to naturally purge themselves from agents they accumulated from the environment. In this study, depuration rates of potential indicators were
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... AND HÉCTOR J. SEVEREYN ... from fine to very fine sand grains (75425 μm), and dead clam shell (Donax striatus) remains (Rodríguez 1973, Delgado 1997 ... We sampled benthic bivalves monthly, from December 1995 to August 1996, during... more
... AND HÉCTOR J. SEVEREYN ... from fine to very fine sand grains (75425 μm), and dead clam shell (Donax striatus) remains (Rodríguez 1973, Delgado 1997 ... We sampled benthic bivalves monthly, from December 1995 to August 1996, during both rainy and dry seasons, using a ...
... 1 juvenil; [MBLUZ O1019); Man-glar La Rosita, Santa Cruz de Mara. Edo. Zulia, Venezuela; Octubre 1994; cois. José Delgado y Antonio Godoy. 8 machos y 12 juveniles: (MBLUZ 01020); Manglar La Ro-sita. Santa Cruz de Mara, Edo. ...
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... mangrove formations and on artificial wood panels under natural conditions, studies were perfarmed in the mangrove swarnp of Ana María Campos ... Los miembros de la familiaTeredinidae constituyen un grupo especializado de mo-lusco~... more
... mangrove formations and on artificial wood panels under natural conditions, studies were perfarmed in the mangrove swarnp of Ana María Campos ... Los miembros de la familiaTeredinidae constituyen un grupo especializado de mo-lusco~ bivalvos que perforan la riiadera. ...
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... Esto puede deberse a las mane-ras particulares en que reciben los aportes de materia orgánica cada una de ... aepynota Odostomia astricta Odostomia barkleyensis Odostomia excolpa Odostomia pocahontase Odostomia seminuda Odostomia... more
... Esto puede deberse a las mane-ras particulares en que reciben los aportes de materia orgánica cada una de ... aepynota Odostomia astricta Odostomia barkleyensis Odostomia excolpa Odostomia pocahontase Odostomia seminuda Odostomia laevigata Olivella floraria Olivella ...
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Con la finalidad de conocer el número cromosómico de la almeja estuarina Polymesoda so-lida, se llevó a cabo un estudio citogenético utilizando la técnica de secado al aire para la prepa-ración de los frotis. Se emplearon dos soluciones... more
Con la finalidad de conocer el número cromosómico de la almeja estuarina Polymesoda so-lida, se llevó a cabo un estudio citogenético utilizando la técnica de secado al aire para la prepa-ración de los frotis. Se emplearon dos soluciones hipotónicas diferentes (KCl y ...
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... Al personal del Laboratorio de Sistemá-tica de Invertebrados Acuáticos de la Uni-versidad del Zulia, por la colaboración pres-tada, a Alvaro Carrasquel por el tipeo del manuscrito y su incondicional apoyo, a An-tonio Olivares por su... more
... Al personal del Laboratorio de Sistemá-tica de Invertebrados Acuáticos de la Uni-versidad del Zulia, por la colaboración pres-tada, a Alvaro Carrasquel por el tipeo del manuscrito y su incondicional apoyo, a An-tonio Olivares por su ayuda en la limpieza de las muestras y ...
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... Mario L. Nava1, Héctor J. Severeyn1* y Yajaira García de Severeyn2 1Laboratorio de Sistemática de Invertebrados Acuáticos. ... Figura 4. A) Yoldia pelprotracta, B) Donax tumidus, C) Semele nuculoides, D) Lepton lepidum, E) Strigilla... more
... Mario L. Nava1, Héctor J. Severeyn1* y Yajaira García de Severeyn2 1Laboratorio de Sistemática de Invertebrados Acuáticos. ... Figura 4. A) Yoldia pelprotracta, B) Donax tumidus, C) Semele nuculoides, D) Lepton lepidum, E) Strigilla mirabilis, F)Bentharca sagrinata, G ...
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The estuarine clam, Polymesoda solida (Philippi, 1846), from Lake Maracaibo, Venezuela, was spawned and reared under laboratory conditions to monitor its early development. Spawning was induced via salinity changes and serotonin... more
The estuarine clam, Polymesoda solida (Philippi, 1846), from Lake Maracaibo, Venezuela, was spawned and reared under laboratory conditions to monitor its early development. Spawning was induced via salinity changes and serotonin injections. Serotonin injections ...
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The marine clam, Tivela mactroides, from Caño Sagua beach, Venezuela, was spawned and reared under laboratory conditions to monitor its early development. Spawning was spontaneous but in some cases it had to be induced by the additon of... more
The marine clam, Tivela mactroides, from Caño Sagua beach, Venezuela, was spawned and reared under laboratory conditions to monitor its early development. Spawning was spontaneous but in some cases it had to be induced by the additon of eggs and sperm. After fertilization, the embryonic development occurred at 5 hr approximately. Trochophore larvae were observed between eight and ten hours later. Straight-hinged veliger stage appeared 15 hr after fertilization. Transition from veliger stage to the umbo stage occurred about eight days after fertilization. Pediveliger stage was observed 22 days after fertilization. Metamorphosis of T. mactroides was not successful under our laboratory conditions; probably the bacterial contamination and subsequent mortalities were important factors constraining the final phase of the larval cycle. However, in a few cases young individuals were observed. We suspect that this was due to unfavorable conditions (e.g.: bacterial contamination, unsuitable food availability, etc.) and the broad variation in developmental times, suggesting that these stages might be particularly sensitive to environmental changes. These results may not necessarily reflect what happens under natural conditions.
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... AND HÉCTOR J. SEVEREYN ... from fine to very fine sand grains (75425 μm), and dead clam shell (Donax striatus) remains (Rodríguez 1973, Delgado 1997 ... We sampled benthic bivalves monthly, from December 1995 to August 1996, during... more
... AND HÉCTOR J. SEVEREYN ... from fine to very fine sand grains (75425 μm), and dead clam shell (Donax striatus) remains (Rodríguez 1973, Delgado 1997 ... We sampled benthic bivalves monthly, from December 1995 to August 1996, during both rainy and dry seasons, using a ...
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... Mario L. Nava1, Héctor J. Severeyn1* y Yajaira García de Severeyn2 1Laboratorio de Sistemática de Invertebrados Acuáticos. ... Figura 4. A) Yoldia pelprotracta, B) Donax tumidus, C) Semele nuculoides, D) Lepton lepidum, E) Strigilla... more
... Mario L. Nava1, Héctor J. Severeyn1* y Yajaira García de Severeyn2 1Laboratorio de Sistemática de Invertebrados Acuáticos. ... Figura 4. A) Yoldia pelprotracta, B) Donax tumidus, C) Semele nuculoides, D) Lepton lepidum, E) Strigilla mirabilis, F)Bentharca sagrinata, G ...
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... Juan de la Cruz Pa rra Me di na, Ya jai ra Gar cía de Se ve reyn*, Anngy Fe rrer y Héc tor Se ve reyn La bo ra to rio de Cul ti vo de In ver te bra dos Acuá ti cos, De par ta men to de Bio lo gía, Fa cul tad Ex pe ri men tal de Cien... more
... Juan de la Cruz Pa rra Me di na, Ya jai ra Gar cía de Se ve reyn*, Anngy Fe rrer y Héc tor Se ve reyn La bo ra to rio de Cul ti vo de In ver te bra dos Acuá ti cos, De par ta men to de Bio lo gía, Fa cul tad Ex pe ri men tal de Cien cias, Uni ver si dad del Zu lia. ...
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The presence of a microgastropod identified as Potamopyrgus sp. was detected previously in the Maracaibo System; nevertheless, a detailed morphological analysis identified this snail in other genera. The objective of this work is to... more
The presence of a microgastropod identified as Potamopyrgus sp. was detected previously in the Maracaibo System; nevertheless, a detailed morphological analysis identified this snail in other genera. The objective of this work is to update the distribution and taxonomy of Pyrgophorus platyrachis in the Maracaibo System, Venezuela in samples obtained between 2001 and 2009. The presence of hundreds of individuals of P. platyrachis were observed in the estuary, indeed in the localities of the Gran Eneal lagoon (4 111 snails), Peonías lagoon (229 snails), Punta Capitán Chico (758 snails), San Francisco (2 517 snails), Curarire (240 snails), Apon River mouth (173 snails), Ojeda City (240 snails), Bachaquero (128 snails) and Tomoporo de Agua (385 snails). We performed a taxonomical analysis, and emphasized in ecological aspects, such as the distribution of the species and habitat features, as near vegetation and type of associated sediment. We found three morphotypes of the species, one smooth, another with spiral striations and the other with spines. Smooth morphotype was exclusive of the Gran Eneal lagoon, Peonías lagoon, Punta Capitan Chico and Apon River mouth localities, whereas the other two morphotypes were found together in the remaining localities. According to our detailed anatomical and taxonomical analysis we propose a synonymy between P. platyrachis and the other species described like Pyrgophorus parvulus and Pyrgophorus spinosus.