Background: Studies of population biology are scarce in Mediterranean striped dolphins (Stenella ... more Background: Studies of population biology are scarce in Mediterranean striped dolphins (Stenella coeruleoalba) mostly because of the lack of samples. Until now, studies of physical maturity, growth, and development of the flipper bones were not available for this species in the Mediterranean.
Background: Studies of population biology are scarce in Mediterranean striped dolphins (Stenella ... more Background: Studies of population biology are scarce in Mediterranean striped dolphins (Stenella coeruleoalba) mostly because of the lack of samples. Until now, studies of physical maturity, growth, and development of the flipper bones were not available for this species in the Mediterranean.
The use of photo-identification and its reliability in capture-recapture studies of Mediterranean... more The use of photo-identification and its reliability in capture-recapture studies of Mediterranean monk seals were assessed using slides collected in the colony at Cap Blanc, western Sahara, from 1993 to 1996. Five tests indicated that researchers involved in photo-identification were proficient in matching slides of identified seals, consistent in classifying the side of the seal shown in slides and in assigning the morphological stage of the seal, and that changes of markings over a period of three years were insufficient to affect matching success. The certainty of identifying a seal was not dependent on the number of slides used but on distinctiveness of the markings and the quality of the slides taken. Capture-recapture abundance estimates were biased upwards when including poor quality slides. The exclusive use of excellent- and good quality slides provided the best estimates. The proportion of distinctive seals varied between morphological stages and was significantly lower in juveniles. When including the identification histories of juveniles, the heterogeneity of capture probabilities was higher. Therefore, abundance estimates were less biased when all juveniles were considered as non-distinctive seals. Reliable abundance estimates required a balance between duration of capture occasions and time interval between these.
The resolution of taxonomic classifications for delphinid cetaceans has been problematic, especia... more The resolution of taxonomic classifications for delphinid cetaceans has been problematic, especially for species in the genera Delphinus, Tursiops and Stenella. The frequent lack of correspondence between morphological and genetic differentiation in these species raises questions about the mechanisms responsible for their evolution. In this study we focus on the genus Delphinus, and use molecular markers to address questions about speciation and the evolution of population structure. Delphinus species have a worldwide distribution and show a high degree of morphological variation. Two distinct morphotypes, long-beaked and short-beaked, have been considered different species named D. capensis and D. delphis, respectively. However, genetic differentiation between these two forms has only been demonstrated in the Pacific. We analysed samples from eight different geographical regions, including two morphologically defined long-beaked form populations, and compared these with the eastern North Pacific populations. We found high differentiation among the populations described as long-beaked instead of the expected monophyly, suggesting that these populations may have evolved from independent events converging on the same morphotype. We observed low genetic differentiation among the short-beaked populations across a large geographical scale. We interpret these phylogeographical patterns in the context of life history and population structure in related species.
The use of photo-identification and its reliability in capture-recapture studies of Mediterranean... more The use of photo-identification and its reliability in capture-recapture studies of Mediterranean monk seals were assessed using slides collected in the colony at Cap Blanc, western Sahara, from 1993 to 1996. Five tests indicated that researchers involved in photo-identification were proficient in matching slides of identified seals, consistent in classifying the side of the seal shown in slides and in assigning the morphological stage of the seal, and that changes of markings over a period of three years were insufficient to affect matching success. The certainty of identifying a seal was not dependent on the number of slides used but on distinctiveness of the markings and the quality of the slides taken. Capture-recapture abundance estimates were biased upwards when including poor quality slides. The exclusive use of excellent- and good quality slides provided the best estimates. The proportion of distinctive seals varied between morphological stages and was significantly lower in juveniles. When including the identification histories of juveniles, the heterogeneity of capture probabilities was higher. Therefore, abundance estimates were less biased when all juveniles were considered as non-distinctive seals. Reliable abundance estimates required a balance between duration of capture occasions and time interval between these.
Journal of Toxicology and Environmental Health-part A-current Issues, 2000
The reserve of Camargue e South of France is impacted by a myriad of pollutant organic persistent... more The reserve of Camargue e South of France is impacted by a myriad of pollutant organic persistent like PCBs.
The resolution of taxonomic classifications for delphinid cetaceans has been problematic, especia... more The resolution of taxonomic classifications for delphinid cetaceans has been problematic, especially for species in the genera Delphinus, Tursiops and Stenella. The frequent lack of correspondence between morphological and genetic differentiation in these species raises questions about the mechanisms responsible for their evolution. In this study we focus on the genus Delphinus, and use molecular markers to address questions about speciation and the evolution of population structure. Delphinus species have a worldwide distribution and show a high degree of morphological variation. Two distinct morphotypes, long-beaked and short-beaked, have been considered different species named D. capensis and D. delphis, respectively. However, genetic differentiation between these two forms has only been demonstrated in the Pacific. We analysed samples from eight different geographical regions, including two morphologically defined long-beaked form populations, and compared these with the eastern North Pacific populations. We found high differentiation among the populations described as long-beaked instead of the expected monophyly, suggesting that these populations may have evolved from independent events converging on the same morphotype. We observed low genetic differentiation among the short-beaked populations across a large geographical scale. We interpret these phylogeographical patterns in the context of life history and population structure in related species.
Genetic divergence among conspecific subpopulations can be due to either low recurrent gene flow ... more Genetic divergence among conspecific subpopulations can be due to either low recurrent gene flow or recent divergence and no gene flow. Here we present a modification of an earlier method developed by , which accommodates a finite-site mutation model, to assess which of the two models of divergence is most likely given the observed data. We apply the method to nucleotide sequence data collected from the variable part of the mitochondrial control region in fin whales (Balaenoptera physalus) from the Atlantic coast off Spain and the Mediterranean Sea. Our estimations strongly favor a model of recurrent gene flow over a model of recent divergence and zero gene flow. We estimated the migration rate at two females per generation. While the estimated rate is high by evolutionary standards, exchange rates of this order of magnitude is low from an ecological and conservation perspective and entirely consistent with the current paucity of fin whale sightings in the Strait of Gibraltar today. Intensive commercial shore-based whaling during the 1920s removed substantial numbers of fin whales in the Strait of Gibraltar and this local population has seemingly since failed to recover.
Journal of Toxicology and Environmental Health-part A-current Issues, 2000
The reserve of Camargue e South of France is impacted by a myriad of pollutant organic persistent... more The reserve of Camargue e South of France is impacted by a myriad of pollutant organic persistent like PCBs.
The concentration of DDTs and PCBs was determined in two strata (inner and outer) of the blubber ... more The concentration of DDTs and PCBs was determined in two strata (inner and outer) of the blubber of fin and sei whales from the eastern North Atlantic. In the two species residue levels of all organochlorines in the outer layer were significantly higher than in the inner one. The DDE/tDDT ratio did not show significant variation between strata, but the tDDT/PCB ratio was higher in the outer layer than in the inner one. Such differences between strata cannot be explained by variation in the quantity of lipids present in the blubber and probably indicate a constant organochlorine distribution pattern in the blubber of large whales. The differential role of the blubber strata in the fattening cycle, the heterogeneous lipid composition of blubber throughout its depth and the different turnover rates of pollutants in the layers are the probable factors responsible for these observed differences in pollutant distribution between blubber strata. Because of this heterogeneous distribution, blubber samples collected from cetaceans for pollutant analyses should include equal representation of all layers in order to be representative of the individual's pollutant load. This is especially important when sampling stranded specimens or taking biopsy samples from large free-ranging whales.
Genetic divergence among conspecific subpopulations can be due to either low recurrent gene flow ... more Genetic divergence among conspecific subpopulations can be due to either low recurrent gene flow or recent divergence and no gene flow. Here we present a modification of an earlier method developed by , which accommodates a finite-site mutation model, to assess which of the two models of divergence is most likely given the observed data. We apply the method to nucleotide sequence data collected from the variable part of the mitochondrial control region in fin whales (Balaenoptera physalus) from the Atlantic coast off Spain and the Mediterranean Sea. Our estimations strongly favor a model of recurrent gene flow over a model of recent divergence and zero gene flow. We estimated the migration rate at two females per generation. While the estimated rate is high by evolutionary standards, exchange rates of this order of magnitude is low from an ecological and conservation perspective and entirely consistent with the current paucity of fin whale sightings in the Strait of Gibraltar today. Intensive commercial shore-based whaling during the 1920s removed substantial numbers of fin whales in the Strait of Gibraltar and this local population has seemingly since failed to recover.
Total DDT burden and DDE percentage (DDE/DDT+TDE+DDE) in the blubber of fin and sei whales are hi... more Total DDT burden and DDE percentage (DDE/DDT+TDE+DDE) in the blubber of fin and sei whales are highly correlated. Total DDT concentration may be an important source of variation for the DDE percentage detected in different individuals of the same population. Such a positive correlation is explained by the intensification of the dehydrochlorinative and differential excretive functions at higher pollutant levels. In the past, variations in the DDE percentage have been attributed to differences in the chronology of DDT input into the ecosystem and assumed to be indicators of population discreteness or changes in the pattern of DDT exposure of a given population. However, changes in the DDE percentage as related to total DDT burden may be important within the observed normal ranges of variation of total DDT residue levels caused by age and sex composition of the population. Therefore, the DDE percentage may be reliably used only when full control of the life history parameters of the sample is achieved and when strict homogeneity among the samples to be compared has been proved.
The concentration of DDTs and PCBs was determined in two strata (inner and outer) of the blubber ... more The concentration of DDTs and PCBs was determined in two strata (inner and outer) of the blubber of fin and sei whales from the eastern North Atlantic. In the two species residue levels of all organochlorines in the outer layer were significantly higher than in the inner one. The DDE/tDDT ratio did not show significant variation between strata, but the tDDT/PCB ratio was higher in the outer layer than in the inner one. Such differences between strata cannot be explained by variation in the quantity of lipids present in the blubber and probably indicate a constant organochlorine distribution pattern in the blubber of large whales. The differential role of the blubber strata in the fattening cycle, the heterogeneous lipid composition of blubber throughout its depth and the different turnover rates of pollutants in the layers are the probable factors responsible for these observed differences in pollutant distribution between blubber strata. Because of this heterogeneous distribution, blubber samples collected from cetaceans for pollutant analyses should include equal representation of all layers in order to be representative of the individual's pollutant load. This is especially important when sampling stranded specimens or taking biopsy samples from large free-ranging whales.
Canadian Journal of Zoology-revue Canadienne De Zoologie, 1991
... Duguy 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 198... more ... Duguy 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, Duguy and Budker ... After combining the sexes, body length at birth was determined by comparing maximum lengths of foetuses, mean lengths of neonates, and ...
Total DDT burden and DDE percentage (DDE/DDT+TDE+DDE) in the blubber of fin and sei whales are hi... more Total DDT burden and DDE percentage (DDE/DDT+TDE+DDE) in the blubber of fin and sei whales are highly correlated. Total DDT concentration may be an important source of variation for the DDE percentage detected in different individuals of the same population. Such a positive correlation is explained by the intensification of the dehydrochlorinative and differential excretive functions at higher pollutant levels. In the past, variations in the DDE percentage have been attributed to differences in the chronology of DDT input into the ecosystem and assumed to be indicators of population discreteness or changes in the pattern of DDT exposure of a given population. However, changes in the DDE percentage as related to total DDT burden may be important within the observed normal ranges of variation of total DDT residue levels caused by age and sex composition of the population. Therefore, the DDE percentage may be reliably used only when full control of the life history parameters of the sample is achieved and when strict homogeneity among the samples to be compared has been proved.
Canadian Journal of Zoology-revue Canadienne De Zoologie, 1991
... Duguy 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 198... more ... Duguy 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, Duguy and Budker ... After combining the sexes, body length at birth was determined by comparing maximum lengths of foetuses, mean lengths of neonates, and ...
Organochlorine pollutants are potentially useful for identifying discrete populations of marine m... more Organochlorine pollutants are potentially useful for identifying discrete populations of marine mammals that overlap in geographic distribution. However, many factors unrelated to geographical distribution may affect the chemical burden of individual animals or of entire population components even within a homogeneously distributed population. These factors include. among others, nutritional state, sex, age, trophic level, distance of habitat from mainland and pollution source, excretion. metabolism, and tissue composition. Sample storage and analytical methodology may also be an important source of variation. These, and any other factors, must be identified and their effect ascertained before attempting any comparison between populations. This paper critically examines the nature and magnitude of the effects of these factors on organochlorine tissue loads in marine mammals. Pollutant concentrations can be strongly biased if carefully designed sampling regimes are not followed, but they are affected only moderately by sample treatment after collection. Conversely, ratios between concentrations of compounds, such as the DDE/tDDT or the tDDT/PCB ratios, seem less dependent on sampling regime but more affected by storage. analytical procedures and ecological variations such as distance from pollutant source or trophic level. Taking these effects into account, advice is provided about sampling and strategies for selection of variables that will improve the reliability of the comparisons between populations.
Individual PCB congener concentrations, including non-ortho chloro substituted, were determined i... more Individual PCB congener concentrations, including non-ortho chloro substituted, were determined in 30 striped dolphins (Stenella coeruleoalba) affected by the 1990–1992 Mediterranean epizootic to investigate their toxic potential. PCB congener concentrations in these dolphins were among the highest ever found in comparable studies on marine mammals. Concentrations in males and females were significantly different because of pollutant transfer to offspring by females. Thus, PCB concentrations and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalents (TEO) in males were approximately double those in females. Non-ortho, mono-ortho and di-ortho coplanar congeners accounted for approximately one third of the overall toxicity assessed through toxic equivalent factors (TEFs), as defined by Ahlborg et al. (1994). Di-ortho congener 170 and non- ortho congener 126 were the major contributors to TEQ (33% and 30% respectively).
Background: Studies of population biology are scarce in Mediterranean striped dolphins (Stenella ... more Background: Studies of population biology are scarce in Mediterranean striped dolphins (Stenella coeruleoalba) mostly because of the lack of samples. Until now, studies of physical maturity, growth, and development of the flipper bones were not available for this species in the Mediterranean.
Background: Studies of population biology are scarce in Mediterranean striped dolphins (Stenella ... more Background: Studies of population biology are scarce in Mediterranean striped dolphins (Stenella coeruleoalba) mostly because of the lack of samples. Until now, studies of physical maturity, growth, and development of the flipper bones were not available for this species in the Mediterranean.
The use of photo-identification and its reliability in capture-recapture studies of Mediterranean... more The use of photo-identification and its reliability in capture-recapture studies of Mediterranean monk seals were assessed using slides collected in the colony at Cap Blanc, western Sahara, from 1993 to 1996. Five tests indicated that researchers involved in photo-identification were proficient in matching slides of identified seals, consistent in classifying the side of the seal shown in slides and in assigning the morphological stage of the seal, and that changes of markings over a period of three years were insufficient to affect matching success. The certainty of identifying a seal was not dependent on the number of slides used but on distinctiveness of the markings and the quality of the slides taken. Capture-recapture abundance estimates were biased upwards when including poor quality slides. The exclusive use of excellent- and good quality slides provided the best estimates. The proportion of distinctive seals varied between morphological stages and was significantly lower in juveniles. When including the identification histories of juveniles, the heterogeneity of capture probabilities was higher. Therefore, abundance estimates were less biased when all juveniles were considered as non-distinctive seals. Reliable abundance estimates required a balance between duration of capture occasions and time interval between these.
The resolution of taxonomic classifications for delphinid cetaceans has been problematic, especia... more The resolution of taxonomic classifications for delphinid cetaceans has been problematic, especially for species in the genera Delphinus, Tursiops and Stenella. The frequent lack of correspondence between morphological and genetic differentiation in these species raises questions about the mechanisms responsible for their evolution. In this study we focus on the genus Delphinus, and use molecular markers to address questions about speciation and the evolution of population structure. Delphinus species have a worldwide distribution and show a high degree of morphological variation. Two distinct morphotypes, long-beaked and short-beaked, have been considered different species named D. capensis and D. delphis, respectively. However, genetic differentiation between these two forms has only been demonstrated in the Pacific. We analysed samples from eight different geographical regions, including two morphologically defined long-beaked form populations, and compared these with the eastern North Pacific populations. We found high differentiation among the populations described as long-beaked instead of the expected monophyly, suggesting that these populations may have evolved from independent events converging on the same morphotype. We observed low genetic differentiation among the short-beaked populations across a large geographical scale. We interpret these phylogeographical patterns in the context of life history and population structure in related species.
The use of photo-identification and its reliability in capture-recapture studies of Mediterranean... more The use of photo-identification and its reliability in capture-recapture studies of Mediterranean monk seals were assessed using slides collected in the colony at Cap Blanc, western Sahara, from 1993 to 1996. Five tests indicated that researchers involved in photo-identification were proficient in matching slides of identified seals, consistent in classifying the side of the seal shown in slides and in assigning the morphological stage of the seal, and that changes of markings over a period of three years were insufficient to affect matching success. The certainty of identifying a seal was not dependent on the number of slides used but on distinctiveness of the markings and the quality of the slides taken. Capture-recapture abundance estimates were biased upwards when including poor quality slides. The exclusive use of excellent- and good quality slides provided the best estimates. The proportion of distinctive seals varied between morphological stages and was significantly lower in juveniles. When including the identification histories of juveniles, the heterogeneity of capture probabilities was higher. Therefore, abundance estimates were less biased when all juveniles were considered as non-distinctive seals. Reliable abundance estimates required a balance between duration of capture occasions and time interval between these.
Journal of Toxicology and Environmental Health-part A-current Issues, 2000
The reserve of Camargue e South of France is impacted by a myriad of pollutant organic persistent... more The reserve of Camargue e South of France is impacted by a myriad of pollutant organic persistent like PCBs.
The resolution of taxonomic classifications for delphinid cetaceans has been problematic, especia... more The resolution of taxonomic classifications for delphinid cetaceans has been problematic, especially for species in the genera Delphinus, Tursiops and Stenella. The frequent lack of correspondence between morphological and genetic differentiation in these species raises questions about the mechanisms responsible for their evolution. In this study we focus on the genus Delphinus, and use molecular markers to address questions about speciation and the evolution of population structure. Delphinus species have a worldwide distribution and show a high degree of morphological variation. Two distinct morphotypes, long-beaked and short-beaked, have been considered different species named D. capensis and D. delphis, respectively. However, genetic differentiation between these two forms has only been demonstrated in the Pacific. We analysed samples from eight different geographical regions, including two morphologically defined long-beaked form populations, and compared these with the eastern North Pacific populations. We found high differentiation among the populations described as long-beaked instead of the expected monophyly, suggesting that these populations may have evolved from independent events converging on the same morphotype. We observed low genetic differentiation among the short-beaked populations across a large geographical scale. We interpret these phylogeographical patterns in the context of life history and population structure in related species.
Genetic divergence among conspecific subpopulations can be due to either low recurrent gene flow ... more Genetic divergence among conspecific subpopulations can be due to either low recurrent gene flow or recent divergence and no gene flow. Here we present a modification of an earlier method developed by , which accommodates a finite-site mutation model, to assess which of the two models of divergence is most likely given the observed data. We apply the method to nucleotide sequence data collected from the variable part of the mitochondrial control region in fin whales (Balaenoptera physalus) from the Atlantic coast off Spain and the Mediterranean Sea. Our estimations strongly favor a model of recurrent gene flow over a model of recent divergence and zero gene flow. We estimated the migration rate at two females per generation. While the estimated rate is high by evolutionary standards, exchange rates of this order of magnitude is low from an ecological and conservation perspective and entirely consistent with the current paucity of fin whale sightings in the Strait of Gibraltar today. Intensive commercial shore-based whaling during the 1920s removed substantial numbers of fin whales in the Strait of Gibraltar and this local population has seemingly since failed to recover.
Journal of Toxicology and Environmental Health-part A-current Issues, 2000
The reserve of Camargue e South of France is impacted by a myriad of pollutant organic persistent... more The reserve of Camargue e South of France is impacted by a myriad of pollutant organic persistent like PCBs.
The concentration of DDTs and PCBs was determined in two strata (inner and outer) of the blubber ... more The concentration of DDTs and PCBs was determined in two strata (inner and outer) of the blubber of fin and sei whales from the eastern North Atlantic. In the two species residue levels of all organochlorines in the outer layer were significantly higher than in the inner one. The DDE/tDDT ratio did not show significant variation between strata, but the tDDT/PCB ratio was higher in the outer layer than in the inner one. Such differences between strata cannot be explained by variation in the quantity of lipids present in the blubber and probably indicate a constant organochlorine distribution pattern in the blubber of large whales. The differential role of the blubber strata in the fattening cycle, the heterogeneous lipid composition of blubber throughout its depth and the different turnover rates of pollutants in the layers are the probable factors responsible for these observed differences in pollutant distribution between blubber strata. Because of this heterogeneous distribution, blubber samples collected from cetaceans for pollutant analyses should include equal representation of all layers in order to be representative of the individual's pollutant load. This is especially important when sampling stranded specimens or taking biopsy samples from large free-ranging whales.
Genetic divergence among conspecific subpopulations can be due to either low recurrent gene flow ... more Genetic divergence among conspecific subpopulations can be due to either low recurrent gene flow or recent divergence and no gene flow. Here we present a modification of an earlier method developed by , which accommodates a finite-site mutation model, to assess which of the two models of divergence is most likely given the observed data. We apply the method to nucleotide sequence data collected from the variable part of the mitochondrial control region in fin whales (Balaenoptera physalus) from the Atlantic coast off Spain and the Mediterranean Sea. Our estimations strongly favor a model of recurrent gene flow over a model of recent divergence and zero gene flow. We estimated the migration rate at two females per generation. While the estimated rate is high by evolutionary standards, exchange rates of this order of magnitude is low from an ecological and conservation perspective and entirely consistent with the current paucity of fin whale sightings in the Strait of Gibraltar today. Intensive commercial shore-based whaling during the 1920s removed substantial numbers of fin whales in the Strait of Gibraltar and this local population has seemingly since failed to recover.
Total DDT burden and DDE percentage (DDE/DDT+TDE+DDE) in the blubber of fin and sei whales are hi... more Total DDT burden and DDE percentage (DDE/DDT+TDE+DDE) in the blubber of fin and sei whales are highly correlated. Total DDT concentration may be an important source of variation for the DDE percentage detected in different individuals of the same population. Such a positive correlation is explained by the intensification of the dehydrochlorinative and differential excretive functions at higher pollutant levels. In the past, variations in the DDE percentage have been attributed to differences in the chronology of DDT input into the ecosystem and assumed to be indicators of population discreteness or changes in the pattern of DDT exposure of a given population. However, changes in the DDE percentage as related to total DDT burden may be important within the observed normal ranges of variation of total DDT residue levels caused by age and sex composition of the population. Therefore, the DDE percentage may be reliably used only when full control of the life history parameters of the sample is achieved and when strict homogeneity among the samples to be compared has been proved.
The concentration of DDTs and PCBs was determined in two strata (inner and outer) of the blubber ... more The concentration of DDTs and PCBs was determined in two strata (inner and outer) of the blubber of fin and sei whales from the eastern North Atlantic. In the two species residue levels of all organochlorines in the outer layer were significantly higher than in the inner one. The DDE/tDDT ratio did not show significant variation between strata, but the tDDT/PCB ratio was higher in the outer layer than in the inner one. Such differences between strata cannot be explained by variation in the quantity of lipids present in the blubber and probably indicate a constant organochlorine distribution pattern in the blubber of large whales. The differential role of the blubber strata in the fattening cycle, the heterogeneous lipid composition of blubber throughout its depth and the different turnover rates of pollutants in the layers are the probable factors responsible for these observed differences in pollutant distribution between blubber strata. Because of this heterogeneous distribution, blubber samples collected from cetaceans for pollutant analyses should include equal representation of all layers in order to be representative of the individual's pollutant load. This is especially important when sampling stranded specimens or taking biopsy samples from large free-ranging whales.
Canadian Journal of Zoology-revue Canadienne De Zoologie, 1991
... Duguy 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 198... more ... Duguy 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, Duguy and Budker ... After combining the sexes, body length at birth was determined by comparing maximum lengths of foetuses, mean lengths of neonates, and ...
Total DDT burden and DDE percentage (DDE/DDT+TDE+DDE) in the blubber of fin and sei whales are hi... more Total DDT burden and DDE percentage (DDE/DDT+TDE+DDE) in the blubber of fin and sei whales are highly correlated. Total DDT concentration may be an important source of variation for the DDE percentage detected in different individuals of the same population. Such a positive correlation is explained by the intensification of the dehydrochlorinative and differential excretive functions at higher pollutant levels. In the past, variations in the DDE percentage have been attributed to differences in the chronology of DDT input into the ecosystem and assumed to be indicators of population discreteness or changes in the pattern of DDT exposure of a given population. However, changes in the DDE percentage as related to total DDT burden may be important within the observed normal ranges of variation of total DDT residue levels caused by age and sex composition of the population. Therefore, the DDE percentage may be reliably used only when full control of the life history parameters of the sample is achieved and when strict homogeneity among the samples to be compared has been proved.
Canadian Journal of Zoology-revue Canadienne De Zoologie, 1991
... Duguy 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 198... more ... Duguy 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, Duguy and Budker ... After combining the sexes, body length at birth was determined by comparing maximum lengths of foetuses, mean lengths of neonates, and ...
Organochlorine pollutants are potentially useful for identifying discrete populations of marine m... more Organochlorine pollutants are potentially useful for identifying discrete populations of marine mammals that overlap in geographic distribution. However, many factors unrelated to geographical distribution may affect the chemical burden of individual animals or of entire population components even within a homogeneously distributed population. These factors include. among others, nutritional state, sex, age, trophic level, distance of habitat from mainland and pollution source, excretion. metabolism, and tissue composition. Sample storage and analytical methodology may also be an important source of variation. These, and any other factors, must be identified and their effect ascertained before attempting any comparison between populations. This paper critically examines the nature and magnitude of the effects of these factors on organochlorine tissue loads in marine mammals. Pollutant concentrations can be strongly biased if carefully designed sampling regimes are not followed, but they are affected only moderately by sample treatment after collection. Conversely, ratios between concentrations of compounds, such as the DDE/tDDT or the tDDT/PCB ratios, seem less dependent on sampling regime but more affected by storage. analytical procedures and ecological variations such as distance from pollutant source or trophic level. Taking these effects into account, advice is provided about sampling and strategies for selection of variables that will improve the reliability of the comparisons between populations.
Individual PCB congener concentrations, including non-ortho chloro substituted, were determined i... more Individual PCB congener concentrations, including non-ortho chloro substituted, were determined in 30 striped dolphins (Stenella coeruleoalba) affected by the 1990–1992 Mediterranean epizootic to investigate their toxic potential. PCB congener concentrations in these dolphins were among the highest ever found in comparable studies on marine mammals. Concentrations in males and females were significantly different because of pollutant transfer to offspring by females. Thus, PCB concentrations and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalents (TEO) in males were approximately double those in females. Non-ortho, mono-ortho and di-ortho coplanar congeners accounted for approximately one third of the overall toxicity assessed through toxic equivalent factors (TEFs), as defined by Ahlborg et al. (1994). Di-ortho congener 170 and non- ortho congener 126 were the major contributors to TEQ (33% and 30% respectively).
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