Crop grouping: a proposal for public aquaculture

Production in US aquaculture is limited by the few FDA-approved drugs available for use. The problem is compounded by the high costs and long time frames associated with extending the approved label of an existing drug to treat additional fish species. An FDA approved crop grouping plan could significantly reduce the costs associated with extending or expanding the label of a currently approved drug to other species. Before FDA could sanction such a plan, they require scientific data with which to make an informed decision. Under a crop grouping plan, a surrogate fish species would represent a single group of fish for the purposes of gaining drug approvals. The concept, if practical, would conserve substantial public resources expended to gain drug approvals and yet give regulators assurance that the extended label use provides necessary regulatory safeguards to protect human food safety and the environment. A crop grouping plan should include development of a data base that is sufficiently sensitive to discriminate differences of one group from another and yet would be able to identify potential similarities between like-species for grouping. The proposed crop grouping action plan should include data sets for fish grouped by temperature preference, activity level, and phylogenetic classification. Initially, two representative species would be identified for testing as surrogates for candidate groups; rainbow trout representing a coldwater, active, and conservative phylogenetic group, and channel catfish representing a warmwater, relatively sedentary and more phylogenetically advanced group. Additional species representing more primitive (sturgeon) and more advanced (striped bass and walleye) groups would be added. A waterborne (benzocaine) and an orally administered drug (sarafloxacin) would initially be tested among the major species groups. The integrity of the group will be tested by comparing the variability of response between major species against variability within cohort species identified for inclusion within each specific group.