ORIGINAL RESEARCH article
Front. Vet. Sci.
Sec. Veterinary Clinical, Anatomical, and Comparative Pathology
This article is part of the Research TopicEcophysiology: a Tool to Aid Wildlife Conservation and WellbeingView all 8 articles
Hematological and biochemical reference intervals for populations of seabird species from an Archipelago in Rio de Janeiro, Brazil
Provisionally accepted
Joana Maçaira1,2
Marthiellen Roosevelt de Lima Felix3,4Amanda de Oliveira Alcântara3,4
Paula Maçaira5,6
Larissa Schmauder Teixeira Da Cunha7
Marina Galvão Bueno2,8*Aline Moreira de Souza3,4*- 1Oswaldo Cruz Foundation (Fiocruz), Rio de Janeiro, Brazil
- 2Laboratory of Comparative and Environmental Virology, Rio de Janeiro, Brazil
- 3Universidade Federal Fluminense, Niterói, Brazil
- 4Veterinary School, Niterói, Brazil
- 5Pontificia Universidade Catolica do Rio de Janeiro, Rio de Janeiro, Brazil
- 6Department of Industrial Engeneering, Rio de Janeiro, Brazil
- 7Instituto Mar Adentro, Rio de Janeiro, Brazil
- 8Fundacao Oswaldo Cruz, Rio de Janeiro, Brazil
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Introduction: Establishing reliable hematological and biochemical reference intervals for seabirds is essential for health assessment, rehabilitation, and conservation programs. However, baseline physiological data for these animals remain scarce. This study aimed to determine hematological and biochemical reference intervals for two free-ranging seabird's species commonly found along the coast of Rio de Janeiro, Brazil: the brown booby, Sula leucogaster (Boddaert, 1783), and the magnificent frigatebird, Fregata magnificens (Linnaeus, 1758). Methods: Between March 2024 and May 2025, blood samples were collected from apparently healthy individuals in the Natural Monument of the Cagarras Islands Archipelago (MoNa Cagarras), the main breeding areas for these species in the State of Rio de Janeiro. Hematological and biochemical parameters were analyzed using standard laboratory procedures. Reference intervals were established following the guidelines of the American Society for Veterinary Clinical Pathology. Results: Overall, hematologic parameters for both species were similar to those previously reported for individuals maintained in rehabilitation centers. The most notable differences were observed in total thrombocytes and white blood cell counts, which presented higher values. Regarding biochemical parameters, uric acid and creatine kinase levels were higher in brown boobies. Conversely, alanine aminotransferase, aspartate aminotransferase and albumin levels were lower when compared to other reports. In frigatebirds, alanine aminotransferase levels were also elevated, but other parameters showed little variation. Discussion: For both brown boobies and magnificent frigatebirds, this study presented higher values in total thrombocytes and white blood cell counts, as well as uric acid and creatine kinase levels. These findings possibly reflect capture-related physiological responses from wild individuals. The reference intervals described here represent the first in situ values established for these two seabird species from the MoNa Cagarras in Brazil, providing essential baseline data for health and clinical evaluation, rehabilitation monitoring, and the conservation of tropical seabirds, while highlighting the importance of assessing the health of wild animals within their natural habitat.
Keywords: Biochemistry, Free-ranging, Fregata magnificens, Hematology, Sula leucogaster, Veterinary clinical pathology, wildlife
Received: 19 Nov 2025; Accepted: 02 Feb 2026.
Copyright: © 2026 Maçaira, Roosevelt de Lima Felix, de Oliveira Alcântara, Maçaira, Cunha, Galvão Bueno and Moreira de Souza. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence:
Marina Galvão Bueno
Aline Moreira de Souza
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