Geology topics

Kathleen M. Dudzinski

Publications and source records attributed to Kathleen M. Dudzinski.

3 recordsLinked to original sources

USGS2022

Atlantic spotted and bottlenose dolphin sympatric distribution in nearshore waters off Bimini, The Bahamas, 2003–2018

Within nearshore waters off Bimini, The Bahamas, Atlantic spotted ( Stenella frontalis ) and common bottlenose ( Tursiops truncatus ) dolphins are sympatric but separated spatially in different geographic areas and water depth ranges. Afternoon surveys during summer months across a 16-year period showed S. frontalis used the northern part of the nearshore area more, while T. truncatus used the southern area more. Generally, examination of geographic zones and water depth distributions of both species before and after construction of a pier in the study area suggested these dolphins were not impacted, long-term, by this anthropogenic activity. Still some differences in use of the nearshore area were identified. For water depth, S. frontalis varied use between 5–<12 m and 12–<20 m, depending on location along the coast. In contrast, T. truncatus consistently used the 5–<12 m depths. This difference may be related to how each species used the nearshore area, with T. truncatus feeding more and S. frontalis travelling and doing other activities. A small change in the distribution of S. frontalis by water depth off the northern coast of Bimini was found, specifically an increased use of deeper (12–20 m) water post 2014, which is unlikely an effect of pier construction as S. frontalis continued to use the 5–12 m depths as they had before pier construction. How this change might be related to an unprecedented 2013 S. frontalis immigration event, which might have disrupted the social structure, habitat/resource use, and distribution of both species, is discussed.

Bimini↗

USGS2021

Evidence for maternal style among adult female dolphins when sharing pectoral fin contacts with their calves

Adult bottlenose dolphins share pectoral fin contacts (PFC) to manage their social relationships but less is known about how mothers share PFC with their calves. Using a dataset collected over 16 years, we analyzed how 10 matrilines, including three second generation female dolphins in a maternal role, used PFC with their pre-weaned calves. Mothers had different rates of initiation with their calves forming a continuum from those initiating few contacts (15%) to those initiating more (44%). For mothers with all-aged calves, the lateral side was contacted the most to start interactions with mothers contacting body parts at a similar rate. All mothers assumed the same posture regardless of their role as initiator or receiver, with horizontal the most prevalent posture. Two maternal styles were found for PFC: high and low use of PFC. Within the high PFC group, there was individual variation that was related to calf sex. Even though evidence of maternal style was confirmed in PFC exchanges between adult female dolphins and their calves, the number of PFC shared between these kin was only ~9% of all documented PFC contacts (N = 4,345) over 16 years, suggesting that other forms of tactile contact may be more important within the confines of the mother-offspring relationship in delphinids.

Bailey’s Key, Roatan↗

USGS2020

A new approach to the study of relationship quality in dolphins: framework and preliminary results

Proximity and synchronous behaviours from surface observations have been used to measure association patterns within and between dolphin dyads. To facilitate an investigation of relationship quality in dolphins, we applied a method used for chimpanzees and ravens that examined three main components to describe relationships: value, security, and compatibility. Using pilot data from a long-term study of two study populations for this preliminary assessment, these three components were extracted from PCA analysis of eight behavioural variables with more than 80% variance accounted for in both study groups. Only pair swim position differed between groups. Although value, security, and compatibility are abstract terms, each is based on behaviours identified as important in dolphin social life, at least for these two populations. Examining relationship quality in dolphins with a method used to illustrate dyadic differences for chimpanzees and ravens allows for a quantitative, comparative assessment of sociality across disparate taxa. Although these three species are diverse in their anatomies and in their social habitats (e.g., aquatic, terrestrial, aerial), they may well share the basic societal building blocks in the factors affecting how relationships are formed. We discuss how an examination of these behavioural variables facilitates understanding relationship quality in dolphins, as well as how dolphin relationships fit into the context of social animals’ society.

Bimini Islands, Great Bahama Bank, Roatan Island↗