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Page 1. Bull Environ, Contam. Toxicol. (1993) 50:659--664 9 1993 Springer-Verlag New York Inc. i Environ.rner~..al Effect of Detergent on the Response to Temperature and Growth of Grass Carp, Ctenopharyngodon iclella Guillermina Alcaraz,... more
Page 1. Bull Environ, Contam. Toxicol. (1993) 50:659--664 9 1993 Springer-Verlag New York Inc. i Environ.rner~..al Effect of Detergent on the Response to Temperature and Growth of Grass Carp, Ctenopharyngodon iclella Guillermina Alcaraz, Carlos Rosas, and Sonia Espina ...
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En los juveniles de la carpa herbívora aclimatados a 24, 29 y 32OC, se midió la toxicidad aguda del nitrito; para observar el efecto de los iones nitrito y cloruro se utilizó agua destilada. Asimismo, mediante ensayos agudos a corto plazo... more
En los juveniles de la carpa herbívora aclimatados a 24, 29 y 32OC, se midió la toxicidad aguda del nitrito; para observar el efecto de los iones nitrito y cloruro se utilizó agua destilada. Asimismo, mediante ensayos agudos a corto plazo se determinó el efecto tóxico del nitrito. Posteriormente se evaluó el efecto combinado de la temperatura y cloruro en peces expuestos por 48 h a las CL50, CL70 y CL90 del nitrito. Tanto la temperatura como el cloruro tuvieron un efecto protector ante la toxicidad del nitrito. Los niveles de los estimadores de esta acción del nitrito aumentaron tanto en 29 como en 32OC en comparación con 24OC, siendo mayor en la primera. La protección del cloruro se manifesto en peces expuestos al nitrito a la concentración donde se registró la CL50 y menos evidente en las CL70 y CL90. Se calculó la ecuación polinomial, que engloba a las variables investigadas y predice que al aumentar la razón iónica (nitrito/ cloruro) se incrementa la mortalidad siendo ésta menor...
Stress indices in different biological organization levels are analyzed as tools in ecotoxicological studies. Individual stress indices of high organization levels are proposed to obtain a confident knowledge of the damages or... more
Stress indices in different biological organization levels are analyzed as tools in ecotoxicological studies. Individual stress indices of high organization levels are proposed to obtain a confident knowledge of the damages or disadvantages caused by pollutants on individual organisms, under the assumption that any disadvantage (caused by stress agents) on individuals provide a confident evidence of a detrimental condition of the population. Particularly, relevant individual animal responses related with changes of the use of environmental resources, alterations of avoidance responses, shifts of biotic preferences, and decrease on functional capacity and performance are proposed as useful indices in ecotoxicological studies.
RESUMEN RESUMEN En los últimos decenios, la actividad antropogénica ha transformado la dinámica y la estructura de los ecosistemas. Gran parte de la superficie de la tierra, la totalidad de los cuerpos de agua continentales y los océanos... more
RESUMEN RESUMEN En los últimos decenios, la actividad antropogénica ha transformado la dinámica y la estructura de los ecosistemas. Gran parte de la superficie de la tierra, la totalidad de los cuerpos de agua continentales y los océanos han sufrido modificaciones por la actividad del hombre. De esta forma, el incremento en la cantidad y diversidad de los productos químicos descargados en los ecosistemas a partir de los cincuenta y sesenta, fomentaron el interés de los científicos en el estudio de los efectos de la descarga de contaminantes en los sistemas naturales, y en particular la ecotoxicología fue la disciplina que enfrentó el desafío de reconocer, entender e intentar predecir las consecuencias causadas por dichos contaminantes en el ambiente Esta disciplina.
The toxic effect of waterborne nitrite on the energy budget of juvenile grass carp was measured. In grass carp exposed to nitrite, the ingestion rates were unaffected, whereas assimilation efficiency and assimilation were reduced. The... more
The toxic effect of waterborne nitrite on the energy budget of juvenile grass carp was measured. In grass carp exposed to nitrite, the ingestion rates were unaffected, whereas assimilation efficiency and assimilation were reduced. The respiratory rate decreased with ...
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Hermit crabs respond to predators by hiding in their shells. However, retraction may cause the crab to lose hold of the rock and fall through the water column, and the crab may land with the shell aperture in a different orientation. When... more
Hermit crabs respond to predators by hiding in their shells. However, retraction may cause the crab to lose hold of the rock and fall through the water column, and the crab may land with the shell aperture in a different orientation. When the shell is aperture down, hermit crabs return to activity by moving their bodies forward and placing their legs on the ground. In contrast, when the shell is aperture up, crabs need to perform a righting maneuver by extending part of their bodies out of the shell, which makes them more vulnerable to predation. The main goal of this study was to examine the hiding time of the hermit crab Calcinus californiensis Bouvier, 1898 in different shell species under these two different situations to better understand the conflict between the cost of staying in hiding and the risk of predation. The study was conducted in rocky tide pools using seven different shell types that reflect different predator protection and resource value to the crab (based on pre...
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... OF NITRITE ON THE RESPIRATORY RESPONSE OF GRASS CARP CTENOPHARYNGODON IDELLA (VAL.) WITH RELATION TO CHLORIDE SONIA ESPINA and ... JR and Carmichael GJ (1986) Acute toxicity of ammonia, nitrite, and nitrate to the Guadalupe Bass,... more
... OF NITRITE ON THE RESPIRATORY RESPONSE OF GRASS CARP CTENOPHARYNGODON IDELLA (VAL.) WITH RELATION TO CHLORIDE SONIA ESPINA and ... JR and Carmichael GJ (1986) Acute toxicity of ammonia, nitrite, and nitrate to the Guadalupe Bass, Micropterus ...
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Research Interests: Zoology, Crustacea, Ecology, Salinity, Estuaries, and 3 moreParasite, Respiration, and Oxygen Consumption
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... ADRIANA MUHLIA-ALMAZA´ Na, ARTURO MUHLIA-MELOa and GUILLERMINA ALCARAZb,* ... The faster the fish grow, the lower the risk of been a potential prey (Werner and Gilliam, 1984), so reduced growth rates under the environmental condition... more
... ADRIANA MUHLIA-ALMAZA´ Na, ARTURO MUHLIA-MELOa and GUILLERMINA ALCARAZb,* ... The faster the fish grow, the lower the risk of been a potential prey (Werner and Gilliam, 1984), so reduced growth rates under the environmental condition prevailing in the Ensenada ...
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This study tested the effect of sustained swimming on growth, ingestion rate, and morphology of juvenile montezumae swordtails (Xiphophorus montezumae). Because montezumae swordtails inhabit running freshwater systems, it was expected... more
This study tested the effect of sustained swimming on growth, ingestion rate, and morphology of juvenile montezumae swordtails (Xiphophorus montezumae). Because montezumae swordtails inhabit running freshwater systems, it was expected that moderate exercise would increase feeding and growth rates, promoting also the hydrodynamic form of the fish. Experimental groups were subjected to different levels of sustained exercise by being forced
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ABSTRACT Mechanisms that favour the co-occurrence of morphologically and ecologically similar species in South America are potentially relevant, because two or more species often occur in sympatry. In the present study, we investigated... more
ABSTRACT Mechanisms that favour the co-occurrence of morphologically and ecologically similar species in South America are potentially relevant, because two or more species often occur in sympatry. In the present study, we investigated possible mechanisms of resource partitioning between two sympatric species of foxes, the crab-eating fox Cerdocyon thous and the pampas fox Pseudalopex gymnocercus, in the National Park of Aparados da Serra in southern Brazil (29°10′S, 50°05′W). We considered three main niche dimensions – habitat, diet and time – and evaluated the overlap between the two species in these dimensions. We conducted the study from June 2000 to October 2001 in an area composed of open grasslands and Araucaria forests. We studied the foxes by using a combination of scat analysis and direct observation. A comparison of their diet indicated that it was very similar for both species in all seasons (Pianka's indexes ranging from 0.920 to 0.957). The most common food item for both species of foxes was rodents, followed by coleopterans, birds and plant remains (seeds and fruits). As expected by the niche-complementarity hypothesis, we detected differences along other niche axes. Pseudalopex gymnocercus seemed to occur only in open areas, including grasslands and dirt roads, whereas C. thous was more generalist in habitat use, occurring both inside and at the edge of forests. However, both fox species were common in grassland habitats, where they might compete for resources. The differences were more marked for activity time, with the crab-eating fox being significantly more nocturnal (circular mean of time of sighting=23:39 h, se=56 min) than the pampas fox (circular mean=19:56 h, se=64 min; Watson's F=6.06, P=0.02). We suggest that the larger C. thous could be limiting the activity of P. gymnocercus by interference competition.
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... This study tested the hypothesis that in Montezuma swordtail Xiphophorus montezumae, bearers of longer swords would face higher costs in terms of swimming speed than males with shorter swords, as a result of differences in total body... more
... This study tested the hypothesis that in Montezuma swordtail Xiphophorus montezumae, bearers of longer swords would face higher costs in terms of swimming speed than males with shorter swords, as a result of differences in total body length when natural swords were ...
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ABSTRACT The standard metabolic rate (SMR) is a central aspect in bioenergetics closely related to fitness, where consistent differences in the SMR may account for differences in an individual's performance. The SMR can be a... more
ABSTRACT The standard metabolic rate (SMR) is a central aspect in bioenergetics closely related to fitness, where consistent differences in the SMR may account for differences in an individual's performance. The SMR can be a plastic trait, where the metabolic depression can be advantageous under unfavourable conditions. The SMR of the hermit crab Calcinus californiensis occupying intact and broken shells in the wild were com-pared. Subsequently, a shell-swapping experiment and repeated measures test of the SMR of crabs occupy-ing both types of shells were made to test if differences in the SMR were a consequence of the shell occupied (plasticity) or a result of an intrinsic variation between individuals (consistency). Crabs occupying broken shells had a lower metabolism than those in intact shells. The gradual recovery of the SMR of the crabs swapped to broken shells to similar metabolic levels of those of crabs tested in intact shells suggests that though the use of a broken shell can be disadvantageous in the wild, broken shells might produce a more benign situation under laboratory conditions. The depression of the SMR may act as an adaptive response to cope with the disadvantages caused by broken shells in a challenging environment. The SMR showed individual consistency, suggesting that it may play an important role as an adaptive trait.
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ABSTRACT The osmoregulatory response and oxygen consumption rate of the strictly freshwater prawn, Macrobrachium tuxtlaense were measured under different salinity conditions. The goal of these experiments was to explore how the adaptive... more
ABSTRACT The osmoregulatory response and oxygen consumption rate of the strictly freshwater prawn, Macrobrachium tuxtlaense were measured under different salinity conditions. The goal of these experiments was to explore how the adaptive process to the freshwater environment has proceeded from a metabolic point of view in a hololimnetic species. Nine to 11 intermoult prawns were exposed to salinities of 0, 5, 10, 15, 20, 25, and 30‰, respectively. Once oxygen consumption was measured, haemolymph osmolality was determined by sampling of 20 μl aliquots. The results indicate that the oxygen consumption rate decreased significantly with increasing salinity. The respiration of prawns exposed to 5‰ salinity was 56% higher than the rate of those exposed to 20 and 25‰. The prawns behaved as strong hyperregulators in low salinity; at higher salinities, the haemolymph osmolality showed a sharp increase, although it remained hyperosmotic to the medium; the isosmotic point was reached at 700 mOsm. Based on our results, M. tuxtlaense in general shows a pattern similar to that of other hololimnetic species, but with some unique aspects, such as a high isosmotic point and an inability to survive at salinities above 28‰. This suggests an advanced degree of adaptation to the freshwater environment.
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The preference of the hermit crab Calcinus californiensis Bouvier, 1898 among six shell species and different shell sizes was evaluated in the presence of the swimming crab Arenaeus mexicanus (Gerstaecker, 1856), a natural predator of... more
The preference of the hermit crab Calcinus californiensis Bouvier, 1898 among six shell species and different shell sizes was evaluated in the presence of the swimming crab Arenaeus mexicanus (Gerstaecker, 1856), a natural predator of this species. In a second experiment, the survival benefit of the shell choice made under predation threat was examined by exposing hermit crabs occupying three different shell species (including the most and least preferred shells of two fits) to a free swimming crab predator. The preference for shell species was similar in the absence and presence of the predator threat, although the hermit crabs choose larger shells (loose) when exposed to the predator compared with the ones chosen in its absence. The predatory experiment showed a higher survival chance for the hermit crabs occupying loose shells of the preferred shell species (Cantharus sanguinolentus (Duclos, 1833)). The results of this study show that the hermit crab C. californiensis is able to ...
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Revista Internacional de Contaminación Ambiental Revista Internacional de Contaminación Ambiental Universidad Nacional Autónoma de México rvp@atmosfera.unam.mx ISSN (Versión impresa): 0188-4999 MÉXICO 1993 Guillermina Alcaraz / Sonia... more
Revista Internacional de Contaminación Ambiental Revista Internacional de Contaminación Ambiental Universidad Nacional Autónoma de México rvp@atmosfera.unam.mx ISSN (Versión impresa): 0188-4999 MÉXICO 1993 Guillermina Alcaraz / Sonia Espina EFECTO DE LA ...
... Cox, 1974. DK Cox, Effect of three heating rates on the critical thermal maximum of bluegill. In: Thermal EcologyJ.W. Gibbon and RR Sharitz, Editors, Atomic Energy Commission Symposium Series (Conf. 730505) (1974), pp. 158–163.... more
... Cox, 1974. DK Cox, Effect of three heating rates on the critical thermal maximum of bluegill. In: Thermal EcologyJ.W. Gibbon and RR Sharitz, Editors, Atomic Energy Commission Symposium Series (Conf. 730505) (1974), pp. 158–163. Gaxiola, 1994. ...
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Juvenile growth rate is an important life-history trait that affects the size at maturity, and may influence the development of sexual ornamentation. The sword of several species of the genus Xiphophorus (Teleostei: Poeciliidae) is an... more
Juvenile growth rate is an important life-history trait that affects the size at maturity, and may influence the development of sexual ornamentation. The sword of several species of the genus Xiphophorus (Teleostei: Poeciliidae) is an elaborate secondary sexual trait that confers an advantage in terms of sexual selection, counterbalanced by locomotive and predatory costs. This study assesses differences in male juvenile growth, age, and size at maturation and their relationship with maximum body size and sword elongation in ...
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1. 1. The effect of eyestalk ablation on preadults of Callinectes similis exposed to a constant salinity (30%.) and to simulated tidal changes in salinity (30-11 to 30%.) were measured. ... 2. 2. In constant salinity, crabs showed a... more
1. 1. The effect of eyestalk ablation on preadults of Callinectes similis exposed to a constant salinity (30%.) and to simulated tidal changes in salinity (30-11 to 30%.) were measured. ... 2. 2. In constant salinity, crabs showed a persistent respiratory rhythm, with a maximum oxygen ...