Research

This section presents the research projects I am currently leading and contributing to. Detailed information about each project, including objectives, methods, and progress, is provided below. For collaboration opportunities or project-related questions, please contact me via the contact page.

3501: Investigation of underwater and surface social behavior of Black Sea harbour porpoises (Phocoena phocoena relicta) using unnamed technologies

Status: In progress

Position: Project leader

The Black Sea harbour porpoise (Phocoena phocoena relicta) is an endemic and poorly studied subspecies of small cetaceans. Systematic data on their social organization, mother–calf interactions, and sexual (reproductive) behavior are almost entirely lacking. Existing information is fragmentary and primarily based on observations of other populations or individuals held in captivity. This project aims to investigate the social and reproductive behavior of the Black Sea harbour porpoise using an integrated approach, including aerial observations with drones, underwater video recordings, and vessel-based visual surveys. The main objectives are to identify the characteristics of social organization, assess the role of physical contact, spatial arrangement, and visual communication in maintaining social bonds and mother–calf interactions, and study reproductive behavior. The project also aims to estimate the detection probability parameter g(0) to improve population size assessments. Fieldwork will be conducted in the coastal waters of Zonguldak Province, Türkiye, along the shoreline from Ereğli to Filyos, covering approximately 80 km. The area features diverse seafloor morphology, including rocky shores, deep bays, and sandy beaches. This variability, along with seasonal upwellings, provides favorable conditions for observing harbour porpoise and examining mother–calf pairs and mating behavior. The project is planned over a 31-month period: during the two field seasons, systematic surveys will be conducted using drones and underwater video, data on group composition and size will be collected, social interactions will be documented, and anthropogenic pressures recorded; parallely, the collected data will be analysed, g(0) will be determined, a digital database of photos and videos will be created, and publications and conservation recommendations prepared. The expected outcomes of the project include the first systematic study of social and reproductive behavior of the Black Sea harbour porpoise in the region, creation of a long-term monitoring database, development of species conservation recommendations, and increased ecological awareness among the local community and scientific audience.

1001: Comprehensive monitoring of bottlenose dolphins (Tursiops truncatus) and common dolphins (Delphinus delphis) in the Black Sea and the Istanbul Strait using photo-identification "CetaFin Project"

Status: In progress

Position: Scholarship holder

The most observed species of the Delphinidae family in Turkish waters are bottlenose dolphin (Tursiops truncatus) and common dolphin (Delphinus delphis). Both of these species are distributed across all of Turkish waters. Their populations are threatened by anthropogenic factors, including bycatch, decline in prey availability due to overfishing, pollution and disease related mass mortalities. Although both migratory and resident populations have been identified for these species, studies conducted in Turkish waters are limited and insufficient to fully understand their population dynamics. To gain knowledge about site fidelity and population dynamics of these species help us understand their usage of habitat and how they are affected by anthropogenic factors. This project aims to study the long term site fidelity of bottlenose and common dolphins using photo identification. We will focus on three regions along the Turkish Black Sea coast and the Istanbul Strait. Each of these regions represents different levels of anthropogenic impacts. Visual assessment of the body injuries will be used as indicators of potential threats. To date, most of the cetacean studies conducted in the Black Sea are focused on understanding the current status. With the results of this study, the migratory movements of bottlenose and common dolphins in the southern Black Sea will be revealed for the first time. The project plans to conduct 45 boat-based surveys over a two year period in the Istanbul Strait, Sinop and Zonguldak regions using small vessels. The surveys will be conducted in suitable weather conditions (Beaufort <2, no rain and good visibility). Dorsal fin pictures will be taken using DSLR and SLR cameras equipped with telephoto lenses and when it is possible, aerial images will be taken using drones. Individual dolphins will be identified based on their unique dorsal fin markings and photographs of identified individuals will be cataloged according to standardized protocols. The data collected from Istanbul, Sinop and Zonguldak will be analyzed using QGIS and relevant packages within the R software. The results will help us understand the local abundance and distribution, site fidelity, temporal and spatial movements and exposure to human based activities' pressures. This versatile approach will offer a comprehensive understanding of the ecological dynamics of the dolphins in the region. If the data are suitable, they will also be evaluated for a preliminary study on the population health and welfare of bottlenose dolphins and mallards.

1001: Determination of trends in lateralisation, group number and vocal activities of mother-calf pairs of bottlenose dolphins

Status: In progress

Position: Project leader

This project aims to study mother-calf interactions in bottlenose dolphins (Tursiops truncatus) on the southwestern Black Sea coast, focussing on their social structure, vocal communication, occurrence and group dynamics. Understanding these interactions is crucial as such behaviours are essential for the survival and development of the calves in order to implement further effective conservation programmes to protect these species that are important to the marine ecosystem. The study will fill a significant knowledge gap, as there is a lack of comprehensive research on dolphin populations in the Black Sea. This project is characterised by the innovative integration of photo-identification, drone surveillance, underwater photography and acoustic analysis. Such a combined approach has not previously been applied to the study of bottlenose dolphins in the Black Sea, making this research ground-breaking in its scope. The analysis of social structures through lateralisation patterns and group composition with the aim of categorising these relationships by age class, as well as vocal activity, will provide new insights into the behaviour of mother-calf pairs. The study will be conducted in a 100 km long coastal area in the province of Zonguldak, covering approximately 730 km². The fieldwork will be carried out under favourable weather conditions, using small boats to approach the dolphin groups without disturbing them. Drones and underwater cameras will be used to collect behavioural data and confirm group composition, including the presence of calves. Photo-identification techniques will be used to catalogue dorsal fin markings and determine age classes. The photographic material obtained will also be used to categorise the spatial orientation of mother-calf pairs and to investigate factors that disturb bottlenose dolphins. Acoustic recordings will be made with sensitive hydrophones to document vocal communication. This extensive data collection will be followed by detailed statistical analysis using established protocols such as age identification keys, categorisation of calf position, whistle frequencies and their duration, time series of occurrence and group size measurements. The data will be statistically analysed with R software, using the packages required for specific analyses: R stat for time series analysis, MuMln for the study of factors influencing dolphin presence. Raven Pro software will be used to create and label spectrograms for all whistles produced by the animals. The project is led by a young but experienced scientist who graduated in 2023 and has seven years of experience in researching cetaceans in the Black Sea. The team also includes experts in theoretical biology and wildlife photography, whose skills in mathematical modelling and cetacean imaging will be crucial to the success of the project. The project is divided into seven work packages, each addressing key aspects of dolphin behaviour, its disturbance, vocalisation, group structure and dynamics of occurrence. The involvement of additional researchers, including a Masters student, will ensure that the project is managed efficiently and that its results will contribute to academic and educational goals. The project is expected to have a significant impact on the conservation and management of bottlenose dolphins in the Black Sea. Through the creation of photo-identification and acoustic survey catalogues, this study will provide a permanent resource for future research at local and international levels. The results will be crucial for developing habitat conservation strategies, promoting sustainable management of marine resources and improving fishing practises. The results will also be disseminated through international conferences and publications, contributing to the scientific community’s understanding of dolphin behaviour. In addition, the innovative use of technologies such as drones and underwater cameras can inspire further research and conservation efforts in Türkiye and beyond. Finally, the project will contribute to the training of new specialists in marine biology and thus support long-term conservation efforts.

A bottlenose dolphin female with its newborn

1001: Observations of cetacean and pinniped marine mammals in the West Antarctic Peninsula and Barents Sea regions: Photographic identification, encounter rate and abundance estimation studies

Status: 2022-2024

Position: Scholarship holder

Within the scope of TUBITAK Polar studies, the Department of Life Sciences, Polar Biodiversity sub-department has stated that “Making an inventory in terms of the use of living resources, in other words, completing biodiversity studies is considered as the first and indispensable step for this work”. Our project proposal aims at determination of marine mammal species and their relative abundances during the scientific expeditions in both polar areas, via the construction and analysis of comprehensive photographic catalogs. Cetacean marine mammals will be recorded by observation and documented by photography from the marine vessel desk. Pinniped marine mammals will be recorded by the observation and photography from the ship desk, as well as by drone footage. The species will be identified and the numbers of registered individuals will be recorded. Their relative abundance of species will be calculated on a regional basis according to the number of records. The photos of the individuals taken will be cataloged and the photos suitable for the photo identification studies will be selected. Possible matches will be determined by comparing the photos in the catalog with those in the existing available catalogs. Comparitions will be made both manually and by some existing software programmes. In addition, our catalog data will be added to the publicly available catalogs and will be kept open to the access of researchers working in this field, thus ensuring a long-term scientific outreach. The long-term accumulation of similar data will contribute to the studies of monitoring and interpreting the effects of global climate changes. In the project, a researcher and a doctoral fellow will be employed in addition to the coordinator, and a researcher will be trained in this field. Project results will be presented in the form of scientific articles and conference papers.

Fur seal (by M. Sözen)

Weddell seal (by M. Sözen)

Humpback whale (by M. Sözen)

1002: Assessment and monitoring of distribution and abundance of bottlenose and common dolphins (Delphinidae) along the coast of Zonguldak region, the southwestern Black Sea

Status: 2021-2022

Position: Project leader

To understand significance of effect of human activity and habitat modification on the surrounding environment is possible through gaining of knowledge about ecological aspects of species that inhabit a certain area. Based on the data gained during boat based surveys over a continuous period from November 2021 to October 2022, we present (1) the analysis of the site fidelity for the bottlenose dolphin, (2) the first photo-identification catalogue of individuals from Delphinidae, (3) encounter rates, the total abundance and density of individuals for all three Black Sea cetacean species: common dolphin (Delphinus delphis), bottlenose dolphin (Tursiops truncatus), and harbour porpoise (Phocoena phocoena), in the adjacent waters of Zonguldak, Türkiye. Additionally, we recorded and classified the prevailing floating litter in the region of the study derived from visual observations according to the boat based surveys. 55 individuals of the bottlenose dolphin and 32 individuals of the common dolphin considered as well marked and slightly marked were identified in 2021-2022. The study showed that the adjacent waters of Zonguldak are used by cetaceans of Delphinidae; low values of site fidelity metrics were obtained and the high number of transient individuals of the bottlenose dolphin was recorded. In this case, we speculate that the study area is only a part of the distributional range of these species. In May and August of 2022 we completed line transect surveys of the local populations of three species of the Black Sea cetaceans in the coastal waters between Ereğli and Filyos to quantify the cetacean abundance. Temporal fluctuations were found in the occurrence of the dolphins with the peak of their presence in the spring period. Our results will contribute to knowledge about ecological parameters of Delphinidae and Phocoenidae communities to develop a comprehensive dolphin conservation program locally in the study area and along the entire south-western Black Sea coast.

Common dolphin observed near Zonguldak (Türkiye)

Well-marked common dolphin individual

Bottlenose dolphin with İD number Z024

Bottlenose dolphin with amputated dorsal fin

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