Latin American Journal of Aquatic Mammals

Lesions on the jaws of an adult male orca (Orcinus orca) from Punta Norte, Argentina

2026-05-19T15:41:34+00:00

The Punta Norte Patagonia orca (Orcinus orca) population/ ecotype exhibits a unique foraging strategy that involves intentionally stranding onto beaches to capture pinnipeds, primarily Southern sea lions (Otaria byronia, formerly Otaria flavescens). One adult male orca from this population was a prolific hunter. Between 1 February and 30 April, each year from 2006 to 2011, he conducted a total of 319 attacks and 173 successful captures. The highest number of attacks (n = 122) and captures (n = 76) in a single season both occurred in 2008. During that same period, he intermittently presented with multiple bilateral lesions on his maxillae and mandibles. We present milestone images (n = 6) and paired same-day images (n = 16; 8 pairs) documenting the progression of these lesions. Using standardised descriptive criteria, we compared lesion characteristics across time, between left and right sides, and between the maxillae and mandibles. We developed the Lesion- Eye-patch Ratio (LER) to quantify lesion area relative to the corresponding eye patch area using ImageJ software. The highest paired image LER was 2.02 (recorded in 2009), indicating lesions more than twice the size of the eye patch, whilst the lowest was 0.16 (recorded in 2007). This unique dataset provides evidence of what we believe to be the longest documented duration of persistent lesions in a free-ranging orca. We speculate that the most likely contributing factor was temporary mandibular misalignment associated with beach egress during intentional stranding events. Such misalignment may have caused teeth to puncture soft tissues of the mouth, leading to infection and the development of externally visible lesions. A possible genetic predisposition cannot be excluded, as there is evidence (albeit limited) that this adult male’s presumed older brother exhibited smaller but similar lesions. The survival and continued hunting success of this individual demonstrates that orca with significant lesions can forage effectively. These observations support a reassessment of the management framework concerning the rescue and release of injured orca whose lesions might otherwise be considered debilitating, as this male not only hunted for himself, but he also captured prey and provisioned other orca in the population.

Acoustic and behavioral responses of the American manatee (Trichechus manatus) to anthropogenic disturbances: an integrative systematic and bibliometric review.

2026-06-05T13:39:57+00:00

The American manatee (Trichechus manatus) faces increasing anthropogenic threats in its habitat. In this integrative review, we synthesize current knowledge on the behavioral and acoustic responses of manatees to anthropogenic disturbances, including tourism activities, environmental noise, and port operations. Our literature search identified 40 studies published between 2000 and 2025 that investigated the responses of Florida (T. manatus latirostris) and Greater Caribbean (T. manatus manatus) manatees to anthropogenic impacts. Results show that manatees adjust their behavior in response to disturbances, including changes in movement, activity patterns, and habitat use. Acoustic responses include alterations in vocalization duration and rate. Most studies were conducted in Florida, USA, on Florida manatees, whereas the Greater Caribbean manatee was more extensively studied in Brazil, Mexico, and Belize. We identified important gaps, such as the lack of studies on the impact of recreational aquatic tourism and direct human interactions, especially in Central and South America. Addressing these gaps is crucial to improve conservation and management strategies for the American manatee.

Molecular identification of a fin whale stranded in Veracruz, southern Gulf of Mexico

2026-07-29T21:00:26+00:00

Baleen whale strandings are rare in the southern Gulf of Mexico and can provide valuable molecular information where species are infrequently documented. We analyzed tissue from a highly decomposed whale stranded on the central coast of Veracruz, Mexico, by amplifying and bidirectionally sequencing the mitochondrial DNA control region. A total of four chromatogram reads were generated: one forward and one reverse read for each of the two overlapping amplicons (5′ and 3′). Accordingly, nucleotide positions located within the overlap between fragments were independently covered by up to four reads, whereas positions outside the overlap were supported by the corresponding forward and reverse reads. A nucleotide BLAST search identified the specimen as a fin whale (Balaenoptera physalus), showing 99% identity to the mitochondrial reference sequence MF409243.1. Three nucleotide substitutions relative to that reference occurred at positions 15499 (A>G), 15650 (T>C), and 15754 (C>T). The three nucleotide substitutions were each supported by high-quality base calls and by all independent reads covering the corresponding position. In a maximum-likelihood analysis, the Veracruz sequence clustered within a clade containing sampled North Atlantic fin whale control-region sequences. The specimen’s estimated length (~11 m) was consistent with a young individual, although decomposition prevented definitive age classification. The mitochondrial result indicates affinity with sampled North Atlantic diversity but does not establish geographic origin or stock identity. These results provide molecular confirmation of a rare fin whale occurrence in the southern Gulf of Mexico and demonstrate that highly decomposed stranding material can retain sufficient good quality mitochondrial DNA for reliable species identification. Systematic tissue preservation and archiving during stranding responses can therefore improve verified occurrence records in poorly documented regions. This case underscores the scientific value of collecting and preserving stranded specimen samples from vulnerable species that are exposed to heavy maritime traffic, artisanal fisheries, and ongoing oceanographic variability in poorly documented regions of the Gulf of Mexico.

Inferring gestational diet in free-ranging Greater Caribbean manatee (Trichechus manatus manatus) using newborn hair isotopic signatures

2026-08-19T03:12:33+00:00

Species feeding habits can be accessed in a variety of ways, such as fecal samples and stomach contents. However, these methods reflect only the individual’s recent diet, disregarding a broader perspective of feeding habits along a temporal scale. Such differences can be evaluated by analyzing inert biological samples, like hair and skin tissues, which absorb and preserve isotopic signatures over time. In this study we analyzed hair samples from nine stranded manatee calves, in order to trace their mothers’ diet during gestation, an innovative attempt for this species which is currently classified as Critically Endangered of extinction in Brazil. Our sample, however small, contained data distributed along four Brazilian states, covering half of the current occurrence area of the species in the Brazilian coast. δ¹³C values showed variability among calves, particularly in individuals aged 0.9 - 1.5 months. In contrast δ¹⁵N values, carbon and nitrogen concentrations presented very similar values, regardless of calf age. δ¹³C values had a strong positive correlation with size at stranding even when controlled by age, suggesting that enriched δ¹³C signatures correspond to the production of larger calves. Despite our small sample size, here we present a substantial contribution to the knowledge of the diet of free-ranging females, use of habitat during pregnancy and how it varies according to resource availability. Furthermore, our findings support the hypothesis that nutritional intake during gestation periods might have a long-term impact on calf growth and development.

Serial endoscopic characterization of foreign body-associated esophageal and forestomach ulcer resolution in Tursiops truncatus

2026-08-30T14:44:59+00:00

Stranding of a juvenile pygmy sperm whale (Kogia breviceps) in Utila Island, Honduras, with evidence of plastic ingestion in the Western Caribbean

2026-09-10T01:47:37+00:00

Editorial: Seasons of change

2026-10-30T16:21:48+00:00