Gerardo Leyte - Academia.edu (original) (raw)
Papers by Gerardo Leyte
Diversity
The distinction between shallow coral reefs and mesophotic coral ecosystems (MCEs) has not been f... more The distinction between shallow coral reefs and mesophotic coral ecosystems (MCEs) has not been fully clarified yet. The original definition of MCEs, by depths of 30–150 m, fixes their bathymetrical limits and fails to accommodate environmental and biological variation. Recent studies have indicated that water transparency and light availability may explain why MCEs do not occur at fixed depths but vary among localities. This study aimed to evaluate the presence and distribution of MCEs, along the central coast of Oaxaca, through optical depths and the associated benthic community. Using MODIS-Aqua satellite data (Kd490), we estimated the mesophotic optical depths monthly (z10%, z1%, z0.1%), over the last four years. In addition, to characterize benthic community structure, we conducted underwater photo quadrat surveys at two locations on the southern Mexican Pacific coast from 10 to 55 m depth. Significant differences between depths and locations were found in benthic communities. ...
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CICIMAR Oceánides, 2006
En el arrecife de La Entrega se realizaron muestreos bimestrales de Octubre de 2002 a Agosto de 2... more En el arrecife de La Entrega se realizaron muestreos bimestrales de Octubre de 2002 a Agosto de 2003. Con el material recolectado, se caracterizó a la comunidad de moluscos asociados al coral Pocillopora damicornis, para comparar su es tructura con la que existía en 1994-1995. Se encontró que la diversidad no ha tenido cambios estadísticamente significativos, sin embargo, si se han presentado cambios en la abundancia de las especies dominantes, entre las que destaca el incremento de organismos del género Lithophaga y Quoyula madreporarum, y la disminución de Muricopsis zeteki y Cantharus spp., especies estrechamente ligadas a los procesos en los arrecifes, como la bioerosión en los corales. Estas especies han encontrado, en la frágil estructura del arrecife, condiciones óptimas para su colonización y desarrollo, que en una escala temporal más amplia podrían causar desequilibrio ecológico, como ha sucedido en otros arrecifes alrededor del mundo. Diversity and abundance variation of d...
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Marine Biology, 2011
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CICIMAR Oceánides, 2005
Bimonthly samples of sea urchins fauna inhabiting the La Entrega Reef, Oaxaca, Mexico, were obtai... more Bimonthly samples of sea urchins fauna inhabiting the La Entrega Reef, Oaxaca, Mexico, were obtained from October 2002 to August 2003. The reef area was divided in two sampling zones, corresponding to shallow (0-6 m) and deep (6-12 m) water. Six transects of 50 m length by 1 m wide were sampled in each zone. Greatest annual density corresponded to Diadema mexicanum (5.96 ± 0.85 ind/m2), followed by Eucidaris thouarsii (0.46 ± 0.14 ind/m2); Echinometra vanbrunti and Toxopneustes roseuspresented low densities (0.03 ± 0.01 indv/m2 and 0.02 ± 0.01 ind/m2, respectively). Density of the four populations varied considerably and higher densities were observed in the deep zone. Total abundance of sea urchins (shallow and deep samples) did not vary significantly over time. Abundance per depth range, however, was different over time for all species except for E. thouarsii. In December densities of D. mexicanum and E. thouarsii decreased in the deep zone and increased in the shallow zone, due t...
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Zootaxa, 2010
Although fish are one of the most abundant, conspicuous and structurally important inhabitants of... more Although fish are one of the most abundant, conspicuous and structurally important inhabitants of reef systems, the group has remained largely ignored from biodiversity accounts on the Oaxaca reef track. Reef icthyofauna composition at 10 sites between Mazunte and Isla Montosa was gathered through stationary visual census techniques during 19982008. A total of 112 species belonging to 81 genera, 40 families and 11 orders were recorded. Species richness of the study area is higher than similar reef communities in the Mexican Pacific. Thirty species represent new records for the study area, and some discrepancies were found between local (this study) and regional accounts. Our data suggest that species composition in the area is still incomplete.
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Veterinaria Mexico, 2010
Con el fin de evaluar la etapa reproductiva en hembras de iguana verde ( Iguana iguana ) mantenid... more Con el fin de evaluar la etapa reproductiva en hembras de iguana verde ( Iguana iguana ) mantenidas en cautiverio, en Oaxaca, Mexico, se utilizaron 137 hembras, durante seis anos. Se ofrecio alimento concentrado, plantas de frijolillo ( Desmodium infortum ) y flor de tulipan ( Tulipa gesneriana ). Las hembras fueron identificadas y alojadas en jaulas de 30 m 2 ; se observaron y registraron las actividades reproductivas de proestro, estro y gestacion. En la etapa de eclosion, se midieron las variables de los huevos y se incubaron en cajas de unicel con humedad relativa de 65% a 85% y temperatura de 28° a 34°C; las crias se midieron despues de la eclosion. Para el analisis de resultados se utilizo estadistica descriptiva y analisis de correlacion canonica con el paquete estadistico SAS. En el inicio del periodo reproductivo, las hembras pesaron 975.9 ± 405 g y midieron de longitud hocico-cloaca 27.9 ± 3.4 cm, la masa relativa de nidada fue de 36.3 ± 7.1%, con tamano de 23.5 huevos, de...
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El presente trabajo tuvo como objetivo obtener un modelo matematico de crecimiento del peso con r... more El presente trabajo tuvo como objetivo obtener un modelo matematico de crecimiento del peso con respecto a la longitud hocico-cloaca en iguana negra Ctenosaura pectinata mediante la aplicacion del metodo de regresion polinomial. Se utilizaron 2,030 registros de iguanas del Centro de Conservacion y Reproduccion de Iguanas de la Universidad del Mar, Oaxaca, con edades de cero a nueve anos. Los animales se pesaron (g) y se midio su longitud hocico-cloaca (cm) a diferentes intervalos de tiempo. Con los datos promedio, se realizo una regresion polinomial de tercer grado que genero el modelo matematico. El coeficiente de correlacion fue de 0.997. Se calculo el error estandar de la aproximacion, posteriormente se derivo la ecuacion definida en el modelo para encontrar la velocidad con que el animal aumenta su peso respecto a la longitud hocico-cloaca. Al derivar nuevamente la ecuacion e igualar a cero, se obtuvo el punto de inflexion del modelo. La longitud hocico-cloaca donde se presento ...
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Bulletin of Marine Science, 2001
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... quizás debido a que La tienen registros de 38 especies, aunque en Entrega se ha visto afectad... more ... quizás debido a que La tienen registros de 38 especies, aunque en Entrega se ha visto afectada por los muestreos realizados de 1986 a 1993 por constantes dragados que se han realizado en Cintra-Buenrostro et al. ... 24. Landa-Jaime, V., E. Michel-Morfín, J. Arciniega-Flores ...
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Revista De Biologia Tropical, 1997
Numerous pocilloporid coral reef occur along lhe 26 km coastline of Huatulco, Gulf of Tehuantepec... more Numerous pocilloporid coral reef occur along lhe 26 km coastline of Huatulco, Gulf of Tehuantepec. Mexico. Twelve species of zooxanthellate corals belonging to four genera (Pocillopora, Pavona, Porites, Psammocora) are presen! in this area with three species of pociHoporid corais Jarge!y responsible for red framework construction. Seventeen fringing reefs, with mean depths ranging from 2 to 14 rn, displayed maximum, horizontal framework dimensions ranging from 58 x 85 m (width x lcngth) lO 283 x 355 m. Recf topographic pro files suggest that vertical framework buildups range from about 1 to 5 m. Most reef developrnent occurs in bays or along protected shores with hillocky Ol' gently sloping pocillopodd frameworks. At sorne exposed sites, 2-3 rn high surge channels dissect seaward-facing reef slopes. Sudden cooling of nearshore waters, from 24°C lo 20°C, was detected al lhe reef base (8 m) on a Huatulco reef in February 1996, during the usual upwelling season (November-April) in ...
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Bulletin of Marine Science, 2001
Reefs of the Huatulco area, southern Mexico, were exposed to an unprecedented sequence of three m... more Reefs of the Huatulco area, southern Mexico, were exposed to an unprecedented sequence of three major storms (Olaf, Pauline, and Rick) over a 2-mo period (September-November 1997). The prior establishment of monitoring transects, as well as the timing of our surveys just 1 mo after the passage of Hurricane Rick, provided an unique opportunity to document storm impacts on these recently described reef communities of the eastern Pacific. Considering the lack of prior hurricane damage to these reefs, the dominance of branching pocilloporid corals, and the intensity and high frequency of the 1997 storms that affected the area, it was hypothesized that storm-generated damage patterns would be significant and consistent among the reefs of Huatulco. However, the damage patterns documented were limited in severity and variable in spatial distribution. Of the six reefs surveyed prior to the first storm in July-August 1997, only three showed significant decreases in live coral cover, whereas ...
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Science of The Total Environment
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Bulletin of Marine and Coastal Research
Knowledge of echinoderms from Zihuatanejo and Acapulco, Guerrero is currently limited to taxonomi... more Knowledge of echinoderms from Zihuatanejo and Acapulco, Guerrero is currently limited to taxonomic listings. This work attempts to characterize better the community of these organisms associated to coral reefs in this region using band transects of 50 m length by 1 m width. Two samplings were carried out in 2004, one in the rainy season and other in the dry season. Ten species, three Asteroidea, six Echinoidea and one Holothuroidea, were found. The mean values obtained for diversity in the 13 study sites (1.036 bits ind-1) are considered low when compared with the maximum possible diversity (3.322 bits ind-1), and this is likely due to the dominance of the black sea urchin Diadema mexicanum and the starsh Phataria unifascialis, with densities reported of 1.45±0.60 ind m-2 and 0.12±0.02 ind m-2, respectively. The highest diversity was associated with low tide, which is not different between localities. The spatial arrangement of the echinoderm species composition obtained by the mult...
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Coral Reefs
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Veterinaria Mexico Vol 41 No 004, Sep 14, 2011
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Bulletin of Marine Science Miami, Jun 30, 2001
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Revista De Biologia Tropical, 1997
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Pacific Science
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Diversity
The distinction between shallow coral reefs and mesophotic coral ecosystems (MCEs) has not been f... more The distinction between shallow coral reefs and mesophotic coral ecosystems (MCEs) has not been fully clarified yet. The original definition of MCEs, by depths of 30–150 m, fixes their bathymetrical limits and fails to accommodate environmental and biological variation. Recent studies have indicated that water transparency and light availability may explain why MCEs do not occur at fixed depths but vary among localities. This study aimed to evaluate the presence and distribution of MCEs, along the central coast of Oaxaca, through optical depths and the associated benthic community. Using MODIS-Aqua satellite data (Kd490), we estimated the mesophotic optical depths monthly (z10%, z1%, z0.1%), over the last four years. In addition, to characterize benthic community structure, we conducted underwater photo quadrat surveys at two locations on the southern Mexican Pacific coast from 10 to 55 m depth. Significant differences between depths and locations were found in benthic communities. ...
Bookmarks Related papers MentionsView impact
CICIMAR Oceánides, 2006
En el arrecife de La Entrega se realizaron muestreos bimestrales de Octubre de 2002 a Agosto de 2... more En el arrecife de La Entrega se realizaron muestreos bimestrales de Octubre de 2002 a Agosto de 2003. Con el material recolectado, se caracterizó a la comunidad de moluscos asociados al coral Pocillopora damicornis, para comparar su es tructura con la que existía en 1994-1995. Se encontró que la diversidad no ha tenido cambios estadísticamente significativos, sin embargo, si se han presentado cambios en la abundancia de las especies dominantes, entre las que destaca el incremento de organismos del género Lithophaga y Quoyula madreporarum, y la disminución de Muricopsis zeteki y Cantharus spp., especies estrechamente ligadas a los procesos en los arrecifes, como la bioerosión en los corales. Estas especies han encontrado, en la frágil estructura del arrecife, condiciones óptimas para su colonización y desarrollo, que en una escala temporal más amplia podrían causar desequilibrio ecológico, como ha sucedido en otros arrecifes alrededor del mundo. Diversity and abundance variation of d...
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Marine Biology, 2011
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CICIMAR Oceánides, 2005
Bimonthly samples of sea urchins fauna inhabiting the La Entrega Reef, Oaxaca, Mexico, were obtai... more Bimonthly samples of sea urchins fauna inhabiting the La Entrega Reef, Oaxaca, Mexico, were obtained from October 2002 to August 2003. The reef area was divided in two sampling zones, corresponding to shallow (0-6 m) and deep (6-12 m) water. Six transects of 50 m length by 1 m wide were sampled in each zone. Greatest annual density corresponded to Diadema mexicanum (5.96 ± 0.85 ind/m2), followed by Eucidaris thouarsii (0.46 ± 0.14 ind/m2); Echinometra vanbrunti and Toxopneustes roseuspresented low densities (0.03 ± 0.01 indv/m2 and 0.02 ± 0.01 ind/m2, respectively). Density of the four populations varied considerably and higher densities were observed in the deep zone. Total abundance of sea urchins (shallow and deep samples) did not vary significantly over time. Abundance per depth range, however, was different over time for all species except for E. thouarsii. In December densities of D. mexicanum and E. thouarsii decreased in the deep zone and increased in the shallow zone, due t...
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Zootaxa, 2010
Although fish are one of the most abundant, conspicuous and structurally important inhabitants of... more Although fish are one of the most abundant, conspicuous and structurally important inhabitants of reef systems, the group has remained largely ignored from biodiversity accounts on the Oaxaca reef track. Reef icthyofauna composition at 10 sites between Mazunte and Isla Montosa was gathered through stationary visual census techniques during 19982008. A total of 112 species belonging to 81 genera, 40 families and 11 orders were recorded. Species richness of the study area is higher than similar reef communities in the Mexican Pacific. Thirty species represent new records for the study area, and some discrepancies were found between local (this study) and regional accounts. Our data suggest that species composition in the area is still incomplete.
Bookmarks Related papers MentionsView impact
Veterinaria Mexico, 2010
Con el fin de evaluar la etapa reproductiva en hembras de iguana verde ( Iguana iguana ) mantenid... more Con el fin de evaluar la etapa reproductiva en hembras de iguana verde ( Iguana iguana ) mantenidas en cautiverio, en Oaxaca, Mexico, se utilizaron 137 hembras, durante seis anos. Se ofrecio alimento concentrado, plantas de frijolillo ( Desmodium infortum ) y flor de tulipan ( Tulipa gesneriana ). Las hembras fueron identificadas y alojadas en jaulas de 30 m 2 ; se observaron y registraron las actividades reproductivas de proestro, estro y gestacion. En la etapa de eclosion, se midieron las variables de los huevos y se incubaron en cajas de unicel con humedad relativa de 65% a 85% y temperatura de 28° a 34°C; las crias se midieron despues de la eclosion. Para el analisis de resultados se utilizo estadistica descriptiva y analisis de correlacion canonica con el paquete estadistico SAS. En el inicio del periodo reproductivo, las hembras pesaron 975.9 ± 405 g y midieron de longitud hocico-cloaca 27.9 ± 3.4 cm, la masa relativa de nidada fue de 36.3 ± 7.1%, con tamano de 23.5 huevos, de...
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El presente trabajo tuvo como objetivo obtener un modelo matematico de crecimiento del peso con r... more El presente trabajo tuvo como objetivo obtener un modelo matematico de crecimiento del peso con respecto a la longitud hocico-cloaca en iguana negra Ctenosaura pectinata mediante la aplicacion del metodo de regresion polinomial. Se utilizaron 2,030 registros de iguanas del Centro de Conservacion y Reproduccion de Iguanas de la Universidad del Mar, Oaxaca, con edades de cero a nueve anos. Los animales se pesaron (g) y se midio su longitud hocico-cloaca (cm) a diferentes intervalos de tiempo. Con los datos promedio, se realizo una regresion polinomial de tercer grado que genero el modelo matematico. El coeficiente de correlacion fue de 0.997. Se calculo el error estandar de la aproximacion, posteriormente se derivo la ecuacion definida en el modelo para encontrar la velocidad con que el animal aumenta su peso respecto a la longitud hocico-cloaca. Al derivar nuevamente la ecuacion e igualar a cero, se obtuvo el punto de inflexion del modelo. La longitud hocico-cloaca donde se presento ...
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Bulletin of Marine Science, 2001
RefDoc Bienvenue - Welcome. Refdoc est un service / is powered by. ...
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... quizás debido a que La tienen registros de 38 especies, aunque en Entrega se ha visto afectad... more ... quizás debido a que La tienen registros de 38 especies, aunque en Entrega se ha visto afectada por los muestreos realizados de 1986 a 1993 por constantes dragados que se han realizado en Cintra-Buenrostro et al. ... 24. Landa-Jaime, V., E. Michel-Morfín, J. Arciniega-Flores ...
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Revista De Biologia Tropical, 1997
Numerous pocilloporid coral reef occur along lhe 26 km coastline of Huatulco, Gulf of Tehuantepec... more Numerous pocilloporid coral reef occur along lhe 26 km coastline of Huatulco, Gulf of Tehuantepec. Mexico. Twelve species of zooxanthellate corals belonging to four genera (Pocillopora, Pavona, Porites, Psammocora) are presen! in this area with three species of pociHoporid corais Jarge!y responsible for red framework construction. Seventeen fringing reefs, with mean depths ranging from 2 to 14 rn, displayed maximum, horizontal framework dimensions ranging from 58 x 85 m (width x lcngth) lO 283 x 355 m. Recf topographic pro files suggest that vertical framework buildups range from about 1 to 5 m. Most reef developrnent occurs in bays or along protected shores with hillocky Ol' gently sloping pocillopodd frameworks. At sorne exposed sites, 2-3 rn high surge channels dissect seaward-facing reef slopes. Sudden cooling of nearshore waters, from 24°C lo 20°C, was detected al lhe reef base (8 m) on a Huatulco reef in February 1996, during the usual upwelling season (November-April) in ...
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Bulletin of Marine Science, 2001
Reefs of the Huatulco area, southern Mexico, were exposed to an unprecedented sequence of three m... more Reefs of the Huatulco area, southern Mexico, were exposed to an unprecedented sequence of three major storms (Olaf, Pauline, and Rick) over a 2-mo period (September-November 1997). The prior establishment of monitoring transects, as well as the timing of our surveys just 1 mo after the passage of Hurricane Rick, provided an unique opportunity to document storm impacts on these recently described reef communities of the eastern Pacific. Considering the lack of prior hurricane damage to these reefs, the dominance of branching pocilloporid corals, and the intensity and high frequency of the 1997 storms that affected the area, it was hypothesized that storm-generated damage patterns would be significant and consistent among the reefs of Huatulco. However, the damage patterns documented were limited in severity and variable in spatial distribution. Of the six reefs surveyed prior to the first storm in July-August 1997, only three showed significant decreases in live coral cover, whereas ...
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Science of The Total Environment
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Bulletin of Marine and Coastal Research
Knowledge of echinoderms from Zihuatanejo and Acapulco, Guerrero is currently limited to taxonomi... more Knowledge of echinoderms from Zihuatanejo and Acapulco, Guerrero is currently limited to taxonomic listings. This work attempts to characterize better the community of these organisms associated to coral reefs in this region using band transects of 50 m length by 1 m width. Two samplings were carried out in 2004, one in the rainy season and other in the dry season. Ten species, three Asteroidea, six Echinoidea and one Holothuroidea, were found. The mean values obtained for diversity in the 13 study sites (1.036 bits ind-1) are considered low when compared with the maximum possible diversity (3.322 bits ind-1), and this is likely due to the dominance of the black sea urchin Diadema mexicanum and the starsh Phataria unifascialis, with densities reported of 1.45±0.60 ind m-2 and 0.12±0.02 ind m-2, respectively. The highest diversity was associated with low tide, which is not different between localities. The spatial arrangement of the echinoderm species composition obtained by the mult...
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Coral Reefs
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Veterinaria Mexico Vol 41 No 004, Sep 14, 2011
Bookmarks Related papers MentionsView impact
Bulletin of Marine Science Miami, Jun 30, 2001
Bookmarks Related papers MentionsView impact
Revista De Biologia Tropical, 1997
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Pacific Science
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