Date of Award


Level of Access

Campus-Only Thesis

Degree Name

Master of Science (MS)


Ecology and Environmental Sciences


Mario Teisl

Second Committee Member

Kathleen P. Bell

Third Committee Member

Caroline Noblet


The Maine Center for Disease Control and Prevention (CDC) distributes a mercury advisory describing safe eating guidelines for fish to healthcare providers. We evaluate the effectiveness of Maine CDC's updated 2005 mercury advisory that informs at-risk women of childbearing age, about the benefits and risks of fish consumption. Maine's mercury advisory targets this at-risk group because eating fish provides health benefits, particularly during pregnancy; however, nearly all fish contain methylmercury which can impair human health. Thus, the advisory informs women about high-mercury and low-mercury fish with the goal of inducing shifts in consumption away from high-mercury to low-mercury fish while encouraging fish consumption.

This evaluation of the advisory updates a study completed by the School of Economics at the University of Maine on the 2000 mercury advisory and brochure. The most important finding from this previous study indicated that the advisory induced appropriate switching behavior; women reading the advisory decreased their consumption of high-mercury fish and increased their consumption of low-mercury fish.

Maine CDC's new advisory emphasizes the benefits of eating fish, clarifies the risk/benefit message, provides increased information on fish bought in stores and restaurants, and offers examples of fish with low amounts of mercury and high amounts of omega-3 fish oils. Two varieties of tuna, light and white (albacore), are specifically highlighted in the advisory because pre-packaged tuna is the most commonly eaten fish in the United States and white tuna has higher mercury levels than light tuna. In the advisory, pre-packaged salmon is encouraged as a substitute for both tuna varieties because it contains low-mercury levels and high omega-3 levels.

This analysis evaluates the 2005 advisory's effectiveness with a mixed mode survey. Beginning in September 2011, we sent a random sample of 1,500 women in Maine that had given birth in the previous three months a paper questionnaire with a letter describing the study and an alternative option to take the survey online. The questionnaire consisted of 55 questions intended to assess respondents' awareness of the mercury advisory, receipt of the new advisory, knowledge of risks and benefits associated with fish consumption and behavior changes in fish and/or omega-3 consumption. Overall response rate is 42% with a final sample of 597 respondents.

Women who read the advisory were more aware and knowledgeable of safe fish consumption than their non-reading counterparts. Respondents that read the advisory increased their consumption of low-mercury, high omega-3 pre-packaged salmon and decreased their consumption of high-mercury white tuna during pregnancy. Readers were also more likely to actually increase their consumption of low-mercury fish during pregnancy instead of the conventional overall reduction in fish. Our study determines if the Maine CDC's advisory has sufficiently increased women's knowledge about risks and benefits associated with eating fish to induce informed and appropriate nutrition decisions during pregnancy. Most of the literature examines awareness of mercury advisories and high mercury fish; this study adds to the literature by evaluating knowledge and behavior changes specifically associated with the health benefits of safe fish consumption during pregnancy.