Karin L. Hartman

Nova Atlantis Foundation

One of Risso's dolphin's distinctive characteristics is the tendency to "lighten" with age due to the accumulation of unpigmented scars. These accumulated scars may provide an indication of age. Photographic skin recaptures gathered from 61 freeranging animals over a period of 15 years were analyzed to develop a skin classification model in 6 skin...

Knowledge of the residency patterns of marine mammals is an important element for management and conservation strategies. Here we investigate a population of Grampus griseus off Pico Island, Azores. Our data set covers the period 2004–2007, based on at-sea observations of 1,250 individually identified animals, 303 of known or assumed sex. Using pho...

In this study, we present for the first time a model for the social structure of Risso's dolphins (Grampus griseus Cuvier, 1812). Over the period 2004-2006, 1028 Risso's dolphins were identified at Pico island, Azores. Individuals sighted on 10 or more occasions were included in the analysis of social structure (n = 183). High resighting rates indi...

Calving can be a critical period for cetaceans. Areas providing security for vulnerable calves, and high food availability for lactating females can be critical habitats requiring specific conservation measures. Here, we test the hypothesis that calving and nursing habitat could be defined for Risso’s dolphins (Grampus griseus). We investigated the...

Behavioral responses of Risso's dolphins (Grampus griseus) to whale watching vessels were studied off Pico Island, Azores. Dolphin behavior was studied from a land-based lookout, enabling observations of groups in the absence and presence of vessels. The number of whale watching vessels showed a clear seasonal pattern, dividing the whale watching p...

Risso’s dolphins ( Grampus griseus ) in the Azores maintain a sexually stratified community with males forming stable clusters, whereas females tend to associate in temporally stable units when calving and nursing. Large relative testes size indicates a mating system based on sperm competition. Small sexual size dimorphism and long interbirth inter...

Mating and sociosexual behaviors of cetaceans are challenging to study in nature because most species spend only brief periods of time at the surface and most copulation and courtship occurs underwater. Recent advancements in technology have enabled a new perspective on these behaviors. Drones, or unoccupied aerial systems, have revolutionized stud...

Monitoring trends in occurrence of different age-classes in wild populations is important for conservation and management decisions. Waters off Pico Island host a resident population of Risso’s dolphins (Grampus griseus), whose social structure is defined as a “stratified community”. Within this population, three different group types, defined by a...

As apex marine predators, cetaceans have many important ecological roles in marine environments, and are often recognised as ecosystem sentinels. In many areas cetacean populations are vulnerable and being affected by several threats, including climate change, pollution, and human activities. With this study we aim to explore the spatio-temporal tr...

Wide-ranging connectivity patterns of common bottlenose dolphins (Tursiops trunca-tus) are generally poorly known worldwide and more so within the oceanic archipelagos of Macaronesia in the North East (NE) Atlantic. This study aimed to identify long-range movements between the archipelagos of Macaronesia that lie between 500 and 1,500 km apart, and...

Relationships between social status and relative position of group-living animals have been described in a variety of species. For wild cetaceans, who spend most of their time underwater, collecting detailed, continuous data to assess such relationships depends highly on group size, formation, shyness of animals and observation platform. We test a...

Photo-identification is a widely used non-invasive technique in biological studies for understanding if a specimen has been seen multiple times only relying on specific unique visual characteristics. This information is essential to infer knowledge about the spatial distribution, site fidelity, abundance or habitat use of a species. Today there is...

Photo-identification is one of the best practices to estimate the abundance of cetaceans and, as such, it can help to obtain the biological information necessary to decision-making and actions to preserve the marine environment and its biodiversity. The Risso’s dolphin is one of the least-known cetacean species on a global scale, and the distinctiv...

Off Pico island (Azores), a long-term study has been focusing on monitoring cetacean species presence in the Bay of Ribeiras. Data were collected through standardized land surveys from a fixed look-out point at 45m altitude. Surveys (average 20 min. per survey) were conducted on a daily basis with 2-hour intervals to avoid double counting. Next to...

Sightings of false killer whales were recorded during whale watching tours from 1993-present. ID photos were taken with various SLR cameras and lenses. Dorsal fins were cropped and matched manually. For this study, only marked individuals were matched. The letter "A" was attributed to distinctively marked individuals, while "B" was attributed to le...

The Risso’s dolphin (Grampus griseus) is a frequently sighted species in the Azores. Major studies concerning this species have been conducted in the central group of the archipelago, where social structure, residency and nursery patterns have been investigated for a long term followed population off Pico Island (n=1250). Here, we aim to identify a...

Aim The knowledge of a species biogeographical patterns greatly enhances our understanding of geographical ecology, which can improve identifying key conservation needs. Yet, this knowledge is still scarce for many marine top predators. Here, we aim to analyse movement patterns and spatial structuring of a large predator, the short‐finned pilot wha...

Movement patterns of delphinid populations are generally known to occur within specific geographical areas; with the exception of the killer whale (Orcinus orca). Additionally, knowledge of wide-ranging migrations in these animals are mainly attributed to individual records with limited information on their social structure, residency status or pur...

Aim The heterogeneity of the marine environment is thought to be the origin of marine biodiversity, often delineated in marine biogeographical provinces. Cetaceans are highly mobile aquatic mammals, but even those species inhabiting seemingly boundary‐free open waters are found to exhibit degrees of population structure, often attributed to ecologi...

Humpback whales use the Azores as a stopover feeding point on their migration

Each year, a phytoplankton spring bloom starts just north of the North Atlantic Subtropical Gyre, and then expands northwards across the entire North Atlantic. Here, we investigate whether the timing of the spring migration of baleen whales is related to the timing of the phytoplankton spring bloom, using 4 yr of dedicated whale observations at the...

The Azorean archipelago is characterized by deep coastal waters, hence it is possible to observe deep diving cetaceans close to shore, such as sperm whales, northern bottlenose whales, Sowerby's and other beaked whales. The aim of the present study was to determine the temporal and spatial distribution of Hyperoodon ampullatus of Pico Island, Azore...

The Northern bottlenose whale (Hyperoodon ampullatus) is a deep-diving species that belongs to the family Ziphiidae. This species can reach up to 9.5 meters in length and is distributed in the North Atlantic ocean, preferring cold waters. Very little is known about this species, except for a well-studied population appearing at the Gully, an underw...

The archipelago of the Azores represents a special area of cetacean ocurrence, mostly due to its oceanic nature. In this area two small delphinids, the common dolphin and the Atlantic spotted dolphin, the former seeming to be present all year around, while the latter seems to be seasonal (summer). In this study we analyse their respective distribut...