Attachment Site Specificity and the Tapeworm Assemblage in the Spiral Intestine of the Blue Shark (Prionace glauca)

Abstract

The parasite assemblage in the scroll-type spiral intestine of 24 specimens of the blue shark Prionace glauca collected off of Montauk, Long Island, New York was investigated. When opened with a longitudinal incision to the right of the ventral blood vessels, the internal mucosal spiral of the spiral intestine of the blue shark could be unrolled into a flat sheet of double-sided mucosal tissue. Attachment sites and parasite assemblages were studied on both sides of the sheet in 12 sharks and on either the inside or the outside of the sheet in 12 additional sharks. Assemblages within host individuals were composed of up to 4 species of tetraphyllidean cestodes including the onchobothriid Platybothrium auriculatum, and the phyllobothriids, Prosobothrium armigerum. Paraorygmatobothrium prionacis, and Anthobothrium laciniatum. Each individual shark hosted 1-4 tapeworm species (mean = 3.7 +/- 0.65). The 12 sharks in which both sides of the mucosal scroll were examined hosted 156-2,382 (mean = 929.1 +/- 818) individual tapeworms. The assemblage consisted of 4 core species. Sharks were not found to host all of the possible combinations of species in their assemblages; the most common combination (17 out of 24 individuals) was the occurrence of all 4 parasite species. A chi-square test revealed no evidence that the 4 species did not occur independently. Regression revealed a significant relationship between shark total length and spiral intestine area. Analysis of covariance (ANCOVA) revealed a significant difference between the surface areas of the 2 sides of the mucosal sheet when shark total length was taken into account.(ABSTRACT TRUNCATED AT 250 WORDS)