Consumption Surveys for Fish and Shellfish: A Review and Analysis of Survey Methods

Although several studies have demonstrated that fish and shellfish consumption rates differ both regionally and within specific subpopulations, most States do not have available sufficient data to calculate local consumption rates or to identify special populations at risk. Examples of these special populations are recreational and subsistence anglers and members of their households - in particular, women of child-bearing age, children, and the elderly - who frequently consume fish obtained from contaminated sites. This report was designed as a critical assessment of fish tissue consumption rate survey approaches and methods and their applicability for estimating consumption rates in recreational and subsistence fishing populations. Additional information is provided to assist Federal and State agencies in developing appropriate surveys to answers questions and resolve issues related to fish consumption rates of special populations. Five approaches to obtaining fish consumption data were reviewed: (1) recalling information collected by telephone; (2) recalled information collected by in-person (face-to-face) interviews; (3) recalled information requested on self-administered mailed questionnaires; (4) diaries maintained by anglers; and (5) on-site creel censuses. The effectiveness of the approach used to obtain adequate information for fish consumption rate calculations varied with the objective(s) of the survey. For example, creel censuses usually failed to collect data on consumption. Many surveys combined two or more approaches in order to maximize the number of respondents or validate the information obtained. Several studies addressed actual contaminant exposures through physical examinations and measurement of blood serum levels of contaminants, while other investigated risk perception and compliance with fish consumption advisories and bans by the targeted anglers. Five elements common to all surveys have been identified, and specific methodological details are provided to help solve problems that may be encountered when undertaking a fish consumption survey. (1) Survey design must address the purpose for which the survey is to be conducted, the resources available for carrying it out, including time and funding available, and the approach to be used. (2) Survey participants should be identified from a pool of subsistence or recreational anglers, and the method by which the sample is selected may vary depending on the approach that will be used to collect the data and how the data will be analyzed. (3) The information to be collected should examine sociodemographic factors that may influence fish consumption rates, minimizing the number of assumptions that could compromise results. The survey length and complexity should be carefully considered in order to elicit maximum cooperation from respondents. (4) Appropriate quality assurance procedures need to be developed before beginning the survey, and quality control must be carefully monitored during the survey to ensure the validity of the data before statistical analysese are conducted. (5) Data processing procedures and statistical analyses should be performed to provide the desired information and correlations.