Expert consultation and Epidemiological study results for fish parasites Ceratothoa oestroides, Enteromixum leei and Sparicotyle chrysophrii dataset https://portal.medin.org.uk/portal/start.php?tpc=009_CEFAS2d3352dd-a679-48cb-82ba-50a38bf6740a This dataset comprises the results of an expert consultation and epidemiological study conducted by Cefas and partners, as part of the Parafish Control project. The data were collected in order to produce a farm level modelling tool which fish farmers can use to assess the potential economic impact of parasites *Ceratothoa oestroides*, *Enteromixum leei* and *Sparicotyle chrysophrii *at the farm level. The relative risk posed to a potential or existing site based on characteristics such as the number of supplying hatcheries, and number of farms operating in the area. Site management practices such as frequency of mortality removal, use of fallowing, and frequency of net changes are also considered, and farmers are offered the chance to consider the cost associated with changing their practices to a lower risk option. The underlying data used in the model calculations are yet to be published (as of 12/11/2019). They are derived from two connected studies which are described briefly below. The first of these was an expert consultation. Various risk factors associated with the introduction and proliferation of these parasites at aquaculture sites were identified and an online questionnaire exploring their impacts in relation to these risk factors was completed independently by a group of experts (veterinarians, officials etc.). A Delphi style consultation meeting was then held, where the questionnaire results were presented by a moderator and discussed by the experts, and agreement reached on numerical values. The second study collected information from 39 mediterranean cage farms. The information collected covered the same range of risk factors as the previous study (farm location, size, environment, management and husbandry practices) together with information on their experience with the parasites (presence, associated mortalities and growth retardation, parasite monitoring and treatment). The .csv files contain a subset of all the data collected which are relevant to the economic model, the factors having been determined based on statistical significance and practical relevance. The full datasets from the two studies are not available at present. The data and associated reports are Confidential within the Parafish project but are being developed into peer-reviewed manuscripts. Links will be provided when these are published. The economic model can be found `here`_. .. _`here`: https://openscience.cefas.co.uk/parafish_economic/ 20191115 20191108