Sheepshead minnows, Cyprinodon variegatus, an estuarine fish, is heavily parasitized in the bulbus arteriosus by the heterophyid trematode Ascocotyle pachycystis, in channels and sloughs throughout the St. Mark's National Wildlife Refuge, northwestern Florida. I conducted laboratory experiments to examine the morphological and physiological effects of parasites on these fish. Unparasitized and parasitized fish were compared for differences in ventricle weight, cardiac performance, swimming performance, and oxygen consumption. / Parasitized fish hearts were hypertrophied, had larger contractile forces and shorter contractile periodicity, and decreased bulbal expansion. Swimming performance was significantly reduced at cold temperatures and low dissolved oxygen levels. Oxygen consumption increased in parasitized fish whiled swimming times to exhaustion decreased. / Field experiments were conducted in St. Mark's National Wildlife Refuge to determine seasonal variation in recruitment rates of A. pachycystis parasites into caged sheepshead minnows. Monthly fish collections were examined for intensities of infection and dispersion patterns. / Recruitment of parasites into caged fish is a warm-weather phenomenon, peaking in mid-summer and declining to zero over the winter. Susceptibility to infection is age-related. Mean intensities and prevalences are highest in the largest size classes; overdispersion is recruitment-induced, rather than mortality induced, except during the winter when it is specific to the oldest fish. / Source: Dissertation Abstracts International, Volume: 52-03, Section: B, page: 1190. / Major Professor: Joseph Travis. / Thesis (Ph.D.)--The Florida State University, 1991.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_76372 |
| Contributors | Coleman, Felicia Chisolm., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 114 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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