Intestinal helminth fauna of striped dolphins (Stenella coeruleoalba) in the western Mediterranean: No effects of host body length, age and sex

The intestine of 52 (28 males and 24 females) striped dolphins (Stenella coeruleoalba) from western Mediterranean waters was examined for helminths. Animals were found stranded along the Spanish coasts during the morbillivirus epizootic in 1990. In accordance with observations from other pelagic tetrapods, including cetaceans from other geographical regions, the intestinal helminth community was depauperate. Four helminth species were found: three tetrabothriid cestodes, Tetrabothrius forsteri (prevalence: 96.2%; mean intensity [95% CI]: 47.4 [34.4-68.2]), Trigonocotyle globicephalae (9.6%; 1.8 [1.0-2.2]), and Strobilocephalus triangularis (23.1%; 5.3 [2.9-10.2]), and immature individuals of the acanthocephalan Bolbosoma vasculosum (51.9%; 2.7 [2.0-3.4]). Schluter's variance test indicated a weak, but statistically significant association of occurrence of helminth species in dolphins, suggesting that some tetrabothriid species might use the same intermediate or paratenic hosts. Neither the abundance of helminth species nor infracommunity descriptors were significantly affected by sex, host body length or age. The absence of predictable effects of body size and age on the recruitment rate of helminths could be related to the fact that the host sample was largely composed of adults. This study provides quantitative evidence about helminth community structure of striped dolphins, based on a large sample size.