ATTACHMENT SITE SPECIFICITY AND THE TAPEWORM ASSEMBLAGE IN THE SPIRAL INTESTINE OF THE BLUE SHARK (PRIONACE GLAUCA)

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, Pro- sobothrium armigerum, Paraorygmatobothrium prionacis, and Anthobothrium laciniatum. Each individual shark hosted 1-4 tapeworm species (F = 3.7 ? 0.65). The 12 sharks in which both sides of the mucosal scroll were examined hosted 156-2,382 (Fc = 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. As a result, all site analyses were conducted on a worms/cm2 basis. Wilcoxon-Mann-Whitney tests revealed no significant differences in worm density between the inside and the outside of the mucosal sheet or between the region proximal to the roll and the region distal to the roll. But, Wilcoxon-Mann-Whitney tests revealed that all of the species except P. prionacis exhibited a preference for attachment to the anterior one-half of the mucosal sheet. Evidence of interaction among the species in this assemblage was not found. One shark was parasitized by the single species P. armigerum; this species was found in the same region in this shark as it was when it was present in sharks with 1 or more other species. There was some evidence of underutilized resources. Five of the 12 sharks in which both sides of the mucosal sheet were studied had vacant posterior quarters; 12 out of the 24 sharks examined had vacant posterior quarters on 1 or both sides of the intestinal scroll. The blue shark hosted a comparable number of parasite species but a greater number of parasite individuals than reported previously for the parasite assemblages in the gastrointestinal tract of other elasmobranch species.