Eric Angel Ramos

University of Vermont | UVM · Department of Biology

Assessing the body condition of wild animals is necessary to monitor the health of the population and is critical to defining a framework for conservation actions. Body condition indices (BCIs) are a non-invasive and relatively simple means to assess the health of individual animals, useful for addressing a wide variety of ecological, behavioral, a...

Assessments of individual animal health alerts to early signs of population level effects in wildlife but often rely on logistically complex wild animal captures, hindering our understanding of the wellbeing of populations in regions with limited resources. Here, we tested photogrammetry methods using small aerial drones for accurate morphometric m...

Vocal activity and signal characteristics of mammals are driven by several factors that result in both stability and plasticity over multiple time scales. All three extant species of manatee communicate with several calls that are especially important for maintaining contact between cows and calves. Determining if calf calls differ across manatee s...

The dorsal fin plays important kinematic and hydrodynamic roles in dolphins and are related to physiological and environmental adaptation processes. Differences in dorsal fin shape have been recently associated with geographic variation, habitat specialization between ecotypes, and ontogenetic factors. We studied dorsal fin variation across several...

The African manatee (Trichechus senegalensis) is an elusive, data-deficient, and endangered species which inhabits marine and freshwater systems throughout Western and Central Africa. A major challenge in understanding the species ecology and distribution is the difficulty in detecting it using traditional visual surveys. The recent invasion of Gia...

Understanding predator-prey relationships is critical in ecology, but relatively challenging when investigating elusive marine megafauna. In this study, we document the presence of shark-inflicted injuries on coastal bottlenose dolphins (Tursiops truncatus) in the Mesoamerican Reef System using photo-identification methods. We analyzed data from a...

The Antillean Manatee (Trichechus manatus manatus), an herbivore mammal which inhabits coastal and wetlands areas from Mex- ico and Central America to northern Brazil, is considered a threatened species by the International Union for Conservation of Nature (IUCN). Herein, the usage YOLOv5, a Deep Learning based model, was suc- cessfully implemented...

Sleep is a fundamental biological process in animals. Identifying correlates between vertebrate and invertebrate sleep facilitates the development of robust definitions for behavioral sleep needed to understand how sleep evolved in distantly related organisms. Cephalopods are cognitively complex animals that display alternating patterns of sleep st...

SummaryInfanticidal behavior (i.e., the intentional killing of young) is common in the animal kingdom. Common bottlenose dolphins (Tursiops truncatus) engage extensively in intraspecific agonistic behaviors, and infanticidal behavior has been documented in many dolphin populations. However, these behaviors remain poorly understood in dolphins as de...

Lay abstract: Bottlenose dolphins display diverse feeding behaviors. Here, we report mud ring feeding behaviors by bottlenose dolphins in an estuary shared between Belize and Mexico. We detected four mud ring feeding events in boat- and aerial-based observations. In visual searches of Very High Resolution (VHR) satellite imagery, we detected mud ri...

Vocal production learning is the ability to modify a vocal output in response to auditory experience. It is essential for human speech production and language acquisition. Vocal learning evolved independently several times in vertebrates, indicating evolutionary pressure in favor of this trait. This enables cross-species comparative analysis to be...

Documenting marine mammal strandings provides important information needed to understand the occurrence and distribution patterns of species. Here, we report on strandings of cetaceans on the Pacific ( n = 11) and Caribbean ( n = 2) coasts of Nicaragua, documented opportunistically from 2014 to 2021. Strandings included three species of baleen whal...

Marine mammals inhabit aquatic worlds where their subsurface behavior, cryptic surface profiles, and movements make them difficult to study. New tools are needed to study coastal marine mammals in a world increasing impacted by climate change related shifts in weather and animal distribution patterns. Unmanned aerial systems (UAS) are important rem...

Even among the understudied sirenians, African manatees (Trichechus senegalensis) are a poorly understood, elusive, and vulnerable species that is difficult to detect. We used passive acoustic monitoring in the first effort to acoustically detect African manatees and provide the first characterization of their vocalizations. Within two 3-day period...

West Indian manatees (Trichechus manatus) are separated into two allopatric subspecies: the Florida manatee (T. m. latirostris) and the Antillean manatee (T. m. manatus). In the winter of 2020-2021, an adult manatee was sighted off the coast of Cancun, Quintana Roo, Mexico, in areas where Antillean manatees are not typically seen. The individual ha...

Context. Unmanned aerial vehicles or drones are powerful tools for wildlife research. Identifying the impacts of these systems on target species during operations is essential to reduce risks of disturbance to wildlife, to minimise bias in behavioural data, and to establish better practices for their use. Aims. We evaluated the responses of captiv...

We provide new information of the spatial and temporal distribution, as well as natural history of the killer whale in the Caribbean Sea, on the basis of 332 records.

Food sharing is common in the animal kingdom, but rarely reported in marine mammals since it is challenging to observe their feeding behaviors in the wild. Here, we describe food sharing by rough-toothed dolphins, an open ocean dolphin species, off the southwestern coast of Mexico. We observed two dolphins exchanging a fish back and forth during a...

Baseline data on the distribution and occurrence of marine mammals are needed to better understand their role in marine ecosystems and to protect them from the negative impacts of climate change and human activity. Here, we report the results of vessel-based surveys to document marine mammals throughout the territorial waters of Belize in the Weste...

In this Short Communication, we document the stranding of a pregnant dwarf sperm whale on the southeastern coast of the island of Utila in Honduras.

Bottlenose dolphins (Tursiops truncatus) of the Bocas del Toro archipelago are targeted by the largest boat-based cetacean watching operation in Panama. Tourism is concentrated in Dolphin Bay, home to a population of resident dolphins. Previous studies have shown that tour boats elicit short-term changes in dolphin behavior and communication; howev...

We report the northernmost records to date of Southern Hemisphere humpback whales migrating from the Antarctica Peninsula to the Pacific coast of Nicaragua during the austral winter. From 2015 to 2018, data from opportunistic sightings of humpback whales were gathered during boat trips in Nicaragua, crowd-sourced through local citizen science effor...

Population assessments and species monitoring for many endangered marine megafauna are limited by the challenges of identifying and tracking individuals that live underwater in remote and sometimes inaccessible areas. Manatees can acquire scarrings from watercraft injury and other incidences that can be used to identify individuals. Here we describ...

Antillean manatees produce vocalizations reported to be important for communication, but their vocal behavior throughout their geographic range is poorly understood. A SoundTrap recorder (sample rates: 288/576 kHz) was deployed in Belize to record vocalizations of wild manatees in a seagrass channel and of a young rehabilitated and released manatee...

Body condition index (BCI) is an important morphometric measure for monitoring the health status of sirenians. The capture and handling of wild manatees enables accurate body measurements but are invasive, expensive and logistically challenging. We tested the use of small drones to remotely collect morphometric data from captive Antillean manatees...

Manatees can acquire permanent scarrings from watercraft injury and other incidences that can be used to photo-identify individuals over time and space. Small drones are affordable and practical platforms to study and monitor wildlife. We propose a novel method for photo-ID of Antillean manatees (Trichechus manatus manatus) using aerial imagery cap...

The discovery of Nicaragua as a feeding stopover for migrating humpback whales could indicate it represents a previously undocumented feeding site or that whales are seeking new feeding sites.

The vocal repertoire of the antillean manatees in Mexico and their association with different behaviors is largely unknown. We try to identify and classify the vocal repertoire of a captive population of manatees in Quintana Roo, Mexico. It was evidenced that the presence of environmental noise, sounds of other animals in captivity, anthropogenic s...

In-depth marine mammal survey work has never been conducted before in Guerrero, SW Pacific Mexico and no official protection or monitoring measures are in place. We conjectured that humpback whales found off of Mainland Mexico include two distinct population segments, classified as threatened and endangered. In order to contribute to a clearer char...

Marine mammal watching is becoming an important non-consumptive use of wild megafauna in Mexico, mainly in the Pacific and Gulf of Mexico. Here, we present the first report of watching tourism targeting dolphins (Tursiops truncatus) and manatees (Trichechus manatus manatus) in the Mexican Caribbean (SKRB). We applied 64 semi-structured interviews t...

Marine mammals sometimes develop complex feeding behaviors driven by prey availability in their habitats and the capacity for social learning. Bottlenose dolphins display diverse foraging tactics, oftentimes involving complex series of learned behaviors. Rarely have the same strategies been detected in geographically distinct populations. Mud ring...

(Publication in progress)

The Sian Ka’an Complex (SKC) is a relevant refuge for Caribbean manatees (Trichechus manatus manatus) in Quintana Roo, Mexico, due to the availability of high quality habitats for manatee feeding and calving. However, the recent increase of tourism affluence has raised concerns on the fate of this manatee population. We started a long-term monitori...

Dolphins of the genus Stenella occur in pelagic waters of both tropical and warm-temperate oceans. Three species, the Atlantic spotted dolphin (Stenella frontalis), the pantropical spotted dolphin (S. attenuata), and the spinner dolphin (S. longirostris) are abundant worldwide, but in the Caribbean Basin they have been poorly studied and informatio...

Presented in contribution to the State of Science workshop hosted by the New York State Energy Research and Development Authority and Biodiversity Research Institute. Relevant discussions relating to offshore windfarm development proposed by the Bureau of Ocean Energy Management.

Manatees Trichechus manatus manatus occupying the Caribbean coast of Mexico (Mx) and the entire coast of Belize (Bz) belong to the same sub-population, and mortality analysis must be conducted on a regional scale. Here, we updated the review of manatee mortality cases reported between 2008 and 2018 along the Caribbean coast of Mexico and in Belize...

Unmanned aerial systems (UAS) are powerful tools for research and monitoring of wildlife. However, the effects of these systems on most marine mammals are largely unknown, preventing the establishment of guidelines that will minimize animal disturbance. In this study, we evaluated the behavioral responses of coastal bottlenose dolphins (Tursiops tr...

Thesis protocol

Lobomycosis and lobomycosis-like diseases (LLD) (also: paracoccidioidomycosis) are chronic cutaneous infections that affect Delphinidae in tropical and subtropical regions worldwide. In the Americas, these diseases have been relatively well-described, but gaps still exist in our understanding of their distribution across the continent. Here we repo...

Drones are important tools for a wide array of applications in scientific research and monitoring with marine mammals. Few studies have examined if different crafts and systems affect the behavior of animals, or attempted to identify factors influencing the probability of these responses or their subsequent effects. Some published studies on effect...

El manatí antillano (Trichechus manatus manatus) se encuentra en peligro de extinción y es protegido por la legislación internacional y mexicana. La especie es el mamífero marino más común del Caribe mexicano, en donde se estima una población de aproximadamente 250 individuos. Sin embargo, los censos de la población son esporádicos, debido al alto...

Characterizing species occurrence, abundance, and distribution is critical to the management of natu- ral resources and the conservation of biodiversity. In the Western Caribbean, little information exists on the occurrence of aquatic mammals along the Mesoamerican Barrier Reef System and adja- cent aquatic ecosystems. Herein, we present the first...