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1. Carbon and nitrogen stocks in sediment at Península Valdés Biosphere Reserve: novel insights into the potential contribution of large marine vertebrates to carbon sequestration

Author

Rocío Jiménez-Ramos, Luis G. Egea, Valeria C. D’Agostino, Mariana Degrati, and Rocío Loizaga

Subjects
blue carbon, Eubalaena australis, nitrogen sequestration, Otaria flavescens, salt marshes, southern right whales, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract

Although policymakers and stakeholders are beginning to acknowledge the importance of the marine biosphere in blue carbon services, the role of large marine vertebrates in the marine carbon and nitrogen cycle and especially in carbon sequestration has not yet been fully understood. Large marine vertebrates store only a small percentage of total oceanic carbon in their bodies, but they can provide important and lasting contributions to the oceanic carbon flux. The Península Valdés Biosphere Reserve in southwestern Argentina was partially established to conserve these large marine vertebrates, including the South American sea lion (Otaria flavescens) and southern right whale (Eubalaena australis). Three locations in Peninsula Valdés were sampling for the proximity of marine vertebrate populations in the area and the presence of salt marshes to assess the organic carbon (OC) and total nitrogen (TN) stocks in the top 1 m of sediment. Our work provides the first quantitative data on the OC and TN sequestered in the coastal sediments of Península Valdés and shows that this protected area contributes significantly to blue carbon by storing relevant quantities of OC (140 to 317 Mg OC ha-1) and nitrogen (7.3 to 22.9 Mg TN ha-1). Specifically, we found that salt marshes and terrestrial plants were the main C sources in each sediment core, but a non-negligible proportion (from 0.8 to 6.8% dry weight) of the OC stocks showed an isotopic signal from the large vertebrates that usually inhabit the area. Therefore, our results provide novel hypotheses about the potential contribution of large marine vertebrates as an OC vector in coastal systems and may serve as a basis for further investigation about their role into coastal blue carbon.

Published
2025
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3. Integrating Multiple Techniques to Estimate Population Size of an Impacted Dusky Dolphin’s Population in Patagonia, Argentina

Author

Mariana Degrati, Rocio Loizaga, Mariano A. Coscarella, Nicolás Sueyro, Enrique A. Crespo, and Silvana L. Dans

Subjects
effective population size, abundance, genetic, photo-identification, dusky dolphins, conservation, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract

Successful conservation strategies require an accurate estimation of population size, and this parameter is one of the most important factors that determine the rate of various evolutionary processes. In this study, we integrated information from genetic, photo-identification, and aerial surveys of dusky dolphins to determine the effective population size and the number of dolphins that inhabit the gulfs of Península Valdés [Golfo Nuevo (GN) and Golfo San José (GSJ)] and are exposed to tourism vessel traffic. Photo-identification sessions and biopsies samples were collected from a research vessel between 2004 and 2013 to estimate the number of dolphins in the area by capture–recapture methods and the effective population size using mtDNA data. In addition, four aerial surveys were carried out using line transects to estimate density via distance sampling. The long-term effective size estimated was 992.87–1,103.19 individuals. During the photo-identification period and by applying a mark rate of 0.416, the total estimated individuals in GN was 374 (95% CI: 237–511). For GSJ, the estimated individuals in the area were 55 (95% CI: 2–108, mark rate 0.692). From aerial surveys, the overall density estimate was D⌢ = 0.13 dolphins/km2 (95% CI: 0.052–0.35; CV: 49.60). The estimation for GN was 325 (95% CI: 130–875), whereas for GSJ, it was 104 (95% CI: 42–280) individuals. These are the first estimations of the number and the effective population size for dusky dolphins in a small-scale area along north Patagonia. Dusky dolphins groups are impacted by anthropogenic activities; therefore, the information reported here contributes population information to help to the species management and conservation.

Published
2020
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4. Reflexiones acerca del «reasilvestramiento» en la Argentina

Author

María de las Mercedes Guerisoli, Schiaffini, Mauro I., Pablo, Teta, Valenzuela, Alejandro E. J., Patricia, Mirol, Defossé, Guillermo E., María Marcela Godoy, Pablo, Krieger, Tomás, Withington, Agostini, María G., Anderson, Christopher B., Melina, Anello, Gustavo, Aprile, Aquino, Jesica E., Antonella Argoitia, M., Yanina, Arzamendia, Baigorria, Julián E. M., Diego, Baldo, Baldo, Jorge L., Ulises, Balza, Ian, Barbe, Barrasso, Diego A., Barri, Fernando R., Noelia Barrios-Garcia, M., Cristina, Bartolucci, Bastida, Ricardo O., Gabriel, Bauer, Pablo, Berrozpe, Claudio, Bertonatti, Roberto F., Bó, Bracamonte, Julio C., Campo, Denise H., Mariana, Cannizzo, Pablo, Carmanchahi, Flavia, Caruso, Flavia, Cassinelli, Chalukian, Silvia C., Chatellenaz, Mario L., Amelia Chemisquy, M., Mariana, Cosse, Cuyckens, Griet A. E., D’Agostino, Romina L., D’Agostino, Valeria C., Guillermo, Deferrari, Mariana, Degrati, Hebe del Valle Ferreyra, Derlindati, Enrique J., Sophia Di Cataldo, Florencia Di Rocco, Jael, Dominino, Durante, Cristian A., Eder, Elena B., Esquenazi, Sofía M., Ezquiaga, María C., Julián, Faivovich, Fernández, Fernando J., Nicolás, Ferreyra, Francisco Firpo Lacoste, David, Flores, Formoso, Anahí E., Franchini, Marcello, Francisco, Eduardo E., Gómez Fernández, María J., Baltazar, González, González, Enrique M., Susana, González, Guerrero, José C., Guiscafré, Agustín N., Juan, Ernesto E., Kin, Marta S., Martín, Kowalewski, Laitán, María G., Cecilia, Lanzone, Gabriel, Laufer, Carmen, Leizagoyen, Leonardi, María S., Rocío, Loizaga, Mapelli, Fernando J., Martin, Gabriel M., Guillermina, Massaccesi, Merani, María S., Julián, Mignino, Miño, Carolina I., Miotti, María D., Alejandro, Morici, Moschione, Flavio N., Mosti, Patricia A., Norberto, Muzzachiodi, Javier, Nori, Agustina, Novillo, Ojeda, Agustina A., Oklander, Luciana I., Orozco, María M., Ramiro, Ovejero, Palmerio, Andrés G., Paso Viola, María N., Hernán, Pastore, Paszko, Lorena M., Pérez Carusi, Lorena C., Perovic, Pablo G., Alejandro, Perretta, Pozzi, Carla M., Ramírez-Chaves, Héctor E., Relva, María A., Reppucci, Juan I., Facundo, Robino, Rodríguez-Cabal, Mariano A., Rodríguez-Planes, Lucía I., Ignacio, Roesler, Rossi, Luis F., Valentina, Segura, Claudio, Sillero-Zubiri, Florencia, Sittoni, Andrés, Tálamo, Torres Monges, Julio C., Alejandro, Travaini, Túnez, Juan I., Udrizar Sauthier, Daniel E., Uhart, Marcela M., Urquizo, José H., Vargas, Oscar E., Wiemeyer, Guillermo M., Marina, Winter, Wolfenson, Laura I., and Ricardo, Ojeda

Subjects
General Agricultural and Biological Sciences
Published
2023
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5. Potential contributions of mammals to human well-being in Argentina

Author

Virginia Alonso Roldán, Micaela Camino, Antonella Argoitia, Claudia M. Campos, Nicolás Caruso, Elena B. Eder, Ricardo Baldi, Diego E. Birochio, Flavio M. Cappa, M. Victoria Lassaga, M. Luz Olmedo, Anahí Formoso, Valeria C. D'Agostino, Camila S. González Noschese, Daniel Udrizar Sauthier, Cecilia P. Juárez, Mariana Degrati, Martín Iglesias, Lorena Coelho, Ailín Sosa Drouville, and José W. Priotto

Subjects
Contribuciones de la Naturaleza a las Personas, servicios ecosistémicos, conservación, Ciencias Exactas y Naturales, Biodiversidad, funciones ecosistémicas
Abstract

Fil: Birochio, Diego Enrique. Universidad Nacional de Río Negro. Centro de Investigaciones y Transferencia de Río Negro. Río Negro; Argentina. Fil: Roldán, Virginia Alonso. Grupo de Investigación en Gestión Desarrollo Territorial y Ambiente (GesDTA), UTN Facultad Regional Chubut, Puerto Madryn, Chubut, Argentina. Fil: Camino, Micaela. EDGE, Sociedad Zoológica de Londres, Camden, Londres, Reino Unido. 5CECOAL-CONICET, Corrientes, Argentina Fil: Argoitia, Antonella. UNNE-CONICET, Corrientes, Argentina. Fil: Campos, Claudia M. Red de Ecología de Mamíferos de Tierras Secas. IADIZA (CONICET, UNCuyo, Gob. de Mendoza), Mendoza, Argentina Fil: Caruso, Nicolás. Grupo de Ecología Comportamental de Mamíferos, INBIOSUR-CONICET-UNS, Bahía Blanca, Argentina Fil: Eder, Elena B. Grupo de Estudios de Macroecología Marina (GEMMA), CESIMAR-CONICET, Puerto Madryn, Chubut, Argentina Fil: Baldi, Ricardo. Grupo de Estudio de Mamíferos Terrestres (GEMTE), IPEEC-CONICET, Puerto Madryn, Chubut, Argentina. Fil: Cappa, Flavio M. CIGEOBIO, UNSJ-CONICET, San Juan, Argentina Fil: Lassaga, M. Victoria. Natura International, Córdoba, Argentina. Fil: Olmedo, M. Luz. Programa de Conservación de los Murciélagos de Argentina (PCMA), Tucumán, Argentina Fil: Formoso, Anahí. Grupo de Estudio de Mamíferos Terrestres (GEMTE), IPEEC-CONICET, Puerto Madryn, Chubut, Argentina. Fil: D ́Agostino, Valeria C. Laboratorio de Mamíferos Marinos, CESIMAR- CONICET, Puerto Madryn, Chubut, Argentina. Fil: Udrizar Sauthier, Daniel. UNPSJB, Puerto Madryn, Chubut, Argentina. Fil: González Noschese, Camila S. Instituto de Investigaciones de Biodiversidad Argentina (PIDBA), UNT- CONICET, San Miguel de Tucumán, Argentina. Fil: Juárez, Cecilia P. Centro de Ecología y Biodiversidad del Chaco Argentino (CEBiCA), Facultad de Recursos Naturales, UNaF, Formosa, Argentina. Fil: Degrati, Mariana. Laboratorio de Mamíferos Marinos, CESIMAR- CONICET, Puerto Madryn, Chubut, Argentina. Fil: Iglesias, Martín. Grupo de Estudios sobre Biodiversidad en Agroecosistemas, Depto. BBE, FCEyN, UBA, CABA, Argentina. Fil: Coelho, Lorena. IIBCE, MEC, Uruguay. Fil: Drouville, Ailín Sosa. UNCO-Río Negro, Argentina. Fil: Priotto, José W. Grupo de Investigaciones en Ecología Poblacional y Comportamental (GIEPCO), Instituto de Ciencias de la Tierra, Biodiversidad y Ambiente (ICBIA), UNRC-CONICET, Río Cuarto, Córdoba, Argentina. Mammals are key components of biodiversity mediating ecosystem functions, mainly because ofthe diversity of forms and functions of this group. Understanding and making explicit the role of mammalsunderpinning Nature’s Contributions to People (NCP) or directly contributing to human well-being wouldhelp to in uence policy formulation towards sustainable development and nature conservation. Througha workshop held at the XXXII Jornadas Argentinas de Mastozoología and subsequent collaborative work,we compiled information related to Mammal’s Contributions to People in Argentina (MCP-Arg) based onparticipants’ interpretation of the available literature and their eld experience. Argentinian mammalscontribute to 12 of the 18 de ned NCPs. We derived numerous MCP-Arg from studies that focused mainly onecological processes and conservation, revealing an information gap in MCP-Arg description, quanti cation,and mapping. All taxa contribute similarly to the overall contributions, highlighting the importance ofpreserving mammal diversity. Conservation should also be framed at the local community rather thanregional scales, aiming to preserve ecological functioning and contributions to human well-being, especiallywithin regulation contributions. Our results show destructive feedback between threats and habitat-relatedcontributions, with habitat degradation being the greatest threat to mammalian contributions and habitatmaintenance the most threatened one. Our research indicates that a substantial amount of knowledge about MCP-Arg is available through narratives and interpretations. Considering the NCP approach to mammalia Considering the NCP approach to mammalian research, we can make signi cant contributions to both mammal conservation and human well-being RESUMEN.CONTRIBUCIONES POTENCIALES AL BIENESTAR HUMANO DE LOS MAMÍFEROSEN ARGENTINA. Debido a su diversidad de formas y funciones, los mamíferos son componentes clave dela biodiversidad y cumplen importantes funciones ecosistémicas. Para formular políticas que permitan undesarrollo sostenible y la conservación de la naturaleza, es fundamental comprender y explicitar el papel de losmamíferos en sustentar las Contribuciones de la Naturaleza a las Personas (CNP). Durante un taller realizadoen las XXXII Jornadas Argentinas de Mastozoología y un posterior estudio colaborativo, hemos recopiladoinformación relacionada con las CNP de mamíferos en Argentina (CMP-Arg) en base a la interpretaciónde la literatura disponible y la experiencia de campo. En la Argentina, los mamíferos contribuyen en 12 delas 18 CNP de nidas. Deducimos numerosas CMP-Arg de estudios centrados principalmente en procesosecológicos y de conservación, que muestran un vacío de información en cuanto a descripción, cuanti cación ymapeo de CMP-Arg. Todos los taxones realizan aportes similares a las contribuciones totales, lo que destaca laimportancia de preservar la diversidad de mamíferos. Los esfuerzos de conservación deben enmarcarse no soloa escala regional, sino también a escala local, con el objetivo de preservar las CNP. Nuestros resultados hanmostrado una asociación entre amenazas y contribuciones relacionadas con el hábitat: la degradación de esteha sido la principal amenaza para las contribuciones y su mantenimiento la contribución más amenazada.Nuestra investigación muestra que una cantidad importante de conocimiento sobre CMP-Arg está disponiblea través de narrativas y representaciones sociales. Mediante la implementación del enfoque del CNP enla investigación mastozoológica, podemos hacer aportes signi cativos tanto para la conservación de losmamíferos como para el bienestar humano.

Published
2022
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6. Categorización de los mamíferos de Argentina 2019: resumen y análisis de las amenazas

Author

Agustín M. Abba, Diego Varela, Sebastián Cirignoli, Javier A. Pereira, María Luisa Bolkovic, Silvana Peker, Gustavo M. Porini, Soledad de Bustos, Mariana Degrati, Pablo Denuncio, M. Mónica Díaz, Isabel E. Gómez Villafañe, M. Florencia Grandi, Martín M. Kowalewski, Rocío Loizaga de Castro, Gabriel Martin, Matías S. Mora, Javier Negrete, Mariela Nieves, Agustina A. Ojeda, Rocío Palacios, Agustín J. Paviolo, Mariano S. Sánchez, Mariella Superina, Pablo Teta, M. Laura Guichón, Alejandro E.J. Valenzuela, Marcelo F. Tognelli, and Ricardo A. Ojeda

Published
2022
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8. Seasonal variation and group size affect movement patterns of two pelagic dolphin species (Lagenorhynchus obscurus and Delphinus delphis)

Author

Silvana Laura Dans, Elvio Agustin Luzenti, Mariano Alberto Coscarella, Rocio Joo, Mariana Degrati, and Nadia Soledad Curcio

Subjects
Multidisciplinary, Dolphins, Common Dolphins, Climate, Fisheries, Fishes, Animals, Seasons
Abstract

Movement is a key factor in the survival and reproduction of most organisms with important links to bioenergetics and population dynamics. Animals use movement strategies that minimize the costs of locating resources, maximizing energy gains. Effectiveness of these strategies depends on the spatial distribution, variability and predictability of resources. The study of fine-scale movement of small cetaceans in the pelagic domain is limited, in part because of the logistical difficulties associated with tagging and tracking them. Here we describe and model the fine-scale movement patterns of two pelagic dolphin species using georeferenced movement and behavioral data obtained by tracking dolphin groups on board small vessels. Movement patterns differed by species, group sizes and seasons. Dusky dolphin groups moved shorter distances when feeding and longer distances when traveling whereas the common dolphin did the same only when they moved in large groups. In summer, both dolphins cover longer distances in a more linear path, while in winter the movement is more erratic and moving shorter distances. Both species of dolphins prey on small pelagic fishes, which are patchily distributed and show seasonal variability in school sizes and distribution. However, dusky dolphins rely on anchovy to a larger extent than common dolphins. In Nuevo Gulf, anchovy shoals are smaller and separated by shorter distances in winter and dusky dolphins´ movement pattern is consistent with this. Dusky and common dolphins are impacted by tourism and fisheries. Further modelling of movement could be inform spatial based management tools.

Published
2022

9. Physical and biological drivers of pelagic fish distribution at high spatial resolution in two Patagonian Gulfs

Author

Elvio Agustín Luzenti, Guillermo Svendsen, Raúl González, Mariana Degrati, Silvana Laura Dans, and Nadia Soledad Curcio

Subjects
Squat lobster, biology, business.industry, Distribution (economics), Pelagic zone, Aquatic Science, Oceanography, biology.organism_classification, Geography, Remote sensing (archaeology), Anchovy, High spatial resolution, business
Abstract

Fil: Luzenti, Elvio Agustin. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Centro Nacional Patagonico. Centro para el Estudio de Sistemas Marinos; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina

Published
2021
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10. Lejos de casa: nuevo registro para delfines comunes de pico corto, Delphinus delphis (Cetacea, Odontoceti, Delphinidae), en Bahía Camarones, Patagonia, República Argentina

Author

Mariana Degrati, Cristian Alberto Durante, and Rocio Loizaga de Castro

Subjects
purl.org/becyt/ford/1 [https], ATLÁNTICO SUROCCIDENTAL, DELFÍN COMÚN DE PICO CORTO, EXTENSIÓN DE RANGO, DISTRIBUCIÓN, purl.org/becyt/ford/1.6 [https]
Abstract

El delfín común de pico corto, Delphinus delphis (Linnaeus, 1758), es un pequeño cetáceo con distribución en aguas tropicales y subtropicales. En el presente trabajo se reporta un nuevo registro de delfines comunes de pico corto en el área de Bahía Camarones, Patagonia, República Argentina. El pequeño grupo de delfines estaba formado por tres individuos adultos y un individuo más pequeño, probablemente juvenil. Este evento de avistamiento constituye el registro más meridional de la especie en la costa argentina, destacándose aquí la importancia de los monitoreos sistemáticos como parte integral de cualquier programa destinado a promover el bienestar de las comunidades locales de cetáceos. The short-beaked common dolphin, Delphinus delphis (Linnaeus, 1758), is a pelagic small cetacean distributed in tropical and subtropical waters. Here we present a new record for short-beaked common dolphins in Bahía Camarones, Patagonia, Argentina. The small group of dolphins was formed by three adult individuals and a smaller one, probably a juvenile. This sighting event is the southernmost record for the species in the Argentine coast, showing the importance of systematic surveys as an integral part of any program aimed at monitoring the well-being of local cetacean communities. Fil: Loizaga de Castro, Rocio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Durante, Cristian Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Degrati, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina

Published
2020
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11. Potential endocrine correlation with exposure to domoic acid in Southern Right Whale (Eubalaena australis) at the Península Valdés breeding ground

Author

Valeria C, D'Agostino, Alejandro, Fernández Ajó, Mariana, Degrati, Bernd, Krock, Kathleen E, Hunt, Marcela M, Uhart, and C Loren, Buck

Subjects
Kainic Acid, Whales, Animals, Lactation, Female, Seasons
Abstract

In waters off Península Valdés (PV), Argentina, southern right whales (SRW, Eubalaena australis) are occasionally exposed to domoic acid (DA), a neurotoxin produced by diatoms of the genus Pseudo-nitzschia. Domoic acid toxicity in marine mammals can cause gastrointestinal and neurological clinical signs, alterations in hematologic and endocrine variables, and can be fatal in extreme cases. In this study, we validated an enzyme immunoassay to quantify fecal glucocorticoid metabolites (fGCm) in 16 SRW fecal samples from live and dead stranded whales in PV from 2013 to 2018 and assessed fGCm levels associated with DA exposure. Overall, fGCm levels were significantly lower in SRWs with detectable fecal DA (n = 3) as compared to SRWs with undetectable fecal DA levels (n = 13). The highest fecal DA was observed in a live lactating female, which had low fGCm compared to the other lactating females studied. The highest fGCm was observed in a lactating female with undetectable DA; interestingly, at the time of sample collection, this female was sighted with two calves, an extremely unusual occurrence in this species. Though the sample size of these exceptionally rare breeding-season fecal samples was unavoidably small, our study provides evidence of potential adrenal alterations in whales exposed to an environmental neurotoxin such as DA.

Published
2021

12. Morphology of the mandibular gnathobases of the copepods Calanus australis and Calanoides carinatus: Evidence of omnivory

Author

Monica Susana Hoffmeyer, Mariana Degrati, and Valeria Carina D'agostino

Subjects
0106 biological sciences, CALANOID COPEPODS, CALANUS AUSTRALIS, 010607 zoology, Zoology, Morphology (biology), Biology, OMNIVOROUS, 010603 evolutionary biology, 01 natural sciences, Ciencias Biológicas, CALANOIDES CARINATUS, Calanus australis, Calanoides carinatus, Animal Science and Zoology, Otros Tópicos Biológicos, NORTHERN PATAGONIAN GULFS, MANDIBULAR GNATHOBASES, CIENCIAS NATURALES Y EXACTAS
Abstract

In spite of the worldwide ecological relevance of Calanus australis and Calanoides carinatus, little is known on the morphology of their mandibular gnathobase edges (MGEs). Thus, in order to further learn about the relationship between MGEs and diet, adults and copepodites of C. australis and C. carinatus collected from northern Patagonian coasts, Argentina, were morphologically analyzed using confocal laser scanning microscopy in transmission mode and scanning electron microscopy. In C. australis males as well as in C. australis and C. carinatus females, MGEs were found to end in one dorsal seta and to have one ventral tooth, four central teeth and three dorsal teeth. In contrast, in C. carinatus males, MGEs were observed to be rudimentary and with no dorsal seta, and −contrary to published data− they were found to have three cone-shaped, short and small tooth-like structures and three-four tooth-like structures that were long and pointed. The main differences between MGEs from copepodites and adults of C. australis and C. carinatus females lied in the number of cuspids observed on the different teeth and the presence of a short inner lateral peak found only in C. australis ventral tooth. Overall, the evidence gathered from our study leads us to classify C. australis and C. carinatus as omnivores. Fil: D'Agostino, Valeria C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Hoffmeyer, Mónica S.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Tecnológica Nacional. Facultad Regional Bahía Blanca; Argentina Fil: Degrati, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina

Published
2020

13. Dusky dolphin group dynamics and association patterns in Península Valdés, Argentina

Author

Silvana Laura Dans, Mariano Alberto Coscarella, Enrique Alberto Crespo, and Mariana Degrati

Subjects
0106 biological sciences, geography.geographical_feature_category, biology, 010604 marine biology & hydrobiology, DUSKY DOLPHIN, LAGENORHYNCHUS OBSCURUS, SOCIAL STRUCTURE, Ecología, Aquatic Science, Group dynamic, biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, PREY AVAILABILITY, Ciencias Biológicas, Geography, Peninsula, GROUPS DYNAMICS, Dusky dolphin, Humanities, CIENCIAS NATURALES Y EXACTAS, Ecology, Evolution, Behavior and Systematics
Abstract

We inspected dusky dolphin (Lagenorhynchus obscurus) group dynamics in Golfo Nuevo and found differences in social organization between cold and warm seasons. Surveys were conducted onboard a research vessel, from which we collected behavioral observations and group fission-fusion data from 2001 to 2008; we also collected photo-identification data from 2004 to 2012. To analyze association patterns, we calculated half-weight association index (HWI) and social differentiation (S). We conducted a Monte Carlo permutation test to determine whether observed association patterns were significantly different from random association using a compiled version of SOCPROG 2.7. Group fission and fusion dynamics depended on group behavior, the main activity after the groups' fusion was feeding, and they never fission before socializing. The social structure of dusky dolphins included long-term preferred companions in the cold season; during the warm season, there were no preferred companions. This seasonal difference in social structure could be related to an accompanying shift in foraging behaviors that appears to be driven by changes in prey availability. If so, then a loosening of bonds among individuals during the warm season, when prey is more available, would reflect these social structure changes. Fil: Degrati, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina Fil: Coscarella, Mariano Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina Fil: Crespo, Enrique Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina Fil: Dans, Silvana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina

Published
2018
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14. The southwestern Atlantic southern right whale,Eubalaena australis, population is growing but at a decelerated rate

Author

Enrique Alberto Crespo, Silvana Laura Dans, Mariano Alberto Coscarella, Guillermo Svendsen, Susana N. Pedraza, and Mariana Degrati

Subjects
0106 biological sciences, education.field_of_study, biology, Eubalaena australis, 010604 marine biology & hydrobiology, Population, Aquatic Science, biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, Rate of increase, Fishery, Geography, Right whale, education, Ecology, Evolution, Behavior and Systematics
Abstract

Fil: Crespo, Enrique Alberto. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Centro Nacional Patagonico. Centro para el Estudio de Sistemas Marinos; Argentina

Published
2018
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15. The seasonal dynamics of plankton communities relative to the foraging of the southern right whale ( Eubalaena australis ) in northern Patagonian gulfs, Península Valdés, Argentina

Author

Norma Santinelli, Mariana Degrati, Valeria Carina D'agostino, Viviana Sastre, Monica Susana Hoffmeyer, and Silvana Laura Dans

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, Eubalaena australis, Foraging, NORTH PATAGONIAN GULFS, Aquatic Science, Oceanography, MESOZOOPLANKTON, 01 natural sciences, Ciencias Biológicas, Peninsula, PHYTOPLANKTON, Phytoplankton, medicine, 0105 earth and related environmental sciences, geography.geographical_feature_category, biology, Ecology, 010604 marine biology & hydrobiology, Community structure, Geology, Ecología, Seasonality, Plankton, biology.organism_classification, medicine.disease, SEASONALITY, Geography, Right whale, COMMUNITY STRUCTURE, SOUTHERN RIGHT WHALE, CIENCIAS NATURALES Y EXACTAS
Abstract

This is the first exploratory study that addresses simultaneously the phytoplankton and mesozooplankton seasonal dynamics associated with some environmental factors in the northern Patagonian gulfs: Golfo Nuevo (GN) and Golfo San José GSJ), Argentina, during an annual cycle (December 2014–2015 and January 2015–2016, respectively). It also reports data on mesozooplankton composition and abundance in a sample collected while southern right whales (Eubalaena australis) were feeding at the sea surface in Bahía Pirámide (GN). The phytoplankton community was represented by 69 taxa in GN and by 83 taxa in GSJ. In GN, phytoplankton was mainly dominated by diatoms and dinoflagellates whereas in GSJ diatoms dominated the phytoplankton community throughout the year. In GN, the highest phytoplankton biomass and density values were registered during austral spring, 2015 which coincided with a Pseudo-nitzschia australis bloom. In contrast, the lowest biomass values, which were associated with elevated abundances of dinoflagellates, were observed in late spring 2014. In GSJ, the highest biomass values showed two equal peaks in austral autumn and spring 2015. The latter was associated with the maximum cell density recorded in this gulf during a Chaetoceros debilis bloom. In contrast, the lowest biomass values were recorded in winter 2015. Mesozooplankton was represented by 63 taxa in GN and by 61 taxa in GSJ. In GN, this community was mainly represented by cladocerans and copepods, whereas it was dominated by copepods in GSJ. The lowest mesozooplankton abundances were recorded in austral winter in both gulfs. In GN, the highest abundances were recorded in austral summer and spring 2015, whereas in GSJ, the maximum mesozooplankton abundances were observed during austral summer and autumn 2015. The major prey items for E. australis were the copepods Calanoides carinatus, Ctenocalanus vanus, Calanus australis, and Paracalanus parvus, zoeae of the squat lobster Munida gregaria, calyptopis and furcilia of Euphausia lucens, and fish eggs and larvae. In both gulfs, the warm seasons were mainly characterized by higher relative abundances of diatoms, while the cold seasons were mostly associated with higher abundances of dinoflagellates and Dictyochophyceae. Salinity and phaeopigments were related with copepod and appendicularian abundances, whereas surface sea water temperature seemed to modulate the seasonal distribution pattern of cladocerans and decapods. Fil: D'agostino, Valeria Carina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Degrati, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Santinelli, Norma Herminia. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Trelew; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Sastre, Alicia Viviana. Universidad Nacional de la Patagonia "San Juan Bosco". Facultad de Ciencias Naturales - Sede Trelew; Argentina Fil: Dans, Silvana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Hoffmeyer, Monica Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Tecnológica Nacional. Facultad Regional Bahía Blanca; Argentina

Published
2018
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22. Occurrence of Toxigenic Microalgal Species and Phycotoxin Accumulation in Mesozooplankton in Northern Patagonian Gulfs, Argentina

Author

Torben Krohn, Norma Santinelli, Monica Susana Hoffmeyer, Viviana Sastre, Mariana Degrati, Bernd Krock, and Valeria Carina D'agostino

Subjects
0106 biological sciences, 010504 meteorology & atmospheric sciences, Health, Toxicology and Mutagenesis, Argentina, Biology, 01 natural sciences, Algal bloom, Zooplankton, Ciencias Biológicas, purl.org/becyt/ford/1 [https], TOXIGENIC PHYTOPLANKTON, Microalgae, Environmental Chemistry, Animals, Seawater, 14. Life underwater, NORTHERN PATAGONIAN GULFS, Biomass, purl.org/becyt/ford/1.6 [https], 0105 earth and related environmental sciences, PHYCOTOXINS, Diatoms, Phycotoxin, Kainic Acid, Geography, Ecology, 010604 marine biology & hydrobiology, PHYCOTOXIN TROPHIC TRANSFER, Ecología, MESOZOOPLANKTON ACCUMULATION, Phytoplankton, HARMFUL ALGAL BLOOMS, Dinoflagellida, Marine Toxins, Adsorption, Seasons, CIENCIAS NATURALES Y EXACTAS
Abstract

In the Northern Patagonian gulfs of Argentina (Golfo Nuevo and Golfo San José), blooms of toxigenic microalgae and the detection of their associated phycotoxins are recurrent phenomena. The present study evaluated the transfer of phycotoxins from toxigenic microalgae to mesozooplankton in Golfo Nuevo and Golfo San José throughout an annual cycle (December 2014–2015 and January 2015–2016, respectively). In addition, solid‐phase adsorption toxin tracking (SPATT) samplers were deployed for the first time in these gulfs, to estimate the occurrence of phycotoxins in the seawater between the phytoplankton samplings. Domoic acid was present throughout the annual cycle in SPATT samplers, whereas no paralytic shellfish poisoning toxins were detected. Ten toxigenic species were identified: Alexandrium catenella, Dinophysis acuminata, Dinophysis acuta, Dinophysis tripos, Dinophysis caudata, Prorocentrum lima, Pseudo‐nitzschia australis, Pseudo‐nitzschia calliantha, Pseudo‐nitzschia fraudulenta, and Pseudo‐nitzschia pungens. Lipophilic and hydrophilic toxins were detected in phytoplankton and mesozooplankton from both gulfs. Pseudo‐nitzschia spp. were the toxigenic species most frequent in these gulfs. Consequently, domoic acid was the phycotoxin most abundantly detected and transferred to upper trophic levels. Spirolides were detected in phytoplankton and mesozooplankton for the first time in the study area. Likewise, dinophysistoxins were found in mesozooplankton from both gulfs, and this is the first report of the presence of these phycotoxins in zooplankton from the Argentine Sea. The dominance of calanoid copepods indicates that they were the primary vector of phycotoxins in the pelagic trophic web. Fil: D'Agostino, Valeria C.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Krock, Bernd. Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung; Alemania Fil: Degrati, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina Fil: Sastre, Viviana. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina Fil: Santinelli, Norma Herminia. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina Fil: Krohn, Torben. Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung; Alemania Fil: Hoffmeyer, Mónica S.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Tecnológica Nacional. Facultad Regional Bahía Blanca; Argentina

Published
2019

23. Nonreproductive Sexual Behavior in Baleen Whales: Sexual Harassment by an Adult Male on a Calf in Southern Right Whales (Eubalaena australis)

Author

Juan M. Goity, Alexis Fioramonti, Mariana Degrati, Valeria Carina D'agostino, Cristian Campos, and Fernando Varsky

Subjects
050103 clinical psychology, 030505 public health, Adult male, biology, Eubalaena australis, Otras Ciencias Biológicas, 05 social sciences, EUBALAENA AUSTRALIS, Aquatic Science, biology.organism_classification, Ciencias Biológicas, Fishery, 03 medical and health sciences, Baleen, SEXUAL HARASSMENT, Sexual behavior, ADULT MALE, NONREPRODUCTIVE SEXUAL BEHAVIOR, Harassment, 0501 psychology and cognitive sciences, Animal Science and Zoology, 0305 other medical science, CIENCIAS NATURALES Y EXACTAS, Nature and Landscape Conservation
Abstract

We describe a sexual harassment by an adult male southern right whale to a conspecific calf while on the calving and mating grounds near PV. Sexual harassment is defined in this paper as the behavior of an adult male pursuing a calf with apparent intention to copulate. Observations were made opportunistically from the whale-watching motor vessel. The southern right whale group included a mother calf pair and a solitary individual second adult. The second adult seemed to be chasing the calf which was swimming rapidly on its left side at 5 m average distance from the second adult / pursuing whale. while the calf was positioned above the second adult, this second adult introduced his penis into the calf?s genital slit (see supplementary online underwater video S1).Copulation attempts between an adult male baleen whale and a calf has not been previously reported in the literature. The observations described here indicate that nonreproductive copulation attempts between a southern right whale adult male and a conspecific calf occurred near PV in the calving and mating grounds. Fil: D'agostino, Valeria Carina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina Fil: Fioramonti, Alexis. Proyecto Patagonia Documental; Argentina Fil: Varsky, Fernando. Proyecto Patagonia Documental; Argentina Fil: Campos, Cristian. Proyecto Patagonia Documental; Argentina Fil: Goity, Juan M.. Whales Argentina; Argentina Fil: Degrati, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Centro para el Estudio de Sistemas Marinos; Argentina. Universidad Nacional de la Patagonia; Argentina

Published
2017
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24. Framing and communicating southern right whale – kelp gull biological interaction in Peninsula Valdés, Argentina: The effects of attribute frames on human’s perceptions and decision-making policies

Author

Mariana Degrati, Virginia Mailen Tortolini, and Mariano Alberto Coscarella

Subjects
0106 biological sciences, Economics and Econometrics, media_common.quotation_subject, Management, Monitoring, Policy and Law, Aquatic Science, Public domain, 01 natural sciences, Peninsula, biology.animal, Perception, General Environmental Science, media_common, geography.geographical_feature_category, biology, Whale, business.industry, 010604 marine biology & hydrobiology, 04 agricultural and veterinary sciences, biology.organism_classification, Geography, Environmental education, Framing (social sciences), 040102 fisheries, 0401 agriculture, forestry, and fisheries, Whale watching, business, Right whale, Law, Social psychology
Abstract

Southern right whale-kelp gull biological interaction has been the focus of debates in Peninsula Valdes, Argentina, not only within the academia but also in the public domain. This interaction is perceived as an important and imminent threat to whale conservation and thus to the whale watching activity. When stakeholders complain, sometimes the management actions are not necessarily based on reality itself, but how reality is perceived. The contrasting perceptions of the biological interaction reflect differences in the frames that shape how individuals and institutions conceptualize the relevant aspects of this issue. This study compares the relative impact of attribute frames on tourists' attitudes and perceptions concerning interaction effects on whales, examining how frames could be used to shape decision strategies for management. Results from 100 interviews revealed that gender and attribute frames affected tourists' perception of interaction effect and damage. Greater perception of damage and more negative effects perception were found among women who had received the negative frame. Television, radio and whale watching at Puerto Piramide are the main sources from which the “kelp gulls produce damage to whales” information is gathered (57.15%). Tourists are less interested in gulls than in whales and present a positive attitude towards gulls. These results offer new insights for resource managers and policymakers and highlight the need of the use of the frame theory in delivering information as a part of any policy. The use of positive frame adjusting exaggerated perceptions of the interaction, is recommended to promote environmental education and awareness.

Published
2021
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25. Faecal analysis of southern right whales (Eubalaena australis) in Península Valdés calving ground, Argentina: Calanus australis, a key prey species

Author

Mariana Degrati, Valeria Carina D'agostino, and Monica Susana Hoffmeyer

Subjects
0106 biological sciences, CALANUS AUSTRALIS, 010504 meteorology & atmospheric sciences, Eubalaena australis, Otras Ciencias Biológicas, NORTH PATAGONIAN GULFS, Ice calving, EUBALAENA AUSTRALIS, FEEDING, Aquatic Science, Biology, 01 natural sciences, Zooplankton, Predation, Ciencias Biológicas, COPEPOD, RIGHT WHALES, biology.animal, CALVING GROUND, 0105 earth and related environmental sciences, Trophic level, Ecology, Whale, 010604 marine biology & hydrobiology, Plankton, biology.organism_classification, PENÍNSULA VALDÉS, MANDIBULAR GNATHOBASES, CIENCIAS NATURALES Y EXACTAS, Copepod
Abstract

Península Valdés (PV) is the most austral calving ground for the SW Atlantic population of Eubalaena australis. Recent studies indicate that E. australis often feeds in PV mainly in late September and October. A microscopic analysis of food chitin remains found in five whale faeces was performed in the present study in an attempt to obtain baseline knowledge about trophic ecology and degree of use of plankton food available for whales in PV during spring (September-December). The remains in faeces from stranded and live individuals included copepods, other zooplankton and centric diatoms, all of which were characterized. Copepod remains were found to be dominant. Scanning electron and confocal laser scanning microscopes were used for comparative analyses between the mandibular gnathobases found in whale faeces and those obtained from preserved specimens. Mandibular gnathobases were the same in structure and morphometry as those obtained from preserved Calanus australis (copepodites 4-6). The positive relationship observed between the total length and width of the mandibular gnathobases edge of C. australis and those found in faeces allowed us to infer the developmental stages of the copepods ingested by E. australis. Our results indicate - for the first time - the relevant role of C. australis copepodite 5 as main prey for E. australis in PV during the calving season. Copepodite 5 of C. australis accumulates energy-rich lipids. This is energetically attractive for whales and it is the potential reason why E. australis feeds mainly on dense patches dominated by this developmental stage of C. australis. Fil: D'agostino, Valeria Carina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina Fil: Hoffmeyer, Monica Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Tecnológica Nacional. Facultad Regional Bahía Blanca; Argentina Fil: Degrati, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia; Argentina

Published
2015
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26. Short Note: Technique Used by Killer Whales (Orcinus orca) When Hunting for Dolphins in Patagonia, Argentina

Author

Marisa Berzano, Mariana Degrati, María Leoní Gaffet, Gabriela Bellazzi, and Mariano Alberto Coscarella

Subjects
Fishery, Geography, Animal Science and Zoology, Aquatic Science, Nature and Landscape Conservation
Abstract

Fil: Coscarella, Mariano Alberto. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Nacional Patagonico; Argentina. Universidad Nacional de la Patagonia; Argentina

Published
2015
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27. Effects of Tour Boats on Dolphin Activity Examined with Sensitivity Analysis of Markov Chains

Author

Enrique Alberto Crespo, Mariana Degrati, Susana N. Pedraza, and Silvana Laura Dans

Subjects
Ecology, Political science, Humanities, Ecology, Evolution, Behavior and Systematics, Nature and Landscape Conservation
Abstract

Fil: Dans, Silvana Laura. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Nacional Patagonico; Argentina. Universidad Nacional de la Patagonia; Argentina

Published
2012
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28. Diving for food: a switch of foraging strategy of dusky dolphins in Argentina

Author

Silvana Laura Dans, Enrique Alberto Crespo, Mariana Degrati, and Griselda Valeria Garaffo

Subjects
biology, Ecology, Otras Ciencias Biológicas, Foraging, Zoology, biology.organism_classification, DUSKY DOLPHINS, Ciencias Biológicas, PATAGONIA, BEHAVIORAL SEQUENCES, Diving (activity), Abundance (ecology), Animal ecology, DIVING, Animal Science and Zoology, Lagenorhynchus, FORAGING STRATEGY, Transect, human activities, CIENCIAS NATURALES Y EXACTAS, Ecology, Evolution, Behavior and Systematics
Abstract

During winter, dusky dolphins (Lagenorhynchus obscurus) were observed in coordinated diving apparently in a feeding activity, contrasting with the surface feeding observed during summer. The aim of this work consisted in analyzing the diving activity as an alternative foraging strategy in Argentine dusky dolphins, based on sequential analysis. The study area was Golfo Nuevo, located in Northern Patagonia, Argentina. Random transects were surveyed by a research boat from 2001 to 2007. During behavioral sampling, group members were observed continuously and the predominant activity was recorded at 2-min intervals. Six predominant activities were identified. Each 2-min interval was classified according to the activity at the previous interval (preceding activity), the activity at the interval (following activity), and the season (cold or warm). Z scores were calculated and then used to construct sequence diagrams. An association between diving and milling behavior was observed. This could be another foraging tactics different to the surface foraging sequences and this could be related with the distribution or abundance of preys. Fil: Degrati, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia. Facultad de Ciencias Naturales. Sede Puerto Madryn; Argentina Fil: Dans, Silvana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia. Facultad de Ciencias Naturales. Sede Puerto Madryn; Argentina Fil: Garaffo, Griselda Valeria. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Crespo, Enrique Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia. Facultad de Ciencias Naturales. Sede Puerto Madryn; Argentina

Published
2012
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29. Dusky dolphin: modeling habitat selection

Author

Griselda Valeria Garaffo, Mariana Degrati, Paula Giudici, Enrique Alberto Crespo, Domingo A. Gagliardini, and Silvana Laura Dans

Subjects
Shore, Generalized linear model, geography, geography.geographical_feature_category, biology, Ecology, Cetacea, biology.organism_classification, Fishery, Habitat, Genetics, Dusky dolphin, Lagenorhynchus, Wildlife management, Animal Science and Zoology, Transect, Ecology, Evolution, Behavior and Systematics, Nature and Landscape Conservation
Abstract

The use of habitat selection models to predict the likely occurrence of wild populations is an important tool in conservation planning and wildlife management. The goal of our study was to build habitat selection models for the dusky dolphin (Lagenorhynchus obscurus) in Golfo Nuevo, Argentina. Random transects were surveyed by boat in 2002–2007. A grid of 1.5 × 1.5-km squares (cells) was constructed for the study area. We characterized each cell by depth, slope, distance from shore, sea-surface temperature, concentration of chlorophyll a, presence–absence of dolphins, and a coefficient of use by dusky dolphins. Models were developed for warm and cold seasons and for all data combined. Data collected during 2002–2005 were pooled to develop the model, and data collected during 2006–2007 were used for cross-validation. Logistic regression with a binomial error structure and a logit-link function were used to relate the presence of dolphins to habitat variables. Models with gamma structure and log-li...

Published
2010
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30. Dusky dolphin and tourist interaction: effect on diurnal feeding behavior

Author

Griselda Valeria Garaffo, Enrique A. Crespo, Mariana Degrati, Susana N. Pedraza, and Silvana Laura Dans

Subjects
Ecology, Group tracking, Aquatic Science, Biology, Interaction, biology.organism_classification, Predation, Research vessel, Fishery, Feeding behavior, Dusky dolphin, Marine ecosystem, human activities, Ecology, Evolution, Behavior and Systematics
Abstract

Dolphin watching is a relatively newly developed tourist activity. Although it is assumed to contribute to the conservation of marine ecosystems, its long-term adverse effects are still unknown. The present work aims to assess the impact of tour vessels on the behavior pattern of dusky dolphins displaying diurnal and cooperative feeding. We evaluated potential bias of commercial ves- sels to specific activities, short-term responses of dolphins to vessel approach, and longer-term effects of these changes, particularly on the activity budget and the time dolphins need to resume an activ- ity. Several field experiments were carried out in which dolphins were approached by a research ves- sel or by commercial vessels. Group tracking was also made from a research vessel. Behavioral sequences were modeled by stochastic matrix models. Activity budget and time to return to an activ- ity were obtained from matrix properties. Commercial trips found mostly feeding groups. Feeding showed the highest rate of change at the moment of vessel approach, and commercial vessels had an effect on the direction of change. Over the longer term, feeding and socializing time budgets decreased when commercial vessels were present. The time to return to feeding as well as the time it took for a group of dolphins to feed increased in the presence of commercial vessels. Dusky dol- phins in South Atlantic waters feed during the day on patchily distributed prey. Our study demon- strates that boat presence negatively affects the longer-term feeding efficiency of dusky dolphins.

Published
2008
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31. Habitat use by dusky dolphin in patagonia: how predictable is their location?

Author

Griselda Valeria Garaffo, Enrique Alberto Crespo, Silvana Laura Dans, Susana N. Pedraza, and Mariana Degrati

Subjects
Shore, geography, geography.geographical_feature_category, Ecology, biology, Cetacea, Aquatic Science, biology.organism_classification, Substrate (marine biology), Seafloor spreading, Oceanography, Habitat, Dusky dolphin, Transect, human activities, Bay, Ecology, Evolution, Behavior and Systematics
Abstract

Off Patagonian coasts, Argentina, the dusky dolphin is one of the most common small cetaceans. This species is the aim of newly developed watching activities during summer in Golfo Nuevo. However, the real occurrence and movement pattern are unknown. The objectives of this work were to investigate the predictability of dusky dolphin distribution, group structure and behaviour in the western portion of Golfo Nuevo, with respect to environmental features (bottom depth, bottom slope, distance from shore and substrate). Random transects in the bay were searched by small boat during the summer and autumn of 2001–2004. When a group of dolphins was sighted, estimates of group size, composition (mothers with calves, adults and juveniles only, and mixed groups) and the predominant activity (feeding, travelling, socialising, resting and milling) were recorded and thereafter at 2 min intervals. A grid of 1.5 × 1.5 km was constructed and each cell was characterised by environmental features, Area Use Index (percent of total annual search effort) and Activity Index (predominant behaviour of groups observed in that cell). Mothers with calves and smaller groups and resting behaviour occurred in shallowest waters supporting the idea/hypothesis that movement to shallower water is related to increased safety for individuals. Travelling occurred in the deepest areas with other behaviours observed in intermediate depths. Dolphin distribution within the bay differed significantly between years, but this was not related to any of the factors analysed in this study. Although there was considerable variation between years, in general, dolphins were found in deeper waters further from shore (except for mother–calf groups) and over areas with steeper seafloor gradient. The high variability in the distribution of the animals does not allow for the generation of a simple, area-specific management plan.

Published
2007
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32. Potentially toxic Pseudo-nitzschia species in plankton and fecal samples of Eubalaena australis from Península Valdés calving ground, Argentina

Author

Mariana Degrati, Valeria Carina D'agostino, Monica Susana Hoffmeyer, Gaston Osvaldo Almandoz, and Viviana Sastre

Subjects
Eubalaena australis, Otras Ciencias Biológicas, Ice calving, Aquatic Science, Oceanography, Ciencias Biológicas, purl.org/becyt/ford/1 [https], chemistry.chemical_compound, Phytoplankton, purl.org/becyt/ford/1.6 [https], Ecology, Evolution, Behavior and Systematics, Domoic Acid, Phycotoxin, biology, Ecology, Domoic acid, Eubalaena Australis, Plankton, biology.organism_classification, chemistry, Right Whales, Right whale, Pseudo-nitzschia, CIENCIAS NATURALES Y EXACTAS, Península Valdés, Pseudo-Nitzschia Blooms
Abstract

Península Valdés (PV) in Argentina is an important calving ground for the southern right whale Eubalaena australis. However, a high mortality of calves has been observed in the last years, which could be associated with phycotoxin exposure. During a sampling program conducted late in the calving seasons of 2004, 2005 and 2010, potentially toxic species of the genus Pseudo-nitzschia were observed to be an important component of the phytoplankton community and they were also found in fecal samples of two live whales and three stranded whales. In line with this, in the present study Pseudo-nitzschia australis, Pseudo-nitzschia fraudulenta, Pseudo-nitzschia pungens and the complex Pseudo-nitzschia pseudodelicatissima were identified in fecal samples and phytoplankton samples by light and electron microscopy. Although no toxin analysis was carried out in the present study, our findings suggest that E. australis could be exposed to domoic acid in their calving ground. Fil: D'agostino, Valeria Carina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentina Fil: Hoffmeyer, Monica Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Tecnológica Nacional. Facultad Regional Bahía Blanca; Argentina Fil: Almandoz, Gaston Osvaldo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Sastre, Viviana. Universidad Nacional de la Patagonia ; Argentina Fil: Degrati, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia. Facultad de Ciencias Naturales. Sede Puerto Madryn; Argentina

Published
2015

33. Seabird and dolphin associations: do seabirds benefit from feeding in association with dusky dolphins in Patagonia?

Author

Griselda Valeria Garaffo, Enrique Alberto Crespo, Mariana Degrati, and Silvana Laura Dans

Subjects
FEEDING ASSOCIATION, COMMENSALISM, biology, Ecology, PENINSULA VALDÉS, Zoología, Ornitología, Entomología, Etología, Aquatic Science, Commensalism, SEABIRD-CETACEAN INTERACTION, Ciencias Biológicas, Geography, biology.animal, Seabird, CIENCIAS NATURALES Y EXACTAS
Abstract

The objective of this study was to describe associations between several species of seabirds and dusky dolphins. We investigated during what dolphin activities seabirds were most commonly associated, and the size of flock in relation to the number of dolphins in a group. Since both seabirds and dolphins may display different feeding strategies, we also investigated if benefits differed among seabird species. Data were collected in Golfo Nuevo (42820′S, 65800′W) onboard a research vessel between 2001 and 2008. A total of 224 mixed groups of seabirds were encountered during this study. The seabird?dolphin associations were mainly observed during dusky dolphin surface feeding. Shearwaters and kelp gulls were mainly observed in flocks that were associated with dolphins, while Magellanic penguins and cormorants were mainly observed without dolphins. Seabirds may be conditioned to the foraging strategy of dolphins, since birds are associated with dolphins only during dolphin surface feeding. This association probably helped seabirds to find prey, but there were no obvious benefits to dolphins. Fil: Degrati, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina Fil: Dans, Silvana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina Fil: Garaffo, Griselda Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina Fil: Crespo, Enrique Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina

Published
2013

34. Sequential foraging of dusky dolphins with an inspection of their prey distribution

Author

Enrique Alberto Crespo, Silvana Laura Dans, Ariel G. Cabreira, Federico Castro Machado, Mariana Degrati, and Griselda Valeria Garaffo

Subjects
Ecology, business.industry, Foraging, FORAGING SEQUENCE, Distribution (economics), LAGENORHYNCHUS OBSCURUS, Biología Marina, Limnología, Aquatic Science, Biology, DUSKY DOLPHINS, Predation, Ciencias Biológicas, Fishery, PATAGONIA, ANCHOVIES, FORAGING STRATEGY, business, CIENCIAS NATURALES Y EXACTAS, Ecology, Evolution, Behavior and Systematics
Abstract

The aim of this work was to analyze the sequential foraging behavior of dusky dolphins (Lagenorhynchus obscurus). Foraging sequences were defined when more than two feeding bouts occur with a traveling bout between them. We hypothesized that traveling costs of searching for prey patches were related to the time spent feeding on a patch. In addition, the distribution and seasonal variation of anchovy schools were studied in the area to better understand dolphins’ behavior. We observed dolphins from a research vessel from 2001 to 2007, and recorded their location and behavior. Anchovy data were collected during two hydro-acoustic surveys. Dusky dolphin behaviors varied seasonally; they spent a greater proportion of time traveling and feeding in the warm season (Kruskal-Wallis: H = 172.07, P < 0.01). During the cold season dolphin groups were more likely to exhibit diving behavior and less surface feeding. We found a positive correlation between searching and foraging time (r = 0.88, P = 0.019), suggesting that the costs associated with searching were compensated by an increase in the energy intake during the foraging bout. There was an association between dusky dolphin and anchovy distribution, in that they co-varied spatially and seasonally. Fil: Degrati, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia; Argentina Fil: Dans, Silvana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia; Argentina Fil: Garaffo, Griselda Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentina Fil: Cabreira, Ariel Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina Fil: Castro Machado, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina Fil: Crespo, Enrique Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia; Argentina

Published
2012
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35. Effects of tour boats on dolphin activity examined with sensitivity analysis of Markov chains

Author

Silvana Laura, Dans, Mariana, Degrati, Susana Noemí, Pedraza, and Enrique Alberto, Crespo

Subjects
Conservation of Natural Resources, Time Factors, Behavior, Animal, Dolphins, Argentina, Feeding Behavior, Models, Biological, Sensitivity and Specificity, Markov Chains, Stress, Physiological, Animals, Humans, Human Activities, Ships
Abstract

In Patagonia, Argentina, watching dolphins, especially dusky dolphins (Lagenorhynchus obscurus), is a new tourist activity. Feeding time decreases and time to return to feeding after feeding is abandoned and time it takes a group of dolphins to feed increase in the presence of boats. Such effects on feeding behavior may exert energetic costs on dolphins and thus reduce an individual's survival and reproductive capacity or maybe associated with shifts in distribution. We sought to predict which behavioral changes modify the activity pattern of dolphins the most. We modeled behavioral sequences of dusky dolphins with Markov chains. We calculated transition probabilities from one activity to another and arranged them in a stochastic matrix model. The proportion of time dolphins dedicated to a given activity (activity budget) and the time it took a dolphin to resume that activity after it had been abandoned (recurrence time) were calculated. We used a sensitivity analysis of Markov chains to calculate the sensitivity of the time budget and the activity-resumption time to changes in behavioral transition probabilities. Feeding-time budget was most sensitive to changes in the probability of dolphins switching from traveling to feeding behavior and of maintaining feeding behavior. Thus, an increase in these probabilities would be associated with the largest reduction in the time dedicated to feeding. A reduction in the probability of changing from traveling to feeding would also be associated with the largest increases in the time it takes dolphins to resume feeding. To approach dolphins when they are traveling would not affect behavior less because presence of the boat may keep dolphins from returning to feeding. Our results may help operators of dolphin-watching vessels minimize negative effects on dolphins.

Published
2012

36. Modeling habitat use for dusky dolphin and Commerson's dolphin in Patagonia

Author

Griselda Valeria Garaffo, Enrique Alberto Crespo, Susana N. Pedraza, Mariana Degrati, Silvana Laura Dans, Raúl González, and Adrián Schiavini

Subjects
Aerial survey, Species distribution, Aquatic Science, Spearman's rank correlation coefficient, purl.org/becyt/ford/1 [https], Ciencias Biológicas, Cephalorhynchus, GENERALIZED LINEAR MODEL, DOLPHINS, Lagenorhynchus, HABITAT SELECTION, purl.org/becyt/ford/1.6 [https], Ecology, Evolution, Behavior and Systematics, geography.geographical_feature_category, Ecology, biology, Estuary, DISTRIBUTION MODELING, Biología Marina, Limnología, biology.organism_classification, Fishery, PATAGONIA, Geography, Habitat, Dusky dolphin, CIENCIAS NATURALES Y EXACTAS
Abstract

Several species of small cetaceans inhabit the coastal area of Patagonia (Argentina), but little is known about their distribution and the degree of overlap between them. The goal of the present study was to build habitat-selection models for small cetaceans in order to assess areas of particular importance for the different species. These models were constructed using physiographic and remotely sensed variables. From 1994 to 2007, 13 aerial surveys were conducted along the Patagonian coast (from Golfo San Matías: 40° 40'-42°14' S, 65° 00'-63°47' W to Bahía de los Nodales: 48°00' S, 65°35' W). A grid of 0.5° × 0.5° cells was constructed for the study area. Each cell was characterized by environmental variables and by the encounter rate (ER) for each cetacean species. The ER of each species was investigated in relation to environmental variables using generalized linear models, and model averaging (multimodel inference) was used to obtain a predicted ER for the different species. The correlation between the ER of different species was analyzed by Spearman rank correlation. The environmental variables that were found to be significant predictors of species distribution differed between species. The ERs of dusky dolphin Lagenorhynchus obscurus and Peale's dolphin L. australis showed a positive relationship. Commerson's dolphin Cephalorhynchus commersonii presented a more coastal distribution than the other species, and individuals were more often found feeding in estuarine zones. Knowledge of the patterns of distribution of small cetaceans along the Patagonian coast provides baseline knowledge of how these species interact with each other and their environment. Such information should be considered when managing potential areas of conflict between coastal small cetaceans and human activities. Fil: Garaffo, Griselda V.. Universidad Nacional de Mar del Plata; Argentina Fil: Dans, Silvana Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina Fil: Pedraza, Susana N.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina Fil: Degrati, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina Fil: Schiavini, Adrian Carlos Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Wildlife Conservation Society Argentina; Argentina Fil: González, Raul Alberto Candido. Universidad Nacional del Comahue. Instituto de Biología Marina y Pesquera Almirante Storni; Argentina Fil: Crespo, Enrique Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina

Published
2011

37. Diurnal behavior of dusky dolphins, Lagenorhynchus obscurus, in Golfo Nuevo, Argentina

Author

Enrique A. Crespo, Griselda Valeria Garaffo, Mariana Degrati, Susana N. Pedraza, and Silvana Laura Dans

Subjects
Zoology, Cetacea, LAGENORHYNCHUS OBSCURUS, Research vessel, Ciencias Biológicas, Genetics, medicine, Age composition, Daylight, Lagenorhynchus, ACTIVITY PATTERNS, Ecology, Evolution, Behavior and Systematics, Nature and Landscape Conservation, Ecology, biology, Aquatic animal, Seasonality, Ecología, biology.organism_classification, medicine.disease, DUSKY DOLPHINS, PATAGONIA, Dusky dolphin, Animal Science and Zoology, human activities, CIENCIAS NATURALES Y EXACTAS
Abstract

Las medidas estandardizadas del comportamiento pueden ser una poderosa herramienta para predecir los efectos de las actividades humanas sobre poblaciones naturales de mamíferos. Cuantificamos el presupuesto diario de la actividad de los delfines oscuros (Lagenorhynchus obscurus) en el Golfo Nuevo, Argentina, examinando los cambios de actividad en función de la estación y de los tipos de grupos. Las observaciones fueron hechas desde una embarcación de investigación durante el verano y el otoño desde 2001 hasta 2005. Se utilizó una metodología de seguimiento de grupo focal. La actividad predominante de cada grupo fue registrada usando un muestreo instantáneo, con intervalos de 2 minutos. La actividad mas frecuentemente observada fue el traslado, seguido por nado errático y alimentación. Las madres con cría invirtieron más tiempo en nado errático y descanso, mientras que grupos grandes de adultos y juveniles y los grupos mixtos invirtieron más tiempo en traslado y alimentación. Aunque se encontró un patrón estacional en cuanto al tamaño y la composición de los grupos, poca variación estacional fue encontrada en los presupuestos de la actividad, que fueron casi constantes durante las horas del día. Los resultados generados en este estudio proporcionan información de base para poder detectar diferencias en el comportamiento asociadas al turismo y otras actividades humanas en la región. Standardized measures of behavior can be powerful tools for predicting effects of human activities on natural populations of mammals. We quantified the diurnal activity budget of dusky dolphins (Lagenorhynchus obscurus) in Golfo Nuevo, Argentina, by examining variation in activity as a function of season and age composition of social groups. Observations were made from a research vessel during summer and autumn from 2001 to 2005. Focal group-follow methodology was used. The predominant activity in each social group was recorded using instantaneous sampling, with a 2-min interscan interval. The main daytime activity of dusky dolphins was traveling, followed by milling and feeding. Mother and calf pairs spent more time milling and resting, whereas larger groups of adults and juveniles as well as mixed-age-class groups spent more time traveling and feeding. Although a seasonal pattern of variation in group size and composition was found, little seasonal variation was found in activity budgets, which were almost constant during daylight hours. The activity budget generated by this study provides a baseline for detection of behavioral differences associated with tourism and other human activity in the region. Fil: Degrati, Mariana. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina Fil: Dans, Silvana Laura. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina Fil: Pedraza, Susana Noemi. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina Fil: Crespo, Enrique Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina Fil: Garaffo, Griselda Valeria. Universidad Nacional de la Patagonia "San Juan Bosco"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentina

Published
2008

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