Paloma Ladrón de Guevara P. (original) (raw)
Papers by Paloma Ladrón de Guevara P.
CIENCIA 70(3):37-47, 2019
El manatí es un mamífero acuático herbívoro y de hábitos costeros. Poblaciones importantes de est... more El manatí es un mamífero acuático herbívoro y de hábitos costeros. Poblaciones importantes de estos animales se encuentran en los sistemas fluvio-lagunares y costas del Golfo de México y el mar Caribe, donde también hay una gran actividad humana que los pone en alto riesgo y afecta de manera negativa. Hoy esta especie se encuentra en peligro de extinción y para su conservación es necesario involucrar a la población local con la cual interactúa constantemente.
Revista Mexicana de Biodiversidad, 2019
The manatee (Trichechus manatus manatus) is an aquatic mammal that is in danger of extinction. An... more The manatee (Trichechus manatus manatus) is an aquatic mammal that is in danger of extinction. An important population of this species is found in the fluvio-lagoon systems that connect with the Términos Lagoon, Campeche, The manatee (Trichechus manatus manatus) is an aquatic mammal that is in danger of extinction. An important
population of this species is found in the fluvio-lagoon systems that connect with the Términos Lagoon, Campeche,
Canadian Journal of Zoology-Revue Canadienne de Zoologie 72(10), 1994
A B S T R A C T The purpose of this article is to present the Mexican experience related to the U... more A B S T R A C T The purpose of this article is to present the Mexican experience related to the US-Mexico joint Gulf of Mexico Large Marine Ecosystem-Based Assessment and Management Project, particularly the community involvement and mangrove wetland restoration, and the challenges for its replication and up-scaling. Results focus on community engagement, environmental education and social participation, strategies for hydrological restoration of mangrove, and difficulties and recommendations for the implementation of the Strategic Action Program. The main conclusions are that the community-based hydrologic restoration approach, is a good way to ensure long-term restoration of wetlands. Changing from mangrove plantations to the hydrological restoration of wetlands, and construction of human capacities resulted in a more efficient strategy for ecosystem restoration and had influenced the forest environmental policy. The involvement of government and education institutions as execution agencies will contribute to a more efficient appropriation of the project and LME approach. The development of economic alternatives and the ecological monitoring are some of the identified challenges within the implementation phase of the Strategic Action Program.
The sex of 43 humpback whales (Megaptera novaeangliae) from different social groupings in the Mex... more The sex of 43 humpback whales (Megaptera novaeangliae) from different social groupings in the Mexican Pacific was identified
by a molecular analysis of skin biopsy samples. Of the 18 whales sampled from surface-active groups, 17 were males.
Three singers were sampled and identified as males. In two cases, whales interrupting and joining a singer without exhibiting agonistic behavior were identified as females. A higher proportion of males was found in the samples collected at the Revillagigedo Islands, reflecting a greater sampling effort on surface-active groups. Preliminary data showed that along the Mexican Pacific coast, the migratory arrival of males corresponds closely to the timing of competitive activity.
Ventral fluke patterns of humpback whales Megaptera novaeangliae were assessed to determine if pi... more Ventral fluke patterns of humpback whales Megaptera novaeangliae were assessed to determine if pigmentation shows geographical variation across different breeding areas. Fluke photographs (n = 3854) were collected from 7 major breeding grounds worldwide and were ranked into categories 1 (white) through 5 (black) based on the proportion of white and black pigment on the ventral surface. Average coloration varied primarily between oceanic populations, with the Southern Ocean stocks (Area IV, western Australia, and Area V, eastern Australia) characterized by significantly more light-colored flukes, while the North Pacific subpopulations consisted of individuals with significantly more dark-colored flukes. Results of statistical analyses revealed that all populahons differed significantly from one another in the distribution of pigmentation classes, with the exceptions of Hawaii vs Japan, Mexico vs Japan, Mexico vs Hawaii, eastern Australia vs western Australia, and West Indies vs Colombia. Results of pigmentation analyses reveal historic and current interactions among oceanic subpopulations of humpback whales and reflect population subdivision in this species.
The migratory destinations of humpback whales that feed off California. Oregon and Washington wer... more The migratory destinations of humpback whales that feed off California. Oregon and Washington were determined using photo-identification. Fluke photographs of 594 individuals were taken between 1981 and 1992 and compared to collections from 9 wintering regions in the North Pacific: Ogasawara (162) and Okinawa (17) islands of Japan; the Big Island and Maui (634 for both) and Kauai (384) of Hawaii; the Revillagigedo Archipelago (450), the mainland coast (383) and Baja Peninsula (471) of Mexico; and Central America (31). A total of 160 matches were found to 6 central and eastern North Paclfic wintering regions, with most from Central America, Baja, and mainland Mexico. Of whales identified off Central America, 84 % were resighted off California-Washington, this high rate of interchange suggests that whales in these tropical waters appear to be comprised entirely of animals from the California-Washington feeding aggregation. Humpback whales seen off Central America were reslghted disproportionately off southern California while those from mainland ~Vexico tended to be seen off northern California-Washington. From 157 same-season migratory transits documented, the shortest were 29 d to Baja and 56 d to Costa Rica and the longest distance was 5322 km. Of the Cal-ifornia-Washington whales with known sex, the proportion of males identified at a wintering region was significantly higher than females (2.2:1, p < 0.05).
We examined the incidence of rake mark scars from killer whales Orcinus orca on the flukes of hum... more We examined the incidence of rake mark scars from killer whales Orcinus orca on the flukes of humpback whales Megaptera novaeangliae throughout the North Pacific to assess geographic variation in predation pressure. We used 3650 identification photographs from 16 wintering or feeding areas collected during 1990 to 1993 to determine conservative estimates in the percentage of whales with rake mark scarring. Dramatic differences were seen in the incidence of rake marks among regions, with highest rates on wintering grounds off Mexico (26 vs. 14% at others) and feeding areas off California (20 vs. 6% at others), 2 areas between which humpback whales migrate. Although attacks are rarely witnessed, the prevalence of scars demonstrates that a substantial portion of animals are attacked, particularly those that migrate between California and Mexico. Our data also suggest that most attacks occur at or near the wintering grounds in the eastern North Pacific. The prevalence of attacks indicates that killer whale predation has the potential to be a major cause of mortality and a driving force in migratory behavior; however, the location of the attacks is inconsistent with the hypothesis that animals migrate to tropical waters to avoid predation. Our conclusion is that, at least in recent decades, attacks are made primarily on calves at the wintering grounds; this contradicts the hypothesis that killer whales historically preyed heavily on large whales in high-latitude feeding areas in the North Pacific.
Fin whales (Balaenoptera physalus) are observed year-round in the Ballenas Channel and Bahía de l... more Fin whales (Balaenoptera physalus) are observed year-round in the Ballenas Channel and Bahía de los Ángeles region, Gulf of
California, where their main food item is the euphausiid Nyctiphanes simplex. This investigation was designed under the hypothesis that the spatial and temporal occurrence of whales and euphausiids coincides. The aim was to establish the geographic, seasonal, and interanual changes in the abundance of the fin whale and its main prey in the region during 2003 and 2004. Four field trips were carried out per year. Surveys to search for whales and carry out horizontal surface tows were conducted from small boats. Fin whales and euphausiids were mainly observed off the coast of Baja California and in the southern Ballenas Channel. Their abundance varied significantly from one season to another
in both years. The highest relative abundance of whales occurred in July (warm season), followed by June (cold–warm transition period) and March–April (cold season), and the lowest in October (late warm season). Euphausiid abundance was significantly higher in June (cold–warm transition period), followed by July (warm season). There was no direct correlation between weekly abundances of both species, probably
because whale peak abundance occurred four weeks later than euphausiid peak abundance. Fin whale relative abundance was significantly higher in 2004 than in 2003 (2.22 and 0.46 whales h–1, respectively), but euphausiid abundance remained almost the same (geometric means 255 and 174 ind/1000 m3). Even though there was no weekly correlation between both species, their geographic distribution did overlap.
Bahía de los Ángeles is located on the Baja Californian coast of the Gulf of California, adjacent... more Bahía de los Ángeles is located on the Baja Californian coast of the Gulf of California, adjacent to Ballenas Channel. The bay
receives a dynamic tidal influence from the channel but is protected by numerous islands. It is a highly productive bay that harbors a high
diversity of species, some of them protected such as the whale shark (Rhincodon typus). This study describes the seasonal variability of major
zooplankton taxa and copepod and cladoceran species between May 2003 and October 2004. Copepods were dominant during winter and
spring (83–99% of the zooplankton abundance), experiencing a dramatic decrease in autumn 2003 (37–66%) and summer 2004 (25–45%).
Cladocerans were the second most abundant group, represented by Pseudevadne tergestina and Penilia avirostris. The former species occurred
year-round with low abundance in winter, whereas the latter occurred only in summer and autumn. Other holozooplankton taxa contributed
with less than 15% of the abundance in most of the samples, while merozooplankton contributed less than 8%, though in October of 2003 and
2004 there was a remarkable abundance of echinoderms and other larvae contrasting with their shortage in other seasons. In winter 2004,
temperate-subtropical copepod species dominated, such as Calanus pacificus and Acartia tonsa. The high abundance of copepods during spring
obeyed to Acartia clausi (median = 28,034 ind m–3); however, the maximal zooplankton abundance (40,468 ind m–3, 99.5% copepods) came
from a sample collected south of Punta Arena, where two whale sharks were observed foraging. The shift in species composition during
summer coincides with the predominance of easterly winds described in the literature inducing a reversed circulation and a probable transport
of tropical species into the bay during summer and autumn (Centropages furcatus, Subeucalanus subcrassus, Acrocalanus longicornis, Temora
discaudata, and Corycaeus amazonicus).
We identified specific areas where fin whales (Balaenoptera physalus) forage on daytime surface s... more We identified specific areas where fin whales (Balaenoptera physalus) forage on daytime surface swarms of euphausiids in Ballenas Channel, Gulf of California. During 2003 and 2004, 4 field trips per year were carried out (winter–spring, spring, summer, and autumn). Systematic line transects and random surveys for whales were conducted in small boats (6 m) and euphausiid swarms were sampled with a zooplankton net. Fin whales foraged mostly in shallow waters (10–100 m) off the west and south coast of Coronado Island and were observed feeding on 18 of 19 swarms of Nyctiphanes simplex (5 in 2003 and 14 in 2004). Swarms occurred from March to early August and were almost absent from October to November. Although fin whales were sighted throughout the study area, there was a characteristic distribution pattern of feeding activity, mainly during spring and summer seasons. Examination of our data shows that the adjacent waters off Coronado Island constitute a unique seasonal foraging habitat for fin whales in the Gulf of California.
Books by Paloma Ladrón de Guevara P.
Bajo Tierra Ediciones, 2023
En el presente capítulo se presenta un resumen de la biodiversidad de la península de Yucatán, de... more En el presente capítulo se presenta un resumen de la biodiversidad de la península de Yucatán, de las áreas naturales y corredores biológicos que han contribuido a su conservación, los servicios ambientales que nos proporcionan, y se enfatiza en que para darle un uso sostenible y conservarla es indispensable la participación de la población local en alianza con la comunidad científica, los tres niveles de gobierno, la sociedad civil y todos los actores involucrados e interesados en su salvaguarda.
Ciencia, 2019
Los mamíferos marinos son animales que despiertan gran interés y curiosidad entre el público en g... more Los mamíferos marinos son animales que despiertan gran interés y curiosidad entre el público en general, pero muy a menudo la información proporcionada acerca de éstos es imprecisa o se basa en datos provenientes de otras regiones del mundo, por lo que no reflejan el amplio conocimiento que se tiene en México, donde se ha registrado la presencia de 52 de las 135 especies de mamíferos marinos que hay en el orbe, lo que significa una alta diversidad.
En este sentido, es de gran valor e importancia para la Sociedad Mexicana de Mastozoología Marina, A. C. (SOMEMMA) poder dar a conocer trabajos
e investigaciones reconocidos internacionalmente en torno a delfines, ballenas, marsopas, manatíes, lobos marinos, focas y nutrias. A partir de este esfuerzo, es de especial interés para la SOMEMMA motivar a los jóvenes para que incursionen en el estudio de los mamíferos marinos.
CIENCIA 70(3):37-47, 2019
El manatí es un mamífero acuático herbívoro y de hábitos costeros. Poblaciones importantes de est... more El manatí es un mamífero acuático herbívoro y de hábitos costeros. Poblaciones importantes de estos animales se encuentran en los sistemas fluvio-lagunares y costas del Golfo de México y el mar Caribe, donde también hay una gran actividad humana que los pone en alto riesgo y afecta de manera negativa. Hoy esta especie se encuentra en peligro de extinción y para su conservación es necesario involucrar a la población local con la cual interactúa constantemente.
Revista Mexicana de Biodiversidad, 2019
The manatee (Trichechus manatus manatus) is an aquatic mammal that is in danger of extinction. An... more The manatee (Trichechus manatus manatus) is an aquatic mammal that is in danger of extinction. An important population of this species is found in the fluvio-lagoon systems that connect with the Términos Lagoon, Campeche, The manatee (Trichechus manatus manatus) is an aquatic mammal that is in danger of extinction. An important
population of this species is found in the fluvio-lagoon systems that connect with the Términos Lagoon, Campeche,
Canadian Journal of Zoology-Revue Canadienne de Zoologie 72(10), 1994
A B S T R A C T The purpose of this article is to present the Mexican experience related to the U... more A B S T R A C T The purpose of this article is to present the Mexican experience related to the US-Mexico joint Gulf of Mexico Large Marine Ecosystem-Based Assessment and Management Project, particularly the community involvement and mangrove wetland restoration, and the challenges for its replication and up-scaling. Results focus on community engagement, environmental education and social participation, strategies for hydrological restoration of mangrove, and difficulties and recommendations for the implementation of the Strategic Action Program. The main conclusions are that the community-based hydrologic restoration approach, is a good way to ensure long-term restoration of wetlands. Changing from mangrove plantations to the hydrological restoration of wetlands, and construction of human capacities resulted in a more efficient strategy for ecosystem restoration and had influenced the forest environmental policy. The involvement of government and education institutions as execution agencies will contribute to a more efficient appropriation of the project and LME approach. The development of economic alternatives and the ecological monitoring are some of the identified challenges within the implementation phase of the Strategic Action Program.
The sex of 43 humpback whales (Megaptera novaeangliae) from different social groupings in the Mex... more The sex of 43 humpback whales (Megaptera novaeangliae) from different social groupings in the Mexican Pacific was identified
by a molecular analysis of skin biopsy samples. Of the 18 whales sampled from surface-active groups, 17 were males.
Three singers were sampled and identified as males. In two cases, whales interrupting and joining a singer without exhibiting agonistic behavior were identified as females. A higher proportion of males was found in the samples collected at the Revillagigedo Islands, reflecting a greater sampling effort on surface-active groups. Preliminary data showed that along the Mexican Pacific coast, the migratory arrival of males corresponds closely to the timing of competitive activity.
Ventral fluke patterns of humpback whales Megaptera novaeangliae were assessed to determine if pi... more Ventral fluke patterns of humpback whales Megaptera novaeangliae were assessed to determine if pigmentation shows geographical variation across different breeding areas. Fluke photographs (n = 3854) were collected from 7 major breeding grounds worldwide and were ranked into categories 1 (white) through 5 (black) based on the proportion of white and black pigment on the ventral surface. Average coloration varied primarily between oceanic populations, with the Southern Ocean stocks (Area IV, western Australia, and Area V, eastern Australia) characterized by significantly more light-colored flukes, while the North Pacific subpopulations consisted of individuals with significantly more dark-colored flukes. Results of statistical analyses revealed that all populahons differed significantly from one another in the distribution of pigmentation classes, with the exceptions of Hawaii vs Japan, Mexico vs Japan, Mexico vs Hawaii, eastern Australia vs western Australia, and West Indies vs Colombia. Results of pigmentation analyses reveal historic and current interactions among oceanic subpopulations of humpback whales and reflect population subdivision in this species.
The migratory destinations of humpback whales that feed off California. Oregon and Washington wer... more The migratory destinations of humpback whales that feed off California. Oregon and Washington were determined using photo-identification. Fluke photographs of 594 individuals were taken between 1981 and 1992 and compared to collections from 9 wintering regions in the North Pacific: Ogasawara (162) and Okinawa (17) islands of Japan; the Big Island and Maui (634 for both) and Kauai (384) of Hawaii; the Revillagigedo Archipelago (450), the mainland coast (383) and Baja Peninsula (471) of Mexico; and Central America (31). A total of 160 matches were found to 6 central and eastern North Paclfic wintering regions, with most from Central America, Baja, and mainland Mexico. Of whales identified off Central America, 84 % were resighted off California-Washington, this high rate of interchange suggests that whales in these tropical waters appear to be comprised entirely of animals from the California-Washington feeding aggregation. Humpback whales seen off Central America were reslghted disproportionately off southern California while those from mainland ~Vexico tended to be seen off northern California-Washington. From 157 same-season migratory transits documented, the shortest were 29 d to Baja and 56 d to Costa Rica and the longest distance was 5322 km. Of the Cal-ifornia-Washington whales with known sex, the proportion of males identified at a wintering region was significantly higher than females (2.2:1, p < 0.05).
We examined the incidence of rake mark scars from killer whales Orcinus orca on the flukes of hum... more We examined the incidence of rake mark scars from killer whales Orcinus orca on the flukes of humpback whales Megaptera novaeangliae throughout the North Pacific to assess geographic variation in predation pressure. We used 3650 identification photographs from 16 wintering or feeding areas collected during 1990 to 1993 to determine conservative estimates in the percentage of whales with rake mark scarring. Dramatic differences were seen in the incidence of rake marks among regions, with highest rates on wintering grounds off Mexico (26 vs. 14% at others) and feeding areas off California (20 vs. 6% at others), 2 areas between which humpback whales migrate. Although attacks are rarely witnessed, the prevalence of scars demonstrates that a substantial portion of animals are attacked, particularly those that migrate between California and Mexico. Our data also suggest that most attacks occur at or near the wintering grounds in the eastern North Pacific. The prevalence of attacks indicates that killer whale predation has the potential to be a major cause of mortality and a driving force in migratory behavior; however, the location of the attacks is inconsistent with the hypothesis that animals migrate to tropical waters to avoid predation. Our conclusion is that, at least in recent decades, attacks are made primarily on calves at the wintering grounds; this contradicts the hypothesis that killer whales historically preyed heavily on large whales in high-latitude feeding areas in the North Pacific.
Fin whales (Balaenoptera physalus) are observed year-round in the Ballenas Channel and Bahía de l... more Fin whales (Balaenoptera physalus) are observed year-round in the Ballenas Channel and Bahía de los Ángeles region, Gulf of
California, where their main food item is the euphausiid Nyctiphanes simplex. This investigation was designed under the hypothesis that the spatial and temporal occurrence of whales and euphausiids coincides. The aim was to establish the geographic, seasonal, and interanual changes in the abundance of the fin whale and its main prey in the region during 2003 and 2004. Four field trips were carried out per year. Surveys to search for whales and carry out horizontal surface tows were conducted from small boats. Fin whales and euphausiids were mainly observed off the coast of Baja California and in the southern Ballenas Channel. Their abundance varied significantly from one season to another
in both years. The highest relative abundance of whales occurred in July (warm season), followed by June (cold–warm transition period) and March–April (cold season), and the lowest in October (late warm season). Euphausiid abundance was significantly higher in June (cold–warm transition period), followed by July (warm season). There was no direct correlation between weekly abundances of both species, probably
because whale peak abundance occurred four weeks later than euphausiid peak abundance. Fin whale relative abundance was significantly higher in 2004 than in 2003 (2.22 and 0.46 whales h–1, respectively), but euphausiid abundance remained almost the same (geometric means 255 and 174 ind/1000 m3). Even though there was no weekly correlation between both species, their geographic distribution did overlap.
Bahía de los Ángeles is located on the Baja Californian coast of the Gulf of California, adjacent... more Bahía de los Ángeles is located on the Baja Californian coast of the Gulf of California, adjacent to Ballenas Channel. The bay
receives a dynamic tidal influence from the channel but is protected by numerous islands. It is a highly productive bay that harbors a high
diversity of species, some of them protected such as the whale shark (Rhincodon typus). This study describes the seasonal variability of major
zooplankton taxa and copepod and cladoceran species between May 2003 and October 2004. Copepods were dominant during winter and
spring (83–99% of the zooplankton abundance), experiencing a dramatic decrease in autumn 2003 (37–66%) and summer 2004 (25–45%).
Cladocerans were the second most abundant group, represented by Pseudevadne tergestina and Penilia avirostris. The former species occurred
year-round with low abundance in winter, whereas the latter occurred only in summer and autumn. Other holozooplankton taxa contributed
with less than 15% of the abundance in most of the samples, while merozooplankton contributed less than 8%, though in October of 2003 and
2004 there was a remarkable abundance of echinoderms and other larvae contrasting with their shortage in other seasons. In winter 2004,
temperate-subtropical copepod species dominated, such as Calanus pacificus and Acartia tonsa. The high abundance of copepods during spring
obeyed to Acartia clausi (median = 28,034 ind m–3); however, the maximal zooplankton abundance (40,468 ind m–3, 99.5% copepods) came
from a sample collected south of Punta Arena, where two whale sharks were observed foraging. The shift in species composition during
summer coincides with the predominance of easterly winds described in the literature inducing a reversed circulation and a probable transport
of tropical species into the bay during summer and autumn (Centropages furcatus, Subeucalanus subcrassus, Acrocalanus longicornis, Temora
discaudata, and Corycaeus amazonicus).
We identified specific areas where fin whales (Balaenoptera physalus) forage on daytime surface s... more We identified specific areas where fin whales (Balaenoptera physalus) forage on daytime surface swarms of euphausiids in Ballenas Channel, Gulf of California. During 2003 and 2004, 4 field trips per year were carried out (winter–spring, spring, summer, and autumn). Systematic line transects and random surveys for whales were conducted in small boats (6 m) and euphausiid swarms were sampled with a zooplankton net. Fin whales foraged mostly in shallow waters (10–100 m) off the west and south coast of Coronado Island and were observed feeding on 18 of 19 swarms of Nyctiphanes simplex (5 in 2003 and 14 in 2004). Swarms occurred from March to early August and were almost absent from October to November. Although fin whales were sighted throughout the study area, there was a characteristic distribution pattern of feeding activity, mainly during spring and summer seasons. Examination of our data shows that the adjacent waters off Coronado Island constitute a unique seasonal foraging habitat for fin whales in the Gulf of California.
Bajo Tierra Ediciones, 2023
En el presente capítulo se presenta un resumen de la biodiversidad de la península de Yucatán, de... more En el presente capítulo se presenta un resumen de la biodiversidad de la península de Yucatán, de las áreas naturales y corredores biológicos que han contribuido a su conservación, los servicios ambientales que nos proporcionan, y se enfatiza en que para darle un uso sostenible y conservarla es indispensable la participación de la población local en alianza con la comunidad científica, los tres niveles de gobierno, la sociedad civil y todos los actores involucrados e interesados en su salvaguarda.
Ciencia, 2019
Los mamíferos marinos son animales que despiertan gran interés y curiosidad entre el público en g... more Los mamíferos marinos son animales que despiertan gran interés y curiosidad entre el público en general, pero muy a menudo la información proporcionada acerca de éstos es imprecisa o se basa en datos provenientes de otras regiones del mundo, por lo que no reflejan el amplio conocimiento que se tiene en México, donde se ha registrado la presencia de 52 de las 135 especies de mamíferos marinos que hay en el orbe, lo que significa una alta diversidad.
En este sentido, es de gran valor e importancia para la Sociedad Mexicana de Mastozoología Marina, A. C. (SOMEMMA) poder dar a conocer trabajos
e investigaciones reconocidos internacionalmente en torno a delfines, ballenas, marsopas, manatíes, lobos marinos, focas y nutrias. A partir de este esfuerzo, es de especial interés para la SOMEMMA motivar a los jóvenes para que incursionen en el estudio de los mamíferos marinos.
