Análisis de la comunidad de odontocetos y la relación con su ambiente, en el extremo sur-occidental del Golfo de California, México (2003-2006 )

Tesis (Maestría en Ciencias en Manejo de Recursos Marinos), Instituto Politécnico Nacional, CICIMAR, 2008, 1 archivo PDF, (63 páginas). tesis.ipn.m

Variabilidad climática de gran escala y sus efectos ecológicos en el Pacífico mexicano

En el presente estudio se caracterizó la variabilidad ambiental de gran escala (interanual y multidecadal) y sus efectos ecológicos sobre las poblaciones naturales en aguas del Pacífico mexicano y regiones oceánicas adyacentes. A partir de los resultados se identifican tres escalas de variación en el Pacífico mexicano: la escala interanual relacionada con la variabilidad del El Niño/a Oscilación del Sur (ENSO) y la escala cuasidecadal y la multidecadal, asociadas a modos de variación climática del Pacífico Norte. A escala interanual se ha observado que los cambios en la ocurrencia de la ballena de Bryde (Balaenoptera edeni) en la Bahía de La Paz están influenciados por la variabilidad del ENSO y probablemente estén mediados por la disponibilidad de sus presas. A escalas cuasidecadales se observa que los vientos tehuanos son una fuente de variabilidad climática extratropical en el Pacífico Oriental Tropical; esta señal de baja frecuencia en los tehuanos puede ser modelada por la variación extratropical del sistema de alta presión del Pacífico Noreste, siendo su teleconexión el movimiento hacia el sur de los frentes fríos que bajan por Norteamérica desde el Pacífico Noreste. A escala multidecadal se distinguen con claridad la alternancia de periodos de enfriamiento y calentamiento en la Corriente de California durante los últimos 110 años. Estos cambios en la temperatura superficial del mar son indicativos de cambios en la circulación oceánica y atmosférica, que en última instancia, afectan los mecanismos de enriquecimiento de las aguas superficiales en toda la cuenca del Pacífico Norte. Esta señal de baja frecuencia representa la variación del régimen. Las respuestas biológicas documentadas relacionadas con esta escala de variación incluyen: 1) la expansión y contracción de poblaciones de la sardina de California (Sardinops sagax caerulea) y el calamar gigante (Dosidicus gigas), 2) cambios en la distribución en delfines comunes (Delphinus sp.), y 3) cambios en los patrones de migración de la ballena azul (Balaenoptera musculus); asimismo la evidencia sugiere cambios de largo plazo en la distribución de ballena gris (Eschrichtius robustus), ballena de aleta (Balaenoptera physalus), delfín de costados blancos (Lagenorhynchus obliquidens) y cachalotes (Physeter macrocephalus) que podrían estar relacionados con este tipo de variación multidecadal.ABSTRACT: In the present study large-scale environmental variability (interannual and multidecadal) and their ecological effects on marine populations in the Mexican Pacific and adjacent oceanic regions were characterized. From the results, three scales of variability were identifying in the Mexican Pacific: the interannual scale, associated with the El Niño/a southern oscillation (ENSO); and the quasidecadal and multidecadal scales associated with North Pacific climate variability. At the interannual scale, it was observed that the occurrences of Bryde’s whales at La Paz Bay are driven by the ENSO variability and are probably mediated by their prey availability. At quasidecadal scales, the Tehuantepec gap winds are a source of extratropical climate variability in the Eastern Tropical Pacific. This low frequency signal in the Tehuantepec gap winds could be driven by the extratropical variability of the high-pressure system located in the Northeast Pacific, and the teleconnection is given by the southward movement of cold-surges that flow from the Northeast Pacific over North America. At multidecadal scale, the alternating of cooling and warming periods over the past 110 years in the California Current was clearly distinguished. These changes in sea surface temperature are indicative of changes in the ocean-atmosphere circulation, which ultimately affect the mechanisms of surface waters enrichment across the North Pacific basin and this low frequency signal represents the regime variability. The documented biological responses related to this scale of variation include: 1) the expansion and contraction of the California sardine and the giant squid populations, 2) changes in the distribution of common dolphins, and 3) changes in migration patterns of blue whales; further evidence suggests long-term changes in the distribution of gray whale, fin whale, Pacific white-sided dolphin and sperm whales that could be associated with this type of multidecadal variation

Variabilidad climática de gran escala y sus efectos ecológicos en el Pacífico mexicano.

En el presente estudio se caracterizó la variabilidad ambiental de gran escala (interanual y multidecadal) y sus efectos ecológicos sobre las poblaciones naturales en aguas del Pacífico mexicano y regiones oceánicas adyacentes. A partir de los resultados se identifican tres escalas de variación en el Pacífico mexicano: la escala interanual relacionada con la variabilidad del El Niño/a Oscilación del Sur (ENSO) y la escala cuasidecadal y la multidecadal, asociadas a modos de variación climática del Pacífico Norte. A escala interanual se ha observado que los cambios en la ocurrencia de la ballena de Bryde (Balaenoptera edeni) en la Bahía de La Paz están influenciados por la variabilidad del ENSO y probablemente estén mediados por la disponibilidad de sus presas. A escalas cuasidecadales se observa que los vientos tehuanos son una fuente de variabilidad climática extratropical en el Pacífico Oriental Tropical; esta señal de baja frecuencia en los tehuanos puede ser modelada por la variación extratropical del sistema de alta presión del Pacífico Noreste, siendo su teleconexión el movimiento hacia el sur de los frentes fríos que bajan por Norteamérica desde el Pacífico Noreste. A escala multidecadal se distinguen con claridad la alternancia de periodos de enfriamiento y calentamiento en la Corriente de California durante los últimos 110 años. Estos cambios en la temperatura superficial del mar son indicativos de cambios en la circulación oceánica y atmosférica, que en última instancia, afectan los mecanismos de enriquecimiento de las aguas superficiales en toda la cuenca del Pacífico Norte. Esta señal de baja frecuencia representa la variación del régimen. Las respuestas biológicas documentadas relacionadas con esta escala de variación incluyen: 1) la expansión y contracción de poblaciones de la sardina de California (Sardinops sagax caerulea) y el calamar gigante (Dosidicus gigas), 2) cambios en la distribución en delfines comunes (Delphinus sp.), y 3) cambios en los patrones de migración de la ballena azul (Balaenoptera musculus); asimismo la evidencia sugiere cambios de largo plazo en la distribución de ballena gris (Eschrichtius robustus), ballena de aleta (Balaenoptera physalus), delfín de costados blancos (Lagenorhynchus obliquidens) y cachalotes (Physeter macrocephalus) que podrían estar relacionados con este tipo de variación multidecadal

Drones, Gulls and Urbanity: Interaction between New Technologies and Human Subsidized Species in Coastal Areas

The use of drones has expanded the boundaries of several activities, which is expected to be utilized intensively in the near future. Interactions between urbanity and naturalness have been increasing while urban expansion amplifies the proximity between urban and natural areas. In this scenario, the interactions between drones and fauna could be augmented. Therefore, the aim of this study was to depict and evaluate the responses of the opportunistic and territorial seagull Larus livens to a small-sized drone during the non-breeding stage in urban areas and natural surroundings. The results evidenced that gulls do not react to drone sounds, coloration, or distance between them and the drone take-off spot. Clearly, the take-off vertical movement triggers an agonistic behavior that is more frequent in groups conformed by two adults, evidencing some kind of territorial response against the device, expressed as characteristic mobbing behavior. Thus, adult settled gulls in touristic and non-urbanized areas displayed agonistic behavior more frequently against the drone. Despite the coastal urban area being a free interaction environment, it evidences a low risk between drone management and territorial seabirds.Fil: Frixione, Martín Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; ArgentinaFil: Salvadeo, Christian. Universidad Autonoma de Baja California Sur; Estados Unido

Issues of ecosystem-based management of forage fisheries in “open” non-stationary ecosystems: the example of the sardine fishery in the Gulf of California

The Gulf of California system presents major challenges to the still developing frameworks for ecosystem-based management (EBM). It is very much an open system and is intermittently subject to important influxes of migratory visitors, including large pelagic predatory fishes and small pelagic forage fishes. These migrants include the more tropical species from the coastal ecosystems to the south and perhaps subtropical sardines and anchovies from the California Current upwelling system. In addition to the multi-annual ENSO-scale and what may seem to be rather erratic episodes of major population incursions, the Gulf presents nonstationary, transient aspects on a variety of longer time scales. Moreover, the removal of top predators by commercial and sport fisheries has introduced trends that must be affecting the entire ecosystem, and certainly the forage fishes that are their major prey base. In addition to size limits, fishing seasons, area closures and license limitations, the fishery is managed by an ad hoc adaptive management system, in which the fishing season can be shortened or additional areas closed to fishing if pre-season exploratory fishing surveys indicate a shortage of small pelagic fishes on the fishing grounds. Whether this system is likely to be sustainable in the long term is difficult to determine, given the potential for rapid changes in the system because of environmental changes and/or feedbacks within the food web. Thus it appears that innovative management frameworks, among other things utilizing the comparative method, may be required in order to determine defensible tradeoffs between precaution and resource utilization

The odontocete community and its environment in the southwestern Gulf of California

Community structure is a function of the number of species, their relative abundance and the characteristics of the dominant, common and rare species that are part of it. It also can be described by changes in its physical and biological environment. The aim of the present work is to describe the odontocete community, its temporal changes and the relationship with environmental variability and food availability in the southwestern Gulf of California (GC). Information was obtained from 21 sampling trips from September 2003 to March 2006 between La Paz Bay and Loreto, with a sampling effort of 8769.1km. We recorded the presence, location and other biological parameters of odontocete sightings. Data on environmental variability was obtained from satellite images of sea surface temperature and chlorophyll concentration, and food availability from published reports. A total of 30201 odontocete cetaceans were recorded from 353 sightings, belonging to 10 different species. We observed a temporal lag between the peaks in productivity and an increased presence of odontocete species. The community structure showed a seasonal change in the abundance of the dominant (Tursiops truncatus and Delphinus sp.) and common species (Globicephala macrorhynchus and Kogia sp.), as well as by the absence or presence of scarce (Physeter macrocephalus and Orcinus orca) and rare species (Pseudorca crassidens and Lagenorhynchus obliquidens). This seasonal community change is in agreement with the known seasonal movements of its main prey inside the GC, which, in turn, is related to seasonal environmental variation. We observed that the community structure was dominated by fish-eating species during the temperate season and responded to the increased presence and aggregation of sardines (Sardinops sagax caerulea) in the southern GC, whereas the warm season was dominated by squid-eating species and related to the increased presence and aggregation of the jumbo squid (Dosidicus gigas) in the GC’s west coast

The odontocete community and its environment in the southwestern Gulf of California

Community structure is a function of the number of species, their relative abundance and the characteristics of the dominant, common and rare species that are part of it. It also can be described by changes in its physical and biological environment. The aim of the present work is to describe the odontocete community, its temporal changes and the relationship with environmental variability and food availability in the southwestern Gulf of California (GC). Information was obtained from 21 sampling trips from September 2003 to March 2006 between La Paz Bay and Loreto, with a sampling effort of 8769.1km. We recorded the presence, location and other biological parameters of odontocete sightings. Data on environmental variability was obtained from satellite images of sea surface temperature and chlorophyll concentration, and food availability from published reports. A total of 30201 odontocete cetaceans were recorded from 353 sightings, belonging to 10 different species. We observed a temporal lag between the peaks in productivity and an increased presence of odontocete species. The community structure showed a seasonal change in the abundance of the dominant (Tursiops truncatus and Delphinus sp.) and common species (Globicephala macrorhynchus and Kogia sp.), as well as by the absence or presence of scarce (Physeter macrocephalus and Orcinus orca) and rare species (Pseudorca crassidens and Lagenorhynchus obliquidens). This seasonal community change is in agreement with the known seasonal movements of its main prey inside the GC, which, in turn, is related to seasonal environmental variation. We observed that the community structure was dominated by fish-eating species during the temperate season and responded to the increased presence and aggregation of sardines (Sardinops sagax caerulea) in the southern GC, whereas the warm season was dominated by squid-eating species and related to the increased presence and aggregation of the jumbo squid (Dosidicus gigas) in the GC’s west coast

Ecosystem-level effects of the small pelagics fishery in the Gulf of California

Documentary scientific evidence supports the notion that the small pelagics fishery in the Gulf of California does not measurably affect the physical habitat or the functional relationships between the species comprising the pelagic ecosystem. Also, there is little information that suggests any negative effects of the small pelagic fishery operations on critically endangered, endemic species, i.e., vaquita and totoaba. Under the current management regime, small pelagics fishery in the Gulf of California has recovered twice from collapses during the last 30 years. Although the small pelagics abundance varies greatly, the long-term productivity of the target species and the structure and function of the pelagic ecosystem are not compromised because the fishery relies on a suitable logistic and administrative platform, which is consistent with international standards for responsible fisheries, precautionary approach and ecosystem-based fisheries management principles

The importance of grey literature in fisheries ecology: an example based on the throphic role of small pelagics in the Gulf of California

La literatura gris suele considera se como una fuente de información cuestionable en revistas y publicaciones científicas debido a que carece de una revisión especializada ya que puede constituirse de documentos difíciles de rastrear. Sin embargo, brinda información detallada y de calidad que no se encuentra en las publicaciones con arbitraje estricto. Con el objetivo de ilustrar la importancia de la literatura gris en el ámbito de la ecología pesquera, se realizó una búsqueda en línea de publicaciones en revistas indexadas, en tesis de grado, re portes técnicos y resúmenes de congresos donde se reportan las relaciones tróficas de los pelágicos menores con especies de diversos taxa en el Golfo de California. Se obtuvo un total de 57 referencias bibliográficas de las cuales 36 son consideradas como literatura gris. Excluir los datos contenidos en estas fuentes de los análisis que se lleven a cabo sobre el tema, podría representar una pérdida de más del 60% de la información disponible. Este sesgo tiene el potencial de producir conclusiones incompletas o erróneas en los estudios de la dinámica trófica de los pelágicos menores en el Golfo de California