Caitlin R. Nicholls

Introduction: Social structure plays a crucial role in shaping the transmission dynamics of infectious diseases within animal populations, yet its influence remains understudied in marine mammals. Aims: This review investigates links between marine mammal sociality and disease vulnerability, focusing on social network metrics and their influence on disease transmission. The study aimed to (1) identify patterns in disease transmission, (2) map gaps in current knowledge to inform strategic directions for future investigation and (3) discuss implications for conservation and disease management. Methods: Through systematic database searching, 14 studies were identified that investigated social network metrics and their influence on disease transmission in marine mammal social networks. Results: Results show that stronger associations and greater social connectivity increase disease prevalence, although this relationship varied across species. Central individuals acted as ‘super‐spreaders’, facilitating disease spread to conspecifics and vaccination efforts targeting these individuals are a recurrent proposed mitigation strategy. At the population level, network fragmentation reduced disease burden, while highly connected subgroups facilitated pathogen transmission. Research is concentrated on few key species, revealing significant gaps in taxonomic and geographic representation. Additionally, studies were geographically biased toward North America and Australia, with limited collaboration across research clusters, highlighting the need for broader representation and interdisciplinary partnerships. Conclusion: These findings underscore the need for interdisciplinary approaches integrating epidemiological modelling, social network analysis and conservation strategies to better predict and mitigate disease risks in marine mammal populations. Future research should expand species coverage and incorporate ecological and environmental variables to develop targeted disease management frameworks.

The ecology and evolution of prey populations are influenced by predation and predation risk. Our understanding of predator–prey relationships between sharks and dolphins is incomplete due to the difficulties in observing predatory events directly. Shark‐inflicted wounds are often seen on dolphin bodies, which can provide an indirect measure of predation pressure. We used photographs of Australian humpback and snubfin dolphins from north, central, and south Queensland to assess the incidence of shark‐inflicted bite injuries and to examine interspecific differences in bite injuries and their relationship with group sizes, habitat features, and geographical locations characteristic of where these individuals occurred. The incidence of shark‐inflicted scarring did not differ between species (χ² = 0.133, df = 1, p = .715), with 33.3% of snubfin and 24.1% of humpback dolphins showing evidence of shark bites when data were pooled across all three study sites. Generalized additive models indicated that dolphins closer to the coast, with greater photographic coverage, and in north Queensland were more likely to have a shark‐inflicted bite injury. The similar incidence of shark‐inflicted wounds found on snubfin and humpback dolphins suggests both are subject to comparable predation pressure from sharks in the study region. Results highlight the importance that habitat features such as distance to the coast and geographical location could have in predation risk of dolphins from sharks, as well as the importance of considering photographic coverage when assessing the incidence of shark‐inflicted bites on dolphins or other marine animals. This study serves as a baseline for future studies on shark‐dolphin interactions in Queensland and into how predation may influence dolphin habitat usage, group living, and behavior.