In response to the Gulf of Mexico oil spill, scientists from the Commonwealth Scientific and Industrial Research Organization (CSIRO) conducted on-site monitoring of dispersed oil at the request of BP. This dataset contains structured content and unstructured content. The structured content is the CSIRO shipboard measurements including CTD vertical profiles, towed fluorometry, onboard hydrocarbon sensors and GCMS data. Unstructured content is associated with shipboard measurements, including photos, raw data files/casts, cast profiles, sonar contacts, daily reports and cruise summaries. Included in this data product are CSIRO documentation with detailed information in a database data dictionary and manifest.