Living in a harsh habitat: epidemiology of the whale louse, Syncyamus aequus (Cyamidae), infecting striped dolphins in the Western Mediterranean

• Published in: Journal of Zoology
• Main Authors: Fraija‐Fernández, N., Fernández, M., Gozalbes, P., Revuelta, O., Raga, J. A., Aznar, F. J.
• Other Authors: Ministerio de Economía y Competitividad, Generalitat Valenciana
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2017
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; baleen whales
• Online Access: http://dx.doi.org/10.1111/jzo.12482; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fjzo.12482; https://onlinelibrary.wiley.com/doi/pdf/10.1111/jzo.12482; https://onlinelibrary.wiley.com/doi/full-xml/10.1111/jzo.12482; https://zslpublications.onlinelibrary.wiley.com/doi/pdf/10.1111/jzo.12482

Abstract Whale lice (Cyamidae) are ectoparasitic amphipods exclusive to cetaceans. Data on their epidemiology usually come from species infecting baleen whales, which are large, slow‐moving hosts. In this study, we provide data on infection parameters, population structure and microhabitat selection in a whale louse exclusive to delphinids, Syncyamus aequus, with the aim of comparing them with those from cyamid species from large whales. A total of 176 striped dolphins Stenella coeruleoalba stranded along the Mediterranean coast of Spain during 1980–2016 were examined. The prevalence of S. aequus was 27.3% (95% CI : 20.9–34.3), and populations were sparse, with a mean number of whale lice per infected host of just 4.5 (3.4–6.7). The parasites were found on the head, with a clearly nested pattern, with the blowhole being the most frequently occupied site, followed by the mouth corner and eyes. Single‐male or single‐female populations were found on as much as 39.6% of infected dolphins. The sex ratio did not significantly depart from 1:1. Females were significantly larger than males and exhibited low fecundity (<10 eggs). The sex or the age class of the dolphins did not significantly affect the abundance or population structure of S. aequus . The patterns here obtained are in sharp contrast with those reported for whale lice infecting large whales. The small, streamlined body of dolphins creates strong current flows that would restrict the amount of suitable microhabitats and the body size of their associated cyamids. This would limit population growth, which in turn would lower the chances of host‐to‐host transmission upon body contacts, as well as male competition for the access to females.