Grantee Research Project Results

The Mechanisms and Effects of Endocrine Disruption on Infertility in the Bonnethead Shark on Florida's Gulf Coast

EPA Grant Number: R826128
Title: The Mechanisms and Effects of Endocrine Disruption on Infertility in the Bonnethead Shark on Florida's Gulf Coast
Investigators: Manire, Charles A. , Cortes, Enric , Rasmussen, L. E.L.
Current Investigators: Manire, Charles A. , Cortes, Enric , Rasmussen, L. E.L. , Gelsleichter, James
Institution: Mote Marine Laboratory , Oregon Graduate Institute of Science & Technology , Florida State University
Current Institution: Mote Marine Laboratory , Oregon Graduate Institute of Science & Technology , National Marine Fisheries Service
EPA Project Officer: Aja, Hayley
Project Period: January 1, 1998 through December 31, 2001
Project Amount: $399,653
RFA: Endocrine Disruptors (1997) RFA Text | Recipients Lists
Research Category: Environmental Justice , Endocrine Disruptors , Human Health , Safer Chemicals

Description:

Objectives/hypotheses: The objectives of this proposed study are: 1) to determine the degree to which the infertility observed in the bonnethead shark (Sphyrna tiburo) in the Tampa Bay/Anclote River area of Florida is caused by disruption of the shark's endocrine system; 2) to determine the mechanism[s] of such disruption; 3) to determine if this infertility is correlated with organochlorine levels in the shark's serum and/or liver; and 4) to estimate the effects that the infertility rates, as well as other possible effects of the contaminants, observed in three different geographical areas, may have on the rate of population growth of the species in the different areas. With regard to these objectives, field observations, published data and preliminary studies have allowed the formulation of the following hypotheses: 1) infertility observed in female bonnethead sharks, in the form of infertile ova maintained in the uterus throughout gestation, is caused by a disruption to the endocrine system, either in the male during sperm production or storage, or in the female during sperm storage; and 2) infertility in bonnethead sharks is correlated with the presence of environmental contaminants, especially organochlorines.

Approach:

This study will involve the collection of samples from S. tiburo populations in three different geographical areas exposed to three different levels of human impact. One is a highly populated, highly industrialized area, the second is less populated and non-industrialized, and the third is a relatively uncontaminated habitat. The study will utilize histological and immunocytochemical techniques, radioimmunoassay of steroid hormones (reproductive and glucocorticoids), sperm counts and sperm viability measurements, gas chromatography/mass spectrometry, routine ageing techniques and demographics to compare the reproductive attributes, stress levels, organochlorine levels in the shark's serum and liver in these three populations, and to assess the impact of the infertility, as well as other possible effects of the contaminants, on the population parameters of each population.

Expected Results:

The successful completion of the study will allow for the determination of whether infertility is correlated with an environmental contaminant, the determination of risk assessment for populations of these sharks in the Florida Gulf coastal areas, and will allow for the estimation of possible effects on other commercially and ecologically important shark species, other marine life and humans that share contaminant exposure with S. tiburo. Upon the successful completion of this study, this species could be used as an indicator species to monitor the contaminants and thereby be useful in risk assessment and management in these and other areas where the species occurs.

Publications and Presentations:

Publications have been submitted on this project: View all 13 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 8 journal articles for this project

Supplemental Keywords:

marine environment, estuarine habitat, risk assessment, elasmobranchs, organochlorines, histology, reproduction, hormones, infertility, RFA, Health, Scientific Discipline, Environmental Exposure & Risk, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, Limnology, Ecosystem/Assessment/Indicators, Ecosystem Protection, exploratory research environmental biology, Environmental Chemistry, wildlife, Endocrine Disruptors - Environmental Exposure & Risk, Ecological Effects - Environmental Exposure & Risk, endocrine disruptors, Risk Assessments, Biochemistry, Southeast, Children's Health, Histology, Endocrine Disruptors - Human Health, Ecological Indicators, EPA Region, ecological exposure, ecological effects, risk assessment, region 4, Anclote River, Gulf Coast, Florida Bay, elasmobranchs, estuarine habitat, fish, infertility, bonnethead shark, organochlorine compounds, Tampa Bay, ecological impacts, Apalachicola Bay, reproduction, reproductive processes, reproductive health, Florida Gulf Coast, Florida

Progress and Final Reports:

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.