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3. Bubble blasts! An adaptation for buoyancy regulation in shallow foraging gray whales.

Author

Bird, Clara N., Pirotta, Enrico, New, Leslie, Bierlich, K. C., Hildebrand, Lisa, Fernandez Ajó, Alejandro, and Torres, Leigh G.

Subjects
BALEEN whales, WHALE behavior, IDENTIFICATION of animals, WATER depth, BUOYANCY
Abstract

Foraging efficiency is key to animal fitness. Consequently, animals evolved a variety of kinematic, morphological, physiological, and behavioral adaptations for efficient locomotion to reduce energy expenditure while moving to find, capture, and consume prey. Often suited to specific habitat and prey types, these adaptations correspond to the terrain or substrate the animal moves through. In aquatic systems, adaptations focus on overcoming drag, buoyancy, and hydrostatic forces. Buoyancy both benefits and hinders diving animals; in particular, shallow divers constantly contend with the costs of overcoming buoyancy to dive and maintain position. Pacific Coast Feeding Group (PCFG) gray whales forage in shallow habitats where they work against buoyancy to dive and feed using various foraging tactics. Bubble blasts (underwater exhalations) have been observed during several foraging tactics performed by PCFG whales. As exhalations aid buoyancy regulation in other diving animals, we hypothesize that bubble blasts are performed by longer, more buoyant whales in shallower water and that bubble blasts increase dive duration while accounting for size and tactic. We test our hypotheses using Bayesian linear mixed effects models and a 7‐year dataset of drone footage containing concurrent individual morphological and behavioral data. We find that while headstanding – a stationary, head‐down tactic – bubble blasts are performed by longer, more buoyant whales and extend the dive duration, whereas whales using forward‐swimming tactics are less likely to bubble blast. Our results suggest that PCFG gray whales may use bubble blasts as a behavioral adaption to mitigate the cost of energetically expensive tactics in their shallow habitat foraging niche. [ABSTRACT FROM AUTHOR]

Published
2024
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4. Modeling individual growth reveals decreasing gray whale body length and correlations with ocean climate indices at multiple scales.

Author

Pirotta, Enrico, Bierlich, K. C., New, Leslie, Hildebrand, Lisa, Bird, Clara N., Fernandez Ajó, Alejandro, and Torres, Leigh G.

Subjects
BIOTIC communities, EFFECT of human beings on climate change, HOME range (Animal geography), BODY size, WHALES, LIFE history theory
Abstract

Changes in body size have been documented across taxa in response to human activities and climate change. Body size influences many aspects of an individual's physiology, behavior, and ecology, ultimately affecting life history performance and resilience to stressors. In this study, we developed an analytical approach to model individual growth patterns using aerial imagery collected via drones, which can be used to investigate shifts in body size in a population and the associated drivers. We applied the method to a large morphological dataset of gray whales (Eschrichtius robustus) using a distinct foraging ground along the NE Pacific coast, and found that the asymptotic length of these whales has declined since around the year 2000 at an average rate of 0.05–0.12 m/y. The decline has been stronger in females, which are estimated to be now comparable in size to males, minimizing sexual dimorphism. We show that the decline in asymptotic length is correlated with two oceanographic metrics acting as proxies of habitat quality at different scales: the mean Pacific Decadal Oscillation index, and the mean ratio between upwelling intensity in a season and the number of relaxation events. These results suggest that the decline in gray whale body size may represent a plastic response to changing environmental conditions. Decreasing body size could have cascading effects on the population's demography, ability to adjust to environmental changes, and ecological influence on the structure of their community. This finding adds to the mounting evidence that body size is shrinking in several marine populations in association with climate change and other anthropogenic stressors. Our modeling approach is broadly applicable across multiple systems where morphological data on megafauna are collected using drones. [ABSTRACT FROM AUTHOR]

Published
2024
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5. Assessment of a non-invasive approach to pregnancy diagnosis in gray whales through drone-based photogrammetry and faecal hormone analysis

Author

Fernandez Ajó, Alejandro, Pirotta, Enrico, Bierlich, K. C., Hildebrand, Lisa, Bird, Clara N., Hunt, Kathleen E., Buck, C. Loren, New, Leslie, Dillon, Danielle, Torres, Leigh G., and University of St Andrews. School of Biology

Subjects
MCP
Abstract

This project was supported by the NOAA National Marine Fisheries Service Office of Science and Technology, the Office of Naval Research Marine Mammals and Biology Program (no. N00014-20-1-2760), the Oregon State University Marine Mammal Institute and Oregon Sea Grant. Knowledge of baleen whales’ reproductive physiology is limited and requires long-term individual-based studies and innovative tools. We used 6 years of individual-level data on the Pacific Coast Feeding Group gray whales to evaluate the utility of faecal progesterone immunoassays and drone-based photogrammetry for pregnancy diagnosis. We explored the variability in faecal progesterone metabolites and body morphology relative to observed reproductive status and estimated the pregnancy probability for mature females of unknown reproductive status using normal mixture models. Individual females had higher faecal progesterone concentrations when pregnant than when presumed nonpregnant. Yet, at the population level, high overlap and variability in progesterone metabolite concentrations occurred between pregnant and non-pregnant groups, limiting this metric for accurate pregnancy diagnosis in gray whales. Alternatively, body width at 50% of the total body length (W50) correctly discriminated pregnant from non-pregnant females at individual and population levels, with high accuracy. Application of the model using W50 metric to mature females of unknown pregnancy status identified eight additional pregnancies with high confidence. Our findings highlight the utility of drone-based photogrammetry to non-invasively diagnose pregnancy in this group of gray whales, and the potential for improved data on reproductive rates for population management of baleen whales generally. Publisher PDF

Published
2023

6. Assessing variation in faecal glucocorticoid concentrations in gray whales exposed to anthropogenic stressors

Author

Pirotta, Enrico, primary, Fernandez Ajó, Alejandro, additional, Bierlich, KC, additional, Bird, Clara N, additional, Buck, C Loren, additional, Haver, Samara M, additional, Haxel, Joseph H, additional, Hildebrand, Lisa, additional, Hunt, Kathleen E, additional, Lemos, Leila S, additional, New, Leslie, additional, and Torres, Leigh G, additional

Published
2023
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7. La Patagonia Sumergida: descubriendo las profundidades de los lagos del Sur

Author

Lallement, Mailén Elizabeth and Fernandez Ajó, Alejandro

Subjects
purl.org/becyt/ford/1 [https], purl.org/becyt/ford/1.5 [https], PATRIMONIO SUBACUÁTICO, Oceanografía, Hidrología, Recursos Hídricos, LAGOS, CONSERVACIÓN, CIENCIAS NATURALES Y EXACTAS, Ciencias de la Tierra y relacionadas con el Medio Ambiente
Abstract

La Patagonia Argentina conjuga en su extenso territorio diversos elementos naturales: montañas, mesetas, costas, desiertos, bosques, lagos y ríos. Dominada por pastos y arbustos bajos hacia el este, se transforma hacia el oeste en un bosque denso hasta llegar a la cordillera de los Andes. La belleza colosal de sus paisajes ha sido ampliamente reconocida y sus imágenes recorren todo el mundo despertando admiración. Sin embargo, es poco lo que se conoce de su patrimonio subacuático y la importancia que éste presenta en términos de procesos ecológicos. En este artículo, te invitamos a sumergirte en los lagos de la Patagonia Argentina para conocer parte de su historia, sus componentes y los procesos ecológicos que se encuentran bajo la superficie de los lagos. Fil: Lallement, Mailén Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentina Fil: Fernandez Ajó, Alejandro. Arizona State University; Estados Unidos

Published
2019

8. El Mes de la Entomología: acercando el laboratorio de investigación científica a las escuelas de nivel inicial de la Patagonia

Author

Fischbein, Deborah, Pereira, Ana Julia, Fernandez Ajó, Alejandro Apolo, and Corley, Juan Carlos

Subjects
Ciencias Biológicas, purl.org/becyt/ford/1 [https], COMPETENCIA CIENTÍFICA, Otras Ciencias Biológicas, ENSEÑANZA DE LAS CIENCIAS, purl.org/becyt/ford/1.6 [https], CIENCIAS NATURALES Y EXACTAS, INSECTOS, NIVEL PRIMARIO
Abstract

Fil: Fischbein, Deborah. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Fil: Fischbein, Deborah. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche. Laboratorio de Ecología de Insectos; Argentina Fil: Pereira, Ana J. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Fil: Pereira, Ana J. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche. Laboratorio de Ecología de Insectos; Argentina Fil: Fernandez Ajó, Alejandro A. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina Fil: Fernandez Ajó, Alejandro A. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche. Laboratorio de Ecología de Insectos; Argentina Fil: Corley, Juan C. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina Fil: Corley, Juan C. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche. Laboratorio de Ecología de Insectos; Argentina As science researchers we believe that teaching Natural Sciences at elementary school level is both a challenge for teachers and an excellent opportunity to establish the foundations of scientific thinking. “The Entomology Month” was a project, carried out by researchers and scholars from CONICET and INTA Bariloche, whose main objective was to improve the existing knowledge about insect biology. Activities were addressed to teachers and elementary school students from Bariloche and rural areas in NW Patagonia. The positive aspects of insects were especially highlighted, by enhancing their biological and applied importance, as well as their diversity and abundance. Twelve out of the 55 invited schools (both private and public) and 600 students were counted among the participants. The “Entomology Month” served both to address local scientist difficulties and to bring closer the figure of the scientist to teachers and students. Como investigadores en ciencias, entendemos que enseñar las ciencias naturales en la escuela primaria es un desafío para los docentes y una excelente oportunidad para sentar las bases del pensamiento científico. “El Mes de la Entomología” fue un proyecto llevado a cabo por investigadores y becarios del CONICET y del INTA Bariloche, cuyo objetivo principal fue mejorar el conocimiento existente sobre la biología de los insectos, de docentes y estudiantes de nivel primario de escuelas de Bariloche y escuelas rurales del NO de la Patagonia. Se resaltaron los aspectos positivos de los insectos, destacando tanto su importancia biológica y aplicada así como su diversidad y abundancia. Participaron un total de 12 escuelas de las 55 invitadas (entre privadas y públicas) y 600 estudiantes. “El Mes de la Entomología” fue una actividad que además sirvió tanto para explorar problemáticas científicas locales, como para acercar la figura del científico a los docentes y estudiantes.

Published
2015

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